Battery cell, method of manufacturing the same and battery module

Abstract

To provide a battery cell which may address defects caused by foreign substances occurring when coupling an electrode terminal to a current collector, a method of manufacturing the same and a battery module.SOLUTION: The present disclosure provides a battery cell including: a cell case 110 including a sidewall 111 forming an accommodation space therein and a top plate 112 having a through-hole formed therein; an electrode terminal 140 coupled to the through-hole and having a coupling groove 145 formed in a bottom portion; an electrode assembly 120 disposed in the accommodation space of the cell case; and a first current collector 130 electrically connecting the electrode terminal to the electrode assembly. The first current collector includes a connection terminal 133 having a protrusion 133b fitted to the coupling groove. The protrusion is coupled to the electrode terminal by welding performed on an outer side of the cell case in a state of being fitted to the coupling groove. A thickness of the connection terminal in a welded region where the protrusion and the electrode terminal are welded has a value equal to or greater than a value of a thickness of the electrode terminal.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a battery cell (secondary battery) capable of being charged and discharged, a method for manufacturing the battery cell, and a battery module. [Background technology]

[0002] Unlike primary batteries, secondary battery cells are convenient in that they can be charged and discharged, and are therefore attracting much attention as a power source for various mobile devices, electric vehicles, energy storage devices, and the like.

[0003] Secondary battery cells can be manufactured as pouch-type cells or can-type cells. Pouch-type cells have a structure in which an electrode assembly is housed inside a flexible cell case (pouch). Can-type cells have a structure in which an electrode assembly is housed inside a rigid cell case (can), and can be constructed as cylindrical cells, prismatic cells, coin cells, etc. Summary of the Invention [Problem to be solved by the invention]

[0004] The secondary battery cell may include an electrode assembly and a cell case that houses the electrode assembly. The electrode assembly may be connected to a current collector, and the current collector may be welded to an electrode terminal of the battery cell to be electrically connected to the electrode terminal.

[0005] In a conventional battery cell, a current collector and an electrode assembly are joined together, and then the electrode assembly is inserted into a cell case. A horn for ultrasonic welding is inserted into a hollow space formed in the center of the electrode assembly, and the current collector and electrode terminal are ultrasonically welded to electrically connect the current collector and the terminal.

[0006] However, when ultrasonic welding is performed through the hollow portion of the electrode assembly while the electrode assembly is inserted inside the cell case, welding foreign matter such as fumes and spatters is formed inside the battery cell, which can cause defects in the battery cell.

[0007] According to an aspect of the present disclosure, it is possible to provide a battery cell, a manufacturing method thereof, and a battery module capable of improving defects caused by foreign matter that occurs when connecting an electrode terminal and a current collector.

[0008] According to one aspect of the present disclosure, it is possible to provide a battery cell that can prevent foreign matter (impurities) caused by welding between an electrode terminal and a current collector from affecting the internal structure of the battery cell, a manufacturing method thereof, and a battery module.

[0009] According to one aspect of the present disclosure, a battery cell, a manufacturing method thereof, and a battery module capable of improving damage to an electrode assembly caused by welding heat can be provided.

[0010] According to one aspect of the present disclosure, it is possible to provide a battery cell capable of improving the rigidity of an electrode terminal, a manufacturing method thereof, and a battery module.

[0011] According to one aspect of the present disclosure, it is possible to provide a battery cell that can easily perform a process of electrically connecting an electrode terminal to another battery cell or battery module, a manufacturing method thereof, and a battery module.

[0012] According to one aspect of the present disclosure, it is possible to provide a battery cell in which a stable electrical connection between an electrode terminal and a current collector can be ensured, a manufacturing method thereof, and a battery module.

[0013] According to one aspect of the present disclosure, it is possible to provide a battery cell, a manufacturing method thereof, and a battery module that can improve the weldability and / or working speed of electrode terminals.

[0014] The battery cell and / or battery module of the present disclosure may be widely applied in the field of green technology, such as electric vehicles, battery charging stations, and other battery-based solar power generation and wind power generation. Furthermore, the battery cell and / or battery module of the present disclosure may be used in eco-friendly electric vehicles, hybrid vehicles, etc., which reduce air pollution and greenhouse gas emissions to prevent climate change. [Means for solving the problem]

[0015] A battery cell according to the present disclosure includes a cell case including a sidewall forming an accommodating space therein and an upper plate having a through hole formed therein; an electrode terminal connected to the through hole and having a coupling groove formed in a lower portion thereof; an electrode assembly disposed in the accommodating space of the cell case; and a first current collector electrically connecting the electrode terminal and the electrode assembly, wherein the first current collector includes a connecting terminal having a protrusion fitted in the coupling groove, and the protrusion is coupled to the electrode terminal by welding from the outside of the cell case while being fitted in the coupling groove, and a thickness of the connecting terminal at a welded portion between the protrusion and the electrode terminal may be greater than or equal to a thickness of the electrode terminal.

[0016] According to one embodiment, the protrusion may be provided as a solid type having a filled interior.

[0017] According to an embodiment, the first current collector may further include a current collecting plate electrically connected to a first electrode tab of the electrode assembly, and the current collecting plate may be connected to the connection terminal.

[0018] According to an embodiment, the connection terminal may further include a support portion coupled to the current collecting plate, and the protrusion may extend from the support portion and have a shape that passes through an opening formed in the current collecting plate.

[0019] According to an embodiment, the current collecting plate and the connection terminal may be manufactured separately and then coupled to each other.

[0020] According to another embodiment, the current collecting plate and the connection terminal may be integrally formed.

[0021] According to an embodiment, the side surface of the protrusion may include an inclined surface, and the inclined surface may have a shape in which the width at the upper side is narrower than that at the lower side.

[0022] According to one embodiment, the cell casing may have a circular cross section, and the through hole may be formed in the center of the upper plate.

[0023] According to an embodiment, the electrode terminals may be riveted to the through holes of the cell casing.

[0024] The battery cell according to an embodiment may further include a first gasket disposed between the electrode terminal and the through hole and having electrical insulation properties.

[0025] According to an embodiment, the electrode terminal may have a welding groove formed on an upper portion of the coupling groove for welding between the electrode terminal and the protrusion.

[0026] According to one embodiment, the welding groove may comprise a spiral shape in a plane or may comprise at least one closed curve.

[0027] According to one embodiment, the side wall has a tube shape, the upper plate has a plate shape covering an upper side of the receiving space, and the side wall and the upper plate may be integrally formed.

[0028] According to another embodiment, the side wall may have a tubular shape, the upper plate may have a plate shape covering the upper side of the receiving space, and the side wall and the upper plate may be joined to each other by welding.

[0029] The battery cell according to an embodiment further includes a cap plate that covers a lower side of the receiving space of the cell case, and the cap plate may be crimped or welded to the cell case.

[0030] According to one embodiment, the battery cell further includes a second current collector electrically connected to the second electrode tab of the electrode assembly and a cap plate covering a lower side of the accommodating space of the cell case, and the second current collector may be electrically connected to at least one of the cap plate or a side wall of the cell case.

[0031] A method for manufacturing a battery cell according to the present disclosure includes the steps of: riveting an electrode terminal to a through-hole formed in an upper plate of a cell case having an open bottom; electrically connecting a first current collector to an electrode assembly; inserting the electrode assembly into an accommodating space of the cell case; and welding the electrode terminal to the first current collector, wherein the first current collector includes a connecting terminal having a protrusion that fits into a coupling groove formed in a lower part of the electrode terminal, and the welding step applies energy from outside the cell case with the protrusion fitted into the coupling groove to weld the electrode terminal to the protrusion, and a thickness of the connecting terminal at a welded portion between the protrusion and the electrode terminal may be equal to or greater than a thickness of the electrode terminal.

[0032] According to one embodiment, the cell case includes a tube-shaped side wall that forms the storage space and a plate-shaped upper plate that covers the upper side of the storage space, and the side wall and the upper plate may be integrally formed.

[0033] According to an embodiment, the first current collector further includes a current collecting plate electrically connecting the first electrode tab of the electrode assembly and the connecting terminal, and the current collecting plate and the connecting terminal may be separately manufactured and then joined by welding.

[0034] According to another embodiment, the first current collector may further include a current collecting plate electrically connecting a first electrode tab of the electrode assembly and the connecting terminal, and the current collecting plate and the connecting terminal may be integrally formed by forging.

[0035] According to an embodiment, the electrode terminal may have a welding groove formed on an upper portion of the coupling groove for welding between the electrode terminal and the protrusion, and the welding step may include irradiating a laser along the welding groove to weld the electrode terminal and the protrusion.

[0036] According to an embodiment, the method for manufacturing a battery cell further includes providing a cap plate on the open lower side of the cell case, and the providing of the cap plate may be performed by crimping or welding the cap plate to the cell case.

