Unit battery cell manufacturing device and method

Abstract

In order to solve the problem, an apparatus for manufacturing a unit battery cell according to an embodiment of the present invention includes: an electrode reel, from which an electrode sheet forming a plurality of electrodes is unwound; a diaphragm reel, from which a diaphragm sheet laminated with the electrodes is unwound; and a sealer, wherein the sealer is arranged between the plurality of electrodes, and each sealer applies heat and pressure to at least one of a corner of the electrode and an edge of the electrode with respect to a laminate formed by laminating a plurality of electrodes with the diaphragm sheet, and the plurality of electrodes are arranged in a row in the longitudinal direction of the diaphragm sheet while being separated from each other.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2020-0036392, filed on Mar. 25, 2020, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0004] The present invention relates to a unit cell manufacturing apparatus and method, and more particularly, to a unit cell manufacturing apparatus and method capable of preventing a decrease in adhesive force of a unit cell side portion. Background Art

[0005] Generally, the types of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries and lithium-ion polymer batteries. These secondary batteries are not only used in small products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, portable game devices, power tools and electric bicycles, but also in large products that require high output such as electric vehicles and hybrid vehicles, power storage devices and backup power storage devices that store the surplus power or renewable energy generated.

[0006] A single electrode assembly is formed by assembling unit cells, and each unit cell is formed by stacking a positive electrode, a separator, and a negative electrode. In addition, the electrode assembly is housed in a specific case, thereby manufacturing a lithium secondary battery.

[0007] These unit cells include full-cells and bi-cells. Each full-cell is a cell in which the positive electrode and the negative electrode are respectively arranged at the two outermost parts of the cell. As the most basic structure of a full-cell, there are positive electrode / diaphragm / negative electrode structure, positive electrode / diaphragm / negative electrode / diaphragm / positive electrode / diaphragm / negative electrode structure, etc.

[0008] Each dual cell is a cell in which electrodes with the same polarity are arranged at the two outermost parts of the cell. As the most basic structure of a dual cell, there are an A-type dual cell with a positive electrode / diaphragm / negative electrode / diaphragm / positive electrode structure, a C-type dual cell with a negative electrode / diaphragm / positive electrode / diaphragm / negative electrode structure, and the like. That is, a cell in which the positive electrode is arranged at its two outermost parts is called an A-type dual cell, and a cell in which the negative electrode is arranged at its two outermost parts is called a C-type dual cell.

[0009] Generally, to prepare such a unit cell, while the middle electrode is moved to one side by a conveyor belt, etc., the separators are stacked on the upper and lower surfaces of the middle electrode, respectively, and thereafter, the upper and lower electrodes are stacked. If the unit cell is a double cell, an odd number of middle electrodes such as 1 may be provided, and if the unit cell is a full cell, an even number of middle electrodes such as 2 may be provided.

[0010] In addition, it is very important to evaluate and ensure the safety of the electrode assembly. First of all, it should be considered that errors in the operation of the electrode assembly should not cause damage to the user. For this purpose, safety regulations strictly regulate fire and explosion in the electrode assembly. Among the safety characteristics of the electrode assembly, thermal runaway caused by overheating of the electrode assembly or puncture of the diaphragm increases the risk of explosion. In particular, the polyolefin-based porous substrates generally used as electrode assembly diaphragms exhibit extreme thermal shrinkage behavior at 100°C or higher due to the characteristics of their materials and their manufacturing processes (such as elongation), thereby causing an electrical short circuit between the positive and negative electrodes.

[0011] In order to solve the above safety-related problems of the electrode assembly, a separator having a porous organic-inorganic coating is proposed, which is formed by coating at least one surface of a porous polymer substrate having a plurality of pores with a slurry containing a mixture of excess inorganic particles and a polymer binder. Since the inorganic particles contained in the porous organic-inorganic coating have excellent heat resistance, even when the electrode assembly is overheated, an electrical short circuit between the positive electrode and the negative electrode is prevented.

[0012] However, when the porous coating is coated thinly (for example) to a thickness of less than 3 μm (based on the cross section of the porous substrate), the adhesion between the diaphragm and the electrode is insufficient, resulting in reduced assembly properties. When the adhesion between the diaphragm and the electrode is excellent, the increase in interfacial resistance caused by the separation of the diaphragm and the electrode due to the gas generated as the electrolyte dissociation product during the electrode assembly cycle can be prevented. In addition, the increase in interfacial resistance between the diaphragm and the electrode due to the volume expansion of the electrode during the cycle can be prevented, and the strength of the electrode assembly can be improved by suppressing the bending of the electrode assembly in the form of jelly rolls or stacking and folding. In this regard, the adhesion between the diaphragm and the electrode is a very important factor in electrode assembly.

[0013] Figure 1 2 is a schematic diagram illustrating the non-adhesive region 22 of the unit cell 2 .

[0014] In the prior art, the diaphragm 12 ( Figure 2 ) is by applying a polymer substrate 123 ( Figure 2 ) to form a porous coating 124 ( Figure 2 In addition, electrode 11 ( Figure 4) is stacked on the diaphragm 12, and heat and pressure are applied thereto to produce Figure 1 The unit cell 2 shown in FIG.

[0015] However, since the porous coating layer 124 is formed by applying a liquid or gel slurry onto the polymer substrate 123 and then curing it, even if the slurry is applied uniformly, there is a certain height difference from the surface. In particular, the slurry is formed in the middle portion 125 ( Figure 2 ) than its side 126 ( Figure 2 125) is accumulated more, so the height of the slurry is formed lower in the side portion 126 than in the middle portion 125. Therefore, in the side portion 126 and the middle portion 125 of the separator 12, there is a height difference even in the porous coating layer 124 obtained by curing the slurry, and therefore, even if the electrodes 11 are stacked to manufacture the unit cell 2, the adhesion of the separator 12 is deviated. Therefore, as Figure 1 As shown in , there is a problem that the electrode 11 and the separator 12 are not adhered to each other or are poorly adhered to each other, thereby forming a non-adhesive region 22 on a portion of the side portion 21 of the unit cell 2.

