Battery cell and method for manufacturing battery cell

Abstract

The present disclosure relates to a battery cell and a method of manufacturing the battery cell. The battery cell includes: an electrode assembly including a cathode, an anode, and a separator disposed between the cathode and the anode; and an outer material accommodating the electrode assembly therein, in which the outer material includes: a first region including a notch portion provided on an outer surface; and a second region surrounding the first region, in which a tensile strength of the first region is set to be lower than a tensile strength of the second region.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority of Korean Patent Application No. 10-2023-0120339 filed on September 11, 2023 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure generally relates to a battery cell and a method for manufacturing the battery cell. In particular, the present disclosure relates to a battery cell and a method for manufacturing the battery cell having an outer material with variable tensile strength. Background Art

[0004] A secondary battery is a battery that converts electrical energy into chemical energy and stores the chemical energy so that the chemical energy can be reused many times through charging and discharging of the battery. Secondary batteries are widely used in various industries due to their economical and environmentally friendly characteristics. In particular, lithium secondary batteries among secondary batteries are widely used in various industries, including portable devices that require high-density energy.

[0005] The working principle of lithium secondary batteries is electrochemical redox reaction. In other words, the principle is to generate electrical energy through the movement of lithium ions and to be charged in the reverse process. During the charging process, lithium ions move from the cathode to the anode through the electrolyte and are stored in the anode active material through a process called intercalation. During the discharge process, the lithium ions move back to the cathode, releasing electrical energy that can be used to power the device. The separator is set between the cathode and the anode, physically separating the two from each other, but it allows lithium ions to flow through its structure. The charging and discharging process in the secondary battery can be repeated many times. However, as the charging and discharging are repeated many times, an expansion phenomenon in which the internal pressure increases and a large amount of heat is generated may occur. This expansion phenomenon may cause an explosion or fire. Therefore, an improved technology for controlling the internal pressure of secondary batteries is very desirable. Summary of the invention

[0006] An object of the present disclosure is to provide a battery cell having improved internal pressure control and stability and a method of manufacturing the battery cell.

[0007] Another object of the present disclosure is to provide a battery cell having an exterior material with variable tensile strength and a method of manufacturing the battery cell.

[0008] Still another object of the present disclosure is to provide a method of manufacturing a battery cell in which a notch portion and an external material are manufactured as one body to have improved production efficiency.

[0009] The battery cell according to the present disclosure can be widely used in the field of green technology, such as electric vehicles using batteries, battery charging stations, solar power generation and wind power generation. In addition, the battery cell according to the present disclosure can be used in environmentally friendly electric vehicles, hybrid vehicles, etc. to prevent climate change by suppressing air pollution and greenhouse gas emissions.

[0010] In an embodiment, a battery cell according to the present disclosure includes: an electrode assembly including a cathode, an anode and a separator arranged between the cathode and the anode; and an external material, which accommodates the electrode assembly in the external material, wherein the external material includes: a first region including a notch portion arranged on an outer surface; and a second region surrounding the first region; wherein the tensile strength of the first region is set to be lower than the tensile strength of the second region.

[0011] The notched portion may be provided in the form of a groove or an indentation sunken inwardly from the outer surface of the outer material.

[0012] The tensile strength of the first region may be 80% or less of the tensile strength of the second region.

[0013] The elongation rate of the first region may be set to be different from the elongation rate of the second region.

[0014] The elongation of the first region may be greater than the elongation of the second region.

[0015] The elongation of the first region may be 300% or more of the elongation of the second region.

[0016] The exterior material may further include: a body part accommodating the electrode assembly; and a cover part including a cell tab electrically connecting the electrode assembly to the outside and covering the body part, wherein the notch part is provided in the body part.

[0017] The notched portion may be formed integrally with the outer material.

[0018] The notch portion and the vent portion may be positioned to overlap along a recess direction of the at least one surface recess.

[0019] The notch portion may include the same material as the outer material.

[0020] The outer material may further include a vent portion formed by a depression of at least one of the inner surface and the outer surface disposed in a direction opposite to the inner surface, and the notch portion and the vent portion may be positioned to overlap along a depression direction of the at least one surface depression.

[0021] The shape of the notch may vary based on the internal pressure of the external material.

[0022] When the internal pressure of the external material increases, the notch portion may open.

