Method of manufacturing secondary battery and electrode

Abstract

According to an example embodiment, a method for manufacturing a secondary battery is provided. The method includes the following steps: forming a first coating comprising a first active material layer and a second active material layer on a first surface of a current collector sheet; magnetizing the first active material layer; drying the first coating; forming a second coating comprising a third active material layer and a fourth active material layer on a second surface of the current collector sheet opposite to the first surface; magnetizing the third active material layer; drying the second coating; performing a rolling process on an electrode sheet comprising the current collector sheet, the first coating, and the second coating; and patterning the electrode sheet such that a plurality of grooves are formed in the second and fourth active material layers.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a secondary battery manufacturing method and an electrode. This application claims the priority benefit of Korean Patent Application No. 10-2024-0112361 filed on August 21, 2024, Korean Patent Application No. 10-2025-0058427 filed on May 2, 2025, and Korean Patent Application No. 10-2025-0116290 filed on August 21, 2025, and the entire contents of these Korean patent applications are incorporated herein by reference. BACKGROUND

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. Secondary batteries are widely used as energy sources for various wireless devices such as mobile phones, notebook computers, and cordless vacuum cleaners. Recently, as the manufacturing cost per unit capacity of secondary batteries has been significantly reduced due to the improvement in energy density and economies of scale, and the range of battery electric vehicles (BEVs) has increased to the same level as that of fuel vehicles, the main use of secondary batteries has shifted from mobile devices to vehicles.

[0003] Secondary batteries are manufactured through an electrode process, an assembly process, and an activation process. Among these processes, the electrode process is a key process that determines the yield and performance of the battery cell. The electrode process can include a coating process, a roll-pressing process, and a cutting process. In the coating process, an active material and an insulating material can be coated onto the surface of a current collector. In the roll-pressing process, the electrode can be pressed by a pressing roller. In the roll-pressing process, the density, performance, and surface quality of the electrode can be improved. In the cutting process, the electrode can be cut into a plurality of electrodes according to the design of the battery cell. The cutting process is an optional process, and thus can be omitted. SUMMARY

[0004] TECHNICAL PROBLEM

[0005] The present disclosure relates to a secondary battery manufacturing method and an electrode for manufacturing a battery cell with improved charging speed.

[0006] TECHNICAL SOLUTION

[0007] An embodiment of the present disclosure provides a secondary battery manufacturing method. The method includes forming a first coating layer including a first active material layer and a second active material layer on a first surface of a current collector sheet; magnetizing the first active material layer; drying the first coating layer; forming a second coating layer including a third active material layer and a fourth active material layer on a second surface of the current collector sheet opposite the first surface; magnetizing the third active material layer; drying the second coating layer; performing a roll-pressing process on an electrode sheet including the current collector sheet, the first coating layer, and the second coating layer; and patterning the electrode sheet to form a plurality of grooves in the second active material layer and the fourth active material layer.

[0008] The electrode sheet can be patterned by a patterning roller.

[0009] The depth of each of the plurality of grooves can be different from the depth of the second active material layer.

[0010] The depth of each of the plurality of grooves can be less than the depth of the second active material layer.

[0011] Each of the plurality of grooves can extend in a machine direction of the electrode sheet.

[0012] The first active material layer can include a material different from that of the second active material layer, and the third active material layer can include a material different from that of the fourth active material layer.

[0013] Each of the first and third active material layers can include natural graphite, and each of the second and fourth active material layers can include artificial graphite.

[0014] Embodiments provide an electrode. The electrode includes an electrode plate, a first active material layer on a first surface of the electrode plate, and a second active material layer on the first active material layer.

[0015] The first active material layer can include a material different from that of the second active material layer.

[0016] The remanence of the first active material layer can be different from that of the second active material layer.

[0017] The remanence of the first active material layer can be greater than that of the second active material layer.

[0018] The surface alignment degree of the first active material layer can be different from that of the second active material layer.

[0019] The surface alignment degree of the first active material layer can be higher than that of the second active material layer.

[0020] The first active material layer can include natural graphite, and the second active material layer can include artificial graphite.

[0021] The first active material layer can be magnetized.

[0022] The depth of each of the plurality of grooves can be less than the depth of the second active material layer.

[0023] Each of the plurality of grooves can extend in a first direction parallel to the electrode plate.

[0024] The plurality of grooves can be spaced apart from each other in a second direction perpendicular to the first direction.

[0025] The depth of each of the multiple grooves may be different from the sum of the depths of the first active material layer and the second active material layer.

[0026] The depth of each of the multiple grooves can be less than the sum of the depths of the first active material layer and the second active material layer.

[0027] Each of the first and second active material layers may include artificial graphite and natural graphite.

[0028] The mass percentage of natural graphite in the first active material layer can differ from the mass percentage of natural graphite in the second active material layer.

[0029] The mass percentage of natural graphite in the first active material layer can be greater than the mass percentage of natural graphite in the second active material layer.

[0030] The mass percentage of artificial graphite in the first active material layer can differ from the mass percentage of artificial graphite in the second active material layer.

[0031] The mass percentage of artificial graphite in the first active material layer can be less than the mass percentage of artificial graphite in the second active material layer.

[0032] Beneficial effects

[0033] According to embodiments of this disclosure, an electrode comprising a coating including a first active material layer comprising natural graphite and a second active material layer comprising artificial graphite can be provided. The first active material layer of the electrode can be on a current collector sheet. The first active material layer can be magnetized, and thus the magnetic molecules of the first active material layer can be magnetically aligned. The second active material layer can be on the first active material layer, and a patterning process can be performed on the second active material layer. The charging speed of a battery cell manufactured based on the electrode sheet can be improved by magnetizing the first active material layer and patterning the second active material layer.

