Battery cell, battery pack comprising battery cell, and vehicle

Abstract

A battery cell according to one embodiment of the present application includes: an electrode assembly in which a first electrode, a second electrode, and a separator interposed between the first and second electrodes are wound around a winding axis; a can configured to accommodate the electrode assembly through an open end portion formed on one side; a lead wire covering the open end portion and having a pouring inlet formed therein; and a plug configured to seal the pouring inlet, wherein the plug includes an insertion portion configured to be inserted into the pouring inlet and a lead wire coupling portion extending upward from the insertion portion in the direction of the winding axis and seated on the lead wire, and a diameter of the insertion portion can be greater than an inner diameter of the pouring inlet.

Description

Technical Field

[0001] This disclosure relates to a battery cell, a battery pack including the battery cell, and a vehicle.

[0002] This application is based on and claims priority to Korean Patent Application No. 10-2024-0101084, filed with the Korean Intellectual Property Office on July 30, 2024, the entire disclosure of which is incorporated herein by reference. Background Technology

[0003] Cylindrical battery cells are structures that house coiled electrode assemblies within a cylindrical metal can, and are more robust to shock and temperature changes compared to pouch cells. Therefore, there is a growing demand for can-type batteries as battery cells for vehicle battery packs.

[0004] A method for manufacturing battery cells using a cylindrical can involves deep-drawing a sheet of metal to mold a circular bottom and a circular tubular sidewall portion attached thereto, in which an electrode assembly is housed, and then covering the open ends of the sidewall portion with a cap to complete the process.

[0005] The method of covering the open end of the battery can with a cap and securing the cap and battery can can be applied by crimping or seam welding.

[0006] Figure 1 This is a view showing a method of securing the cap and battery can using a conventional crimping method.

[0007] Reference Figure 1 Crimping is a method of securing the cap 40' by physically compressing the edge of the cap 40' to the open end of the can 10', wherein a sealing ring 91 is inserted between the edge of the cap 40' and the open end of the can 10'. Since crimping is a physical fixing method without applying heat, it allows the can 10' to function while the electrolyte is being injected into it. Therefore, the crimping method has the advantage of being able to omit a separate injection port structure and the structure used to seal that injection port. However, compared to welding, crimping is structurally more complex and therefore has limitations in terms of securing the internal volume of the can 10' capable of accommodating the electrode assembly 20'.

[0008] Conversely, seam welding is a method of welding the circumference of the front end of the side wall of the battery can to the circumference of the edge of the cover along the circumferential direction. Because of its simple fixing structure, it further ensures the volume of the electrode assembly that can be accommodated within the battery can. Therefore, compared to a battery can of the same volume, the seam welding method is more advantageous in fixing capacitors.

[0009] For example, a sealing member such as a metal ball can be forcibly press-fitted into the injection port to seal and secure it. This method involves a metal ball having a diameter larger than the inner circumferential surface of the injection port being forcibly press-fitted into the port, and the elastic deformation of the inner circumferential surface of the injection port and the metal ball causing their surfaces to compress against each other, resulting in a seal.

[0010] Traditionally, aluminum balls have been used as metal spheres to seal the injection port. Aluminum balls can be fired at low temperatures, and therefore, when pressed with an aluminum ball slightly larger than the injection port, the aluminum can deform to seal the port. However, aluminum balls cannot be used when the cap forming the injection port is itself the negative electrode of the battery.

[0011] On the other hand, if steel balls are used instead of aluminum, a seal should be achieved between the rigid cap and the rigid ball. However, during the process of forcibly press-fitting the steel ball into the cap's inlet, scratches parallel to the press-fit direction appear on the inner circumferential surface of the inlet and the surface of the steel ball. These scratches cause problems by acting as channels through which gas leaks from the battery cell.

[0012] However, if the steel ball is pressed in with very strong force to eliminate these channels, the cap itself deforms in the press-fit direction, which not only causes appearance defects in the cap, but also causes short circuits due to contact between the deformed cap and the electrode assembly inside the can.

[0013] Alternatively, blind riveting can be used to physically seal the injection port. This method also requires a seal between the rigid rivet and the rigid cap, but scratches may occur during the riveting process, leading to the same problems as described above.

[0014] Therefore, coating the surface of the steel ball with polymer materials (rubber, plastic) that have high chemical resistance and mechanical rigidity could be considered. However, such materials are expensive, and there is a risk that the polymer materials may deteriorate due to repeated temperature shocks from alternating high and low temperatures, which could also lead to gas leakage.

[0015] Meanwhile, to reduce the possibility of gas leakage between the rigid cap and the rigid inlet cap, a method could be considered of covering the inlet with a steel cap and then welding the gap between the cap and the inlet to seal it. However, even with this method, the heat generated when welding the cap to the cap can cause the gas from the electrolyte evaporation inside the tank to be released. Therefore, there is a risk of cracks or gas passages forming at the cap connection along the gas release path, and a risk of electrolyte leakage or fire due to high temperature, heat, gas, and oxygen.

[0016] Therefore, there is a need for a sealing structure for the injection port with improved sealing performance, which eliminates electrolyte leakage, gas leakage due to electrolyte evaporation, and the risk of welding defects or fire. Summary of the Invention

[0017] Technical issues

[0018] The present invention was designed in consideration of the above-mentioned problems. Therefore, the present invention aims to provide a sealing structure and sealing method for an injection port that will not pose a risk of welding defects or fire due to electrolyte gas, even when welding is performed to seal the injection port.

[0019] In addition, the present invention aims to provide a battery cell including such a sealed structure.

[0020] In addition, this disclosure relates to a method for manufacturing battery cells using this sealing method.

[0021] In addition, this disclosure relates to providing a battery cell with high energy density by eliminating the beading and crimping structures in the battery cell, and a vehicle equipped with a battery pack using the battery cell.

[0022] The technical problem addressed by this disclosure is not limited to the objectives described above, and other objectives and advantages of this disclosure not mentioned herein may be understood through the following description and will become clearer through embodiments of this disclosure. Furthermore, it will be readily understood that the objectives and advantages of this disclosure can be achieved by the means indicated in the claims and combinations thereof.

[0023] Technical solution

[0024] A battery cell according to an embodiment of the present disclosure for solving the above-mentioned problems may include: an electrode assembly formed by winding a first electrode, a second electrode, and a diaphragm inserted between the first electrode and the second electrode around a winding shaft; a can configured to receive the electrode assembly by means of an open end formed on one side; a cap covering the open end and forming an injection port; and a plug configured to seal the injection port, wherein the plug includes an insertion portion and a cap connecting portion, the insertion portion being configured to be inserted into the injection port, and the cap connecting portion extending upward from the insertion portion in the direction of the winding shaft and disposed on the cap, and the diameter of the insertion portion being larger than the inner diameter of the injection port.

[0025] The tolerance between the diameter of the insertion part and the inner diameter of the injection port can be from 50 μm to 150 μm.

[0026] The diameter of the cover connecting part can be larger than the diameter of the insertion part.

[0027] The diameter of the cap connection portion can be at least 1.1 to 1.5 times the diameter of the insertion portion.

[0028] The side surfaces of the insertion portion and the cover connection portion are spaced apart from each other in the horizontal direction.

[0029] The side surface of the insertion part can be an inclined surface tilted at a specified angle.

[0030] The diameter of the lower surface of the insertion part can be made smaller than the diameter of the upper surface of the insertion part, and the inner diameter of the injection port can be larger than the diameter of the lower surface of the insertion part and smaller than the diameter of the upper surface of the insertion part.

[0031] The cap may include a body portion and a plug connector portion, the plug connector portion being recessed downward relative to the body portion in the direction of the winding axis around the injection port and configured to allow placement of the cap connector portion.

[0032] The cap connection portion of the plug and the main body portion of the cap can be configured to face each other in the radial direction and be welded together.

