Battery cell and manufacturing method of battery cell

Abstract

A battery cell according to an embodiment of the present disclosure may comprise: a case including an opening formed on one surface, through which an electrode assembly is accommodated inside the case, and an opposite surface facing the opening; a cover plate coupled to the housing to close the opening portion; and an exhaust part formed in a groove form on the facing surface.

Description

Technical Field

[0001] The present disclosure relates to a secondary battery, and in particular, to a battery cell and a method for manufacturing the battery cell. Background Art

[0002] Secondary batteries convert electrical energy into chemical energy and store it, allowing for repeated use through charging and discharging. Due to their economical and environmentally friendly features, they are widely used in various industries. Among secondary batteries, lithium secondary batteries (Lithium Secondary Batteries) are particularly popular in various industries, including portable devices requiring high energy density.

[0003] Lithium-ion batteries operate on the principle of electrochemical redox reactions. Specifically, they generate electricity through the movement of lithium ions, and charging occurs in the reverse process. In lithium-ion batteries, the phenomenon of lithium ions escaping from the negative electrode (anode) and moving through the electrolyte and separator to the positive electrode (cathode) is called discharge. The reverse process is called charging.

[0004] During repeated charging and discharging, secondary batteries may experience swelling, which can increase internal pressure and generate a large amount of heat. This swelling can cause explosions or fires, and therefore a solution for regulating the internal pressure of secondary batteries is needed. Summary of the Invention

[0005] (1) Technical issues to be resolved

[0006] According to one aspect of the present disclosure, a battery cell is provided that can adjust internal pressure to improve stability.

[0007] According to another aspect of the present disclosure, a battery cell is provided that adjusts internal pressure by deforming the shape of a vent portion.

[0008] According to another aspect of the present disclosure, there is provided a battery cell in which the vent is formed in a ring shape surrounding an electrode terminal.

[0009] The present disclosure can be widely applied to electric vehicles, battery charging stations, and other green technologies such as solar and wind power generation using batteries. Furthermore, the present disclosure can be applied to eco-friendly electric vehicles and hybrid vehicles, which aim to prevent climate change by reducing air pollution and greenhouse gas emissions.

[0010] (2) Technical solution

[0011] According to an embodiment of the present disclosure, a battery cell may include: a shell, including an opening formed on one side and an opposite side facing the opening, through which the electrode assembly is accommodated inside the shell; a cover plate, coupled to the shell to close the opening; and a vent, formed in a groove form on the opposite side, the ten-point average roughness of the vent surface being higher than the ten-point average roughness of an area adjacent to the vent.

[0012] The exhaust portion may be formed in a ring shape on a surface facing the outside of the housing among both side surfaces of the opposing surfaces.

[0013] The battery cell may further include a first current collecting plate disposed inside the case between the opposing surface and the electrode assembly and electrically connected to the electrode assembly.

[0014] The battery cell may further include an electrode terminal electrically connected to the first collector plate and exposed to the outside through the opposite surface.

[0015] The shape of the exhaust portion may be deformed according to the internal pressure of the housing.

[0016] When the internal pressure of the housing increases, at least a portion of the vent portion may be opened.

[0017] The thickness of the groove may be 1 / 6 or less of the thickness of the opposing surface.

[0018] The structure of the region adjacent to the vent portion may have a morphology of a plurality of crystal grains, the structure of the region adjacent to the vent portion may include an equiaxed structure, or the plurality of crystal grains may have isotropy.

[0019] At least a portion of any one of the plurality of dies may be cut.

[0020] The exhaust portion may be formed by laser and may include a resolidified layer formed by solidifying a portion of the region after being heated.

[0021] The ten-point average roughness of the exhaust portion surface may exceed 20.

[0022] According to an embodiment of the present disclosure, a battery cell may include: an electrode assembly including a first electrode (positive electrode), a separator, and a second electrode (negative electrode); a shell including an opening formed on one side and an opposite side facing the opening, wherein the electrode assembly is accommodated inside the shell through the opening and electrically connected to the second electrode; a cover plate coupled to the shell to close the opening; and a vent formed in a groove shape on the opposite side.

[0023] The battery cell may further include an electrode terminal electrically connected to the first electrode and exposed to the outside through the opposite surface.

[0024] The exhaust portion may be formed in a ring shape surrounding the electrode terminal, on a surface facing the outside of the case among both side surfaces of the opposing surfaces.

[0025] The electric wire may further include a first collector plate electrically connected to the first electrode between the opposing surface and the first electrode; and a second collector plate electrically connected to the second electrode between the cap plate and the second electrode inside the case.

[0026] According to a method for manufacturing a battery cell according to an embodiment of the present disclosure, the battery cell includes a shell, the shell includes an opening portion formed on one side and an opposite surface facing the opening portion, and an electrode assembly including a first electrode, a diaphragm, and a second electrode is accommodated inside the shell. The method for manufacturing the battery cell may include: a step of processing the opposite surface to form a vent portion.

