Battery cell and method for producing a battery cell

Abstract

The present disclosure relates to a battery cell and a method for manufacturing the battery cell, and aims to provide a battery cell including a cap plate, a terminal, and an insulator that insulates the cap plate from the terminal and is firmly coupled to the terminal and the cap plate, and a method for manufacturing the battery cell. To this end, the present disclosure provides a battery cell comprising: an electrode assembly; a cell case in which the electrode assembly is stored, and in which an opening is formed to allow the electrode assembly to enter the cell case; and a cover plate assembly mounted on the cell case to close the opening, in which the cover plate assembly includes: a cover plate having a first uneven surface in which a plurality of first recesses are formed; a terminal having a second uneven surface in which a plurality of second recesses are formed, the second uneven surface facing the first uneven surface; and a first insulator filling the plurality of first recesses and the plurality of second recesses and interposed between the first uneven surface and the second uneven surface.

Description

Technical Field

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

[0002] Generally, as the demand for portable electronic products (such as laptop computers, video cameras, and mobile phones) has increased rapidly and the formal commercialization of robots, electric vehicles, etc., research on high-performance secondary batteries that can be repeatedly charged and discharged is actively underway.

[0003] Secondary batteries are widely used to drive or store energy in small devices such as portable electronic devices and medium to large devices such as electric vehicles and energy storage systems (ESS). In particular, in the case of medium to large devices, a battery module can be composed of a plurality of prismatic battery cells electrically connected to each other to increase the output and / or capacity of the battery.

[0004] The prismatic battery cell may include a cell case made of a metal material, an electrode assembly accommodated inside the cell case, and a cover plate assembly including a terminal protruding to the outside of the cell case and a cover plate for closing an open side of the cell case.

[0005] The above information disclosed in the technology forming the background of the present disclosure is only intended to enhance the understanding of the background of the present disclosure and may therefore include information that does not constitute related art. Summary of the Invention

[0006] Technical Problem

[0007] The present invention aims to provide a battery cell including a cover plate, a terminal, and an insulator that insulates the cover plate from the terminal and firmly couples to the terminal and the cover plate, and a method for manufacturing the battery cell.

[0008] However, the technical problems to be solved by the present invention are not limited to the above problems, and other problems not mentioned can be clearly understood by those skilled in the art from the explanation of the invention described below.

[0009] Technical Solution

[0010] To solve the above technical problems, a battery cell according to an embodiment of the present invention includes: an electrode assembly; a cell housing in which the electrode assembly is stored and an opening is formed in the cell housing to allow the electrode assembly to enter the cell housing; and a cover assembly mounted on the cell housing to close the opening, wherein the cover assembly includes: a cover having a first uneven surface in which a plurality of first recesses are formed; a terminal having a second uneven surface in which a plurality of second recesses are formed, and the second uneven surface faces the first uneven surface; and a first insulator filling the plurality of first recesses and the plurality of second recesses and interposed between the first uneven surface and the second uneven surface.

[0011] The inner diameter dimension of the entrance of each of the first recesses may be smaller than the maximum inner diameter dimension of the inner diameter dimensions of the portions of the first recesses other than the entrance, and the inner diameter dimension of the entrance of each of the second recesses may be smaller than the maximum inner diameter dimension of the inner diameter dimensions of the portions of the second recesses other than the entrance.

[0012] The first insulator may include: a plurality of first hook protrusions formed by filling the interiors of the plurality of first recesses with molten synthetic resin and curing the synthetic resin; and a plurality of second hook protrusions formed by filling the interiors of the plurality of second recesses with molten synthetic resin and curing the synthetic resin.

[0013] A plurality of micro recesses may be formed in at least one of the first uneven surface and the second uneven surface by laser irradiation, and the first insulator may include a plurality of micro protrusions formed by filling the interiors of the plurality of micro recesses with molten synthetic resin and curing the synthetic resin.

[0014] A first through hole may be formed in the cover, a second through hole aligned with the first through hole may be formed in the terminal, and the cover assembly may further include: a coupling protrusion electrically connected to the terminal through the first through hole and the second through hole; a current collector disposed on a side opposite to the terminal and the cover is between the current collector and the terminal, and the current collector is electrically connected to the coupling protrusion; and a second insulator interposed between the cover and the current collector.

[0015] The cover assembly may further include a gasket covering an inner circumferential surface of the first through hole and elastically and tightly contacting the inner circumferential surface of the first through hole.

[0016] The coupling protrusion and the terminal may be connected by welding.

[0017] The coupling projection may include: a column portion extending from the current collector toward the terminal with a constant diameter; and a joining portion positioned farther from the current collector than the column portion and tapered such that the diameter of the joining portion decreases as the distance from the current collector increases, and the joining portion may be welded to the terminal.

[0018] The second through hole may be tapered such that the size of the inner diameter of the second through hole decreases as the distance from the cover plate increases, and the size of the inclination angle of the tapered joining portion and the size of the inclination angle of the tapered second through hole may be the same.

[0019] The coupling projection may further include an assembly portion between the column portion and the joining portion, the assembly portion being tapered such that the diameter of the assembly portion decreases as the distance from the current collector increases, and the size of the inclination angle of the tapered joining portion is greater than the size of the inclination angle of the tapered assembly portion.

[0020] A pair of terminals may be provided spaced apart from each other along the longitudinal direction of the cover plate, and a pair of insulators may be provided corresponding to the pair of terminals one by one.

[0021] A pair of openings may be provided in the single body housing opening in opposite directions, and a pair of cover plate assemblies may be provided corresponding to the pair of openings one by one.

[0022] A pair of terminals may be provided spaced apart from each other along the longitudinal direction of the cover plate, and a pair of first insulators may be provided corresponding to the pair of terminals one by one.

[0023] According to another aspect of the present invention, there is provided a method for manufacturing a battery cell, the method comprising: manufacturing a cover assembly; inserting an electrode assembly into a cell housing through an opening formed in the cell housing; and mounting the cover assembly on the cell housing to close the opening, wherein manufacturing the cover assembly includes: preparing a cover having a first uneven surface in which a plurality of first recesses are formed; preparing a terminal having a second uneven surface in which a plurality of second recesses are formed; arranging the cover and the terminal by inserting and fixing the cover and the terminal into an injection molding die such that the first uneven surface and the second uneven surface are disposed facing each other inside the injection molding die; molding a first insulator by injecting molten synthetic resin into the injection molding die and curing the synthetic resin, the first insulator filling the plurality of first recesses and the plurality of second recesses and being interposed between the first uneven surface and the second uneven surface; and removing the cover assembly including the cover, the terminal, and the first insulator from the injection molding die.