[0033] The can and the lid can be heat-jointed.

[0034] A method for manufacturing a battery cell according to an embodiment of the present disclosure may include the following steps: covering an open end of a can with an electrode assembly housed in it; thermally bonding an edge of the cover to the can; injecting an electrolyte into the interior of the can through an inlet of the cover; sealing the inlet by inserting an insertion portion of a plug into the inlet; and welding the cover to a cover coupling portion formed to extend upward from the insertion portion of the plug in the direction of the winding shaft and disposed on the cover.

[0035] A battery pack according to an embodiment of the present disclosure for solving the above problems may include battery cells according to an embodiment of the present disclosure.

[0036] A vehicle according to an embodiment of the present disclosure for solving the above problems may include a battery pack according to an embodiment of the present disclosure.

[0037] Beneficial effects

[0038] According to one aspect of this disclosure, a sealing structure and sealing method for an injection port are provided, which do not pose a risk of welding defects or fire due to electrolyte gas, even when welding is applied to seal the injection port, and improve the reliability of the injection port seal.

[0039] According to one aspect of this disclosure, the injection port is configured to allow only one unit component, i.e., a plug, to be inserted therein, which can relatively expand the internal space of the cell and allow the injection port to be formed wider, thereby improving the liquid injection efficiency.

[0040] According to one aspect of this disclosure, a temporary sealing force can be obtained by press-fitting the insertion portion of the plug to prevent external leakage of electrolyte vapor, and a high final sealing force can be ensured by thermally joining a portion of the cap to the edge of the cap connection portion of the plug. Because thermal joining can be performed while preventing external leakage of electrolyte vapor, there is an effect of preventing welding defects and fire, for example, when thermal joining is performed using laser welding.

[0041] According to one aspect of this disclosure, the injection port can be sealed with a unit component using two processes: press fitting and heat bonding. Therefore, the number of components can be reduced, and assembly time can be decreased.

[0042] However, the effects obtained through this disclosure are not limited to those described above, and other effects not mentioned herein will be clearly understood by those skilled in the art based on the following description of this disclosure. Attached Figure Description

[0043] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, serve to provide a further understanding of the technical features of the present disclosure; therefore, the present disclosure is not to be construed as limited to the drawings.

[0044] Figure 1 This is a view showing a method of securing the cap and battery can using a conventional crimping method.

[0045] Figure 2 This is a perspective view of a battery cell according to an embodiment of the present disclosure.

[0046] Figure 3 This is a perspective view showing the state prior to the lamination of the first electrode, the second electrode, and the separator to manufacture the electrode assembly to be housed in a battery casing according to an embodiment of the present disclosure.

[0047] Figure 4 It is by... Figure 3 A perspective view of an electrode assembly manufactured by winding a laminate into a core shape.

[0048] Figure 5 and Figure 6 This is a perspective view showing the current collectors, according to an embodiment of the present disclosure, respectively bonded to both ends of the electrode assembly.

[0049] Figure 7This is a cross-sectional view illustrating the process of housing an electrode assembly according to an embodiment of the present disclosure in a battery can.

[0050] Figure 8 This is a cross-sectional view showing the state in which the container holding the electrode assembly according to an embodiment of the present disclosure is covered and sealed with a lid.

[0051] Figure 9 This is a cross-sectional view showing the state in which the injection port of the cap according to an embodiment of the present disclosure is sealed by a plug.

[0052] Figure 10 This is a cross-sectional view showing a plug according to an embodiment of the present disclosure.

[0053] Figure 11 This is a cross-sectional view showing the state in which the plug according to an embodiment of the present disclosure is inserted into the cap.

[0054] Figure 12 This is a cross-sectional view showing the state in which the plug and cap are connected according to an embodiment of the present disclosure.

[0055] Figure 13 This is a cross-sectional view showing the state in which the plug is inserted into the cap according to another embodiment of the present disclosure.

[0056] Figure 14 This is a cross-sectional view showing the state in which the plug and cap are connected according to another embodiment of the present disclosure.

[0057] Figure 15 This is a cross-sectional view showing the cap and plug being connected according to yet another embodiment of the present disclosure.

[0058] Figure 16 This is a cross-sectional view showing a plug according to yet another embodiment of the present disclosure.

[0059] Figure 17 This is a cross-sectional view showing the cap and plug being connected according to yet another embodiment of the present disclosure.

[0060] Figure 18 This is a flowchart of a method for manufacturing a battery cell, and the injection port sealing structure disclosed herein is applied to the battery cell.

[0061] Figure 19 This is a view depicting a battery pack according to an embodiment of the present disclosure.

[0062] Figure 20 It describes including Figure 19 A view of the vehicle with its battery pack. Detailed Implementation

[0063] In the following, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0064] This disclosure is not limited to the embodiments disclosed below, but can be modified and implemented in various ways and forms. These embodiments are provided merely to ensure the completeness of this disclosure and to fully inform those skilled in the art of its scope. Therefore, this disclosure is not limited to the embodiments disclosed below, but should be understood to include all modifications, equivalents, and substitutions within the technical concept and scope of this disclosure, as well as replacing or adding a configuration of one embodiment to the configuration of another.

[0065] Furthermore, this disclosure includes various embodiments. For each embodiment, redundant descriptions of substantially the same or similar configurations will be omitted, and the differences will be primarily described.

[0066] The accompanying drawings are intended only to aid in understanding the embodiments disclosed herein, and the technical concepts disclosed herein are not limited to the drawings. All modifications, equivalents, and substitutions within the scope of the ideas and techniques of this disclosure should be understood to be included herein. In the drawings, components may be exaggerated in size or thickness for ease of understanding, but this should not be construed as limiting the scope of protection of this disclosure.

[0067] The terminology used herein is for the purpose of describing a particular implementation or method of practice only and is not intended to limit this disclosure. Furthermore, singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as 'comprising' and 'including' are intended to specify the presence of features, quantities, steps, operations, components, portions, or combinations thereof described herein. That is, terms such as 'comprising' and 'including' in this specification should be understood as not precluding the presence or addition of one or more other features, numbers, steps, operations, components, portions, or combinations thereof.

[0068] Ordinal terms (such as first and second) can be used to describe various components, but these components are not limited by these terms. These terms are only used to distinguish one component from another. Therefore, unless otherwise stated, it is obvious that the first component can be the second component.

[0069] Throughout the instruction manual, unless explicitly stated otherwise, each part may be singular or plural.

[0070] Unless the context clearly indicates otherwise, singular expressions used herein include plural expressions. In this application, terms such as “comprise” or “include” should not be construed as necessarily including all the various components or steps described in the specification, but should be construed as excluding some components or steps, or further including additional components or steps.

[0071] When a component is described as being "connected" or "coupled" to another component, the components may be directly connected or coupled to each other, but it should be understood that other components may be present in between. On the other hand, when a component is described as being "directly connected" or "directly coupled" to another component, it should be understood that no other components are present in between.

[0072] When describing any component as "above" or "below" another component, it should be understood that the component is directly positioned above the other component, and furthermore, there may be other components between them.

[0073] Unless otherwise defined, all terms used herein (including technical or scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Terms as defined in commonly used dictionaries shall be interpreted as having a meaning consistent with their meaning in the context of the relevant art and shall not be interpreted as having an ideal or overly formal meaning unless expressly defined herein.

[0074] At the same time, terms indicating directions such as up, down, left, right, front, and back may be used in this disclosure, but these terms are only for the convenience of description, and it will be apparent to those skilled in the art that these terms may vary depending on the position, arrangement, rotation of the reference object, or the position of the observer.

[0075] Throughout the specification, when “A and / or B” is mentioned, it means A, B or both A and B, unless otherwise expressly stated to the contrary, and when “C to D” is mentioned, it means C or more and D or fewer, unless otherwise expressly stated to the contrary.