[0023] The thickness of the notch portion along a direction in which the notch portion is recessed may be 40% or less of the thickness of the outer material.

[0024] According to an embodiment, a battery cell may include: an electrode assembly including a cathode, an anode, and a separator disposed between the cathode and the anode, the separator physically separating the cathode from the anode but allowing ion flow; and an external material including at least one region having reduced tensile strength compared to the rest of the external material.

[0025] The at least one region with reduced tensile strength may form an indentation in the remaining outer material. The at least one region with reduced tensile strength may be formed in a predetermined region of the outer material by laser heating the predetermined region. In an embodiment, the predetermined region may be a region of reduced thickness compared to the remaining outer material.

[0026] In addition, the manufacturing method of the battery cell of the present disclosure includes: a heating operation of heating one region of the exterior material; and a notching operation of forming a notched portion in the one region of the heated exterior material.

[0027] In the heating operation, the external material may be heated by irradiating the first laser.

[0028] The first laser may be a diode laser.

[0029] In the notch operation, the notch portion may be formed by irradiating a second laser having a pulse width different from that of the first laser.

[0030] The manufacturing method of the battery cell may further include a vent forming operation of forming the vent by pressurizing at least one of an inner surface of the exterior material and an outer surface of the exterior material.

[0031] The manufacturing method of the battery cell may further include: an inserting operation of inserting the electrode assembly into the body part; and a covering operation of covering the opening part provided in the body part with the cover part.

[0032] According to one embodiment of the present disclosure, a battery cell in which internal pressure is controlled to have improved stability may be provided.

[0033] In addition, a method of manufacturing a battery cell in which a notch portion and an external material are manufactured as one body to have improved production efficiency may be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 and Figure 2 A battery cell according to an embodiment of the present disclosure is shown.

[0035] Figure 3An example of a method of manufacturing the exterior material of the present disclosure is shown.

[0036] Figure 4 and Figure 5 Heating of the outer material is shown.

[0037] Figure 6 The physical characteristics of the notch portion are shown.

[0038] Figures 7 to 10 Various embodiments of battery cells of the present disclosure are shown.

[0039] FIG. 11A to FIG. 11C Various embodiments of the notched portion of the present disclosure are shown.

[0040] Fig.12 The sequence of a method for manufacturing a battery cell according to one embodiment of the present disclosure is shown.

[0041] Fig.13 and Fig.14 Each operation of a method of manufacturing a battery cell according to one embodiment of the present disclosure is illustrated. DETAILED DESCRIPTION

[0042] Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings. This is merely illustrative, and the present disclosure is not limited to the specific embodiments described in an illustrative manner.

[0043] Specific terms used in this specification are for convenience of explanation only and are not intended to limit the illustrated embodiments.

[0044] For example, expressions such as “the same” and “the same as” indicate not only a strictly identical state but also a state where there is a difference in tolerance or degree of obtaining the same function.

[0045] For example, expressions indicating relative or absolute arrangement, such as "in a certain direction", "along a certain direction", "side by side", "vertical", "at the center", "concentric" or "coaxial", not only strictly indicate the arrangement but also indicate a relative displacement state with tolerance or an angle or distance for obtaining the same function.

[0046] In order to explain the present disclosure, the following description will be based on a spatial orthogonal coordinate system in which the X-axis, Y-axis and Z-axis are orthogonal to each other. Each axis direction (X-axis direction, Y-axis direction, Z-axis direction) refers to two directions in which each axis extends.

[0047] The X direction, the Y direction, and the Z direction mentioned hereinafter are for explanation so that the present disclosure can be clearly understood, and of course, these directions may be defined differently depending on the position of a reference object.

[0048] The terms "first, second and third" and the like are used before the components mentioned below only to avoid confusion about the components they refer to, and have nothing to do with the order, importance or master-slave relationship between the components, etc. For example, the invention including only the second component but not the first component can also be implemented.

[0049] As used in this specification, a singular expression includes a plural expression unless the context clearly dictates otherwise.

[0050] Figure 1 and Figure 2 A battery cell 10 according to an embodiment of the present disclosure is shown; and Figure 3 An example of a method of manufacturing the exterior material of the present disclosure is shown.

[0051] The battery cell 10 described in this specification refers to a secondary battery that can be repeatedly used by charging and discharging electric energy. For example, the battery cell may be a lithium secondary battery, but is not limited thereto.

