Electrode assembly and manufacturing method thereof

Abstract

The technical idea of the present invention provides an electrode assembly comprising: a separator sheet including a folding part folded in a zigzag shape to define a plurality of accommodation spaces separated in the vertical direction, and a cover part extending from the folding part; and a cell structure accommodated in the plurality of accommodation spaces of the separator sheet and including a first electrode and a second electrode, wherein the cover part of the separator sheet includes a first side cover part covering a first side surface of the cell structure, and the first side cover part includes a first through-hole communicating with at least one of the plurality of accommodation spaces of the separator sheet.

Description

Electrode assembly and method for manufacturing the same

[0001] The present invention relates to an electrode assembly and a method for manufacturing the same.

[0002] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2024-0033295, filed on March 8, 2024, and all contents of the document in that Republic of Korea Patent Application are incorporated herein by reference.

[0003] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. They are widely used as an energy source for various wireless devices, including handsets, laptops, and cordless vacuum cleaners. Typically, secondary batteries consist of an electrode assembly, consisting of laminated electrodes and a separator, housed within a pouch-like battery case. If gas traps occur in the electrode assembly, inactive regions form on the electrode surface, leading to lithium precipitation during charging and discharging.

[0004] The technical problem to be solved by the present invention is to provide an electrode assembly and a method for manufacturing the same.

[0005] In order to solve the above-described problem, the technical idea of ​​the present invention provides an electrode assembly including a separator sheet including a folding portion folded in a zigzag shape to define a plurality of accommodation spaces separated in a vertical direction and a cover portion extending from the folding portion; and a cell structure accommodated in the plurality of accommodation spaces of the separator sheet and including a first electrode and a second electrode; wherein the cover portion of the separator sheet includes a first side cover portion covering a first side surface of the cell structure, and the first side cover portion includes a first through hole communicating with at least one of the plurality of accommodation spaces of the separator sheet.

[0006] In exemplary embodiments, the cover portion of the separator sheet further includes a second side cover portion covering a second side of the cell structure opposite to the first side of the cell structure, wherein the second side cover portion includes a second through hole communicating with at least one of the plurality of receiving spaces of the separator sheet.

[0007] In exemplary embodiments, the cover portion of the separator sheet further includes a third side cover portion contacting the first side cover portion, and the third side cover portion includes a third through hole communicating with the first through hole.

[0008] In exemplary embodiments, the cover portion of the separator sheet is characterized in that it further includes a first bottom cover portion extending between the first side cover portion and the second side cover portion and covering a bottom surface of the cell structure; and a top cover portion extending between the second side cover portion and the third side cover portion and covering an upper surface of the cell structure.

[0009] In exemplary embodiments, the cover portion of the separator sheet further includes a second bottom cover portion connected to the third side cover portion, wherein the second bottom cover portion is fixed to the first bottom cover portion.

[0010] In exemplary embodiments, the separator sheet is characterized as being a single sheet.

[0011] In exemplary embodiments, the cell structure comprises a plurality of unit cells spaced apart from each other by the folding portion of the separator sheet, each of the plurality of unit cells comprising at least one of the first electrode and the second electrode.

[0012] In exemplary embodiments, in the cell structure, the first electrode is characterized as being a single sheet extending in a zigzag shape along the folding portion of the separator sheet.

[0013] In exemplary embodiments, in the cell structure, the second electrode is characterized as a single sheet extending in a zigzag shape along the first electrode.

[0014] In order to solve the above-described problem, the technical idea of ​​the present invention provides a method for manufacturing an electrode assembly, including the steps of preparing a structure including a separator sheet and a cell structure, wherein the cell structure includes a first electrode and a second electrode, and the separator sheet includes a folding portion defining a plurality of accommodation spaces for accommodating the cell structure and a cover portion connected to the folding portion; a first punching step of forming a first through hole in a first side cover portion of the cover portion of the separator sheet; and a first winding step of winding the cover portion of the separator sheet so that the first side cover portion of the separator sheet faces a first side surface of the cell structure.

[0015] In exemplary embodiments, the first winding step is characterized by further comprising a step of winding the cover portion of the separator sheet such that the first bottom cover portion of the cover portion of the separator sheet connected to the first side cover portion of the separator sheet faces the bottom surface of the cell structure.

[0016] In exemplary embodiments, the method further comprises a second punching step of forming a second through hole in the second side cover portion of the cover portion of the separator sheet; and a second winding step of winding the cover portion of the separator sheet so that the second side cover portion of the separator sheet faces the second side of the cell structure.

[0017] In exemplary embodiments, the second winding step is characterized by further comprising a step of winding the cover portion of the separator sheet so that the top cover portion of the cover portion of the separator sheet connected to the second side cover portion of the separator sheet faces the upper surface of the cell structure.

[0018] In exemplary embodiments, the method further includes a third punching step of forming a third through hole in a third side cover portion of the cover portion of the separator sheet; and a third winding step of winding the cover portion of the separator sheet so that the third side cover portion of the separator sheet contacts the first side cover portion of the cover portion of the separator sheet; wherein the first through hole provided in the first side cover portion of the separator sheet is aligned with the third through hole provided in the third side cover portion of the separator sheet.

