# US 2026/0066471 A1 · Electrode assembly and secondary battery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0066471 A1 - Document ID: US20260066471A1 - Status: Published application - Kind: A1 - Application number: 19/311,601 - Filed: 2025-08-27 - Published: 2026-03-05 - Earliest claimed: 2024-08-28 - Assignees: Samsung SDI Co., Ltd. - Applicants: Samsung SDI Co., Ltd. - Inventors: Min Hyung GUEN - Web page: https://patentgrep.com/patent/US20260066471A1 ## CPC - H01M 50/466: U-shaped, bag-shaped or folded - H01M 10/0459: {Cells or batteries with folded separator between plate-like electrodes} - H01M 10/0583: of accumulators with folded construction elements except wound ones, i.e. folded positive or negative electrodes or separators, e.g. with "Z"-shaped electrodes or separators - H01M 50/531: Electrode connections inside a battery casing - H01M 50/609: Arrangements or processes for filling with liquid, e.g. electrolytes - H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries - Y02E 60/10: Energy storage using batteries - Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract The present disclosure relates to an electrode assembly, and a technical problem to be addressed includes providing an electrode assembly with improved impregnation. The present disclosure describes an electrode assembly that includes a first electrode and a second electrode, and a separator between the first electrode and the second electrode. The electrodes and the separator are stacked in one direction, and the separator includes one or more holes formed in the stacking direction of the separator. ## Claims ### Claim 1 An electrode assembly comprising: a first electrode and a second electrode; and a separator between the first electrode and the second electrode, wherein the electrodes and the separator are stacked in one direction, and the separator includes one or more holes formed in the stacking direction of the separator. ### Claim 2 (depends on 1) The electrode assembly of claim 1, wherein: the separator is folded in a substantially Z shape along a plurality of folding portions spaced apart from each other, and the first electrode and the second electrode are alternately located in the folded separator. ### Claim 3 (depends on 2) The electrode assembly of claim 2, further comprising a plurality of unit structures stacked in the stacking direction, wherein at least one of the unit structures includes a separator including two folding portions, one first electrode with one side facing the folding portion, and one second electrode with the other side facing the folding portion. ### Claim 4 (depends on 3) The electrode assembly of claim 3, wherein the one or more holes are formed in at least one of the plurality of unit structures along the stacking direction. ### Claim 5 (depends on 4) The electrode assembly of claim 4, wherein the one or more holes are formed so that at least a portion of the one or more holes overlap each other in the stacking direction. ### Claim 6 (depends on 4) The electrode assembly of claim 4, wherein the one or more holes are offset in the stacking direction. ### Claim 7 (depends on 3) The electrode assembly of claim 3, wherein the same number of the one or more holes are formed in each of the plurality of unit structures. ### Claim 8 (depends on 3) The electrode assembly of claim 3, wherein different numbers of the one or more holes are formed in at least some of the plurality of unit structures. ### Claim 9 (depends on 2) The electrode assembly of claim 2, wherein the one or more holes are formed in the folding portion. ### Claim 10 (depends on 2) The electrode assembly of claim 2, wherein the one or more holes are formed adjacent to the folding portion. ### Claim 11 (depends on 2) The electrode assembly of claim 2, wherein the one or more holes are formed on one of one side and both sides of the electrode assembly. ### Claim 12 A secondary battery comprising: a case; and an electrode assembly included in the case, wherein the electrode assembly includes a first electrode and a second electrode, and a separator between the first electrode and the second electrode, the electrodes and the separator are stacked in one direction, and the separator includes one or more holes formed in the stacking direction of the separator. ### Claim 13 (depends on 12) The secondary battery of claim 12, wherein the separator is folded substantially in a Z shape along a plurality of folding portions spaced apart from each other, and the first electrode and the second electrode are alternately located in the folded separator. ### Claim 14 (depends on 13) The secondary battery of claim 13, wherein: the electrode assembly includes a plurality of unit structures stacked in the stacking direction, and at least one of plurality of the unit structures includes a separator including two folding portions, one first electrode with one side facing the folding portion, and one second electrode with the other side facing the folding portion. ### Claim 15 (depends on 14) The secondary battery of claim 14, wherein the one or more holes are formed in at least one of the plurality of unit structures in the stacking direction. ### Claim 16 (depends on 15) The secondary battery of claim 15, wherein the one or more holes are formed so that at least a portion of the one or more holes overlap each other in the stacking direction. ### Claim 17 (depends on 15) The secondary battery of claim 15, wherein the one or more holes are offset in the stacking direction. ### Claim 18 (depends on 14) The secondary battery of claim 14, wherein the same number of the one or more holes are formed in each of the plurality of unit structures. ### Claim 19 (depends on 14) The secondary battery of claim 14, wherein different numbers of the one or more holes are formed in at least some of the plurality of unit structures. ### Claim 20 (depends on 12) The secondary battery of claim 12, further comprising a tab electrically connected to the electrodes and extending to the outside of the separator, wherein the hole is formed on a side that is different from the side from which the tab extends.