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EP-4307433-B1 - METHOD AND SYSTEM FOR MANUFACTURING BATTERY CELL

EP4307433B1EP 4307433 B1EP4307433 B1EP 4307433B1EP-4307433-B1

Inventors

  • PARK, WI DAE
  • JUNG, Tae Kwang
  • KIM, SEOL HEE
  • KIM, MIN SU
  • PARK, DONG WOOK
  • SEO, DONG MIN

Dates

Publication Date
20260506
Application Date
20220331

Claims (9)

  1. A method for manufacturing a battery cell (1), the method comprising: a sealing process (S1) of forming a sealing part (30) on a battery cell (1), in which an electrode assembly (10) is accommodated in a pouch (20); a transfer process (S2) of transferring the battery cell (1) to locate the sealing part (30) between a first confocal-sensor (311) and a second confocal-sensor (312), which are disposed to face each other; and a measurement process (S4, S4') of measuring a thickness (t1, t2, t3) of the sealing part (30) through the first confocal-sensor (311) and the second confocal-sensor (312); and a fixing process (S3) performed between the transfer process (S2) and the measuring process (S4, S4'), wherein the sealing part (30) is fixed in an unfolded state using a fixing member (330, 331, 332), wherein the fixing member (330, 331, 332) comprises a first fixing member (331) that supports one surface of the sealing part (30) in the unfolded state, and a second fixing member (332) that faces the first fixing member (331) and supports the other surface of the sealing part (30) in the unfolded state, wherein an opening (330a) configured to reveal at least a portion of the sealing part (30) with respect to the first confocal-sensor (311) and the second confocal-sensor (312) is formed in the fixing member (330, 331, 332), and wherein each of the first confocal-sensor (311) and the second confocal-sensor (312) is provided in a pair to measure thicknesses of a pair of sealing parts (30) disposed at sides opposite to each other with the electrode assembly (10) therebetween.
  2. The method of claim 1, wherein, in the measurement process (S4, S4'), the first confocal-sensor (311) and the second confocal-sensor (312) continuously or discontinuously measure the thickness (t1, t2, t3) of the sealing part (30) while moving in a longitudinal direction of the sealing part (30).
  3. The method of claim 1, wherein, in the measurement process (S4, S4'), the first confocal-sensor (311) and the second confocal-sensor (312) sequentially measure thicknesses (t1, t2, t3) at a plurality of points (P1, P2, P3) different from each other while moving in a longitudinal direction of the sealing part (30).
  4. The method of claim 3, wherein at least one of the plurality of points (P1, P2, P3) is a position corresponding to an electrode lead (12, 13).
  5. A system for manufacturing a battery cell (1), the system comprising: a sealing unit (100) configured to form a sealing part (30) on a battery cell (1), in which an electrode assembly (10) is accommodated in a pouch (20); a measurement unit (300) comprising a first confocal-sensor (311) and a second confocal-sensor (312), which are disposed to face each other; a transfer unit (200) configured to transfer the battery cell (1) so that the sealing part (30) is disposed between the first confocal-sensor (311) and the second confocal-sensor (312); and wherein the measurement unit (300) further comprises a fixing member (330, 331, 332) configured to fix the sealing part (30) in an unfolded state; and a controller (600) configured to calculate a thickness (t1, t2, t3) of the sealing part (30) based on a distance (D1) from the first confocal-sensor (311) to one surface of the sealing part (30) and a distance (D2) from the second confocal-sensor (312) to the other surface of the sealing part (30), wherein the fixing member (330, 331, 332) comprises a first fixing member (331) that supports one surface of the sealing part (30) in the unfolded state, and a second fixing member (332) that faces the first fixing member (331) and supports the other surface of the sealing part (30) in the unfolded state, wherein an opening (330a) configured to reveal at least a portion of the sealing part (30) with respect to the first confocal-sensor (311) and the second confocal-sensor (312) is formed in the fixing member (330, 331, 332), and wherein each of the first confocal-sensor (311) and the second confocal-sensor (312) is provided in a pair to measure thicknesses of a pair of sealing parts (30) disposed at sides opposite to each other with the electrode assembly (10) therebetween.
  6. The system of claim 5, further comprising a discharge unit (400) configured to discharge the battery cell (1), in which the thickness (t1, t2, t3) of the sealing part (30) is completely measured, to a subsequent process line, wherein the subsequent process line comprises a process of injecting an electrolyte into the battery cell (1).
  7. The system of claim 5, wherein the measurement unit (300) further comprises a moving device (320) configured to move the first confocal-sensor (311) and the second confocal-sensor (312) in parallel to a longitudinal direction of the sealing part (30), and the first confocal-sensor (311) and the second confocal-sensor move by the moving device (320) to continuously or discontinuously measure the thickness (t1, t2, t3) of the sealing part (30) in the longitudinal direction of the sealing part (30).
  8. The system of claim 5, wherein the measurement unit (300) further comprises a moving device (320) configured to move the first confocal-sensor (311) and the second confocal-sensor (312) in parallel to a longitudinal direction of the sealing part (30), and the first confocal-sensor (311) and the second confocal-sensor move by the moving device (320) to sequentially measure thicknesses (t1, t2, t3) at a plurality of points (P1, P2, P3) different from each other in the longitudinal direction of the sealing part (30).
  9. The system of claim 5, further comprising a storage (700) configured to store thickness data calculated in the controller (600), wherein the controller (600) is configured to: derive a critical range based on a plurality of pieces of thickness data stored in the storage (700) for a sample group constituted by a plurality of secondary batteries (1); and determine that one secondary battery (1) is defective when the thickness (t1, t2, t3) of the sealing part (30) is out of the critical range in the one secondary battery (1).