[0019] In exemplary embodiments, the first winding step further comprises a step of winding the cover portion of the separator sheet so that the first bottom cover portion of the cover portion of the separator sheet connected to the first side cover portion of the separator sheet faces the bottom surface of the cell structure, and the third winding step further comprises a step of winding the cover portion of the separator sheet so that the second bottom cover portion of the cover portion of the separator sheet connected to the third side cover portion of the separator sheet contacts the first bottom cover portion of the separator sheet.

[0020] According to exemplary embodiments, the separator sheet of the electrode assembly includes a gas exhaust hole for exhausting gas within the electrode assembly, so that gas within the electrode assembly can be quickly exhausted to the outside of the electrode assembly during a degassing process, and gas trapping within the electrode assembly can be prevented or suppressed. Accordingly, capacity reduction, increased cell resistance, lithium precipitation, etc. due to gas trapping within the electrode assembly can be prevented, and ultimately, the reliability of a secondary battery including the electrode assembly can be improved.

[0021] According to exemplary embodiments, after the punching process for forming a through hole in the cover portion of the separator sheet is completed, a winding process for winding the cover portion of the separator sheet is performed, thereby preventing damage to the unit cell during the punching process.

[0022] The effects that can be 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 skilled in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects resulting from practicing the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0023] FIG. 1 is a perspective view showing an electrode assembly according to exemplary embodiments.

[0024] FIG. 2 is a cross-sectional view showing an electrode assembly according to exemplary embodiments.

[0025] FIG. 3 is a cross-sectional view showing a portion of a cell structure of an electrode assembly according to exemplary embodiments.

[0026] FIG. 4 is a flowchart illustrating a method for manufacturing an electrode assembly according to exemplary embodiments.

[0027] FIGS. 5 to 11 are drawings showing a method of manufacturing an electrode assembly according to exemplary embodiments.

[0028] Fig. 12 is a cross-sectional view showing a method for manufacturing an electrode assembly according to exemplary embodiments.

[0029] FIG. 13 is a cross-sectional view showing an electrode assembly according to exemplary embodiments.

[0030] FIG. 14 is a cross-sectional view showing an electrode assembly according to exemplary embodiments.

[0031] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that aligns with the technical spirit of the present invention.

[0032] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0033] In addition, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description is omitted.

[0034] Since the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, the shapes and sizes of components in the drawings may be exaggerated, omitted, or schematically illustrated for clearer explanation. Accordingly, the sizes and proportions of each component do not fully reflect the actual sizes or proportions.

[0035]

[0036] (Example 1)

[0037] FIG. 1 is a perspective view illustrating an electrode assembly (100) according to exemplary embodiments. FIG. 2 is a cross-sectional view illustrating an electrode assembly (100) according to exemplary embodiments. FIG. 3 is a cross-sectional view illustrating a portion of a cell structure (110) of an electrode assembly (100) according to exemplary embodiments.

[0038] Referring to FIGS. 1 to 3, the electrode assembly (100) may include a cell structure (110) and a separator sheet (120).

[0039] The cell structure (110) can constitute a secondary battery. The cell structure (110) can include a first electrode (191), a second electrode (192), or a laminate in which at least one first electrode (191) and at least one second electrode (192) are vertically stacked (e.g., in the Z direction) by a separator (193). The separator (193) may also be referred to as an internal separator. Here, the first electrode (191) and the second electrode (192) may have opposite polarities. For example, the first electrode (191) may be a positive electrode, and the second electrode (192) may be a negative electrode. Alternatively, the first electrode (191) may be a negative electrode, and the second electrode (192) may be a positive electrode. The positive electrode may include a positive electrode current collector and a positive electrode active material. The negative electrode may include a negative electrode current collector and a negative electrode active material. The cell structure (110) may include electrode tabs (119) connected to at least one anode and / or at least one cathode.

[0040] In exemplary embodiments, the cell structure (110) may include a plurality of unit cells (111) stacked in a vertical direction (e.g., in the Z direction). Each of the plurality of unit cells (111) may be a single first electrode (191), a single second electrode (192), or a stack in which at least one first electrode (191) and at least one second electrode (192) are stacked in a vertical direction (e.g., in the Z direction) by a separator (193). In exemplary embodiments, each unit cell (111) may include a bi-cell or a mono-cell. A bi-cell may have a laminated structure in which the two outermost electrodes have the same types, such as anode / separator / cathode / separator / anode, anode / separator / cathode / separator / anode / separator / anode / separator / anode, cathode / separator / anode / separator / anode / separator / anode, cathode / separator / anode / separator / anode / separator / anode / separator / anode / separator / anode / separator / anode. A mono-cell may have a laminated structure in which the two outermost electrodes have different types, such as anode / separator / cathode, anode / separator / cathode / separator / anode / separator / anode / separator / anode.

