KR-102963547-B1 - CELL POUCH PACKAGING STRUCTURE AND METHOD OF FORMING THE SAME

KR102963547B1KR 102963547 B1KR102963547 B1KR 102963547B1KR-102963547-B1

Abstract

A cell pouch packaging structure according to the present invention comprises a cell pouch wound onto a cylindrical tube and an inner packaging material surrounding the cell pouch in at least one layer, wherein the cell pouch comprises an inner layer, a metal layer, and an outer layer. Additionally, a method for forming a cell pouch packaging structure according to the present invention may be performed using components of the cell pouch packaging structure.

Inventors

송녹정
한희식
김희훈
이두희
신성철
송문규
김유한

Assignees

율촌화학 주식회사

Dates

Publication Date: 20260513
Application Date: 20240430

Claims (20)

A cell pouch packaging structure comprising a cell pouch located at the outermost edge of a secondary battery and used as a material for an outer body surrounding the secondary battery, wherein A cell pouch comprising an inner layer, a metal layer, and an outer layer, wound onto a cylindrical tube; and It includes an inner packaging material that surrounds the cell pouch with at least one layer, and The above inner packaging material has a water vapor transmission rate (WVTR) of 0.1 g/ m² *day to 1.0 g/ m² *day, and The cell pouch above is a cell pouch packaging structure having a residual moisture content of 300 ppm to 1300 ppm as measured as follows: [Method for Measuring Residual Moisture Content] To measure the residual moisture content of the cell pouch, the cell pouch is cut into pieces measuring 60 mm in width and 40 mm in length, and then divided into four equal parts along the horizontal direction to create samples for measuring the residual moisture content. Accordingly, individual samples are 15 mm in width and 40 mm in length. The prepared samples for measuring the residual moisture content are placed in a moisture content measurement vial and sealed. The moisture content of the sealed samples is measured using a moisture meter under conditions of a temperature of 150 degrees and a gas flow of 50 ml/min.
In Article 1, The outer layer of the cell pouch above comprises nylon, and The above nylon has a moisture content of 4,000 ppm to 10,000 ppm or a moisture content of 300 µg to 900 µg; and/or A cell pouch packaging structure in which the ratio of the moisture content of the nylon to the moisture content of the cell pouch is 70% to 87% by weight.
In Article 2, The inner layer of the cell pouch above comprises polypropylene, and The metal layer of the cell pouch above comprises aluminum (Al), and The outer layer of the cell pouch comprises polyethylene terephthalate (PET) and nylon, and A cell pouch packaging structure having the above polyethylene terephthalate having a thickness of 12 to 25 μm and the above nylon having a thickness of 3 to 30 μm.
In Article 1, The above inner packaging material is a cell pouch packaging structure having a water vapor transmission rate (WVTR) of 0.28 g/ m² *day to 0.59 g/ m² *day.
In Article 1, The above cylindrical tube is a cell pouch packaging structure comprising polypropylene (PP).
In Article 1, The above inner packaging material is, A cell pouch packaging structure that surrounds the cell pouch on the outer surface of the cylindrical tube, is inserted from individual sides of the cylindrical tube at both sides toward the opening of the cylindrical tube to fill the opening of the cylindrical tube, and attaches the end of the inner packaging material to the inner end of the inner packaging material through a tape at the end of the inner packaging material.
In Article 1, The above inner packaging material comprises vacuum metallized cast polypropylene (VMCPP) or an aluminum bag (Al bag), and The above aluminum bag is a cell pouch packaging structure comprising sequentially laminated nylon, aluminum, and linear low density polyethylene (LLDPE).
In Article 1, It further includes an outer packaging material surrounding the inner packaging material, and The above outer packaging material is, A cell pouch packaging structure made of sheet-shaped styrofoam, wound onto the inner packaging material, and having the end of the outer packaging material attached to the inner end of the outer packaging material through tape at the end of the outer packaging material.
In Article 1, It further includes a decorative packaging material located in the above-mentioned cylindrical tube and in at least one of the above-mentioned inner packaging materials, The above decorative packaging material is, A desiccant located inside the above-mentioned cylindrical tube, and A tube fitting cap that presses the inner packaging material from individual sides of the cylindrical tube toward the inlet of the cylindrical tube at both sides of the cylindrical tube, and A paper disc positioned between the inner packaging material and the tube fitting cap on both sides of the above-mentioned cylindrical tube and penetrating the tube fitting cap, and A cell pouch packaging structure comprising at least one of a vacuum vinyl bag that surrounds the inner packaging material with a vacuum atmosphere.
In Article 9, The above moisture absorbent is, A cell pouch packaging structure comprising a nonwoven fabric that accommodates a plurality of silica gel granules or calcium chloride granules.
In Article 9, The above tube fitting cap is, Includes plastic, A cell pouch packaging structure comprising a free node cap exposed from the cylindrical tube on the inner packaging material and a restrained node cap inserted into the cylindrical tube on the inner packaging material.
