KR102517383B1 - Cap assembly for rechargeable battery and rechargeable batter comprising the same - Google Patents

Abstract

The present invention relates to a cap assembly for a secondary battery and a secondary battery including the same. The cap assembly for a secondary battery according to the present invention includes a top cap forming a terminal having a discharge port formed therein, and provided under the top cap, so that the internal pressure of the battery A safety vent having a notch that ruptures when increased, a current blocking member located below the safety vent and including a central portion connected to the safety vent and an outer portion not connected, and one surface attached to the outer circumferential surface of the current blocking member A heat-resistant insulating attachment portion for insulating an outer circumferential surface of the current blocking member and the safety vent, wherein the heat-resistant insulation attachment portion includes a base layer and an adhesive layer applied to one surface of the base layer, wherein the base layer is made of glass fibers Fabric) and silicone rubber coated on the glass fiber.

Description

Cap assembly for secondary battery and secondary battery including the same

The present invention relates to a cap assembly for a secondary battery and a secondary battery including the same.

Secondary batteries, unlike primary batteries, can be recharged, and have recently been extensively researched and developed due to their small size and high capacity. As technology development and demand for mobile devices increase, demand for secondary batteries as an energy source is rapidly increasing.

In particular, lithium secondary batteries have about three times the capacity of nickel-cadmium batteries or nickel-hydrogen batteries, which are widely used as power sources for electronic equipment, and have high energy density per unit weight, so their utilization is rapidly increasing. there is.

A lithium secondary battery includes an electrode assembly in which a positive electrode, a separator, and a negative electrode are sequentially disposed, and an exterior material for sealing and housing the electrode assembly together with an electrolyte solution. Lithium secondary batteries may be classified into prismatic batteries, cylindrical batteries, and pouch-type batteries according to the type of exterior material. Among them, an exterior material for a prismatic or cylindrical secondary battery includes a case having an open end and a cap assembly sealedly coupled to the open end of the case.

Korean Patent Publication No. 10-2009-0105547

One aspect of the present invention is a cap assembly for a secondary battery capable of preventing reconnection between a safety vent and a current blocking member after the electrical connection between the safety vent and the current blocking member is separated due to the generation of internal gas in the battery, and a cap assembly for a secondary battery therefor. It is to provide a secondary battery comprising a.

A cap assembly for a secondary battery according to an embodiment of the present invention includes a top cap forming a terminal having a discharge port, a safety vent provided under the top cap and having a notch formed when the internal pressure of the battery is increased, and the safety vent. A current blocking member located below the vent, including a central portion connected to the safety vent and an outer portion not connected, and one surface attached to the outer circumferential surface of the current blocking member to insulate between the outer circumferential surface of the current blocking member and the safety vent. and a heat-resistant insulating attachment portion, wherein the heat-resistant insulation attachment portion includes a substrate layer and an adhesive layer applied to one surface of the substrate layer, wherein the substrate layer includes glass fabric and silicone rubber coated on the glass fiber. can do.

Meanwhile, a secondary battery according to an embodiment of the present invention is a secondary battery including an electrode assembly, a can having an accommodating portion in which the electrode assembly is accommodated and opened to one side, and a cap assembly covering one side of the can, wherein the cap The assembly includes a top cap forming a terminal with a discharge port, a safety vent provided under the top cap and having a notch that bursts when the internal pressure of the secondary battery increases, and a safety vent positioned under the safety vent, the safety vent A current blocking member including a central portion connected to and an outer portion not connected and an outer circumferential surface of the current blocking member attached to the safety vent, including a heat-resistant insulating attachment portion that insulates between the outer circumferential surface of the current blocking member and the safety vent, , The heat-resistant insulation attachment part includes a base layer made of glass fibers and an adhesive layer applied to both sides of the base layer, and the base layer is coated with glass fabric and the glass fibers. It may contain silicone rubber.

According to the present invention, by attaching one side of the heat-resistant insulating attachment portion made of a material having high heat resistance and high insulation characteristics to the electrically unconnected portion of the current blocking member, the electrically unconnected portion between the safety vent and the current blocking member is connection can be effectively prevented. In this case, by attaching the other surface of the heat-resistant insulating attachment part to the safety vent, the position of the current-blocking member is more firmly fixed to prevent the current-blocking member from flowing and electrically unconnected parts being connected.