[0034] The effects achievable by the embodiments of this disclosure are not limited to those described above, and those skilled in the art to which the embodiments of this disclosure pertain will clearly derive and understand from the following description other effects not described herein. In other words, those skilled in the art can deduce from the embodiments of this disclosure unintended effects when implementing the embodiments of this disclosure. Attached Figure Description

[0035] Figure 1 This is a flowchart of a secondary battery manufacturing method according to an embodiment.

[0036] Figure 2 A secondary battery manufacturing apparatus according to an embodiment is shown.

[0037] Figure 3 This is a cross-sectional view of an electrode sheet processed by a secondary battery manufacturing apparatus according to an embodiment.

[0038] Figure 4 A secondary battery manufacturing apparatus according to an embodiment is shown.

[0039] Figure 5 This is a cross-sectional view of a patterned electrode sheet processed by a secondary battery manufacturing apparatus according to an embodiment.

[0040] Figure 6 This is a perspective view used to describe the second and fourth active material layers according to the embodiments.

[0041] Figure 7 This is a perspective view used to describe the second and fourth active material layers according to the embodiments.

[0042] Figure 8 This is a perspective view used to describe the electrodes according to the embodiment.

[0043] Figure 9 This is a perspective view used to describe the electrode assembly according to an embodiment.

[0044] Figure 10 This is an exploded perspective view of a battery cell according to an embodiment.

[0045] Figure 11 This is a cross-sectional view of a patterned electrode sheet according to other embodiments.

[0046] Figure 12 This is a perspective view used to describe the electrodes according to the embodiment.

[0047] Figure 13 This is a diagram used to describe a secondary battery manufacturing apparatus according to an embodiment. Detailed Implementation

[0048] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before describing embodiments of the present disclosure, the terms or expressions used in this specification and claims should not be construed as limited to the conventional understanding or definition in commonly used dictionaries, but should be understood based on the principle that the inventors of this application can appropriately define the terms or expressions to best interpret the present disclosure, according to the meanings and concepts corresponding to the present disclosure.

[0049] Therefore, the embodiments described herein and the configurations shown in the accompanying drawings are merely examples of this disclosure and do not reflect all the technical concepts of this disclosure. It should be understood that various equivalents and modifications to these configurations may exist as of the filing date of this application.

[0050] When a well-known configuration or function related to the description of this disclosure is determined to obscure the subject matter of this disclosure due to unnecessary detail, it will not be described in detail.

[0051] Because the embodiments of this disclosure are provided to explain the disclosure more fully to those skilled in the art, the shapes, dimensions, etc. of the components shown in the drawings may be enlarged, omitted, or illustrated schematically for clarity. Therefore, it should not be construed that the dimensions or proportions of the components completely reflect their actual dimensions or proportions.

[0052] (First and Second Embodiments)

[0053] Figure 1 This is a flowchart of a secondary battery manufacturing method according to an embodiment.

[0054] Figure 2 A secondary battery manufacturing apparatus 1100 according to an embodiment is shown.

[0055] Figure 3 This is a cross-sectional view of the electrode sheet ES processed by the secondary battery manufacturing equipment 1100 according to an embodiment.

[0056] Figure 4 A secondary battery manufacturing apparatus 1200 according to an embodiment is shown.

[0057] Figure 5 This is a cross-sectional view of a patterned electrode sheet (PES) processed by a secondary battery manufacturing apparatus 1200 according to an embodiment.

[0058] Reference Figures 1 to 3 In P110, a first coating C1 can be formed on the first surface CS1 of the current collector CS. The first coating C1 can be formed by the secondary battery manufacturing equipment 1100.

[0059] The secondary battery manufacturing equipment 1100 may include an unwinder 1111, a rewinder 1113, a first mold coater 1121, a second mold coater 1123, a third mold coater 1125, a fourth mold coater 1127, a first magnetizing device 1131, a second magnetizing device 1133, a first drying device 1141, a second drying device 1143, and a guide roller 1150.

[0060] The current collector roll CR can be mounted on the unwinder 1111. The unwinder 1111 can be configured to unwind the current collector sheet CS from the current collector roll CR. The electrode sheet ES can be provided by processing the current collector sheet CS by a first mold coater 1121, a second mold coater 1123, a third mold coater 1125, a fourth mold coater 1127, a first magnetization device 1131, a second magnetization device 1133, a first drying device 1141, and a second drying device 1143.

[0061] The rewinder 1113 can be configured to wind the electrode sheet ES into an electrode roll ER. After the target winding amount is reached, the electrode roll ER can be cut and separated from the electrode sheet ES. Therefore, the current collector CS and the electrode sheet ES can move between the unwinder 1111 and the rewinder 1113, and the processing of the secondary battery manufacturing equipment 1100 can be roll-to-roll processing.

[0062] The direction of movement of the current collector CS and the electrode ES will be referred to as the machine direction MD in the following text. The machine direction MD can also refer to the longitudinal direction of the current collector CS and the electrode ES. The direction perpendicular to the machine direction MD will be defined as the transverse direction TD of the current collector CS and the electrode ES in the following text. The transverse direction TD can also be referred to as the width direction of the current collector CS and the electrode ES. The vertical direction VD can be substantially perpendicular to the machine direction MD and the transverse direction TD.

[0063] The thickness of the current collector CS can range from approximately 3 μm to approximately 500 μm. The current collector CS may not cause chemical changes in the final manufactured secondary battery and may exhibit high conductivity. The surface of the current collector CS can have a finely non-uniform structure to increase the adhesion of the active material. The current collector CS can be in the form of a film, sheet, foil, mesh, pores, foam, or nonwoven fabric.

[0064] For example, current collectors (CS) can be used to manufacture negative electrodes and can include, but are not limited to, copper, stainless steel, aluminum, nickel, titanium, baked carbon, or aluminum-cadmium alloys. Current collectors (CS) can also be used to manufacture positive electrodes.

