Method for manufacturing high-capacity thick film electrode for battery, electrode manufactured thereby, and battery comprising same

Abstract

The present invention provides a method for manufacturing a high-capacity thick film electrode for a battery, an electrode manufactured thereby, and a battery comprising same. The method for manufacturing an electrode comprises the steps of: mixing slurry including an active material, a binder, a conductive material, and a solvent; homogenizing the slurry while heating; forming a conductive fiber base including a conductive fiber; coating the slurry on the conductive fiber base to a predetermined thickness; and performing phase separation (thermally induced phase separation, TIPS) while cooling the coated slurry.

Description

Method for manufacturing a high-capacity thick-film electrode for a battery, an electrode manufactured thereby, and a battery including the same

[0001] The present invention relates to a method for manufacturing a high-capacity thick-film electrode for a battery, an electrode manufactured thereby, and a battery including the same, and more particularly, to a method for manufacturing a high-capacity thick-film electrode for a battery capable of high-capacity rechargeability, an electrode manufactured thereby, and a battery including the same, which can manufacture an electrode that is difficult to manufacture beyond a certain thickness due to limitations in conductivity by manufacturing it using a thermally induced phase separation process, thereby making it possible to manufacture it relatively thick, thereby increasing the amount of active material while maintaining ionic and electrical conductivity.

[0002] In general, lithium-ion batteries are composed of a current collector coated with electrode materials, an electrolyte, a separator, and an outer shell. Recently, research is being conducted to increase the amount of electrode materials and reduce the current collector in order to implement a high-capacity battery in a limited structure.

[0003] However, when the thickness of the electrode material increases, there is a problem that the ionic conductivity as well as the electrical conductivity do not improve, so an electrode material below a certain thickness must be applied, which is a major technological barrier to the production of high-capacity batteries.

[0004] Accordingly, a technology for a method for manufacturing a high-capacity lithium secondary battery with high charge / discharge efficiency is disclosed through Korean Patent Registration No. 10-2533884, and in particular, a technology for a thick film electrode having uniform and excellent electrical conductivity is disclosed through Korean Patent Publication No. 10-2023-0087677.

[0005] That is, in the above-mentioned Korean Patent Publication No. 10-2023-0087677, a technology is disclosed to minimize problems occurring during solvent vaporization by configuring a slurry with a high solid content and a small amount of solvent during preparation in order to eliminate or minimize the phenomenon of the conductive material and binder being concentrated when the solvent vaporizes in a wet process for thickening the electrode.

[0006] However, a certain amount of solvent is essential for uniform distribution and mixing of the slurry, and the technology for reducing the amount of solvent is also limited, so the manufacturing of thick-film electrodes is still technically difficult to implement.

[0007] Related prior art documents include Korean Patent No. 10-2533884 and Korean Patent Publication No. 10-2023-0087677.

[0008] Accordingly, the technical problem of the present invention is conceived from this point, and the purpose of the present invention is to provide a method for manufacturing a high-capacity thick-film electrode for a high-capacity rechargeable battery, which can increase the amount of active material while maintaining ionic and electrical conductivity by manufacturing the electrode relatively thick, which is difficult to manufacture beyond a certain thickness due to limitations in conductivity, using a thermally induced phase separation process.

[0009] In addition, another object of the present invention is to provide an electrode manufactured by the above manufacturing method.

[0010] In addition, another object of the present invention is to provide a battery including the electrode.

[0011] According to one embodiment of the present invention, a method for manufacturing an electrode includes a step of mixing a slurry including an active material, a binder, a conductive material, and a solvent, a step of heating and homogenizing the slurry, a step of forming a conductive fiber base including conductive fibers, a step of coating the slurry on the conductive fiber base to a predetermined thickness, and a step of cooling and thermally induced phase separation (TIPS) of the coated slurry.

[0012] In one embodiment, in the step of heating and homogenizing the slurry, the slurry may be heated so that the binder is completely dissolved in the solvent.

[0013] In one embodiment, in the step of coating the slurry to a predetermined thickness, the slurry may be coated to a predetermined thickness on the conductive fiber base in consideration of the thickness of the electrode to be manufactured.

[0014] In one embodiment, in the step of cooling the slurry and separating the phases, as the slurry is cooled, the binder is combined with the conductive fibers to form a porous structure.

[0015] In one embodiment, in the step of cooling and phase-separating the slurry, a predetermined pressure can be uniformly applied to the formed slurry.

[0016] In one embodiment, the active material may be a positive electrode active material or a negative electrode active material, the binder may be polyvinylidene fluoride (PVDF), the conductive material may be carbon black, and the solvent may be a carbonate-based electrolyte solvent.

[0017] In one embodiment, the solvent may be a mixture of ethylene carbonate (EC) and polycarbonate (PC).

[0018] In one embodiment, the conductive fiber may be a metal wire having a thickness of tens of micrometers (μm) or less.

[0019] A method for manufacturing the electrode according to another embodiment for realizing the object of the present invention includes the steps of mixing a slurry containing an active material, a binder, a conductive material, and a solvent, heating and homogenizing the slurry, forming a conductive fiber base containing conductive fibers on a mold, coating the slurry on the conductive fiber base to a predetermined thickness, deforming the conductive fiber base and the coated slurry, and removing the mold.