In addition, by including glass fibers in the heat-resistant insulating attachment portion, it is possible to insulate the non-connected portion of the safety vent and the current blocking member without melting even at high heat. In this case, by forming the heat-resistant insulating attachment portion by coating the glass fiber with a binder, fibers of the glass fiber may not be released and may not be dissolved. In particular, since the binder is made of silicone rubber, fibers of the glass fibers are not released even at high heat, and electrically unconnected parts between the safety vent and the current blocking member can be prevented from being connected.

1 is a cross-sectional view showing a secondary battery in which a cap assembly for secondary batteries according to an embodiment of the present invention is installed.
2 is a cross-sectional view showing a cap assembly for a secondary battery according to an embodiment of the present invention.
3 is a cross-sectional view showing a current blocking member in a cap assembly for a secondary battery according to an embodiment of the present invention.
4 is an exploded perspective view showing a current blocking member and a heat-resistant insulating attachment part in a cap assembly for a secondary battery according to an embodiment of the present invention.
5 is a cross-sectional view showing an example of a base layer of a current blocking member in a cap assembly for a secondary battery according to an embodiment of the present invention.
6 is a cross-sectional view showing another example of a base layer of a current blocking member in a cap assembly for a secondary battery according to an embodiment of the present invention.
7 is a cross-sectional view illustrating a secondary battery in which a cap assembly for secondary batteries according to another embodiment of the present invention is installed.
8 is a cross-sectional view showing a cap assembly for a secondary battery according to another embodiment of the present invention.
9 is an exploded perspective view illustrating a current blocking member and a heat-resistant insulating attachment part in a cap assembly for a secondary battery according to another embodiment of the present invention.
10 is a cross-sectional view showing a current blocking member in a cap assembly for a secondary battery according to another embodiment of the present invention.

Objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments taken in conjunction with the accompanying drawings. In adding reference numerals to components of each drawing in this specification, it should be noted that the same components have the same numbers as much as possible, even if they are displayed on different drawings. In addition, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. In addition, in describing the present invention, detailed descriptions of related known technologies that may unnecessarily obscure the subject matter of the present invention will be omitted.

1 is a cross-sectional view showing a secondary battery in which a cap assembly for a secondary battery according to an embodiment of the present invention is installed, and FIG. 2 is a cross-sectional view showing a cap assembly for a secondary battery according to an embodiment of the present invention.

1 and 2, a cap assembly 100 for a secondary battery according to an embodiment of the present invention includes a top cap 110 forming a terminal having a discharge port 111, and a lower portion of the top cap 110. The safety vent 120 located on the safety vent 120, the current blocking member 130 located below the safety vent 120, and the heat-resistant insulating attachment 150 attached to the outer circumferential surface 135 of the current blocking member 130. include In addition, the cap assembly 100 for a secondary battery according to an embodiment of the present invention may further include a gasket 140 that seals and insulates between the cap assembly 100 and the can 10 .

Hereinafter, a cap assembly for a secondary battery according to an embodiment of the present invention will be described in more detail with reference to FIGS. 1 to 6 .

Referring to FIGS. 1 and 2 , a top cap 110 may be positioned on the outermost side of the two-tier battery 1 in which the electrode assembly 20 is embedded, and form a terminal having an outlet 111 therein. there is.

In addition, the top cap 110 may form a protruding terminal at the top, and may be electrically connected to the electrode assembly 20 accommodated inside the secondary battery 1 to form a positive terminal or a negative terminal.

The safety vent 120 is located inside the secondary battery 1 rather than the top cap 110, and when the internal pressure of the secondary battery 1 increases, its shape reverses toward the top cap 110 and the notch 121 is formed so that it ruptures. can be formed Here, the safety vent 120 is provided in a shape bent in the direction of the current blocking member 130 to come into contact with the current blocking member 130, and when the internal voltage of the battery increases, the top cap 110 is centered around the notch 121. ) direction, and contact with the current blocking member 130 may be released.

Also, the safety vent 120 may open and close the outlet 111 of the top cap 110 . Here, the safety vent 120 is positioned on a passage connecting the outlet 111 of the top cap 110 and the inside of the secondary battery 1 . Accordingly, before the notch 121 formed in the safety vent 120 is ruptured, the outlet 111 of the top cap 110 is closed by the safety vent 120, and the safety vent ( When the notch 121 of 120 is ruptured, the outlet 111 of the top cap 110 may be opened.

