[One]This application claims the benefit of priority based on Korean Patent Application No. 2019-0053969 dated May 8, 2019, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.
[2]
The present invention relates to a cylindrical battery gasket for preventing corrosion of a battery case and a cylindrical battery including the same, and specifically, for a cylindrical battery having a structure surrounding the upper part of the cylindrical battery case from which the rust prevention layer is removed to prevent corrosion of the battery case It relates to a gasket and a cylindrical battery including the same.
background
[3]
With the increasing trend of mobile devices including cell phones, earphones and vacuum cleaners, which were mainstream wired products, are also being transformed into wireless products and manufactured. As an energy source applied to wireless products, a lithium secondary battery with high energy density and operating voltage and excellent lifespan characteristics is widely used.
[4]
According to the shape of the battery case, the lithium secondary battery includes a cylindrical secondary battery and a prismatic secondary battery in which the electrode assembly is embedded in a cylindrical or prismatic metal can, and a pouch-type secondary battery in which the electrode assembly is embedded in a pouch-type case of an aluminum laminate sheet. classified as batteries. Among them, the cylindrical secondary battery has an advantage in that it has a relatively large capacity and is structurally stable.
[5]
Cylindrical secondary batteries use a steel plate made of iron (Fe) coated with nickel to prevent corrosion as the battery case. rough
[6]
At this time, since the cut surface of the battery case is a portion where the nickel coating layer is not formed, the cross section of the iron material is exposed. Since the cut surface is still exposed even after the crimping process, rust or corrosion occurs.
[7]
Patent Document 1 relates to a secondary battery including an electrode assembly, a battery can accommodating the electrode assembly without a beading part, and a cap assembly coupled to an open end of the battery can.
[8]
Patent Document 1 uses a cap cover having a structure that covers the upper part of the rim of the cap assembly and the upper part of the battery can, and it is possible to prevent exposure of the battery case by using the cap cover, but in order to fix the cap cover A modified structure of the upper part of the battery case is used. In this way, when the upper structure of the battery case is deformed, an additional process is required, thereby complicating the manufacturing process of the battery.
[9]
Patent Document 2 relates to a cylindrical battery to which a vaporizable rust preventive agent including a polymer resin and a sodium nitrate-based material and a rust preventive gasket including a base resin are applied.
[10]
Patent Document 2 discloses a method of preventing corrosion of the crimping part even under conditions of high temperature and high humidity by generating nitric oxide by reacting a material inside the rust preventive gasket with moisture, and the nitric oxide oxidizing the surface of a cylindrical can.
[11]
Patent Document 3 discloses a cylindrical battery including a gasket having a first part including an insertion groove into which an end of a cylindrical case is inserted and fixed, and a second part extending from the first part to the inside of the case to support a cap assembly. it is about
[12]
Patent Document 3 uses a gasket having an insertion groove into which the end of the battery case can be inserted, but is applied to a cylindrical battery in which a beading part and a crimping part are not formed. It has a structure in which the end of the battery case is inserted into the unit.
[13]
As described above, as a gasket for a cylindrical secondary battery having a crimping structure, there is a high need for a gasket having a structure capable of preventing corrosion even if a portion exposed by removing the nickel coating from the upper end of the battery case is formed.
[14]
(Prior art literature)
[15]
(Patent Literature)
[16]
Korean Patent Publication No. 2012-0047114 (2012.05.11)
[17]
Korean Patent Publication No. 2018-0127938 (2018.11.30)
[18]
Korean Patent Publication No. 1998-030967 (July 25, 1998)
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[19]
The present invention is to solve the above problems, and to provide a gasket for a cylindrical battery and a cylindrical battery including the same, which has a structure surrounding the end of the battery case from which the rust-preventing coating is easily removed to prevent corrosion of the battery case do.
means of solving the problem
[20]
To achieve this object, the present invention relates to a donut-shaped cylindrical battery gasket, a support part constituting a lower portion of the gasket and supporting a cap assembly, and a clamp extending upward from the outside of the support part and constituting a side part of the gasket It may have a structure including a ping part, and an extension part extending outwardly downwardly at the distal end of the crimping part.