[0065] The first mold coater 1121 can be configured to coat a first electrode slurry onto a current collector CS to form a first active material layer AL1. The first active material layer AL1 can be on a first surface CS1 of the current collector CS. The first active material layer AL1 can extend in the machine direction MD. In the following, although the first active material layer AL1 is shown, multiple first active material layers can be simultaneously formed to be spaced apart from each other in the transverse direction TD to form multiple coating strips.

[0066] According to an embodiment, the first electrode slurry may include a first electrode active material, a conductive additive, a binder, and a solvent. The electrode slurry can be prepared by dissolving the electrode active material, the conductive additive, and the binder in a solvent. The solvent disperses the components of the electrode slurry, such as the electrode active material. The solvent may be an aqueous solvent or a non-aqueous solvent. The solvent may contain DMSO, isopropanol, NMP, acetone, water, or mixtures thereof.

[0067] According to an embodiment, the first electrode active material can be a negative electrode active material. According to an embodiment, the first electrode active material can include natural graphite. According to an embodiment, the first electrode active material can also include a silicon-based negative electrode active material. The silicon-based negative electrode active material can be, but is not limited to, amorphous silicon, crystalline silicon, silicon oxide, silicon-carbon composite materials (such as SiC, Si@C, Si-C, Si-CNT, and Si-graphene) or silicon alloys (such as Si-Sn, Si-Al, and Si-Ti).

[0068] Conductive additives can be conductive and do not cause chemical changes in the final manufactured secondary battery. Conductive additives may include: carbon black, such as acetylene black, Ketjen black, channel black, furnace black, lampblack, or thermal cracking black; conductive fibers, such as carbon fibers or metal fibers; metal powders, such as fluorinated carbon, aluminum, or nickel powder; conductive styrene, such as zinc oxide or potassium titanate; conductive metal oxides, such as titanium oxide; polyphenylene derivatives, etc.

[0069] Binders can improve the adhesion strength between active materials and between the current collector sheet (CS) and the active materials. Binders may include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, etc.

[0070] The second mold coater 1123 may be disposed downstream of the first mold coater 1121. The second mold coater 1123 may be configured to process a portion of the current collector sheet CS processed by the first mold coater 1121. The second mold coater 1123 may be inserted between the first mold coater 1121 and the rewinder 1113.

[0071] The second mold coater 1123 can be configured to coat a second electrode paste onto the current collector CS to form a second active material layer AL2. The second active material layer AL2 can be a first active material layer AL1. The second active material layer AL2 can extend in the machine direction MD. A first coating C1 comprising the first active material layer AL1 and the second active material layer AL2 can be formed by forming the second active material layer AL2. The first coating C1 can extend in the machine direction MD.

[0072] The second electrode paste may include a second electrode active material, conductive additives, a binder, and a solvent. According to an embodiment, the second electrode paste may differ from the first electrode paste. The second electrode active material of the second electrode paste may differ from the first electrode active material of the first electrode paste. According to an embodiment, the second electrode active material may include artificial graphite. According to an embodiment, the second electrode active material may also include a silicon-based anode active material.

[0073] The weight percentage of the binder in the second electrode slurry can be less than the weight percentage of the binder in the first electrode slurry. The binder has a relatively low molecular weight and therefore floats during the drying of the first coating C1. According to an embodiment, since the weight percentage of the binder in the second electrode slurry is less than the weight percentage of the binder in the first electrode slurry, the uniformity of the binder distribution in the first coating C1 can be improved after drying.

[0074] The conductive additives and solvents in the second electrode paste can be substantially the same as those in the first electrode paste. Except for their weight percentages, the binders in the second electrode paste can be the same as those in the first electrode paste.

[0075] Next, in P120, the first active material layer AL1 of the first coating C1 can be magnetized. The first active material layer AL1 can be magnetized by the first magnetization device 1131. The first magnetization device 1131 may include a permanent magnet or an electromagnet, but the implementation is not limited thereto.

[0076] The first magnetizing device 1131 may be disposed downstream of the second mold coater 1123. The first magnetizing device 1131 may be configured to process a portion of the current collector sheet CS processed by the second mold coater 1123. The first magnetizing device 1131 may be inserted between the second mold coater 1123 and the rewinder 1113.

[0077] The first active material layer AL1 may include a magnetic material. The second active material layer AL2 may include a material different from that of the first active material layer AL1. The second active material layer AL2 may include a diamagnetic material. The magnetic moments of the magnetic molecules in the first active material layer AL1 can be aligned by magnetizing the first active material layer AL1. Typically, natural graphite contains magnetic molecules in the form of impurities and can therefore be magnetized, but the degree of magnetization of artificial graphite may be lower. Therefore, in P120, the first active material layer AL1 can be magnetized, and the degree of magnetization of the second active material layer AL2 may be lower than that of the first active material layer AL1.

[0078] The remanence of the first active material layer AL1 can be different from that of the second active material layer AL2. The remanence of the first active material layer AL1 can be greater than that of the second active material layer AL2.

[0079] The surface alignment of the first active material layer AL1 can differ from that of the second active material layer AL2. The surface alignment of the first active material layer AL1 can be higher than that of the second active material layer AL2.

[0080] Next, in P130, the first coating C1 can be dried. The first coating C1 can be dried by the first drying device 1141. The first drying device 1141 can be located downstream of the first magnetizing device 1131. The first drying device 1141 can be configured to process a portion of the electrode sheet ES processed by the first magnetizing device 1131. The first drying device 1141 can be inserted between the first magnetizing device 1131 and the rewinder 1113.