[0016] As a prior art document, there is Korean Patent Application Publication No. 2017-0057251. Summary of the invention

[0017] Technical issues

[0018] An aspect of the present invention provides a unit cell manufacturing apparatus and method capable of preventing a decrease in adhesive force at a side portion of a unit cell.

[0019] The objects of the present invention are not limited to the above-mentioned objects, but other objects not described herein will be clearly understood by those skilled in the art from the following description.

[0020] Technical Solution

[0021] According to one aspect of the present invention, a unit cell manufacturing device is provided, which includes: an electrode reel, from which an electrode sheet that will become a plurality of electrodes is unwound; a diaphragm reel, from which a diaphragm sheet stacked with the electrodes is unwound; and a sealer, in a stack formed by stacking the plurality of electrodes with the diaphragm sheet while the plurality of electrodes are separated from each other and arranged in rows in the longitudinal direction of the diaphragm sheet, the sealer being arranged between the plurality of electrodes and applying heat and pressure to at least one of the corners of the electrode or the edges of the electrode.

[0022] In addition, the sealer may include: a first body; and a second body vertically extending from the first body.

[0023] In addition, the sealer may further include: a first protrusion protruding downward from the lower surface of the first body and extending in the longitudinal direction of the first body; and a second protrusion protruding downward from the lower surface of the second body and extending in the longitudinal direction of the second body.

[0024] In addition, the apparatus may further include a laminator for laminating the stack.

[0025] Additionally, the laminate may include a heater that applies heat and pressure to the entire surface of the stack.

[0026] Additionally, the laminate may further include a heating roller that applies heat and pressure to the stack while rotating.

[0027] In addition, the electrode reel may include a middle electrode reel, from which middle electrode sheets that will become multiple middle electrodes are unwound, and the diaphragm reel may include: an upper diaphragm reel, from which an upper diaphragm sheet stacked on the upper surface of the middle electrode formed by cutting the middle electrode sheet is unwound; and a lower diaphragm reel, from which a lower diaphragm sheet stacked on the lower surface of the middle electrode is unwound.

[0028] In addition, the electrode reel may also include: an upper electrode reel, from which an upper electrode sheet to be stacked on the upper surface of the upper diaphragm sheet is unwound; and a lower electrode reel, from which a lower electrode sheet to be stacked on the lower surface of the lower diaphragm sheet is unwound.

[0029] According to one aspect of the present invention, a unit cell manufacturing method is provided, which includes the following steps: cutting an electrode sheet unwound from an electrode reel to form a plurality of electrodes; forming a stack by stacking the plurality of electrodes on a diaphragm sheet while separating the plurality of electrodes from each other and arranging them in rows in the longitudinal direction of the diaphragm sheet unwound from a diaphragm reel; arranging a sealer between the plurality of electrodes in the stack; and applying heat and pressure to at least one of the corners of the electrode or the edges of the electrode using the sealer.

[0030] In addition, the sealer may include: a first body; and a second body vertically extending from the first body.

[0031] In addition, when applying heat and pressure, the first body can apply heat and pressure to a first edge among the edges of the electrode that points to the outside of the stack, and the second body can apply heat and pressure to a second edge among the edges of the electrode that faces another adjacent electrode and intersects with the first edge to form a corner.

[0032] In addition, the sealer may further include: a first protrusion protruding downward from the lower surface of the first body and extending in the longitudinal direction of the first body; and a second protrusion protruding downward from the lower surface of the second body and extending in the longitudinal direction of the second body.

[0033] In addition, when applying heat and pressure, the first protrusion can apply heat and pressure to a first area of ​​the diaphragm sheet extending outward from the first edge of the electrode, and the second protrusion can apply heat and pressure to a second area of ​​the diaphragm sheet formed between the multiple electrodes.

[0034] Additionally, the method may further include laminating the stack after forming the stack and before providing the sealer.

[0035] In addition, the laminating may further include: applying heat and pressure to the entire surface of the stack by a heater; and applying heat and pressure to the stack by a heating roller while the heating roller rotates.

[0036] Other specific details of the invention are included in the detailed description and the accompanying drawings.

[0037] Beneficial Effects

[0038] The embodiments of the present invention can have at least the following effects.

[0039] In a stack formed by stacking a plurality of electrodes on a separator sheet, the sealer applies heat and pressure to at least one of the corners of the electrode or the edges of the electrode, so that it can prevent the formation of non-bonding areas on the sides of the unit cells, thereby preventing the bonding force between the electrode and the separator from decreasing.

[0040] The effects according to the present invention are not limited to the contents as exemplified above, but include more various effects in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic diagram illustrating a non-bonded area of ​​a unit cell;

[0042] Figure 2 is a schematic diagram of a diaphragm according to an embodiment of the present invention;

[0043] Figure 3 is a flow chart of a method for manufacturing a unit cell according to an embodiment of the present invention;

[0044] Figure 4 is a schematic diagram of a unit cell manufacturing apparatus according to an embodiment of the present invention;

[0045] Figure 5 is a perspective view of a sealer according to an embodiment of the present invention;

[0046] Figure 6 is a plan view illustrating a state in which a sealer according to an embodiment of the present invention applies heat and pressure to a stack;

[0047] Figure 7 is a side view illustrating a state in which a sealer according to an embodiment of the present invention applies heat and pressure to a stack;

[0048] Figure 8 is a schematic diagram of a unit cell manufacturing device according to another embodiment of the present invention;

[0049] Fig. 9 is a perspective view of a sealer according to another embodiment of the present invention; and

[0050] Fig.10 is a side view illustrating a state in which a sealer according to still another embodiment of the present invention applies heat and pressure to a stack. DETAILED DESCRIPTION

[0051] The advantages and features of the present invention and methods for implementing the same will be explained by the following embodiments described with reference to the accompanying drawings. However, the present invention can be implemented in different forms and should not be understood as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be thorough and complete and will fully convey the scope of the present invention to those skilled in the art. In addition, the present invention is limited only by the scope of the claims. The same reference numerals always refer to the same elements.

[0052] Unless otherwise defined, all terms (including technical and scientific terms) used herein may be intended to have meanings generally understood by those skilled in the art. In addition, unless clearly and obviously defined in the specification, terms defined in commonly used dictionaries are not ideally or excessively interpreted as having formal meanings.