In addition, the notch 121 of the safety vent 120 may include a first notch 121a and a second notch 121b. The first notch 121a may be formed, for example, along a line of a circle or an arc, and the second notch 121b may be formed along a line of a circle or arc having a larger radius than the first notch 121a. At this time, when the internal pressure increases due to the generation of internal gas in the secondary battery 1, the central portion 123 of the safety vent 120 is moved toward the top cap 110 around the second notch 121b, and the first notch ( 121a) may be ruptured.

3 is a cross-sectional view showing a current blocking member in a cap assembly for a secondary battery according to an embodiment of the present invention, and FIG. 4 is an exploded view showing a current blocking member and a heat-resistant insulating attachment portion in a cap assembly for a secondary battery according to an embodiment of the present invention. It is a perspective view.

2 to 4, the current interrupting member 130 (CID, Current Interrupt Device) is located below the safety vent 120, and the central portion 133 connected to the safety vent 120 and the unconnected It may include an outer shell portion 134 that is a non-connected portion.

In addition, the upper end of the central part 133 of the current blocking member 130 is in contact with the lower end of the central part 123 of the safety vent 120, and when the internal pressure increases, the central part 123 of the safety vent 120 is in contact with the top cap 110. ) direction, and contact between the safety vent 120 and the current blocking member 130 is released, so that the electrical connection can be released. At this time, mutual contact between the current blocking member 130 and the safety vent 120 can be maintained by welding, and when the internal pressure increases, a portion fixed by welding is separated and the safety vent 120 and the current blocking member 130 mutually It is spaced apart and contact can be released. Meanwhile, a through hole 136 may be formed in the current blocking member 130 so that gas can move from the lower part where the electrode assembly 20 is located to the upper part where the safety vent 120 is located.

On the other hand, the current blocking member 130 is provided, for example, in the shape of a circular horizontal plate, a through hole 136 penetrating in the upper and lower directions is formed, and a central portion protruding in the direction of the safety vent 120 at the center side. (133) may be included.

5 is a cross-sectional view showing an example of a substrate layer of a current blocking member in a cap assembly for a secondary battery according to an embodiment of the present invention, and FIG. 6 is a substrate of a current blocking member in a cap assembly for a secondary battery according to an embodiment of the present invention. It is a cross-sectional view showing another example of the layer.

Referring to FIGS. 2 to 4 , the heat-resistant insulating attachment part 150 may be attached to the outer circumferential surface 135 of the current blocking member 130 . In this case, the heat-resistant insulating attachment portion 150 may insulate between the safety vent 120 and the outer circumferential surface 135 , which is a non-connected portion of the current blocking member 130 , by including an insulating material.

Accordingly, after the contact is released between the upper end of the central part 133 of the current blocking member 130 and the lower end of the central part 123 of the safety vent 120 due to the abnormal increase in internal pressure of the secondary battery 1, It is possible to prevent the upper end of the outer circumferential surface 135 of the non-connected current blocking member 130 from being connected to the lower end of the edge 122 of the safety vent 120. In particular, when insulating the non-connected portion of the current blocking member 130 and the safety vent 120 through an auxiliary gasket (not shown), the auxiliary gasket is melted due to high heat generation due to an external short circuit, and the current blocking member 130 and the non-connected portion of the safety vent 120 is electrically connected to completely prevent problems that seriously affect the stability of the secondary battery 1 .

In addition, the heat-resistant insulating attachment part 150 may include a base layer 151 and an adhesive layer 152 applied to one surface of the base layer 151 .

Referring to FIG. 5 , the base layer 151 may include glass fabric 151a and a binder 151b coated on the glass fabric 151a. Accordingly, the heat-resistant insulating attachment part 150 includes glass fiber 151a, which is a material having high heat resistance and high insulation properties, and does not melt even at high heat and reduces the ratio between the safety vent 120 and the current blocking member 130. The connection part can be insulated. In addition, by coating the glass fibers 151a with the binder 151b to prevent the fibers of the glass fibers 151a from unraveling, the fibers of the glass fibers 151a are unraveled to prevent the safety vent 120 and the current blocking member 130 from loosening. It is possible to prevent the unconnected portion from being connected. Here, the base layer 151 may be formed of, for example, glass fibers 151a and a binder 151b coated on both surfaces of the glass fibers 151a. In this case, more specifically, the base layer 151 may be formed of, for example, glass fibers 151a and a binder 151b coated on the entire surface of the glass fibers 151a.