[0081] The first drying device 1141 can be configured to remove solvent from the first coating C1 or reduce the solvent content. The first drying device 1141 may include, for example, an oven. The first drying device 1141 can limit the moisture content of the electrode sheet ES within a set numerical range. The first drying device 1141 can operate based on, for example, dew point-based feedback, but the implementation is not limited thereto.

[0082] Next, in P140, a second coating C2 can be formed on the second surface C2 of the current collector CS. In order to process the second surface CS2, the current collector CS can be guided by the guide roller 1150 so that the second surface CS2 of the current collector CS faces the top plate of the place where the secondary battery manufacturing equipment 1100 is installed (or the first surface CS1 faces the bottom surface of that place).

[0083] The second coating C2 may include a third active material layer AL3 and a fourth active material layer AL4. Forming the second coating C2 on the second surface CS2 of the current collector CS may include forming the third active material layer AL3 on the second surface CS2 of the current collector CS by a third mold coater 1125, and forming the fourth active material layer AL4 on the third active material layer AL3 by a fourth mold coater 1127.

[0084] The third mold coater 1125 may be disposed downstream of the first drying device 1141. The third mold coater 1125 may be configured to process a portion of the current collector sheet CS processed by the first drying device 1141. The third mold coater 1125 may be inserted between the first drying device 1141 and the rewinder 1113.

[0085] A fourth mold coater 1127 may be disposed downstream of the third mold coater 1125. The fourth mold coater 1127 may be configured to process a portion of the current collector sheet CS processed by the third mold coater 1125. The fourth mold coater 1127 may be inserted between the third mold coater 1125 and the rewinder 1113.

[0086] The third active material layer AL3 can be substantially the same as the first active material layer AL1. The third mold coater 1125 can be configured to provide a third electrode paste to the current collector sheet CS. The third electrode paste is substantially the same as the first electrode paste, so its repeated description is omitted here.

[0087] The fourth active material layer AL4 can be substantially the same as the second active material layer AL2. The fourth mold coater 1127 can be configured to provide a fourth electrode paste to the current collector sheet CS. The fourth electrode paste is substantially the same as the second electrode paste, so its repeated description is omitted here.

[0088] Next, in P150, the third active material layer AL3 can be magnetized. The third active material layer AL3 can be magnetized by the second magnetization device 1133. The second magnetization device 1133 may include a permanent magnet or an electromagnet, but the implementation is not limited thereto.

[0089] The second magnetizing device 1133 can be disposed downstream of the fourth mold coater 1127. The second magnetizing device 1133 can be configured to process a portion of the current collector sheet CS processed by the fourth mold coater 1133. The second magnetizing device 1133 can be inserted between the fourth mold coater 1127 and the rewinder 1113.

[0090] The third active material layer AL3 may include a magnetic material. The fourth active material layer AL4 may include a material different from that of the third active material layer AL3. The fourth active material layer AL4 may include a diamagnetic material. The magnetic moments of the magnetic molecules in the third active material layer AL3 can be aligned by magnetization of the third active material layer AL3. Therefore, in P150, the third active material layer AL3 can be magnetized, and the degree of magnetization of the fourth active material layer AL4 can be lower than that of the third active material layer AL3. The remanence of the third active material layer AL3 may differ from that of the fourth active material layer AL4. The remanence of the third active material layer AL3 may be greater than that of the fourth active material layer AL4.

[0091] The surface alignment of the third active material layer AL3 can differ from that of the fourth active material layer AL4. The surface alignment of the third active material layer AL3 can be higher than that of the fourth active material layer AL4.

[0092] According to an embodiment, each of the first electrode active material and the second electrode active material may include natural graphite and artificial graphite. According to an embodiment, the mixing ratio of natural graphite and artificial graphite in the first electrode active material may differ from the mixing ratio of natural graphite and artificial graphite in the second electrode active material.

[0093] According to an embodiment, the mass percentage of natural graphite in the first electrode active material may differ from the mass percentage of natural graphite in the second electrode active material. According to an embodiment, the mass percentage of natural graphite in the first electrode active material may be higher than the mass percentage of natural graphite in the second electrode active material.

[0094] According to an embodiment, the mass percentage of artificial graphite in the first electrode active material may differ from the mass percentage of artificial graphite in the second electrode active material. According to an embodiment, the mass percentage of artificial graphite in the first electrode active material may be lower than the mass percentage of artificial graphite in the second electrode active material.

[0095] According to other embodiments, the mass percentage of natural graphite in the first electrode active material may be lower than the mass percentage of natural graphite in the second electrode active material. According to other embodiments, the mass percentage of artificial graphite in the first electrode active material may be higher than the mass percentage of artificial graphite in the second electrode active material.

[0096] When each of the first and second electrode active materials comprises natural graphite and artificial graphite, the first to fourth active material layers AL1, AL2, AL3, and AL4 can be magnetized. That is, in P120, the first active material layer AL1 and the second active material layer AL2 can be magnetized, and in P150, the third active material layer AL3 and the fourth active material layer AL4 can be magnetized.

[0097] Next, in P160, the second coating C2 can be dried. The second coating C2 can be dried by the second drying device 1143. The second drying device 1143 can be located downstream of the second magnetizing device 1133. The second drying device 1143 can be configured to process a portion of the electrode sheet ES processed by the second magnetizing device 1133. The second drying device 1143 can be inserted between the second magnetizing device 1133 and the rewinder 1113.

[0098] The second drying device 1143 can be configured to remove solvent from the second coating C1 or reduce the solvent content. The second drying device 1143 can operate in substantially the same manner as the first drying device 1141.

[0099] Subsequently, refer to Figure 1 , Figure 4 and Figure 5 In P170, a rolling process can be performed on the electrode sheet ES. The rolling process can be performed by the secondary battery manufacturing equipment 1200.