[0053] The terms used herein are only for the purpose of describing specific example embodiments and are not intended to limit the present invention. In this specification, terms in the singular may include plural forms unless otherwise indicated. It should also be understood that the term "include" and / or its variations when used in this specification indicate the presence of the components, without excluding the presence or addition of one or more other components.

[0054] Hereinafter, preferred embodiments will be described in detail with reference to the accompanying drawings.

[0055] Figure 2 is a schematic diagram of a separator 12 according to an embodiment of the present invention.

[0056] like Figure 2 As shown in , the separator 12 according to the embodiment of the present invention is prepared by coating a slurry including a mixture of inorganic particles and a polymer binder on at least one surface of a porous polymer substrate 123 to form a porous coating layer 124 .

[0057] Porous polymer substrate 123 is not limited to but includes various substrates, as long as it is a planar porous substrate such as a porous polymer film substrate or a porous polymer non-woven fabric substrate commonly used in electrode assemblies, such as a porous polymer film substrate formed by various polymers or a porous polymer non-woven fabric substrate. For example, a polyolefin porous polymer film such as polyethylene or polypropylene or a non-woven fabric made of polyethylene terephthalate fiber used as a separator 12 in an electrode assembly (especially, a lithium secondary battery) can be used, and their material or form can be selected in various ways according to the desired purpose. The polyolefin porous polymer film can be formed by a polyolefin polymer, for example, by polyethylene, polypropylene, polybutene, polypentene (independently or as a mixture thereof) such as high-density polyethylene, linear low-density polyethylene, low-density polyethylene and ultra-high molecular weight polyethylene. In addition, in addition to polyolefins, various polymers such as polyester fibers can also be used to prepare porous polymer film substrates. In addition, the porous polymer substrate can be formed into the following structure: two or more film layers are stacked, and each film layer can be formed by a polymer such as polyolefin and polyester fibers (independently or a mixture of two or more) as described above.

[0058] The porous polymer non-woven fabric substrate can be a non-woven fabric formed by a polymer, and the polymer includes a polyolefin polymer as described above, or other polymers with higher heat resistance, for example, polyethylene terephthalate, polybutylene terephthalate, polyester fiber, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene oxide, cycloolefin copolymer, polyphenylene sulfide, polyethylene naphthalate (independently or as a mixture thereof). In addition, the non-woven fabric can be a spunbond or melt-blown fabric composed of long fibers in the structure. However, the porous polymer substrate 123 is not limited thereto and can be selected differently in terms of material or form.

[0059] The thickness of the porous polymer substrate 123 is not particularly limited, but is preferably 1-100 μm, and more preferably 5-50 μm. In addition, the pore size and porosity in the porous polymer substrate 123 are not particularly limited, but are preferably 0.01-50 μm and 10-95%, respectively.

[0060] On at least one surface of the porous polymer substrate 123, a slurry containing a mixture of inorganic particles and a polymer binder is applied to form a porous coating layer 124. The coating method of the slurry is not limited, and various methods can be used, but a dip coating method is preferably used. Dip coating is a method of coating a substrate by immersing the substrate in a vat containing a coating solution, and the thickness of the porous coating layer 124 can be adjusted according to the concentration of the coating solution and the speed of taking the substrate out of the coating solution vat. Thereafter, the substrate is dried in an oven to form a porous coating layer 124 on at least one surface of the porous polymer substrate 123.

[0061] Inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles that can be used in the present invention are not particularly limited as long as no oxidation and / or reduction reaction occurs within the operating voltage range of the electrode assembly used (e.g., 0-5V relative to Li / Li+). In particular, when inorganic particles with a high dielectric constant are used as inorganic particles, this can help increase the dissociation rate of electrolyte salts such as lithium salts in liquid electrolytes, thereby improving the ionic conductivity of the electrolyte solution.

[0062] For these reasons, the inorganic particles preferably include high dielectric constant inorganic particles having a dielectric constant of 5 or more (preferably 10 or more). Non-limiting examples of inorganic particles having a dielectric constant of 5 or more may include, for example, BaTiO3, Pb(Zr,Ti)O3 (PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT,0 <x<1,0<y<1)、Pb(Mg 1 / 3 Nb 2 / 3 )O3-PbTiO3(PMN-PT), Hafnium dioxide(HfO2), SrTiO3, SnO 2、 CeO 2、 MgO, NiO, CaO, ZnO, ZrO 2、 Y2O3, Al2O3, boehmite (γ-AlO(OH)), TiO2, SiC or a mixture thereof.

[0063] In particular, such as BaTiO3, Pb(Zr,Ti)O3 (PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT), Pb(Mg1 / 3Nb 2 / 3Inorganic particles such as O3-PbTiO3 (PMN-PT) and hafnium dioxide (HfO2) exhibit high dielectric constant characteristics, that is, a dielectric constant of 100 or greater, and also have piezoelectricity because when a certain pressure is applied to them to cause them to expand or contract, charges are generated to create a potential difference between two surfaces, such that the above inorganic particles can prevent an internal short circuit of the two electrodes 11 caused by an external impact, thus improving the safety of the electrochemical device. Additionally, when the above-mentioned high dielectric constant inorganic particles and inorganic particles with lithium ion migration ability are used in combination, their synergistic effect can be doubled.

[0064] Inorganic particles with lithium ion migration ability can be used, that is, inorganic particles containing lithium element but having the function of enabling lithium ions to move without storing lithium. Because inorganic particles with lithium ion migration ability can cause lithium ions to migrate and move due to a kind of defect existing in the particle structure, the lithium ion conductivity in the battery can be improved, thereby improving the performance of the battery. Additionally, non-limiting examples of inorganic particles with lithium ion migration ability can include lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 < x < 2, 0 < y < 3), lithium aluminum titanium phosphate (Li x Al y Ti z (PO4)3, 0 < x < 2, 0 < y < 1, 0 < z < 3), such as (LiAlTiP) x O y -type glass such as 14Li2O-9Al2O3-38TiO2-39P2O5 (0 < x < 4, 0 < y < 13), lithium lanthanum titanate (Li x La y TiO3, 0 < x < 2, 0 < y < 3), such as Li 3.25 Ge 0.25 P 0.75 S4 such as lithium germanium thiophosphate (Li x Ge y P z S w , 0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5), such as lithium nitride (Li x N y , 0 < x < 4, 0 < y < 2), such as SiS2-type glass such as Li3PO4-Li2S-SiS2 (Li x Si y S z , 0 < x < 3, 0 < y < 2, 0 < z < 4), such as P2S5-type glass such as LiI-Li2S-P2S5 (Li x Py S z , where 0 < x < 3, 0 < y < 3, 0 < z < 7) or a mixture thereof.