[0041] The unit cell (111) may generally have a flat plate shape extending in a first horizontal direction (e.g., X direction) and a second horizontal direction (e.g., Y direction). The unit cell (111) may have a top surface and a bottom surface opposite to each other in a vertical direction (e.g., Z direction), a first side surface and a second side surface opposite to each other in a first horizontal direction (e.g., X direction), and a front surface and a back surface opposite to each other in a second horizontal direction (e.g., Y direction). The electrode tab (119) may be provided on the front surface and / or the back surface of the unit cell (111). The top surface and the bottom surface of the unit cell (111) may be flat plates extending in the first horizontal direction (e.g., X direction) and the second horizontal direction (e.g., Y direction), respectively, and may be in contact with the separator sheet (120). At this time, the cell structure (110) may have a top surface and a bottom surface that are opposed in a vertical direction (e.g., Z direction), a first side surface and a second side surface that are opposed in a first horizontal direction (e.g., X direction), and a front surface and a back surface that are opposed in a second horizontal direction (e.g., Y direction). A first side (1151) of the cell structure (110) may include first side surfaces of a plurality of unit cells (111), a second side (1153) of the cell structure (110) may include second side surfaces of a plurality of unit cells (111), a top surface (1154) of the cell structure (110) may include a top surface of an uppermost unit cell (111) among the plurality of unit cells (111), a bottom surface (1152) of the cell structure (110) may include a bottom surface of a lowermost unit cell (111) among the plurality of unit cells (111), a front surface of the cell structure (110) may include front surfaces of the plurality of unit cells (111), and a back surface of the cell structure (110) may include back surfaces of the plurality of unit cells (111). A unit cell (111) may have a short axis parallel to a first horizontal direction (e.g., X direction) and a long axis parallel to a second horizontal direction (e.g., Y direction).That is, the length of the unit cell (111) along the first horizontal direction (e.g., X direction) may be smaller than the length of the unit cell (111) along the second horizontal direction (e.g., Y direction).

[0042] The separator sheet (120) may include a folding portion (130) and a cover portion (140). The separator sheet (120) may be a single sheet.

[0043] The folding member (130) may be extended and bent in a zigzag shape to define a plurality of receiving spaces (131) separated in a vertical direction (e.g., Z direction). A unit cell (111) may be arranged in each of the plurality of receiving spaces (131) of the folding member (130). The folding member (130) may surround an individual unit cell (111), and the plurality of unit cells (111) may be spaced apart from each other by the folding member (130). Two adjacent unit cells (111) among the plurality of unit cells (111) may be spaced apart with a portion of the folding member (130) therebetween. The folding member (130) may cover the top surface, the bottom surface, and one side surface of the individual unit cell (111), but may not cover the other side surface, the front surface, and the back surface of the individual unit cell (111). For example, a plurality of unit cells (111) may include unit cells (111) in odd layers and unit cells (111) in even layers. The folding portion (130) may extend along the bottom surface, the first side surface, and the top surface of each of the unit cells (111) in the odd layers, and the second side surface, the front surface, and the back surface of each of the unit cells (111) in the odd layers may not be covered by the folding portion (130). The folding portion (130) may extend along the bottom surface, the second side surface, and the top surface of each of the unit cells (111) in the even layers, and the first side surface, the front surface, and the back surface of each of the unit cells (111) in the even layers.

[0044] The cover portion (140) extends from the folding portion (130) and can be rolled up to surround the cell structure (110) and the folding portion (130). The cover portion (140) can be rolled up to surround the cell structure (110) to form an internal space that accommodates the cell structure (110). The cover portion (140) can be connected to the folding portion (130). For example, the folding portion (130) can be connected to a portion of the folding portion (130) that is in contact with the upper surface of the uppermost unit cell (111), and can be rolled up to cover the first side surface (1151), the bottom surface, the second side surface, and the upper surface of the cell structure (110).

[0045] In exemplary embodiments, the cover portion (140) includes a first side cover portion (141) facing a first side surface (1151) of the cell structure (110) and at least partially covering the first side surface (1151) of the cell structure (110), a first bottom cover portion (142) facing a bottom surface (1152) of the cell structure (110) and at least partially covering the bottom surface (1152) of the cell structure (110), a second side cover portion (143) facing a second side surface (1153) of the cell structure (110) and at least partially covering the second side surface (1153) of the cell structure (110), a top cover portion (144) facing a top surface (1154) of the cell structure (110) and at least partially covering the top surface (1154) of the cell structure (110), and a first side cover portion (141) that is in contact with the first side cover portion (141) and at least partially covering the first side surface (1151) of the cell structure (110). It may include a third side cover part (145) that at least partially covers the cover part (141), and a second bottom cover part (146) that is in contact with the first bottom cover part (142). The second bottom cover part (146) may be fixed to the first bottom cover part (142) by a tape (160). The first side cover part (141), the first bottom cover part (142), the second side cover part (143), the top cover part (144), the third side cover part (145), and the second bottom cover part (146) may be sequentially arranged between the folding part (130) and the end of the separator sheet (120).