[0076] This disclosure can be implemented independently by each of the following embodiments. Furthermore, this disclosure can be implemented by combining two or more of the following embodiments. Each of the following embodiments can be implemented independently and can also be freely combined with each other.

[0077] For ease of description, in this specification, the direction along the length of the winding axis of the electrode assembly wound in the form of a core is referred to as the winding axis direction. Furthermore, the direction around the winding axis of the electrode assembly is referred to as the circumferential direction, and the direction in which the electrode assembly is wound along the winding axis is referred to as the winding direction. Additionally, the direction of movement away from or towards the winding axis of the electrode assembly is referred to as the radial direction.

[0078] Figure 2 This is a perspective view of a battery cell according to an embodiment of the present disclosure. Figure 3 This is a perspective view showing the state prior to the lamination of the first electrode, the second electrode, and the separator to manufacture the electrode assembly to be housed in a battery case according to an embodiment of the present disclosure. Figure 4 It is by... Figure 3A perspective view of an electrode assembly manufactured by winding a laminate into a core shape. Figure 5 and Figure 6 This is a perspective view showing the current collectors, according to an embodiment of the present disclosure, respectively bonded to both ends of the electrode assembly. Figure 7 This is a cross-sectional view illustrating the process of accommodating an electrode assembly according to an embodiment of the present disclosure in a battery can. Figure 8 This is a cross-sectional view showing the state in which the container holding the electrode assembly according to an embodiment of the present disclosure is covered and sealed with a lid.

[0079] In the following text, reference will be made to Figures 2 to 8 A detailed description is provided of an embodiment of the battery cell 1 that utilizes the injection port 42 sealing structure of this disclosure.

[0080] The battery cell 1 can be manufactured by embedding a cylindrical electrode assembly 20 inside a cylindrical battery canister 10.

[0081] The battery cell 1 in this embodiment may include an electrode assembly 20, current collectors 31 and 32 electrically connected to the electrode assembly 20, and a tank 10 for accommodating the electrode assembly 20 and the current collectors 31 and 32.

[0082] The can 10 may include a sidewall portion 11 and a bottom portion 12. The sidewall portion 11 extends between a first end and a second end in the winding axis direction, and the bottom portion 12 is connected to the first end of the sidewall portion 11 and extends in the radial direction. The second end of the sidewall portion 11 in the winding axis direction may be open.

[0083] After the electrode assembly 20 is housed in the canister 10, it can be sealed by covering the open end of the side wall portion 11 with the cap 40.

[0084] The bottom 12 may have a disc shape with a hole in the center, and the side wall portion 11 may have a tube shape.

[0085] The bottom 12 and the side wall 11 can be manufactured by deep drawing a nickel-plated metal sheet onto the surface of steel while the side wall 11 is held in a blank holder, and then finishing the front end of the side wall 11 with a punch. Of course, the material of the can 10 is not limited to this.

[0086] The first electrode terminal 13 can be fitted into the hole. The first electrode terminal 13 can be riveted and fixed to the bottom 12, and a terminal washer 14 is inserted between the first electrode terminal 13 and the bottom 12. The terminal washer 14 can be inserted between the first electrode terminal 13 and the bottom 12 to seal the inside and outside of the can 10, thereby preventing electrolyte leakage and electrically insulating the first electrode terminal 13 from the bottom 12.

[0087] However, the connection method between the first electrode terminal 13 and the bottom 12 is not limited to this. For example, various other fixing methods can be applied, such as bolt-nut connection, glass sealing, or chrome coating & PP-MAH thermal bonding, as long as the structure can provide a seal between the first electrode terminal 13 and the bottom 12 and electrically insulate the first electrode terminal 13 from the bottom 12.

[0088] The first electrode terminal 13 may have a first polarity, and the can 10 may have a second polarity. That is, the bottom 12 of the can 10, the side wall portion 11 connected to the bottom 12, and the cover 40 (described later) connected to the side wall portion 11 may all have a second polarity.

[0089] Therefore, the battery cell 1 may have a first electrode terminal 13 and a second electrode terminal 15 both disposed at the ends in the winding axis direction (i.e., the closed ends where the bottom 12 is disposed). Then, the battery cell 1 may have a busbar connected to the first electrode terminal 13 and a busbar connected to the second electrode terminal 15, both of which are located at the top of the battery cell 1.

[0090] In one example, the first electrode terminal 13 can be the positive terminal, and the second electrode terminal 15 can be the negative terminal. Of course, the reverse is also possible.

[0091] Electrode assembly 20 is housed within tank 10.

[0092] The electrode assembly 20 may be in the form of a core in which the first electrode 21, the second electrode 22, and the diaphragm 28 inserted therebetween are wound around a winding shaft. The external shape of the electrode assembly 20 along its circumferential direction may be circular. However, the structure of the electrode assembly 20 is not limited to any particular embodiment and may have a winding structure known in the art.

[0093] Specifically, a first electrode 21, a second electrode 22, and a diaphragm 28 extending to a predetermined length along a winding direction having a predetermined width are prepared, and a laminate is formed by sequentially laminating the first electrode 21, the diaphragm 28, the second electrode 22, and the diaphragm 28 (e.g., ...). Figure 3 (as shown), then as Figure 4 As shown, by winding the laminate around a mandrel, the electrode assembly 20 can be manufactured into a cylindrical form of a wound core. The structure of the electrode assembly 20 is not limited to any particular embodiment and can have a winding structure known in the art.

[0094] The first electrode 21 can be the positive electrode, while the second electrode 22 can be the negative electrode. Of course, the reverse is also possible.

[0095] The first electrode 21 and the second electrode 22 are manufactured in the form of sheets. The electrode sheets are manufactured in the form of an active material layer 24 applied to the surface of the metal foil 23. The electrode sheets have a coated portion 25 on which the active material layer 24 is applied and an uncoated portion 26 on which the active material layer 24 is not applied. The positive electrode sheet has an uncoated portion 26 on one side of its width direction, and the negative electrode sheet has an uncoated portion 26 on the other side of its width direction.

[0096] The uncoated portion 26 is exposed or protrudes from the laminate in the width direction. The uncoated portion 26 itself functions as an electrode sheet.

[0097] The uncoated portion 26 can be cut at predetermined intervals to form a flag-shaped die-cut tab 27.

[0098] In this embodiment, the die-cut tabs 27 illustrated have an isosceles trapezoidal shape. However, their shape can be various, such as semicircle, semi-ellipse, triangle, rectangle, parallelogram, etc.

[0099] Furthermore, this embodiment shows that the die-cut tabs 27 arranged along the length direction have the same width. However, the width of the die-cut tabs can gradually or progressively increase from the mandrel side to the outer periphery side.

[0100] Furthermore, this embodiment shows that the height of the die-cut tabs 27 gradually increases from the mandrel side to the outer periphery side. However, the height of these die-cut tabs can be implemented in a constant form or in a gradually decreasing form.

[0101] Furthermore, this embodiment shows a structure in which the die-cut tabs 27 are removed from a predetermined portion at the centrifugal end and a predetermined portion at the radial end of the uncoated portion 26. However, it is apparent that the die-cut tabs may not be removed at the centrifugal end of the uncoated portion, nor may they be removed at the radial end of the uncoated portion.

[0102] In the wound electrode assembly 20, the die-cut tabs 27 can be radially bent and flattened, such as Figure 4 As shown, the die-cut tab 27 can be bent radially inward or outward. This embodiment illustrates a structure in which the die-cut tab 27 is bent radially inward.

[0103] During the process of forming the wound electrode assembly 20 by winding the laminate, the die-cut tabs 27 can be bent one after another. Alternatively, the die-cut tabs 27 can be bent all at once immediately after the laminate is wound to form the wound electrode assembly.