[0027] The step of forming the exhaust portion may include: forming a starting groove of the exhaust portion by laser; and etching the opposite surfaces by laser starting from the starting groove so that the exhaust portion has a ring shape.

[0028] After forming the vent, the steps may include: combining a first collector plate with the first electrode and combining a second collector plate with the second electrode; and inserting the electrode assembly into the case through the opening so that the first collector plate faces the opposing surface.

[0029] After the step of inserting the electrode assembly into the case, the method may further include coupling a cap plate to the case to close the opening.

[0030] According to an embodiment of the present disclosure, a battery cell may include: a shell, including an opening formed on one side and an opposite side facing the opening, through which the electrode assembly is accommodated inside the shell; a cover plate, coupled to the shell to close the opening; and a vent, formed in a groove form on the opposite side, wherein a surface of the vent may be rougher than a surface of an area adjacent to the vent.

[0031] (3) Beneficial effects

[0032] According to one embodiment of the present disclosure, the internal pressure may be adjusted to improve stability.

[0033] According to another embodiment of the present disclosure, the internal pressure may be adjusted by deforming the shape of the vent portion.

[0034] According to another embodiment of the present disclosure, the vent is formed in a ring shape surrounding the electrode terminal, thereby not causing interference and forming a restriction when welding the electrode terminal. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a diagram for explaining a battery cell according to an embodiment.

[0036] Figure 2 is an exploded view for explaining a battery cell according to an embodiment.

[0037] Figure 3 is a diagram for explaining an electrode assembly according to an embodiment.

[0038] Figure 4 is a diagram showing a wound state of an electrode assembly according to an embodiment.

[0039] Figure 5 is a diagram for explaining a cross section of a battery cell according to an embodiment.

[0040] Figure 6 It is a diagram for explaining the opposing surface portion of a battery cell according to an embodiment.

[0041] Figure 7 It is a diagram for explaining a cross section of an exhaust portion according to an embodiment.

[0042] Figure 8 It is a diagram for explaining a method of manufacturing a battery cell according to an embodiment.

[0043] Description of reference numerals:

[0044] 100: battery cell 110: shell

[0045] 120: Cover plate 130: Electrode terminal

[0046] 135: Insulation washer 141: First collector plate

[0047] 142: Second collector plate 160: Electrode assembly

[0048] 170: Electrode 180: Diaphragm DETAILED DESCRIPTION

[0049] Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings, but this is merely exemplary, and the present disclosure is not limited to the specific embodiments described exemplarily.

[0050] Figure 1 is a diagram for explaining a battery cell according to an embodiment.

[0051] Reference Figure 1 The battery cell 100 according to the embodiment may include a case 110 , a cap plate 120 , and a vent 190 .

[0052] The battery cell 100 may be a secondary battery that can be charged and discharged multiple times.

[0053] For example, the secondary battery can be one of a lithium cobalt battery, a lithium high nickel battery, a lithium iron phosphate battery, a lithium ion battery, a lithium polymer battery, a lithium sulfur battery, a nickel metal hydride battery, a nickel cadmium battery, a sodium battery, and an all-solid-state battery, but is not limited thereto and can also be transformed into various types of secondary batteries.

[0054] The housing 110 may include an opening 114 formed on one side and an opposite side 111 facing the opening 114. The housing 110 may accommodate the electrode assembly 160 therein through the opening 114. The housing 110 may accommodate a current collector 140 electrically connected to the electrode assembly 160.

[0055] Similar to the opening 114, the opposite surface 111 may be open, so the housing 110 may be cylindrical with two open sides. Alternatively, unlike the opening 114, the opposite surface 111 may be closed, so the housing 110 may be in a "U" shape with only one side having the opening 114 open.

[0056] For example, the housing 110 may have a container shape with a portion opened.

[0057] In an embodiment, the housing 110 may include various metals such as iron, aluminum, alloys of these metals, plastic, ceramics, or carbon.

[0058] In an embodiment, the housing 110 may include opposing surfaces 111 and side surfaces 113 .

[0059] The opposing surface 111 may extend from the upper end or the lower end of the side surface portion 113. Here, the upper end and the lower end may be either end in the height direction (e.g., the Z-axis direction). For example, the opposing surface 111 may extend from the upper end of the side surface portion 113. In this embodiment, the housing 110 is provided with the opposing surface 111 at the upper end and the opening 114 at the lower end.

[0060] At least a portion of the opposing surface 111 may be formed as a flat surface with no height variation in a horizontal direction (eg, X-axis direction, Y-axis direction). The area of ​​the opposing surface 111 excluding the exhaust portion 190 may be formed as a flat surface.

[0061] The shape of the opposing surface 111 in the XY plane can be circular, but is not limited thereto. It can also be deformed into an ellipse, triangle, quadrilateral, polygon, etc. The side surface portion 113 can extend from the edge of the opposing surface 111 in the height direction (e.g., the Z-axis direction). In an embodiment, the opposing surface 111 and the side surface portion 113 can be formed integrally or separately.