[0100] The secondary battery manufacturing apparatus 1200 may include a dewinder 1211, a rewinder 1213, work rollers 1221 and 1223, and patterning rollers 1231 and 1233. Electrode rolls ER may be mounted on the dewinder 1211. The dewinder 1211 may be configured to unwind electrode sheets ES from the electrode rolls ER. Patterned electrode sheets PES can be provided when the electrode sheets ES are processed by the work rollers 1221 and 1223 and the patterning rollers 1231 and 1233.

[0101] The rewinder 1113 can be configured to wind the patterned electrode sheet PES into a patterned electrode roll PER. After reaching the target winding amount, the patterned electrode roll PER can be cut and separated from the patterned electrode sheet ES. Therefore, the electrode sheet ES and the patterned electrode sheet PES can move between the unwinder 1211 and the rewinder 1213, and the processing of the secondary battery manufacturing equipment 1200 can be roll-to-roll processing.

[0102] The rolling process can be performed by work rolls 1221 and 1223. The electrode sheet ES can pass between work rolls 1221 and 1223. The rolling process can flatten the surface of the electrode sheet ES and improve the adhesion between the current collector sheet CS and the first coating C1 and the second coating C2.

[0103] Next, refer to Figure 1 and Figures 3 to 5 In P180, the electrode sheet ES can be patterned. The electrode sheet ES can be patterned by patterning rollers 1231 and 1233. Patterning rollers 1231 and 1233 can be disposed downstream of work rollers 1221 and 1223. Therefore, patterning rollers 1231 and 1233 can be configured to process the electrode sheet ES processed by work rollers 1221 and 1223.

[0104] The patterning roller 1231 may have a surface including irregular portions. A portion of the second active material layer AL2 can be removed by the patterning roller 1231. The second active material layer AL2 can be roughened by the patterning roller 1231. A second active material layer AL2' with a patterned surface can be formed by the patterning roller 1231. Furthermore, a first coating C1' including the first active material layer AL1 and the second active material layer AL2' can be provided by the patterning roller 1231.

[0105] The second active material layer AL2' may include a plurality of grooves GV1. The depth of each of the plurality of grooves GV1 may be different from the thickness of the second active material layer AL2'. The depth of each of the plurality of grooves GV1 may be less than the thickness of the second active material layer AL2'. According to an embodiment, the surface of the second active material layer AL2' may be patterned to increase the specific surface area of ​​the second active material layer AL2'.

[0106] The patterning roller 1233 may have a surface including irregular portions. A portion of the fourth active material layer AL4 can be removed by the patterning roller 1233. The fourth active material layer AL4 can be roughened by the patterning roller 1233. A fourth active material layer AL4' with a patterned surface can be formed by the patterning roller 1233. Furthermore, a second coating C2' including the third active material layer AL3 and the fourth active material layer AL4' can be provided by the patterning roller 1233.

[0107] The fourth active material layer AL4' may include a plurality of grooves GV2. The depth of each of the plurality of grooves GV2 may be different from the thickness of the fourth active material layer AL4'. The depth of each of the plurality of grooves GV2 may be less than the thickness of the fourth active material layer AL4'. According to an embodiment, the surface of the fourth active material layer AL4' may be patterned to increase the specific surface area of ​​the fourth active material layer AL4'.

[0108] According to the embodiment, the first active material layer AL1 and the third active material layer AL3 are magnetized, and the second active material layer AL2' and the fourth active material layer AL4' are patterned, and therefore, the charging speed of the battery cell manufactured using patterned electrode sheets PES can be improved.

[0109] (Second Implementation)

[0110] Figure 6 This is a perspective view used to describe the second active material layer AL2' and the fourth active material layer AL4' according to the embodiments.

[0111] Reference Figure 5 and Figure 6 Multiple grooves GV1 can extend along the X-axis. Multiple grooves GV1 can be spaced apart from each other along the Y-axis. The Y-axis can be substantially perpendicular to the X-axis. Multiple grooves GV2 can extend along the X-axis. Multiple grooves GV2 can be spaced apart from each other along the Y-axis.

[0112] Each of the X-axis and Y-axis directions can be substantially parallel to the first surface CS1 and the second surface CS2 of the current collector CS. The Z-axis direction can be substantially perpendicular to the X-axis and Y-axis directions. For example, the X-axis direction can be parallel to the machine direction MD, and the Y-axis direction can be parallel to the transverse direction TD.

[0113] According to some embodiments, each of the plurality of grooves GV1 can extend in the machine direction MD. The plurality of grooves GV1 can be spaced apart from each other in the lateral direction TD. Each of the plurality of grooves GV2 can extend in the machine direction MD. The plurality of grooves GV2 can be spaced apart from each other in the lateral direction TD.

[0114] According to some embodiments, each of the plurality of grooves GV1 may extend in the lateral direction TD. The plurality of grooves GV1 may be spaced apart from each other in the machine direction MD. Each of the plurality of grooves GV2 may extend in the lateral direction TD. The plurality of grooves GV2 may be spaced apart from each other in the machine direction MD.

[0115] (Third Implementation)

[0116] Figure 7 This is a perspective view used to describe the second active material layer AL2' and the fourth active material layer AL4' according to the embodiments.

[0117] Reference Figure 7When viewed in a plan view, multiple grooves GV1' can be in the form of points. Multiple grooves GV1' can be arranged in a matrix. When viewed in a plan view, multiple grooves GV2' can be in the form of points. Multiple grooves GV2' can be arranged in a matrix pattern. Multiple grooves GV2' can be arranged in a honeycomb pattern.

[0118] (Fourth Implementation)

[0119] Figure 8 This is a cross-sectional view used to describe the electrode PE according to the embodiment.

[0120] Reference Figure 8 The electrode PE may include an electrode plate CS', a first coating C1', and a second coating C2'. The first coating C1' may include a first active material layer AL1 and a second active material layer AL2'. The second coating C2' may include a third active material layer AL3 and a fourth active material layer AL4'.