[0046] The cover portion (140) of the separator sheet (120) may include a gas discharge hole for communicating between the inner space of the cover portion (140) in which the cell structure (110) is accommodated and the outer space on the outside of the cover portion (140). In exemplary embodiments, the first side cover portion (141) may include a first through hole (151), the second side cover portion (143) may include a second through hole (152), and the third side cover portion (145) may include a third through hole (153). The first through hole (151) of the first side cover part (141), the second through hole (152) of the second side cover part (143), and the third through hole (153) of the third side cover part (145) may each be connected to at least one of the plurality of accommodation spaces (131) provided by the folding part (130) of the separator sheet (120). The first through hole (151) of the first side cover part (141), the second through hole (152) of the second side cover part (143), and the third through hole (153) of the third side cover part (145) may constitute a gas discharge hole of the separator sheet (120). The first through hole (151) of the first side cover part (141) may be connected to the third through hole (153) of the third side cover part (145). Gas around the electrode assembly (100) can be discharged to the outside of the electrode assembly (100) through the first through hole (151) of the first side cover part (141) and the third through hole (153) of the third side cover part (145), and can be discharged to the outside of the electrode assembly (100) through the second through hole (152) of the second side cover part (143).

[0047] The first side cover portion (141) may include a plurality of first through holes (151). For example, the plurality of first through holes (151) may be arranged in a second horizontal direction (e.g., Y direction). For example, the plurality of first through holes (151) may be arranged to have a plurality of rows and a plurality of columns. The second side cover portion (143) may include a plurality of second through holes (152). For example, the plurality of second through holes (152) may be arranged in a second horizontal direction (e.g., Y direction). For example, the plurality of second through holes (152) may be arranged to have a plurality of rows and a plurality of columns. The third side cover portion (145) may include a plurality of third through holes (153). For example, the plurality of third through holes (153) may be arranged in a second horizontal direction (e.g., Y direction). For example, the plurality of third through holes (153) can be arranged to have a plurality of rows and a plurality of columns.

[0048] In order to manufacture a secondary battery including the electrode assembly (100), an insertion process for storing the electrode assembly (100) in a battery case such as a pouch, an electrolyte injection process for injecting an electrolyte into the battery case, a charge / discharge process for the electrode assembly (100), a degassing process for removing internal gas within the electrode assembly (100), and a sealing process for sealing the battery case can be performed. If the internal gas of the electrode assembly (100) is not removed during the degassing process, a gas trap occurs within the electrode assembly (100), and the gas trap causes a decrease in capacity, an increase in cell resistance, lithium precipitation, etc., thereby lowering the reliability of the secondary battery.

[0049] According to exemplary embodiments, the separator sheet (120) of the electrode assembly (100) includes a gas discharge hole for discharging gas within the electrode assembly (100), so that gas within the electrode assembly (100) can be quickly discharged to the outside of the electrode assembly (100) during a degassing process, and gas traps can be prevented or suppressed from occurring within the electrode assembly (100). Accordingly, capacity reduction, increased cell resistance, lithium precipitation, etc. due to gas traps within the electrode assembly (100) can be prevented, and ultimately, the reliability of a secondary battery including the electrode assembly (100) can be improved.

[0050]

[0051] (Example 2)

[0052] FIG. 4 is a flowchart illustrating a method for manufacturing an electrode assembly (100) according to exemplary embodiments. FIGS. 5 to 11 are drawings illustrating a method for manufacturing an electrode assembly (100) according to exemplary embodiments. FIGS. 5, 6a, 7, 8a, 9, 10a, and 11 are cross-sectional views illustrating a method for manufacturing an electrode assembly (100), and FIGS. 6b, 8b, and 10b are plan views illustrating a method for manufacturing an electrode assembly (100). Hereinafter, a method for manufacturing an electrode assembly (100) illustrated in FIGS. 1 to 3 will be described with reference to FIGS. 4 to 11.

[0053] Referring to FIG. 5, a structure (100p) including a plurality of unit cells (111) and a separator sheet (120) is prepared (S110). In the structure (100p), the separator sheet (120) may include a folding part (130) folded in a zigzag shape to surround each of the plurality of unit cells (111), and a cover part (140) connected to the folding part (130).

[0054] Referring to FIGS. 6A and 6B, the structure (100p of FIG. 5) is fed into a secondary battery manufacturing device configured to perform a punching process for a cover portion (140) of a separator sheet (120) and a winding process for the cover portion (140) of the separator sheet (120). The secondary battery manufacturing device may include a holder (210) configured to support the cell structure (110), a gripper (220) configured to hold and support an end of the cover portion (140) of the separator sheet (120), and a cutter (230) configured to punch the cover portion (140) of the separator sheet (120). The holder (210) may include a holding block that holds the cell structure (110) and an actuator that moves the holding block. The gripper (220) may include a gripper block that grips an end of a cover portion (140) of a membrane sheet (120) and an actuator that moves the gripper block. The cutter (230) may be configured to cut the cover portion (140) of the membrane sheet (120) to form a through hole in the membrane sheet (120). In exemplary embodiments, the cutter (230) may include at least one needle (231). The needle (231) may move to penetrate the cover portion (140) of the membrane sheet (120) to form a through hole in the cover portion (140) of the membrane sheet (120).