[0062] In an embodiment, the side surface portion 113 may be formed with a beading portion 115. The beading portion 115 may be a portion of the side surface portion 113 that is bent toward the inside surrounded by the side surface portion 113. In an embodiment, the housing 110 may be formed with an opening portion 114 having one end open.

[0063] The openings 114 may be formed on opposite sides of the opposing surface 111 in a height direction (eg, a Z-axis direction).

[0064] For example, if the facing surface 111 is formed at the upper end of the side surface portion 113, the opening portion 114 may be formed at the lower end of the side surface portion 113. The electrode assembly 160 and the current collector plate 140 may be inserted into the interior of the case 110 through the opening portion 114. Thereafter, the bead portion 115 may be formed in a region of the side surface portion 113 adjacent to the opening portion 114.

[0065] The cover plate 120 may seal the housing 110. The cover plate 120 may be coupled to the housing 110 to close the opening portion 114.

[0066] In an embodiment, after the electrode assembly 160 and the collector plate 140 are accommodated inside the case 110 , the cap plate 120 may be coupled to the case 110 .

[0067] That is, the housing 110 and the cover plate 120 may surround the outer sides of the electrode assembly 160 and the current collector plate 140. In an embodiment, the shape of the cover plate 120 and the housing 110 combined together may be cylindrical. However, this is only one embodiment, and the shape of the cover plate 120 and the housing 110 combined together may be modified to various shapes such as a prism or a hexahedron.

[0068] In an embodiment, the cover plate 120 may be located on an opposite side of the opposing surface 111. For example, if the opposing surface 111 is formed at an upper end of the side surface portion 113, the cover plate 120 may be coupled to a lower end of the side surface portion 113.

[0069] In an embodiment, the opposing surface 111 may include a vent portion 190 formed in a groove shape.

[0070] The exhaust portion 190 may be formed on the surface facing the outside of the housing 110, of both side surfaces of the opposing surface 111. The exhaust portion 190 may be formed in a recessed shape on the opposing surface 111. The exhaust portion 190 may be thinner or lower than adjacent areas.

[0071] In an embodiment, the vent portion 190 may be formed in a ring shape or a doughnut shape on the opposing surface 111. The vent portion 190 may be connected along the outer circumference of the opposing surface 111 and may have a continuous form.

[0072] The opposite surface 111 may be formed with a vent portion 190 having a relatively thin thickness or a relatively low height. When the internal pressure of the housing 110 increases, the vent portion 190 may be deformed before a region adjacent to the vent portion 190.

[0073] In an embodiment, the vent 190 may be formed at the opposite surface 111 to be spaced apart from the electrode terminal 130 exposed to the outside. The vent 190 may have a perimeter longer than that of the electrode terminal 130 and may be formed to surround the electrode terminal 130.

[0074] Figure 2 is an exploded view for explaining a battery cell according to an embodiment.

[0075] Reference Figure 2 The battery cell 100 according to the embodiment may include a case 110 , a cap plate 120 , an electrode assembly 160 , a collector plate 140 , an electrode terminal 130 , and an insulating gasket 135 .

[0076] Figure 2 This is a view of the battery cell viewed from the bottom up. Figure 2 The opposite surface 111 formed at the upper end of the battery cell and including the vent 190 is not shown. Figure 2 FIG. 1 shows an opening 114 formed at the lower end of the battery cell.

[0077] In an embodiment, the electrode assembly 160 may include a first electrode 171, a second electrode 175, and a separator 180, which will be described later. Figure 3 and Figure 4 Detailed description in.

[0078] In an embodiment, the collector plate 140 may include at least one of a first collector plate 141 and a second collector plate 142. The first collector plate 141 may be disposed between the opposing surface 111 of the case 110 and the electrode assembly 160. The second collector plate 142 may be disposed between the cap plate 120 and the electrode assembly 160.

[0079] The collector plate 140 may be electrically connected to the electrodes of the electrode assembly 160 . To this end, the collector plate 140 may include a conductive material such as copper, gold, silver, or aluminum. The electrodes may include a first electrode 171 and a second electrode 175 .

[0080] In an embodiment, the first collector plate 141 and the second collector plate 142 may be electrically connected to different electrodes of the electrode assembly 160. For example, the first collector plate 141 may be electrically connected to the first electrode 171, and the second collector plate 142 may be electrically connected to the second electrode. In an embodiment, the first collector plate 141 may be electrically connected to the electrode terminal 130. The second collector plate 142 may be electrically connected to the housing 110 and / or the cap plate 120.

[0081] The first collector plate 141 may be disposed between the opposing surface 111 and the electrode assembly 160 within the case 110. The first collector plate 141 may be electrically connected to the first electrode 171 of the electrode assembly 160.