The glass fiber 151a may be formed of a fabric sheet woven by crossing the warp and weft of glass fibers with each other. At this time, the binder 151b may penetrate into the gap between the weft and warp yarns of the glass yarn to fill the gap. The diameter of the glass yarn may be, for example, 4 to 15 μm. Here, the glass yarn is produced in the form of a long fiber by melting glass in a platinum furnace and drawing it out through a hole having a small diameter, and is excellent in heat resistance, durability, sound absorption, and electrical insulation, does not rust, and is easy to process.

The binder 151b may be made of, for example, silicon rubber. Therefore, by coating the glass fibers 151a using silicone rubber, which is a material having high heat resistance and high insulation properties, the fibers of the glass fibers 151a do not come loose even at high heat, and the safety vent 120 and the current blocking member ( 130) can be more effectively blocked from being connected.

Here, the silicone rubber is a rubber containing silicone, and has excellent heat resistance and cold resistance, and can maintain a change in strength or elongation within 10% even when left at 250 ° C for 3 days, and can maintain elasticity even at -45 ° C. Electrical properties also do not change sensitively with temperature. Various substances can be mixed with this silicone rubber. For example, silicone polymers such as organopolysiloxane used as main raw materials, silica-based fillers, extenders that increase volume and improve oil resistance, vulcanizers such as organic peroxides, processing aids such as low-content silicone oligomers, or BaO and CaO , MgO, various property improvers such as ZnO, etc. may be mixed.

When the glass fiber 151a is coated with silicone rubber, the melting point is increased compared to coating with a thermoplastic resin or phenol, and thus thermal stability may be obtained. In particular, phenol has a chain bond form in which a central element is carbon (C), but a silicone polymer, which is a main raw material of silicone rubber, has a chain bond form in which a central element is silicon (Si). Therefore, it can have high thermal stability.

Meanwhile, the silicone rubber may be coated on the glass fibers 151a at a ratio corresponding to 10 parts by weight or more, for example, based on 100 parts by weight of the glass fibers 151a. Here, the silicone rubber may be specifically coated on the glass fibers 151a at a ratio corresponding to 10 to 50 parts by weight based on 100 parts by weight of the glass fibers 151a. At this time, more specifically, for example, silicone rubber may be coated on the glass fibers 151a in a ratio corresponding to 25 to 35 parts by weight in 100 parts by weight of the glass fibers 151a. Here, referring to FIGS. 2 and 5 , when the ratio of silicone rubber in the heat-resistant insulating attachment portion 150 is greater than or equal to the lower limit value, it is possible to effectively prevent fibers of the glass fibers 151a from unraveling. That is, if the proportion of silicone rubber is small, the force for fixing the fibers of the glass fibers 151a may be insufficient so that the fibers of the glass fibers 151a do not unravel. On the other hand, when the ratio of silicone rubber in the heat-resistant insulation attachment part 150 is less than the upper limit value, the thickness of the cap assembly 100 can be made thin, and the amount of silicone rubber used can be reduced to lower the production cost.

Meanwhile, referring to FIG. 5 , the substrate layer 151 may be formed in a form in which silicone rubber is coated as a binder 151b on both sides of a glass fiber 151a, for example. At this time, the adhesive layer 152 may be formed on the outer surface of the binder 151b coated on one surface of the binder 151b coated on both surfaces of the glass fiber 151a. (Reference FIG. 2)

Also, referring to FIG. 6 , the base layer 151″ may be formed in a form in which a plurality of fabric-type sheets of glass fibers 151a″ are stacked as another example. At this time, as the binder 151b", silicone rubber may be coated on the outermost surface between the plurality of fabric-type sheets and in the stacking direction. That is, the glass fiber 151a" connects the weft and warp yarns of the glass fiber to each other. It is formed of cross-woven fabric-like sheets, the base layer 151" is a plurality of fabric-like sheets stacked, and the binder 151b", silicone rubber, is filled and coated between the plurality of fabric-like sheets and on the outermost surface. can

Here, for example, the first fabric-like sheet (a1), the second fabric-like sheet (a2), and the third fabric-like sheet (a3) are sequentially laminated to form a plurality of sheet layers, and the first fabric-like sheet ( Silicone rubber is filled between a1), the second fabric-like sheet (a2) and the third fabric-like sheet (a3), and the first fabric-like sheet (a1) and the third fabric-like sheet are outermost in the stacking direction. It may be formed by coating the outer surface of (a3) with silicone rubber. Accordingly, it is possible to more effectively insulate between the safety vent 120 and the current blocking member 130 and block heat transfer through the plurality of fabric sheets. At this time, the adhesive layer 152 may be formed on the outer surface of the coated binder 151b" coated on one side of the binder 151b" coated on both outermost surfaces of the glass fiber 151a. That is, for example, the adhesive layer 152 may be positioned on the lower surface of the binder 151b″ coated on the lower surface of the third fabric-like sheet a3 (see FIG. 2).