[0024] The preparing of the cover may include: forming a plurality of first base grooves having a constant inner diameter from an inlet to a bottom in a surface of the cover by stamping; and forming a first undercut by stamping a periphery of the inlet of each of the plurality of first base grooves such that a dimension of the inner diameter of the inlet of each of the plurality of first base grooves is smaller than a dimension of the inner diameter of a portion of each of the plurality of first base grooves other than the inlet.

[0025] The preparing of the terminal may include: forming a plurality of second base grooves having a constant inner diameter from an inlet to a bottom in a surface of the terminal by stamping; and forming a second undercut by stamping a periphery of the inlet of each of the plurality of second base grooves such that a dimension of the inner diameter of the inlet of each of the plurality of second base grooves is smaller than a dimension of the inner diameter of a portion of each of the plurality of second base grooves other than the inlet.

[0026] The manufacturing of the cover assembly may further include forming a plurality of micro-recesses by emitting laser to at least one of the first uneven surface and the second uneven surface, and in the molding of the insulator, the first insulator may be formed to fill the plurality of micro-recesses.

[0027] The manufacturing of the cover assembly may further include: inserting coupling protrusions through the cover and the terminal and welding the coupling protrusions and the terminal; and welding a current collector to the coupling protrusions before welding the coupling protrusions and the terminal.

[0028] In the molding of the insulator, a second insulator may be formed together with the first insulator, the second insulator being disposed spaced apart from the first insulator and the cover plate being between the first insulator and the second insulator.

[0029] The manufacturing of the cover plate assembly may further include mounting a gasket on the cover plate before disposing the cover plate and the terminals, and in the molding of the insulator, the first insulator may be formed to be attached to one side of the gasket, and the second insulator may be formed to be attached to the other side of the gasket.

[0030] Advantageous Effects

[0031] According to an embodiment of the present invention, the first insulator can be firmly coupled to the cover plate and the terminals, and the cover plate assembly including the cover plate, the terminals, and the first insulator can be easily manufactured by an insert injection molding method. Accordingly, the productivity of the battery cell including the cover plate assembly can be improved, and its cost can be reduced.

[0032] In addition, the resistance between the electrode assembly and the terminals can be reduced, thereby reducing the power loss of the battery cell and improving its energy efficiency.

[0033] However, the effects achievable by the present invention are not limited to the above effects, and those skilled in the art can clearly understand other technical effects not mentioned through the following explanation of the present invention. Brief Description of the Drawings

[0034] The drawings attached to this specification illustrate some embodiments of the present disclosure and further describe aspects and features of the present disclosure together with the detailed description of the present disclosure. However, the present disclosure should not be construed as being limited to the drawings:

[0035] Figure 1 is a perspective view of a battery cell according to a first embodiment of the present disclosure;

[0036] Figure 2 is a cross-sectional view taken along line II-II in Figure 1 ;

[0037] Figure 3 is an enlarged cross-sectional view illustrating the cover plate assembly of Figure 2 ;

[0038] Figure 4 is a block diagram illustrating a method for manufacturing a battery cell assembly according to an embodiment of the present disclosure;

[0039] Figure 5 is a block diagram illustrating the operations of manufacturing the cover plate assembly in Figure 4 ;

[0040] Figure 6 is a cross-sectional view for describing Figure 5 the operation of machining the first basic groove or the operation of machining the second basic groove in

[0041] Figure 7 is a cross-sectional view for describing Figure 5 the operation of forming the first undercut or the operation of forming the second undercut in

[0042] Figure 8 is a cross-sectional view for describing Figure 5 the operation of forming a fine recess in

[0043] Figure 9 is a cross-sectional view for describing Figure 5 the operation of joining the connection projection and the current collector in

[0044] Figure 10 is a cross-sectional view for describing Figure 5 the operation of joining the connection projection and the terminal in

[0045] Figure 11 is a perspective view of a battery cell according to a second embodiment of the present disclosure; and

[0046] Figure 12 is a cross-sectional view taken along the line XI-XI in Figure 11 DETAILED DESCRIPTION

[0047] Preferred embodiments of the present invention will be explained in detail below with reference to the accompanying drawings. Before that, terms or words used in the scope of this specification and claims should not be construed in a conventional or dictionary sense, and the inventor must interpret them in a meaning and concept consistent with the technical idea of the present invention based on the principle of being able to appropriately define the terms in order to best explain his own invention. Therefore, since the embodiments described in this specification and the configurations shown in the drawings are only some of the most ideal embodiments of the present invention and do not represent all the technical ideas of the present invention, it is important to understand that there may be various equivalents and variations that can replace them at the time of this application.

[0048] In addition, when used in this specification, "comprising" and / or "including" specify the presence of the recited shapes, quantities, steps, actions, components, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other shapes, quantities, actions, elements, and / or groups.

[0049] In addition, for ease of understanding of the present invention, the drawings may not be shown to actual scale and may exaggerate the dimensions of some components. In addition, the same reference numerals may be assigned to the same components in different embodiments.

[0050] A statement that two comparison targets are "the same" means that they are "substantially the same". Thus, actual equality may include deviations that are considered low in the industry, such as cases with a deviation within 5%. In addition, when a parameter is uniform within a given region, it may mean that it is uniform from an average perspective.

[0051] Although first, second, etc. are used to describe various components, these components are of course not limited by these terms. These terms are only used to distinguish one component from another; of course, unless there is a specific contrary description, the first component may be the second component.

[0052] Throughout the specification, unless specifically stated to the contrary, each component may be singular or plural.

[0053] Placing any configuration "above (or below)" a component or "on (or under)" a component may mean that any configuration is not only arranged to contact the top (or bottom) of the component, but other configurations may also be interposed between the component and any configuration arranged on (or under) the component.

[0054] In addition, when describing that one component is "coupled", "linked", or "connected" to another component, these components may be directly connected or tangent to each other, but it should be understood that other components are "interposed" between each component, and each component may also be "coupled", "linked", or "connected" through other components. In addition, when one part is electrically connected (electrically coupled) to another part, this includes not only the case of direct connection, but also the case where other devices are connected therebetween.