[0121] Electrode PE can be cut in the transverse direction TD Figure 5 Patterned electrode sheets (PES) are provided. The electrode plate CS' can be cut along the lateral direction TD. Figure 5 The current collector CS is formed. The first active material layer AL1, the second active material layer AL2', the third active material layer AL3, and the fourth active material layer AL4' are as described above. Figures 1 to 5 The descriptions are essentially the same, so repeated descriptions are omitted here.

[0122] (Fifth implementation method)

[0123] Figure 9 This is a perspective view used to describe the electrode assembly EA according to an embodiment.

[0124] Reference Figure 9 The electrode assembly EA may include the electrode PE, the electrode EL, and the diaphragm SRS.

[0125] Electrode PE and the above reference Figure 8 The descriptions are essentially the same. Electrode EL can have a polarity opposite to that of electrode PE. Electrode EL can include electrode plate EP, a third coating C3, and a fourth coating C4.

[0126] The thickness of the electrode plate EP can range from about 3 μm to about 500 μm. The electrode plate EP may not cause chemical changes in the final manufactured secondary battery and can have high conductivity. The electrode plate EP can include, for example, stainless steel, nickel, titanium, calcined carbon, or aluminum. The electrode plate EP can include stainless steel surface-treated with carbon, nickel, titanium, silver, etc. The surface of the electrode plate EP can include a finely textured, uneven structure to increase the adhesion of the active material. The electrode plate EP can be in the form of a film, sheet, foil, mesh, pores, foam, or nonwoven fabric.

[0127] The third coating C3 may be applied to the first surface of the electrode plate EP. The fourth coating C4 may be applied to the second surface of the electrode plate EP. The first surface and the second surface of the electrode plate EP are opposite to each other. The third coating C3 and the fourth coating C4 may include, for example, a positive electrode active material.

[0128] Positive electrode active materials are materials that can induce electrochemical reactions. Positive electrode active materials can be lithium transition metal oxides. For example, positive electrode active materials can include: layered compounds substituted with one or more transition metals, such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2); lithium manganese oxides substituted with one or more transition metals; and materials with the chemical formula LiNi... 1-y M y O2 represents lithium nickel oxides (where M is Co, Mn, Al, Cu, Fe, Mg, B, Cr, Zn, or Ga, and 0.01 ≤ y ≤ 0.7); Li 1+z Ni b Mn c Co 1-（b+c+d） M d O （2-e） A represents lithium-nickel-cobalt-manganese composite oxides, such as Li 1+z Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O2 or Li 1+z Ni 0.4 Mn 0.4 Co 0.2 O2 (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 Al, Mg, Cr, Ti, Si or Y, and A is F, P or Cl); or by chemical formula Li 1+x M 1-y M' y PO 4-z X zThe olivine-type lithium metal phosphate is represented as follows (where M is a transition metal, and more specifically Fe, Mn, Co or Ni, M' is Al, Mg or Ti, X is F, S or N, -0.5≤x≤+0.5, 0≤y≤0.5, and 0≤z≤0.1).

[0129] The portion of the electrode plate EP coated with the third coating C3 and the fourth coating C4 (i.e., overlapping with the third coating C3 and the fourth coating C4) can be referred to as the coated portion, and the portion of the electrode plate EP not coated with the third coating C3 and the fourth coating C4 (i.e., spaced apart from the third coating C3 and the fourth coating C4) can be referred to as the uncoated portion. The uncoated portion of the electrode plate EP can be the electrode tab ET of the electrode plate EP. The electrode tab ET can be an external connection terminal of the electrode EL. The width of the electrode tab ET can be less than the width of each of the third coating C3 and the fourth coating C4.

[0130] The portion of the electrode plate CS' coated with the first coating C1' and the second coating C2' (i.e., overlapping with the first coating C1' and the second coating C2') can be referred to as the coated portion, and the portion of the electrode plate CS' not coated with the first coating C1' and the second coating C2' (i.e., spaced apart from the first coating C1' and the second coating C2') can be referred to as the uncoated portion. The uncoated portion of the electrode plate CS' can be an electrode tab PT. The electrode tab PT can be an external connection terminal of the electrode PE. The width of the electrode tab PT can be less than the width of each of the first coating C1' and the second coating C2'.

[0131] (Sixth Implementation Method)

[0132] Figure 10 This is an exploded perspective view of the battery cell 121 according to the embodiment.

[0133] Reference Figure 9 and Figure 10 The battery cell 121 may include a cell housing 121C, an electrode assembly 121EA, a positive terminal 121P, and a negative terminal 121N. The battery cell 121 may also include an electrolyte.

[0134] According to embodiments, battery cell 121 can be a cylindrical battery cell, a prismatic battery cell, or a pouch battery cell. The electrode assembly of a cylindrical battery cell is embedded in a cylindrical metal can. The electrode assembly of a prismatic battery cell is embedded in a prismatic metal can. The electrode assembly of a pouch battery cell is embedded in a pouch housing including aluminum laminates. Hereinafter, the technical concept of this disclosure will be described with reference to an example of battery cell 121 being a pouch battery cell; however, those skilled in the art will be able to readily derive examples of battery cell 121 being a cylindrical or prismatic battery cell based on the description herein.

[0135] Electrode assembly 121EA can be based on Figure 9 The electrode assembly EA is provided. More specifically, the electrode assembly 121EA can be provided by stacking additional electrodes PE and EL and an additional diaphragm SRS on the electrode assembly EA.

[0136] Each electrode PE of electrode assembly 121EA may include an electrode tab PT. The electrode tab PT of each electrode PE of electrode assembly 121EA may be shorted to the negative terminal 121N. The electrode tab PT of each electrode PE of electrode assembly 121EA may be soldered to the negative terminal 121N.