[0055] When the structure (100p) is inserted into the secondary battery manufacturing device, the secondary battery manufacturing device performs a first punching process to form a first through hole (151) in the first side cover portion (141) of the separator sheet (120) (S120).

[0056] In the above step S120, the holder (210) can support the cell structure (110), and the gripper (220) can support the cover part (140) of the membrane sheet (120). The gripper (220) can support the cover part (140) of the membrane sheet (120) so that the first side cover part (141) of the membrane sheet (120) does not cover the first side (1151) of the cell structure (110). For example, the gripper (220) can support the cover part (140) of the membrane sheet (120) so that the first side cover part (141) of the membrane sheet (120) extends in a first horizontal direction (e.g., X direction).

[0057] In the above step S120, while the gripper (220) supports the cover portion (140) of the membrane sheet (120), the cutter (230) can form a first through hole (151) in the first side cover portion (141) of the membrane sheet (120) connected to the folding portion (130) of the membrane sheet (120). For example, the cutter (230) can move the needle (231) in a vertical direction (e.g., Z direction) so that the needle (231) penetrates the first side cover portion (141) of the membrane sheet (120), thereby forming a first through hole (151) in the first side cover portion (141) of the membrane sheet (120). The above cutter (230) can form a plurality of first through holes (151) arranged in a second horizontal direction (e.g., Y direction) in the first side cover portion (141) of the separator sheet (120).

[0058] Referring to FIG. 7, after the first punching process is completed, the secondary battery manufacturing device performs a first winding process of winding the cover part (140) of the separator sheet (120) so that the first side cover part (141) of the separator sheet (120) covers the first side (1151) of the cell structure (110) and the first bottom cover part (142) of the separator sheet (120) covers the bottom surface (1152) of the cell structure (110) (S130).

[0059] In the above step S130, the first side cover portion (141) of the separator sheet (120) faces the first side surface (1151) of the cell structure (110) and can contact a portion of the folding portion (130) extending along the first side surface (1151) of the cell structure (110). In addition, the first bottom cover portion (142) of the separator sheet (120) can contact a portion of the folding portion (130) extending along the bottom surface (1152) of the cell structure (110).

[0060] In the above step S130, winding the cover part (140) of the membrane sheet (120) about the cell structure (110) can be achieved by relative rotation between the cover part (140) of the membrane sheet (120) and the cell structure (110). In exemplary embodiments, the first winding process can be achieved by rotating the holder (210) holding the cell structure (110) and the folding part (130) about a rotation axis parallel to a second horizontal direction (e.g., Y direction) while the gripper (220) fixes the cover part (140) of the membrane sheet (120). In exemplary embodiments, the first winding process can be achieved by the gripper (220) moving such that the first side cover portion (141) and the first bottom cover portion (142) of the separator sheet (120) surround the cell structure (110) while the holder (210) holds the cell structure (110) and the folding portion (130).

[0061] Referring to FIGS. 8a and 8b, after the first winding process is completed, the secondary battery manufacturing device performs a second punching process to form a second through hole (152) in the second side cover portion (143) of the separator sheet (120) (S140).

[0062] In the above step S140, while the holder (210) supports the cell structure (110), the gripper (220) can support the cover portion (140) of the membrane sheet (120) so that the second side cover portion (143) of the membrane sheet (120) does not cover the second side (1153) of the cell structure (110). For example, the gripper (220) can support the cover portion (140) of the membrane sheet (120) so that the second side cover portion (143) of the membrane sheet (120) extends in the first horizontal direction (e.g., the X direction).

[0063] In the above step S140, while the gripper (220) supports the cover portion (140) of the membrane sheet (120), the cutter (230) can form a second through hole (152) in the second side cover portion (143) of the membrane sheet (120) connected to the first bottom cover portion (142) of the membrane sheet (120). For example, the cutter (230) can move the needle (231) in a vertical direction (e.g., Z direction) so that the needle (231) penetrates the second side cover portion (143) of the membrane sheet (120), thereby forming a second through hole (152) in the second side cover portion (143) of the membrane sheet (120). The above cutter (230) can form a plurality of second through holes (152) arranged in a second horizontal direction (e.g., Y direction) in the second side cover portion (143) of the separator sheet (120).

[0064] Referring to FIG. 9, after the second punching process is completed, the secondary battery manufacturing device performs a second winding process of winding the cover part (140) of the separator sheet (120) so that the second side cover part (143) of the separator sheet (120) covers the second side (1153) of the cell structure (110) and the top cover part (144) of the separator sheet (120) covers the upper surface (1154) of the cell structure (110) (S150).

[0065] In the above step S150, the second side cover portion (143) of the separator sheet (120) faces the second side surface (1153) of the cell structure (110) and can contact a portion of the folding portion (130) extending along the second side surface (1153) of the cell structure (110). In addition, the top cover portion (144) of the separator sheet (120) can contact a portion of the folding portion (130) extending along the upper surface (1154) of the cell structure (110).