[21]
A protrusion structure may be formed on the upper surface of the support part.
[22]
In a state in which the crimping part is deformed for assembly of a cylindrical battery, the outermost radius of the extension may be smaller than the inner radius of the crimping part.
[23]
It may further include a lower end extending downward from the inside of the support part.
[24]
The present invention also relates to a cylindrical battery including the cylindrical battery gasket, wherein the cylindrical battery includes a cylindrical battery case accommodating an electrode assembly, a cap assembly mounted on an opening of the cylindrical battery case, and the cylindrical battery case; a cylindrical battery gasket interposed between cap assemblies, wherein an upper portion of the cylindrical battery case wraps around an outer periphery of the cap assembly and is bent toward a center, and an upper end of the cylindrical battery case is the extension of the cylindrical battery gasket may be accommodated in a receiving unit provided by
[25]
A distance between the crimping part and the end of the extension part may be the same as or smaller than the upper thickness of the battery case.
[26]
In a state in which the cylindrical battery is coupled, the accommodating part may have a structure inclined downward toward the center of the battery case.
[27]
The extension portion may be formed in a form in which a thickness decreases from a beginning portion of the extension portion toward an end direction of the extension portion.
[28]
An uncoated portion from which the rust prevention layer is removed may be formed on at least a portion of the upper portion of the battery case, and the extension portion may have a structure surrounding the uncoated portion.
[29]
The cap assembly includes a top cap and a safety vent, a concave portion is formed on a lower surface of the safety vent, and the concave portion is positioned to engage a protrusion structure formed on an upper surface of the support portion of the gasket, and the safety vent and the cylindrical battery gasket are combined
[30]
The battery case may include a beading part for supporting the cap assembly and the cylindrical battery gasket, and a lower end portion extending downwardly from the inside of the support part of the cylindrical battery gasket may be positioned between the beading part and the cap assembly.
[31]
The cap assembly may further include a current blocking member coupled to a lower surface of the safety vent, and the lower end of the gasket may include a structure extending in a central direction to support the current blocking member.
[32]
The present invention may provide a battery pack including the cylindrical battery.
Brief description of the drawing
[33]
1 is a top cross-sectional view before assembling a cylindrical secondary battery including a gasket according to the present invention.
[34]
2 is a perspective view in which a portion of a gasket according to the present invention is cut away.
[35]
3 is an upper cross-sectional view in which a cylindrical secondary battery including a gasket according to the present invention is assembled.
[36]
4 is an enlarged cross-sectional view of a gasket extension according to the present invention.
Modes for carrying out the invention
[37]
Hereinafter, embodiments in which those of ordinary skill in the art to which the present invention pertains can easily practice the present invention will be described in detail with reference to the accompanying drawings. However, in the detailed description of the principle of operation of the preferred embodiment of the present invention, if it is determined that a detailed description of a related well-known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.
[38]
In addition, the same reference numerals are used throughout the drawings for parts having similar functions and functions. Throughout the specification, when it is said that a part is connected to another part, it includes not only a case in which it is directly connected, but also a case in which it is indirectly connected with another element interposed therebetween. In addition, the inclusion of a certain component does not exclude other components unless otherwise stated, but means that other components may be further included.
[39]
In the present invention, the structure of a gasket, which is a sealing member of a cylindrical battery, is modified in order to prevent corrosion of the battery case of the cylindrical battery.
[40]
In general, cylindrical batteries use a steel plate having a nickel coating layer formed on the surface to prevent corrosion, and the steel plate is deep-drawn to form a battery case, and the molded part is cut from the steel plate to be used as a battery case.
[41]
At this time, since the cut surface is a portion where the nickel coating layer is not formed, it may rust or corrode when exposed to air.
[42]
Accordingly, the present invention solves the above problems by applying a new shape to a gasket used as a sealing member of a cylindrical battery. That is, the structure was changed so that the gasket surrounds the upper end portion of the battery case where the nickel coating layer is not formed.