[0137] Each electrode EL of electrode assembly 121EA may include an electrode tab ET. The electrode tab ET of each electrode EL of electrode assembly 121EA may be shorted to the positive terminal 121P. The electrode tab ET of each electrode EL of electrode assembly 121EA may be soldered to the positive terminal 121P.

[0138] The cell housing 121C may include an inner resin layer, a metal layer, and an outer resin layer. An adhesive and an anti-corrosion layer may be further provided between the inner resin layer and the metal layer, and between the outer resin layer and the metal layer.

[0139] The inner resin layer may be thermally adhesive and is referred to as a sealant layer. The inner resin layer allows for sealing of the cell housing 121C. The inner resin layer may include, for example, polyolefin resins such as polypropylene and polyethylene. The metal layer may include alloys of iron, carbon, chromium, and manganese, alloys of iron, chromium, and nickel, or aluminum. The metal layer may serve as a gas barrier. The metal layer can prevent gases from entering and leaving the cell housing 121C. The outer resin layer may be a surface protective layer. The outer resin layer may include materials with abrasion resistance and heat resistance, such as nylon resin.

[0140] The cell housing 121C can be provided by combining a first cell housing 121C1 and a second cell housing 121C2. The first cell housing 121C1 may be substantially flat. The first cell housing 121C1 may not include a receiving portion. The second cell housing 121C2 may include a receiving portion 121R. The receiving portion 121R can be formed by a bag forming process. The receiving portion 121R is a cup-shaped molded portion of the second cell housing 121C2 to receive the electrode assembly 121EA within the receiving portion 121R.

[0141] The step 121T of the second cell housing 121C2 can surround the receiving portion 121R. The step 121T of the second cell housing 121C2 can be joined to the edge of the first cell housing 121C1 to form the cell housing 121C. The sealing portion 121CS can be provided by joining the first housing 121C1 and the second housing 121C2 together. That is, the sealing portion 121CS can be the joining portion of the first housing 121C1 and the second housing 121C2.

[0142] like Figure 2 As shown, when the receiving portion is formed only in the second cell housing 121C2 within the first housing 121C1 and the second housing 121C2, the sealing portion 121CS can be connected to the first main surface 121FS1. The sealing portion 121CS may include a portion coplanar with the first main surface 121FS1.

[0143] The cell housing 121C may have a generally cuboid shape, and the first main surface 121FS1 and the second main surface 121FS2 of the cell housing 121C may be the widest surfaces of the cell housing 121C. The first main surface 121FS1 and the second main surface 121FS2 may be substantially parallel to the electrode assembly 121EA or at least one of a plurality of positive electrodes and a plurality of negative electrodes of the electrode assembly 121EA. The first main surface 121FS1 and the second main surface 121FS2 may be opposite to each other.

[0144] Insulating tape 121I can be applied to the positive terminal 121P and the negative terminal 121N. The positive terminal 121P and the negative terminal 121N can protrude outside the cell housing 121C. Therefore, the voltage and current obtained from the battery cell 121 can be output through the positive terminal 121P and the negative terminal 121N. The positive terminal 121P can be a positive lead. The negative terminal 121N can be a negative lead.

[0145] (Seventh Implementation)

[0146] Figure 11 This is a cross-sectional view of a patterned electrode sheet PES' according to other embodiments.

[0147] Reference Figure 11 The patterned electrode sheet PES' may include a current collector CS, a first coating C1'', and a second coating C2''. The current collector CS may be related to the above-mentioned reference. Figures 1 to 3 The current collectors described are essentially the same, and their repeated descriptions are omitted here.

[0148] The first coating C1'' may include a first active material layer AL1' and a second active material layer AL2''. The first coating C1'' may include a plurality of grooves GV1'. In addition to each of the plurality of grooves GV1' extending over the first active material layer AL1' and the second active material layer AL2'', the first coating C1'' and... Figure 5 The first coating C1' is substantially the same. According to an embodiment, the surface of the first coating C1'' can be patterned to increase the specific surface area of ​​the first coating C1''.

[0149] The depth of each of the plurality of grooves GV1' may be different from the thickness of the second active material layer AL2''. The depth of each of the plurality of grooves GV1' may be greater than the thickness of the second active material layer AL2''.

[0150] The depth of each of the plurality of grooves GV1' may be different from the sum of the thickness of the first active material layer AL1' and the thickness of the second active material layer AL2''. The depth of each of the plurality of grooves GV1' may be less than the sum of the thickness of the first active material layer AL1' and the thickness of the second active material layer AL2''.

[0151] The second coating C2'' may include a third active material layer AL3' and a fourth active material layer AL4''. The second coating C2'' may include a plurality of grooves GV2'. In addition to each of the plurality of grooves GV2' extending over the third active material layer AL3' and the fourth active material layer AL4'', the second coating C2'' is... Figure 5 The second coating C2' is substantially the same. According to an embodiment, the surface of the second coating C2'' can be patterned to increase the specific surface area of ​​the second coating C2''.

[0152] The depth of each of the plurality of grooves GV2' can be different from the thickness of the fourth active material layer AL4''. The depth of each of the plurality of grooves GV2' can be greater than the thickness of the fourth active material layer AL4''.

[0153] The depth of each of the plurality of grooves GV2' may be different from the sum of the thicknesses of the third active material layer AL3' and the fourth active material layer AL4''. The depth of each of the plurality of grooves GV2' may be less than the sum of the thicknesses of the third active material layer AL3' and the fourth active material layer AL4''.

[0154] (Eighth Implementation)

[0155] Figure 12 This is a cross-sectional view used to describe the electrode PE' according to the embodiment.