[0037] A battery module according to the present disclosure includes a plurality of battery cells and a module housing that accommodates the plurality of battery cells, wherein at least one of the plurality of battery cells includes a cell case including a sidewall that forms an accommodation space therein and an upper plate having a through hole formed therein, an electrode terminal that is coupled to the through hole and has a coupling groove formed in a lower portion thereof, an electrode assembly that is disposed in the accommodation space of the cell case, and a first current collector that electrically connects the electrode terminal and the electrode assembly, wherein the first current collector includes a connecting terminal having a protrusion that is fitted into the coupling groove, and the protrusion is coupled to the electrode terminal by welding from outside the cell case while being fitted into the coupling groove, and a thickness of the connecting terminal at a welded portion between the protrusion and the electrode terminal may be greater than or equal to a thickness of the electrode terminal. [Effects of the Invention]

[0038] According to an embodiment of the present disclosure, defects caused by foreign matter generated when bonding an electrode terminal and a current collector can be improved.

[0039] According to an embodiment of the present disclosure, it is possible to prevent foreign matter (impurities) caused by welding between an electrode terminal and a current collector from affecting the internal structure of a battery cell.

[0040] According to an embodiment of the present disclosure, it is possible to improve the electrode assembly from being damaged by welding heat.

[0041] According to an embodiment of the present disclosure, the rigidity of the electrode terminal can be improved.

[0042] According to an embodiment of the present disclosure, a process of electrically connecting the electrode terminals to other battery cells, battery modules, etc. can be easily performed.

[0043] According to an embodiment of the present disclosure, a stable electrical connection between the electrode terminal and the current collector can be ensured.

[0044] According to an embodiment of the present disclosure, the weldability and / or working speed of the electrode terminal can be improved. [Brief explanation of the drawings]

[0045] [Figure 1] FIG. 1 is a perspective view of a battery cell according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the battery cell shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line II' in FIG. [Figure 4] 4A and 4B are a cross-sectional view and a partially enlarged view showing a portion where an electrode terminal is provided in the cross-sectional view shown in FIG. 3. [Figure 5] 5 is a cross-sectional view showing a modified embodiment of the battery cell shown in FIG. 4. [Figure 6] 5 is a cross-sectional view showing a modified embodiment of the battery cell shown in FIG. 4. [Figure 7] FIG. 10 is a perspective view showing another embodiment of the first current collector. [Figure 8a] 8 is a cross-sectional view showing a state in which the first current collector shown in FIG. 7 is applied to the cross-section of FIG. 4. FIG. [Figure 8b] 8b is a cross-sectional view showing a modified embodiment of the battery cell shown in FIG. 8a. [Figure 8c] 8b is a cross-sectional view showing a modified embodiment of the battery cell shown in FIG. 8a. [Figure 9] FIG. 10 is a cross-sectional view of a battery cell according to another embodiment. [Figure 10] FIG. 10 is a cross-sectional view of a battery cell according to yet another embodiment. [Figure 11] FIG. 10 is a cross-sectional view of a battery cell according to yet another embodiment. [Figure 12] FIG. 12 is a cross-sectional view showing the electrode terminal shown in FIG. 11 in a state before being riveted. [Figure 13] FIG. 12 is a plan view of the electrode terminal shown in FIG. [Figure 14] FIG. 14 is a plan view showing a modified example of the electrode terminal shown in FIG. [Figure 15] 1 is a flowchart illustrating a method of manufacturing a battery cell according to an embodiment. [Figure 16a] 10A to 10C are cross-sectional views illustrating a method for manufacturing a battery cell. [Figure 16b] 10A to 10C are cross-sectional views illustrating a method for manufacturing a battery cell. [Figure 16c] 10A to 10C are cross-sectional views illustrating a method for manufacturing a battery cell. [Figure 16d] 10A to 10C are cross-sectional views illustrating a method for manufacturing a battery cell. [Figure 16e] 10A to 10C are cross-sectional views illustrating a method for manufacturing a battery cell. [Figure 17] 15A to 15C are cross-sectional views illustrating a welding step for the electrode terminal shown in FIGS. 11 to 14. [Figure 18] FIG. 1 is a perspective view of a battery module according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0046] The same reference numbers or symbols in the drawings attached to this specification indicate parts or components that perform substantially the same functions. For ease of explanation and understanding, the same reference numbers or symbols may be used in different embodiments. In other words, even if components having the same reference numbers are shown in multiple drawings, it does not mean that all of the multiple drawings represent one embodiment.

[0047] In the following description, the singular includes the plural unless the context clearly indicates otherwise. Terms such as "comprise" or "comprise" are intended to specify the presence of a feature, numeral, step, operation, component, part, or combination thereof described in the specification, and are understood not to preclude the presence or possibility of addition of one or more other features, numerals, steps, operations, components, parts, or combinations thereof.

[0048] In the following description, expressions such as upper, top, lower, bottom, side, front, rear, etc. are expressed based on the direction shown in the drawing, and may be expressed differently if the direction of the object is changed.

[0049] Furthermore, in this specification and claims, terms including ordinal numbers such as "first" and "second" may be used to distinguish between elements. Such ordinal numbers are used to distinguish between identical or similar elements, and the use of such ordinal numbers should not be interpreted as limiting the meaning of the terms. For example, the order of use or arrangement of elements combined with such ordinal numbers should not be interpreted as limiting. If necessary, each ordinal number may be used interchangeably.

[0050] The present disclosure will now be described in detail with reference to the accompanying drawings, which are illustrative only and are not intended to limit the present disclosure to the specific embodiments illustratively described.

[0051] FIG. 1 is a perspective view of a battery cell 100 according to one embodiment, FIG. 2 is an exploded perspective view of the battery cell 100 shown in FIG. 1, FIG. 3 is a cross-sectional view along line II' in FIG. 2, and FIG. 4 is a cross-sectional view and a partially enlarged view showing the portion where the electrode terminal 140 is provided in the cross-sectional view shown in FIG. 3.

[0052] 1 to 4, a battery cell 100 according to an embodiment may include a cell casing 110 including a sidewall 111 forming an internal receiving space, an upper plate 112 having a through hole 113 formed therein, an electrode terminal 140 connected to the through hole 113 and having a coupling groove 145 formed in a bottom portion thereof, an electrode assembly 120 disposed in the receiving space of the cell casing 110, and a first current collector 131 electrically connecting the electrode terminal 140 to the electrode assembly 120. The first current collector 131 may include a connecting terminal 133 having a protrusion 133b fitted into the coupling groove 145. The protrusion 133b may be fitted into the coupling groove 145 and coupled to the electrode terminal 140 by welding from the outside of the cell casing 110. A thickness T2 of the connecting terminal 133 at a welded portion WA of the protrusion 133b and the electrode terminal 140 may be greater than or equal to a thickness T1 of the electrode terminal 140.

[0053] The battery cell 100 according to the present disclosure may be, but is not limited to, a cylindrical cell, and the present disclosure will explain the battery cell 100 according to one embodiment by taking a cylindrical cell as an example.

[0054] The cell casing 110 may include a sidewall 111 that forms an internal storage space and an upper plate 112 having a through hole 113 formed therein. The storage space may be formed by the sidewall 111 and the upper plate 112 of the cell casing 110. The cell casing 110 may have a cylindrical shape with one side open. The cell casing 110 may have a hollow cylindrical shape with a circular cross section.

[0055] The side wall 111 may have a tube shape, and the top plate 112 may have a plate shape that covers the top side of the receiving space.

[0056] The side wall 111 may have a circular tube shape. The top plate 112 may have an overall flat plate shape. In the cell casing 110, the thicknesses of the top plate 112 and the side wall 111 may vary. For example, the top plate 112 and the side wall 111 may have the same thickness, or the top plate 112 may be thicker than the side wall 111. The cell casing 110 may include a metal material such as aluminum or an aluminum alloy, and the material of the cell casing 110 may vary.

[0057] 1 to 4, the side wall 111 and the upper plate 112 of the cell casing 110 may be integrally formed. For example, the cell casing 110 may be manufactured by deep drawing a metal sheet to have the side wall 111 and the upper plate 112 integrally formed. When the cell casing 110 is integrally formed, a process of joining the side wall 111 and the upper plate 112 is not required, which simplifies the manufacture of the cell casing 110 and / or the battery cell 100 and improves workability.

[0058] However, the cell case 110 of the present disclosure is not limited to a configuration in which the side wall 111 and the upper plate 112 are integrally formed, and the side wall 111 and the upper plate 112 may be manufactured separately and then joined or bonded to each other by welding or the like (see FIG. 9).