[0104] The die-cut tabs 27 of the first electrode 21 and the second electrode 22, which are radially bent and overlapped in this manner, can each provide a plane substantially perpendicular to the winding axis direction at both ends of the electrode assembly 20.

[0105] like Figure 5 and Figure 6 As shown, the first current collector 31 and the second current collector 32 can each be coupled to a substantially flat surface provided by the die-cut tabs 27 exposed at both ends in the winding axis direction of the electrode assembly 20.

[0106] This embodiment shows that the first current collector 31 is a positive current collector, and the second current collector 32 is a negative current collector. The first current collector 31 may be made of aluminum, and the second current collector 32 may be made of copper.

[0107] The current collectors 31 and 32 can be manufactured by stamping, trimming, perforating and bending metal sheets.

[0108] Reference Figure 5 The first current collector 31 may include a first terminal connection portion 312 extending radially from the center, an annular portion 313 connecting the centrifugal edge of the first terminal connection portion 312 in the circumferential direction, and a first electrode connection portion 314 extending concentrically from the annular portion 313 and not connected to the first terminal connection portion 312. The center of the first terminal connection portion 312 may cover at least a portion of the winding center hole H of the electrode assembly 20.

[0109] Before placing the electrode assembly 20 into the tank 10, the first electrode connection portion 314 is joined to the die-cut tab 27 of the first electrode 21 of the electrode assembly 20 by means of laser welding or the like. The welding line of the laser can extend radially.

[0110] Reference Figure 6 The second current collector 32 may include: an inner ring portion 321 defining a hole 322 corresponding to the winding center hole H of the electrode assembly 20 and disposed around the winding center hole H; a second electrode connection portion 323 extending radially from the inner ring portion 321; and a second terminal connection portion 324 disposed on a side further away from the center of the winding core than the second electrode connection portion 323 and connected to the inner ring portion 321. The second terminal connection portion 324 may have the form of an outer ring surrounding the edge of the second current collector 32.

[0111] Before placing the electrode assembly 20 into the tank 10, the second electrode connection 323 can be joined to the die-cut tab 27 of the second electrode 22 of the electrode assembly 20 by means of laser welding or the like. The welding line of the laser can extend radially.

[0112] However, the shape and structure of the first current collector 31 and the second current collector 32 are not limited to the embodiments described above, and can be designed and modified in various ways. It is also possible to omit the structure of the second current collector 32. In this case, the cover 40, described later, will be used as the second current collector.

[0113] like Figure 7 As shown, the electrode assembly 20 can be housed in the can 10 with the first current collector 31 aligned with the bottom 12 of the can 10. At this time, the insulator 19 can be inserted between the first current collector 31 and the bottom 12 of the can 10 to electrically insulate the first current collector 31 from the bottom 12.

[0114] With the electrode assembly 20 housed within the canister 10, the die-cut tabs 27 of the second electrode 22 and the second current collector 32 can be configured as open ends facing the sidewall portion 11.

[0115] The first terminal connection portion 312 of the first current collector plate 31 can be joined to the first electrode terminal 13 fixed to the can 10 by resistance welding, ultrasonic welding, laser welding, etc. A welding device for welding the first current collector plate 31 and the first electrode terminal 13 can pass through the open portion of the can 10, the hole 322 of the second current collector plate 32, and the winding center hole H of the electrode assembly 20 to approach the rear surface of the center of the first terminal connection portion 312 of the first current collector plate 31 to perform welding. Of course, in addition to this, the first current collector plate 31 and the first electrode terminal 13 can also be joined by copper soldering, tin soldering, etc. That is, the first current collector plate 31 and the first electrode terminal 13 can be connected to each other in various ways, as long as they can be electrically connected and fixed to each other. However, this disclosure does not exclude a structure in which the positive electrode tab is directly electrically connected to the positive terminal in the state of omitting the positive current collector plate.

[0116] With the electrode assembly 20 housed in the container 10, the open end of the container 10 can be sealed by covering it with the lid 40, such as Figure 8 As shown.

[0117] The can 10 and the cover 40 can be thermally joined. The circumference of the front end of the side wall portion 11 of the battery can 10 and the circumference of the edge of the cover 40 can be welded together in the circumferential direction. The contact point between the open end of the can 10 and the cover 40 can be connected together. For example, the connection point between the open end of the can 10 and the cover 40 can be connected by welding. For example, the cover 40 can be connected to the can 10 by butt welding. This can be defined as a seam welding method. Due to the simplicity of the fixing structure, the volume of the electrode assembly 20 that can be accommodated within the can 10 can be further guaranteed. Therefore, compared with the same volume of the can 10, the seam welding method may be more advantageous in ensuring the capacitance.

[0118] Specifically, when the open end of the tank 10 and the perimeter of the cover 40 are fixed by seam welding, the following method can be applied: prepare a cover 40 with an injection port 42, house the electrode assembly 20 inside the tank 10, inject electrolyte through the injection port 42 provided at the cover 40 after seam welding the tank 10 and the cover 40, and seal the injection port 42 with a plug 50 or the like after the injection is completed.

[0119] According to this structure, by omitting the crimping and pressing structures in the battery cell 1, various process errors that may be caused by the crimping and pressing structures can be prevented. Furthermore, process simplification can be achieved by omitting the crimping and pressing processes. In addition, the formation of the crimping and pressing structures can prevent the dead zone within the battery from increasing in the winding axis direction of the electrode assembly 20 and thus reducing energy density. Therefore, compared to battery cells using crimping and pressing methods, the battery cell 1 according to this disclosure can increase internal capacity within the same external shape. That is, according to the structure in this disclosure, the energy density of the battery cell 1 can be improved.

[0120] The second terminal connection portion 324 of the second current collector 32 and the second end of the side wall portion 11 can be joined by a method such as welding. The edges of the can 10 and the lid 40 can be sealed by a method such as welding. In one example, after the second current collector 32 and the can 10 are joined, the lid 40 and the can 10 can be joined. In another example, after the second current collector 32 and the lid 40 are joined, the lid 40 and the can 10 can be joined. In yet another example, the second current collector 32, the can 10, and the lid 40 can be welded simultaneously.

[0121] The edge of the cover 40 can be electrically connected by engaging with the edge of the open end of the can 10. The inner surface of the cover 40 or the can 10 can be electrically connected to the second current collector 32. The second current collector 32 engages with the die-cut tab 27 of the second electrode 22 of the electrode assembly 20 housed within the can 10 of the battery cell 1, and therefore, when the cover 40 is electrically connected to the second current collector 32, the cover 40 can also be electrically connected to the die-cut tab 27 of the second electrode 22 of the electrode assembly 20. However, in a structure that omits the second current collector 32, the shape of the cover 40 can be changed so that the cover 40 can be directly electrically connected to the die-cut tab 27 of the second electrode 22 of the electrode assembly 20. That is, the cover 40 according to this disclosure can be configured as a so-called integrated cover 40 capable of simultaneously performing the function of a current collector. Therefore, the internal capacity of the same external shape can be increased compared to a battery cell 1 with a current collector interposed therebetween. Therefore, the energy density of the battery cell 1 can be increased.

[0122] After sealing the container 10 with the lid 40, the electrolyte can be injected into the container 10 through the injection port 42 provided in the lid 40.

[0123] The cover 40 can be made of a metallic material. Therefore, the cover 40 can be conductive. For example, the cover 40 may comprise aluminum. The cover 40 can be made of, for example, low-carbon steel. The cover 40 can be made of, for example, nickel-plated steel (Ni-plated steel), cold-rolled steel (SPCC or SPCE), or stainless steel (SUS). The cover 40 can be manufactured, for example, by molding a sheet metal using a press. The cover 40 can be formed to have a thickness of, for example, 0.1 mm to 2.0 mm. The cover 40 can be formed to have a thickness of, for example, 0.3 mm to 1.0 mm.