[0055] When using "A and / or B" throughout the specification, this means A, B, or A and B, unless otherwise stated. In other words, "and / or" includes all or any combination of the listed multiple items. When it is "C to D", this means C or higher and D or lower, unless otherwise stated.

[0056] The terms used in this specification are intended to describe embodiments of the present disclosure and are not intended to limit the present disclosure.

[0057] In an exemplary embodiment of a [cylindrical, prismatic, pouch-type] battery according to an embodiment of the present disclosure, the battery selected by choosing one of the prismatic / pouch-type / cylindrical batteries is described as having a general structure, and in the case of common techniques, the general structure of the prismatic / pouch-type / cylindrical battery is described.

[0058] Figure 1 is a perspective view of a battery cell according to a first embodiment of the present invention, Figure 2 is along Figure 1 the cross-sectional view taken along line II-II in Figure 3 is illustrativeFigure 2 An enlarged cross-sectional view of the cover plate assembly. Refer to Figures 1 to 3 , according to an embodiment of the present invention, the battery cell 100 includes a cell case 101, an electrode assembly 110, and a cover plate assembly 120. The battery cell 100 may be a so-called "side-type prismatic battery cell", in which a pair of terminals 140 (i.e., a positive terminal 140 and a negative terminal 140) joined to a bus bar (not illustrated) are provided on one side and the other side of the cell case 101.

[0059] The cell case 101 is made of a metal material (such as aluminum alloy) and may be formed in a substantially rectangular parallelepiped shape. An internal space 102 in which the electrode assembly 110 is stored may be formed inside the cell case 101. A first opening 105 and a second opening 107 that are open in a first direction may be formed on one side and the other side of the cell case 101.

[0060] The electrode assembly 110 may be accommodated inside the cell case 101. The electrode assembly 110 may enter the internal space 102 of the cell case 101 through the first opening 105 or the second opening 107. The electrode assembly 110 may be formed by winding or stacking a stack of a first electrode plate, a separator, and a second electrode plate formed in a thin plate or film shape.

[0061] When the electrode assembly 110 is a wound stack, the winding axis may be parallel to the longitudinal direction of the cell case 101. Additionally, the electrode assembly 110 may be a stacked type rather than a wound type, and the shape of the electrode assembly 110 is not limited in the present invention. Additionally, the electrode assembly 110 may be a Z-type stacked electrode assembly 110, in which a positive electrode plate and a negative electrode plate are inserted on both sides of a separator bent into a Z-type stack. Additionally, the electrode assembly 110 may be stored inside the case, where one or more electrode assemblies 110 are stacked such that their long sides are adjacent to each other, and the number of electrode assemblies 110 is not limited in the present invention. The first electrode plate of the electrode assembly 110 may be used as a negative electrode, and the second electrode plate may be used as a positive electrode. Of course, the reverse is also possible.

[0062] The first electrode plate may be formed by coating a first electrode current collector plate made of a metal foil (such as copper, copper alloy, nickel, or nickel alloy) with a first electrode active material (such as graphite, carbon, etc.), and may include a first electrode tab (or a first uncoated portion) as an area where the first electrode active material is not coated. The first electrode tab may be used as a path for current flow between the first electrode plate and the first current collector. In some examples, the first electrode tab may be pre-formed by cutting the first electrode plate during the manufacture of the first electrode plate such that the first electrode tab protrudes to one side, and may protrude further to one side than the separator without separate cutting.

[0063] The second electrode plate can be formed by coating a second electrode current collector plate made of a metal foil (such as aluminum or aluminum alloy) with a second electrode active material (such as a transition metal oxide, etc.), and can include a second electrode tab (or a second uncoated portion) as an area where the second electrode active material is not coated. The second electrode tab can be used as a path for current flow between the second electrode plate and the second current collector. In some examples, the second electrode tab can be pre-formed by cutting the second electrode plate during the manufacture of the second electrode plate such that the second electrode tab protrudes to the other side, and can protrude further to the other side than the separator without separate cutting.

[0064] In some examples, the first electrode tab can be located on one side of the left end of the electrode assembly 110, and the second electrode tab can be located on one side of the right end of the electrode assembly 100, or on one side in the same direction. Here, "left" and "right" are for convenience of description, and the positions can change when the battery cell 12 rotates left and right or up and down. In some examples, the electrode assembly 110 can be accommodated in a housing together with the electrolyte.

[0065] A pair of cover assemblies 120 can be positioned corresponding to the first opening 105 and the second opening 107 of the cell housing 101. In other words, one cover assembly 120 of the pair of cover assemblies 120 can be mounted on the cell housing 101 to close the first opening 105, and the other cover assembly 120 therein can be mounted on the cell housing 101 to close the second opening 107.

[0066] Each cover assembly 120 includes a cover 121, a terminal 140, and a first insulator 180. The cover 121 closes one of the first opening 105 and the second opening 107. The outer edge of the cover 121 can be welded to the inner surface of one of the first opening 105 and the second opening 107 of the cell housing 101.

[0067] The cover 121 has a first uneven surface 125, and a plurality of first recesses 126 are formed in the first uneven surface 125. The cover 121 can be a plate-like member having a substantially rectangular planar shape and can extend in a second direction perpendicular to the first direction. A cover through-hole 122 passing through the cover 121 in the thickness direction is formed in the cover 121.

[0068] Reference Figures 1 to 3 and Figure 8, the cover plate 121 may include a first side 124 facing the interior of the single cell housing 101 (or in other words, facing the electrode assembly 110) and a second side 125 facing the exterior of the single cell housing 101. A plurality of first recesses 126 and a plurality of micro recesses 132 may be formed on the second side 125. Accordingly, hereinafter, the second side 125 of the cover plate 121 will be referred to as the first uneven surface.

[0069] The inner diameter CI of the inlet 128 of each first recess 126 may be smaller than the maximum inner diameter CH of the inner diameter of the portion of the first recess 26 other than the inlet 128. The size of the inner diameter of the micro recess 132 is smaller than the inner diameter CI of the inlet 128 of the first recess 126.

[0070] The terminal 140 may be made of a conductive metal material. The terminal 140 has a second uneven surface 145 and a plurality of second recesses 146 are formed in the second uneven surface 145. The terminal 140 has a substantially rectangular parallelepiped shape, and a terminal through hole 143 passing through the terminal 140 in the thickness direction (i.e., the first direction) is formed in the terminal 140. The terminal through hole 143 and the cover plate through hole 122 may be aligned along an imaginary straight line parallel to the first direction.