[0059] A through-hole 113 may be formed in the upper plate 112 of the cell casing 110. The through-hole 113 may be provided for coupling with an electrode terminal 140. The cell casing 110 has a circular cross-sectional shape, and the through-hole 113 may be formed in the center of the upper plate 112. In this case, the electrode terminal 140 coupled to the through-hole 113 may be disposed in the center of the upper plate 112.

[0060] The electrode terminal 140 may be coupled to the through-hole 113. At least a portion of the electrode terminal 140 may be exposed to the outside of the cell casing 110. When the first current collector 131 is connected to a positive electrode, the electrode terminal 140 may correspond to a positive electrode terminal, and vice versa.

[0061] The electrode terminal 140 may be riveted to the through-hole 113 of the cell casing 110. The electrode terminal 140 may be coupled to the upper plate 112 by riveting while being fitted into the through-hole 113 of the upper plate 112. The electrode terminal 140 may be riveted to the upper plate 112 of the cell casing 110. The electrode terminal 140 may have an overall rivet shape.

[0062] The electrode terminal 140 may include a first portion 141 disposed above the upper plate 112, a second portion 142 extending downward from the first portion 141 and passing through the through hole 113, and a third portion 143 extending from the second portion 142 and disposed below the upper plate 112. The first portion 141 may be disposed outside the cell casing 110, and the third portion 143 may be disposed in the accommodation space of the cell casing 110. The third portion 143 may be deformed by pressure and have a shape that extends radially outward from the cell casing 110. The upper plate 112 may be disposed between the first portion 141 and the third portion 143. An outer diameter D2 of the first portion 141 and an outer diameter of the third portion 143 may be larger than the diameter of the through hole 113, and an outer diameter of the second portion 142 may be smaller than the diameter of the through hole 113. The outer diameter D2 of the first portion 141 may be smaller than the outer diameter D1 of the cell casing 110. The outer diameter D2 of the first portion 141 may be set in consideration of a welding space with a bus bar connected to the first portion 141.

[0063] The electrode terminal 140 may have a coupling groove 145 formed at a bottom portion thereof. The coupling groove 145 may be formed at a lower portion of the electrode terminal 140 facing the electrode assembly 120. The coupling groove 145 may include a groove formed at the second portion 142. Because the electrode terminal 140 has the coupling groove 145 formed at its bottom portion, a thickness T1 of the electrode terminal 140 at a welding portion WA to be welded to the connecting terminal 133 may be thinner than the surrounding area.

[0064] At least a portion of the connecting terminal 133 of the first current collector 131 may be inserted into the coupling groove 145. The protrusion 133b of the connecting terminal 133 may be inserted into the coupling groove 145 of the electrode terminal 140. The coupling groove 145 may have a shape corresponding to the protrusion 133b of the connecting terminal 133. For example, if the protrusion 133b has a cylindrical shape, the coupling groove 145 may have a circular cross section. The outer diameter D3 of the protrusion 133b of the coupling groove 145 may correspond to or have a similar value to the diameter of the coupling groove 145. If the outer diameter D3 of the protrusion 133b is slightly smaller than the diameter of the coupling groove 145, the protrusion 133b can be easily fitted into the coupling groove 145. The outer diameter D3 of the protrusion 133b may be smaller than the diameter of the through-hole 113. The shape of the coupling groove 145 and the protrusion 133b is not limited to a circular cross section, but may also have an angular and / or arcuate cross section.

[0065] The battery cell 100 according to an embodiment may further include a first gasket 161 disposed between the electrode terminal 140 and the through-hole 113 and having electrical insulation properties.

[0066] The first gasket 161 may be disposed between the electrode terminal 140 and the upper plate 112 to insulate the electrode terminal 140 from the upper plate 112. The first gasket 161 may include an electrically insulating material. The first gasket 161 may serve as a sealing member that seals the gap between the electrode terminal 140 and the upper plate 112.

[0067] The electrode terminal 140 may be inserted into the through-hole 113 from the outside of the upper plate 112. Because the outer diameter D2 of the electrode terminal 140 is larger than the diameter of the through-hole 113, the first portion 141 of the electrode terminal 140 can be disposed outside the upper plate 112. The third portion 143 is deformed by riveting, thereby fixing the electrode terminal 140 to the upper plate 112.

[0068] When riveting is performed with the first gasket 161 disposed on the outer side of the electrode terminal 140, the first gasket 161 can be disposed between the electrode terminal 140 and the upper plate 112. The first gasket 161 can seal and / or insulate the electrode terminal 140 and the upper plate 112.

[0069] The electrode assembly 120 may be disposed in the receiving space of the cell case 110. The electrode assembly 120 may include a positive electrode, a negative electrode, and a separator 123. The positive electrode and the negative electrode may each include a current collecting foil (or metal foil) and a mixture layer coated on at least one surface of the current collecting foil. The mixture layer may include an active material. The separator 123 may be interposed between the positive electrode and the negative electrode to electrically insulate the positive electrode and the negative electrode. The electrode assembly 120 may be formed by repeatedly arranging the positive electrode, the negative electrode, and the separator 123. For example, the electrode assembly 120 may have a winding shape in which the positive electrode, the separator 123, and the negative electrode are stacked and wound. However, the electrode assembly 120 is not limited to a winding structure. For example, the electrode assembly 120 may have a stacking shape, a zigzag-folding shape, or a stack-folding shape.

[0070] The electrode assembly 120 may include a first electrode 121 and a second electrode 122 having opposite polarities. For example, the first electrode 121 may be provided as a positive electrode and the second electrode 122 may be provided as a negative electrode, or vice versa.

[0071] The electrode assembly 120 may include a body 120a in which a first electrode 121 and a second electrode 122 are arranged with a separator 123 sandwiched therebetween, and an electrode tab 120b extending from the first electrode 121 or the second electrode 122. The body 120a may include a coated portion to which an active material is applied, and the electrode tab 120b may include a non-coated portion to which no active material is applied. The electrode tabs 120b may have a shape that overlaps or lies side by side in a certain pattern.

[0072] The electrode tabs 120b may include a first electrode tab 121a extending from the first electrode 121 and a second electrode tab 122a extending from the second electrode 122. The first electrode tab 121a may include an uncoated portion of the first electrode 121, and the second electrode tab 122a may include an uncoated portion of the second electrode 122.

[0073] The electrode tab 120b may be electrically connected to the current collector 130. The current collector 130 may include a first current collector 131 and a second current collector 135. The first electrode tab 121a may be electrically connected to the first current collector 131. For example, the first electrode tab 121a and the first current collector 131 may be electrically connected to each other by welding or the like. The second electrode tab 122a may be electrically connected to at least one of the second current collector 135, the cap plate 150, or the side wall 111 of the cell casing 110. For example, the second electrode tab 122a and the second current collector 135 may be electrically connected to each other by contact, or may be connected to each other by welding such as ultrasonic welding or laser welding. However, the method of connecting the second electrode tab 122a and the second current collector 135 is not limited thereto.

[0074] The first current collector 131 may electrically connect the electrode terminal 140 and the electrode assembly 120 .

[0075] The first current collector 131 may be electrically connected to the first electrode tab 121a of the electrode assembly 120 at a lower side and to the electrode terminal 140 at an upper side. For example, the first current collector 131 and the first electrode tab 121a may be joined to each other by welding such as ultrasonic welding, laser welding, or resistance welding, but the joining method is not limited thereto. The first current collector 131 and the electrode terminal 140 may be joined to each other by welding such as laser welding.

[0076] The first current collector 131 may include a connecting terminal 133 having a protrusion 133b that fits into the coupling groove 145 of the electrode terminal 140. The protrusion 133b of the connecting terminal 133 may be inserted into the coupling groove 145 formed in the lower part of the electrode terminal 140.

[0077] The protrusion 133b of the connecting terminal 133 may have a cylindrical shape with a circular cross section. The protrusion 133b of the connecting terminal 133 and the coupling groove 145 of the electrode terminal 140 may have corresponding shapes. For example, if the protrusion 133b has a cylindrical shape, the coupling groove 145 may have a circular cross section. To facilitate fitting of the protrusion 133b into the coupling groove 145, the outer diameter D3 of the protrusion 133b may be slightly smaller than the diameter of the coupling groove 145. The outer diameter D3 of the protrusion 133b may be smaller than the diameter of the through hole 113. The shapes of the coupling groove 145 and the protrusion 133b are not limited to a circular cross section. Furthermore, the diameter of the coupling groove 145, the outer diameter D3 of the protrusion 133b, and the diameter of the through hole 113 may be variously modified. For example, the side surface 133c of the protrusion 133b may be formed as a plane perpendicular to the welding direction. Alternatively, at least a portion of the side surface 133c of the protrusion 133b may include an inclined surface (see FIGS. 5 and 6).

