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KR-102963497-B1 - Easy to check swollen cell case and battery cell comprising the same

KR102963497B1KR 102963497 B1KR102963497 B1KR 102963497B1KR-102963497-B1

Abstract

The present invention relates to a secondary battery in which expansion of a cell case is easily confirmed and a method for checking whether expansion has occurred. More specifically, the invention relates to a secondary battery in which an electrode assembly (200) is housed inside a case (100), wherein an expansion confirmation means (300) is provided on the outer surface of the case (100), and a secondary battery in which expansion of a cell case is easily confirmed and a method for checking whether expansion has occurred.

Inventors

  • 최진형

Assignees

  • 주식회사 엘지에너지솔루션

Dates

Publication Date
20260511
Application Date
20201014

Claims (10)

  1. In a secondary battery in which an electrode assembly (200) is housed inside a case (100), An expansion confirmation means (300) is provided on the outer surface of the above case (100), and The above expansion confirmation means (300) is characterized by having a shape in which the first pattern (310) and the second pattern (320) intersect.
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  4. In paragraph 1, A secondary battery characterized in that the first pattern (310) and the second pattern (320) are made of solid lines.
  5. In paragraph 1, A secondary battery characterized in that the first pattern (310) and the second pattern (320) are composed of dashed lines.
  6. In paragraph 1, The above expansion confirmation means (300) is characterized by including a substrate (330) fixed to the outer surface of the case (100) with the first pattern (310) and the second pattern (320) formed on the outer surface.
  7. In paragraph 6, A secondary battery characterized in that an adhesive or adhesive is applied to one side surface of the substrate (330) facing the outer surface of the case (100).
  8. In paragraph 6, A secondary battery characterized in that the substrate (330) facing the outer surface of the above case (100) is made of a laminate sheet in which a resin layer and a metal layer are sequentially laminated.
  9. A battery module comprising a secondary battery as described in any one of paragraphs 1, 4 through 8.
  10. A method for inspecting whether a secondary battery has expanded as described in any one of paragraphs 1, 4 through 8, wherein A method for checking whether a secondary battery has expanded, characterized by determining whether there is deformation of an expansion confirmation means (300) provided on the outer surface of the case (100).

Description

Secondary battery with easy verification of cell case expansion and method for checking expansion {Easy to check swollen cell case and battery cell comprising the same} The present invention relates to a secondary battery and a method for inspecting whether it has expanded, and more specifically, to a secondary battery and a method for inspecting whether it has expanded, in which the expansion of the cell case can be easily confirmed from the deformation of an expansion confirmation means provided on the outer surface of the cell case. With the increasing technological development and demand for mobile devices such as smartphones, laptops, and digital cameras, technologies related to rechargeable secondary batteries are becoming more active. These secondary batteries serve as an alternative energy source to fossil fuels that cause air pollutants and are being applied to electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), and energy storage devices (ESS). Rechargeable batteries can be classified into cylindrical, prismatic, and pouch types based on their shape. Among these, pouch batteries are attracting significant attention due to their ability to be stacked with high integration density, high energy density per unit weight, and ease of shape deformation. A pouch-type battery refers to a battery in which the battery case is made of a laminated sheet, and the electrode assembly is embedded inside the battery case. In general, pouch-type batteries with flexible outer shells may experience expansion due to high temperature phenomena caused by abnormal operating conditions of the battery, such as internal short circuits, overcharging exceeding the allowed current and voltage, exposure to high-temperature environments, or deformation caused by drops or external impacts. In particular, pouch-type lithium-ion batteries experience swelling due to gases generated during the decomposition of the internal electrolyte; this phenomenon is called electrolyte swelling. Since the decomposition of the electrolyte is accelerated at high temperatures, leaving the battery at high temperatures promotes swelling. As the battery temperature rises, the electrolyte decomposes or side reactions occur, generating gases such as carbon dioxide or carbon monoxide, which causes the internal pressure to increase. If this pressure exceeds a certain level, the secondary battery will explode. The risk of explosion caused by such increased internal pressure is considered the biggest disadvantage of lithium-ion batteries. Therefore, safety is an essential consideration in the development of lithium-ion batteries. Battery expansion is a critical measurement factor in terms of both safety and operational performance, and numerous related tests are conducted during the battery testing phase of development. However, there is a problem in that it is difficult to easily verify battery expansion simply by visual inspection. Meanwhile, Patent Document 1 discloses a secondary battery having a structure comprising a sensor member that detects an increase in internal pressure or an increase in temperature of the battery, and a color-changing member that changes color by a signal transmitted from the sensor member, wherein when the sensor member detects a change in pressure or temperature of the battery and transmits an abnormal signal to the color-changing member, the color of the color-changing member changes, thereby allowing an abnormal operation of the battery to be recognized externally. Patent Document 2 discloses a battery in which the pressure rise of the secondary battery is not transmitted to the pressure reducing member, and the state of the pressure reducing member changes when the inversion plate is inverted and the pressure inside the sealed space rises, thereby enabling external recognition of the state, such as a change in color when the internal pressure of the battery case rises and a current cutoff mechanism is activated. Both of these patent documents 1 and 2 disclose a technology for checking changes in internal pressure of a battery cell, but they have the disadvantage that the structure and manufacturing process are complex because additional components, such as sensors, must be provided inside the battery cell. FIG. 1 is an exploded perspective view of a pouch-type secondary battery according to a first embodiment of the present invention. FIG. 2 is an enlarged plan view of the outer surface of the upper case before the secondary battery shown in FIG. 1 expands. FIG. 3 is an enlarged plan view of the outer surface of the upper case after the secondary battery shown in FIG. 1 has expanded. FIG. 4 is a detailed enlarged view of an expansion confirmation means according to a first embodiment of the present invention. FIG. 5 is a detailed enlarged view of an expansion confirmation means according to a second embodiment of the present invention. FIG. 6 is a detailed enlarged view of an