[0082] The second collector plate 142 may be disposed between the cap plate 120 and the electrode assembly 160 inside the case 110. The second collector plate 142 may be electrically connected to the second electrode of the electrode assembly 160.

[0083] In an embodiment, the electrode terminals 130 may be disposed on opposite sides of the cap plate 120 in the height direction (e.g., the Z-axis direction). The electrode terminals 130 may be electrically connected to the current collector plate 140 and may be exposed to the outside through the opposite surface 111. The electrode terminals 130 may be electrically connected to an external device. In other words, current may flow to the external device through the electrode terminals 130.

[0084] In an embodiment, the electrode terminal 130 may be inserted into the through-hole of the case 110 .

[0085] In an embodiment, the electrode terminal 130 may be a rivet. In an embodiment, a through hole may be formed in the opposing surface 111 of the housing 110. For example, the through hole may be formed through the center of the opposing surface 111. The electrode terminal 130 may be exposed to the outside through the center of the opposing surface 111.

[0086] In an embodiment, an insulating gasket 115 may be disposed between the housing 110 and the electrode terminal 130. For example, the insulating gasket 135 may be disposed between the opposing surface 111 of the housing 110 and the electrode terminal 130. The insulating gasket 135 may include an insulating material. The insulating material may include a material with low electrical conductivity such as a polymer or ceramic.

[0087] Figure 3 is a diagram for explaining an electrode assembly 160 according to an embodiment. Figure 4 is a diagram illustrating a wound state of the electrode assembly 160 according to an embodiment.

[0088] Figure 3 is an exploded view of a portion of the wound electrode assembly 160, Figure 4 FIG. 1 shows an electrode assembly 160 formed with a flag. Figure 3 and Figure 4 , the electrode assembly 160 according to the embodiment may include an electrode 170 and a separator 180 .

[0089] The electrode 170 may include a first electrode 171 and a second electrode 175. The first electrode 171 and the second electrode 175 may have different polarities. For example, the first electrode 171 may be a positive electrode and the second electrode 175 may be a negative electrode. As another example, the first electrode 171 may be a negative electrode and the second electrode 175 may be a positive electrode.

[0090] Electrode 170 may be a plate partially coated with an active material. In an embodiment, first electrode 171 may include a first uncoated portion 171a not coated with the first active material and a first coated portion 171b coated with the first active material. Second electrode 175 may include a second uncoated portion 175a not coated with the second active material and a second coated portion 175b coated with the second active material.

[0091] In an embodiment, the first non-coating portion 171a may be formed at an upper end of the first coating portion 171b, and the second non-coating portion 175a may be formed at a lower end of the second coating portion 175b.

[0092] When the first electrode 171 is a positive electrode, the first active material can be a positive electrode active material. When the second electrode 175 is a negative electrode, the second active material can be a negative electrode active material. The positive electrode active material can include at least one of lithium transition metal oxides, nickel-cobalt-manganese-based lithium oxides, and the like. The negative electrode active material can include at least one of carbon materials, lithium, lithium metal compounds, silicon, silicon compounds, tin, tin compounds, and the like. On the other hand, the above embodiment is only one embodiment, and the types of positive electrode active materials and negative electrode active materials are not limited and can be changed.

[0093] In an embodiment, the electrode 170 may further include an insulating coating portion 165 formed at a boundary between the uncoated portion and the coated portion. The insulating coating portion 165 may include an insulating material. The insulating coating portion 165 may improve the mechanical rigidity of the portion bent from the uncoated portion to form the flag portion 170f.

[0094] The separator 180 may include an inner separator 181 disposed between the first electrode 171 and the second electrode 175 and an outer separator 182 disposed outside. The separator 180 may include an insulating material. The separator 180 may block contact between the first electrode 171 and the second electrode 175 and electrically isolate the first electrode 171 from the second electrode 175.

[0095] The electrode assembly 160 may be wound. In an embodiment, the electrode 170 and the separator 180 may be wound around a central axis C in a stacked state. Here, the central axis C may be in the height direction (e.g., the Z-axis direction). For example, the outer separator 182, the first electrode 171, the inner separator 181, and the second electrode 175 may be wound around the central axis C in a stacked state.

[0096] Electrode 170 may include a flag portion 170f. In an embodiment, flag portion 170f may be defined as the region extending from the bent portion to the end portion when a portion of the uncoated portion is bent. In an embodiment, the uncoated portion may be bent at an angle of 90 degrees or less relative to the XY plane. In an embodiment, the uncoated portion may be notched into a plurality of slices. The plurality of slices may be bent sequentially from the innermost slice to the outermost slice.

[0097] The flag portion 170f may include a first flag portion 171f and a second flag portion 175f. For example, the first flag portion 171f may be formed by bending the first uncoated portion 171a of the first electrode 171 inwardly of the central axis C. The second flag portion 175f may be formed by bending the second uncoated portion 175a of the second electrode 175 inwardly of the central axis C.