[0124] Figure 9 This is a cross-sectional view showing the state in which the injection port of the cap according to an embodiment of the present disclosure is sealed by a plug. Figure 10 This is a cross-sectional view showing a plug according to an embodiment of the present disclosure. Figure 11 This is a cross-sectional view showing the state in which the plug according to an embodiment of the present disclosure is inserted into the cap. Figure 12 This is a cross-sectional view showing the state in which the plug and cap are connected according to an embodiment of the present disclosure.

[0125] Reference Figures 9 to 12 According to this disclosure, the battery cell 1 may include an electrode assembly 20, a can 10, a cap 40 having an injection port 42, and a plug 50.

[0126] An injection port 42 may be formed in at least a portion of the cover 40. The injection port 42 may be formed at the center of the cover 40. In this case, the injection port 42 may be blocked by a plug 50. For example, the plug 50 may be press-fitted into the injection port 42. By blocking the injection port 42 with the plug 50, the airtightness of the battery cell 1 can be ensured.

[0127] Inlet 42 can be used, for example, as an electrolyte injection port. The center of inlet 42 can coincide with the center of the winding center hole H of the electrode assembly 20. That is, the injection port 42 of the cover 40 can be positioned above the winding center hole H of the electrode assembly 20 in the winding axis direction.

[0128] Reference Figure 9 and Figure 10 The stopper 50 can be configured to seal the injection port 42. That is, the stopper 50 can be configured to be inserted into the injection port 42. At least a portion of the stopper 50 can pass through the injection port 42. By inserting the stopper 50 into the injection port 42 of the cap 40, the airtightness of the battery cell 1 can be ensured. The stopper 50 can pass through the injection port 42 formed in the cap 40 and is thermally bonded (welded) to the cap 40. Therefore, the exterior and interior of the can 10 can be sealed, and leakage of electrolyte can be prevented.

[0129] According to this structure, the crimping and pressing processes can be omitted, thereby simplifying the manufacturing process. Furthermore, it prevents the dead zone within the battery from increasing in the winding axis direction of the electrode assembly 20 due to the crimping and pressing structure, thus preventing a decrease in energy density. In other words, according to the structure disclosed herein, the energy density of the battery cell 1 can be improved.

[0130] The plug 50 can be configured to cover the injection port 42. The plug 50 can refer to, for example, a sealing member covering the injection port 42, a plug, etc. The plug 50 can include at least one of low-carbon steel and copper (Cu).

[0131] At least a portion of the plug 50 can be press-fitted into the injection port 42. For example, the press-fit load of the plug 50 can be approximately 150 kgf or less.

[0132] The plug 50 may include an insertion portion 51 and a cap connecting portion 52. The insertion portion 51 and the cap connecting portion 52 may be in the shape of pillars with different diameters. The plug 50 may have a step in the radial direction.

[0133] The insertion part 51 can be configured to be inserted into the injection port 42.

[0134] Reference Figure 10 and Figure 11 The diameter D1 of the insertion portion 51 can be larger than the inner diameter R1 of the injection port 42 (D1>R1). For example, the overlap dimension or tolerance (t) between the diameter D1 of the insertion portion 51 and the inner diameter R1 of the injection port 42 can be from 20 μm to 300 μm. For example, the overlap dimension or tolerance (t) between the diameter D1 of the insertion portion 51 and the inner diameter R1 of the injection port 42 can be from 50 μm to 150 μm. For example, the tolerance (t) between the plug 50 and the injection port 42 can be approximately 70 μm to 150 μm in the radial direction. Here, the overlap dimension or tolerance (t) between the diameter D1 of the insertion portion 51 and the inner diameter R1 of the injection port 42 can refer to the distance between the outer surface of the insertion portion 51 formed on one side centered on the injection port 42 and the inner surface of the cap 40. That is, the insertion portion 51 can be forcibly fitted into the injection port 42.

[0135] According to an embodiment of the present disclosure, the diameter D1 of the insertion portion 51 of the plug 50 is formed to be larger than the inner diameter R1 of the injection port 42, so that the insertion portion 51 can be forcibly inserted into the injection port 42 by physical force, and the electrolyte formed therein can be prevented from flowing out of the injection port 42.

[0136] Furthermore, according to the above-described embodiment of this disclosure, by press-fitting the insertion portion 51 of the plug 50 into the injection port 42 before the heat-bonding cap 40 and the cap connection portion 52, a temporary sealing force can be obtained first. This temporary sealing force is sufficient to obtain a sealing force that resists the pressure of the vaporized gas of the electrolyte caused by the welding heat generated during heat bonding. Therefore, the deterioration of the welding quality due to the evaporation of the electrolyte can be prevented. For example, the temporary sealing force obtained by press-fitting the plug 50 can be based on 10% of the He leakage. -5 Up to 10 -3 atm·cc / s. Here, He leak testing can refer to a test that quantitatively assesses the presence of micro-leakage in a target component by using helium (He) as a tracer gas for leak detection. Since this temporary seal is sufficient to suppress vapor emission, the risk of welding defects and electrolyte ignition during subsequent welding processes can be prevented. In other words, high airtightness can be ensured.

[0137] Specifically, the welding heat generated during the joining of the cap 40 and the cap joint 52 using a thermal bonding method such as laser welding can increase the partial pressure of flammable electrolyte vapor, which has a relatively low boiling point of about 90°C, thereby causing the vapor to be released to the outside. If the released vapor comes into contact with the hot plug 50 or cap 40, it may increase the risk of fire or explosion, or welding defects (e.g., porosity, incomplete bonding) may occur.

[0138] However, according to this disclosure, by using a forced press-fit method to seal the plug 50, vapor leakage is prevented, thereby preventing contact between vapor and the high-temperature molten plug 50 or cap 40 during welding. Therefore, the stability and reliability of the laser welding process can be improved, and deterioration of weld quality or fire accidents can be prevented.

[0139] Furthermore, according to the above embodiments of this disclosure, the temporary sealing force is lower than the final sealing force. Therefore, compared to the case where the sealing force is ensured solely by press-fitting, the press-fitting load on the plug 50 can be reduced. Thus, localized plastic deformation or structural damage that may occur in the cap 40 or can 10 due to excessive press-fitting force can be effectively prevented.

[0140] The cover connecting portion 52 may be formed to extend upward from the insertion portion 51 along the winding axis direction. The cover connecting portion 52 may be mounted on the cover 40.

[0141] The diameter D2 of the cover connecting portion 52 can be larger than the diameter D1 of the insertion portion 51 (D2>D1). For example, the diameter D2 of the cover connecting portion 52 can be at least about 1.1 to 1.5 times larger than the diameter D1 of the insertion portion 51. For example, the diameter D2 of the cover connecting portion 52 can be about 1.2 times larger than the diameter D1 of the insertion portion 51.

[0142] The side surfaces of the insertion portion 51 and the cover connecting portion 52 may be spaced apart from each other in the horizontal direction. The edge portions of the cover connecting portion 52 and the edge portions of the insertion portion 51 may be spaced apart from each other in the horizontal direction.

[0143] See Figure 10 The lower edge of the cover connection portion 52 can be rounded (r). When in contact with the cover 40, this rounding (r) minimizes any steps or disturbances, thereby achieving a precise and stable connection without overlapping with the cover 40. This not only improves the ease of assembly but also reduces mechanical stress concentration. Furthermore, the shape of the cover connection portion 52 is not limited to the above embodiment and can be designed and modified in various ways. Additionally, other corner portions can also be rounded (r) in the same manner. This further improves the overall assemblability and durability of the component.

[0144] Typically, when the relative distance between the insertion portion 51 and the cap connection portion 52 is close, electrolyte vapor or residual vapor generated after electrolyte injection can be re-vaporized by heat during the welding process and flow into the welding area of ​​the cap connection portion 52. This vapor mixing may lead to reduced weld strength, the formation of pores, or the risk of fire during laser welding.