Description

TECHNICAL FIELD TECHNICAL FIELD The present invention relates to a method and system for manufacturing a battery cell, and more particularly, to a method and system for manufacturing a pouch-type battery cell. BACKGROUND ART In general, secondary batteries include nickelcadmium batteries, nickel-hydrogen batteries, lithium ion batteries, and lithium ion polymer batteries. Such a secondary battery is being applied to be used in small-sized products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, portable game devices, power tools, E-bikes, and the like as well as large-sized products requiring high power such as electric vehicles and hybrid vehicles, power storage devices for storing surplus power or renewable energy, and backup power storage devices. In general, in order to manufacture the secondary battery, first, electrode active material slurry is applied to a positive electrode collector and a negative electrode collector to manufacture a positive electrode and a negative electrode. Then, the electrodes are stacked on both sides of a separator to form an electrode assembly. Also, the electrode assembly is accommodated in a battery case, and then the battery case is sealed after an electrolyte is injected therein. The secondary battery may be classified into a pouch-type battery cell and a can-type battery cell according to a material of the case accommodating the electrode assembly. Particularly, in the pouch-type battery cell (hereinafter, referred to as a battery cell), an electrode assembly and an electrolyte are accommodated in a pouch. In addition, it is common to inspect a thickness of a sealing part of the battery cell as one of the quality evaluations of the battery cell. The sealing part means a portion in which portions facing each other in the pouch are bonded to each other by welding. However, in the related art, an operator manually inspected the thickness of the sealing part using a micrometer or the like. Thus, there is a problem that the total inspection is impossible, and accuracy and reliability in thickness measurement are deteriorated. KR 2018 0 049 512 A describes a battery cell manufacturing system capable of automatically inspecting the thickness of a sealing portion of a manufactured battery cell. KR 102 146 945 B1 describes an inspection facility for inspecting a secondary battery cell, particularly a pouch-shaped secondary battery cell. KR 2021 0 026 296 A describes a thickness measuring apparatus for measuring the thickness of thin sheets such as positive or negative electrode sheets of secondary batteries. A first thickness sensor and a second thickness sensor are fixedly installed oppositely to the sheet conveyed by a plurality of rollers therebetween. The first thickness sensor and the second thickness sensor may be any one of an ultrasonic sensor, a laser sensor, and a confocal sensor. A sensor support part including the first thickness sensor and a second thickness sensor is movable perpendicular to the transfer direction of the sheet. The sensor support part has a through opening formed so that the sheet passes. DISCLOSURE OF THE INVENTION TECHNICAL PROBLEM An object achieved by the present invention is to provide a method and system for manufacturing a battery cell, which are capable of performing total inspection by automatically inspecting a thickness of a sealing part of the battery cell. Another object achieved by the present invention is to provide a method and system for manufacturing a battery cell, in which accuracy and reliability of measuring a thickness of a sealing part of the battery cell are improved. TECHNICAL SOLUTION A method for manufacturing a battery cell according to an embodiment of the present invention includes: a sealing process of forming a sealing part on a battery cell, in which an electrode assembly is accommodated in a pouch; a transfer process of transferring the battery cell to locate the sealing part between a first confocal-sensor and a second confocal-sensor, which are disposed to face each other; and a measurement process of measuring a thickness of the sealing part through the first confocal-sensor and the second confocal-sensor. The method further includes a fixing process of fixing the sealing part in an unfolded state using a fixing member, which is performed between the transfer process and the measurement process. The fixing member comprises a first fixing member that supports one surface of the sealing part in the unfolded state, and a second fixing member that faces the first fixing member and supports the other surface of the sealing part in the unfolded state. An opening configured to reveal at least a portion of the sealing part with respect to the first confocal-sensor and the second confocal-sensor is formed in the fixing member. Each of the first confocal-sensor and the second confocal-sensor is provided in a pair to measure thicknesses of a pair of sealing parts disposed at sides opposite to each other with