[0098] Figure 5 is a diagram for explaining a cross section of a battery cell according to an embodiment.

[0099] exist Figure 5 In the embodiment, the upper end of the battery cell may be formed with an opposing surface 111, and the lower end may be provided with a cover plate 120 for closing the opening 114. For example, a side surface adjacent to the cover plate 120 may be formed with a curling portion 115 and contact the second collector plate 142.

[0100] The beading portion 115 can restrict the movement of the electrode assembly 160 or the second collector plate 142 inside the case 110. The beading portion 115 can prevent the electrode assembly 160 or the second collector plate 142 from being separated from the case 110. However, the present invention is not limited thereto and the beading portion 115 can also be omitted.

[0101] In an embodiment, the opposing surface may include a vent portion 190 that is at least partially opened under a predetermined pressure. The vent portion 190 may be formed in a groove shape on the opposing surface 111 , and the vent portion 190 may be thinner than adjacent areas.

[0102] The vent portion 190 may be a notch formed downward, i.e., inward, from the upper surface of the opposing surface 111. The cross-section of the vent portion 190 may have the shape of a notch. The vent portion 190 may be formed in a circular shape on the upper surface of the opposing surface 111. When viewed from above the opposing surface 111, the vent portion 190 may be formed in a circular shape. However, the shape of the vent portion 190 is not limited to this and may also be a quadrilateral or polygonal shape.

[0103] The vent portion 190 may have a pattern shape continuously connected on the opposite surface 111. For example, the vent portion 190 may have a shape of a continuous body in which straight lines or curved lines are connected to each other.

[0104] The exhaust portion 190 may be connected along a 360-degree direction with respect to the central axis C of the opposing surface 111 .

[0105] The vent portion 190 may be spaced apart from the electrode terminal 130 exposed to the outside through the opposing surface 111. The vent portion 190 may be formed between the outer periphery of the terminal and the outer periphery of the opposing surface 111. The vent portion 190 may be formed in a ring shape surrounding the electrode terminal.

[0106] Reference Figure 5 , the electrode assembly 160 can be wound around the central axis C.

[0107] The electrode assembly 160 may include a separator and an electrode. The electrode may include a flag portion 170f. In an embodiment, the battery cell 100 may further include an electrolyte. For example, the electrolyte may be a medium that transmits ions or current between the positive electrode and the negative electrode of the electrode assembly 160.

[0108] The second collector plate 142 may be electrically connected to the flag portion 170f of the electrode 170. Figure 3 and Figure 4 The first collector plate 141 may be electrically connected to the first flag portion 171F of the first electrode 171. In an embodiment, the first collector plate 141 may be electrically connected to the electrode terminal 130. The second collector plate 142 may be electrically connected to the second flag portion 175f of the second electrode 172.

[0109] In an embodiment, an insulating gasket 135 may be disposed between the opposing surface 111 of the case 110 and the electrode terminal 130 .

[0110] The insulating gasket 135 can block contact between the electrode terminal 130 and the housing 110. The insulating gasket 135 can electrically isolate the electrode terminal 130 from the housing 110. That is, the electrode terminal 130 and the housing 110 can have different polarities. For example, when the polarity of the electrode terminal 130 is (+), the polarity of the housing 110 can be (-).

[0111] Figure 6 1 is a diagram for explaining the opposing surface 111 portion of the battery cell according to the embodiment.

[0112] Figure 6 yes Figure 5 1 is a partial enlarged view for explaining the exhaust portion 190. The exhaust portion 190 can be formed in the form of a groove on the opposite surface 111 and can be formed by laser.

[0113] The vent 190 may be a region of the opposing surface 111 etched by laser. The height of the opposing surface 111 from the opposing surface 111 toward the opening 114 may be 0.6 mm. The height of the vent 190 is lower than that of the opposing surface 111 and may be 0.1 mm.

[0114] That is, the thickness of the facing surface 111 may be 0.6 mm, and the thickness of the vent portion 190 may be 0.1 mm.

[0115] In an embodiment, the thickness of the vent portion 190 may be less than 1 / 6 of the thickness of the opposing surface 111. The thickness of the vent portion 190 may be less than 20% of the thickness of the opposing surface 111. The vent portion 190 may be formed by compressing the opposing surface 111 to approximately 80% of the thickness of the opposing surface 111. The vent portion 190 may be formed by laser etching, which allows for greater flexibility in the thickness that can be processed compared to physical forging by stamping.

[0116] The shape of the vent portion 190 may be deformed according to the internal pressure of the housing 110. The vent portion 190 may be lower in height or thinner in thickness than the vent portion 190. When the internal pressure of the housing 110 rises, the vent portion 190 may be deformed before an area adjacent to the vent portion 190.