[0145] According to the embodiments described above in this disclosure, by designing the insertion portion 51 and the cover connecting portion 52 to be spaced apart from each other by a certain distance or more, a structure can be provided that makes it difficult for electrolyte vapor to reach the welding area. Therefore, welding defects can be prevented, and the risk of fire due to electrolyte leakage can be prevented.

[0146] The cap 40 and the plug 50 can be thermally joined at the cap connection 52. The thermal joining of the cap 40 and the cap connection 52 can be performed by welding, brazing, or soldering. That is, the edge of the cap connection 52 can be configured to be spatially separated from the edge of the insertion portion 51 by a specific distance in the horizontal direction. In this case, for example, the melting point of the cap connection 52 can be approximately 100°C to 1400°C. That is, welding can be performed between the cap connection 52 and the cap 40 by applying heat of 100°C to 1400°C.

[0147] According to the above embodiments of the present disclosure, the welding area of ​​the cap connection portion 52 can be formed to be spaced apart from the injection port 42 (or the insertion portion 51) to prevent electrolyte from flowing out into the welding area.

[0148] Compared to seam welding, the thermal joint between the cap 40 and the cap connection portion 52 of the plug 50 can have a smaller area to be welded. For example, in the case of a 4680 battery cell, the diameter of the cap 40 to which seam welding is performed is approximately 46 mm, and the diameter D2 of the cap connection portion 52 of the plug 50 to which thermal joint between the cap 40 and the cap connection portion 52 is performed can be approximately 10 mm to 15 mm. Since thermal deformation due to heat accumulation may occur in a narrow area during welding, tack welding may be necessary. In addition, the high temperature around the injection port 42 may also cause fire problems in terms of welding defects and heat concentration due to the generation of vaporized gas in the electrolyte. However, according to the above-described embodiment of the present disclosure, the diameter D2 of the cap connection portion 52 is formed to be larger than the diameter D1 of the insertion portion 51, thereby reducing thermal deformation during welding and solving the problems of welding defects and fire.

[0149] That is, the sealing of cap 40 and plug 50 can be achieved by first press-fitting plug 50 into injection port 42 to obtain temporary sealing force, and then welding cap connection 52 of plug 50 and cap 40 to obtain final sealing force.

[0150] The final sealing force can even be greater than the temporary sealing force. For example, based on a He leak, the final sealing force that can be obtained by welding can be approximately greater than or equal to 10. -7 atm·cc / s. That is, high airtightness can be ensured.

[0151] According to the above embodiments of this disclosure, since welding is performed after obtaining temporary sealing force, phenomena such as the formation of gas channels or the occurrence of cracks during the welding process can be prevented, thereby preventing defects in the cover connection portion 52.

[0152] Furthermore, according to the embodiments described above in this disclosure, since welding W is performed after a temporary sealing force is obtained, it is possible to prevent electrolyte vapor from leaking to the outside and being ignited during the welding process. Therefore, events such as fires or explosions caused by thermal runaway in vehicles comprising multiple battery cells can be prevented or delayed.

[0153] Furthermore, the insertion portion 51, configured to obtain a temporary sealing force, and the cover connection portion 52, configured for thermal bonding, are spaced apart in the axial direction, thereby preventing direct contact between electrolyte vapor and the welding area.

[0154] As a comparative example, one could consider a method where a plastic ball is inserted after electrolyte injection, followed by the insertion of a separate stopper to complete the welding. In this case, two unit components are required: the plastic ball and the stopper. The process involves three steps: inserting the plastic ball, inserting the stopper, and welding.

[0155] Compared with the comparative example, according to an embodiment of the present disclosure, only one plug 50 component may be included without an additional configuration. That is, the insertion portion 51 of the plug 50 may be configured to be press-fitted into the injection port 42, and the lid coupling portion 52 of the plug 50 may be configured to be welded to the lid 40. Therefore, compared with the comparative example, the number of components is reduced to 1, and the number of processes is reduced to 2, which may simplify the method.

[0156] In addition, according to the comparative example, when a separate plug is inserted after inserting a plastic ball, the welding area of the plastic ball and the plug should be configured to be spaced apart at a constant distance in the longitudinal direction to prevent the electrolyte vapor from being ignited due to the welding heat. At this time, when a deep injection port is manufactured in the depth direction, the width of the injection port should be narrowed to avoid interference with the electrode assembly, and in this case, the liquid injection efficiency may be reduced.

[0157] Compared with the comparative example, according to an embodiment of the present disclosure, since both the temporary sealing force and the final sealing force are provided by one plug 50 component, the length of the tube portion defining the injection port 42 in the winding axis direction can be reduced, thereby preventing the tube portion from interfering with the electrode assembly. Therefore, the inner diameter R1 of the injection port 42 can be increased, and the liquid injection efficiency can be improved. In addition, the phenomenon that the welding heat of the plug 50 affects the electrode assembly or the electrolyte can be minimized.

[0158] Figure 13 is a cross-sectional view showing a state in which a plug according to another embodiment of the present disclosure is inserted into a lid. Figure 14 is a cross-sectional view showing a state in which a plug and a lid are coupled according to another embodiment of the present disclosure.

[0159] The structures of the lid 40 and the plug 50 and the welding process of the lid 40 and the plug 50 are the same as those described Figures 9 to 12 and thus a repeated description thereof will be omitted.

[0160] The side surface of the insertion portion 51 may be an inclined surface inclined at a specific angle (θ).

[0161] The diameter D11 of the lower surface of the insertion portion 51 may be formed to be smaller than the diameter D12 of the upper surface of the insertion portion 51 (D11 < D12). Therefore, the insertion portion 51 may have a tapered shape that gradually expands from the lower surface toward the upper surface. That is, the insertion portion 51 may have, for example, a truncated cone shape. At this time, for example, the inclination angle (θ) of the side surface of the insertion portion 51 may be an angle inclined about 10 to 20 degrees with respect to the winding axis direction.

[0162] At this time, the inner diameter R1 of the injection port 42 may be larger than the diameter D11 of the lower surface of the insertion portion 51 and smaller than the diameter D12 of the upper surface of the insertion portion 51 (D11 < R1 < D12).

[0163] For example, the diameter D12 of the upper surface of the insertion portion 51 can be 0.05 mm to 0.40 mm larger than the inner diameter R1 of the injection port 42. For example, the diameter D12 of the upper surface of the insertion portion 51 can be approximately 0.05 mm to 0.20 mm larger than the inner diameter R1 of the injection port 42. For example, the diameter D12 of the upper surface of the insertion portion 51 can be approximately 0.05 mm to 0.10 mm larger than the inner diameter R1 of the injection port 42. For example, the overlap dimension between the diameter D12 of the upper surface of the insertion portion 51 and the inner diameter R1 of the injection port 42 in the radial direction can be approximately 0.025 mm to 0.20 mm.

[0164] According to the embodiments of this disclosure, the lower surface of the insertion part 51 can be easily inserted into the injection port 42 due to its relatively small diameter, and the upper surface of the insertion part 51 can be formed to be larger than the inner diameter R1 of the injection port, thereby effectively sealing the injection port 42. The plug 50 can be inserted into the injection port 42 by mechanical press-fitting. At this time, the upper outer peripheral surface of the insertion part 51 can press tightly against the inner peripheral surface of the injection port 42 and interfere with it. Therefore, leakage of internal electrolyte vapor or gas to the outside can be effectively blocked.

[0165] When increasing the press fit strength during the press fit of the plug 50 to ensure high sealing performance, in severe cases, the cap 40 may sag downwards, causing physical damage to the electrode assembly 20, and in this case, there is a risk of short circuit. In this disclosure, the overlap size of the plug 50 and the cap and the press fit load can be set to minimize the downward sag of the cap 40.