[0020] In one embodiment, the mold may include a space portion that is recessed into a three-dimensional shape.

[0021] In one embodiment, in the step of forming a conductive fiber base on the mold, the conductive fiber base may extend from an upper portion of the space, and an end edge may be positioned on the mold.

[0022] In one embodiment, in the step of deforming the conductive fiber base and the coated slurry, the conductive fiber base and the coated slurry may be deformed by applying pressure.

[0023] In one embodiment, the conductive fiber base and the coated slurry can be deformed using a press mold including a protrusion inserted into the space.

[0024] In one embodiment, in the step of deforming the conductive fiber base and the coated slurry, the coated slurry may be cooled and phase separated (thermally induced phase separation, TIPS).

[0025] In one embodiment, the coated slurry may be cooled by a separate cooling unit or a cooling unit provided within the pressurized mold. In one embodiment, the conductive fiber base and the coated slurry may be deformed and cooled under a predetermined pressure while the pressurized mold itself is cooled.

[0026] An electrode according to one embodiment for realizing another object of the present invention described above is manufactured using the above electrode manufacturing method and has a three-dimensional shape.

[0027] In one embodiment, the electrode may have any one of a hemispherical shape, a conical shape, a donut shape, a polygonal block shape, and a polygonal pyramid shape.

[0028] According to one embodiment of the present invention for realizing another object of the present invention, a battery is manufactured by the above-described electrode manufacturing method and includes a positive electrode including a positive active material, a negative electrode manufactured by the above-described electrode manufacturing method and including a negative active material, a separator interposed between the positive electrode and the negative electrode, an upper cover covering the outside of the positive electrode, and a lower cover covering the outside of the negative electrode.

[0029] In one embodiment, the positive electrode, the negative electrode, the separator, the upper cover, and the lower cover may be laminated to form a three-dimensional shape.

[0030] According to embodiments of the present invention, in the manufacture of an electrode, an active material, a conductive material, and a binder are combined through so-called phase separation (thermally induced phase separation, TIPS) of a slurry coated on a conductive fiber base, thereby forming an electrode layer bonded to the conductive fiber to form a porous structure, and the conductive fiber functions as a current collector. Accordingly, it is possible to manufacture an electrode having relatively high mechanical strength, ionic conductivity, and electrical conductivity.

[0031] In particular, since the conductive fibers are combined in a form that is embedded within the slurry, a structure is created in which the current collector is uniformly distributed throughout the electrode, and thus, even when formed into a thick-film electrode having a relatively thick thickness, the electrochemical properties of the electrode can be excellently maintained. Furthermore, since a constant electric capacity can be maintained regardless of repeated bending deformation, electrical stability can also be improved.

[0032] In contrast, in the manufacture of the above electrode, a three-dimensional electrode having a porous structure with conductive fibers embedded therein can be manufactured using a mold, thereby diversifying the usability of the electrode into various structures while maintaining the mechanical stability of the three-dimensional shape.

[0033] That is, by manufacturing the mold to include a space portion of a desired three-dimensional shape, and performing phase separation by changing the shape of the slurry and the conductive fiber using a pressurized mold while the slurry is coated on the basis of the conductive fiber, an electrode having mechanical stability of the three-dimensional shape can be easily manufactured.

[0034] Thus, the electrode manufactured in this way has the electrical, mechanical, and chemical properties of the previously described flat-shaped thick-film electrode, while at the same time being usable as a variety of three-dimensional structure electrodes.

[0035] In particular, the electrode can be manufactured into a battery using other components having the same shape and structure, thereby diversifying the usability of the battery into a three-dimensional structure having excellent electrical, mechanical, and chemical properties.

[0036] Figure 1 is a flow chart illustrating a method for manufacturing a high-capacity thick-film electrode for a battery according to one embodiment of the present invention.

[0037] Figures 2a to 2d are process diagrams illustrating a method for manufacturing the electrode of Figure 1.

[0038] Figure 3 is an image illustrating an electrode manufactured using the manufacturing method of the electrode of Figure 1.

[0039] Figures 4a and 4b are images showing the flow of ions and charges in the electrode according to the prior art and the electrode of Figure 1, respectively.

[0040] FIG. 5a is a graph showing a Nyquist plot after performing three cycles of charge and discharge for each electrode of FIG. 4a and FIG. 4b, and FIG. 5b is a graph showing peak current versus the square root of the scan rate for each electrode of FIG. 4a and FIG. 4b.

[0041] FIG. 6a is an image illustrating an electrode according to a prior art and an electrode of FIG. 1, FIG. 6b is a graph showing stress / strain tensile strength for each electrode of FIG. 6a, and FIG. 6c is a graph showing electrical resistance according to thickness for each electrode of FIG. 6a.

[0042] Fig. 7 is a graph showing the charge / discharge profile of a battery to which the electrode of Fig. 4b is applied.

[0043] Figure 8 is a flow chart illustrating a method for manufacturing a high-capacity thick-film electrode for a battery according to another embodiment of the present invention.