[0078] The first current collector 131 may further include a current collecting plate 132 electrically connected to the first electrode tab 121a of the electrode assembly 120. The current collecting plate 132 may be connected to a connection terminal 133. That is, the first current collector 131 may include the current collecting plate 132 electrically connected to the first electrode tab 121a and the connection terminal 133 connected to the current collecting plate 132.

[0079] The current collecting plate 132 of the first current collector 131 may be welded to the first electrode tab 121a. The current collecting plate 132 may be welded to the first electrode tab 121a by laser welding, ultrasonic welding, resistance welding, or the like while being disposed so as to contact the first electrode tab 121a.

[0080] The connecting terminal 133 may include a protrusion 133b that fits into the coupling groove 145 of the electrode terminal 140. The connecting terminal 133 may further include a support 133a that is coupled to the current collecting plate 132. That is, the connecting terminal 133 may include the support 133a that is coupled to the current collecting plate 132, and the protrusion 133b that extends upward from the support 133a and is inserted into the coupling groove 145 of the electrode terminal 140. The support 133a and the protrusion 133b may be integrally formed. The support 133a and the protrusion 133b may be integrally manufactured by forging, pressing, or the like.

[0081] The protrusion 133b of the connecting terminal 133 may extend from the support portion 133a and have a shape that passes through the opening 132a formed in the current collecting plate 132. The connecting terminal 133 may be coupled to the current collecting plate 132 in a state where the protrusion 133b is disposed to pass through the opening 132a of the current collecting plate 132. The outer diameter D4 of the support portion 133a may be greater than the diameter of the opening 132a and the outer diameter D3 of the protrusion 133b.

[0082] The current collecting plate 132 and the connecting terminal 133 may be manufactured separately and then coupled to each other. The current collecting plate 132 has a relatively thin plate shape compared to the connecting terminal 133, and the connecting terminal 133 has a relatively thick cylindrical shape compared to the current collecting plate 132. Therefore, when the current collecting plate 132 and the connecting terminal 133 are manufactured separately, their manufacture may be simplified and design flexibility for the thickness T2 of the connecting terminal 133 may be improved. The connecting terminal 133 and the current collecting plate 132 may be joined by welding. However, the joining method between the connecting terminal 133 and the current collecting plate 132 is not limited to this, and other joining methods such as fitting may also be applied. Meanwhile, in the present disclosure, the current collecting plate 132 and the connecting terminal 133 are not limited to a separate structure and may also have an integrated structure (see FIGS. 7 to 8c).

[0083] The connecting terminal 133 of the first current collector 131 may be coupled to the electrode terminal 140 by welding. The connecting terminal 133 may be coupled to the electrode terminal 140 by welding from the outside of the cell casing 110 with the protrusion 133b fitted into the coupling groove 145. The electrode terminal 140 and the connecting terminal 133 of the first current collector 131 may be joined to each other and electrically coupled to each other by laser welding. The direction in which the laser is irradiated during laser welding may be perpendicular to the upper plate 112. A portion where the electrode terminal 140 and the protrusion 133b of the connecting terminal 133 abut against each other in the laser irradiation direction may form a welded portion WA. The welded portion WA may be defined as a portion where the electrode terminal 140 and the protrusion 133b abut against each other and are coupled by welding.

[0084] According to one embodiment, the protrusion 133b of the connecting terminal 133 is inserted into the coupling groove 145 formed at the bottom of the electrode terminal 140, and the electrode terminal 140 can be electrically connected to the connecting terminal 133 of the first current collector 131 by welding outside the cell casing 110. This can prevent welding foreign matter (e.g., foreign matter such as fumes and spatters) from being generated inside the battery cell 100. In addition, because metal foreign matter such as fumes and spatters is not generated inside the cell casing 110, dust collection from inside the casing is not required during welding, thereby reducing the cost of installing dust collection equipment.

[0085] When irradiating the outside of the cell casing 110 with a laser, the laser may be irradiated onto the outer surface of the electrode terminal 140. That is, the laser may be irradiated onto the surface of the first portion 141 of the electrode terminal 140. In this case, the surface of the first portion 141 irradiated with the laser may be flat. When the surface of the first portion 141 is flat, uniform welding may be performed between the first portion 141 of the electrode terminal 140 and the protrusion 133b of the connecting terminal 133.

[0086] In this disclosure, the welding method between the electrode terminal 140 and the connecting terminal 133 is exemplified as laser welding, but the welding method between the two is not limited to this, and other welding methods such as ultrasonic welding and resistance welding can also be applied.

[0087] The thickness T2 of the connecting terminal 133 at the welded portion WA between the protrusion 133b and the electrode terminal 140 may be equal to or greater than the thickness T1 of the electrode terminal 140. That is, based on the joining direction (or welding direction) of the electrode terminal 140 and the connecting terminal 133, the thickness T1 of the electrode terminal 140 at the welded portion WA between the electrode terminal 140 and the connecting terminal 133 may be equal to or smaller than the thickness T2 of the connecting terminal 133. The thickness T2 of the connecting terminal 133 may be defined as the combined thickness of the protrusion 133b and the supporting portion 133a. The thickness T2 of the connecting terminal 133 may also be defined as the thickness of the thickest portion of the welded portion WA of the connecting terminal 133 based on the welding direction (Z-axis direction).

[0088] Since the thickness T1 of the electrode terminal 140 at the welded portion WA is relatively small, the penetration depth of the laser can be small when a laser is irradiated from the outside of the cell casing 110 toward the electrode terminal 140. This reduces the energy required for laser welding. According to the embodiment, since less energy is required during laser welding, damage to the electrode assembly 120 due to welding heat can be reduced.

[0089] The thickness T2 of the connecting terminal 133 at the welded portion WA is equal to or greater than the thickness T1 of the electrode terminal 140, thereby reducing the effect of heat generated during laser welding on the electrode assembly 120. If the thickness T2 of the connecting terminal 133 were thin, the heat transferred to the welded portion WA would be easily transferred to the electrode assembly 120 via the connecting terminal 133, which could easily damage the electrode assembly 120 due to the welding heat. However, according to the embodiment, the thickness T2 of the connecting terminal 133 is equal to or greater than the thickness T1 of the electrode terminal 140, so the heat transferred to the welded portion WA is absorbed and dispersed in the thickness direction of the connecting terminal 133 before being transferred to the electrode assembly 120, thereby preventing or reducing damage to the electrode assembly 120 due to the welding heat.

[0090] In addition, since the thickness T2 of the connecting terminal 133 at the welded portion WA is equal to or greater than the thickness T1 of the electrode terminal 140, it is possible to reduce the thickness T1 of the electrode terminal 140 at the welded portion WA. This reduces the amount of energy required for laser welding, thereby significantly reducing damage to the electrode assembly 120 due to welding heat.

[0091] By reducing the thickness T1 of the electrode terminal 140 at the welded portion WA, the thickness T2 of the connecting terminal 133 can be 1.2 times or more, or 1.5 times or more, the thickness T1 of the electrode terminal 140 in order to reduce welding energy.

[0092] The size and shape of the coupling groove 145 of the electrode terminal 140 and the protrusion 133b inserted therein may be variously modified in order to adjust the penetration depth when welding the electrode terminal 140 and the connecting terminal 133. For example, in order to adjust the penetration depth of welding, the thickness T1 of the electrode terminal 140 at the welded portion WA, the depth, shape and / or structure of the coupling groove 145, and the thickness T2, shape and / or structure of the connecting terminal 133 may be variously modified.

[0093] The protrusion 133b may be provided as a solid type having a filled interior. The connecting terminal 133 may have a solid shape. In this case, the protrusion 133b can fill the coupling groove 145 formed in the electrode terminal 140, thereby improving the rigidity of the electrode terminal 140. According to the embodiment, even when the thickness T1 of the electrode terminal 140 at the welding portion WA is small, the rigidity of the electrode terminal 140 can be ensured by the connecting terminal 133 inserted into the coupling groove 145. Therefore, the thickness T1 of the electrode terminal 140 at the welding portion WA can be reduced, and the amount of energy required for laser welding is reduced, thereby significantly reducing damage to the electrode assembly 120 due to welding heat.

[0094] For example, the thickness T1 of the electrode terminal 140 at the welded portion WA may be 0.5 mm or more and 5 mm or less. The thickness T1 of the electrode terminal 140 at the welded portion WA may be 0.5 mm or more, 1 mm or more, 1.5 mm or more, or 2 mm or more. The thickness T1 of the electrode terminal 140 may be a thickness that allows the shape of the first portion 141 at the welded portion WA to be maintained during laser welding. The thickness T1 of the electrode terminal 140 at the welded portion WA may be 5 mm or less, 4 mm or less, or 3 mm or less. The thickness T2 of the connecting terminal 133 at the welded portion WA may be set to be greater than or equal to the thickness T1 of the electrode terminal 140. For example, the thickness T2 of the connecting terminal 133 at the welded portion WA may be 1.5 mm or more, 2 mm or more, 3 mm or more, 4 mm or more, or 5 mm or more. The thickness T2 of the connecting terminal 133 at the welded portion WA may be 10 mm or less, 8 mm or less, 7 mm or less, 6 mm or less, or 5.5 mm or less.