[0166] In other words, the plug 50 is press-fitted to prevent electrolyte vapor from leaking to the outside, which can prevent welding defects and fire during the laser welding process. That is, by mixing the leaked electrolyte vapor into the cap connection 52, the occurrence of welding defects and the risk of fire can be prevented. In other words, it can prevent electrolyte vapor released to the outside due to the increase in the partial pressure of flammable vapor caused by the welding heat (heat conduction) during welding from coming into contact with the molten material.

[0167] Figure 15 This is a cross-sectional view showing the connection state of the cap and plug according to yet another embodiment of the present disclosure.

[0168] The cap 40 may include a main body 41 and a plug connection 43. The cap 40 may have an injection port (e.g., Figure 11 The periphery of the inlet 42) is formed in the radial direction with a step. Based on this step, the cover 40 can be divided into a main body 41 and a plug connection 43.

[0169] The main body 41 can be configured to be connected to the tank 10. The edge of the main body 41 can make perpendicular contact with the open end of the tank 10. The main body 41 can be welded W along the circumferential direction of the portion that contacts the open end of the tank 10, which can be defined as a seam weld (as described above).

[0170] At this time, the cap connecting portion 52 of the plug 50 and the main body portion 41 of the cap 40 can be configured to face each other in the radial direction and be welded together.

[0171] The plug connection 43 may be recessed around the injection port 42 and downward relative to the main body 41 in the winding axis direction, and may be configured to allow the cap connection 52 to be placed.

[0172] The plug connector 43 can be positioned closer to the radially inner side than the main body 41. The upper surface of the plug connector 43 can be configured to be lower than the upper surface of the main body 41. That is, a step is formed between the plug connector 43 and the main body 41, and this step can be an annular shape extending in the circumferential direction around the injection port 42. This step can be formed by forging.

[0173] The thickness of the plug connecting portion 43 in the winding axis direction can be made thinner than the thickness of the main body portion 41 in the winding axis direction. The plug 50 can be mounted on the plug connecting portion 43. The cap connecting portion 52 of the plug 50 can be mounted on the plug connecting portion 43.

[0174] See Figure 15 The lower edge of the cap connection portion 52 can be rounded (r). When connecting to the step formed between the body portion 41 of the cap 40 and the plug connection portion 43, this rounding (r) minimizes any step or interference, thereby enabling a precise and stable connection without overlapping with the cap 40. This not only improves the ease of assembly but also reduces mechanical stress concentration. Furthermore, the shape of the cap connection portion 52 is not limited to the above embodiment and can be designed and modified in various ways. Additionally, other corner portions can also be rounded (r) in the same manner. This further improves the overall assemblability and durability of the component.

[0175] According to the above embodiments of this disclosure, the structure of the cap connection portion 52, which can accommodate the plug 50, can be formed by forging the periphery of the injection port 42.

[0176] Furthermore, according to the above-described embodiment of this disclosure, the plug connection portion 43 to which the plug 50 is connected is formed to be recessed downward toward the electrode assembly 20, so that even when the plug 50 is connected, the total height of the battery cell 1 can remain constant. That is, when the plug 50 is connected to the cover 40, the upper surface of the plug 50 will not protrude upward beyond the upper surface of the cover 40. In other words, no deviation in the total height of the battery cell 1 can occur. Therefore, the contact portion and / or contact area with components (e.g., heat sinks) provided on the upper side of the cover 40 can be maximized without being limited by the plug 50. As a result, improvements can be made to the battery cell 1 and / or battery pack (e.g., Figure 19 The cooling performance of the battery pack (P).

[0177] Figure 16 This is a cross-sectional view showing a plug according to yet another embodiment of the present disclosure. Figure 17 This is a cross-sectional view showing the connection state of the cap and plug according to yet another embodiment of the present disclosure.

[0178] The construction of cap 40 and stopper 50, and the welding process of cap 40 and stopper 50, and references. Figures 9 to 15 The descriptions are the same, so repeated descriptions of them will be omitted.

[0179] The cap connecting portion 52 and the insertion portion 51 of the plug 50 may have substantially the same thickness in the winding axis direction. The cap connecting portion 52 and the insertion portion 51 of the plug 50 may be integrally formed. That is, the plug 50 may be bent between the cap connecting portion 52 and the insertion portion 51.

[0180] The stopper 50 can be configured to be molded by a stretching method. A stretching method can refer to a processing method used to stretch and thin metal into a desired shape. A stretching method can be a process of stretching and drawing a material such as a sheet or wire using a die. For example, a deep drawing process can be a method of molding a plate into a deep container shape using a punch or die. Specifically, the stopper 50 can be manufactured by molding using a deep drawing method. Specifically, the stopper 50 can be manufactured by fixing the ends of a stopper preform and extruding the center of a stopper preform, which is a plate-shaped material of a certain thickness.

[0181] According to the above-described embodiment of this disclosure using the stretching method, the radial distance between the cap connecting portion 52 and the insertion portion 51 can be formed to be relatively longer compared to the forging method. Therefore, direct contact between the electrolyte evaporation gas generated due to welding heat and the cap connecting portion 52 can be prevented. In other words, the electrolyte evaporation path can be further extended. Therefore, welding defects caused by the evaporation heat of the electrolyte can be prevented.

[0182] According to the above embodiments of this disclosure, the stopper 50 is manufactured by a stretching method, which reduces the weight of the stopper 50, thereby contributing to a reduction in the weight of the battery cell 1. Furthermore, it lowers the manufacturing cost of the stopper 50, and the processing method for the stopper 50 is simple and easy, which shortens the manufacturing time.

[0183] Figure 18 This is a flowchart of a method for manufacturing a battery cell, in which the injection port sealing structure of this disclosure is applied. In the following text, reference will be made to... Figure 18 A method for manufacturing battery cells according to embodiments of the present disclosure is described. For ease of description, reference may be made to... Figures 1 to 17 The accompanying diagram is used to describe it.

[0184] First, a canister 10 and an electrode assembly 20 (S1) can be prepared. In the canister 10, the first electrode terminal 13 is fixed to the bottom 12 in an insulated and sealed manner. The electrode assembly 20 includes a first current collector 31 and a second current collector 32 respectively welded to the first electrode and the second electrode at both ends.

[0185] Subsequently, the step of covering the open end with a cap 40 when housing the electrode assembly 20 in the can 10 may be included (S2).

[0186] With the first current collector 31 aligned with the bottom 12 of the can 10, the electrode assembly 20 can be housed in the can 10. At this time, the insulator 19 can be inserted between the first current collector 31 and the bottom 12 of the can 10 to electrically insulate the first current collector 31 from the bottom 12.

[0187] The process may include the step of bonding the edge of the lid 40 to the can 10 (S3). The lid 40 and the can 10 may be thermally bonded.

[0188] The circumference of the front end of the side wall portion 11 of the battery can 10 and the circumference of the edge of the cover 40 can be welded together in the circumferential direction. The contact point between the open end of the can 10 and the cover 40 can be connected together. For example, the connection point between the open end of the can 10 and the cover 40 can be connected by welding. For example, the cover 40 can be connected to the can 10 by butt welding. This can be defined as a seam welding method.

[0189] Additionally, the first current collector 31 can be thermally bonded to the first electrode terminal 13 before the edge of the lid 40 is joined to the can 10. Furthermore, the open end of the can 10 is sealed by covering it with the lid 40, and in order to allow the second current collector 32 to be electrically connected to the can 10 and / or the lid 40, which serves as the second electrode terminal 15, the second current collector 32 can be joined to the can 10 and / or the lid 40, and the lid 40 can be thermally bonded to the can 10.

