KR20230061094A - A Battery Cell Including A Multi-Layered Washer With Electrolyte Absorption And Insulation Properties - Google Patents

Abstract

The present invention relates to a battery cell including a washer having a multilayer structure having electrolyte hygroscopicity and insulation, and more particularly, an electrode assembly 100; A current blocking member 210 positioned above the electrode assembly 100 to block current when the internal pressure of the battery rises, a safety vent 230 connected to the top of the current blocking member 210, and an upwardly protruding shape. a cap assembly 200 including a top cap 250 having a lower outer circumferential surface contacting an upper outer circumferential surface of the safety vent 230 and having one or more venting holes 251; a cylindrical battery case 300 accommodating the electrode assembly 100 and the cap assembly 200; and a washer 400 having a multi-layer structure for absorbing moisture in the electrolyte flowing out of the venting hole 251 of the top cap 250, wherein the washer 400 includes the first film layer 410 and the first It relates to a battery cell including a washer of a multi-layer structure having electrolyte hygroscopicity and insulation, characterized in that it includes a second film layer 420 located on the first film layer 410.

Description

Battery Cell Including A Multi-Layered Washer With Electrolyte Absorption And Insulation Properties}

The present invention relates to a battery cell including a washer having a multi-layered structure having electrolyte hygroscopicity and insulating properties, and more particularly, a washer composed of two layers having a heterogeneous cross-section structure and a porous structure is located near the top cap of a cylindrical battery cell By doing so, it relates to a battery cell including a washer having a multi-layer structure having electrolyte hygroscopicity and insulation that can prevent a secondary accident by releasing venting gas to the outside and blocking the electrolyte.

As technology development and demand for mobile devices increase, secondary batteries capable of charging and discharging are used as energy sources for various mobile devices. Secondary batteries are attracting attention as an energy source for electric vehicles, hybrid electric vehicles, etc., which are proposed as alternatives to existing gasoline vehicles and diesel vehicles using fossil fuels.

Depending on the shape of the battery case, the secondary battery is classified into a cylindrical battery and a prismatic battery in which the electrode assembly is embedded in a cylindrical or prismatic metal can, and a pouch-type battery in which the electrode assembly is embedded in a pouch-type case made of an aluminum laminate sheet. .

The electrode assembly built into the battery case is a power generating device capable of charging and discharging, consisting of a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode. It is classified into a rolled jelly-roll type and a stack type in which a plurality of positive and negative electrodes of a predetermined size are sequentially stacked with a separator interposed between them. Among them, the jelly-roll type electrode assembly has advantages of being easy to manufacture and having a high energy density per weight.

On the other hand, in the secondary battery, the cylindrical battery cell may generate venting gas due to overheating, overcharging, and overcurrent, and the venting gas is released to the outside through the cylindrical battery cell venting hole to prevent explosion. However, there is a problem in that when the venting gas is released, the electrolyte inside the cylindrical battery cell leaks together, and secondary damage may occur due to the electrolyte.

In this regard, Figure 1 is a cross-sectional view showing a portion of a cylindrical battery cell according to the prior art. Referring to FIG. 1, a cylindrical battery cell according to the prior art includes an electrode assembly 10, a can 20 accommodating the electrode assembly 10, a cap assembly 30 positioned at an upper opening of the can 20, and A washer 40 mounted to surround the top cap 31 of the cap assembly 30 is included.

The washer 40 according to the prior art can absorb moisture in the electrolyte that leaks when venting gas is discharged, but has a problem in that it cannot sufficiently absorb moisture in the electrolyte because it has a simple porous structure.

Korean Patent Publication No. 2008-0058966

In the present invention for solving the above problems, when gas is generated through a venting hole in a cylindrical battery cell, the electrolyte solution discharged together with the venting gas is sufficiently absorbed and the venting gas is rapidly released to the outside. It is an object of the present invention to provide a battery cell including a washer having a multilayer structure.

A cylindrical secondary battery having a multi-layered washer according to the present invention for solving the above problems includes an electrode assembly 100; A current blocking member 210 positioned above the electrode assembly 100 to block current when the internal pressure of the battery rises, a safety vent 230 connected to the top of the current blocking member 210, and an upwardly protruding shape. a cap assembly 200 including a top cap 250 having a lower outer circumferential surface contacting an upper outer circumferential surface of the safety vent 230 and having one or more venting holes 251; a cylindrical battery case 300 accommodating the electrode assembly 100 and the cap assembly 200; and a washer 400 having a multi-layer structure for absorbing moisture in the electrolyte flowing out of the venting hole 251 of the top cap 250, wherein the washer 400 includes the first film layer 410 and the first It is characterized in that it includes a second film layer 420 located on the first film layer 410.