[0095] To electrically insulate the first current collector 131 from the cell casing 110, an insulating member 163 having electrical insulation properties may be disposed between the first current collector 131 and the cell casing 110. As an example, the insulating member 163 may be disposed between the current collecting plate 132 and the upper plate 112. The shape and position of the insulating member 163 may be changed in various ways.

[0096] The battery cell 100 according to an embodiment may further include a cap plate 150 that covers a bottom side of the receiving space of the cell case 110. The cap plate 150 may be joined to the cell case 110 by crimping or welding.

[0097] The cap plate 150 can cover the receiving space on the side opposite to the electrode terminal 140 .

[0098] The cap plate 150 may be coupled to the side wall 111 of the cell casing 110 by crimping, welding, etc. As an example, a beading process may be performed on the open end 111a of the side wall 111 of the cell casing 110 to form a beading portion P1, and then the end 111a of the side wall 111 and the cap plate 150 may be crimped together to form a crimping portion P2 with the cap plate 150 placed on the beading portion P1. Alternatively, the cap plate 150 may be welded to the end 111a of the side wall 111 (see FIG. 10).

[0099] The cap plate 150 may be formed with a liquid filling hole 152 for injecting an electrolyte into the cell casing 110. The liquid filling hole 152 may be formed in the center of the body 151 of the cap plate 150, but the position and size of the liquid filling hole 152 may be changed in various ways. The liquid filling hole 152 may be sealed with a liquid filling hole plug 153 after the electrolyte is injected.

[0100] A second gasket 162 for sealing may be disposed between the cap plate 150 and the sidewall 111 of the cell casing 110. The second gasket 162 may serve as a sealing member for sealing between the cap plate 150 and the sidewall 111.

[0101] The battery cell 100 according to one embodiment may further include a cap plate 150 covering the bottom side of the receiving space of the cell case 110 and a second current collector 135 electrically connected to the second electrode tab 122a of the electrode assembly 120.

[0102] The upper surface of the second current collector 135 may be configured to be joined to or in contact with the second electrode tab 122a so as to be electrically connected to the second electrode tab 122a. The second current collector 135 and the second electrode tab 122a may be joined by welding. For example, the second current collector 135 and the second electrode tab 122a may be joined by ultrasonic welding, laser welding, resistance welding, etc. Alternatively, the second current collector 135 may not be joined to the second electrode tab 122a, but may be electrically connected to each other while in contact with each other.

[0103] The second current collector 135 may be electrically connected to at least one of the cap plate 150 or the sidewall 111 of the cell casing 110. FIG. 3 illustrates a configuration in which the second current collector 135 is electrically connected to the cap plate 150 and the sidewall 111 of the cell casing 110. In this case, the cap plate 150 and the cell casing 110 may have a second polarity. For example, if the second electrode tab 122a is a negative electrode tab, the cap plate 150 and the cell casing 110 may be negatively charged. The object electrically connected to the second current collector 135 may vary depending on the design specifications of the battery cell 100.

[0104] Alternatively, the second current collector 135 may not be disposed, and the second electrode tab 122a may be directly electrically connected to the cap plate 150 (see FIG. 10).

[0105] 5 and 6 are cross-sectional views showing modified embodiments of the battery cell 100 shown in FIG.

[0106] 1 to 4, the battery cell 100 shown in Figures 5 and 6 differs in the shape of the coupling groove 145 of the electrode terminal 140 and the protrusion 133b of the connecting terminal 133. The description of Figures 1 to 4 excluding the differences can also be applied to Figures 5 and 6.

[0107] 5 and 6, the connecting terminal 133 may include a support portion 133a and a protrusion 133b. The protrusion 133b may be fitted into the coupling groove 145 of the electrode terminal 140.

[0108] The side surface 133c of the protrusion 133b may include an inclined surface, and the inclined surface may have a shape in which the width at the top is narrower than the width at the bottom. For example, the inclined surface may be formed on at least a part of the side surface 133c of the protrusion 133b, and the width of the protrusion 133b formed by the inclined surface may have a shape in which the width narrows toward the top.

[0109] The inclined surface may be formed on the side surface 133c of the protrusion 133b over the entire height of the protrusion 133b, as shown in FIG. 5, or may be formed only on the upper side surface 133c of the protrusion 133b, as shown in FIG. 6.

[0110] Meanwhile, the coupling groove 145 of the electrode terminal 140 may have a shape corresponding to the shape of the protrusion 133b. For example, the coupling groove 145 of the electrode terminal 140 may also have an inclined surface corresponding to the inclined surface formed on the side surface 133c of the protrusion 133b. Alternatively, the coupling groove 145 of the electrode terminal 140 may be formed on a vertical surface as in FIG. 4. In this case, a space may be formed between the inner surface of the coupling groove 145 and the inclined surface of the protrusion 133b.

[0111] When the side surface 133c of the protrusion 133b includes an inclined surface, the protrusion 133b of the first current collector 131 can be easily inserted into the coupling groove 145 of the electrode terminal 140. That is, when the protrusion 133b is fitted into the coupling groove 145, the inclined surface of the protrusion 133b can guide the insertion of the protrusion 133b.

[0112] FIG. 7 is a perspective view showing another embodiment of the first current collector 131. In FIG.

[0113] 7, the first current collector 131 may include a current collecting plate 132 and a connecting terminal 133. The current collecting plate 132 may have a relatively thin plate shape compared to the connecting terminal 133, and the connecting terminal 133 may have a relatively thick cylinder shape compared to the current collecting plate 132.

[0114] The current collecting plate 132 and the connecting terminal 133 may be integrally formed. For example, the first current collector 131 may be formed integrally with the current collecting plate 132 and the connecting terminal 133 by forging or the like. When forging is performed, the current collecting plate 132 having a thin thickness and the connecting terminal 133 having a relatively thick thickness may be integrally formed.

[0115] FIG. 8a is a cross-sectional view showing a state in which the first current collector 131 shown in FIG. 7 is applied to the cross-section of FIG.

[0116] 1 to 4, the battery cell 100 shown in Fig. 8a differs only in that the current collecting plate 132 of the first current collector 131 and the connecting terminal 133 have an integrated structure. The description of Figs. 1 to 4, excluding the difference, can also be applied to Fig. 8a.

[0117] Referring to FIG. 8 a, the current collecting plate 132 of the integrated first current collector 131 is electrically connected to the first electrode tab 121 a, and the connection terminal 133 can be fitted into the coupling groove 145 of the electrode terminal 140 .

[0118] In the embodiment of Fig. 8a, the connecting terminal 133 may correspond to the support portion 133a and the protrusion 133b in Fig. 4. In the embodiment of Fig. 8a, the thickness or height of the connecting terminal 133 may be defined as the total thickness or height of the first current collector 131 at the welding portion WA.

[0119] The protrusion (133b in FIG. 4) of the connecting terminal 133 may be welded to the electrode terminal 140 by welding from the outside of the cell case 110 while being fitted into the coupling groove of the electrode terminal 140.

[0120] 8b and 8c are cross-sectional views showing modified embodiments of the battery cell 100 shown in FIG. 8a.

[0121] Figure 8b shows a state in which the separate type first current collector 131 shown in Figure 5 is replaced with an integrated type first current collector 131, and Figure 8c shows a state in which the separate type first current collector 131 shown in Figure 6 is replaced with an integrated type first current collector 131. Compared to the embodiment of Figure 8a, Figures 8b and 8c differ in that an inclined surface is formed on the side surface 133c of the connecting terminal 133. Except for the differences, the descriptions of Figures 1 to 8a can be applied.

[0122] Referring to Figures 8b and 8c, the current collecting plate 132 of the integrated first current collector 131 is electrically connected to the first electrode tab 121a, and the connection terminal 133 can be welded to the electrode terminal 140 while being fitted into the coupling groove 145 of the electrode terminal 140.

[0123] In the embodiment of Figures 8b and 8c, the connecting terminal 133 may correspond to the support portion 133a and the protrusion 133b in Figures 5 and 6, respectively. In the embodiment of Figures 8b and 8c, the thickness or height of the connecting terminal 133 may be defined as the total thickness or height of the first current collector 131 at the welding portion WA.

[0124] The side surface 133c of the protruding portion (133b in FIGS. 5 and 6) of the connecting terminal 133 may include an inclined surface, and the inclined surface may have a shape in which the width at the top is narrower than that at the bottom.