[0044] Figures 9a to 9d are process diagrams illustrating a method for manufacturing the electrode of Figure 8.

[0045] Figures 10a and 10b are images illustrating electrodes manufactured using the method for manufacturing the electrode of Figure 8.

[0046] Fig. 11 is an exploded perspective view showing a battery including an electrode manufactured using the method for manufacturing the electrode of Fig. 8.

[0047] <Explanation of symbols>

[0048] 10: Active material 20: Binder

[0049] 30: Challenger 40: Solvent

[0050] 100: Slurry 101: Homogeneous slurry

[0051] 110: Conductive fiber base 111: Conductive fiber

[0052] 200, 201, 202, 203: Electrode 300: Mold

[0053] 301, 302: Space 310: Pressurized mold

[0054] 400: Battery 410: Separator

[0055] 420: Lower cover 430: Upper cover

[0056] The present invention is susceptible to various modifications and takes various forms, and thus embodiments are described in detail herein. However, this is not intended to limit the present invention to a specific disclosed form, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. Similar reference numerals have been used to designate similar components throughout the description of each drawing. While terms such as "first," "second," etc. may be used to describe various components, these components should not be limited by these terms.

[0057] The above terms are used solely to distinguish one component from another. The terms used in this application are used solely to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0058] In this application, it should be understood that terms such as “comprise” or “consist of” are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0059] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0060] Hereinafter, with reference to the attached drawings, a preferred embodiment of the present invention will be described in more detail.

[0061] Fig. 1 is a flowchart illustrating a method for manufacturing a high-capacity thick-film electrode for a battery according to one embodiment of the present invention. Figs. 2a to 2d are process diagrams illustrating a method for manufacturing the electrode of Fig. 1.

[0062] Referring to FIGS. 1 and 2a, in the method for manufacturing the high-capacity thick-film electrode for the battery according to the present embodiment (hereinafter, the electrode manufacturing method), first, a slurry (slurry, 100) is mixed (step S10). That is, in the step of mixing the slurry (100), an active material (active material, 10) such as a positive electrode active material or a negative electrode active material, a binder (20), a conductive agent (30), and a solvent (40) are mixed together in the form of a slurry.

[0063] At this time, the active material (10) may be a positive electrode active material or a negative electrode active material depending on whether the electrode being manufactured is a positive electrode or a negative electrode. In addition, the binder (20) is an adhesive material that induces the active material (10) and the conductive material (30) to adhere well to a current collector, etc., and may be, for example, polyvinylidene fluoride (PVDF), but is not limited thereto.

[0064] The above-mentioned conductive material (30) may be a conductive material, for example, carbon black, but the material is not limited thereto.

[0065] In addition, the solvent (40) is for uniform mixing of the active material, binder, and conductive agent, and may be a carbonate-based solvent. For example, the solvent (40) may be a mixed solvent of ethylene carbonate (EC) and polycarbonate (PC), but is not limited thereto.

[0066] As described above, after the active material, binder, conductive agent, and solvent are mixed together to create a slurry (100) (step S10), referring to FIGS. 1 and 2b, the slurry (100) is heated and homogenized (step S20). This homogenization step (step S20) can be performed, for example, by heating the binder (20) so that it is completely dissolved in the solvent (40).

[0067] In this way, in order for the binder (20) to be completely dissolved in the solvent (40), heating may be performed at a temperature higher than the melting point of the binder (20). At this time, the method of heating the binder (20) to a temperature higher than the melting point is not limited, and various conventional heating methods may be performed.

[0068] That is, as the slurry (100) is heated and the binder (20) is completely dissolved in the solvent (40), the binder (20) is homogenized together with the active material, conductive material, and solvent into a slurry (101) form as shown in FIG. 2b. That is, it is manufactured as a homogenized slurry (101).

[0069] After this, referring to FIG. 1 and FIG. 2c, a conductive fiber base (110) including conductive fibers is formed to a predetermined area (step S30).

[0070] At this time, the conductive fiber may be a metal wire such as a SUS fiber having a thickness of tens of micrometers (μm) or less, and these unit conductive fibers are entangled in a complex manner to form the conductive fiber base (110).

[0071] In addition, the area of ​​the conductive fiber base (110) can be formed in various ways in consideration of the area of ​​the final electrode to be manufactured, and the range is not limited.

[0072] As described above, after the conductive fiber base (110) is manufactured separately, referring to FIGS. 1 and 2c, the homogenized slurry (101) is coated on the conductive fiber base (110) to a predetermined thickness (step S40).

[0073] In the coating step of the above slurry (101), the thickness of the coating of the slurry (101) can be controlled in various ways.

[0074] That is, in the case of the present embodiment, as described below, as the slurry (101) is coated on the conductive fiber base (110), the conductive fiber included in the conductive fiber base (110) has a structure in which it is embedded and bonded with the slurry (101), and accordingly, the conductive fiber that serves as a current collector can be uniformly bonded to the slurry (101) to be coated.

[0075] Therefore, even if the thickness of the electrode is formed thickly by coating the slurry (101) thickly, the electrochemical characteristics of the electrode can be stably maintained.