[43]
In this regard, FIG. 1 is an upper cross-sectional view before assembling a cylindrical secondary battery including a gasket according to the present invention, and FIG. 2 is a perspective view showing a part of the gasket according to the present invention cut away.
[44]
1 and 2 , the cap assembly 110 includes a top cap 101 having a protruding structure serving as a positive electrode terminal, a safety vent 102 positioned at a lower portion surrounding the outer periphery of the top cap 101 . , a current blocking member 104 in contact with the lower surface of the safety vent 102 and a CID gasket 103 for blocking contact between the current blocking member 104 and the outer periphery of the safety vent 102 .
[45]
The gasket used to secure insulation between the cap assembly 110 and the battery case and to seal the battery case includes a support 121 supporting the cap assembly and a crimping part 122 extending upward from the outside of the support part 121 . Including, an extension portion 123 extending downwardly to the outside is formed at the distal end of the crimping portion 122 .
[46]
The gasket includes a lower end 124 extending downward from the inside of the support 121, and the lower end 124 is for securing insulation between the current blocking member 104 and the current blocking member 104 and the safety vent 102. It includes a structure further extending in the central direction to support the CID gasket (103).
[47]
The safety vent 102 has a concave portion 105 formed on its lower surface and a protrusion structure 125 formed on the upper surface of the support portion 121 of the gasket. The cap assembly including the vent may be stably coupled to the gasket, and the cap assembly may be fixed in place by such coupling.
[48]
Although the protrusion structure 125 is illustrated as a ring-shaped structure of two rows, it may be a structure in which one or more rows of spaced protrusions are continuously or discontinuously formed.
[49]
The extension part 123 forms a receiving part 126 that can accommodate the end of the battery case, and the thickness of the extension part 123 decreases from the start part 123a of the extension part toward the end part 123b of the extension part. Since the battery case is accommodated in the receiving part 126, the end of the extension part 123b may be more closely attached to the battery case.
[50]
3 is an upper cross-sectional view of a cylindrical secondary battery including a gasket according to the present invention is assembled, and FIG. 4 is an enlarged cross-sectional view of a gasket extension according to the present invention. Referring to FIGS. 3 and 4, the cylindrical battery of FIG. 1 and 2 shows a state in which the gasket and cap assembly 110 is accommodated in the battery case 200 and sealed.
[51]
The upper part 201 of the battery case 200 is bent toward the center of the battery case through a crimping process and is deformed to a structure surrounding the upper surface of the gasket and the outer periphery of the cap assembly, and the upper part of the deformed battery case 200 The (201) end (202) is received in the receiving portion (126) of the gasket provided by the extension (123).
[52]
The length of the extension portion 123 is not particularly limited, but is a length capable of enclosing the uncoated portion 201a from which the rust prevention layer formed on the upper portion of the battery case is removed. The uncoated portion 201a from which the rust preventive layer is removed is not formed at the end, but is pushed out from the upper part of the battery case to the outer or inner lower part by the deformation of the metal during the manufacture of the battery case. Conventionally, this point was not recognized at all, and the uncoated part was formed at the distal end and was designed with the expectation that corrosion would be prevented by the contact of the distal end with the gasket. I could not prevent continuous corrosion from occurring in the uncoated part.
[53]
In particular, in the case of batteries exposed to the outside, rust prevention is very important due to condensation of water vapor due to temperature changes, contamination from rain or snow, etc. Although still not solved, the present invention was able to solve this problem by recognizing that the uncoated part is pushed out.
[54]
However, considering that the extension part 123 is located on the upper outer surface of the battery case, in order to prevent an increase in the overall length of the cylindrical battery, it can be made of a length that does not extend to the maximum protrusion upward of the battery case crimping part. there is.
[55]
Specifically, referring to FIG. 4 , the size of the outermost radius a1 of the extension portion may be smaller than the inner radius a2 of the crimping portion.
[56]
In addition, by applying a structure in which the thickness decreases in the direction of the distal end of the extension, the overall length of the cylindrical battery is prevented from increasing due to the addition of the extension.