[0052] The battery cell 10 may be classified into a pouch-type secondary battery, a prismatic secondary battery, or a cylindrical secondary battery according to the shape. Figure 1 , in this specification, for convenience of explanation, a prismatic secondary battery is shown as an example, but the present disclosure is not limited thereto.

[0053] The battery cell 10 of the present disclosure includes an electrode assembly 150, which includes a cathode, an anode, and a separator disposed between the cathode and the anode. The battery cell 10 may further include an external material 12, in which the electrode assembly 150 is accommodated. The external material may include: a first region 121, including a notch portion 20 disposed on an outer surface; and a second region 122, surrounding the first region. The tensile strength of the first region 121 is lower than the tensile strength of the second region 122.

[0054] The battery cell 10 includes an electrode assembly 150. Figure 2 The electrode assembly 150 may include a cathode 151, an anode 153, and a separator 152 disposed between the cathode and the anode, the separator 152 physically separating the cathode and the anode but allowing ions to pass through the structure of the separator. According to the method of stacking the cathode 151, the anode 153, and the separator 152, the electrode assembly 150 may be classified into a stacking type, a winding type, a stacking folding type, and a Z stacking type.

[0055] The type of the electrode assembly 150 included in the battery cell 10 of the present disclosure is not limited. In other words, the electrode assembly 150 included in the battery cell of the present disclosure may be an electrode assembly 150 manufactured in any one of a stacking type, a winding type, a stacking folding type, and a Z stacking type.

[0056] The cathode 151 and the anode 153 may include a current collector. The cathode 151 may include a cathode current collector, and the anode 153 may include an anode current collector. The current collector may include a known conductive material that does not cause a chemical reaction in the lithium secondary battery. For example, the current collector may include any one of stainless steel, nickel (Ni), aluminum (Al), titanium (Ti), copper (Cu), and alloys thereof, and may be provided in various forms such as a film, a sheet, a foil, and the like.

[0057] The cathode 151 and the anode 153 may include active materials. The cathode 151 may include a cathode active material, and the anode 153 may include an anode active material. The cathode active material may be a material into which lithium (Li) ions may be inserted and extracted, and the anode active material may be a material into which lithium ions may be adsorbed and extracted. For example, the cathode active material may be a lithium metal oxide, and the anode active material may be any one of a carbon-based material such as crystalline carbon, amorphous carbon, a carbon composite, and carbon fiber, a lithium alloy, silicon (Si), and tin (Sn).

[0058] In addition, the cathode 151 and the anode 153 may further include a binder and a conductive material to improve mechanical stability and conductivity, respectively.

[0059] The separator 152 may be configured to prevent an electrical short circuit between the cathode 151 and the anode 153 and allow ions to flow through the structure of the separator 152. The type of the separator is not particularly limited, but may include a porous polymer film. For example, the separator may include a porous polymer film or a porous nonwoven fabric.

[0060] The electrolyte may include an electrolyte solution. The electrolyte solution may be a non-aqueous electrolyte solution. The electrolyte solution may include a lithium salt and an organic solvent. The electrolyte solution may further include an additive. The additive may form a film on the cathode or anode through a chemical reaction inside the battery. For example, a cathode interface film may be formed on the cathode, and an anode interface film may be formed on the anode.

[0061] Reference Figure 2 , the outer material 12 may contain an electrode assembly 150 ( Figure 2 ). The electrode assembly and the electrolyte solution may be accommodated in the external material 12. The external material 12 may be provided with an external insulating layer made of a polymer material, an internal bonding layer, and a metal layer between the external insulating layer and the internal bonding layer. The external material 12 may include a material with high mechanical rigidity for protecting the battery cell 10 from external impact. For example, the external material 12 may include an aluminum layer.

[0062] In one embodiment, the outer material may be manufactured by an extrusion process. Figure 3, one area of ​​the outer material body 130 may be extruded to form an empty space in the inner area. Then, the outer material body 130 may be cut at preset intervals to manufacture a plurality of outer materials 12.

[0063] In another embodiment, the exterior material may be manufactured by a stamping process. As long as the exterior material can protect the battery from external impact, the method of manufacturing the exterior material is not particularly limited.

[0064] The exterior material 12 may include a body part 13 accommodating the electrode assembly and a cover part 14 covering the body part 13. The cover part 14 may include a cell tab 11 electrically connecting the electrode assembly to the outside.