[0076] Accordingly, it is possible to manufacture an electrode by coating the slurry (101) relatively thickly, and the thickness of the slurry (101) can be formed by varying the thickness in various ways in consideration of the various thicknesses of the electrode to be manufactured.

[0077] Thereafter, referring to FIG. 1 and FIG. 2d, the slurry (101) coated on the conductive fiber base (110) to a predetermined thickness is cooled and phase separated (thermally induced phase separation, TIPS), thereby finally manufacturing an electrode (200) (step S50).

[0078] At this time, in the case of the phase separation, cooling is performed to a temperature below a predetermined temperature for the slurry (101), and the binder (20), which was slurried by heating in the previous homogenization step (step S20) so that the binder (20) is completely dissolved in the solvent (40), is solidified through the cooling.

[0079] In performing the cooling of the above slurry (101), for example, solidification of the binder (20) can be performed by cooling below the melting point of the binder (20). Furthermore, as in the heating process, the method of the cooling process is not limited, and various conventional cooling processes can be applied.

[0080] Accordingly, in the process of the binder (20) being cooled and solidified, the binder (20) is embedded and combined with the conductive fiber (111, see FIG. 3) included in the conductive fiber base (110), and has a porous structure.

[0081] The state in which the above binder (20) has a porous structure and is embedded and bonded with the conductive fiber (111) is as shown in FIG. 3.

[0082] That is, FIG. 3 is an image illustrating an electrode manufactured using the manufacturing method of the electrode of FIG. 1, and as illustrated in FIG. 3, the electrode (200) has an overall porous structure, and the conductive fibers (111) are distributed within the porous structure. At this time, the distribution of the conductive fibers (111) may have an arbitrary distribution, but may be distributed throughout the electrode (200) with a predetermined degree of uniformity.

[0083] As described above, by cooling and solidifying the binder (20) through the phase separation process, it is possible to manufacture an electrode (200) having a porous structure in which conductive fibers (111) are distributed throughout the entire interior, and in this electrode (200), conductive fibers (111) that serve as a current collector are distributed throughout the interior of the electrode (200).

[0084] Figures 4a and 4b are images showing the flow of ions and charges in the electrode according to the prior art and the electrode of Figure 1, respectively.

[0085] That is, as in Fig. 4a, in the case of the electrode (2) according to the conventional technology, the current collector (1) is extended in a film shape, and the electrode body is simply coated on the current collector (1) to form the electrode (2). That is, in the conventional electrode (2), the electrode body has a structure in which it is coated on the upper surface of the current collector (1) while having a predetermined thickness.

[0086] In contrast, as shown in FIG. 4b, in the case of the electrode (200) according to the present embodiment, there is no separate current collector formed on the base layer, and the conductive fiber base (110) is combined and distributed into the interior of the slurry (101) through embedded bonding with the slurry through a phase separation step, so that the conductive fiber (111) is distributed at any location inside the electrode (200).

[0087] That is, the electrode body and the current collector do not have a structure in which they are coated on one side, but rather have a structure in which the conductive fiber base (110) is distributed throughout the interior of the slurry (101).

[0088] In addition, the conductive fibers (111) distributed in this manner serve as a current collector. Accordingly, it can be confirmed that in the electrode (200) according to the present embodiment, a structure is formed in which internal structures are more complexly connected and distributed.

[0089] FIG. 5a is a graph showing a Nyquist plot after performing three cycles of charge and discharge for each electrode of FIG. 4a and FIG. 4b, and FIG. 5b is a graph showing peak current versus the square root of the scan rate for each electrode of FIG. 4a and FIG. 4b.

[0090] Meanwhile, in the graphs below including FIGS. 5a and 5b, the electrode (2) according to the prior art in FIG. 4a is indicated as Foil, and the electrode (200) according to the present embodiment in FIG. 4b is indicated as SS fiber.

[0091] Referring to Fig. 5a, as can be seen from the results of cyclic charging and discharging of the electrode (2) according to the prior art of Fig. 4a, the charge transfer resistance is relatively high, at about 200 to 250Ω.

[0092] In contrast, as confirmed in the results of the periodic performance of charge and discharge for the electrode (200) according to the present embodiment of FIG. 4b, it is confirmed that the charge transfer resistance is relatively low at about 10Ω.

[0093] That is, it can be confirmed that the charge transfer resistance in the electrode (200) according to the present embodiment is relatively very low, and through this, it can be confirmed that the ion conductivity of the electrode (200) according to the present embodiment is relatively very high compared to the prior art.

[0094] Meanwhile, referring to FIG. 5b, in the case of peak current according to the square root of the scan rate, it can be confirmed that the increase in peak current according to the square root of the scan rate is greater in the case of the electrode (200) according to the present embodiment than in the electrode (2) according to the prior art.

[0095] Through this, it can be confirmed that in the case of the electrode (200) according to the present embodiment, diffusion is performed much more effectively, and through this, it can be confirmed that the ionic conductivity is relatively very high compared to the prior art.

[0096] FIG. 6a is an image illustrating an electrode according to a prior art and an electrode of FIG. 1, FIG. 6b is a graph showing stress / strain tensile strength for each electrode of FIG. 6a, and FIG. 6c is a graph showing electrical resistance according to thickness for each electrode of FIG. 6a.

