Rechargeable battery manufacturing equipment and method for manufacturing rechargeable batteries using the same

Abstract

According to an exemplary embodiment, a method for manufacturing a secondary battery is provided. The method includes the steps of: applying a first electrode slurry to a current collector sheet so that a plurality of active guide lanes are formed on the current collector sheet; applying a second electrode slurry to the current collector sheet so that electrode slurry lanes are formed between the plurality of active guide lanes; and drying the active guide lanes and the electrode slurry lanes so that an active material layer is formed, wherein the solid content of the first electrode slurry is different from the solid content of the second electrode slurry.

Description

[Technical Field]

[0001] The present invention relates to a secondary battery manufacturing apparatus and a method for manufacturing a secondary battery using the same. This application claims priority based on Korean Application No. 10-2025-0046622, filed on April 10, 2025, which is herein by reference in its entirety. Korean Application No. 10-2025-0046622 is an application claiming priority based on Korean Application No. 10-2024-0057942, filed on April 30, 2024. [Background technology]

[0002] Unlike primary batteries, rechargeable batteries can be charged and discharged multiple times. Rechargeable batteries are widely used as an energy source for a variety of cordless devices such as handsets, laptops, and cordless vacuum cleaners. In recent years, improvements in energy density and economies of scale have dramatically reduced the manufacturing cost per unit capacity of rechargeable batteries, and as the driving range of battery electric vehicles (BEVs) increases to levels comparable to those of fuel-powered vehicles, the main applications of rechargeable batteries are shifting from mobile devices to mobility.

[0003] Secondary batteries are manufactured through electrode processes, assembly processes, and activation processes. Of these, the electrode process is the most crucial process for determining the yield and performance of the battery cells. The electrode process may include coating, roll pressing, and slitting processes. In the coating process, active material and insulating material may be applied to the surface of the current collector. In the roll pressing process, the electrodes may be pressed by pressure rolls. The roll pressing process can improve the density, performance, and surface quality of the electrodes. In the slitting process, the electrodes may be cut into multiple electrodes depending on the design of the battery cell. The slitting process is an optional process and may be omitted. [Overview of the project] [Problems that the invention aims to solve]

[0004] The technical concept of this invention aims to solve the problem of secondary battery manufacturing equipment with improved yield and productivity, and a method for manufacturing secondary batteries using the same. [Means for solving the problem]

[0005] According to an exemplary embodiment of the present invention for solving the above-mentioned problems, a method for manufacturing a secondary battery is provided. The method includes the steps of: applying a first electrode slurry to a current collector sheet so that a plurality of active guide lanes are formed on the current collector sheet; applying a second electrode slurry to the current collector sheet so that electrode slurry lanes are formed between the plurality of active guide lanes; and drying the plurality of active guide lanes and the electrode slurry lanes so that an active material layer is formed, wherein the solid content of the first electrode slurry is different from the solid content of the second electrode slurry.

[0006] The solid content of the first electrode slurry is smaller than the solid content of the second electrode slurry.

[0007] The solid content of the first electrode slurry is greater than the solid content of the second electrode slurry.

[0008] The wet thickness of each of the above-mentioned active guide lanes differs from the wet thickness of the above-mentioned electrode slurry lane.

[0009] The wet thickness of each of the above-mentioned active guide lanes is smaller than the wet thickness of the above-mentioned electrode slurry lane.

[0010] The wet thickness of each of the above-mentioned active guide lanes is greater than the wet thickness of the above-mentioned electrode slurry lane.

[0011] The product of the wet thickness of each of the plurality of active guide lanes and the solid content of each of the plurality of active guide lanes is the same as the product of the wet thickness of the electrode slurry lane and the solid content of the electrode slurry lane.

[0012] The method further includes applying an insulating slurry to the current collector sheet such that an insulating slurry lane is formed on the plurality of active guide lanes.

[0013] By drying the plurality of active guide lanes and the electrode slurry lane, the plurality of active guide lanes and the electrode slurry lane are integrated into the active material layer.

[0014] The dry thickness of each of the plurality of active guide lanes is the same as the dry thickness of the electrode slurry lane.