[0065] Reference Figure 2 The main body 13 may include an open opening 15. The main body 13 may be open on both surfaces. In the main body 13, two opposite surfaces may be open respectively. Figure 2 , both surfaces of the main body 13 may be open toward the Y direction. The electrode assembly and the electrolyte may be accommodated inside the external material 12 through the opening 15. For example, the opening 15 may be set in a hexahedral shape so that both surfaces may be open along the Y direction. The cover 14 may cover the two open surfaces of the main body 13. The main body 13 and the cover 14 may be combined to close the accommodation space of the external material 12.

[0066] The cover parts 14a, 14b may cover the body part 13. In other words, the cover parts 14a, 14b may cover both open surfaces of the body part 13 to protect components accommodated in the body part 13. The body part 13 and the cover parts 14a, 14b may be coupled and sealed to each other.

[0067] The battery cell 10 may further include a cell tab 11 protruding to the outside of the external material 12 to be electrically connected to the outside. The cell tab 11 may be disposed in the cover portion 14. The battery cell 10 may include a plurality of cover portions 14a, 14b and a plurality of cell tabs 11a, 11b. Each cell tab 11a, 11b may be disposed on the plurality of cover portions 14a, 14b.

[0068] The cell tabs 11 (11a, 11b) may each be connected to a cathode and an anode of the battery cell 10. The cell tabs 11 may include a cathode tab 11a connected to a cathode and an anode tab 11b connected to an anode.

[0069] Reference Figure 1 and Figure 2, the battery cell 10 may include a notch portion 20 provided on the surface of the external material 12. The notch portion 20 may be provided on the outer surface of the external material 12. The notch portion 20 may be provided in the form of a groove or an indentation from the outer surface of the external material 12 toward the inside. In other words, the notch portion 20 may be provided in the form of a groove or an indentation recessed from the outer surface of the external material 12 toward the inside.

[0070] The battery cell 10 of the present disclosure can adjust the internal pressure through the notch portion 20. The battery cell 10 can be used multiple times by repeatedly charging and discharging. The internal pressure of the battery cell 10 may increase due to the gas generated in the process. When the gas continues to remain without being discharged, the battery cell 10 has a risk of explosion. Therefore, in order to safely use the battery cell 10, it is necessary to appropriately adjust the pressure of the battery cell 10.

[0071] The notch portion 20 may be provided on one side of the external material 12 so that gas may be discharged through the notch portion 20. In other words, the shape of the notch portion 20 may be changed based on the internal pressure of the external material 12, and when the internal pressure of the external material 12 increases and reaches the rupture pressure, the notch portion 20 may be opened. When the internal pressure of the external material 12 is lower than the rupture pressure, the shape of the notch portion 20 may be maintained. When the internal pressure of the external material 12 increases to above the rupture pressure due to continuous use of the battery cell, the shape of the notch portion 20 may be changed, and more specifically, the notch portion 20 may be opened so that the gas inside the external material 12 may be discharged to the outside, thereby reducing the internal pressure.

[0072] In the illustrated embodiment, a single notch portion 20 is shown. However, the present invention is not limited thereto. Therefore, in an embodiment, more than one notch portion 20 may be provided. Having more than one notch portion 20 may allow the pressure of the battery cell 10 to be quickly reduced to prevent the battery cell 10 from exploding. The notch portion 20 may be provided in the main body portion 13. The notch portion 20 may be formed integrally within the main body portion 13. For example, the notch portion 20 may be formed in a preset area of ​​the main body portion 13 by laser processing, rather than being manufactured separately and then joined to the main body portion 13.

[0073] Figure 4 and Figure 5 Heating the outer material to form the notch portion is shown. Figure 6 The physical characteristics of the formed notch portion are shown.

[0074] Reference Figure 4 , the exterior material 12 may include: a first region 121 including a notch portion; and a second region 122 surrounding the first region. The notch portion may be provided in the first region 121. In other words, the notch portion may be formed in a preset first region of the exterior material.

[0075] The second region may refer to a region outside the first region in the external material. The second region may be located on the same surface of the external material as the first region forming the notch portion. In other words, the first region and the second region may form one surface of the external material. The first region 121 may include the notch portion, and the second region 122 may refer to a region not including the notch portion.