[0125] The inclined surface may be formed on the side surface 133c of the connecting terminal 133 over the entire height of the connecting terminal 133 as shown in FIG. 8b, or may be formed only on the upper side surface 133c of the connecting terminal 133 as shown in FIG. 8c.

[0126] When the side surface 133c of the connecting terminal 133 includes an inclined surface, the connecting terminal 133 of the first current collector 131 can be easily inserted into the coupling groove 145 of the electrode terminal 140. That is, when the connecting terminal 133 is fitted into the coupling groove 145, the inclined surface of the connecting terminal 133 can guide the insertion of the protrusion 133b.

[0127] FIG. 9 is a cross-sectional view of a battery cell 100 according to another embodiment.

[0128] 1 to 4, the battery cell 100 in Fig. 9 differs only in the structure of the cell case 110. The description of Figs. 1 to 4 can also be applied to the battery cell 100 in Fig. 9, and the differences will be mainly described below.

[0129] 9, the cell case 110 may include a side wall 111 and an upper plate 112. In the embodiment of FIG. 9, the upper plate 112 may be defined as a plate to which the electrode terminal 140 is coupled.

[0130] The side wall 111 may have a tube shape, and the top plate 112 may have a plate shape that covers the top side of the receiving space. The side wall 111 and the top plate 112 may not be integrally formed, but may have a separate structure. In the embodiment of Figure 9, the side wall 111 and the top plate 112 may be joined to each other by welding.

[0131] The cell casing 110 of the present disclosure can be applied not only to cases where the side wall 111 and the top plate 112 have an integral structure, but also to cases where the side wall 111 and the top plate 112 have a separate structure, as in the embodiment shown in Fig. 9. For example, the embodiment of Fig. 9 can be applied to cases where it is difficult to manufacture an integral cell casing 110 by deep drawing due to an increase in the height of the side wall 111, etc.

[0132] FIG. 10 is a cross-sectional view of a battery cell 100 according to yet another embodiment.

[0133] 1 to 4, the battery cell 100 of FIG. 10 differs in the coupling structure between the cap plate 150 and the side wall 111 of the cell case 110. The description of FIGS. 1 to 4 can also be applied to the battery cell 100 of FIG. 9, and the differences will be mainly described below.

[0134] The battery cell 100 shown in FIG. 10 may include a cell case 110, an electrode terminal 140, an electrode assembly 120, and a first current collector 131, and may further include a cap plate 150 covering the bottom side of the accommodating space of the cell case 110.

[0135] The cap plate 150 may cover the receiving space on the side opposite to the electrode terminal 140. The cap plate 150 may be welded to the cell casing 110. The cap plate 150 may be welded to the side wall 111 of the cell casing 110. The cap plate 150 may be welded such that the periphery of the body 151 contacts the end 111a of the side wall 111.

[0136] 10, the cap plate 150 may be electrically connected to the second electrode tab 122a. The cap plate 150 may be electrically connected to the second electrode tab 122a by being joined thereto by welding or the like. Alternatively, the cap plate 150 may be electrically connected to the second electrode tab 122a by applying pressure to the second electrode tab 122a to bring it into contact with the second electrode tab 122a. When the second electrode tab 122a is directly electrically connected to the cap plate 150, the second current collector (135 in FIG. 3) may not be disposed.

[0137] FIG. 11 is a cross-sectional view of a battery cell 100 according to yet another embodiment, FIG. 12 is a cross-sectional view showing the electrode terminal 140 shown in FIG. 11 in a state before riveting, FIG. 13 is a plan view of the electrode terminal 140 shown in FIG. 11, and FIG. 14 is a plan view showing a modified example of the electrode terminal 140 shown in FIG. 13.

[0138] 1 to 10, the battery cell 100 shown in Fig. 11 differs in that a welding groove 146 is formed on the upper surface 141a of the electrode terminal 140. The description of Figs. 1 to 10 excluding this difference can also be applied to Fig. 11.

[0139] 11 to 14, the electrode terminal 140 may have a welding groove 146 formed on an upper portion of the coupling groove 145 for welding between the electrode terminal 140 and the protrusion 133b. The welding groove 146 may be formed in the first portion 141 of the electrode terminal 140 and may have a shape recessed downward from an upper surface 141a of the first portion 141.

[0140] The welding groove 146 may form a welding path for welding. For example, the welding groove 146 may form a path along which a laser is irradiated when laser welding the electrode terminal 140 to the protrusion 133b of the connecting terminal 133. Since welding is performed by irradiating a laser along the welding groove 146, welding of the electrode terminal 140 may be easy.

[0141] The weld groove 146 is recessed into the upper surface 141a of the electrode terminal 140, thereby preventing or minimizing a phenomenon in which a weld bead or a region hardened after melting (W in FIG. 17) protrudes beyond the upper surface 141a of the electrode terminal 140. That is, the weld groove 146 may serve as a space for accommodating molten metal during laser welding. Because the weld groove 146 is formed, no protruding portion may be formed on the upper surface 141a of the electrode terminal 140 after hardening after welding. When electrically connecting the battery cell 100, the electrode terminal 140 may be welded to a bus bar or the like. Because the upper surface 141a of the electrode terminal 140 remains flat even after welding the electrode terminal 140 to the protrusion 133b, a process of electrically connecting the electrode terminal 140 to another battery cell, battery module, or the like can be easily performed.

[0142] The depth of the welding groove 146 may be set so that the molten metal does not protrude beyond the upper surface 141a of the electrode terminal 140 after hardening. For example, if the amount of molten metal is large, the depth of the welding groove 146 may be greater. The cross-sectional shape of the welding groove 146 may include a semicircular groove, an arc-shaped groove, etc. Alternatively, the cross-sectional shape of the welding groove 146 may be a rectangular groove.

[0143] The welding groove 146 can include an open or closed curve shape. The welding groove 146 can include a spiral shape on a plane or can include at least one closed curve. The welding groove 146 can form a welding path of 360 degrees or more.

[0144] For example, as shown in FIG. 13 , the welding groove 146 may have a spiral shape in a plan view when viewed from above. The welding groove 146 may have an open curve shape extending outward from the center. When the welding groove 146 has an open curve shape, such as a spiral shape in a plan view, welding can be completed with only one welding path, thereby improving weldability and / or work speed. The spiral shape of the welding groove 146 may have an angle of 360 degrees or more. For example, the spiral shape of the welding groove 146 may have an angle of 360 degrees or more, 540 degrees or more, or 720 degrees or more. In this case, the welding groove 146 may form an arc-shaped welding path of 360 degrees or more, 540 degrees or more, or 720 degrees or more. The angle of the spiral shape of the welding groove 146 may be set in consideration of the welding area of ​​the electrode terminal. As the angle of the spiral shape of the welding groove 146 increases, the welding path becomes longer, thereby ensuring a stable electrical connection between the electrode terminal 140 and the protrusion 133b.

[0145] Alternatively, the welding groove 146 may include at least one closed curve when viewed from above, as shown in FIG. 14 . For example, the welding groove 146 may include one circular or elliptical shape, in which case the welding groove 146 may form a 360-degree welding path. The welding groove 146 may include two or more circular or elliptical shapes, in which case the welding groove 146 may form an arc-shaped welding path with a total of 720 degrees or more. The number of closed curves of the welding groove 146 may be determined taking into account the welding area of ​​the electrode terminal. As the angle formed by the welding groove 146 increases, the welding path becomes longer, thereby ensuring a stable electrical connection between the electrode terminal 140 and the protrusion 133b.

[0146] The electrode terminal 140 may be riveted to a through-hole (FIG. 113 in FIG. 2) formed in the upper plate 112 of the cell casing 110. Referring to FIG. 12, the electrode terminal 140 before riveting may include a planar first portion 141, a second portion 142 extending downward from the first portion 141, and a third portion 143 extending downward from the second portion 142. A welding groove 146 may be formed in the first portion 141, and a coupling groove 145 may be formed in the second portion 142. The third portion 142 may expand laterally outwardly by riveting. The shape of the electrode terminal 140 shown in FIG. 12, except for the welding groove 146, may also be applied to the electrode terminals 140 of FIGS. 1 to 10.

[0147] On the other hand, the configuration in which the welding groove 146 is formed in the electrode terminal 140 can also be applied to the embodiments of FIGS.

[0148] Fig. 15 is a flowchart showing a method (S100) for manufacturing a battery cell 100 according to one embodiment, and Figs. 16a to 16e are cross-sectional views for explaining the method (S100) for manufacturing the battery cell 100. Figs. 16a to 16e show the method (S100) for manufacturing the battery cell 100 shown in Figs. 1 to 4.