Referring to FIG. 2 , the adhesive layer 152 may be made of, for example, an acrylic adhesive or a silicone adhesive. Accordingly, the adhesive force is not damaged even in high heat, and the heat-resistant insulating attachment portion 150 can be firmly attached to the current blocking member 130 with strong adhesive force.

1 and 2, the gasket 140 is formed between the edge 122 of the safety vent 120 surrounding the outer circumferential surface 135 of the top cap 110 and the can 10 accommodating the electrode assembly 20. can be sealed and insulated. That is, the gasket 140 may include an insulating material to seal and insulate between the cap assembly 100 and the can 10 .

The cap assembly 100 for a secondary battery according to an embodiment of the present invention configured as described above is safe by attaching the heat-resistant insulating attachment part 150 to the outer circumferential surface 135 of the current blocking member 130, which is an electrically non-connected part. A problem in which the electrically unconnected parts of the vent 120 and the current blocking member 130 are connected can be physically prevented. More specifically, a portion of the current blocking member 130 that is electrically connected to the safety vent 120 is the central portion 133, and a portion that is not connected is the outer circumferential portion. The central part 133 of the current blocking member 130 connected to the central part 123 of the safety vent 120 through welding is driven toward the top cap 110 by generating gas inside the battery. and separates when the shape is reversed. At this time, even if the central portion 133 of the current blocking member 130 is separated from the central portion 123 of the safety vent 120, when the current blocking member 130 moves upward when the central portion 123 of the safety vent 120 moves upward. There is a problem in that the outer circumferential surface of the current blocking member 130 is electrically connected to the lower end of the safety vent 120 by moving upward together. However, in the cap assembly 100 for a secondary battery according to an embodiment of the present invention, the heat-resistant insulating attachment 150 is attached to the outer circumferential surface of the current blocking member 130, so that the current blocking member 130 is a safety vent 120. When moved in the same direction, it is possible to insulate between the outer circumferential surface of the current blocking member 130 and the safety vent 120 .

In particular, in the cap assembly for a secondary battery according to an embodiment of the present invention, the heat-resistant insulating attachment portion 150 is coated on glass fiber 151a, which is a material having high heat resistance and high insulation properties, and high heat resistance coated on the glass fiber 151a. It is made of silicone rubber, which is a material with high insulation properties and high insulation properties, and has an effect of not dissolving or loosening even when a high temperature of 950 degrees Celsius is generated. Accordingly, it is possible to insulate electrically unconnected portions of the safety vent 120 and the current blocking member 130 even when high heat is generated.

Hereinafter, a cap assembly for a secondary battery according to another embodiment of the present invention will be described.

7 is a cross-sectional view showing a secondary battery in which a cap assembly for a secondary battery according to another embodiment of the present invention is installed, and FIG. 8 is a cross-sectional view showing a cap assembly for a secondary battery according to another embodiment of the present invention.

Referring to FIGS. 7 and 8 , a cap assembly 200 for a secondary battery according to another embodiment of the present invention includes a top cap 110 forming a terminal having a discharge port 111, and a lower portion of the top cap 110. The safety vent 120 located on the side, the current blocking member 230 located below the safety vent 120, and the outer circumferential surface 235 of the current blocking member 230 and both sides attached to the safety vent 120 It includes a heat-resistant insulating attachment part 250.

The cap assembly for a secondary battery according to another embodiment of the present invention has a difference in the attachment structure of the heat-resistant insulating attachment part 250 compared to the cap assembly for a secondary battery according to the above-described embodiment.

Therefore, the present embodiment briefly describes the contents overlapping with one embodiment and focuses on the differences.

9 is an exploded perspective view showing a current blocking member 230 and a heat-resistant insulating attachment in a cap assembly for a secondary battery according to another embodiment of the present invention, and FIG. 10 is an exploded perspective view showing a current blocking member in a cap assembly for a secondary battery according to another embodiment of the present invention. It is a cross-sectional view showing the member.