[0076] The first region 121 and the second region 122 of the battery cell 10 may have different physical properties. To this end, the first region 121 may be heated. The first region 121 of the exterior material 12 may be heated to change the physical properties of the first region 121. For example, the first region 121 may be heated to a temperature of 200°C or higher within 5 seconds.

[0077] The heating of the first region 121 may be performed using a laser. However, the method of heating the first region 121 is not limited. When a laser is used, the outer surface of the outer material can be heated without difficulty. In this way, the user can accurately heat the desired position and improve manufacturing efficiency. Figure 4 and Figure 5 , laser may be used to heat one surface of the exterior material 12. The laser LA1 may be used to heat a preset first area 121 on the outer surface of the exterior material 12.

[0078] For example, refer to Figure 4 , the outer surface of the bidirectional battery cell 10 with both surfaces of the main body 13 open can be heated by laser. Figure 5 , the outer surface of the one-way battery cell 10 with one surface opened can be heated by laser. One surface of the external material can be easily heated using laser.

[0079] As the laser, a fiber laser or a diode laser can be used.

[0080] The wavelength of the laser may be in the range of 780nm to 2200nm. The laser may be used as a fiber laser. The fiber laser has a high peak power and is therefore capable of cutting or processing substrates. In addition, the fiber laser has a small beam size and therefore has a high energy density and is capable of delivering energy concentratedly to a narrow area.

[0081] Diode lasers with wavelengths in the range of 810nm to 1064nm can also be used. Diode lasers have lower peak power than fiber lasers, but they are able to deliver energy with minimal damage to the substrate. Therefore, diode lasers can be used to heat the substrate. In addition, the beam size of diode lasers is larger than that of fiber lasers, allowing energy to be delivered evenly over a wider area.

[0082] Reference Figure 6 In the first region of Example 1, a diode laser is used to heat the external material, and in the first region of Example 2, a fiber laser is used to heat the external material.

[0083] By heating, the tensile strength of the exterior material 12 can be changed. The tensile strength of the first region 121 and the tensile strength of the second region 122 can be different. The tensile strength of the first region 121 can be set lower than the tensile strength of the second region 122. In other words, the first region 121 of the exterior material 12 including the notch portion can be broken by a lower pressure than the second region 122 not including the notch portion.

[0084] The tensile strength of the external material can be measured using the ASTM D638 method or the ISO 527 method. For measurement, a specimen of the external material that has not been heat-treated, that is, the second region of the external material, is prepared. For comparison, a specimen of the heated external material is prepared. For example, a specimen heated by a diode laser (Example 1) and a specimen heated by a fiber laser (Example 2) are prepared. Each specimen can be cut into Type 4 or Type 5 to measure the tensile strength.

[0085] The tensile strength of the first region 121 may be set to be 80% or less of the tensile strength of the second region 122. Figure 6 , the tensile strength of the second region 122 may be 151 MPa, and the tensile strength of the first region 121 of Example 1 may be 111 MPa. The tensile strength of the first region 121 may be set to 80% or less of the tensile strength of the second region 122.

[0086] Since the tensile strength of the first region 121 is set to 80% or less of the tensile strength of the second region 122, even when the rupture pressure is reached, the risk of the second region 121 rupturing can be reduced, and only the first region 121 may rupture.

[0087] When the internal pressure of the battery cell increases and reaches the rupture pressure, the notch portion included in the first region 121 may be opened. The rupture pressure may be equal to the tensile strength of the first region 121. Since the tensile strength of the second region 122 is higher than the rupture pressure, the shape of the second region 122 may be maintained.

[0088] The elongation of the outer material may be changed by heating. The elongation of the first region 121 may be set to be different from the elongation of the second region 122. The elongation of the first region 121 may be greater than the elongation of the second region 122. In other words, the first region 121 may be elongated more than the second region 122. Here, the elongation may refer to the elongation at the yield point.

[0089] As described above, the elongation of the external material may be measured using the ASTM D638 method or the ISO 527 method.

[0090] The elongation of the first region 121 may be 300% or more of the elongation of the second region 122. Figure 6 , the elongation of the first region 121 of Example 1 may be 26.2, and the elongation of the second region 122 may be 7.65.

[0091] Since the elongation of the first region 121 is set to 300% or more of the elongation of the second region 122, when the pressure increases, the first region 121 may be elongated, and the change in the shape of the second region 121 may be small.