[0097] Referring to Fig. 6a, the electrode (2) according to the prior art in Fig. 4a as described above has a structure in which an electrode body is formed on a film or foil as a current collector, as shown, and has a structure in which the electrode layer is peeled, broken, or cut according to the elongation of the electrode plate.

[0098] In contrast, the electrode manufactured through the electrode manufacturing method of FIG. 1 according to the present embodiment, i.e., the electrode (200) in FIG. 4b, has a structure in which the conductive fibers are embedded and bonded to the electrode body as a whole, and therefore is relatively not interrupted or cut according to the elongation of the electrode.

[0099] That is, even when the same force is applied, it can be confirmed that relatively less breakage, peeling, or cutting occurs in the case of the electrode (200) according to the present embodiment.

[0100] In addition, as shown in Fig. 6b, in the stress-strain diagram, in the electrode (2, Foil electrode) according to the prior art of Fig. 4a, it can be confirmed that as the strain increases, the stress increases rapidly and the electrode (2) is cut. In contrast, in the electrode (200, SS fiber electrode) according to the present embodiment of Fig. 4b, it can be confirmed that even if the strain increases, the stress does not increase beyond a certain level, and the cut is limited and a relatively stable state is maintained.

[0101] As described above, in the case of the electrode (200) according to the present embodiment, it can be confirmed that the mechanical stability is superior compared to the electrode (2) according to the prior art.

[0102] Furthermore, referring to Fig. 6c, it can be confirmed that in the case of the electrode (200, SS fiber) according to the present embodiment, the resistance is maintained at a constant level even if the thickness increases. However, in the electrode (2, Foil) of the prior art, the resistance also increases simultaneously as the thickness increases, and it can be confirmed that this tendency of increasing resistance according to the increase in thickness is different from the tendency of the electrode (200) of the present embodiment.

[0103] This means that even if the thickness of the electrode (200) according to the present embodiment is formed to be 500 μm or thicker as exemplified, the electrical resistance is maintained very small, and thus it can be confirmed that the electrical conductivity is maintained high.

[0104] Therefore, as described above, in the manufacture of the electrode (200) according to the present embodiment, it can be confirmed that it is possible to manufacture a relatively thick film electrode by performing the coating process (step S40) of the slurry so as to have a sufficiently thick thickness.

[0105] Fig. 7 is a graph showing the charge / discharge profile of a battery to which the electrode of Fig. 4b is applied.

[0106] That is, Fig. 7 shows the charge / discharge state of the electrode (200) according to the present embodiment after performing approximately 2,000 repeated bendings, compared to the charge / discharge state in the initial state.

[0107] As confirmed through Fig. 7, even if a considerable number of bendings, approximately 2,000 times, are repeatedly performed, it can be confirmed that the charge / discharge state of the electrode (200) is maintained very similar to the charge / discharge state in the initial state. In this case, the number of bendings, approximately 2,000 times, is exemplary, and the number of repeated bendings can be varied, and even in such various cases, a charge / discharge state similar to the initial state can be exhibited.

[0108] Accordingly, it can be confirmed that the electrode (200) in this embodiment maintains stable charging and discharging even after repeated bending, and that not only mechanical stability but also electrical characteristics are maintained.

[0109] As described above, in the case of the electrode (200) manufactured through the electrode manufacturing method of FIG. 1 according to the present embodiment, it can be confirmed that even if it is manufactured as a thick-film electrode with a relatively thick thickness, not only mechanical stability but also electrochemical characteristics are stably maintained.

[0110] Fig. 8 is a flowchart illustrating a method for manufacturing a high-capacity thick-film electrode for a battery according to another embodiment of the present invention. Figs. 9a to 9d are process diagrams illustrating a method for manufacturing the electrode of Fig. 8.

[0111] First, referring to Fig. 8, in the method for manufacturing the electrode according to the present embodiment, a slurry (100) is mixed (step S11). This mixing step (step S11) of the slurry (100) is substantially the same as the mixing step (step S10) of the slurry described with reference to Fig. 1.

[0112] That is, an active material (10), such as a positive electrode active material or a negative electrode active material, a binder (20), a conductive material (30), and a solvent (40) are mixed together in a slurry form, and the types of each material are as described above.

[0113] Thereafter, referring to FIG. 8, the mixed slurry (100) is heated and homogenized (step S21), and this homogenization step (step S21) is also substantially the same as the homogenization step (step S20) in FIG. 1.

[0114] That is, in the homogenization step, as described above, the binder (20) is heated so that it is completely dissolved in the solvent (40), and the binder (20) is homogenized together with the active material, conductive material, and solvent in the form of a slurry (101).

[0115] After this, referring to FIGS. 8 and 9a, in a state where a mold (300) of a predetermined shape is prepared, a conductive fiber base (110) including conductive fibers is formed on the mold (300) (step S31).

[0116] At this time, the conductive fiber base (110) is substantially the same as the conductive fiber base described with reference to Fig. 1. That is, the conductive fiber may be a metal wire such as a SUS fiber having a thickness of tens of micrometers (μm) or less, and these unit conductive fibers are complexly entangled to form the conductive fiber base (110).