In more detail, referring to FIGS. 8 to 10, in the cap assembly 200 for a secondary battery according to another embodiment of the present invention, the current blocking member 230 is located under the safety vent 120, and the current blocking member ( 230, the upper end of the central portion 233 may come into contact with the lower end of the central portion 123 of the safety vent 120. At this time, the upper end of the central portion 233 of the current blocking member 230 and the lower end of the central portion 123 of the safety vent 120 may be welded and fixed to each other through the welded portion (W). In addition, the current blocking member 230 has a through hole 236 so that gas generated inside the secondary battery 1' can move from the lower part where the electrode assembly 20 is located to the upper part where the safety vent 120 is located. ) can be formed.

In addition, the current blocking member 230 is provided in a circular horizontal plate shape, for example, and includes a body portion 231 having a through hole 236 penetrating in an up and down direction, and a central side of the body portion 231. It may include a central portion 233 formed in the safety vent 120 and protruding in the direction of the safety vent 120 and a protrusion 232 protruding in the direction of the safety vent 120 from the outer circumferential surface 235 of the body portion 231 . Here, the outer circumferential surface 235 of the current blocking member 230 may include the upper surface of the protruding portion 232 .

Also, the protruding height (b) of the protruding portion 232 in the current blocking member 230 may be formed higher than the protruding height (a) of the central portion 133 . Accordingly, when the central portion 123 of the safety vent 120 is bent toward the central portion 233 of the current blocking member 230, a bendable space may be secured.

In addition, the protrusion 232 is a portion of the edge 122 of the safety vent 120 that is located farther from the central portion 123 of the safety vent 120 to the outer side than the second notch 121b of the safety vent 120. It can be attached through the heat-resistant insulating attachment part 250. Therefore, it is located outside the first notch 121a and the second notch 121b that induce bending and rupture of the central portion 123 of the safety vent 120, and the central portion 123 of the safety vent 120 moves and Since the current blocking member 230 can be attached to a position fixing portion that does not move according to rupture, structurally strong adhesion can be maintained.

The heat-resistant insulating attachment part 250 may include a base layer 251 and adhesive layers 252 and 253 applied on both surfaces of the base layer 251 . At this time, the adhesive layer 253 is applied to one surface of the heat-resistant insulating attachment part 250 and attached to the upper surface of the outer circumferential surface 235 of the current blocking member 230 (more specifically, as shown in FIG. 8, the upper surface of the protruding part 232). attachment), an adhesive layer 252 may be applied to the other surface and attached to the lower surface of the safety vent 120 . Accordingly, the non-electrically connected portion of the current blocking member 230 may be attached to the safety vent 120 through the heat-resistant insulating attachment portion 250 . Therefore, by further attaching the other surface of the heat-resistant insulation attachment part 250 to the safety vent 120, the position of the current blocking member 230 is more firmly fixed, and the current blocking member 230 moves to electrically unconnected parts. This connection can be prevented. In this case, one surface of the heat-resistant insulating attachment part 250 may be attached to the upper surface of the protruding part 232 of the current blocking member 230, for example.

The base layer 251 may include a glass fabric and a binder coated on the glass fabric to prevent the glass fabric from unraveling. And, the binder may be made of silicone rubber.

Referring to FIG. 8 , it may be made of, for example, an acrylic adhesive or a silicone adhesive. Accordingly, the adhesive strength is not damaged even in high heat, and the heat-resistant insulating attachment portion 250 can be firmly attached between the current blocking member 230 and the safety vent 120 with strong adhesive strength. In addition, the adhesive layers 252 and 253 are formed on both sides of the base layer 251 and may be coated on the outermost surface of the binder coated on the outer surface of the glass fibers in the base layer 251 .

Hereinafter, a secondary battery according to an embodiment of the present invention will be described.

1 and 7, a secondary battery 1 according to an embodiment of the present invention includes a secondary battery cap assembly according to one embodiment described above and a secondary battery cap assembly according to another embodiment (1 ,1'). Therefore, this embodiment will briefly describe overlapping contents with the above-described embodiments, and focus on the differences.