[0117] When the internal pressure of the housing 110 rises, at least a portion of the vent 190 can be opened. When the internal pressure of the housing 110 rises, at least a portion of the vent 190 can be ruptured. The vent 190 is formed in a ring shape on the opposite surface 111 and can be deformed even when the internal pressure of the housing 110 locally rises.

[0118] In an embodiment, the opposite surface 111 where the exhaust portion 190 is formed may be integrally formed with the side surface portion.

[0119] The opposite surface 111 may be formed by extending from the side surface toward the upper end. The opposite surface 111 may be formed of the same material as the side surface. Therefore, the opposite surface 111 may not be welded or physically combined with the side surface.

[0120] The housing 110 may be integrally formed except for the opening 114 formed on one side. The housing 110 may be formed in a "U" shape with one side open.

[0121] The thickness of the vent portion 190 may be smaller than that of the side portion. When the internal pressure of the housing 110 rises, the vent portion 190 may be deformed before the side portion.

[0122] Figure 7 1 is a diagram for explaining a cross section of the exhaust portion 190 according to the embodiment.

[0123] Figure 71 is an enlarged view of the exhaust portion 190 according to the embodiment. The exhaust portion 190 may be formed by being recessed on the upper surface of the opposite surface 111 toward the interior of the housing 110. The recessed depth of the exhaust portion 190 may be more than 80% of the thickness of the opposite surface 111. Figure 7 The thickness of the opposing surface 111 where the vent portion 190 is formed may be less than or equal to 20% of the thickness of the opposing surface 111 where the vent portion 190 is not formed.

[0124] Figure 7 This is a schematic diagram of a cross section of the opposing surface 111, captured using the electron backscatter diffraction (EBSD) analysis method. EBSD analysis uses an EBSD analyzer mounted on a scanning electron microscope to inject accelerated electrons into the sample and detect the electrons to analyze the material's orientation. This allows analysis of the crystal structure of the opposing surface 111.

[0125] The vent 190 can be formed by laser heating. It can include a resolidified layer 25 formed by solidifying a region of the overlapped portion after heating. The resolidified layer 25 can be a portion of the opposing surface 111 that changes color after solidification after heating. In an embodiment, the solidified region can be distinguished from other regions by color. The resolidified layer 25 can be formed outside the vent 190.

[0126] In an embodiment, the thickness of the resolidified layer 25 in the direction from the inside to the outside of the opposing surface 111 may be 5 μm (micrometers) or more, and more specifically, may be 3 μm or more.

[0127] More specifically, the resolidified layer 25 can be formed by melting and then resolidifying the opposing surface 111 using a pulsed laser with a pulse width of 1 nanosecond (ns) or greater. If a pulsed laser with a pulse width of less than 1 nanosecond (ns) is used, the resolidified layer 25 may not be formed.

[0128] The resolidified layer 25 may include vacancy defects. Specifically, the crystal structure of the resolidified layer 25 may include vacancy defects. Vacancy defects are a form of point defect in a crystal structure and can form in response to external conditions such as heat and pressure. Vacancy defects can be caused by atoms falling out of a lattice site, leaving a void or vacancy in the crystal lattice.

[0129] Therefore, a portion of the battery cell 100 of the present disclosure may be heated and cooled to form a resolidified layer 25 , and the resolidified layer 25 may include vacancy defects.

[0130] In an embodiment, the opposing surface 111 may include vacancy defects. The number of vacancy defects can be measured by the number of vacancy defects generated per unit volume of material. As long as the number of vacancy defects increases exponentially with increasing temperature, it can be calculated using the following formula 1.

[0131] Formula 1

[0132] Nv=Nexp(-Qv / kT)

[0133] Where Nv is the number of vacancy defects, N is the total number of potential defect sites, Qv is the activation energy, T is the temperature (in Kalvin scale), and k is Boltzmann's constant.

[0134] Furthermore, the structure of the region adjacent to the exhaust portion 190 may have a morphology of a plurality of grains 200. The plurality of grains 200 may be confirmed by observing the facing surface 111 with a scanning electron microscope (SEM).

[0135] The microstructure of the region adjacent to the vent 190 may include an equiaxed microstructure. That is, the grains 200 may have no orientation and have similar lengths along the three axes. The grains 200 may also be isotropic. This is because the grains 200 grow side by side along the three axes after the opposing surface 111 is heated.

[0136] At least a portion of any one of the plurality of dies 200 may be cut. This is because the vent 190 is formed by laser etching the opposing surface 111. That is, by laser etching the opposing surface 111, the vent 190 can be formed while minimizing thermal damage to the opposing surface 111.

[0137] The standard deviation of the sizes of the plurality of crystal grains 200 may be equal to or smaller than 20. That is, the sizes of the plurality of crystal grains 200 included in the overlapping portion may be uniform.

[0138] This is because the grain 200 is not subjected to external pressure after being heated to grow. Laser etching can cut the grain 200 by irradiating the grain 200 with laser light to form the vent 190, while the size of the grain 200 located inside the opposite surface 111 will not change.