[0015] The time interval between the formation of the plurality of active guide lanes and the drying of the plurality of active guide lanes is within 2 minutes.

[0016] The solid content of each of the plurality of active guide lanes is 40% or more and 60% or less, the solid content of the electrode slurry lane is 60% or more and 80% or less.

Advantages of the Invention

[0017] According to an exemplary embodiment of the present invention, an active guide lane that limits the electrode slurry lane can be provided. Thereby, the fat edge and slide of the electrode slurry lane can be alleviated or prevented, and the yield and reliability of secondary battery manufacturing can be improved.

[0018] The effects obtained from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those having ordinary knowledge in the technical field to which the exemplary embodiments of the present disclosure belong from the following description. That is, unintended effects associated with implementing the exemplary embodiments of the present disclosure can also be derived by those having ordinary knowledge in the technical field from the exemplary embodiments of the present disclosure.

Brief Description of the Drawings

[0019] [Figure 1] Shows a secondary battery manufacturing facility according to an exemplary embodiment. [Figure 2] It is a plan view showing the processing by the secondary battery manufacturing facility according to an exemplary embodiment. [Figure 3] It is a cross-sectional view taken along the cutting line 2I-2I' of FIG. 2. [Figure 4] It is a cross-sectional view taken along the cutting line 2II-2II' of FIG. 2. [Figure 5] It is a cross-sectional view taken along the cutting line 2III-2III' of FIG. 2. [Figure 6] It is a cross-sectional view taken along the cutting line 2IV-2IV' of FIG. 2. [Figure 7] It is a flowchart for explaining a method of manufacturing a secondary battery according to an exemplary embodiment. [Figure 8] It is a plan view showing the processing by the secondary battery manufacturing facility according to an exemplary embodiment. [Figure 9] It is a cross-sectional view taken along the cutting line 8I-8I' of FIG. 8. [Figure 10] It is a cross-sectional view taken along the cutting line 8II-8II' of FIG. 8. [Figure 11] It is a cross-sectional view taken along the cutting line 8III-8III' of FIG. 8. [Figure 12] It is a cross-sectional view taken along the cutting line 8IV-8IV' of FIG. 8.

Modes for Carrying Out the Invention

[0020] Preferred embodiments of the present invention will now be described in detail with reference to the attached drawings. As a premise, terms and words used herein and in the claims are not to be interpreted in their usual or dictionary sense, but rather in a sense and concept consistent with the technical idea of ​​the present invention, based on the principle that inventors may appropriately define the concepts of terms in order to best describe their own invention.

[0021] Therefore, the embodiments described herein and the configurations shown in the drawings represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the present invention; there may be a variety of equivalents and modifications that can substitute for them at the time of filing.

[0022] Furthermore, in describing the present invention, if it is determined that a specific description of a related known configuration or function may obscure the gist of the present invention, such detailed description will be omitted.

[0023] Since embodiments of the present invention are provided to give a more complete explanation to an ordinary person, the shapes and sizes of the components in the drawings may be exaggerated, omitted, or shown schematically for the sake of clarity. Accordingly, the sizes and proportions of each component do not fully reflect the actual sizes and proportions.

[0024] (First Embodiment) Figure 1 shows a secondary battery manufacturing facility 1000 according to an exemplary embodiment.

[0025] Figure 2 is a plan view showing the processing carried out by the secondary battery manufacturing equipment 1000 according to an exemplary embodiment.

[0026] Figure 3 is a cross-sectional view along the cutting line 2I-2I' in Figure 2.

[0027] Figure 4 is a cross-sectional view along the cutting line 2II-2II' in Figure 2.

[0028] Figure 5 is a cross-sectional view along the cutting line 2III-2III' in Figure 2.

[0029] Figure 6 is a cross-sectional view along the cutting line 2IV-2IV' in Figure 2.

[0030] Referring to Figures 1 to 5, the secondary battery manufacturing equipment 1000 may include an unwinder 1011, a rewinder 1013, a first die coater 1021, a second die coater 1023, a third die coater 1025, and a drying device 1027.