[0149] Referring to Figure 15 together with Figures 1 to 4, a manufacturing method (S100) of a battery cell 100 according to one embodiment includes a step (S110) of riveting an electrode terminal 140 to a through hole 113 formed in an upper plate 112 of a cell case 110 having an open bottom side, a step (S120) of electrically connecting a first current collector 131 to an electrode assembly 120, a step (S130) of inserting the electrode assembly 120 into an accommodating space of the cell case 110, and a welding step (S140) of welding the electrode terminal 140 and the first current collector 131. The first current collector 131 includes a connecting terminal 133 having a protrusion 133b that fits into a coupling groove 145 formed in a bottom portion of the electrode terminal 140, and the welding step (S140) may weld the electrode terminal 140 and the protrusion 133b by applying energy outside the cell casing 110 with the protrusion 133b fitted into the coupling groove 145. A thickness T2 of the connecting terminal 133 at a welded portion WA of the protrusion 133b and the electrode terminal 140 may be equal to or greater than a thickness T1 of the electrode terminal 140.

[0150] 1 to 4, the manufacturing method (S100) of the battery cell 100 will be described. The description of the battery cell 100 described with reference to FIGS. 1 to 14 can also be applied to the manufacturing method (S100) of the battery cell 100.

[0151] 16a, the cell casing 110 includes a side wall 111 and an upper plate 112, and a through-hole 113 may be formed in the upper plate 112. In step S110 of riveting the electrode terminal 140, the electrode terminal 140 may be inserted into the through-hole 113 on the outside of the upper plate 112. A first portion 141 of the electrode terminal 140 may be disposed on the outside of the upper plate 112, and a second portion 142 and a third portion 143 may be inserted into the through-hole 113. The third portion 143 may be deformed radially outward by the riveting process, and the electrode terminal 140 may be fixed to the upper plate 112.

[0152] When riveting is performed with the first gasket 161 disposed on the outer side of the electrode terminal 140, the first gasket 161 can be disposed between the electrode terminal 140 and the upper plate 112. The first gasket 161 can seal and / or insulate the electrode terminal 140 and the upper plate 112.

[0153] The step S120 of electrically connecting the first current collector 131 may include a process of preparing the first current collector 131.

[0154] 16b, the first current collector 131 may include a current collecting plate 132 and a connecting terminal 133. The connecting terminal 133 may include a support portion 133a coupled to the current collecting plate 132 and a protrusion portion 133b extending upward from the support portion 133a. The current collecting plate 132 may electrically connect the first electrode tab 121a of the electrode assembly 120 to the connecting terminal 133.

[0155] The current collecting plate 132 and the connecting terminal 133 may be manufactured separately and then joined by welding. The current collecting plate 132 has a relatively thin plate shape compared to the connecting terminal 133, and the connecting terminal 133 has a relatively thick cylindrical shape compared to the current collecting plate 132. Therefore, when the current collecting plate 132 and the connecting terminal 133 are manufactured separately, manufacturing each of them may be easy.

[0156] The connecting terminal 133 may be coupled to the current collecting plate 132 with the protrusion 133b disposed to pass through the opening (132a in FIG. 2) of the current collecting plate 132. For example, the connecting terminal 133 and the current collecting plate 132 may be joined by welding.

[0157] 7 to 8c, the current collecting plate 132 and the connecting terminal 133 may be integrally formed by forging. When the current collecting plate 132 and the connecting terminal 133 are integrally formed, the process of combining the connecting terminal 133 and the current collecting plate 132 may be omitted, thereby simplifying the assembly process of the battery cell 100.

[0158] 16c, the step of electrically connecting the first current collector 131 to the electrode assembly 120 (S120) may include a process of electrically connecting the first current collector 131 to a first electrode tab 121a of the electrode assembly 120. The first current collector 131 may be welded to the first electrode tab 121a. For example, the first current collector 131 may be ultrasonically welded, laser welded, or resistance welded to the first electrode tab 121a.

[0159] The order of the step S110 of riveting the electrode terminal 140 to the through-hole 113 formed in the upper plate 112 and the step S120 of electrically connecting the first current collector 131 to the electrode assembly 120 may be changed or performed in parallel.

[0160] 16d together with FIG. 4, in the step of inserting the electrode assembly 120 into the receiving space of the cell casing 110 (S130), the electrode assembly 120 may be inserted into the cell casing 110 through the open bottom of the cell casing 110. The electrode assembly 120 may be inserted into the cell casing 110 with the first current collector 131 facing the bottom of the electrode terminal 140. Before the electrode assembly 120 is received in the cell casing 110, the electrode assembly 120 may have the first current collector 131 connected to the first electrode tab 121a, and the cell casing 110 may have the electrode terminal 140 riveted to the upper plate 112. When the electrode assembly 120 is inserted into the cell casing 110, the protrusion 133b of the first current collector 131 may be fitted into a coupling groove 145 formed in the bottom of the electrode terminal 140. An insulating member 163 may be disposed between the upper case and the first current collector 131 .

[0161] 16e together with FIG. 4, the welding step (S140) may weld and electrically connect the electrode terminal 140 and the first current collector 131. In the welding step (S140), energy may be applied outside the cell casing 110 to weld the electrode terminal 140 and the protrusion 133b while the protrusion 133b is fitted into the coupling groove 145. For example, the electrode terminal 140 and the protrusion 133b of the connecting terminal 133 may be coupled by laser welding.

[0162] According to the embodiment, welding is performed outside the cell casing 110, which can prevent welding foreign matter (e.g., foreign matter such as fumes and spatters) from being generated inside the battery cell 100. In addition, because metal foreign matter such as fumes and spatters is not generated inside the cell casing 110, dust collection work for the inside of the casing is not required during welding work, which can reduce the cost of installing dust collection equipment.

[0163] Since the laser is irradiated from the outside of the cell casing 110, a weld bead or a melt-hardened region W may be formed at the portion where the laser is irradiated. The melt-hardened region W may extend from the top of the electrode terminal 140 to the protrusion 133b, thereby physically and electrically connecting the electrode terminal 140 and the protrusion 133b.

[0164] The thickness T2 of the connecting terminal 133 at the welded portion WA between the protrusion 133b and the electrode terminal 140 may be equal to or greater than the thickness T1 of the electrode terminal 140.

[0165] Since the thickness T1 of the electrode terminal 140 at the welded portion WA has a relatively small value, the energy required for laser welding is reduced, and damage to the electrode assembly 120 due to welding heat can be prevented.

[0166] Since the thickness T2 of the connecting terminal 133 at the welded portion WA is equal to or greater than the thickness T1 of the electrode terminal 140, it is possible to reduce the thickness T1 of the electrode terminal 140 at the welded portion WA. This reduces the amount of energy required for laser welding, thereby significantly reducing damage to the electrode assembly 120 due to welding heat.

[0167] The cell casing 110 may include a tube-shaped side wall 111 that forms an accommodating space, and a plate-shaped upper plate 112 that covers the top side of the accommodating space. The side wall 111 and the upper plate 112 may be integrally formed. The cell casing 110 may be manufactured by deep drawing a metal sheet to have the side wall 111 and the upper plate 112 integrally formed. When the cell casing 110 is integrally formed, a process of joining the side wall 111 and the upper plate 112 is not required, which may facilitate manufacturing of the cell casing 110 and / or the battery cell 100 and improve workability.

[0168] 15 , the manufacturing method (S100) of the battery cell 100 according to an embodiment may include the step (S150) of providing a second current collector 135. The second current collector 135 may be electrically connected to the second electrode tab 122a of the electrode assembly 120. The second current collector 135 may be welded to the second electrode tab 122a, or may be electrically connected to the second electrode tab 122a while in contact with the second electrode tab 122a. The step (S150) of disposing the second current collector 135 may be performed before the step (S130) of inserting the electrode assembly 120 into the cell casing 110, or may be performed after the step (S140) of welding the electrode terminal 140 and the first current collector 131. On the other hand, if the second electrode tab 122a and the cap plate 150 are directly electrically connected, the step (S150) of disposing the second current collector 135 may not be performed.

[0169] According to an embodiment, the manufacturing method (S100) of the battery cell 100 may further include the step (S160) of providing a cap plate 150 on the opened bottom side of the cell casing 110. The step (S160) of providing the cap plate 150 may be performed by crimping or welding the cap plate 150 to the cell casing 110. For example, as shown in FIG. 4, the cap plate 150 may be coupled to the end 111a of the side wall 111 through a beading process and a crimping process. Alternatively, as shown in FIG. 10, the cap plate 150 may be coupled to the end 111a of the side wall 111 by welding.

[0170] The manufacturing method (S100) of the battery cell 100 according to an embodiment may further include the step of injecting an electrolyte (S170). The electrolyte may be injected through a filling hole 152 formed in at least one of the cap plate 150, the electrode terminal 140, or the cell casing 110. For example, the electrolyte may be injected into the receiving space of the cell casing 110 through the filling hole 152 formed in the cap plate 150.