[0139] The ten-point average roughness (Rz) of the surface of the vent portion 190 may be higher than the ten-point average roughness (Rz) of the area adjacent to the vent portion 190. Surface roughness can be classified based on a roughness curve analysis method, including maximum height roughness (Rmax, Ry), centerline average roughness (Ra), and ten-point average roughness (Rz).

[0140] The maximum height roughness (Rmax, Ry) is the distance between parallel lines drawn above and below the centerline of the surface roughness curve, expressed in μm. The maximum height roughness (Rmax, Ry) can be expressed in μm as the height difference between the highest and lowest points of the reference length of the surface roughness curve. The maximum height roughness (Rmax, Ry) can be defined as the average of the maximum heights for each reference length within the evaluation length.

[0141] The centerline average roughness (Ra) can be calculated by assuming the sum of the peak areas above the centerline of the surface roughness curve is S1, and the sum of the areas below the centerline is S2. The line that satisfies S1 = S2 is the centerline. The centerline average roughness (Ra) represents the arithmetic mean of the deviations along the measurement length.

[0142] The ten-point average roughness (Rz) may be the distance between two straight lines parallel to the center line passing through the third highest peak among the highest points and the third lowest valley among the lowest points in the cross-sectional curve within the reference length of the sampling portion.

[0143] Alternatively, the ten-point average roughness (Rz) can be calculated by taking the average height of the five highest peaks and the average depth of the five lowest valleys in a cross-sectional curve representing surface elevation. The ten-point average roughness (Rz) can be measured vertically in the roughness curve. The ten-point average roughness (Rz) can be the sum of the average of the first five absolute values ​​at the highest position and the average of the first five absolute values ​​at the lowest position in the roughness curve. The ten-point average roughness (Rz) can be expressed in micrometers (μm).

[0144] The ten-point average roughness (Rz) is a numerical value that quantitatively represents the surface roughness. The roughness of the surface of the vent portion 190 and the surface of the region adjacent to the vent portion 190 can be measured using a known roughness measurement method.

[0145] Specifically, roughness can be measured by sensory means, stylus method, optical interferometry or atomic force microscopy. Figure 7 In the embodiment, a resolidified layer 25 is formed on the surface of the vent portion 190 , and a relatively horizontal surface may be formed between the inclined surfaces. The ten-point average roughness (Rz) can measure the roughness of the horizontal surface of the vent portion 190 .

[0146] Because the width of vent 190 is limited, roughness can be measured using optical interferometry using a microscope or other method. The microscope can measure random locations on vent 190, with magnification settings ranging from 12x to 200x. The microscope can measure a length of 2 mm to 3 mm within vent 190. The ten-point average roughness (Rz) of the surface of vent 190 can be measured along the length of vent 190 in an image obtained through the microscope. The measured ten-point average roughness (Rz) of the surface of vent 190 can be higher than the surface roughness of areas adjacent to vent 190. In other words, the surface of vent 190 can be rougher than the surface of areas adjacent to vent 190.

[0147] This is because vent 190 is formed using a laser. If vent 190 were formed using a stamping method rather than a laser, the pressed surface would likely be flat. However, in the present disclosure, vent 190 is formed using a laser, resulting in a roughened surface. Specifically, the ten-point average roughness (Rz) of the surface of vent 190 can exceed 20.

[0148] In the present disclosure, the exhaust portion 190 is formed by laser, so that the exhaust portion 190 can be processed without the laser physically contacting the opposite surface 111 .

[0149] If vent 190 is formed by stamping, a die is inserted into housing 110, and then a punch is used to stamp the exterior of housing 110. Physical contact between the exterior of housing 110 and the punch may occur, potentially causing scratches or damage to the coating on housing 110. Furthermore, the stamping process may introduce foreign matter or cause physical deformation, such as distortion.

[0150] In the present disclosure, the exhaust portion 190 is formed by laser, thereby preventing contamination and damage to the housing 110 due to contact.

[0151] Figure 8 It is used to explain the method of manufacturing the battery cell according to the embodiment.

[0152] The electrode assembly 160 may include a first electrode 171, a separator, and a second electrode. The cell housing 110 may include an opening 114 formed on one side and an opposite side 111 facing the opening 114. The electrode assembly 160 may be accommodated within the housing 110 through the cell opening 114.

[0153] The method for manufacturing a battery cell may include a step ( S100 ) of processing the opposing surface 111 to form the vent portion 190 . The step of manufacturing the housing 110 may be performed before the step of forming the vent portion 190 .

[0154] The step S100 of forming the exhaust portion 190 may include forming a starting groove of the exhaust portion 190 by laser (not shown); and etching the opposite surface 111 by laser from the starting groove to form the exhaust portion 190 into a ring shape (not shown).

[0155] In the step of forming the starting groove of the exhaust portion 190, a portion of the exhaust portion 190 may be etched by laser to form the starting groove. The starting groove may be a starting point for forming the annular exhaust portion 190. The point where the laser starts etching the opposing surface 111 may be the starting groove.