[0031] The first electrode roll ER1 can be loaded into the unwinder 1011. The unwinder 1011 can be configured to unwind the current collector sheet SS from the first electrode roll ER1. The current collector sheet SS can be processed by the first die coater 1021, the second die coater 1023, the third die coater 1025 and the drying apparatus 1027 to provide the electrode sheet ES.

[0032] The rewinder 1013 may be configured to wind the electrode sheet ES onto the second electrode roll ER2. After reaching a predetermined winding target, the second electrode roll ER2 may be cut and separated from the electrode sheet ES. As a result, the current collector sheet SS and the electrode sheet ES can move between the unwinder 1011 and the rewinder 1013, and the processing by the secondary battery manufacturing equipment 1000 may be referred to as roll-to-roll processing.

[0033] The direction of movement of the current collector sheet SS and electrode sheet ES is referred to as the machine direction (MD). The machine direction MD is sometimes also referred to as the longitudinal direction of the current collector sheet SS and electrode sheet ES. The direction perpendicular to the machine direction MD is defined as the transverse direction (TD) of the current collector sheet SS and electrode sheet ES. The transverse direction TD is sometimes also referred to as the width direction of the current collector sheet SS and electrode sheet ES. The vertical direction VD may be substantially perpendicular to the machine direction MD and the transverse direction TD.

[0034] The thickness of the current collector sheet SS can range from approximately 3 μm to approximately 500 μm. The current collector sheet SS may have high conductivity without inducing chemical changes in the ultimately manufactured secondary battery. The surface of the current collector sheet SS may include a fine uneven structure to enhance the adhesion of the active material. The shape of the current collector sheet SS may include one of the following: film, sheet, foil, net, porous material, foam, and nonwoven fabric.

[0035] According to exemplary embodiments, the current collector sheet SS may be used in the manufacture of a positive electrode, and the current collector sheet SS may include, but is not limited to, stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum-cadmium alloy.

[0036] For example, the current collector sheet SS may be used in the manufacture of a negative electrode, and the current collector sheet SS may contain one of the following: copper, stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum-cadmium alloy.

[0037] The first die coater 1021 may be configured to apply a first electrode slurry to the current collector sheet SS so that a plurality of active guide lanes AGL are formed. The active guide lanes AGL may extend in the direction of travel MD. The active guide lanes AGL may be spaced apart from each other in the lateral direction TD. In this example, each of the plurality of active guide lanes AGL may be adjacent to the lateral edge TD of the current collector sheet SS.

[0038] According to exemplary embodiments, the first electrode slurry may comprise an electrode active material, a conductive material, a binder, and a solvent. An electrode slurry can be prepared by dissolving the electrode active material, conductive material, and the like in a solvent. The solvent can disperse the components of the electrode slurry, such as the electrode active material. The solvent may be an aqueous or non-aqueous solvent. The solvent may comprise any one of DMSO, isopropyl alcohol, NMP, acetone, water, and mixtures thereof.

[0039] According to an exemplary embodiment, the electrode active material can be, but is not limited to, a positive electrode active material. A positive electrode active material is a material capable of causing an electrochemical reaction. The positive electrode active material can be a lithium transition metal oxide. The positive electrode active material can include layered compounds such as lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2) substituted with one or more transition metals; lithium manganese oxide substituted with one or more transition metals; chemical formula LiNi 1+x , z , y , 1-y , e , 4-z , M y O2 (where M is any one of Co, Mn, Al, Cu, Fe, Mg, B, Cr, Zn, and Ga, and 0.01 ≦ y ≦ 0.7); Li 1+z Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O2, and Li 1+z Ni 0.4 Mn 0.4 Co 0.2 O2, such as Li 1+z Ni b Mn c Co 1-(b+c+d) M d O (2-e) A e (where -0.5 ≦ z ≦ 0.5, 0.1 ≦ b ≦ 0.8, 0.1 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.2, 0 ≦ e ≦ 0.2, b + c + d < 1, M is any one of Al, Mg, Cr, Ti, Si, and Y, and A is any one of F, P, and Cl) may include a lithium nickel cobalt manganese composite oxide represented by. The positive electrode active material can include olivine-type lithium metal phosphate represented by the chemical formula Li 1+x M 1-y M’ y PO 4-z X z (where M is a transition metal, more specifically any one of Fe, Mn, Co, and Ni, M’ is any one of Al, Mg, and Ti, X is any one of F, S, and N, -0.5 ≦ x ≦ +0.5, 0 ≦ y ≦ 0.5, and 0 ≦ z ≦ 0.1).