[0071] The terminal 140 may include a first side 145 facing the cover plate 121 and a second side 144 opposite to the first side 145. A bus bar (not illustrated) may be joined to the second side 144. A plurality of second recesses 146 and a plurality of micro recesses 152 may be formed on the first side 145. Accordingly, hereinafter, the first side 145 of the terminal 140 will be referred to as the second uneven surface. The second uneven surface 145 may be arranged to face the first uneven surface 125.

[0072] The inner diameter TI of the inlet 148 of each second recess 146 may be smaller than the maximum inner diameter TH of the inner diameter of the portion of the second recess 146 other than the inlet 148. The size of the inner diameter of the micro recess 152 is smaller than the inner diameter TI of the inlet 148 of the second recess 146.

[0073] The first insulator 180 fills the plurality of first recesses 126 and the plurality of second recesses 146, and is interposed between the first uneven surface 125 and the second uneven surface 145. For example, the first insulator 180 may be made of an insulating material (such as synthetic resin). The first insulator 180 may include a main body 181, a plurality of first hook protrusions 184, a plurality of second hook protrusions 186, and a plurality of micro protrusions 188.

[0074] The body 181 has a thickness corresponding to the gap between the first uneven surface 125 and the second uneven surface 145. The body 181 may include a portion extending in the first direction to cover the outer surface of the terminal 140.

[0075] The plurality of first hook protrusions 184 may be formed by filling the interiors of the plurality of first recesses 126 with molten synthetic resin and curing the synthetic resin. Accordingly, the plurality of first hook protrusions 184 may be firmly joined to the inner surfaces of the plurality of first recesses 126, and the first insulator 180 may be firmly joined to the cover plate 121.

[0076] As described above, when the size of the inner diameter CI of the entrance 128 of the first recess 126 is smaller than the size of the maximum inner diameter CH among the inner diameters of the portions of the first recess 126 other than the entrance 128, since the first undercut 129 is generated around the entrance 128 of the first recess 126, the first hook protrusion 184 cannot be separated from or come out of the first recess 126. Accordingly, the first insulator 180 may be more firmly joined to the cover plate 121.

[0077] The plurality of second hook protrusions 186 may be formed by filling the interiors of the plurality of second recesses 146 with molten synthetic resin and curing the synthetic resin. Accordingly, the plurality of second hook protrusions 186 may be firmly joined to the inner surfaces of the plurality of second recesses 146, and the first insulator 180 may be firmly joined to the terminal 140.

[0078] As described above, when the size of the inner diameter TI of the entrance 148 of the second recess 146 is smaller than the size of the maximum inner diameter TH among the inner diameters of the portions of the second recess 146 other than the entrance 148, since the second undercut 149 is generated around the entrance 148 of the second recess 146, the second hook protrusion 186 cannot be separated from or come out of the second recess 146. Accordingly, the first insulator 180 may be more firmly joined to the terminal 140.

[0079] The plurality of fine protrusions 188 may be formed by filling the interiors of the plurality of fine recesses 132 and 152 with molten synthetic resin and curing the synthetic resin. Accordingly, the plurality of fine protrusions 188 may be firmly joined to the inner surfaces of the plurality of fine recesses 132 and 152, and the first insulator 180 may be more firmly joined to the cover plate 121 and the terminal 140.

[0080] Reference Figures 1 to 3 、 Figure 9 and Figure 10, the cover assembly 120 may further include a coupling projection 160, a current collector 170, a gasket 190, and a second insulator 196. The coupling projection 160 may pass through the cover through-hole 122 and the terminal through-hole 143 and be electrically connected to the terminal 140. The coupling projection 160 may be made of a conductive metal material.

[0081] The current collector 170 may be disposed on a side opposite to the terminal 140 with the cover 121 therebetween, and the current collector 170 may be electrically connected to the coupling projection 160. The current collector 170 may be made of a conductive metal material. The current collector 170 is a plate-like member having a substantially square planar shape and may extend in a second direction.

[0082] The coupling projection 160 may extend along a first direction. The coupling projection 160 may include a joining portion 162, an assembling portion 164, a column portion 166, and a flange portion 168. The column portion 166 extends in a direction from the current collector 170 toward the terminal 140. The dimension of the diameter of the column portion 166 is constant along the first direction.

[0083] The joining portion 162 is positioned farther from the current collector 170 than the column portion 166. The joining portion 162 is tapered such that its diameter becomes smaller as the distance from the current collector 170 increases. For example, the joining portion 162 may be connected to the terminal 140 by welding (such as laser welding).

[0084] The assembling portion 164 is located between the column portion 166 and the joining portion 162. The assembling portion 164 is tapered such that its diameter becomes smaller as the distance from the current collector 170 increases. The flange portion 168 protrudes from the outer peripheral surface of the column portion 166 in a radial direction perpendicular to the first direction. The flange portion 168 protrudes stepwise from the column portion 166, and the diameter of the flange portion 168 is larger than the diameter of the column portion 166.

[0085] The terminal through-hole 143 of the terminal 140 may be tapered such that the dimension of its inner diameter becomes smaller as the distance from the cover 121 increases to correspond to the joining portion 162. The dimension of the inclination angle AR1 of the tapered joining portion 162 and the dimension of the inclination angle AT of the tapered terminal through-hole 143 may be the same.

[0086] When the joining portion 162 is aligned with the cover through-hole 122 and the terminal through-hole 143 and inserted into the terminal through-hole 143 through the cover through-hole 22, the outer peripheral surface of the joining portion 162 and the inner peripheral surface of the terminal through-hole 143 are in surface contact, and the joining portion 162 may not cross over the terminal through-hole 143. In this way, the welding of the coupling projection 160 and the terminal 140 may be made easier due to the tapered joining portion 162 and the tapered terminal through-hole 143.

[0087] The dimension of the inclination angle AR1 of the conical joint portion 162 can be larger than the dimension of the inclination angle AR2 of the conical assembly portion 164. In other words, the dimension of the inclination angle AR2 of the assembly portion 164 can be smaller than the dimension of the inclination angle AR1 of the joint portion 162. For example, the inclination angle AR1 of the joint portion 162 can be 8° to 10°, and the inclination angle AR2 of the assembly portion 164 can be 6° to 7°.