[0190] Next, the process may include the step of injecting electrolyte into the battery canister 10 through the injection port 42 of the cap 40 (S4). According to one embodiment, before sealing the injection port 42 with the stopper 50, the process may further include the step of removing residual electrolyte from the injection port 42 after the electrolyte injection is completed.

[0191] Next, a step (S5) may be included whereby the stopper 50 is inserted into the injection port 42 after the electrolyte is injected. The insertion portion 51 of the stopper 50 may be configured to be inserted into the injection port 42. For example, the insertion portion 51 may be inserted into the injection port 42 in a press-fit manner. The insertion portion 51 may be fitted into the injection port 42 to initially seal the injection port 42.

[0192] According to the above-described embodiment of this disclosure, the plug 50 has an insertion portion 51, thereby allowing the insertion portion 51 to be press-fitted into the injection port 42 and held in place even before welding. Furthermore, it can prevent the plug 50 from detaching from the injection port 42 when transferred to the welding apparatus. That is, before welding the cap 40 and the plug 50, a temporary sealing force can be obtained first by press-fitting the insertion portion 51 of the plug 50 into the injection port 42.

[0193] Finally, the step of welding the plug 50 and the cap 40 may be included (S6).

[0194] The final sealing process can first obtain a temporary sealing force by press-fitting the plug 50 into the injection port 42, and then obtain a final sealing force by welding and sealing the cap connection 52 of the plug 50 and the cap 40.

[0195] For example, the cap connection 52 of the stopper 50 and the main body 41 of the cap 40 can be laser welded. Laser welding can be defined as a process of melting and joining metals using a laser beam with high energy density.

[0196] According to the above embodiments of this disclosure, since welding is performed after obtaining temporary sealing force, phenomena such as the formation of gas channels or the occurrence of cracks during the welding process can be prevented, thereby preventing defects in the cover connection portion 52.

[0197] Furthermore, according to the above embodiments of this disclosure, since welding is performed after obtaining temporary sealing force, it is possible to prevent electrolyte vapor from leaking to the outside and being ignited during the welding process.

[0198] Figure 19 This is a view used to describe a battery pack according to an embodiment of the present disclosure. Figure 20 It is used to describe including Figure 19 A view of the vehicle with its battery pack.

[0199] Reference Figure 19The battery pack P according to this disclosure may include at least one battery cell 1 as described above. Additionally, the battery pack P according to this disclosure may include a battery pack housing 2 capable of accommodating at least one battery cell 1. The battery pack P can be configured using a battery module as an intermediate component, or it can be configured directly without a battery module as shown. Since the battery cell 1 itself has a large volume, there are no particular difficulties in implementing the battery pack P even without using an intermediate structure called a battery module.

[0200] In addition, the battery pack P may also include various components other than the battery cell 1, such as components of the battery pack P known at the time of filing of this disclosure, such as BMS, relays, current sensors, etc.

[0201] Multiple battery cells 1 can be included in a battery pack P. The battery cells 1 can be arranged in a predetermined number of rows, and can be arranged such that the first electrode terminal 13 and the second electrode terminal 15 are both located on the upper side of each battery cell 1. Therefore, when multiple battery cells 1 are electrically connected, the positive and negative electrodes can be connected in one direction, thereby simplifying the electrical connection structure. Therefore, energy density can be increased by increasing the number of battery cells 1 that can be installed in the same space, and electrical wiring can be facilitated. Thus, excellent space efficiency and high electrical wiring efficiency result in significant improvements during the assembly of electric vehicles and the assembly and maintenance of the battery pack P. Furthermore, as described above, each battery cell 1 can have a higher energy density than conventional cells. The battery pack P, with its increased energy density in this way, can store the same amount of energy while reducing its volume and weight.

[0202] Therefore, as Figure 20 As shown, if a battery pack P using these battery cells 1 is installed in a vehicle such as a vehicle M that uses electricity as its energy source, the vehicle's range per unit of energy can be further extended.

[0203] Additionally, the battery pack P may also include a heat sink. The battery pack housing 2 can accommodate the heat sink. For example, the heat sink can be positioned below the battery cell 1. In this case, the heat sink can contact the cover 40 of the battery cell 1 (e.g., Figure 9 The cap 40) and / or the stopper 50 (e.g., Figure 9 50 plugs).

[0204] See Figure 20 The vehicle M according to this disclosure may include at least one battery pack P according to this disclosure.

[0205] The battery cell 1 according to this disclosure can be applied to vehicles such as electric vehicles or hybrid vehicles. That is, a vehicle M according to this disclosure may include the battery cell 1 according to this disclosure or the battery pack P according to this disclosure. Furthermore, in addition to the battery cell 1 or the battery pack P, the vehicle M according to this disclosure may also include various other components included in the vehicle. For example, in addition to the battery cell 1 according to this disclosure, the vehicle M according to this disclosure may also include a body, an electric motor, control devices such as an electronic control unit (ECU), etc. The vehicle M includes four-wheeled vehicles and two-wheeled vehicles. According to embodiments of this disclosure, the vehicle M can be operated by receiving power from the battery pack P.

[0206] The present disclosure has been described above with reference to a limited number of embodiments and accompanying drawings, but the present disclosure is not limited thereto, and it will be apparent to those skilled in the art that various modifications and variations can be made to it within the scope of the technical aspects of the present disclosure and the appended claims and their equivalents.

Claims

1. A battery cell, the battery cell comprising: An electrode assembly is formed by winding a first electrode, a second electrode, and a diaphragm inserted between the first electrode and the second electrode around a winding axis; A can, the can being configured to accommodate the electrode assembly by means of an open end formed on one side; A cap that covers the open end and has an injection port formed therein; as well as A stopper, the stopper being configured to seal the injection port. The plug includes an insertion portion and a cap connecting portion. The insertion portion is configured to be inserted into the injection port, and the cap connecting portion extends upward from the insertion portion in the direction of the winding shaft and is disposed on the cap. The diameter of the insertion part is larger than the inner diameter of the injection port.

2. The battery cell according to claim 1, in, The tolerance between the diameter of the insertion part and the inner diameter of the injection port is 50 μm to 150 μm.

3. The battery cell according to claim 1, in, The diameter of the cover connecting part is larger than the diameter of the insertion part.

4. The battery cell according to claim 3, in, The diameter of the cap connection is at least 1.1 to 1.5 times the diameter of the insertion part.

5. The battery cell according to claim 1, in, The side surfaces of the insertion portion and the cover connection portion are spaced apart from each other in the horizontal direction.

6. The battery cell according to claim 1, in, The side surface of the insertion part is an inclined surface tilted at a specified angle.

7. The battery cell according to claim 6, in, The diameter of the lower surface of the insertion part is formed to be smaller than the diameter of the upper surface of the insertion part, and The inner diameter of the injection port is greater than the diameter of the lower surface of the insertion part and smaller than the diameter of the upper surface of the insertion part.

8. The battery cell according to claim 1, in, The cap includes a body portion and a plug connector portion, the plug connector portion being recessed downward relative to the body portion in the direction of the winding axis around the injection port and configured to allow placement of the cap connector portion.

9. The battery cell according to claim 8, in, The cap connection portion of the plug and the main body portion of the cap face each other in the radial direction and are welded together.

10. The battery cell according to claim 1, in, The can and the lid are thermally joined.

11. A method for manufacturing a battery cell according to any one of claims 1 to 10, the method comprising the following steps: With the electrode assembly housed in the container, cover the open end of the container with a lid; The edge of the lid is heat-bonded to the can; The electrolyte is injected into the interior of the tank through the injection port of the cap; The injection port is sealed by inserting the plug into it; as well as The cap is welded to the cap coupling, which is formed to extend upward from the insertion portion of the plug in the direction of the winding shaft and is mounted on the cap.

12. A battery pack comprising battery cells according to any one of claims 1 to 10.

13. A vehicle equipped with a battery pack according to claim 12.

Images