[0092] In an embodiment, the first region 121 may have a lower tensile strength and a higher elongation than the second region 122. In other words, when the pressure of the battery cell increases, the first region 121 is elongated, and when the pressure inside the battery cell reaches the fracture pressure, the notch portion provided in the first region 121 may be fractured first to be opened. In this way, the internal pressure can be adjusted while maintaining the shape of the battery cell.

[0093] Figures 7 to 10 Various embodiments of battery cells of the present disclosure are shown.

[0094] Reference Figure 7 The notch portion 20 may be formed by being recessed from the outer surface of the outer material 12 to the inner surface. At least a portion of the notch portion 20 may be formed to extend in one direction from the inner surface. In this way, the two surfaces of the notch portion 20 are spaced apart so that the gas inside can be easily discharged.

[0095] The depth of the recessed portion 20 may be 60% or more of the thickness of the outer material 12. Figure 7 , the thickness L1 of the exterior material 12 formed with the notch portion 20 may be 40% or less of the thickness L2 of the exterior material 12 not formed with the notch portion 20 .

[0096] The first region is not limited to a specific region as long as it can include a notch portion. Figure 8 The first region may extend along the X direction from one surface of the main body portion where the notch portion is provided.

[0097] Reference Fig. 9 , the battery cell of the present disclosure may further include a vent 30. The vent 30 may be formed by a depression of at least one of the inner surface of the outer material 12 and the outer surface disposed in a direction opposite to the inner surface. The first region may include the vent. In other words, the vent may be formed in a preset first region.

[0098] The notch portion and the vent portion may be positioned to overlap along the concave direction of the vent portion concave. In other words, the notch portion 20 may be positioned in the vent portion 30. The vent portion 30 serves to make the thickness of the exterior material 12 thinner. In this way, when the internal pressure of the battery cell 10 increases, the notch portion 20 may be easily opened.

[0099] Due to the presence of the notch portion 20 and the vent portion 30, the thickness of the exterior material 12 can be formed to be thinner in the preset first region 121 than in the remaining second region 122. In this way, when the internal pressure of the battery cell 10 increases and reaches the fracture pressure, the notch portion 20 can be opened to release the pressure and prevent the battery cell 10 from exploding.

[0100] The vent portion 30 may be formed integrally with the exterior material 12. As described above, like the notch portion 20, the vent portion 30 may not be manufactured separately but may be formed integrally with the exterior material 12. For example, the vent portion 30 may be formed by mechanical cutting or laser etching.

[0101] Refer again Fig. 9 , the width of the first region 121 and the width of the exhaust portion 30 may be set to be the same. Fig. 9 The width of the vent portion 30 may be defined as the distance from the depression start point P1 of the vent portion to the depression end point P2 of the vent portion along the X direction. The area between the depression start point P1 and the depression end point P2 may be heated so that the vent portion 30 may be positioned to overlap the first region 121.

[0102] In this way, the possibility of the notch portion 20 breaking earlier than other regions of the battery cell can be increased. In other words, when the first region 121 is heated to change its physical properties and reduce its thickness to be thinner than the remaining regions of the outer material 12, the notch portion 20 can be opened first when the internal pressure increases.

[0103] In another embodiment, the width of the exhaust portion 30a may be set to be longer than the width of the first region 121. Fig.10 , it is possible to heat only the portion from the depression starting point P1 to the depression end point P2 where the exterior material 12 starts to be depressed. In this way, when the pressure increases, the notch portion can be opened first.

[0104] The notch portion 20 may be made of the same material as the outer material 12. For example, the notch portion 20 may include an inner adhesive layer, an outer insulating layer, and a metal layer. In this way, the notch portion 20 may perform the same function as the outer material 12. For example, the notch portion 20 may protect the electrode assembly from external impact.

[0105] FIG. 11A to FIG. 11CVarious embodiments of the notched portion of the present disclosure are shown.

[0106] The notch portion 20 can be provided in various shapes. Fig.11A , the notch portion 20 may be configured as a line whose central area extends in one direction and has an arc at one end and the other end. Fig. 11B , the notch portion 20 may be configured such that the central region extends in one direction and one end and the other end are straight lines. Fig. 11C , the notch portion 20 may have a central area extending in one direction, and may further include a line having an arc shape. The shape of the notch portion 20 is not limited as long as the notch portion 20 can be opened on the outer surface of the outer material.

