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KR-102963364-B1 - Secondary battery and manufacturing method thereof

KR102963364B1KR 102963364 B1KR102963364 B1KR 102963364B1KR-102963364-B1

Abstract

The present invention is a secondary battery in which an electrode assembly having a positive tab and a negative tab protruding respectively is mounted in a pouch, and a positive lead and a negative lead connected to the positive tab and the negative tab protrude from the pouch, and is formed in a rectangular shape having two short sides of relatively shorter length and two long sides of relatively longer length, wherein the positive lead and the negative lead protrude on the same long side.

Inventors

  • 김성곤
  • 김균섭
  • 권재화
  • 이경민

Assignees

  • 주식회사 엘지에너지솔루션

Dates

Publication Date
20260511
Application Date
20210707

Claims (12)

  1. A secondary battery in which an electrode assembly having a positive tab and a negative tab protruding respectively is mounted in a pouch, and a positive lead and a negative lead connected to the positive tab and the negative tab protrude from the pouch. It is formed in a rectangular shape having two relatively shorter sides and two relatively longer sides, The above positive lead and negative lead protrude in pairs on the same long side, and A concave groove is formed in each of the two long sides, and the paired cathode lead and anode lead protrude within the groove, A secondary battery in which the paired negative lead and positive lead protrude from all of the above grooves.
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  3. In Article 1, A secondary battery characterized by having an inner horizontal side formed within the groove that is parallel to the long side and perpendicular to the short side, and having a positive lead and a negative lead positioned on the inner horizontal side.
  4. In Paragraph 3, A secondary battery characterized in that, in the above-mentioned groove, one side is connected to an internal horizontal side and the other side is connected to a long side, and the internal vertical side has a rounded shape at the end where the connection is made.
  5. In any one of Article 1, Articles 3 to 4, The above electrode assembly is, An anode having a groove formed therein and an anode tab protruding from one side within the groove; A cathode having a groove formed of the same size as the positive electrode, with a negative electrode tab protruding from the other side within the groove; A separator laminated between the cathode and the anode to cover one side of each of the cathode and the anode in the remaining area excluding the anode tab and the cathode tab; A secondary battery characterized in that the positive and negative electrodes are stacked so that their respective grooves are aligned, and the positive tab and negative tab are spaced apart from each other within the grooves.
  6. In Article 5, A secondary battery characterized by having a positive lead attached to the positive tab so as to extend along the longitudinal direction, and a negative lead attached to the negative tab so as to extend along the longitudinal direction.
  7. In Article 6, A secondary battery characterized in that the above pouch has a shape in which a groove is formed corresponding to a groove formed in the electrode assembly, and the remaining points are sealed except for the points where the positive lead and the negative lead protrude outward.
  8. In Article 7, A secondary battery characterized in that the width of the positive lead and the width of the negative lead are formed to be larger than the length of the remaining part excluding the portion where a groove is formed on the long side.
  9. In Article 7, A secondary battery characterized in that the positive lead and the negative lead have a length that does not protrude from the long side.
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Description

Secondary battery and manufacturing method thereof The present invention relates to a secondary battery and a method for manufacturing the same, and more specifically, to a secondary battery and a method for manufacturing the same in which electrode leads (positive lead, negative lead) are arranged on a long side (relatively long side) rather than a short side (relatively short side) to minimize heat generation and increase space utilization of a device in which the secondary battery is mounted. Batteries that store electrical energy can generally be classified into primary and secondary batteries. Primary batteries are disposable, consumable batteries, whereas secondary batteries are rechargeable batteries manufactured using materials capable of repeating oxidation and reduction processes between the current and the material. In other words, when a reduction reaction is performed on the material by the current, the power is charged, and when an oxidation reaction is performed on the material, the power is discharged; this charging and discharging cycle can be performed repeatedly. Among various types of secondary batteries, lithium secondary batteries are generally manufactured by mounting an electrode assembly, in which a cathode, a separator, and an anode are stacked, into a case, and the charging and discharging of the lithium secondary battery proceeds as the process of lithium ions intercalating and deintercalating from the lithium metal oxide of the cathode to the anode is repeated. Meanwhile, as a method for manufacturing the above electrode assembly, a jelly roll type (winding type) is manufactured by stacking a separator between the cathode and the anode and then winding it; a stacking type is manufactured by cutting the cathode and the anode to have the required width and length, and then stacking the cathode, separator, and anode repeatedly; and a stack-and-folding type is manufactured by placing unit cells side by side on a folding separator and then folding from one side. And, these electrode assemblies are mounted in cases such as cans or pouches to be manufactured into secondary batteries. As shown in FIG. 1, which illustrates a perspective view of a conventional pouch-type secondary battery, the double pouch-type secondary battery is configured such that an electrode assembly is mounted inside a pouch (2) and a negative lead (4) and a positive lead (3) protrude from each side along the longitudinal direction. Each of the positive lead (3) and the negative lead (4) is connected to the positive tab and the negative tab of the electrode assembly, respectively, so that current can be conducted. Meanwhile, heat is generated internally as charging and discharging proceeds in secondary batteries. This heat not only adversely affects the lifespan and performance of secondary batteries but can also cause flames or explosions. In particular, there was a problem with heat being concentrated near the positive lead (3) and negative lead (4), which serve as pathways for current flow. Furthermore, in order to increase the capacity of the secondary battery, the thickness or length of the electrode assembly must be gradually increased; however, in this conventional structure, as the capacity increases, there was a problem with heat being further concentrated at both ends where the positive lead (3) and negative lead (4) are located. The ends of the secondary battery have a relatively narrow surface area, so heat dissipation does not occur, and there was a problem in that heat was not efficiently discharged even if a cooling device was added. FIG. 1 is a perspective view of a conventional pouch-type secondary battery. FIG. 2a is a perspective view of a secondary battery according to a first embodiment of the present invention. FIG. 2b is a front view of a secondary battery according to a first embodiment of the present invention. FIG. 3a is a front view of a secondary battery according to a second embodiment of the present invention. FIG. 3b is a front view of a secondary battery according to a third embodiment of the present invention. FIG. 3c is a front view of a secondary battery according to a fourth embodiment of the present invention. FIG. 4 is a drawing showing a line where cutting is performed when processing a positive or negative electrode included in a secondary battery according to the present invention from a plate-shaped raw material. FIG. 5 is a drawing showing the manufacturing of a secondary battery according to the present invention (1. a negative electrode, a separator, and a positive electrode being stacked; 2. a unit cell in which the negative electrode, a separator, and a positive electrode are stacked; 3. a plurality of the unit cells being stacked; 4. a positive lead and a negative lead being welded to each of the positive tab and the negative tab). FIG. 6 is a drawing showing the electrode assembly manufactured as in FIG. 5 being mounted in a pouch. Hereinafter, the present invention