[0065] The average particle size of the inorganic particles is not particularly limited, but is preferably in the range of 0.001 - 10 μm in order to form a porous coating 124 with a uniform thickness and ensure an appropriate porosity. If the average particle size is less than 0.001 μm, the dispersion properties of the inorganic particles will deteriorate. If the average particle size is greater than 10 μm, the thickness of the porous coating 124 to be formed will increase, which will deteriorate the mechanical properties. Additionally, during battery charging or discharging, an overly large pore size will increase the probability of internal short circuits.

[0066] A polymer having a glass transition temperature (Tg) in the range of -200°C to 200°C is preferably used as the polymer binder because the polymer can improve the mechanical properties such as flexibility and elasticity of the finally formed porous coating 124.

[0067] In addition, ionic migration ability is not essential for the polymer binder, but using a polymer with ionic migration ability can further improve the performance of the electrode assembly. Therefore, the polymer binder preferably has as high a dielectric constant as possible. In fact, since the degree of dissociation of salts in the electrolyte solution depends on the dielectric constant of the electrolyte solvent, as the dielectric constant of the polymer binder is higher, the degree of dissociation of salts in the electrolyte solution will increase. The dielectric constant of the polymer binder can be from 1.0 to 100 (measurement frequency = 1 kHz), preferably 10 or higher.

[0068] In addition to the functions mentioned above, when impregnated with a liquid electrolyte solution, the polymer binder can become gel-like and thus exhibit a high degree of swelling in the electrolyte solution. Therefore, a polymer having a solubility parameter in the range of 15 Mpa 1 / 2 to 45 Mpa 1 / 2 is preferably used, and more preferably in the range of 15 Mpa 1 / 2 to 25 Mpa 1 / 2 and 30 Mpa 1 / 2 to 45 Mpa 1 / 2 When the solubility parameter of the polymer is less than 15 Mpa 1 / 2 or higher than 45 Mpa 1 / 2 , it is difficult for the polymer to swell due to a typical battery electrolyte solution.

[0069] Non-limiting examples of polymer binders can include, for example, polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethyl methacrylate, polyacrylonitrile, polyvinyl pyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan and carboxymethyl cellulose.

[0070] In addition, the polymer binder may also include PVDF-HFP. The term "PVDF-HFP polymer binder" refers to a vinylidene fluoride copolymer including a vinylidene fluoride (VDF) constituent unit and a hexafluoropropylene (HFP) constituent unit. However, the polymer binder is not limited thereto and may include various materials.

[0071] The weight ratio of the inorganic particles to the polymer binder may preferably be, for example, in the range of 50:50 to 99:1, and more preferably in the range of 70:30 to 95:5. If the content ratio of the organic particles to the polymer binder is less than 50:50, the content of the polymer is very large, so that the pore size and porosity of the formed coating 124 may be reduced. If the content of the organic particles is greater than 99 parts by weight, the content of the polymer is very small, so that the peeling resistance of the formed coating 124 may be weakened.

[0072] The solvent for the polymer binder preferably has a solubility parameter close to the solubility parameter of the polymer binder to be used and a low boiling point. This is intended to facilitate uniform mixing and removal of the solvent thereafter. Non-limiting examples of available solvents may include, for example, acetone, tetrahydrofuran, dichloromethane, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane, water, or a mixture thereof.

[0073] The slurry in which the inorganic particles are dispersed and the polymer binder is dissolved in the solvent can be prepared by dissolving the polymer binder in the solvent and then adding the inorganic particles therein and dispersing them. The inorganic particles may be crushed into a suitable size and then added, but it is preferred that after adding the inorganic particles to the solution of the polymer binder, the inorganic particles are dispersed while being crushed using a ball mill or the like.

[0074] As described above, since the porous coating layer 124 is formed by applying a liquid or gel slurry onto the polymer substrate 123 and then curing it, even if the slurry is applied uniformly, there is a certain height difference d from the surface. In particular, since the attraction between the materials constituting the slurry acts more strongly on the side portion 126 than on the middle portion 125, the height of the slurry in the side portion 126 is formed lower than the height of the slurry in the middle portion 125. Therefore, as Figure 2As illustrated in FIG. 1 , there is a height difference in the side portion 126 and the middle portion 125 of the separator 12 even in the porous coating layer 124 obtained by curing the slurry, and therefore, even if the electrodes 11 are stacked to manufacture the unit cell 2, the adhesion of the separator 12 is deviated. Therefore, there is a problem that the electrode 11 and the separator 12 are not adhered to each other or are poorly adhered to each other, thereby forming a non-adhesive region 22 on a portion of the side portion 21 of the unit cell 2.

[0075] Figure 3 is a flowchart of a method for manufacturing a unit cell according to an embodiment of the present invention.

[0076] According to an embodiment of the present invention, in a stack 20 in which an electrode 11 is stacked on separator sheets 1211 and 1221, a sealer 14 applies heat and pressure to at least one of the corners of the electrode or the edges of the electrode, so that it can prevent the formation of a non-bonding area 22 on the side 21 of the unit cell 2, thereby preventing the bonding force between the electrode 11 and the separator 12 from being reduced.

[0077] To this end, a unit cell manufacturing method according to an embodiment of the present invention includes: cutting electrode sheets 1111, 1121 and 1131 unwound from electrode reels 111, 112 and 113 to form a plurality of electrodes 11; forming a stack 20 by stacking the plurality of electrodes 11 on the diaphragm sheets 1211 and 1221 while the plurality of electrodes 11 are separated from each other and arranged in rows in the longitudinal direction of the diaphragm sheets 1211 and 1221 unwound from the diaphragm reels 121 and 122; providing a sealer 14 between the plurality of electrodes 11 in the stack 20; and applying heat and pressure to at least one of the corners of the electrode 11 or the edges of the electrode 11 using the sealer 14.