[0156] Reference Figure 12The electrode PE' may include an electrode plate CS', a first coating C1'', and a second coating C2''. The first coating C1'' may include a first active material layer AL1' and a second active material layer AL2''. The second coating C2' may include a third active material layer AL3 and a fourth active material layer AL4''.

[0157] Electrode PE' can be cut in the transverse direction TD. Figure 11 Patterned electrode sheets (PES') are provided. Electrode plates (CS') can be cut along the transverse direction (TD). Figure 11 The current collector sheet CS is formed. The first active material layer AL1', the second active material layer AL2'', the third active material layer AL3', and the fourth active material layer AL4'' are as described above. Figure 11 The descriptions are essentially the same, so repeated descriptions are omitted here.

[0158] (Ninth Implementation)

[0159] Figure 13 This is a diagram used to describe the secondary battery manufacturing apparatus 1101 according to an embodiment.

[0160] Reference Figure 3 and Figures 1 to 3 The secondary battery manufacturing equipment 1101 may include an unwinder 1111, a rewinder 1113, a first mold coater 1122, a second mold coater 1126, a first magnetization device 1131, a second magnetization device 1133, a first drying device 1141, a second drying device 1143, and a guide roller 1150.

[0161] Unwinder 1111, rewinder 1113, first magnetizing device 1131, second magnetizing device 1133, first drying device 1141, second drying device 1143 and guide roller 1150 are referenced above. ​ The descriptions are essentially the same, therefore, their repetition is omitted here. Each of the first mold coater 1122 and the second mold coater 1126 can be a double-layer mold. The first mold coater 1122 can be configured to form a first active material layer AL1 and a second active material layer AL2 on a first surface CS1 of the current collector sheet CS. A first coating C1 can be formed by the first mold coater 1122. The second mold coater 1126 can be configured to form a third active material layer AL3 and a fourth active material layer AL4 on a second surface CS2 of the current collector sheet CS. A second coating C2 can be formed by the second mold coater 1126.

[0162] The present disclosure has been described in more detail above with reference to the accompanying drawings and embodiments. However, the configurations shown in the drawings or the embodiments described in this specification are merely examples of the present disclosure and do not reflect all the technical concepts of the present disclosure. Therefore, it should be understood that various equivalents and modifications to these configurations may exist at the time of filing this application.

Claims

1. A method for manufacturing a secondary battery, the method comprising the following steps: A first coating is formed on the first surface of the current collector sheet, the first coating comprising a first active material layer and a second active material layer; Magnetize the first active material layer; Dry the first coating; A second coating is formed on a second surface of the current collector opposite to the first surface, the second coating comprising a third active material layer and a fourth active material layer; Magnetize the third active material layer; Dry the second coating; A rolling process is performed on the electrode sheet comprising the current collector, the first coating, and the second coating; as well as The electrode sheet is patterned to form a plurality of grooves in the second active material layer and the fourth active material layer.

2. The method according to claim 1, wherein The electrode sheet is patterned by a patterning roller.

3. The method according to claim 1, wherein The depth of each of the plurality of grooves is less than the thickness of the second active material layer.

4. The method according to claim 1, wherein Each of the plurality of grooves extends along the direction of movement of the electrode sheet.

5. The method according to claim 1, wherein The first active material layer comprises a material different from that of the second active material layer, and The third active material layer comprises a material different from that of the fourth active material layer.

6. The method according to claim 1, wherein Each of the first and third active material layers comprises natural graphite, and Each of the second and fourth active material layers comprises artificial graphite.

7. An electrode, the electrode comprising: Electrode plates; A first active material layer on the first surface of the electrode plate; as well as A second active material layer on top of the first active material layer The second active material layer includes multiple grooves.

8. The electrode according to claim 7, wherein The first active material layer comprises a material different from the material of the second active material layer.

9. The electrode according to claim 7, wherein The remanent magnetization of the first active material layer is different from that of the second active material layer.

10. The electrode according to claim 7, wherein The remanent magnetization of the first active material layer is greater than that of the second active material layer.

11. The electrode according to claim 7, wherein The surface alignment of the first active material layer is different from that of the second active material layer.

12. The electrode according to claim 7, wherein The surface alignment of the first active material layer is higher than that of the second active material layer.

13. The electrode according to claim 7, wherein The first active material layer comprises natural graphite, and The second active material layer comprises artificial graphite.

14. The electrode according to claim 7, wherein The first active material layer is magnetized.

15. The electrode according to claim 7, wherein The depth of each of the plurality of grooves is different from the depth of the second active material layer.

16. The electrode according to claim 7, wherein The depth of each of the plurality of grooves is less than the depth of the second active material layer.

17. The electrode according to claim 7, wherein Each of the plurality of grooves extends along a first direction parallel to the electrode plate.

18. The electrode according to claim 17, wherein The plurality of grooves are spaced apart from each other in a second direction perpendicular to the first direction.

19. The electrode according to claim 7, wherein The depth of each of the plurality of grooves is different from the sum of the thicknesses of the first active material layer and the second active material layer.

20. The electrode according to claim 7, wherein The depth of each of the plurality of grooves is less than the sum of the thickness of the first active material layer and the thickness of the second active material layer.

21. The electrode according to claim 7, wherein Each of the first active material layer and the second active material layer comprises artificial graphite and natural graphite.

22. The electrode according to claim 21, wherein The mass percentage of natural graphite in the first active material layer is different from the mass percentage of natural graphite in the second active material layer.

23. The electrode according to claim 21, wherein The mass percentage of natural graphite in the first active material layer is greater than the mass percentage of natural graphite in the second active material layer.

24. The electrode according to claim 21, wherein The mass percentage of artificial graphite in the first active material layer is different from the mass percentage of artificial graphite in the second active material layer.

25. The electrode according to claim 21, wherein The mass percentage of artificial graphite in the first active material layer is less than the mass percentage of artificial graphite in the second active material layer.

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