[0156] In the step of etching the opposing surface 111, the opposing surface 111 may be continuously etched by laser from the starting groove to form a ring-shaped exhaust portion 190. Although the exhaust portion 190 is formed in a ring shape, it is not limited thereto and the exhaust portion 190 may be formed in a continuous polygonal shape.

[0157] After step S100 of forming the vent 190, the method for manufacturing a battery cell according to the present disclosure may perform step S300 of inserting the electrode assembly 160 into the housing 110. Furthermore, before step S300 of inserting the electrode assembly 160 into the housing 110, the method for manufacturing a battery cell according to the present disclosure may perform steps (not shown) of combining the first collector plate 141 with the first electrode 171 and combining the second collector plate 142 with the second electrode.

[0158] In the step of combining the collector plate 140 with the electrode, the electrode assembly 160 may be combined with the collector plate 140. The electrodes and the collector plate 140 are electrically connected by combining the first electrode 171 with the first collector plate 141 and combining the second electrode with the second collector plate 142.

[0159] Then, in step S300 of inserting the electrode assembly 160 into the housing 110, the electrode assembly 160 can be inserted into the housing 110 through the opening 114 so that the first collector plate 141 faces the opposing surface 111. The first collector plate 141 can be inserted into the housing 110 before the second collector plate 142. Thereafter, the step of electrically connecting the electrode terminal 130 passing through the opposing surface 111 to the first collector plate 141 can be performed.

[0160] After inserting the electrode assembly 160 into the case 110 in step S300 , the method for manufacturing a battery cell according to the present disclosure may further include coupling the cap plate 120 to the case 110 to close the opening 114 in step S500 .

[0161] By combining the housing 110 and the cover plate 120 , the interior of the housing 110 can be isolated from the outside.

[0162] The above description is merely an example of applying the principles of the present disclosure, and other configurations may be included without departing from the scope of the present invention.

Claims

1. A battery cell comprising: a housing including an opening formed on one side and an opposite side facing the opening, wherein the electrode assembly is accommodated in the housing through the opening; a cover plate coupled to the housing to close the opening; as well as The exhaust portion is formed in a groove shape on the opposite surface. The ten-point average roughness of the surface of the vent portion is higher than the ten-point average roughness of a region adjacent to the vent portion.

2. The battery cell according to claim 1, wherein: The exhaust portion is formed in a ring shape on a surface facing the outside of the housing among both side surfaces of the opposing surfaces.

3. The battery cell according to claim 1 or 2, further comprising: The first current collecting plate is disposed inside the housing between the opposing surface and the electrode assembly and is electrically connected to the electrode assembly.

4. The battery cell according to claim 3, further comprising: The electrode terminal is electrically connected to the first current collecting plate and is exposed to the outside through the opposite surface.

5. The battery cell according to claim 1, wherein: The shape of the exhaust portion is deformed according to the internal pressure of the housing.

6. The battery cell according to claim 1 or 5, wherein: When the internal pressure of the housing increases, at least a portion of the exhaust portion opens.

7. The battery cell according to claim 1, wherein: The thickness of the groove is 1 / 6 or less of the thickness of the opposing surface.

8. The battery cell according to claim 1 or 7, wherein: The structure of the region adjacent to the exhaust portion has a morphology of multiple grains. The structure of the region adjacent to the exhaust portion includes an equiaxed structure, or the plurality of crystal grains have isotropy.

9. The battery cell according to claim 8, wherein: At least a portion of any one of the plurality of dies is cut.

10. The battery cell according to claim 1, wherein: The exhaust portion is formed by laser and includes a resolidified layer formed by solidifying a partial region after being heated.

11. The battery cell according to claim 1 or 10, wherein: The ten-point average roughness of the exhaust portion surface exceeds 20.

12. A method for manufacturing a battery cell, the battery cell comprising a housing, the housing comprising an opening formed on one side and an opposite side facing the opening, and an electrode assembly comprising a first electrode, a separator, and a second electrode housed within the housing, the method comprising: The step of machining the opposing surfaces to form a vent.

13. The method for manufacturing a battery cell according to claim 12, wherein: The steps of forming the exhaust portion include: A step of forming a starting groove of the exhaust portion by laser; and The step of etching the opposing surfaces from the starting groove by laser to form the exhaust portion into a ring shape.

14. The method for manufacturing a battery cell according to claim 12, wherein: After the step of forming the exhaust portion, the method further comprises: a step of combining a first current collecting plate with the first electrode and combining a second current collecting plate with the second electrode; and The electrode assembly is inserted into the case through the opening portion so that the first current collecting plate faces the opposing surface.

15. The method for manufacturing a battery cell according to any one of claims 12 to 14, wherein: After the step of inserting the electrode assembly into the case, the method further includes coupling a cover plate to the case to close the opening.

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