[0066] In the above step S150, winding the cover part (140) of the membrane sheet (120) about the cell structure (110) can be achieved by relative rotation between the cover part (140) of the membrane sheet (120) and the cell structure (110). In exemplary embodiments, the second winding process can be achieved by rotating the holder (210) holding the cell structure (110) and the folding part (130) about a rotation axis parallel to a second horizontal direction (e.g., Y direction) while the gripper (220) fixes the cover part (140) of the membrane sheet (120). In exemplary embodiments, the second winding process may be achieved by the gripper (220) moving such that the second side cover portion (143) and the top cover portion (144) of the separator sheet (120) surround the cell structure (110) while the holder (210) holds the cell structure (110) and the folding portion (130).

[0067] Referring to FIGS. 10a and 10b, after the second winding process is completed, the secondary battery manufacturing device performs a third punching process to form a third through hole (153) in the third side cover portion (145) of the separator sheet (120) (S160).

[0068] In the above step S160, while the holder (210) supports the cell structure (110), the gripper (220) can support the cover portion (140) of the membrane sheet (120) so that the third side cover portion (145) of the membrane sheet (120) does not cover the first side (1151) of the cell structure (110) and the first side cover portion (141) of the membrane sheet (120). For example, the gripper (220) can support the cover portion (140) of the membrane sheet (120) so that the third side cover portion (145) of the membrane sheet (120) extends in the first horizontal direction (e.g., the X direction).

[0069] In the above step S160, while the gripper (220) supports the cover portion (140) of the membrane sheet (120), the cutter (230) can form a third through hole (153) in the third side cover portion (145) of the membrane sheet (120) connected to the top cover portion (144) of the membrane sheet (120). For example, the cutter (230) can move the needle (231) in the vertical direction (e.g., the Z direction) so that the needle (231) penetrates the third side cover portion (145) of the membrane sheet (120), thereby forming the third through hole (153) in the third side cover portion (145) of the membrane sheet (120). The above cutter (230) can form a plurality of third through holes (153) arranged in a second horizontal direction (e.g., Y direction) in the third side cover portion (145) of the separator sheet (120).

[0070] Referring to FIG. 11, after the third punching process is completed, the secondary battery manufacturing device performs a third winding process of winding the cover part (140) of the separator sheet (120) so that the third side cover part (145) of the separator sheet (120) contacts the first side cover part (141) of the separator sheet (120) and the second bottom cover part (146) of the separator sheet (120) contacts the first bottom cover part (142) of the separator sheet (120) (S170).

[0071] In the above step S170, the third side cover part (145) of the separator sheet (120) can cover the first side cover part (141) of the separator sheet (120). The third through hole (153) of the third side cover part (145) can be connected to the first through hole (151) of the first side cover part (141). In addition, the second bottom cover part (146) of the separator sheet (120) can be in contact with the first bottom cover part (142) of the separator sheet (120).

[0072] In the above step S170, winding the cover part (140) of the membrane sheet (120) about the cell structure (110) can be achieved by relative rotation between the cover part (140) of the membrane sheet (120) and the cell structure (110). In exemplary embodiments, the third winding process can be achieved by rotating the holder (210) holding the cell structure (110) and the folding part (130) about a rotation axis parallel to the second horizontal direction (e.g., Y direction) while the gripper (220) fixes the cover part (140) of the membrane sheet (120). In exemplary embodiments, the third winding process may be achieved by the gripper (220) moving such that the third side cover portion (145) and the second bottom cover portion (146) of the separator sheet (120) surround the cell structure (110) while the holder (210) holds the cell structure (110) and the folding portion (130).

[0073] Referring to Fig. 1, after the third winding process is completed, the end of the cover portion (140) of the separator sheet (120) is fixed with tape (160) (S180). In step S180, the second bottom cover portion (146) is fixed to the first bottom cover portion (142) by tape (160).

[0074] In a method for manufacturing an electrode assembly according to a comparative example, after the entire cover portion of the separator sheet is rolled up so that the cover portion of the separator sheet surrounds the cell structure, through holes for gas discharge are formed on both sides of the separator sheet. In this case, there is a concern that the unit cell positioned adjacent to the cover portion of the separator sheet may be damaged by the cutter during the process of cutting the separator sheet with a cutter.

[0075] According to exemplary embodiments, after the punching process for forming a through hole in the cover portion (140) of the separator sheet (120) is completed, a winding process for winding the cover portion (140) of the separator sheet (120) is performed, thereby preventing the unit cell (111) from being damaged during the punching process.

[0076]

[0077] (Example 3)

[0078] FIG. 12 is a cross-sectional view showing a method for manufacturing an electrode assembly (100) according to exemplary embodiments.