[0088] When the dimension of the inclination angle AR2 of the assembly portion 164 is larger than the dimension of the inclination angle AR1 of the joint portion 162, the outer peripheral surface of the joint portion 162 does not make surface contact with the inner peripheral surface of the terminal through-hole 143. In addition, when the dimension of the inclination angle AR2 of the assembly portion 164 is the same as the dimension of the inclination angle AR1 of the joint portion 162, even if there are slight machining errors, the outer peripheral surface of the joint portion 162 does not make surface contact with the inner peripheral surface of the terminal through-hole 143.

[0089] When a laser beam is emitted along the edge of the outer peripheral surface of the joint portion 162 and the edge of the inner peripheral surface of the terminal through-hole 143 of the terminal 140 in a state where the joint portion 162 makes surface contact with the inner peripheral surface of the terminal through-hole 143, an annular weld portion 158 can be formed, and thus the coupling projection 160 and the terminal 140 can be welded.

[0090] A current collector through-hole 174 penetrating the current collector 170 in the thickness direction is formed in the current collector 170. The dimension of the inner diameter of the current collector through-hole 174 is larger than or equal to the diameter of the column portion 166 of the coupling projection 160 and smaller than the diameter of the flange portion 168. The current collector 170 has a side 171 facing the electrode assembly 110 and another side 172 that is opposite to the side 171 and faces the cover plate 121.

[0091] An annular groove 176 is formed in a stepped annular shape on the side 171 of the current collector 170 to place the flange portion 168. When the coupling projection 160 is inserted into the current collector through-hole 174 such that the flange portion 168 of the coupling projection 160 is placed in the annular groove 176 and a laser beam is emitted along the edge of the outer peripheral surface of the flange portion 168 and the edge of the inner peripheral surface of the annular groove 176, an annular weld portion 178 can be formed, and thus the coupling projection 160 and the current collector 170 can be welded.

[0092] Reference Figures 1 to 3, the gasket 190 may cover the inner circumferential surface 123 of the cover plate through hole 122 and may be in elastic close contact with the inner circumferential surface 123 of the cover plate through hole 122. The gasket 190 may be made of an elastic material having insulating properties. The gasket 190 may include a tubular gasket tube portion 191 extending in a first direction and a gasket flange portion 194 extending in a radial direction to increase the diameter of the gasket tube portion 91.

[0093] One end of the gasket tube portion 191 may be attached to the second insulator 196, and the other end may be connected to the gasket flange portion 194. The outer circumferential surface of the gasket flange portion 194 may be in close contact with the main body 181 of the first insulator 180.

[0094] One side of the gasket flange portion 194 may be in close contact with the portion of the first uneven surface 125 not covered by the first insulator 180, and the other side of the gasket flange portion 194 may be in close contact with the portion of the second uneven surface 145 not covered by the first insulator 180. The end of the gasket flange portion 194 farthest from the coupling projection 160 may be attached to the first insulator 180.

[0095] The second insulator 196 is interposed between the cover plate 121 and the current collector 170 to insulate the cover plate 121 and the current collector 170. For example, the second insulator 196 may be made of an insulating material (such as synthetic resin).

[0096] The current collector 170 included in the cover plate assembly 120 closing the first opening 105 may be electrically connected to the uncoated portion of one of the first electrode plate and the second electrode plate of the electrode assembly 110, and the current collector 170 included in the cover plate assembly 120 closing the second opening 107 may be electrically connected to the uncoated portion of the other of the first electrode plate and the second electrode plate of the electrode assembly 110.

[0097] The current collector 170 may be directly electrically connected to the uncoated portion by a method such as welding, or may be electrically connected to the uncoated portion via a sub-board (not illustrated).

[0098] Figure 4 is a block diagram illustrating a method for manufacturing a battery cell assembly according to an embodiment of the present disclosure, Figure 5 is an illustration of manufacturing Figure 4 The operation of the cover plate assembly in Figure 6 is for describing Figure 5 The cross-sectional view of the operation of processing the first base groove or the operation of processing the second base groove in Figure 7 is for describing Figure 5 The cross-sectional view of the operation of forming the first undercut or the operation of forming the second undercut in Figure 8 is for describing Figure 5A cross-sectional view of the operation of forming a fine indentation therein Figure 9 is for describing Figure 5 the operation of joining the coupling protrusion and the current collector in Figure 10 and is for describing Figure 5 the operation of joining the coupling protrusion and the terminal in

[0099] Referring to Figures 1 to 10 according to an embodiment of the present invention, a method for manufacturing a battery cell includes an operation of manufacturing a cover plate assembly (S100), an operation of inserting an electrode assembly into a cell case (S200), and an operation of installing the cover plate assembly (S300).

[0100] As an operation of manufacturing the cover plate assembly 120, the operation of manufacturing the cover plate assembly (S100) includes an operation of preparing a cover plate (S110), an operation of preparing a terminal (S120), an operation of arranging the cover plate and the terminal (S150), an operation of molding an insulator (S160), and an operation of removing the cover plate assembly (S170).

[0101] The operation of preparing the cover plate (S110) is an operation of preparing a cover plate 121 having a first uneven surface 125, in which a plurality of first indentations 126 are formed. The operation of preparing the cover plate (S110) may include an operation of machining a first base groove (S111) and an operation of forming a first undercut (S112) to form a plurality of first indentations 126.

[0102] Referring to Figure 6 the operation of machining the first base groove (S111) is an operation of forming a plurality of first base grooves 126B having a constant inner diameter from an inlet to a bottom in the surface (specifically, the first uneven surface 125) of the cover plate 121 by stamping. For example, a stamping die equipped with a plurality of first punches 501 having a substantially cylindrical shape may be used to machine the plurality of first base grooves 126B.

[0103] Referring to Figures 6 to 8 the operation of forming the first undercut (S112) is an operation of forming a first undercut 129 by stamping the periphery of the inlet of each of the plurality of first base grooves 126B such that the inner diameter dimension of the inlet of each of the plurality of first base grooves 126B is smaller than the inner diameter dimension of the portion of each of the plurality of first base grooves 126B other than the inlet.

[0104] By the operation of forming the first undercut (S112), a first indentation 126 can be formed, in which the inner diameter CI of the inlet 128 is smaller than the inner diameter CH of the portion other than the inlet 128.