Referring to FIGS. 1 and 2 , a secondary battery 1 according to an embodiment of the present invention includes an electrode assembly 20, a can 10 in which an accommodation portion accommodating the electrode assembly 20 is open to one side, and a can As a secondary battery 1 including a cap assembly 100 covering one side of (10), the cap assembly 100 is a top cap 110 positioned outside the secondary battery 1 in which the electrode assembly 20 is embedded. ), the safety vent 120 located below the top cap 110, the current blocking member 130 located below the safety vent 120, and the outer circumferential surface 135 of the current blocking member 130 A heat-resistant insulating attachment part 150 to which one surface is attached and a gasket 140 sealing and insulating between the cap assembly 100 and the can 10 may be included. Here, the heat-resistant insulation attachment part may include a base layer 151 and an adhesive layer 152 applied on one surface of the base layer 151 . In this case, the base layer 151 may include a glass fabric and a binder made of silicone rubber coated on the glass fabric to prevent the glass fabric from unraveling. Meanwhile, referring to FIGS. 7 and 8 , in the secondary battery 1′ according to the embodiment of the present invention, the other surface of the heat-resistant insulating attachment part 250 may be attached to the safety vent 120 . In this case, an adhesive layer 253 may be further applied to the other surface of the base layer 251 of the heat-resistant insulating attachment part 250 .

Referring to FIG. 1 , a secondary battery 1 according to an embodiment of the present invention includes an electrode assembly 20, a can 10 accommodating the electrode assembly 20, and a cap covering an open portion of the can 10. Assembly 100 may be included.

The electrode assembly 20 is a power generating element capable of charging and discharging, and a positive electrode 21, a negative electrode 22, and a separator 24 are assembled to form a stacked structure.

The separator 24 separates the anode 21 and the cathode 22 and electrically insulates them. At this time, the positive electrode 21 and the negative electrode 22 may be wound together with the separator 24 to form a jelly roll type. In addition, the separator 24 is made of an insulating material to electrically insulate between the anode 21 and the cathode 22. Here, the separator 24 may be formed of, for example, a polyolefin resin film having microporous properties such as polyethylene and polypropylene. In addition, the anode 21, the cathode 22, and the separator 24 may be formed in a sheet form, for example.

The can 10 may be formed in a shape in which a receiving portion in which the electrode assembly 20 is accommodated is opened upward. And, the can 10 may be formed in a cylindrical shape with a closed bottom, for example. At this time, the cap assembly 100 may be provided to cover the open upper side of the can 10 .

Meanwhile, the electrode assembly 20 may be electrically connected to the lower portion of the current blocking member 130 through the electrode lead 25 . Here, for example, in the electrode assembly 20, the anode 21 is electrically connected to the current blocking member 130 through the electrode lead 25, and the safety vent 120 connected to the current blocking member 130 It can be connected to the top cap 110 through. At this time, a portion protruding from the upper side of the top cap 110 may form a positive electrode terminal.

manufacturing example

1-1 base layer manufacturing

After weaving the glass fibers, the glass fibers were impregnated into the uncured silicone rubber as a binder, coated on the entire surface, and then dried to prepare a base layer.

1-2 Manufacturing of heat-resistant insulating parts

Both sides of the base layer were coated with an acrylic adhesive to a thickness of 5 μm to form an adhesive layer to prepare a heat-resistant insulating attachment part.

1-3 Secondary battery manufacturing

A secondary battery including a heat-resistant insulating attachment part was manufactured.

comparative example One

A secondary battery was manufactured in the same manner as in Preparation Example, except that the heat-resistant insulation attachment part was composed of only glass fibers and an adhesive layer without using silicone rubber.

comparative example 2

A secondary battery was manufactured in the same manner as in Preparation Example, except that urethane resin was used instead of silicone rubber for the heat-resistant insulation attachment part.

Experimental example

The temperature was raised to 950 ° C at a rate of 10 ° C / min, and the mass loss rate of the heat-resistant insulation attachment was analyzed and shown in Table 1.

manufacturing example

Comparative Example 1
Comparative Example 2
mass loss rate
5.5%

10.7%
33.7%

As shown in Table 1, in Preparation Example and Comparative Example 1, only the heat loss of the adhesive layer was observed, and in Comparative Example 2, heat loss was observed in the adhesive layer except for the glass fiber and the binder using the urethane resin. It can be seen that the mass loss rate due to heat when the temperature is raised to 950 ° C is 5.5%, while the mass loss rate is increased to 10.7% in Comparative Example 1, and the mass loss rate is further increased to 33.7% in Comparative Example 2. Therefore, it can be seen that Preparation Example shows significantly less heat-induced damage to the heat-resistant insulation attachment part at a high temperature of 950 ° C. than Comparative Example 1 and Comparative Example 2, so that the unraveling of the glass fibers can be effectively prevented even in the ultra-high temperature condition.