[0079] Referring to FIG. 12, in a secondary battery manufacturing device configured to manufacture an electrode assembly (100), a cutter (230a) may include a laser cutter configured to emit a laser beam (233). The cutter (230a) may irradiate the laser beam (233) to the cover portion (140) of the separator sheet (120) to form a through hole in the cover portion (140) of the separator sheet (120). According to exemplary embodiments, after the punching process for forming the through hole in the cover portion (140) of the separator sheet (120) is completed, a winding process for winding the cover portion (140) of the separator sheet (120) is performed, so that the unit cell (111) can be prevented from being damaged by the laser beam (233) in the process of forming the through hole in the separator sheet (120) by irradiating the laser beam (233).

[0080]

[0081] (Example 4)

[0082] Fig. 13 is a cross-sectional view illustrating an electrode assembly (100A) according to exemplary embodiments. Hereinafter, the electrode assembly (100A) illustrated in Fig. 13 will be described, focusing on differences from the electrode assembly (100) described with reference to Figs. 1 to 3.

[0083] Referring to FIG. 13, the electrode assembly (100A) may include a cell structure (110A) and a separator sheet (120) having a folding portion (130) and a cover portion (140). The folding portion (130) of the separator sheet (120) may be folded and extended multiple times in a zigzag shape to define a plurality of vertically separated accommodation spaces (131), and the cell structure (110A) may be accommodated within the plurality of accommodation spaces (131) of the folding portion (130). The cover portion (140) of the separator sheet (120) may surround the cell structure (110A) and the folding portion (130).

[0084] The cell structure (110A) may include a first electrode (191), a second electrode (192), and an internal separator (193). The internal separator (193) may be interposed between the first electrode (191) and the second electrode (192). The first electrode (191) may be extended by being folded in a zigzag shape along the folding portion (130) of the separator sheet (120). The first electrode (191) may be a single sheet. The second electrode (192) may be extended by being folded in a zigzag shape along the folding portion (130) of the first electrode (191) or the separator sheet (120). The second electrode (192) may be a single sheet. The internal separator (193) may be interposed between the first electrode (191) and the second electrode (192). The inner separator (193) may be folded and extended in a zigzag shape along the folding portion (130) of the first electrode (191) or the separator sheet (120). The inner separator (193) may be a single sheet.

[0085] The method for manufacturing the electrode assembly (100A) may include a first step of preparing a first structure in which a separator sheet (120), a first electrode (191), an internal separator (193), and a second electrode (192) are sequentially laminated, a second step of forming a second structure in which the first structure is folded in a zigzag shape, and a third step of surrounding the cell structure (110A) with the cover portion (140) of the separator sheet (120) by repeating the punching process and the winding process for the cover portion (140) of the separator sheet (120) several times. In the second step, as the first structure is folded in a zigzag shape, the folding portion (130) of the separator sheet (120) can be folded in a zigzag shape to have a plurality of accommodation spaces (131) that accommodate the cell structure (110A), and the folding portion (130) of the separator sheet (120), the first electrode (191), the inner separator (193), and the second electrode (192) can each be folded in a zigzag shape. The third step may include steps S120 to S180 of FIG. 4.

[0086]

[0087] (Example 5)

[0088] Fig. 14 is a cross-sectional view illustrating an electrode assembly (100B) according to exemplary embodiments. Hereinafter, the electrode assembly (100B) illustrated in Fig. 14 will be described, focusing on differences from the electrode assembly (100A) described with reference to Fig. 13.

[0089] Referring to FIG. 14, in the electrode assembly (100B), the folding portion (130) of the separator sheet (120) can be folded and extended multiple times in a zigzag shape to define a plurality of vertically separated accommodation spaces (131), and the cell structure (110B) can be accommodated within the plurality of accommodation spaces (131) of the folding portion (130).

[0090] The cell structure (110B) may include a first electrode (191), an inner separator (193), and a plurality of second electrodes (192). The first electrode (191) and the inner separator (193) are each a single sheet, and may be bent and extended in a zigzag shape along the folding portion (130) of the separator sheet (120). Some of the plurality of second electrodes (192) may be accommodated in some of the plurality of accommodation spaces (131) of the folding portion (130), and other of the plurality of second electrodes (192) may be accommodated in other of the plurality of accommodation spaces (131) of the folding portion (130). The inner separator (193) may contact the upper and lower surfaces of some of the plurality of second electrodes (192), and the separator sheet (120) may contact the upper and lower surfaces of other of the plurality of second electrodes (192). Some of the plurality of second electrodes (192) may be separated from the segments of the first electrode (191) disposed above and below them by an inner separator (193), and other of the plurality of second electrodes (192) may be separated from other segments of the first electrode (191) disposed above and below them by a separator sheet (120).

[0091] The method for manufacturing the electrode assembly (100B) may include a first step of preparing a third structure in which a separator sheet (120), a first electrode (191), and an internal separator (193) are sequentially laminated, a second step of forming a fourth structure by bending the third structure in a zigzag shape and arranging a plurality of second electrodes (192) between spaces formed by bending the third structure in a zigzag shape, and a third step of surrounding the cell structure (110B) with the cover portion (140) of the separator sheet (120) by repeating the punching process and the winding process for the cover portion (140) of the separator sheet (120) several times. In the second step, as the third structure is folded in a zigzag shape, the folding portion (130) of the separator sheet (120) can be folded in a zigzag shape to have a plurality of accommodation spaces (131), and the folding portion (130) of the separator sheet (120), the first electrode (191), and the inner separator (193) can each be folded in a zigzag shape. The third step may include steps S120 to S180 of FIG. 4.