[0107] Hereinafter, a method of manufacturing the battery cell 10 according to the present disclosure will be described in detail.

[0108] Fig.12 The sequence of the method for manufacturing a battery cell according to an embodiment of the present disclosure is shown. Fig.13 and Fig.14 Each operation of a method of manufacturing a battery cell according to one embodiment of the present disclosure is illustrated.

[0109] Reference Fig.12 , the manufacturing method of the battery cell according to the present disclosure includes: a heating operation S30 of heating one region of the exterior material; and a notching operation S50 of forming a notch portion in the one region of the heated exterior material.

[0110] Reference Fig.13 In the manufacturing method of the present disclosure, the first region 121 may be formed by heating a region of the external material through a heating operation S30 of heating a region of the external material. In the heating operation S30 of heating a region of the external material, the physical properties of the external material may be changed. In an embodiment, in the heating operation S30 of heating a region of the external material, the first region 121 whose physical properties are changed by heating the external material and the second region 122 surrounding the first region 121 may be formed. The first region 121 and the second region 122 are not formed by separate welding or the like, but may be formed as one body.

[0111] In the heating operation S30 of heating one area of ​​the external material, the external material may be heated by irradiating the first laser LA1. The type of laser is not particularly limited as long as it can heat the external material. For example, the first laser may be a diode laser.

[0112] Reference Fig.14In the notch operation S50 of forming the notch portion in one area of ​​the heated outer material, the notch portion 20 may be formed by irradiating the laser to a preset area of ​​the outer material 12. The notch portion 20 may be formed by irradiating the laser to one area of ​​the body portion 13 and the cover portion 14. The preset area may be the first area 121 (see Fig.13 ).

[0113] In the notch forming operation S50, the notch 20 can be formed by irradiating laser to the region of the external material heated by the heating operation S30 of heating one region of the external material. The notch 20 can be formed at a precise position using laser, and the manufacturing efficiency can be improved due to the simple process.

[0114] In the notch operation S50 of forming the notch portion, the notch portion 20 may be formed by irradiating the second laser LA2. In other words, the pulse width of the second laser used in the notch operation S50 of forming the notch portion may be different from the pulse width of the first laser used in the heating operation. The pulse width of the second laser used in the notch operation S50 of forming the notch portion may be shorter than the pulse width of the first laser used in the heating operation S30 of heating one area of ​​the external material.

[0115] Since the shorter the pulse width, the higher the peak power, the second laser used in the notching operation S50 of forming the notched portion can form a groove by minimizing the thermal effect on the external material and prevent damage to the external material. For example, thermal damage to the external material can be prevented. The laser used in the heating operation S30 can heat the external material.

[0116] In the manufacturing method of the present disclosure, an inserting operation S70 of inserting the electrode assembly may be performed after the notching operation S50 of forming the notch portion. The electrode assembly may be inserted into the body portion 13 through the inserting operation S70 of inserting the electrode assembly.

[0117] In the manufacturing method of the present disclosure, a covering operation S90 of covering the opening portion provided in the body portion with the cover portion may be performed after the inserting operation S70 of inserting the electrode assembly. After the electrode assembly is inserted into the body portion 13, the cover portion 14 may cover the body portion 13. In this way, the electrode assembly may be stably accommodated in the exterior material 12.

[0118] In the present specification, an operation of forming a notch portion formed integrally with the main body portion 13 by performing a heating operation S30 of heating an area of ​​the external material and a notch operation S50 of forming the notch portion in an area of ​​the main body portion 13 of the external material is described by way of example, however, optionally, a notch formed integrally with the cover portion 14 may also be formed in an area of ​​the cover portion 14 of the external material.

[0119] Reference Fig.12 The manufacturing method of the battery cell of the present disclosure may further include an operation S10 of forming a vent portion by pressurizing at least one of an inner surface of the external material and an outer surface of the external material. In operation S10, the vent portion 30 (see Fig. 9 ) may be formed on the inner surface of the outer material 12 (see Fig. 9 ) and at least one of the outer surfaces of the outer material 12. For example, when the main body 13 is manufactured by an extrusion process, the exhaust portion may be formed by mechanical cutting or laser etching.