In addition, in the cylindrical battery cell according to the present invention, the washer 400 is characterized in that the middle is open donut shape to be located on the edge of the top surface of the battery case 300 and the edge of the top cap 250.

In addition, in the cylindrical battery cell according to the present invention, the first film layer 410 is characterized in that it is positioned so as to completely cover the venting hole 251.

In addition, in the cylindrical battery cell according to the present invention, both the first film layer 410 and the second film layer 420 are donut-shaped, but the second film layer 420 is the first film layer ( 410) is characterized in that it has an area that can completely cover.

In addition, in the cylindrical battery cell according to the present invention, the second film layer 420 is a donut shape, and the first film layer 410 is characterized in that a rectangular or trapezoidal shape.

In addition, in the cylindrical battery cell according to the present invention, the washer 400 is characterized in that it is fixed to the edge of the upper surface of the battery case 300 and the edge of the top cap 250 by an adhesive.

In addition, in the cylindrical battery cell according to the present invention, the first film layer 410 is characterized in that the heterogeneous cross-sectional structure.

In addition, in the cylindrical battery cell according to the present invention, the second film layer 420 is characterized in that the porous structure.

In addition, in the cylindrical battery cell according to the present invention, the second film layer 420 is characterized in that the mesh structure.

In addition, in the cylindrical battery cell according to the present invention, the first film layer 410 is characterized in that it is made of at least one of rayon, blended yarn, polyviscos and polynosic.

In addition, in the cylindrical battery cell according to the present invention, the second film layer 420 is polyphenylene ether, polyolefin-based polymer resin, acrylic polymer resin, polycarbonate-based polymer resin, vinyl-based polymer resin, ABS (Acrylonitrile, Butadiene , Styrene) resin, polystyrene-based polymer resin, tetrafluoroethylene, Teflon, polybutyl terephthalate, and polyethylene terephthalate.

In addition, an object of the present invention is to provide a battery module including the cylindrical battery cell described above.

In addition, an object of the present invention is to provide a battery pack including the battery module described above.

According to the battery cell including a multi-layered washer having electrolyte hygroscopicity and insulation according to the present invention, a washer having a structure in which a first film layer having excellent hygroscopicity and a second film layer having excellent air permeability are sequentially laminated is fixed to the upper surface of the case This has the advantage of preventing secondary damage such as corrosion of battery cells because the leaked electrolyte absorbs moisture and the venting gas can be quickly released.

1 is a cross-sectional view showing a portion of a cylindrical battery cell according to the prior art.
2 is a perspective view of a cylindrical battery cell according to a preferred embodiment of the present invention.
3 is an exploded perspective view of the cylindrical battery cell shown in FIG. 2;
4 is a vertical cross-sectional view of the cylindrical battery cell shown in FIG. 2 .
5 is an enlarged view of a washer cut in a vertical direction according to a preferred embodiment of the present invention.
6 is a plan view of a washer according to a modified embodiment of the present invention.

In this application, terms such as "comprise", "have" or "have" are intended to indicate that there is a feature, number, step, component, part, or combination thereof described in the specification, but one or more other It should be understood that it does not preclude the possibility of addition or existence of features, numbers, steps, operations, components, parts, or combinations thereof.

In addition, the same reference numerals are used for parts having similar functions and actions throughout the drawings. Throughout the specification, when a part is said to be connected to another part, this includes not only the case where it is directly connected, but also the case where it is indirectly connected with another element interposed therebetween. In addition, including a certain component does not exclude other components unless otherwise stated, but means that other components may be further included.

Hereinafter, a battery cell including a washer having a multi-layered structure having electrolyte hygroscopicity and insulation according to the present invention will be described with reference to the accompanying drawings.

2 is a perspective view of a cylindrical battery cell according to a preferred embodiment of the present invention, FIG. 3 is an exploded perspective view of the cylindrical battery cell shown in FIG. 2, and FIG. 4 is a vertical cross-sectional view of the cylindrical battery cell shown in FIG.