[0040] Also, the electrode active material may be a negative electrode active material. The negative electrode active material may contain carbon such as graphitizable carbon and graphite-based carbon. The negative electrode active material may be, for example, Li x Fe2O3 (0 ≦ x ≦ 1), Li x WO2 (0 ≦ x ≦ 1), Sn x Me 1-x Me’ y O z (where Me is any one of Mn, Fe, Pb, and Ge, Me’ is any one of Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, and halogen; 0 < x ≦ 1; 1 ≦ y ≦ 3; 1 ≦ z ≦ 8), etc. The negative electrode active material may contain a metal composite oxide. The negative electrode active material may contain, for example, any one of lithium metal; lithium alloy; silicon-based alloy; and tin-based alloy. The negative electrode active material may contain metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb@*@2O4@*@, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, and Bi2O5. The negative electrode active material may contain, for example, a conductive polymer such as polyacetylene, and a Li-Co-Ni-based material, etc.

[0041] The conductive material can have conductivity without inducing a chemical change in the finally manufactured secondary battery. The conductive material may include, for example, graphite such as natural graphite and artificial graphite; carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; metal powders such as carbon fluoride, aluminum, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide, and polyphenylene derivatives, etc. <00*@0192@*@><00*@0193@*@><00*@0194@*@>The binder can improve the adhesion between active materials and the adhesion between the current collector sheet SS and the active materials. The binder may also contain PVDF (Polyvinylidene Fluoride), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-dientelpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, and fluororubber.

[0043] The second die coater 1023 may be positioned downstream of the first die coater 1021. That is, the second die coater 1023 may be configured to process the portion of the current collector sheet SS that has been processed by the first die coater 1021. The second die coater 1023 may be interposed between the first die coater 1021 and the rewinder 1013.

[0044] The second die coater 1023 may be configured to apply the second electrode slurry to the current collector sheet SS so that an electrode slurry lane ESL is formed. The portion of the current collector sheet SS to which the active guide lane AGL and the electrode slurry lane ESL are applied may be referred to as the ground portion. The electrode slurry lane ESL may extend in the direction of travel MD.

[0045] The electrode slurry lane (ESL) may be interposed between the active guide lanes (AGL) in the lateral direction (TD). That is, the electrode slurry lane (ESL) may be applied to the portion of the current collector sheet (SS) that is limited by the active guide lanes (AGL).

[0046] The second electrode slurry may contain an electrode active material, a conductive material, a binder, and a solvent. According to exemplary embodiments, the second electrode slurry may differ from the first electrode slurry. The second electrode slurry may have a higher solids content than the first electrode slurry. The second electrode slurry may be substantially the same as the first electrode slurry except for the solids content. That is, the first electrode slurry may contain additional solvent compared to the second electrode slurry, based on the same amount of solids.

[0047] The solid content of the electrode slurry lane (ESL) may differ from the solid content of each of the multiple active guide lanes (AGL). The solid content of the electrode slurry lane (ESL) may be greater than the solid content of each of the multiple active guide lanes (AGL).

[0048] According to an exemplary embodiment, the solid content of each of the multiple active guide lanes (AGLs) may be about 40% or more. According to an exemplary embodiment, the solid content of each of the multiple active guide lanes (AGLs) may be about 45% or more. According to an exemplary embodiment, the solid content of each of the multiple active guide lanes (AGLs) may be about 60% or less. According to an exemplary embodiment, the solid content of each of the multiple active guide lanes (AGLs) may be about 55% or less.