[0105] The first undercut 129 can be formed by stamping. For example, the first undercut 129 can be formed by stamping the periphery of the entrance of the first base groove 126B using a stamping die equipped with a plurality of tubular second punches 505, each of the plurality of tubular second punches 505 having an inner diameter slightly larger than the diameter of the cylindrical first punch 501. Since the end of each second punch 505 stamps the first uneven surface 125, an annular groove 130 can be formed in the first uneven surface 125.

[0106] Reference Figures 3 to 10 , the operation of preparing the terminal (S120) is an operation of preparing a terminal 140 having a second uneven surface 145, in which a plurality of second recesses 146 are formed. The operation of preparing the terminal (S120) may include an operation of machining a second base groove (S121) and an operation of forming a second undercut (S122) to form a plurality of second recesses 146.

[0107] Reference Figure 6 , the operation of machining the second base groove (S121) is an operation of forming a plurality of second base grooves 146B having a constant inner diameter from the entrance to the bottom in the surface of the terminal 141 (specifically, the second uneven surface 145) by stamping. For example, a plurality of second base grooves 146B can be machined using a stamping die equipped with a plurality of first punches 501 having a substantially cylindrical shape.

[0108] Reference Figures 6 to 8 , the operation of forming the second undercut (S122) is an operation of forming a second undercut 149 by stamping the periphery of the entrance of each of the plurality of second base grooves 146B such that the inner diameter dimension of the entrance of each of the plurality of second base grooves 146B is smaller than the inner diameter dimension of the portion of each of the plurality of second base grooves 146B other than the entrance.

[0109] By the operation of forming the second undercut (S122), a second recess 146 can be formed, in which the inner diameter TI of the entrance 148 is smaller than the inner diameter TH of the portion other than the entrance 148.

[0110] The second undercut 149 can be formed by stamping. For example, the second undercut 149 can be formed by stamping the periphery of the entrance of the second base groove 146B using a stamping die equipped with a plurality of tubular second punches 505, each of the plurality of tubular second punches 505 having an inner diameter slightly larger than the diameter of the cylindrical first punch 501. Since the end of each of the second punches 505 stamps the second uneven surface 145, an annular groove 150 can be formed in the second uneven surface 145.

[0111] The operation of manufacturing the cover plate assembly (S100) may further include an operation of forming micro recesses (S130). The operation of forming micro recesses (S130) is an operation of forming a plurality of micro recesses 132 and 152 as shown by emitting a laser beam to at least one of the first uneven surface 125 and the second uneven surface 145 Figure 8 The operation of arranging the cover plate and the terminal (S150) is an operation of inserting and fixing the cover plate 121 and the terminal 140 into an injection molding die (not illustrated) such that the first uneven surface 125 and the second uneven surface 145 are arranged to face each other inside the injection molding die.

[0112] More specifically, the injection molding die includes an upper molding die and a lower molding die, and a cavity is formed between them when the upper molding die and the lower molding die are in close contact. When the upper molding die and the lower molding die of the injection molding die are spaced apart, the cover plate 121 and the terminal 140 are mounted on the upper molding die or the lower molding die, and when the upper molding die and the lower molding die are in close contact, the cover plate 121 and the terminal 140 can be inserted and fixed inside the injection molding die.

[0113] Referring to

[0114] The operation of molding the insulator (S160) is an operation of forming a first insulator 180 that fills a plurality of first recesses 126 and a plurality of second recesses 146 and is located between the first uneven surface 125 and the second uneven surface 145 by injecting molten synthetic resin into the injection molding die and curing the synthetic resin. Figures 3 to 10 In the operation of molding the insulator (S160), a plurality of first hook protrusions 184 and a plurality of second hook protrusions 186 may be formed. In addition, by filling the plurality of micro recesses 132 and 152 with synthetic resin and curing the synthetic resin, a plurality of micro protrusions 188 may be formed.

[0115] The operation of removing the cover plate assembly (S170) is an operation of removing the cover plate assembly 120 including the cover plate 121, the terminal 140, and the first insulator 180 from the injection molding die. The upper molding die and the lower molding die of the injection molding die may be separated, and the cover plate assembly 120 may be separated and removed from the injection molding die.

[0116] The operation of manufacturing the cover plate assembly (S100) may further include an operation of installing a gasket (S140), an operation of welding the coupling protrusion and the current collector (S180), and an operation of welding the coupling protrusion and the terminal (S190).

[0117]

[0118] ​The operation of installing the gasket (S140) is an operation of installing the gasket 190 on the cover plate 121 before the operations of placing the cover plate and the terminals (S150). For example, the gasket 190 may be installed on the cover plate 121 such that the gasket 190 covers the inner circumferential surface 123 of the cover plate through-hole 122 and is in elastic close contact with the inner circumferential surface of the cover plate through-hole 122. Since the configuration and functions of the gasket 190 have been described with reference to Figure 3 , redundant descriptions will be omitted.

[0119] Meanwhile, the shape of the cavity formed by the close contact between the upper molding die and the lower molding die of the injection molding die may correspond to the combined shape of the cover plate 121, the terminals 140, the first insulator 180, the second insulator 196, and the gasket 190.

[0120] In this case, when injecting and curing the molten synthetic resin into the inside of the injection molding die during the operation of molding the insulator (S160), the second insulator 196 may be formed together with the first insulator 180. The second insulator 196 is arranged to be spaced apart from the first insulator 180, and the cover plate 121 is therebetween.

[0121] The first insulator 180 and the second insulator 196 may be formed to be spaced apart, and the gasket 190 is therebetween. The first insulator 180 may be formed to be attached to one side of the gasket 190, and the second insulator 196 may be formed to be attached to the other side of the gasket 190. For example, the first insulator 180 may be attached to the lower end of the gasket tube portion 191 included in the gasket 190.

[0122] The second insulator 196 may be attached to the end of the gasket flange portion 194 included in the gasket 190. The second insulator 196 may be formed to be attached to the side 124 of the cover plate 121 facing the electrode assembly 110. Since the temperature of the molten synthetic resin is lower than the melting temperature of the gasket 190, the gasket 190 does not melt inside the injection molding die.

[0123] Referring to Figure 3 , Figure 5 and Figure 9 , the operation of welding the connection projection and the current collector (S180) is an operation of welding the current collector 170 to the connection projection 160 before the operation of welding the connection projection and the terminals (S190). More specifically, when the connection projection 160 is inserted into the current collector through-hole 174 such that the flange portion 168 of the connection projection 160 is placed in the annular groove 176 and a laser beam is emitted along the edge of the outer circumferential surface of the flange portion 168 and the edge of the inner circumferential surface of the annular groove 176, an annular welded portion 178 may be formed, thereby welding the connection projection 160 and the current collector 170.