[0117] In the present embodiment, the conductive fiber base (110) is formed to have a predetermined area on the mold (300). For example, as shown in the drawing, if the mold (300) has a three-dimensional insertion structure formed to have a predetermined space (301) inserted therein, the conductive fiber base (110) may be formed to extend along the upper portion of the space (301) so as to be fixed to the edge of the mold (300).

[0118] That is, if the mold (300) has, for example, a hemispherical shape, the conductive fiber base (110) can be extended on the upper part of the three-dimensional hemispherical shape formed by the mold (300) while being fixed along the edge of the cylindrical shape of the mold (300).

[0119] Meanwhile, the shape of the mold (300) is not limited to a concave hemispherical shape as shown, and may have a three-dimensional shape that is concave in various shapes such as a cone shape, a donut shape, a polygonal block shape, a polygonal pyramid shape, etc.

[0120] Furthermore, in addition to the single defined shape exemplified above, it can be formed into a complex three-dimensional shape in which concave and convex portions are formed in various ways, and the shape is not limited.

[0121] At this time, the conductive fiber base (110) is fixed to the edge of the mold (300), and the edge area of ​​the mold (300) can be formed to include a sufficient area to stably fix the conductive fiber base (110).

[0122] After this, referring to FIG. 8 and FIG. 9a, the slurry (101) is coated on the upper surface of the conductive fiber base (110) formed on the mold (300) (step S41).

[0123] In the coating step (step S41) of the slurry (101), the thickness of the slurry (101) to be coated can be controlled in various ways, and in particular, as described above, even if the electrode is formed thick by coating the slurry (101) relatively thickly, the electrochemical characteristics of the electrode can be sufficiently stably maintained.

[0124] Therefore, it is possible to manufacture an electrode by coating the slurry (101) relatively thickly, and the thickness of the slurry (101) can be formed by varying the thickness in various ways in consideration of the various thicknesses of the electrode to be manufactured.

[0125] After this, referring to FIGS. 8 and 9b, the conductive fiber base (110) and the slurry (101) coated thereon are pressed using a pressurized mold (310) to change the shape (step S51).

[0126] At this time, the shape of the pressurized mold (310) can be manufactured by considering the shape of the mold (300). For example, as illustrated, if the mold (300) has a concave hemispherical shape, the pressurized mold (310) can be formed so that the convexly protruding protrusion (311) has a hemispherical shape.

[0127] In this case, the degree of protrusion of the protrusion (311) can be designed by considering the shape of the concavely inserted space (300) and the thickness of the slurry (101) to be coated, and it is sufficient if it has a strength that can vary the shape of the slurry (101) and the conductive fiber base (110).

[0128] It is obvious that the pressurization of the pressurized mold (310) can be performed by applying a predetermined pressure, and by the pressurization of the pressurized mold (310), as shown in FIG. 9b, the protrusion (311) is inserted into the space (301), and the shape of the slurry (101) and the conductive fiber base (110) is changed to the same shape as the shape of the protrusion (311) and the space (301).

[0129] Meanwhile, as previously explained, if the space portion (301) is formed to be inserted into various three-dimensional shapes, it is obvious that the protrusion portion (311) should be formed to protrude into a corresponding shape. Furthermore, if the space portion (301) is formed to include both inserted shapes and protruded shapes, it is also obvious that the protrusion portion (311) should be formed to include both protruded shapes and inserted shapes.

[0130] In addition, in the pressurizing step (step S51), thermally induced phase separation (TIPS) that cools the slurry (101) is performed simultaneously, through which an electrode (201) having a predetermined shape is finally manufactured.

[0131] This phase separation process is performed by, for example, cooling below the melting point of the binder (20), as described above, so that the binder (20), which was slurried by heating above the melting point in the previous homogenization step (step S21), is solidified through the cooling.

[0132] Meanwhile, in the process of the binder (20) being cooled and solidified, the binder (20) is embedded and combined with the conductive fiber (111) included in the conductive fiber base (110), and has a porous structure.

[0133] Furthermore, since this phase separation process is performed simultaneously with the shape changing process by pressurization, the shape of the electrode (201) as a whole is changed according to the shape of the space (301) and the protrusion (311), and at the same time, the conductive fiber (111) and the binder (20) are embedded and bonded to form a porous structure.

[0134] In order to perform the above pressurization process and the cooling process for phase separation simultaneously, the pressurization mold (310) can pressurize the shape of the slurry (101) and the conductive fiber base (110) with a predetermined pressure, and perform cooling on the slurry (101) and the conductive fiber base (110) through a separate cooling unit.

[0135] Alternatively, the pressing process and the cooling process for phase separation may be performed simultaneously through a process of pressing the slurry (101) and the conductive fiber base (110) into a shape at a predetermined pressure while a predetermined cooling unit is provided inside the pressing mold (310) or the pressing mold (310) itself is cooled.

[0136] After this, referring to FIGS. 8 and 9c, the pressurized mold (310) is removed to the outside (step S61), and accordingly, the electrode (201) is manufactured in which the shape of the space portion (301) and the protrusion portion (311) is reflected, as in FIG. 9d.