[0120] In one embodiment, in the manufacturing method of the present disclosure, the operation S10 of forming the vent portion may be performed before the notch operation S50 of forming the notch portion. After the pressurizing part presses both surfaces of the exterior material 12 to form the concave vent portion 30, the notch portion 20 may be formed by irradiating laser.

[0121] In another embodiment, in the manufacturing method of the present disclosure, the operation S10 of forming the vent portion and the notch operation S50 of forming the notch portion can be performed simultaneously. When the outer material 12 is pressurized by the pressurizing part protruding at one side to form the notch, one area of ​​the outer material 12 can be recessed to form the vent portion 30.

[0122] However, according to an embodiment, operation S10 of forming the vent may be omitted.

[0123] The present disclosure can be modified and implemented in various forms, and the scope of the present disclosure is not limited to the above-mentioned embodiments. Therefore, if the modified embodiment includes the components of the present disclosure, the modified embodiment should be regarded as falling within the scope of the rights of the present disclosure.

Claims

1. A battery cell, comprising: An electrode assembly, comprising a cathode, an anode, and a separator disposed between the cathode and the anode; as well as An external material, wherein the electrode assembly is accommodated in the external material, wherein The exterior material includes a first region having a notch portion provided on an outer surface, and a second region surrounding the first region, and the tensile strength of the first region is set to be lower than the tensile strength of the second region.

2. The battery cell according to claim 1, wherein: The notch portion is provided in the form of a groove sunken inwardly from an outer surface of the exterior material.

3. The battery cell according to claim 1, wherein: The tensile strength of the first region is 80% or less of the tensile strength of the second region.

4. The battery cell according to claim 1, wherein: The elongation rate of the first region is set to be different from the elongation rate of the second region.

5. The battery cell according to claim 4, wherein: The elongation of the first region is greater than the elongation of the second region.

6. The battery cell according to claim 5, wherein: The elongation of the first region is 300% or more of the elongation of the second region.

7. The battery cell according to claim 1, wherein: The exterior material further includes: a body part accommodating the electrode assembly; and a cover part including a cell tab electrically connecting the electrode assembly to the outside and covering the body part, wherein the notch part is provided in the body part.

8. The battery cell according to claim 1, wherein: The notch portion is formed integrally with the outer material.

9. The battery cell according to claim 1, wherein: The notch portion includes the same material as the outer material.

10. The battery cell according to claim 1, wherein: The exterior material further includes a vent portion formed by a depression of at least one of an inner surface and an outer surface disposed in a direction opposite to the inner surface, and the notch portion and the vent portion are positioned to overlap along a depression direction of the at least one surface depression.

11. The battery cell according to claim 1, wherein: The shape of the recess changes based on the internal pressure of the outer material.

12. The battery cell according to claim 11, wherein: When the internal pressure of the external material increases, the notch portion opens.

13. The battery cell according to claim 2, wherein: The thickness of the notch portion in a direction in which the notch portion is recessed is 40% or less of the thickness of the exterior material.

14. A method for manufacturing a battery cell, the battery cell comprising: An electrode assembly having a cathode, an anode, and a separator disposed between the cathode and the anode; a main body portion, wherein the electrode assembly is accommodated in the main body portion; and a cover portion, covering the main body portion, the manufacturing method comprising: Heating operations, heating an area of ​​the external material; as well as The notching operation forms a notched portion in an area of ​​the heated exterior material.

15. The method for manufacturing a battery cell according to claim 14, wherein: In the heating operation, the external material is heated by irradiating the first laser.

16. The method for manufacturing a battery cell according to claim 15, wherein: The notch portion is formed by irradiating a second laser having a pulse width different from a pulse width of the first laser.

17. The method for manufacturing a battery cell according to claim 14, further comprising: The vent forming operation forms the vent by pressurizing at least one of the inner surface of the exterior material and the outer surface of the exterior material.

18. The method for manufacturing a battery cell according to claim 14, further comprising: Inserting operation, inserting the electrode assembly into the main body; and a covering operation of covering the opening provided in the main body with the cover.

19. A battery cell comprising: an electrode assembly including a cathode, an anode, and a separator disposed between the cathode and the anode, the separator physically separating the cathode from the anode but allowing ion flow; as well as The outer material includes at least one region having reduced tensile strength compared to the remainder of the outer material.

20. The battery cell according to claim 19, wherein: The at least one region of reduced tensile strength forms an indentation in the remaining outer material.

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