[0124] Referring toFigure 3 , Figure 5 and Figure 10 , the operation (S190) of welding the connection projection and the terminal is an operation of inserting the connection projection 160 through the cover plate 121 and the terminal 140 and welding the connection projection 160 and the terminal 140. More specifically, the connection projection 160 joined to the current collector 170 is inserted into the cover plate through-hole 122 with the joining portion 162 as the head, so that the joining portion 162 makes surface contact with the inner peripheral surface of the terminal through-hole 143.

[0125] In this way, when a laser beam is emitted along the edge of the outer peripheral surface of the joining portion 162 and the edge of the inner peripheral surface of the terminal through-hole 143 of the terminal 140 in a state where the joining portion 162 makes surface contact with the inner peripheral surface of the terminal through-hole 143, an annular welded portion 158 can be formed, thereby welding the connection projection 160 and the terminal 140. When the connection projection 160 and the terminal 140 are welded, the second insulator 196 can be interposed between the cover plate 121 and the current collector 170.

[0126] Reference Figure 2 and Figure 4 , the operation (S200) of inserting the electrode assembly into the single cell housing is an operation of inserting the electrode assembly 110 into the single cell housing 101 through the openings 105 and 107 formed in the single cell housing 101. The electrode assembly 110 can be inserted into the single cell housing 101 through one of the first opening 105 and the second opening 107.

[0127] The operation (S300) of installing the cover plate assembly is an operation of installing the cover plate assembly 120 on the single cell housing 101 to close the openings 105 and 107. A pair of cover plate assemblies 120 can be installed to close the first opening 105 and the second opening 107. In the operation (S300) of installing the cover plate assembly, the cover plate 121 can be welded to the peripheries of the openings 105 and 107.

[0128] Figure 11 is a perspective view of a battery cell according to a second embodiment of the present invention, and Figure 12 is a cross-sectional view taken along line XI-XI in Figure 11 . Reference Figure 11 and Figure 12 , the battery cell 200 according to the second embodiment of the present invention includes a single cell housing 201, an electrode assembly 210, and a cover plate assembly 220.

[0129] The single cell housing 201 is made of a metal material (such as aluminum alloy) and can be formed in a substantially rectangular parallelepiped shape. An internal space 202 in which the electrode assembly 210 is stored can be formed inside the single cell housing 201. An opening 205 that is open in a first direction can be formed on one side of the single cell housing 201.

[0130] The electrode assembly 210 can be accommodated inside the single cell case 201. The electrode assembly 210 can enter the interior space 202 of the single cell case 201 through the opening 205. The electrode assembly 210 can be formed by winding or stacking a stack of a first electrode plate, a separator, and a second electrode plate that are in the form of a thin plate or a thin film. Since the electrode assembly 210 has the same structure as the electrode assembly 110 included in the battery cell 100 according to the first embodiment of the present invention, redundant description will be omitted.

[0131] The cover assembly 220 includes a cover plate 221, a terminal 140, a first insulator 180, a coupling protrusion 160, a current collector 170, a gasket 190, a second insulator 196, and a single cell vent 225. The cover plate 221 closes the opening 205. The outer edge of the cover plate 221 can be welded to the inner surface of the opening 205 of the single cell case 201.

[0132] The cover plate 221 can be a plate-like member having a substantially rectangular planar shape and can extend in a second direction perpendicular to the first direction. A pair of cover plate through-holes 122 passing through the cover plate 221 in the thickness direction are formed at both ends in the longitudinal direction of the cover plate 221. The cover plate 221 has a first uneven surface (not illustrated), in which a plurality of first recesses (not illustrated) are formed around the pair of cover plate through-holes 122. A plurality of fine recesses (not illustrated) can be formed on the first uneven surface. Since the first uneven surface, the first recesses, and the fine recesses of the cover plate 221 are the same as the first uneven surface 125, the first recesses 126, and the fine recesses 132 of the cover assembly 120 according to the first embodiment of the present invention, redundant description will be omitted.

[0133] A pair of terminals 140 of the cover assembly 220 are provided. The pair of terminals 140 can be arranged (one terminal is arranged at each of both ends in the longitudinal direction of the cover plate 221) to be aligned with the pair of cover plate through-holes 122 and spaced apart from each other along the first direction. One of the pair of terminals 140 can be a positive terminal, and the other can be a negative terminal.

[0134] In the cover assembly 220, a pair of first insulators 180, a pair of coupling protrusions 160, a pair of current collectors 170, a pair of gaskets 190, and a pair of second insulators 196 can each be provided in one-to-one correspondence with the pair of terminals 140.

[0135] Since the terminal 140, the first insulator 180, the coupling protrusion 160, the current collector 170, the gasket 190, and the second insulator 196 are denoted by the same reference numerals as those of the terminal 140, the first insulator 180, the coupling protrusion 160, the current collector 170, the gasket 190, and the second insulator 196 included in the cover assembly 120 according to the first embodiment of the present invention and have the same configurations as those described above, redundant descriptions of the configurations will be omitted.

[0136] One of the pair of current collectors 170 can be electrically connected to an uncoated portion of one of the first electrode plate and the second electrode plate of the electrode assembly 210, and the other current collector 170 can be electrically connected to an uncoated portion of the other of the first electrode plate and the second electrode plate of the electrode assembly 210.

[0137] The current collector 170 can be directly electrically connected to the uncoated portion by a method such as welding, or can be electrically connected to the uncoated portion through a sub-board (not illustrated).

[0138] The single cell vent 225 can be located between a pair of terminals 140 in the cover 221. When high-temperature gas or flame substances are generated inside the single cell case 201 due to overcharging, abnormal operation, etc., the single cell vent 225 can rupture and discharge emissions such as high-temperature gas or flame substances from the inside of the single cell case 201 to the outside.

[0139] Although the present disclosure has been described with reference to the embodiments shown in the drawings, these embodiments are merely illustrative, and it should be understood that those skilled in the art can derive various modifications and other equivalent embodiments based on the embodiments.