[0049] According to exemplary embodiments, the solid content of the electrode slurry lane (ESL) may be about 60% or more. According to exemplary embodiments, the solid content of the electrode slurry lane (ESL) may be about 65% or more. According to exemplary embodiments, the solid content of the electrode slurry lane (ESL) may be about 80% or less. According to exemplary embodiments, the solid content of the electrode slurry lane (ESL) may be about 75% or less.

[0050] Due to the difference in solid content between each active guide lane AGL and the electrode slurry lane ESL, the active guide lanes AGL and ESL may not mix with each other until the drying process by the drying device 1027 is performed.

[0051] After the active guide lanes (AGL) and electrode slurry lanes (ESL) are provided, the time required for them to dry may be 5 minutes or less (or 2 minutes or less). This allows the profile of each active guide lane (AGL) to be maintained as it was when it was first coated, thereby preventing or mitigating sliding of the electrode slurry lanes (ESL) and improving the edge profile of the final active material layer (AL).

[0052] According to an exemplary embodiment, the wet thickness of the electrode slurry lane ESL may differ from the wet thickness of each of the multiple active guide lanes AGL so that the active material is uniformly distributed on the current collector sheet SS in the lateral direction TD. The wet thickness of the electrode slurry lane ESL may be less than the wet thickness of each of the multiple active guide lanes AGL. Here, the wet thickness of the electrode slurry lane ESL and each of the multiple active guide lanes AGL may be the respective thicknesses of the electrode slurry lane ESL and each of the multiple active guide lanes AGL before drying.

[0053] The second electrode slurry may have fluidity. When coating with a conventional electrode slurry, the flow of the electrode slurry forms fat edges and slides. A fat edge means an increase in the thickness (or loading amount) of the lateral edge of the electrode slurry. That is, the fat edge may have a thickness (or loading amount) greater than the target thickness (or loading amount) of the electrode slurry. A slide is a slope of the electrode slurry formed by the flow of the electrode slurry toward the lateral edge TD of the electrode sheet ES.

[0054] According to exemplary embodiments, the profile of the active material layer AL provided by drying the electrode slurry lane ESL and the active guide lane AGL can be improved by providing an active guide lane AGL before coating the electrode slurry lane ESL, thereby improving the quality of the final manufactured electrode sheet ES. Here, the improvement of the active material layer AL profile may include improving perpendicularity by removing or mitigating fat edges and slides.

[0055] The third die coater 1025 may be positioned downstream of the second die coater 1023. That is, the third die coater 1025 may be configured to process the portion of the current collector sheet SS that has been processed by the second die coater 1023. The third die coater 1025 may be interposed between the second die coater 1023 and the rewinder 1013.

[0056] The third die coater 1025 may be configured to provide insulating slurry so that insulating slurry lanes ISL are formed on the current collector sheet SS. The insulating slurry may include, for example, an insulating material, styrene butadiene rubber (SBR), a binder, a stabilizer, and a solvent. The insulating material may include a ceramic such as boehmite. The binder of the insulating slurry lane ISL may include one of the above-mentioned materials. Multiple insulating slurry lanes ISL may be separated from each other in the lateral direction TD. The insulating slurry lanes ISL may extend in the direction of travel MD.

[0057] An insulating slurry lane (ISL) may, but is not limited to, be applied on an active guide lane (AGL). In one embodiment, the insulating slurry lane (ISL) may include a portion covering the active guide lane (AGL) and a portion covering the electrode slurry lane (ESL). In one embodiment, the insulating slurry lane (ISL) may include a portion covering the active guide lane (AGL) and a portion covering the current collector sheet (SS). In one embodiment, the insulating slurry lane (ISL) may include a portion covering the active guide lane (AGL), a portion covering the current collector sheet (SS), and a portion covering the electrode slurry lane (ESL). The portion of the current collector sheet (SS) overlapping the insulating slurry lane (ISL) and the active guide lane (AGL) may be referred to as an overlay region. The overlay region may extend in the direction of travel (MD).