[0078] In the following, reference will be made to Figure 4 and Figure 7 To describe in detail Figure 3 The steps are illustrated in the flowchart of FIG.

[0079] Figure 4 is a schematic diagram of a unit cell manufacturing apparatus 1 according to an embodiment of the present invention.

[0080] like Figure 4As illustrated in the figure, a unit cell manufacturing device 1 according to an embodiment of the present invention includes: electrode reels 111, 112 and 113, from which electrode sheets 1111, 1121 and 1131 that will become multiple electrodes 11 are unwound; diaphragm reels 121 and 122, from which diaphragm sheets 1211 and 1221 stacked with the electrodes 11 are unwound; and a sealer 14, in which, in a stack formed by stacking multiple electrodes with diaphragm sheets while the multiple electrodes 11 are separated from each other and arranged in rows in the longitudinal direction of the diaphragm sheets 1211 and 1221, the sealer 14 is arranged between the multiple electrodes 11 and applies heat and pressure to at least one of the corners of the electrode 11 or the edges of the electrode 11. In addition, the electrode reel may include a middle electrode reel 111 from which middle electrode sheets 1111 that will become multiple middle electrodes 1112 are unwound, and the diaphragm reels 121 and 122 may include: an upper diaphragm reel 121 from which an upper diaphragm sheet 1211 stacked on the upper surface of the middle electrode 1112 formed by cutting the middle electrode sheet 1111 is unwound; and a lower diaphragm reel 122 from which a lower diaphragm sheet 1221 stacked on the lower surface of the middle electrode 1112 is unwound.

[0081] As described above, the unit cell 2 includes a full cell and a double cell. As described above, if the unit cell 2 is a double cell, an odd number of middle electrodes 1112 such as 1 may be provided, and if the power cell 2 is a full cell, no middle electrode 1112 may be provided or an even number of middle electrodes 1112 such as 2 may be provided. Hereinafter, the unit cell 2 will be described as a double cell having three electrodes 11 and two separators 12. However, this is merely for the convenience of description and does not limit the scope of the present invention.

[0082] The middle electrode reel 111 is a reel on which the middle electrode sheet 1111 is wound, and the middle electrode sheet 1111 is unwound from the middle electrode reel 111. If the unit cell 2 is an A-type dual cell, the middle electrode sheet 1111 is a negative electrode sheet, and if the unit cell 2 is a C-type dual cell, the middle electrode sheet 1111 is a positive electrode sheet. These electrode sheets 1111, 1121, and 1131 can be prepared by coating a slurry of an electrode active material, a conductive agent, and a binder on an electrode current collector, and then drying and pressing the coated electrode current collector.

[0083] The upper diaphragm reel 121 and the lower diaphragm reel 122 are reels on which the diaphragm sheets 1211 and 1221 are wound. In addition, the upper diaphragm sheet 1211 unwound from the upper diaphragm reel 121 is stacked on the upper surface of the middle electrode 1112 formed by cutting the middle electrode sheet 1111, and the lower diaphragm sheet 1221 unwound from the lower diaphragm reel 121 is stacked on the lower surface of the middle electrode 1112.

[0084] The electrode reel may also include: an upper electrode reel 112, from which an upper electrode sheet 1121 to become an upper electrode 1122 to be stacked on the upper surface of an upper diaphragm sheet 1211 is unwound; and a lower electrode reel 113, from which a lower electrode sheet 1131 to become a lower electrode 1132 to be stacked on the lower surface of a lower diaphragm sheet 1221 is unwound.

[0085] The upper electrode reel 112 is a reel on which the upper electrode sheet 1121 is wound, and the upper electrode sheet 1121 is unwound from the upper electrode reel 112. In addition, the lower electrode reel 113 is a reel on which the lower electrode sheet 1131 is wound, and the lower electrode sheet 1131 is unwound from the lower electrode reel 113. If the unit cell 2 is a full cell, the upper electrode 1122 and the lower electrode sheet 1131 have different polarities. In addition, if the unit cell 2 is a double cell, the upper electrode 1122 and the lower electrode sheet 1131 have the same polarity and have a different polarity from the middle electrode 1112. If the unit cell 2 is an A-type dual cell, the middle electrode sheet 1111 is a negative electrode sheet, but the upper electrode sheet 1121 and the lower electrode sheet 1131 are positive electrode sheets, and if the unit cell 2 is a C-type dual cell, the middle electrode sheet 1111 is a positive electrode sheet, but the upper electrode sheet 1121 and the lower electrode sheet 1131 are negative electrode sheets.

[0086] The upper electrode 1122 formed by cutting the upper electrode sheet 1121 is stacked on the upper surface of the upper diaphragm sheet 1211, and the lower electrode 1132 formed by cutting the lower electrode sheet 1131 is stacked on the lower surface of the lower diaphragm sheet 1221. As a result, a stack 20 in which the lower electrode 1132, the lower diaphragm sheet 1221, the middle electrode 1112, the upper diaphragm sheet 1211, and the upper electrode 1122 are sequentially stacked is prepared.

[0087] The stack 20 is formed by stacking a plurality of electrodes 11 on the diaphragm sheets 1211 and 1221 while a plurality of middle electrodes 1112 are separated from each other and arranged in a row in the longitudinal direction of the diaphragm sheets 1211 and 1221. In this case, the upper electrode 1122, the middle electrode 1112, and the lower electrode 1132 may have different intervals from each other, but because the electrodes 11 having the same polarity have the same size, it is preferred that the spacing is always constant. In addition, it is desirable that the upper electrode 1122, the middle electrode 1112, and the lower electrode 1132 are all aligned and arranged so that the middle portions thereof overlap.