Claims

1. A battery cell, comprising: An electrode assembly; A cell housing in which the electrode assembly is stored, and an opening is formed in the cell housing to allow the electrode assembly to enter the cell housing; And A cover assembly mounted on the cell housing to close the opening, Wherein the cover assembly includes: A cover having a first uneven surface in which a plurality of first recesses are formed; A terminal having a second uneven surface in which a plurality of second recesses are formed, and the second uneven surface faces the first uneven surface; and A first insulator filling the plurality of first recesses and the plurality of second recesses and interposed between the first uneven surface and the second uneven surface.

2. The battery cell according to claim 1, wherein the inner diameter of the entrance of each of the first recesses is smaller than the maximum inner diameter of the portion of the first recess other than the entrance, and The inner diameter of the entrance of each of the second recesses is smaller than the maximum inner diameter of the portion of the second recess other than the entrance.

3. The battery cell according to claim 1, wherein the first insulator includes: A plurality of first hook protrusions formed by filling the interiors of the plurality of first recesses with molten synthetic resin and curing the synthetic resin; And A plurality of second hook protrusions formed by filling the interiors of the plurality of second recesses with molten synthetic resin and curing the synthetic resin.

4. The battery cell according to claim 1, wherein a plurality of micro recesses are formed in at least one of the first uneven surface and the second uneven surface by laser irradiation, and The first insulator includes a plurality of micro protrusions formed by filling the interiors of the plurality of micro recesses with molten synthetic resin and curing the synthetic resin.

5. The battery cell according to claim 1, wherein a first through hole is formed in the cover, A second through hole aligned with the first through hole is formed in the terminal, and The cover assembly further includes: A coupling protrusion electrically connected to the terminal through the first through hole and the second through hole; A current collector disposed on a side opposite to the terminal and the cover is between the current collector and the terminal, and the current collector is electrically connected to the coupling protrusion; And A second insulator interposed between the cover and the current collector.

6. The battery cell according to claim 5, wherein the cover assembly further includes a gasket covering an inner peripheral surface of the first through hole and elastically in close contact with the inner peripheral surface of the first through hole.

7. The battery cell according to claim 5, wherein the coupling protrusion and the terminal are connected by welding.

8. The battery cell according to claim 7, wherein the coupling protrusion includes: A column portion extending from the current collector toward the terminal with a constant diameter; And The joint portion is positioned farther from the current collector than the column portion and is tapered such that the diameter of the joint portion becomes smaller as the distance from the current collector increases, and the joint portion is welded to the terminal.

9. The battery cell according to claim 8, wherein the second through hole is tapered such that the size of the inner diameter of the second through hole becomes smaller as the distance from the cover plate increases, and the size of the inclination angle of the tapered joint portion is the same as the size of the inclination angle of the tapered second through hole.

10. The battery cell according to claim 8, wherein the coupling projection further includes an assembly portion between the column portion and the joint portion, the assembly portion being tapered such that the diameter of the assembly portion becomes smaller as the distance from the current collector increases, and the size of the inclination angle of the tapered joint portion is larger than the size of the inclination angle of the tapered assembly portion.

11. The battery cell according to claim 1, wherein a pair of terminals are provided spaced apart from each other along the longitudinal direction of the cover plate, and a pair of insulators are provided corresponding to the pair of terminals one by one.

12. The battery cell according to claim 1, wherein a pair of openings are provided in the cell housing opening in opposite directions, and a pair of cover plate assemblies are provided corresponding to the pair of openings one by one.

13. The battery cell according to claim 1, wherein a pair of terminals are provided spaced apart from each other along the longitudinal direction of the cover plate, and a pair of first insulators are provided corresponding to the pair of terminals one by one.

14. A method for manufacturing a battery cell, the method comprising: manufacturing a cover plate assembly; inserting an electrode assembly into the cell housing through an opening formed in the cell housing; and mounting the cover plate assembly on the cell housing to close the opening, wherein the manufacturing the cover plate assembly includes: preparing a cover plate having a first uneven surface in which a plurality of first recesses are formed; preparing a terminal having a second uneven surface in which a plurality of second recesses are formed; positioning the cover plate and the terminal by inserting and fixing the cover plate and the terminal into an injection molding die such that the first uneven surface and the second uneven surface are arranged to face each other inside the injection molding die; molding a first insulator by injecting molten synthetic resin into the injection molding die and curing the synthetic resin, the first insulator filling the plurality of first recesses and the plurality of second recesses and being interposed between the first uneven surface and the second uneven surface; and removing the cover plate assembly including the cover plate, the terminal, and the first insulator from the injection molding die.

15. The method for manufacturing the battery cell according to claim 14, wherein the preparing the cover plate includes: forming a plurality of first base grooves having a constant inner diameter from an inlet to a bottom in the surface of the cover plate by stamping; and A first undercut is formed by stamping the periphery of the inlet of each of the plurality of first base grooves such that the inner diameter of the inlet of each of the plurality of first base grooves is smaller than the inner diameter of the portion of each of the plurality of first base grooves other than the inlet.

16. The method for manufacturing the battery cell according to claim 15, wherein the preparing the terminal includes: forming a plurality of second base grooves having a constant inner diameter from an inlet to a bottom in the surface of the terminal by stamping; and forming a second undercut by stamping the periphery of the inlet of each of the plurality of second base grooves such that the inner diameter of the inlet of each of the plurality of second base grooves is smaller than the inner diameter of the portion of each of the plurality of second base grooves other than the inlet.

17. The method for manufacturing the battery cell according to claim 14, wherein the manufacturing the cover plate assembly further includes forming a plurality of micro recesses by emitting a laser to at least one of the first uneven surface and the second uneven surface, and in the forming the insulator, the first insulator is formed to fill the plurality of micro recesses.

18. The method for manufacturing the battery cell according to claim 14, wherein the manufacturing the cover plate assembly further includes: inserting a coupling projection through the cover plate and the terminal, and welding the coupling projection and the terminal; and before welding the coupling projection and the terminal, welding a current collector to the coupling projection.

19. The method for manufacturing the battery cell according to claim 18, wherein in the forming the insulator, a second insulator is formed together with the first insulator, the second insulator is arranged to be spaced apart from the first insulator and the cover plate is between the first insulator and the second insulator.

20. The method for manufacturing the battery cell according to claim 19, wherein the manufacturing the cover plate assembly further includes mounting a gasket on the cover plate before arranging the cover plate and the terminal, and in the forming the insulator, the first insulator is formed to be attached to one side of the gasket, and the second insulator is formed to be attached to the other side of the gasket.

Images