[0171] After the step of injecting the electrolyte (S170), a step of sealing the filling hole (S180) may be performed. In the step of sealing the filling hole (S180), the filling hole 152 may be sealed with a filling hole plug 153.

[0172] Thereafter, subsequent processes such as a chemical conversion process may be carried out.

[0173] Meanwhile, the above-described method (S100) for manufacturing the battery cell 100 is merely an example, and the order may be changed depending on the shape or structure of the battery cell 100, some steps may not be performed, or additional steps may be performed in between.

[0174] FIG. 17 is a cross-sectional view illustrating the welding step (S140) for the electrode terminal 140 shown in FIGS.

[0175] 17 together with FIGS. 11 to 14, the electrode terminal 140 may have a welding groove 146 formed on an upper portion of the coupling groove 145 for welding between the electrode terminal 140 and the protrusion 133b. In the welding step (S140), a laser may be irradiated along the welding groove to weld the electrode terminal 140 and the protrusion 133b.

[0176] The welding groove 146 may be formed in the first portion 141 of the electrode terminal 140, and may have a shape recessed downward from the upper surface 141a of the first portion 141. The welding groove 146 may form a path along which a laser is irradiated, thereby facilitating welding of the electrode terminal 140.

[0177] The welding groove 146 is recessed into the upper surface 141a of the electrode terminal 140, thereby preventing or minimizing a phenomenon in which the weld bead or the melted and hardened region W protrudes beyond the upper surface 141a of the electrode terminal 140 in the welding step (S140). Since the upper surface 141a of the electrode terminal 140 remains flat even after welding the electrode terminal 140 to the protrusion 133b, a process of electrically connecting the electrode terminal 140 to another battery cell, battery module, etc. can be easily performed.

[0178] For a detailed description of the welding groove 146, the description of FIGS. 11 to 14 can be applied.

[0179] FIG. 18 is a perspective view of a battery module 200 according to one embodiment.

[0180] Referring to FIG. 18, a battery module 200 according to one embodiment may include a plurality of battery cells 100 and a module housing 210 that houses the plurality of battery cells 100 .

[0181] The battery cells 100 provided in the battery module 200 may be at least one of the battery cells 100 described with reference to FIGS.

[0182] The battery module 200 of the present disclosure is not limited to a specific type when it includes a plurality of battery cells 100. For example, the battery module 200 of the present disclosure is defined to include all of a battery pack, an energy storage device, and the like.

[0183] The module housing 210 may provide a space for accommodating the plurality of battery cells 100. The module housing 210 may include a housing body 211 that forms a space for accommodating the plurality of battery cells 100, and a housing cover 215 that covers the upper sides of the plurality of battery cells 100.

[0184] The above-described content is merely an example of application of the principles of the present disclosure, and other configurations may be included within the scope of the present invention. In addition, some components may be omitted from the above-described embodiments, and each embodiment may be implemented in combination with each other. [Explanation of symbols]

[0185] 100 Battery Cell 110 Cell Case 111 side wall 111a end 112 Upper plate 113 Through hole 120 Electrode assembly 120a Main body 120b electrode tab 121 first electrode 121a First electrode tab 122 Second electrode 122a second electrode tab 123 separation membrane 130 current collector 131 first current collector 132 current collecting plate 132a opening 133 Connection terminal 133a Support part 133b Projection 133c Side 135 Second current collector 140 Electrode terminal 141 First part 141a Upper surface of first part 142 Part 2 143 Part 3 145 Joining groove 146 Welding groove 150 Cap plate 151 Main body 152 Filling port 153 Filling port plug 161 First gasket 162 Second gasket 163 Insulating member 200 Battery module 210 Module Housing

Claims

1. a cell case including a sidewall defining an internal storage space and an upper plate having a through hole; an electrode terminal coupled to the through hole and having a coupling groove formed at a lower portion thereof; an electrode assembly disposed in the receiving space of the cell case; a first current collector electrically connecting the electrode terminal and the electrode assembly, the first current collector includes a connecting terminal having a protrusion that fits into the coupling groove; the protrusion is fitted into the coupling groove and coupled to the electrode terminal by welding from the outside of the cell case, a thickness of the connecting terminal at a welded portion between the protrusion and the electrode terminal that is equal to or greater than a thickness of the electrode terminal;

2. The battery cell according to claim 1 , wherein the protrusion is provided in a solid type with a filled interior.

3. the first current collector further includes a current collecting plate electrically connected to a first electrode tab of the electrode assembly; The battery cell of claim 1 , wherein the current collecting plate is connected to the connection terminal.

4. The connection terminal further includes a support portion coupled to the current collecting plate, The battery cell according to claim 3 , wherein the protrusion extends from the support and has a shape that passes through an opening formed in the current collecting plate.

5. The battery cell of claim 3 , wherein the current collecting plate and the connection terminal are separately manufactured and then coupled to each other or integrally formed.

6. a side surface of the protrusion includes an inclined surface; The battery cell according to claim 1 , wherein the inclined surface has a shape in which the width of the upper side is narrower than that of the lower side.

7. the cell casing has a circular cross-sectional shape; The battery cell according to claim 1 , wherein the through-hole is formed in a center of the top plate.

8. a first gasket disposed between the electrode terminal and the through hole and having electrical insulation properties; The battery cell according to claim 1 , wherein the electrode terminal is riveted to the through-hole of the cell case.

9. The battery cell of claim 1 , wherein the electrode terminal has a welding groove formed on an upper portion of the coupling groove for welding between the electrode terminal and the protrusion.

10. The battery cell of claim 9 , wherein the welding groove comprises a spiral shape on a plane or comprises at least one closed curve.

11. The side wall has a tube shape, and the upper plate has a plate shape that covers an upper side of the storage space, The battery cell of claim 1 , wherein the sidewall and the top plate are integrally formed.

12. The side wall has a tube shape, and the upper plate has a plate shape that covers an upper side of the storage space, The battery cell of claim 1 , wherein the sidewall and the top plate are joined together by welding.

13. The cell case further includes a cap plate that covers a lower side of the receiving space, The battery cell according to claim 1 , wherein the cap plate is joined to the cell casing by crimping or welding.

14. a second current collector electrically connected to a second electrode tab of the electrode assembly; a cap plate covering the lower side of the receiving space of the cell case, The battery cell of claim 1 , wherein the second current collector is electrically connected to at least one of the cap plate or a sidewall of the cell casing.

15. riveting electrode terminals to through holes formed in an upper plate of a cell case having an open bottom; electrically connecting a first current collector to the electrode assembly; inserting the electrode assembly into the receiving space of the cell case; and welding the electrode terminal and the first current collector, the first current collector includes a connecting terminal having a protrusion fitted into a coupling groove formed in a lower portion of the electrode terminal; the welding step applies energy to the outside of the cell casing while the protrusion is fitted into the coupling groove, thereby welding the electrode terminal and the protrusion; a thickness of the connecting terminal at a welding portion between the protrusion and the electrode terminal that is equal to or greater than a thickness of the electrode terminal;

16. the cell case includes a tube-shaped side wall that forms the storage space and a plate-shaped upper plate that covers an upper side of the storage space, The method of claim 15 , wherein the sidewall and the top plate are integrally formed.

17. the first current collector further includes a current collecting plate electrically connecting a first electrode tab of the electrode assembly to the connection terminal; The method of manufacturing a battery cell according to claim 15, wherein the current collecting plate and the connection terminal are separately manufactured and then joined by welding or integrally formed by forging.

18. The electrode terminal has a welding groove formed on an upper portion of the coupling groove for welding the electrode terminal to the protrusion, The method of claim 15 , wherein the welding step includes irradiating a laser along the welding groove to weld the electrode terminal and the protrusion.

19. The method further includes providing a cap plate on the open lower side of the cell casing, The method of manufacturing a battery cell according to claim 15 , wherein the providing the cap plate comprises crimping or welding the cap plate to the cell casing.

20. a plurality of battery cells; a module housing that houses the plurality of battery cells; At least one of the plurality of battery cells a cell case including a sidewall defining an internal storage space and an upper plate having a through hole; an electrode terminal coupled to the through hole and having a coupling groove formed at a lower portion thereof; an electrode assembly disposed in the receiving space of the cell case; a first current collector electrically connecting the electrode terminal and the electrode assembly, the first current collector includes a connecting terminal having a protrusion that fits into the coupling groove; the protrusion is fitted into the coupling groove and is coupled to the electrode terminal by welding from the outside of the cell casing; a thickness of the connecting terminal at a welded portion between the protrusion and the electrode terminal that is equal to or greater than a thickness of the electrode terminal;

Images