Referring to FIGS. 2 to 4, a battery cell including a washer having a multi-layered structure having electrolyte hygroscopicity and insulation according to a preferred embodiment of the present invention includes an electrode assembly 100, a cap assembly 200, and accommodating them. It includes a cylindrical battery case 300 and a washer 400.

First, the electrode assembly 100 is described. The electrode assembly 100 has a structure in which a separator 130 is interposed between the long sheet-shaped positive electrode 110 and the negative electrode 120 and then wound up. A jelly-roll type electrode assembly, Alternatively, a stacked electrode assembly composed of unit cells having a structure in which a rectangular positive electrode 110 and negative electrode 120 are stacked with a separator 130 interposed therebetween, or the unit cells are wound by a long separator film. It may be made of a stack-folding type electrode assembly, or a lamination-stack type electrode assembly in which the unit cells are stacked with a separator interposed therebetween and attached to each other.

The positive electrode tab 140 attached to the top of the electrode assembly 100 is electrically connected to the cap assembly 200, and the negative tab 150 attached to the bottom of the electrode assembly 100 is connected to the bottom of the battery case 300. .

Here, the cathode tab 150 is preferably made of a copper material having a low resistance and a high maximum allowable current.

Meanwhile, an insulating member (not shown) may be positioned above the electrode assembly 100, and the insulating member (not shown) serves to insulate between the electrode assembly 100 and the cap assembly 200.

The cap assembly 200 is located above an insulating member (not shown), electrically connected to the positive electrode tab 130 attached to the top of the electrode assembly 100, and coupled to the upper open end of the battery case 300 to form a battery case. (300) The electrode assembly 100 accommodated inside is sealed.

Specifically, in the cap assembly 200, the current blocking member 210, the current blocking gasket 220, the safety vent 230, the PTC element 240, and the top cap 250 are sequentially stacked from the bottom, and the current A crimping gasket 260 is positioned on the outer edges of the blocking member 210 and the top cap 250 .

A positive electrode tab 130 is connected to a predetermined position on the lower surface of the current blocking member 210 . Although the drawings show that the current blocking member 210 has a flat plate shape, the center portion may be convex upward.

Above the residual blocking member 210, a safety vent 230 formed so that the central part protrudes downward is located. The safety vent 230 cuts off current and exhausts gas when the pressure inside the battery rises. One side of the safety vent 230 is in contact with the PTC element 240 and the edge end surface is in contact with the crimping gasket 260.

Position of the current blocking gasket 220 so that the current blocking member 210 and the safety vent 230 can be electrically insulated from each other except for the downward protruding portion of the current blocking member 210 and the safety vent 230. do.

The PTC (Positive Temperature Coefficient) element 240 for blocking current by increasing resistance when the temperature inside the battery rises has one side of the edge in contact with the safety vent 230 and the other side in contact with the inner side of the edge of the top cap 250, there is.

In the case of a cylindrical secondary battery, gas is generated due to a number of causes such as an external impact, which increases internal pressure, and as a result, may lead to ignition or explosion.

The residual blocking member 210 and the safety vent 230 are for easily inducing the discharge of gas that acts as a cause of an increase in internal pressure of the battery, and when the inside of the battery exceeds a predetermined pressure, these residual blocking members 210 and A predetermined portion of the vent 230 is broken to prevent an explosion.

The top cap 250 located at the top seals the upper open end of the battery case 300 and forms a positive electrode terminal, and one or more venting holes 251 are formed in the top cap 250, so that the battery case ( 300) When venting gas is generated inside, it can be released to the outside to prevent an explosion.

A general cylindrical secondary battery performs a crimping process and a beading process in order to fix the cap assembly 200 .

When the crimping process and the beading process are performed, these unit parts The crimping gasket 260 is interposed to prevent deformation or breakage and improve adhesion between the current blocking member 210 and the top cap 250 .

Here, the crimping gasket 260 is not particularly limited as long as it is a material having predetermined elasticity and durability. For example, poly-butylene-terephthalate (PBT), poly-phenylene sulfide (PPS) ), perfluoroalkoxy (PFA).

Subsequently, the battery case 300 accommodates the electrode assembly 100 and the cap assembly 200, and after the negative electrode tab 150 is extended downward so that the bottom of the battery case 300 body can act as a negative electrode, the battery case (300) connected to the floor.