[0088] The sealer 14 is disposed between the plurality of electrodes 11 in the stack 20, and applies heat and pressure to at least one of the corners of the electrodes 11 or the edges of the electrodes 11. Therefore, it is possible to prevent the non-adhesive region 22 from being formed on the side 21 of the unit cell 2 including the corners of the electrodes 11, and it is possible to prevent the adhesive force between the electrodes 11 and the separator 12 from being reduced. Subsequently, the sealer 14 will be described in more detail.

[0089] The lamination laminates the entire surface of the stack 20 formed by stacking the electrodes 11 and the separator 12. The term "lamination" means bonding the electrodes 11 and the separator 12 by applying heat and pressure to the stack 20. Figure 4 As illustrated in FIG. 1 , the laminate may include a heater 15 that applies heat and pressure to the entire surface of the stack 20 , and may further include a heating roller 16 that applies pressure to the stack 20 while rotating.

[0090] The heater 15 is composed of an upper heater 151 and a lower heater 152 that can apply heat and pressure to the entire surface of the upper surface and the lower surface of the stack 20, respectively. In the heater 15, the surface in contact with the stack 20 (that is, the lower surface of the upper heater 151 and the upper surface of the lower heater 152) can be formed to be substantially flat. Therefore, heat and pressure can be uniformly applied to the entire surface of the stack 20.

[0091] When the heater 15 applies heat and pressure to the stack 20, the heating roller 16 may apply heat and pressure to the stack 20 while rotating. Generally, the heating roller 16 that applies pressure while rotating applies a higher pressure than the heater 15 that applies pressure with only a flat surface. Therefore, after the heater 15 applies heat and pressure to the stack 20, the heating roller 16 applies heat and pressure greater than the heat and pressure applied by the heater 15 to the stack 20, so that the heat and pressure applied to the stack 20 can be gradually increased. That is, this can prevent the inside of the stack 20 from being damaged due to rapid changes in temperature and pressure.

[0092] When the middle electrode sheet 1111 is first unwound from the middle electrode reel 111, the first cutter 131 cuts the middle electrode sheet 1111 (S301). Then, a plurality of middle electrodes 1112 are formed. In addition, the upper diaphragm sheet 1211 is unwound from the upper diaphragm reel 121 and stacked on the upper surface of the middle electrode 1112, and the lower diaphragm sheet 1221 is unwound from the lower diaphragm reel 122 and stacked on the lower surface of the middle electrode 1112.

[0093] In addition, when the upper electrode sheet 1121 is unwound from the upper electrode reel 112, the second cutter 132 cuts the upper electrode sheet 1121 to form the upper electrode 1122, and when the lower electrode sheet 1131 is unwound from the lower electrode reel 113, the third cutter 133 cuts the lower electrode sheet 1131 to form the lower electrode 1132. The upper electrode 1122 is stacked on the upper surface of the upper diaphragm sheet 1211, and the lower electrode 1132 is stacked on the lower surface of the lower diaphragm sheet 1221. As a result, a stack 20 in which the lower electrode 1132, the lower diaphragm sheet 1221, the middle electrode 1112, the upper diaphragm sheet 1211, and the upper electrode 1122 are sequentially stacked is prepared (S302).

[0094] In the stack 20, at least one of the upper electrode 1122 or the lower electrode 1132 may be omitted, and further, at least one of the upper diaphragm sheet 1211 or the lower diaphragm sheet 1221 may be omitted. Hereinafter, it will be described that in the stack 20, these electrodes 11 and the diaphragm 12 are not omitted. However, this is only for convenience of description and will not limit the scope of the present invention.

[0095] After forming the stack 20, the laminator laminates the stack 20. As described above, the laminator includes the heater 15 and the heating roller 16, and when laminating, after the heater 15 applies heat and pressure to the entire surface of the stack 20, the heating roller 16 can apply heat and pressure to the stack 20 while rotating.

[0096] Figure 5 is a perspective view of a sealer 14 according to an embodiment of the present invention.

[0097] like Figure 5 As illustrated in FIG. 1 , the sealer 14 includes: a first body 141; and a second body 142 extending vertically from the first body 141. Here, the second body 142 may extend from one end of the first body 141, but preferably extends from the middle of the first body 141. That is, the sealer 14 as a whole may have a T-shape. Therefore, with respect to the second body 142 of the sealer 14, one electrode 11 is disposed on one side, and the other electrode 11 is disposed on the other side, so that heat and pressure may be applied to the two electrodes 11 at the same time.

[0098] A heating coil (not shown) is included inside the sealer 14. Therefore, when the sealer 14 comes into contact with the stack 20 and applies pressure to the stack 20, heat generated by the heating coil may also be applied to the stack 20.

[0099] Figure 6 is a plan view illustrating a state in which the sealer 14 according to an embodiment of the present invention applies heat and pressure to the stack 20, and Figure 71 is a side view illustrating a state in which the sealer 14 according to the embodiment of the present invention applies heat and pressure to the stack.

[0100] As described above, the porous coating layer 124 may have a height difference between the side portion 126 and the middle portion 125 of the separator 12. Therefore, the adhesion of the separator 12 is deviated, and thus a non-adhesive region 22 to which the electrode 11 is not adhered or poorly adhered may be formed on the side portion 126 of the separator 12.

[0101] Therefore, according to an embodiment of the present invention, when forming the stack 20, the laminator applies heat and pressure to the stack 20, and then, as shown in FIG. Figure 6 As illustrated in FIG. 3 , the sealer 14 is disposed between the plurality of electrodes 11 in the stack 20 (S303). In addition, the sealer 14 applies heat and pressure to the side 21 of the stack 20 (i.e., to at least one of the corners of the electrode 11 or the edges of the electrode 11). In this case, the sealer 14 is formed in plural and disposed on both sides of the stack 20, so that heat and pressure can be applied to each of the two side 21 of the stack 20. The side 21 is preferably an area each having a length of 1% to 30% (more preferably 5% to 20%) relative to the total length from both ends of the stack 20.

[0102] If the sealer 14 is not used and the heat and pressure applied by the laminate to the entire surface of the stack 20 are simply increased, the middle portion of the stack 20 is subjected to excessive pressure compared to the side portions 21. In turn, the pores of the porous coating layer 124 of the separator 12 are broken to reduce air permeability, whereby the electrode 11 and the separator 12 are not then completely immersed in the electrolyte solution.