[0137] Meanwhile, in the case of the electrode (201), only the conductive fiber base (110) remains in the portion where the slurry (101) is not coated, and the conductive fiber base (110) remaining in this way remains in a form that protrudes partially at the end of the electrode (201).

[0138] In this case, the remaining conductive fiber base (110) may be selectively removed. The removal of the remaining conductive fiber base (110) may be performed through a separate cutting unit, but is not limited thereto.

[0139] The electrode (201) manufactured in this way has a hemispherical shape with a predetermined thickness, as described above, such as the shape of the space portion (301) and the protrusion portion (311), and the inside of the electrode (201) has a structure as described with reference to FIGS. 3 and 4b.

[0140] That is, through this embodiment, it is possible to manufacture an electrode (201) having a porous structure in which conductive fibers (111) are distributed while having a predetermined three-dimensional shape, and in this electrode (201), conductive fibers (111) that serve as a current collector are distributed throughout the entire interior of the electrode (201).

[0141] At this time, by designing the shapes of the mold (300) and the pressurizing mold (310), electrodes of the required three-dimensional shape can be manufactured, thereby enabling the manufacture of various electrodes as required through an easy process. Hereinafter, examples of electrodes of various shapes will be described.

[0142] Figures 10a and 10b are images illustrating electrodes manufactured using the method for manufacturing the electrode of Figure 8.

[0143] Referring to FIG. 10a, when manufacturing an electrode using the electrode manufacturing method of FIG. 8, the space portion (301) of the mold (300) can be formed into an embedded pyramid shape, i.e., a square pyramid shape, and similarly, the protruding portion (311) of the pressurized mold (310) can be formed into a corresponding protruding pyramid shape, i.e., a square pyramid shape.

[0144] Through this, as shown, an electrode (202) having a pyramid shape can be formed.

[0145] Likewise, referring to FIG. 10b, when manufacturing an electrode using the electrode manufacturing method of FIG. 8, the space (301) of the mold (300) can be formed into a donut shape, and similarly, the protrusion (311) of the pressurized mold (310) can also be formed into a corresponding protruding donut shape.

[0146] Through this, as shown, an electrode (203) having a donut shape can be formed.

[0147] Fig. 11 is an exploded perspective view showing a battery including an electrode manufactured using the method for manufacturing the electrode of Fig. 8.

[0148] Referring to FIG. 11, the battery (400) includes an electrode (201) manufactured through the electrode manufacturing method described with reference to FIG. 8.

[0149] Specifically, the battery (400) includes a positive electrode (201(a)), a negative electrode (201(b)), a separator (410), a lower cover (420), and an upper cover (430), and has an overall hemispherical shape.

[0150] At this time, the positive electrode (201(a)) is an electrode manufactured using the electrode manufacturing method of FIG. 8, and can be manufactured as a positive electrode by manufacturing a slurry to include a positive electrode active material.

[0151] Likewise, the negative electrode (201(b)) is an electrode manufactured using the electrode manufacturing method of FIG. 8, and can be manufactured as a negative electrode by manufacturing a slurry containing a negative electrode active material.

[0152] Additionally, both of these positive and negative electrodes are manufactured in a three-dimensional hemispherical shape, more precisely, in a hemispherical shell shape with a space formed inside.

[0153] In addition, since both the positive and negative electrodes are manufactured in a hemispherical shell shape, the separator (410), as well as the lower cover (420) and the upper cover (430), are manufactured in the same hemispherical shell shape.

[0154] Accordingly, the lower cover (420), the negative electrode (201(b)), the separator (410), the positive electrode (201(a)), and the upper cover (430) can be sequentially laminated to produce the battery (400).

[0155] In addition, the battery (400) manufactured in this way supplies power stably, as shown in Fig. 11.

[0156] Furthermore, although the battery (400) is exemplified as having a hemispherical shape through FIG. 11, as previously explained, since the shape of the electrode can be manufactured into various three-dimensional shapes, by manufacturing the separator (410), the lower cover (420), and the upper cover (430) into the same three-dimensional shape, the battery (400) can be manufactured into various three-dimensional shapes.

[0157] According to the embodiments of the present invention as described above, in the manufacture of an electrode, an active material, a conductive material, and a binder are combined through so-called phase separation (thermally induced phase separation, TIPS) with respect to a slurry coated on a conductive fiber base, so that an electrode layer is combined with the conductive fiber to form a porous structure, and an electrode in which the conductive fiber functions as a current collector is manufactured. Accordingly, it is possible to manufacture an electrode having relatively high mechanical strength, ionic conductivity, and electrical conductivity.

[0158] In particular, since the conductive fibers are combined in a form that is embedded within the slurry, a structure is created in which the current collector is uniformly distributed throughout the electrode, and thus, even when formed into a thick-film electrode having a relatively thick thickness, the electrochemical properties of the electrode can be excellently maintained. Furthermore, since a constant electric capacity can be maintained regardless of repeated bending deformation, electrical stability can also be improved.

[0159] In contrast, in the manufacture of the above electrode, a three-dimensional electrode having a porous structure with conductive fibers embedded therein can be manufactured using a mold, thereby diversifying the usability of the electrode into various structures while maintaining the mechanical stability of the three-dimensional shape.