The battery case 300 has a beading portion 310 surrounding the outer side of the cap assembly 200, and serves to protect the cap assembly 200 from external factors such as fixing force and impact.

Next, the washer 400 will be described. As described above, when the venting gas is released, the electrolyte inside the battery cell leaks together. The washer 400 absorbs the electrolyte while releasing the gas to the outside of the battery case 300.

Specifically, the washer 400 is positioned on the edge of the upper surface of the battery case 300 and the edge of the top cap 250 so that the venting hole 251 can be completely covered. In addition, the top cap 250 has a donut shape with an open center so that the center can be exposed to the outside, and is composed of a first film layer 410 and a second film layer 420.

Here, the main function of the first film layer 410 is to absorb moisture in the electrolyte, and the second film layer 420 is to pass gas while fixing the washer 400 so as not to be separated. Of course, it is obvious that gas may pass through the first film layer 410 and a part of the electrolyte may be absorbed in the second film layer 420 .

To perform the above function, the second film layer 420 is located on the top of the first film layer 410 directly covering the upper part of the venting hole 251, and the venting hole 251 is the top cap 250. ) Since it is located along the edge, the first film layer 410 may also have the same donut shape as the second film layer 420.

Here, since the washer 400 is mainly fixed to the top edge of the case 300 and the top cap 250 by the second film layer 420, the second film layer 420 completely covers the first film layer 410. It is formed to cover an area, and at this time, the first film layer 410 is preferably positioned so as to completely cover the venting hole 251 .

5 is an enlarged view of a washer cut in a vertical direction according to a preferred embodiment of the present invention.

Referring to FIG. 5 , the washer 400 according to the present invention has the first film layer 410 and the second film layer 42 on the first film layer 410 as described above.

As shown in FIG. 5(b), the first film layer 410 preferably has an irregular cross-sectional structure such as star, prismatic, W-shaped, or cross-shaped cross-section so as to facilitate moisture absorption or adsorption of the electrolyte.

At this time, it is preferable that the void is 10 μm or more and 100 μm or less. When it is less than 10 μm, the pore is too narrow and the venting gas cannot pass smoothly, so the washer 400 is likely to fall from the cylindrical battery cell. Conversely, 100 μm If it exceeds, it is because the pores are too wide to properly absorb moisture in the electrolyte.

Here, it is preferable that the first film layer 410 is a hygroscopic and insulating material, and as an example, it may be any one or more of rayon, blended yarn, polyviscos, and polynosic.

On the other hand, the second film layer 420 may have a porous structure, for example, a mesh structure, as shown in FIG. 5 (c), and the shape of the pores may be a polygonal shape such as a triangle or a square as well as a circular and elliptical shape, The shape of the pattern and pores may be irregular, but regular ones are more preferred.

At this time, the void formed in the second film layer 420 is preferably 10 μm or more and 100 μm or less. When it is less than 10 μm, the void is too narrow and the venting gas cannot pass smoothly, so the washer 400 is a cylindrical battery cell This is because there is a high possibility of falling away from the hole, and conversely, when the thickness exceeds 100 μm, the gap is too wide, and there is a possibility that foreign substances or the like from the outside may flow into the venting hole 251.

Here, the second film layer 410 is preferably a material having insulating properties, hygroscopicity and air permeability, and examples thereof include polyphenylene ether, polyolefin-based polymer resin, acrylic polymer resin, polycarbonate-based polymer resin, vinyl-based polymer resin, and ABS. (Acrylonitrile, Butadiene, Styrene) resins, polystyrene-based polymer resins, tetrafluoroethylene, Teflon, polybutyl terephthalate, and polyethylene terephthalate.

As described above, the washer 400 of the present invention blocks the electrolyte released along with the venting gas because the second film layer 420 is located on the first film layer 410 having excellent hygroscopicity of the electrolyte. At the same time, the gas can be discharged to the outside to prevent secondary damage.

Meanwhile, the washer 400 can be firmly fixed to the edge of the upper surface of the battery case 300 and the edge of the top cap 250 using a known adhesive. At this time, the leaked electrolyte can be well absorbed by the first film layer 410 It is preferable that no adhesive is applied to the first film layer 410 or it is applied as thinly as possible. Of course, it is preferable that the application area of the adhesive is as small as possible on the second film layer 420 so that the venting gas can be easily released.

