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JP-7856104-B2 - Pouch-type batteries and sealing devices for pouch-type batteries

JP7856104B2JP 7856104 B2JP7856104 B2JP 7856104B2JP-7856104-B2

Inventors

  • ナ、セウン ホ
  • チョイ、クワン ヒー
  • ハ、ドン キュン
  • リー、ヨーン ベオム
  • キム、ド ウー
  • リー、ヒェ ジ

Assignees

  • エルジー エナジー ソリューション リミテッド

Dates

Publication Date
20260511
Application Date
20221117
Priority Date
20211130

Claims (12)

  1. In a sealing device for pouch-type batteries, An upper sealing block having two upper sealing grooves formed, including a first upper step that forms the bottom surface and a second upper step formed between the first upper step and the surface, A lower sealing block having two lower sealing grooves formed, including a first lower step that forms the bottom surface and a second lower step formed between the first lower step and the surface, The upper sealing block is in contact with the first surface of the electrode lead sealing portion of the pouch-type battery, and the lower sealing block is in contact with the second surface of the electrode lead sealing portion of the pouch-type battery at a position facing the upper sealing block. The following condition 1 is met, [Condition 1] In the above condition 1, A1 indicates the height of the first upper step in the upper sealing block. A2 is a sealing device for pouch-type batteries, indicating the height of the first lower step in the lower sealing block.
  2. The height of the first upper step in the upper sealing block is in the range of 200 to 280 μm. The sealing device for a pouch-type battery according to claim 1, wherein the height of the first lower step in the lower sealing block is in the range of 220 to 320 μm.
  3. The sealing device for a pouch-type battery according to claim 1, wherein the difference between the height of the second upper step and the height of the second lower step is 10 μm or less.
  4. The sealing device for a pouch-type battery according to claim 3, wherein the height of the second upper step and the height of the second lower step are each in the range of 40 to 100 μm.
  5. The upper sealing block and the lower sealing block are structured to pressurize and heat the electrode lead sealing portion of the pouch-type battery on both sides. A sealing device for pouch-type batteries according to any one of claims 1 to 4, wherein the heating temperature is in the range of 110 to 200°C.
  6. Electrode assembly and An electrode lead extending from the electrode tab of the electrode assembly, It includes an upper pouch and a lower pouch for housing and sealing the electrode assembly, Based on the electrode lead sealing portion, which has a structure in which the upper pouch and the lower pouch enclose the electrode lead of the electrode assembly on both sides so that the electrode lead is exposed, the following condition 2 is met: [Condition 2] 1≦T2-T1≦25 (μm) In the above condition 2, T1 indicates the average thickness of the upper pouch formed on the first surface of the electrode lead. T2 represents the average thickness of the lower pouch formed on the second surface of the electrode lead, in a pouch-type battery.
  7. Using the electrode lead sealing portion as a reference, The pouch-type battery according to claim 6, wherein the average thickness of the upper pouch formed on the first surface of the electrode lead is in the range of 80 to 90 μm, and the average thickness of the lower pouch formed on the second surface of the electrode lead is in the range of 91 to 105 μm.
  8. The upper pouch and the lower pouch each include a first resin layer located on the inner surface, a metal layer, and a second resin layer located on the outer surface, Using the electrode lead sealing portion as a reference, The thickness ratio of the first resin layer of the upper pouch is in the range of 10 to 18% based on the thickness of the upper pouch. The pouch-type battery according to claim 6, wherein the thickness ratio of the first resin layer of the lower pouch is in the range of 20 to 30% based on the thickness of the lower pouch.
  9. Using the electrode lead sealing portion as a reference, The thickness of the first resin layer of the upper pouch is in the range of 8 to 17 μm on average. The pouch-type battery according to claim 8, wherein the thickness of the first resin layer of the lower pouch is in the range of 20 to 30 μm on average.
  10. The pouch-type battery includes an unsealed region corresponding to the position in which the electrode assembly is housed, between the upper pouch and the lower pouch, where the seal is not maintained. The pouch-type battery according to claim 8, wherein in the unsealed region, the thickness of the first resin layer of the upper pouch and the lower pouch is in the range of 50 to 100 μm on average.
  11. The upper pouch and the lower pouch each contain a polypropylene resin which forms the first resin layer. It contains aluminum or an aluminum alloy that forms a metallic layer. The pouch-type battery according to claim 6, comprising a PET resin that forms the second resin layer.
  12. The electrode assembly is a stacked electrode assembly, as described in any one of claims 6 to 11, for the pouch-type battery.