[0058] The drawings show an embodiment in which a first die coater 1021, a second die coater 1023, and a third die coater 1025 are sequentially arranged and operated, but the technical concept of the present invention is not limited thereto. In one embodiment, the second die coater 1023 and the third die coater 1025 may be integrally formed or arranged parallel to the lateral direction TD of the current collector sheet SS. The second die coater 1023 can be operated simultaneously with the third die coater 1025. That is, the second die coater 1023 and the third die coater 1025 may be configured to simultaneously process the portion of the current collector sheet SS processed by the first die coater 1021. This allows the electrode slurry lane ESL and the insulating slurry lane ISL to be applied simultaneously to the current collector sheet SS.

[0059] In one embodiment, the second die coater 1023 may include a plurality of discharge ports. The second die coater 1023 may be configured to discharge different types of electrode slurries through each of the multiple discharge ports. This allows the electrode slurry lane (ESL) to contain two or more types of slurries. In this case, the first die coater 1021 may also include a plurality of discharge ports. For example, the first die coater 1021 may include the same number of discharge ports as the second die coater 1023. However, it is not limited to this, and if the second die coater 1023 includes a plurality of discharge ports, the first die coater 1021 may include a single discharge port.

[0060] The drying apparatus 1027 may be positioned downstream of the third die coater 1025. That is, the drying apparatus 1027 may be configured to process the portion of the electrode sheet ES that has been processed by the third die coater 1025. The drying apparatus 1027 may be interposed between the third die coater 1025 and the rewinder 1013.

[0061] The drying apparatus 1027 may be configured to remove or reduce the solvent content in the active guide lane AGL, electrode slurry lane ESL, and insulating slurry lane ISL. Drying of the active guide lane AGL and electrode slurry lane ESL may provide an active material layer AL, and drying of the insulating slurry lane ISL may provide an insulating layer IL. The active guide lane AGL and electrode slurry lane ESL may be integrated into the active material layer AL by the drying process.

[0062] The drying apparatus 1027 may include, for example, an oven. The drying apparatus 1027 may limit the moisture content of the electrode sheet ES to a set numerical range. The drying apparatus 1027 may, but is not limited to, operate based on, for example, dew point-based feedback.

[0063] According to exemplary embodiments, as the solvent evaporates during the drying process, the decrease in the wet thickness of the active guide lane AGL may be greater than the decrease in the wet thickness of the electrode slurry lane ESL, thereby allowing the dry thickness of the active guide lane AGL to be substantially the same as the dry thickness of the electrode slurry lane ESL. The active material layer AL formed by drying the active guide lane AGL and the electrode slurry lane ESL may have a uniform thickness and / or loading amount along the transverse direction. The insulating layer IL may cover the transverse edge TD of the active material layer AL.

[0064] (Second Embodiment) Figure 7 is a flowchart illustrating a method for manufacturing a secondary battery according to an exemplary embodiment.

[0065] Referring to Figures 1, 2, 3, and 7, at P110, a first electrode slurry can be applied to the current collector sheet SS. The first electrode slurry can be provided by a first die coater 1021. By providing the first electrode slurry to the current collector sheet SS, an active guide lane AGL can be formed on the current collector sheet SS.

[0066] Referring to Figures 1, 2, 4, and 7, at P120, a second electrode slurry can be applied to the current collector sheet SS. The second electrode slurry can be provided by a second die coater 1023. By providing the second electrode slurry to the current collector sheet SS, an electrode slurry lane ESL can be formed on the current collector sheet SS.

[0067] Referring to Figures 1, 2, 5, and 7, an insulating slurry can be applied to the current collector sheet SS at P130. The insulating slurry can be provided by the third die coater 1025. By providing the insulating slurry to the current collector sheet SS, an insulating slurry lane ISL can be formed on the current collector sheet SS.

[0068] Referring to Figures 1, 2, 6, and 7, a drying process may be performed at P140. The drying process may integrate the active guide lane AGL and the electrode slurry lane ESL, providing an active material layer AL. The thicknesses of the active guide lane AGL and the electrode slurry lane ESL may be determined based on their solid content such that the active material layer AL has a constant thickness in the lateral direction TD. Here, thickness refers to the height (or length) in the vertical direction VD.