[0092]

[0093] The present invention has been described in more detail through drawings and examples. However, the configurations described in the drawings or examples described in this specification are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as of the time of this application.

Claims

1. A separator sheet including a folding portion folded in a zigzag shape to define a plurality of vertically separated receiving spaces and a cover portion extending from the folding portion; and A cell structure accommodated in the plurality of accommodation spaces of the above separator sheet and including a first electrode and a second electrode; Including, An electrode assembly wherein the cover portion of the separator sheet includes a first side cover portion covering a first side of the cell structure, and the first side cover portion includes a first through hole communicating with at least one of the plurality of accommodation spaces of the separator sheet.

2. In paragraph 1, An electrode assembly characterized in that the cover portion of the separator sheet further includes a second side cover portion covering a second side of the cell structure opposite to the first side of the cell structure, and the second side cover portion includes a second through hole communicating with at least one of the plurality of accommodation spaces of the separator sheet.

3. In paragraph 2, An electrode assembly characterized in that the cover portion of the separator sheet further includes a third side cover portion that contacts the first side cover portion, and the third side cover portion includes a third through hole that communicates with the first through hole.

4. In paragraph 3, The cover part of the above separator sheet, A first bottom cover portion extending between the first side cover portion and the second side cover portion and covering the bottom surface of the cell structure; and A top cover portion extending between the second side cover portion and the third side cover portion and covering the upper surface of the cell structure; An electrode assembly characterized by further including:

5. In paragraph 4, An electrode assembly characterized in that the cover portion of the separator sheet further includes a second bottom cover portion connected to the third side cover portion, and the second bottom cover portion is fixed to the first bottom cover portion.

6. In paragraph 1, An electrode assembly characterized in that the above separator sheet is a single sheet.

7. In paragraph 1, An electrode assembly, characterized in that the cell structure includes a plurality of unit cells spaced apart from each other by the folding portion of the separator sheet, and each of the plurality of unit cells includes at least one of the first electrode and the second electrode.

8. In paragraph 1, An electrode assembly characterized in that in the above cell structure, the first electrode is a single sheet extending in a zigzag shape along the folding portion of the separator sheet.

9. In paragraph 8, An electrode assembly characterized in that in the above cell structure, the second electrode is a single sheet extending in a zigzag shape along the first electrode.

10. A step of preparing a structure including a separator sheet and a cell structure, wherein the cell structure includes a first electrode and a second electrode, and the separator sheet includes a folding portion defining a plurality of accommodation spaces for accommodating the cell structure, and a cover portion connected to the folding portion; A first punching step of forming a first through hole in the first side cover portion of the cover portion of the above separator sheet; and A first winding step of winding the cover portion of the separator sheet so that the first side cover portion of the separator sheet faces the first side of the cell structure; A method for manufacturing an electrode assembly comprising:

11. In paragraph 10, A method for manufacturing an electrode assembly, characterized in that the first winding step further includes a step of winding the cover part of the separator sheet so that the first bottom cover part of the cover part of the separator sheet connected to the first side cover part of the separator sheet faces the bottom surface of the cell structure.

12. In paragraph 10, A second punching step of forming a second through hole in the second side cover portion of the cover portion of the above separator sheet; and A second winding step of winding the cover portion of the separator sheet so that the second side cover portion of the separator sheet faces the second side of the cell structure; A method for manufacturing an electrode assembly, characterized in that it further includes.

13. In paragraph 12, A method for manufacturing an electrode assembly, characterized in that the second winding step further includes a step of winding the cover part of the separator sheet so that the top cover part of the cover part of the separator sheet connected to the second side cover part of the separator sheet faces the upper surface of the cell structure.

14. In paragraph 12, A third punching step of forming a third through hole in the third side cover portion of the cover portion of the above separator sheet; and A third winding step of winding the cover part of the separator sheet so that the third side cover part of the separator sheet comes into contact with the first side cover part of the cover part of the separator sheet; Including more, A method for manufacturing an electrode assembly, characterized in that the first through hole provided in the first side cover portion of the separator sheet is aligned with the third through hole provided in the third side cover portion of the separator sheet.

15. In paragraph 14, The first winding step further includes a step of winding the cover part of the separator sheet so that the first bottom cover part of the cover part of the separator sheet connected to the first side cover part of the separator sheet faces the bottom surface of the cell structure, A method for manufacturing an electrode assembly, characterized in that the third winding step further includes a step of winding the cover part of the separator sheet so that the second bottom cover part of the cover part of the separator sheet connected to the third side cover part of the separator sheet comes into contact with the first bottom cover part of the separator sheet.

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