Description

This application claims priority under Korean Patent Application No. 10-2021-0167905 dated November 30, 2021, and all content disclosed in the said Korean Patent Application is incorporated herein by reference. This invention relates to a pouch-type battery and a sealing device for the pouch-type battery, and prevents the phenomenon in which the thickness of the lower pouch decreases during the heat-sealing process, thereby reducing safety. The increasing technological development and demand for mobile devices, along with the rapidly growing demand for rechargeable batteries as an alternative energy source to fossil fuels, have led to extensive research into rechargeable batteries capable of meeting diverse needs. From the perspective of battery case shape, secondary batteries can be broadly classified into cylindrical and rectangular batteries, where the electrode assemblies are housed in cylindrical or rectangular metal cans, and pouch-type batteries, where the electrode assemblies are housed in a pouch-type case made of aluminum laminate sheet. In terms of materials, there is high demand for lithium-ion batteries and lithium-ion polymer batteries, which excel in terms of high energy density, discharge voltage, and output stability. Among these, pouch-type batteries are in high demand due to their advantages in terms of shape: their thin profile, ease of stacking, and the ability to partially deform their shape. Pouch-type batteries consist of a pouch-type laminate sheet containing the electrode assembly and electrolyte, and the resin layer of the laminate sheet is characterized by its ability to be heat-fused. In pouch-type batteries, heat and pressure are applied to laminate sheets that are layered vertically around the battery case to seal the electrode assembly and prevent electrolyte leakage, thus preventing the electrode assembly from being exposed to the outside. Electrode leads protrude from the outside of the pouch-type battery case, and lead films are attached to the surface of the electrode leads. These insulating resin lead films are heat-sealed together with the laminate sheets (i.e., the pouch), providing a more robust seal around the electrode leads. However, when heat-sealing pouches, the pair of pouches enclosing the electrode assembly and electrode leads often exhibit differences in thickness after heat sealing. While a pair of upper and lower sealing blocks are used to apply heat and pressure to seal the electrode leads and pouches, the sealing process involves raising the lower sealing block to support the lower pouch and electrode leads, followed by lowering the upper sealing block to apply heat and pressure. This results in more heat being supplied to the lower pouch and electrode leads, making the resin layer of the lower pouch more likely to become thinner than that of the upper pouch. The relatively thin lower pouch is more vulnerable to internal or external pressure. For example, when pressure below the specified endurance limit acts on a pouch-type battery, the upper pouch may withstand the pressure while the lower pouch ruptures, or the internal pressure from gas generated within the pouch may stretch and break the resin layer of the lower pouch, causing the seal to open. This is a schematic diagram illustrating the process of sealing a pouch-type battery using a sealing device 10 (hereinafter abbreviated as "sealing device") according to one embodiment of the present invention.This is a schematic cross-sectional view illustrating a sealing device for a pouch-type battery according to one embodiment of the present invention.This is a schematic diagram illustrating the process of sealing the electrode lead formation portion of a pouch-type battery using a pouch-type battery sealing device according to one embodiment of the present invention.This is a schematic diagram illustrating a pouch-type battery 500 that has been sealed using the pouch-type battery sealing device according to the present invention.This is a partially enlarged view of the A-A' cross-section of the pouch-type battery 500 shown in Figure 4. The present invention can be modified in various ways and may have many different embodiments; therefore, specific embodiments will be described in detail below. However, this is not intended to limit the present invention to any particular embodiment, but should be understood to include all modifications, equivalents, or substitutions that fall within the spirit and technical scope of the present invention. In this invention, terms such as "includes" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, without pre-existing exclusion of the presence or possibility of adding one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Furthermore, in this invention, when a part such as a layer, film, region, or plate is descri