[0069] For example, if the ratio of solid content between the active guide lane (AGL) and the electrode slurry lane (ESL) is 4:7, the thickness ratio between the active guide lane (AGL) and the electrode slurry lane (ESL) may be 7:4. That is, the product of the wet thickness of the active guide lane (AGL) and the solid content of the active guide lane (AGL) may be substantially the same as the product of the wet thickness of the electrode slurry lane (ESL) and the solid content of the electrode slurry lane (ESL). As a result, the dry thickness of each of the multiple active guide lanes (AGL) may be substantially the same as the dry thickness of the electrode slurry lane (ESL).

[0070] In one embodiment, steps P110, P120, P130, and P140 are performed simultaneously, but may be performed on other parts of the electrode sheet ES. This allows the same part of the electrode sheet ES to go through steps P110 to P140 sequentially.

[0071] In another embodiment, steps P120 and P130 may be performed simultaneously. That is, after step P110 is performed, steps P120 and P130 may be performed simultaneously, followed by step P140.

[0072] Following the coating process including P110-P140, roll pressing, slitting, and notching processes may be carried out. The roll pressing process may be performed using roll pressing equipment including pressure rolls. By performing the roll pressing process, the bonding force between the electrode surface and the active material may be strengthened. This may promote the movement of lithium ions within the electrode, thereby improving the output and performance of the final secondary battery.

[0073] The slitting process is a process of separating an electrode into multiple electrodes having smaller widths in the lateral direction. The electrodes can then be cut into a shape including tabs by a notching process.

[0074] (Third embodiment) Figure 8 is a plan view showing the processing carried out by a secondary battery manufacturing facility 1000 (see Figure 1) according to an exemplary embodiment.

[0075] Figure 9 is a cross-sectional view along the cutting line 8I-8I' in Figure 8.

[0076] Figure 10 is a cross-sectional view along the cutting line 8II-8II' in Figure 8.

[0077] Figure 11 is a cross-sectional view along the cutting line 8III-8III' in Figure 8.

[0078] Figure 12 is a cross-sectional view along the cutting line 8IV-8IV' in Figure 8.

[0079] Referring to Figures 1, 8, and 12, the first die coater 1021 may provide a first electrode slurry on the current collector sheet SS. By providing the first electrode slurry, a plurality of active guide lanes AGL' may be provided.

[0080] The second die coater 1023 can provide a second electrode slurry on the current collector sheet SS. The provision of the second electrode slurry can provide an electrode slurry lane ESL'. The second electrode slurry is substantially the same as that described with reference to Figures 1 to 6.

[0081] The first electrode slurry for forming the active guide lane AGL' may differ from the second electrode slurry. The first electrode slurry may have a higher solids content than the second electrode slurry. The first electrode slurry may be substantially the same as the second electrode slurry, except for the solids content. That is, the second electrode slurry may contain additional solvent compared to the first electrode slurry, based on the same amount of solids.

[0082] The solid content of each of the multiple active guide lanes AGL' may differ from the solid content of the electrode slurry lane ESL'. The solid content of each of the multiple active guide lanes AGL' may be greater than the solid content of the electrode slurry lane ESL'.

[0083] According to an exemplary embodiment, the solid content of each of the multiple active guide lanes AGL' may be about 70% or more. According to an exemplary embodiment, the solid content of each of the multiple active guide lanes AGL' may be about 75% or more. According to an exemplary embodiment, the solid content of each of the multiple active guide lanes AGL' may be about 90% or less. According to an exemplary embodiment, the solid content of each of the multiple active guide lanes AGL' may be about 85% or less.

[0084] Due to the difference in solid content between each active guide lane AGL' and the electrode slurry lane ESL', the active guide lanes AGL' and ESL' may not mix with each other until the drying process by the drying device 1027 is performed.

[0085] After the active guide lanes AGL' and electrode slurry lanes ESL' are provided, the time required for them to dry may be 5 minutes or less (or 2 minutes or less). This allows the profile of each active guide lane AGL' to be maintained as identical or similar to when each active guide lane AGL' was first coated, thus preventing or mitigating sliding of the electrode slurry lanes ESL'. The edge profile of the final provided active material layer AL may be improved.