[0103] The sealer 14 includes a first body 141 and a second body 142. The first body 141 of the sealer 14 can apply heat and pressure to a first edge 114 outside the stack 20 in the electrode 11, and the second body 142 can apply heat and pressure to a second edge 115 in the electrode 11, the second edge 115 facing another adjacent electrode 11 and intersecting with the first edge 114 to form a corner.

[0104] The first edge 114 is an edge facing the outside of the stack 20 among the multiple edges of the electrode 11. In addition, the first body 141 of the sealer 14 is formed in a direction parallel to the first edge 114. Therefore, when the first body 141 is brought into contact with the stack 20, the first body 141 can be brought into contact with the first edge 114 of the electrode 11, thereby applying heat and pressure to the first edge 114.

[0105] The second edge 115 is an edge that forms a corner of the electrode 11 together with the first edge 114 among the multiple edges of the electrode 11. As described above, on the stack 20, the electrodes 11 are spaced apart from each other and arranged in a row in the longitudinal direction of the diaphragm sheet. Therefore, the electrodes 11 are arranged adjacent to each other, and the second edge 115 faces another adjacent electrode 11. In addition, the second body 142 of the sealer 14 is formed in a direction parallel to the second edge 115. Therefore, when the second body 142 is brought into contact with the stack 20, the second body 142 can be brought into contact with the second edge 115 of the electrode 11, thereby applying heat and pressure to the second edge 115.

[0106] The sealers 14 are formed in plural and may be disposed on both sides of the stack 20. In addition, the sealers 14 may be disposed between the electrodes 11 arranged in a row in the stack 20. Figure 6 As illustrated in FIG. 1 , heat and pressure are simultaneously applied to the plurality of electrodes 11 in the stack 20 , thereby improving the production efficiency of the unit cells 2 .

[0107] As described above, according to the embodiment of the present invention, the plurality of sealers 14 can apply heat and pressure to the corners of the electrode 11. Therefore, the non-adhesive region 22 can be prevented from being formed on the side 21 of the unit cell 2, and the adhesive force between the electrode 11 and the separator 12 can be prevented from being reduced.

[0108] When the sealer 14 applies heat and pressure to the corner of the electrode 11, the first body 141 and the second body 142 may each have a simple rectangular shape. However, the sealer 14 cannot apply heat and pressure to the corner of the electrode 11, but may apply heat and pressure to the edge of the electrode, in particular, only to the edge of the electrode included in the two side portions 21 of the stack 20. In this case, the portion of the sealer 14 corresponding to the corner of the electrode 11 may be recessed. Even in this case, heat and pressure may be applied to the two side portions 21 of the stack 20, so that the formation of the non-bonded area 22 may be prevented.

[0109] After the sealer 14 applies heat and pressure to the side portion 21 of the stack 20 , the fourth cutter 134 cuts the stack 20 , and thus the unit cells 2 may be prepared.

[0110] Figure 8 is a schematic diagram of a unit cell manufacturing apparatus 1 a according to another embodiment of the present invention.

[0111] According to another embodiment of the present invention, Figure 8 That is, neither the heater 15 nor the heating roller 16 is included.

[0112] If a sealer is used, heat and pressure can be applied to both sides 21 of the stack 20, so it is possible to prevent the formation of the non-adhesive region 22 in the side 21 of the unit cell 2. Therefore, according to another embodiment of the present invention, even if the laminate does not laminate the entire surface of the stack 20, the electrode 11 and the separator 12 can be generally uniformly bonded. In addition, the laminate is not included, so the overall process speed can be increased, thereby improving the production efficiency of the unit cell 2.

[0113] Fig. 9 1 is a perspective view of a sealer 14 a according to still another embodiment of the present invention.

[0114] According to another embodiment of the present invention, Fig. 9 As illustrated in the figure, the sealer 14a may also include: a first protrusion 1431, which protrudes downward from the lower surface of the first body 141 and extends in the longitudinal direction of the first body 141; and a second protrusion 1432, which protrudes downward from the lower surface of the second body 142 and extends in the longitudinal direction of the second body 142.

[0115] Fig.10 1 is a side view illustrating a state in which a sealer 14 a according to still another embodiment of the present invention applies heat and pressure to a stack 20 a .

[0116] When the sealer 14a applies heat and pressure to the stack 20a, the first protrusion 1431 can apply heat and pressure to a first region 127 of the diaphragm sheets 1211 and 1221 extending outward from the first edge 114 of the electrode 11, and the second protrusion 1432 can apply heat and pressure to a second region 128 of the diaphragm sheets 1211 and 1221 formed between multiple electrodes 11.

[0117] The first region 127 is a portion of the diaphragm sheets 1211 and 1221 extending outward from the first edge 114 of the electrode 11. Since the first edge 114 of the electrode 11 faces outward, the first region 127 also faces the outside of the stack 20a. In addition, the first protrusion 1431 of the sealer 14a presses the first region 127 of the diaphragm sheets 1211 and 1221, thereby bonding the upper diaphragm sheet 1211 and the lower diaphragm sheet 1221, as shown in FIG. Fig.10 exemplified in .

[0118] The second region 128 is a portion of the diaphragm sheets 1211 and 1221 formed between the plurality of electrodes 11. That is, the region extends from the second edge 115 of the electrode 11. In addition, the second protrusion 1432 of the sealer 14a presses the second region 128 of the diaphragm sheets 1211 and 1221, thereby bonding the upper diaphragm sheet 1211 and the lower diaphragm sheet 1221.

[0119] In order for the first and second protrusions 1431 and 1432 to press the diaphragm sheet 1211 to be easily bonded to the lower diaphragm sheet 1221 , it is preferred that the first and second protrusions 1431 and 1432 are formed thicker than the total thickness of the middle electrode 1112 and the upper electrode 1122 .

[0120] As described above, according to still another embodiment of the present invention, the adhesive force between the separator 12 and the electrode 11 may be improved, and the upper separator sheet 1211 and the lower separator sheet 1221 may be adhered to each other, thereby forming the unit cell 2 more firmly.