[0160] That is, by manufacturing the mold to include a space portion of a desired three-dimensional shape, and performing phase separation by changing the shape of the slurry and the conductive fiber using a pressurized mold while the slurry is coated on the basis of the conductive fiber, an electrode having mechanical stability of the three-dimensional shape can be easily manufactured.

[0161] Thus, the electrode manufactured in this way has the electrical, mechanical, and chemical properties of the previously described flat-shaped thick-film electrode, while at the same time being usable as a variety of three-dimensional structure electrodes.

[0162] In particular, the electrode can be manufactured into a battery using other components having the same shape and structure, thereby diversifying the usability of the battery into a three-dimensional structure having excellent electrical, mechanical, and chemical properties.

[0163] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. A step of mixing a slurry containing an active material, a binder, a conductive agent, and a solvent; A step of heating and homogenizing the above slurry; A step of forming a conductive fiber base including conductive fibers; A step of coating the slurry on the conductive fiber base to a predetermined thickness; and A method for manufacturing an electrode, comprising a step of cooling the coated slurry and performing phase separation (thermally induced phase separation, TIPS).

2. In the step of heating and homogenizing the slurry in paragraph 1, A method for manufacturing an electrode, characterized in that the binder is heated so that it is completely dissolved in the solvent.

3. In the step of coating the slurry to a predetermined thickness in the first paragraph, A method for manufacturing an electrode, characterized in that the slurry is coated on the conductive fiber base to a predetermined thickness, taking into account the thickness of the electrode to be manufactured.

4. In the step of cooling and separating the coated slurry in the first paragraph, A method for manufacturing an electrode, characterized in that as the slurry is cooled, the binder is combined with the conductive fibers and a porous structure is formed.

5. In the step of cooling and separating the slurry in the fourth paragraph, A method for manufacturing an electrode, characterized in that a predetermined pressure is uniformly applied to the formed slurry.

6. In paragraph 1, The above active material is a positive electrode active material or a negative electrode active material, The above binder is polyvinylidene fluoride (PVDF), The above challenge material is carbon black, A method for manufacturing an electrode, characterized in that the solvent is a carbonate-based electrolyte solvent.

7. In paragraph 6, the solvent is A method for manufacturing an electrode characterized by a mixture of ethylene carbonate (EC) and polycarbonate (PC).

8. In the first paragraph, the conductive fiber, A method for manufacturing an electrode, characterized in that the electrode is a metal wire having a thickness of tens of micrometers (μm) or less.

9. A step of mixing a slurry containing an active material, a binder, a conductive agent, and a solvent; A step of heating and homogenizing the above slurry; A step of forming a conductive fiber base including conductive fibers on a mold; A step of coating the slurry on the conductive fiber base to a predetermined thickness; A step of deforming the conductive fiber base and the coated slurry; and A method for manufacturing an electrode, comprising the step of removing the mold.

10. In the 9th paragraph, the mold, A method for manufacturing an electrode, characterized in that it includes a space portion embedded in a three-dimensional shape.

11. In the step of forming a conductive fiber base on the mold in the 10th paragraph, A method for manufacturing an electrode, characterized in that the conductive fiber base extends from the upper portion of the space and the end edge is positioned in the mold.

12. In the step of transforming the conductive fiber base and the coated slurry in the 10th paragraph, A method for manufacturing an electrode, characterized in that the conductive fiber base and the coated slurry are deformed by applying pressure.

13. In the 12th paragraph, the conductive fiber base and the coated slurry, A method for manufacturing an electrode characterized in that it is deformed using a pressure mold including a protrusion inserted into the above space.

14. In the step of transforming the conductive fiber base and the coated slurry in the 13th paragraph, A method for manufacturing an electrode, characterized in that the coated slurry is cooled and phase separated (thermally induced phase separation, TIPS).

15. In the 13th paragraph, the coated slurry, A method for manufacturing an electrode, characterized in that it is cooled by a separate cooling unit or a cooling unit provided inside the pressurized mold.

16. In paragraph 13, A method for manufacturing an electrode, characterized in that the conductive fiber base and the coated slurry are deformed and cooled at a predetermined pressure while the pressurized mold itself is cooled.

17. An electrode manufactured by the method of manufacturing an electrode according to any one of claims 9 to 16, An electrode characterized in that the electrode has a three-dimensional shape.

18. In the 17th paragraph, the electrode, An electrode characterized by having any one of a hemispherical shape, a conical shape, a donut shape, a polygonal block shape, and a polygonal pyramid shape.

19. A positive electrode manufactured by the method for manufacturing an electrode according to any one of claims 9 to 16, and including a positive electrode active material; A negative electrode manufactured by the method for manufacturing an electrode according to any one of claims 9 to 16, and including a negative electrode active material; A separator interposed between the positive electrode and the negative electrode; an upper cover covering the outside of the positive electrode; and A battery comprising a lower cover covering the outside of the negative electrode.

20. In paragraph 19, A battery characterized in that the positive electrode, the negative electrode, the separator, the upper cover, and the lower cover are laminated to form a three-dimensional shape.

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