In addition, the first film layer 410 and the second film layer 420 may be integrally manufactured and then fixed to each other with an adhesive or the like, but is not limited thereto.

Here, the manufacturing method of the washer 400 may be integrally formed by applying an adhesive to the end of the first film layer 410 and attaching the second film layer 420, and the first film layer 410 as a top After placing the cap 250 on top of the venting hole 251, fix the second film layer 420 with tubing while seated on the top of the first film layer 410 and the top cap 250 so that the washer 400 is can be formed

6 is a plan view of a washer according to a modified embodiment of the present invention. Referring to FIG. 6, the washer 400 according to the modified embodiment of the present invention is the same as the washer according to the preferred embodiment of the present invention described in FIGS. 2 to 5 except for the first film layer 410. , the same content will be omitted and only the different configurations will be described.

The first film layer 410 of the washer 400 according to a modified embodiment of the present invention may have a shape corresponding to the venting hole 251, for example, a rectangular or trapezoidal shape, and they cover only the venting hole 251 A plurality of them are spaced apart from each other by a predetermined distance.

According to this modified embodiment, since the first film layer 410 is located only in the vicinity of the venting hole 251, the venting gas can be released more quickly.

The present invention may be a battery module including the aforementioned cylindrical battery cell, or a battery pack including the battery module.

As above, specific parts of the present invention have been described in detail, to those skilled in the art, these specific descriptions are only preferred embodiments, and the scope of the present invention is not limited thereby, and the scope of the present invention It is obvious to those skilled in the art that various changes and modifications are possible within the scope and scope of the technical idea, and it goes without saying that these changes and modifications fall within the scope of the appended claims.

100: electrode assembly
110: anode
120: cathode
130: separator
140: anode tab
150: cathode tab
200: cap assembly
210: current blocking member
220: current blocking gasket
230: safety vent
240: PTC element
250: top cap
251: venting hall
260: crimping gasket
300: battery case
310: beading unit
400: washer
410: first film layer
420: second film layer

Claims (13)

electrode assembly;
A current blocking member positioned above the electrode assembly that blocks current when the internal pressure of the battery rises, a safety vent connected to the upper end of the current blocking member, and a lower surface protruding upward in contact with the upper surface of the outer circumferential surface of the safety vent. a cap assembly including a top cap having the above venting holes;
a cylindrical battery case accommodating the electrode assembly and the cap assembly; and
A multi-layered washer for absorbing the electrolyte flowing out of the venting hole of the top cap;
The washer is a cylindrical battery cell, characterized in that it comprises a first film layer, and a second film layer positioned on top of the first film layer. According to claim 1,
The washer is a cylindrical battery cell, characterized in that the donut shape with an open center so that it can be located on the edge of the upper surface of the battery case and the edge of the top cap. According to claim 2,
The first film layer is a cylindrical battery cell, characterized in that positioned to completely cover the venting hole. According to claim 3,
Both the first film layer and the second film layer have a donut shape, and the second film layer has an area that can completely cover the first film layer. According to claim 3,
The second film layer is a donut shape, the first film layer is a cylindrical battery cell, characterized in that the rectangular or trapezoidal shape. According to claim 2,
The washer is a cylindrical battery cell, characterized in that fixed to the edge of the upper surface of the battery case and the edge of the top cap by adhesive. According to claim 1,
The first film layer is a cylindrical battery cell, characterized in that the heterogeneous cross-sectional structure. According to claim 7,
The second film layer is a cylindrical battery cell, characterized in that the porous structure. According to claim 8,
The second film layer is a cylindrical battery cell, characterized in that the mesh structure. According to claim 7,
The first film layer is a cylindrical battery cell, characterized in that consisting of any one or more of rayon, blended yarn, polyviscose and polynosic. According to claim 8,
The second film layer is polyphenylene ether, polyolefin-based polymer resin, acrylic polymer resin, polycarbonate-based polymer resin, vinyl-based polymer resin, ABS (Acrylonitrile, Butadiene, Styrene) resin, polystyrene-based polymer resin, tetrafluoroethylene, Cylindrical battery cell, characterized in that consisting of any one or more of Teflon, polybutyl terephthalate and polyethylene terephthalate. A battery module comprising the cylindrical battery cell according to any one of claims 1 to 11. A battery pack comprising the battery module according to claim 12.

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