[0121] Those skilled in the art will appreciate that the present invention can be performed in other specific forms without changing the technical ideas or basic features. Therefore, the above-mentioned embodiments are understood to be illustrative in all aspects, rather than restrictive. Therefore, the scope of the present invention is limited by the appended claims rather than the exemplary embodiments described above and described herein. Various modifications made within the meaning of the equivalents of the claims of the present invention and within the claims will be considered to be within the scope of the present invention.

[0122] [Description of the symbol]

[0123] 1: Unit battery manufacturing equipment 2: Unit battery

[0124] 11: Electrode 12: Diaphragm

[0125] 14: Sealer 15: Heater

[0126] 16: Roller 20: Stacking piece

[0127] 21: Side of the stack 22: Non-bonded area

[0128] 111: Middle electrode reel 112: Upper electrode reel

[0129] 113: Lower electrode reel 114: First edge

[0130] 115: Second edge 121: Upper diaphragm reel

[0131] 122: Lower diaphragm reel 123: Polymer substrate

[0132] 124: porous coating 125: middle of the diaphragm

[0133] 126: Side of the diaphragm 127: First region

[0134] 128: Second area 131: First cutter

[0135] 132: Second cutter 133: Third cutter

[0136] 134: Fourth cutter 141: First body

[0137] 142: Second body 143: Protrusion

[0138] 1431: first protrusion 1432: second protrusion

[0139] 151: Upper heater 152: Lower heater

[0140] 1111: Middle electrode sheet 1121: Upper electrode sheet

[0141] 1131: Lower electrode sheet 1112: Middle electrode

[0142] 1122: upper electrode 1132: lower electrode

[0143] 1211: Upper diaphragm sheet 1221: Lower diaphragm sheet

Claims

1. A unit cell manufacturing device, the unit cell manufacturing device comprising: an electrode reel from which an electrode sheet to become a plurality of electrodes is unwound; A diaphragm reel, from which the diaphragm sheet stacked with the electrode is unwound; as well as a sealer, in a stack formed by stacking the plurality of electrodes with the diaphragm sheet while the plurality of electrodes are spaced apart from each other and arranged in a row in the longitudinal direction of the diaphragm sheet, the sealer being disposed between the plurality of electrodes and applying heat and pressure to at least one of a corner of the electrode or an edge of the electrode, Wherein, the sealer has a T-shape as a whole.

2. The unit cell manufacturing equipment according to claim 1, wherein: The sealer comprises: The first entity; and A second body vertically extends from the first body.

3. The unit cell manufacturing equipment according to claim 2, wherein: The sealer also includes: a first protrusion that protrudes downward from a lower surface of the first body and is elongated in a longitudinal direction of the first body; and A second protrusion protrudes downward from a lower surface of the second body and is elongated in a longitudinal direction of the second body. 4 . The unit cell manufacturing apparatus according to claim 1 , further comprising a laminating member laminating the stacked members.

5. The unit cell manufacturing equipment according to claim 4, wherein: The laminate includes a heater that applies heat and pressure to the entire surface of the stack.

6. The unit cell manufacturing equipment according to claim 4, wherein: The laminate also includes a heated roller that applies heat and pressure to the stack while rotating.

7. The unit cell manufacturing equipment according to claim 1, wherein: The electrode reels include a middle electrode reel from which a middle electrode sheet to become a plurality of middle electrodes is unwound, and The diaphragm reel comprises: an upper separator reel from which an upper separator sheet stacked on an upper surface of the middle electrode formed by cutting the middle electrode sheet is unwound; and A lower diaphragm reel is used to unwind the lower diaphragm sheet stacked on the lower surface of the middle electrode.

8. The unit cell manufacturing equipment according to claim 7, wherein: The electrode reel further comprises: an upper electrode reel from which an upper electrode sheet to be stacked on an upper surface of the upper separator sheet is unwound; and A lower electrode reel from which a lower electrode sheet to be stacked on the lower surface of the lower separator sheet is unwound.

9. The unit cell manufacturing equipment according to claim 2, wherein: The second body extends from a middle portion of the first body.

10. The unit cell manufacturing equipment according to claim 1, wherein: The sealer includes a heating coil so that when the sealer is in contact with the stack and applies pressure to the stack, heat generated by the heating coil is also applied to the stack.

11. A method for manufacturing a unit battery cell, the method comprising the following steps: cutting the electrode sheet unwound from the electrode reel to form a plurality of electrodes; forming a stack by stacking a plurality of electrodes on a diaphragm sheet while the plurality of electrodes are spaced apart from each other and arranged in a row in a longitudinal direction of the diaphragm sheet unwound from a diaphragm reel; providing a sealer between the plurality of electrodes in the stack; as well as applying heat and pressure to at least one of a corner of the electrode or an edge of the electrode with the sealer, Wherein, the sealer has a T-shape as a whole.

12. The method for manufacturing a unit cell according to claim 11, wherein: The sealer comprises: The first entity; and A second body vertically extends from the first body.

13. The method for manufacturing a unit cell according to claim 12, wherein: When heat and pressure are applied, The first body applies heat and pressure to a first edge among the edges of the electrode, the first edge pointing to the outside of the stack, and The second body applies heat and pressure to a second edge among the edges of the electrode, the second edge facing another adjacent electrode and intersecting the first edge to form a corner.

14. The method for manufacturing a unit cell according to claim 13, wherein: The sealer also includes: a first protrusion that protrudes downward from a lower surface of the first body and is elongated in a longitudinal direction of the first body; and A second protrusion protrudes downward from a lower surface of the second body and is elongated in a longitudinal direction of the second body.

15. The method for manufacturing a unit cell according to claim 14, wherein: When heat and pressure are applied, The first protrusion applies heat and pressure to a first region of the diaphragm sheet extending outward from the first edge of the electrode, and the second protrusion applies heat and pressure to a second region of the diaphragm sheet formed between the plurality of electrodes. 16 . The unit cell manufacturing method according to claim 11 , further comprising laminating the stack after forming the stack and before providing the sealer.

17. The method for manufacturing a unit cell according to claim 16, wherein: The step of laminating the stack further includes: applying heat and pressure to the entire surface of the stack by a heater; and While the heating roller rotates, heat and pressure are applied to the stack by the heating roller.

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