Although the present invention has been described in detail through specific examples, this is for explaining the present invention in detail, and the secondary battery cap assembly and the secondary battery including the same according to the present invention are not limited thereto. It will be said that various implementations are possible by those skilled in the art within the technical spirit of the present invention.

In addition, the specific protection scope of the invention will be clarified by the appended claims.

1,1': secondary battery
10: Can
20: electrode assembly
21: anode
22: cathode
23: electrode
24: separator
25: electrode lead
100: cap assembly
110: top cap
111: outlet
120: safety vent
121: notch
121a: first notch
121b: second notch
122: edge
123: central part
130,230: current blocking member
131,231: body part
133,233: central part
134: outer shell
135,235: outer circumference
136,236: through hole
140: gasket
150,250: heat-resistant insulation attachment
151,151 ",251: base layer
152,252: adhesive layer
151a, 151a", 251a: glass fiber
151b, 151b", 251b: binder
232 protrusion
a1: first fabric-like sheet
a2: second fabric type sheet
a3: Third fabric type sheet

Claims (9)

A top cap forming a terminal with an outlet formed thereon;
a safety vent provided under the top cap and formed with a notch that ruptures when the internal pressure of the battery increases;
a current blocking member located below the safety vent and including a central portion connected to the safety vent and an outer portion not connected; and
A heat-resistant insulating attachment having one surface attached to an outer circumferential surface of the current blocking member to insulate between the outer circumferential surface of the current blocking member and the safety vent;
The heat-resistant insulation attachment part includes a base layer and an adhesive layer applied to one surface of the base layer,
The base layer includes glass fabric and silicone rubber coated on the glass fabric,
The base layer of the heat-resistant insulation attachment part is formed in a form in which the silicone rubber is coated on both sides of the glass fiber,
The glass fiber is a woven sheet in which weft and warp yarns of glass fibers cross each other,
The base layer is laminated with a plurality of the fabric-like sheets,
A cap assembly for a secondary battery in which the silicone rubber is filled between a plurality of the fabric-like sheets and coated on an outermost surface in a stacking direction. delete delete delete The method of claim 1,
The silicone rubber is included in 25 to 35 parts by weight based on 100 parts by weight of the glass fiber. The method of claim 1,
The adhesive layer is a secondary battery cap assembly formed of an acrylic adhesive or a silicon adhesive. The method of claim 1,
The current blocking member
a body portion provided in the shape of a circular horizontal plate and having through-holes passing through the upper and lower directions;
a central portion formed at a central side of the body and protruding toward the safety vent; and
A protrusion protruding in the direction of the safety vent from the outer circumferential surface of the body,
A cap assembly for a secondary battery in which one surface of the heat-resistant insulating attachment part is attached to an upper surface of the protruding part. The method according to any one of claims 1 and 5 to 7,
The heat-resistant insulating attachment part further comprises an adhesive layer on the other surface,
A cap assembly for a secondary battery having one surface attached to an outer circumferential surface of the current blocking member and the other surface attached to the safety vent. A secondary battery comprising an electrode assembly, a can having an open side of an accommodation portion accommodating the electrode assembly, and a cap assembly covering one side of the can,
The cap assembly includes a top cap forming a terminal having a discharge port;
a safety vent provided under the top cap and formed with a notch that ruptures when the internal pressure of the secondary battery increases;
a current blocking member located below the safety vent and including a central portion connected to the safety vent and an outer portion not connected; and
A heat-resistant insulating attachment portion attaching an outer circumferential surface of the current blocking member to the safety vent and insulating between the outer circumferential surface of the current blocking member and the safety vent;
The heat-resistant insulation attachment part includes a base layer made of glass fibers and an adhesive layer applied to both sides of the base layer,
The base layer includes glass fibers and silicone rubber coated on the glass fibers,
The base layer of the heat-resistant insulation attachment part is formed in a form in which the silicone rubber is coated on both sides of the glass fiber,
The glass fiber is a woven sheet in which weft and warp yarns of glass fibers cross each other,
The base layer is laminated with a plurality of the fabric-like sheets,
A secondary battery wherein the silicone rubber is filled between a plurality of fabric-like sheets and coated on an outermost surface in a stacking direction.

Images