[0086] According to an exemplary embodiment, the wet thickness of the electrode slurry lane ESL' may differ from the wet thickness of the active guide lane AGL' so that the active material is uniformly distributed on the current collector sheet SS in the lateral direction TD. The wet thickness of the electrode slurry lane ESL' may be greater than the wet thickness of the active guide lane AGL'.

[0087] According to an exemplary embodiment, the profile of the electrode slurry lane ESL' can be improved by providing an active guide lane AGL' before coating the electrode slurry lane ESL', thereby improving the quality of the final manufactured electrode sheet ES.

[0088] Multiple insulating slurry lanes (ISLs) applied by the third die coater 1025 can be applied on the active guide lane (AGL'). Each insulating slurry lane (ISL) is substantially the same as those described with reference to Figures 1 to 6.

[0089] The drying apparatus 1027 can remove or reduce the solvent content in the active guide lane AGL', electrode slurry lane ESL', and insulating slurry lane ISL, thereby providing the active material layer AL and the insulating layer IL.

[0090] The present invention has been described in more detail above with reference to the drawings and embodiments. However, the configurations described in the drawings or embodiments described herein are merely one embodiment of the present invention and do not represent the entire technical concept of the present invention. Therefore, there may be various equivalents and modifications that can be substituted for them at the time of filing.

Claims

1. The steps include: applying a first electrode slurry to the current collector sheet so that multiple active guide lanes are formed on the current collector sheet; The steps include applying a second electrode slurry to the current collector sheet so that an electrode slurry lane is formed between the plurality of active guide lanes, The process includes the step of drying the plurality of active guide lanes and the electrode slurry lanes so that an active material layer is formed, A method for manufacturing a secondary battery, wherein the solid content of the first electrode slurry is different from the solid content of the second electrode slurry.

2. A method for manufacturing a secondary battery according to claim 1, wherein the solid content of the first electrode slurry is smaller than the solid content of the second electrode slurry.

3. A method for manufacturing a secondary battery according to claim 1, wherein the solid content of the first electrode slurry is greater than the solid content of the second electrode slurry.

4. A method for manufacturing a secondary battery according to claim 1, wherein the wet thickness of each of the plurality of active guide lanes is different from the wet thickness of the electrode slurry lane.

5. A method for manufacturing a secondary battery according to claim 1, wherein the wet thickness of each of the plurality of active guide lanes is smaller than the wet thickness of the electrode slurry lane.

6. A method for manufacturing a secondary battery according to claim 1, wherein the wet thickness of each of the plurality of active guide lanes is greater than the wet thickness of the electrode slurry lane.

7. A method for manufacturing a secondary battery according to claim 1, wherein the product of the wet thickness of each of the plurality of active guide lanes and the solid content of each of the active guide lanes is the same as the product of the wet thickness of the electrode slurry lane and the solid content of the electrode slurry lane.

8. A method for manufacturing a secondary battery according to claim 1, further comprising the step of applying an insulating slurry to the current collector sheet such that insulating slurry lanes are formed on the plurality of active guide lanes.

9. A method for manufacturing a secondary battery according to claim 1, wherein the active guide lanes and the electrode slurry lanes are integrated into the active material layer by drying the plurality of active guide lanes and the electrode slurry lanes.

10. A method for manufacturing a secondary battery according to claim 1, wherein the drying thickness of each of the plurality of active guide lanes is the same as the drying thickness of the electrode slurry lane.

11. A method for manufacturing a secondary battery according to claim 1, wherein the time interval between the formation of the plurality of active guide lanes and the drying of the active guide lanes is 2 minutes or less.

12. The solid content of each of the aforementioned multiple active guide lanes is 40% or more. The solid content of each of the aforementioned multiple active guide lanes is 60% or less. The solid content of the electrode slurry lane is 60% or more. A method for manufacturing a secondary battery according to claim 1, wherein the solid content of the electrode slurry lane is 80% or less.

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