In Article 11, The above free node cap and the above constrained node cap are, Communicate with each other, The above free node cap is, Having an opening that exposes the internal space of the restrained node cap to the outside of the free node cap, the opening can be kept open, or a blocking tape can be placed over the opening to keep the opening closed, The internal space of the above-mentioned restraint node cap is not exposed to the outside of the above-mentioned free node cap, or A cell pouch packaging structure formed in a one-touch cap manner having an opening/closing lid in the central area of the free node cap, wherein when the opening/closing lid is opened, the internal space of the restraining node cap is exposed to the outside of the tube fitting cap.
In Article 9, The above paper disc is, When the above cylindrical tube is positioned horizontally with respect to the ground in the packaging box, A cell pouch packaging structure that separates the inner packaging material from the packaging box at both sides of the above-mentioned cylindrical tube.
In Article 9, The above vacuum vinyl bag is, A cell pouch packaging structure that connects the internal space of the vacuum vinyl bag to an air intake motor part, thereby lowering the pressure of the internal space of the vacuum vinyl bag from atmospheric pressure to vacuum through the air intake motor part to enclose the inner packaging material.
A method for forming a cell pouch packaging structure comprising a cell pouch located at the outermost part of a secondary battery and used as a material for an outer body surrounding the secondary battery, wherein Prepare a cell pouch comprising an inner layer, a metal layer, and an outer layer, which is wound onto a cylindrical tube, and The cell pouch above is wrapped with at least one layer of inner packaging material, and The above inner packaging material has a water vapor transmission rate (WVTR) of 0.1 g/ m² *day to 1.0 g/ m² *day, and A method for forming a cell pouch packaging structure, wherein the cell pouch above has a residual moisture content of 300 ppm to 1300 ppm as measured as follows: [Method for Measuring Residual Moisture Content] To measure the residual moisture content of the cell pouch, the cell pouch is cut into pieces measuring 60 mm in width and 40 mm in length, and then divided into four equal parts along the horizontal direction to create samples for measuring the residual moisture content. Accordingly, individual samples are 15 mm in width and 40 mm in length. The prepared samples for measuring the residual moisture content are placed in a moisture content measurement vial and sealed. The moisture content of the sealed samples is measured using a moisture meter under conditions of a temperature of 150 degrees and a gas flow of 50 ml/min.
In Article 15, Wrapping with the above inner packaging material is, Using the above inner packaging material, the cell pouch is surrounded on the outer surface of the cylindrical tube, and Using the above inner packaging material, it is inserted from both sides of the cylindrical tube from individual sides of the cylindrical tube toward the entrance of the cylindrical tube to fill the entrance of the cylindrical tube, and A method for forming a cell pouch packaging structure, comprising attaching the end of the inner packaging material to the inner end of the inner packaging material through a tape at the end of the inner packaging material.
In Article 15, The above inner packaging material comprises vacuum metallized cast polypropylene (VMCPP) or an aluminum bag (Al bag), and A method for forming a cell pouch packaging structure comprising sequentially laminated nylon, aluminum, and linear low density polyethylene (LLDPE), wherein the above aluminum bag comprises
In Article 15, It further includes surrounding the inner packaging material with an outer packaging material, The above outer packaging material, When made of sheet-shaped styrofoam, Wrapping with the above outer packaging material is, Using the above outer packaging material, it is wound onto the above inner packaging material, and A method for forming a cell pouch packaging structure, comprising attaching the end of the outer packaging material to the inner end of the outer packaging material through tape at the end of the outer packaging material.
In Article 15, A first decorative packaging material is placed in the above cylindrical tube, and It further includes positioning a second decorative packaging material on at least one of the above-mentioned cylindrical tube and the above-mentioned inner packaging material, and The first decorative packaging material is, It is a moisture absorbent located inside the above-mentioned cylindrical tube, and The second decorative packaging material is, A tube fitting cap that presses the inner packaging material from the individual sides of the cylindrical tube toward the entrance of the cylindrical tube on both sides of the cylindrical tube, A paper disc positioned between the inner packaging material and the tube fitting cap on both sides of the above cylindrical tube and penetrating the tube fitting cap, A method for forming a cell pouch packaging structure comprising at least one of a vacuum vinyl bag that surrounds the inner packaging material with a vacuum atmosphere.
In Article 15, It further includes positioning a second decorative packaging material on at least one of the above-mentioned cylindrical tube and the above-mentioned inner packaging material, and The second decorative packaging material is, A tube fitting cap that presses the inner packaging material from individual sides of the cylindrical tube toward the inlet of the cylindrical tube at both sides of the cylindrical tube, and A method for forming a cell pouch packaging structure comprising a paper disc positioned between the inner packaging material and the tube fitting cap on both sides of the above-mentioned cylindrical tube and penetrating the tube fitting cap.

Description

Cell Pouch Packaging Structure and Method of Forming the Same The present invention relates to a cell pouch packaging structure comprising a cell pouch located at the outermost part of a secondary cell and used as a material for an outer body surrounding the secondary cell, and a method for forming the same. Generally, lithium-ion batteries have the advantage of having a high energy density among batteries that convert chemical energy into electrical energy, no decrease in capacity even after repeated charging and discharging, and high operating voltage, which allows for the miniaturization and weight reduction of the devices used. In addition, the lithium-ion batteries have high thermal stability, so they are used not only as core components responsible for powering everything from IT devices for mobile communication to electric vehicles, but also as power sources for portable electronic devices used in the daily lives of modern people. Here, the lithium secondary battery consists of an anode, a cathode, an electrolyte, a separator, and an outer body that packages them. The outer body is often made into a cell pouch, which has a degree of freedom of shape rather than a cylindrical or rectangular shape formed by press processing. According to the prior art, the cell pouch (50) of FIG. 1 is wound onto a cylindrical tube (10) before being processed into an outer body, and is surrounded by an inner packaging material (see Comparative Examples 1 & 2 of FIG. 8) to form a cell pouch packaging structure (60) together with the inner packaging material. Specifically, the cell pouch (50) has an inner layer (20) and an outer layer (40), and a metal layer (30) between the inner layer (20) and the outer layer (40). The inner layer (20) and the outer layer (40) are resin layers. The inner packaging material is low density polyethylene (LDPE) or vacuum metallized cast polypropylene (VMCPP). The cell pouch (50) is unwound from the cylindrical tube (10) while separated from the inner packaging material, repeatedly cut into fragment cell pouches, and then the fragment cell pouches are molded as shown in FIG. 2 to form an outer body (70). The outer body (70) has a lower outer body (56) and an upper outer body (58). Structurally, the lower outer body (56) and the upper outer body (58) are composed of a fragment inner layer (25), a fragment metal layer (35), and a fragment outer layer (45). The lower outer body (56) and the upper outer body (58) each have a receiving portion (52) and a sealing portion (54) when viewed from the outside. The receiving portion (52) of the lower outer body (56) and the receiving portion (52) of the upper outer body (58) accommodate electrodes of a secondary battery (not shown in the drawing). The sealing portion (54) of the lower outer body (56) and the sealing portion (54) of the upper outer body (58) are heat-fused through the segment inner layer (25) of the lower outer body (56) and the segment inner layer (25) of the upper outer body (58) by applying heat and pressure from the outside. Here, during the thermal fusion of the segment inner layer (25) of the lower outer body (56) and the segment inner layer (25) of the upper outer body (58), the sealing portion (54) of the lower or upper outer body (56 or 58) is sometimes thermally deformed while generating bubbles due to residual moisture in the segment outer layer (45). This thermal deformation causes the sealing portion (54) of the lower or upper outer body (56 or 58) to expand up to 400% of the initial thickness before thermal fusion, based on the residual moisture in the segment outer layer (45). Accordingly, the above thermal deformation causes a decrease in peel strength in the sealing portion (54) of the lower and upper outer bodies (56, 58) and causes lifting in high temperature and high humidity environments, resulting in electrolyte leakage from the secondary battery and explosion of the secondary battery during the manufacture of the secondary battery. To verify the relationship between residual moisture in the cell pouch (50) and thermal deformation, a cell pouch packaging structure (60; corresponding to Comparative Example 1 or Comparative Example 2 in the table of FIG. 8) was additionally prepared. The cell pouch packaging structure (60) was placed in a constant temperature and humidity chamber and exposed to a temperature of 60 degrees and a relative humidity (RH) of 90% for a predetermined period of time. After removing the cell pouch packaging structure (60) from the above-mentioned constant temperature and humidity chamber, the cell pouch (50) was separated from the inner packaging material in the cell pouch packaging structure (60). The cell pouch (50) was repeatedly cut to make samples for measuring residual moisture content (refer to the sample preparation process in the detailed description of FIGS. 5 to 7) and samples for checking thermal deformation (refer to the sample preparation process in the detailed description of FI