[57]
After the cap assembly 110 and the gasket are accommodated in the battery case 200, when the gasket and the cap assembly 110 are in close contact with the crimping part 122 and the beading part 203 formed, the gasket protrusion structure 125 ) is inserted into the concave portion 105 of the safety vent to form a structure that can be stably fixed.
[58]
The battery case 200 has a structure in which the beading part 203 is formed, and the lower end 124 of the gasket is positioned between the beading part 203 and the cap assembly 110 and blocks their contact.
[59]
It is preferable that the extension part 123 be positioned on the outer surface of the battery case 200 so that it is in close contact with the battery case 200, and the separation distance b1 between the ends of the crimping part 122 and the extension part 123 in the gasket is the above. It may be the same as the upper thickness (b2) of the battery case.
[60]
Alternatively, since the gasket may be made of an elastic material, the distance b1 between the ends of the crimping part 122 and the extension part 123 may be smaller than the upper thickness b2 of the battery case, and the battery case 200 ), when the upper part of the accommodating part 126 is inserted into the accommodating part 126, the accommodating part 126 is deformed so that the upper part of the battery case can be seated.
[61]
On the other hand, the receiving part 126 may have a structure inclined downward in the direction of the center of the battery case, so even if a force to return to the state before being crimped by the rollback phenomenon acts on the top of the crimped battery case, the It is possible to minimize exposure of the coating portion, and there is an additional effect that the sealing of the battery case can be stably maintained.
[62]
The present invention can also provide a battery pack in which cylindrical batteries having the above structure are connected in series and/or in parallel to provide a battery pack with improved safety while having high output and high capacity.
[63]
Those of ordinary skill in the art to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above contents.
[64]
(Explanation of symbols)
[65]
101: top cap
[66]
102: safety vent
[67]
103: CID gasket
[68]
104: current blocking member
[69]
105: recess
[70]
110: cap assembly
[71]
121: support
[72]
122: crimping unit
[73]
123: extension
[74]
123a: the beginning of the extension
[75]
123b: end of extension
[76]
124: lower part
[77]
125: projection structure
[78]
126: storage unit
[79]
200: battery case
[80]
201: upper battery case
[81]
201a: uncoated part
[82]
202: upper end of the battery case
[83]
203: beading unit
[84]
a1: the outermost radius of the extension
[85]
a2: inner radius of the crimping part
[86]
b1: distance between the crimping part and the end of the extension part
[87]
b2: upper thickness of the battery case
Industrial Applicability
[88]
As described above, the present invention has a structure in which a receiving part capable of accommodating the upper end of the battery case is formed in the crimping part of the gasket, and nickel (Ni) that is inevitably generated at the upper end of the battery case during the manufacturing process of the battery case ) As a plated fracture part, corrosion of the iron (Fe) exposed part can be prevented.
[89]
In addition, by forming the extended portion of the gasket in a downwardly inclined structure in the direction of the center of the battery case, it is possible to prevent the upper end of the battery case from being separated from the housing of the gasket due to rollback of the crimping portion.
[90]
In addition, by limiting the length of the extension portion of the gasket to a certain range, it is possible to prevent the overall size of the cylindrical secondary battery from increasing even after the extension portion is formed.

WE CLAIMS

A donut-shaped cylindrical battery gasket comprising: a support part constituting a lower portion of the gasket and supporting a cap assembly; and a crimping part constituting a side part of the gasket and extending upwardly from the outside of the support part. Including, at the end of the crimping portion is formed a cylindrical battery gasket extending outwardly downward.
[Claim 2]
The gasket for a cylindrical battery according to claim 1, wherein a protrusion structure is formed on an upper surface of the support part.
[Claim 3]
The gasket for a cylindrical battery according to claim 1, wherein the outermost radius of the extension part in a deformed state of the crimping part for assembly of the cylindrical battery is smaller than the inner radius of the crimping part.
[Claim 4]
According to claim 1, Cylindrical battery gasket further comprising a lower end extending downwardly from the inside of the support portion.
[Claim 5]
Cylindrical battery case housing the electrode assembly; a cap assembly mounted on the open part of the cylindrical battery case; and a cylindrical battery gasket according to any one of claims 1 to 4 interposed between the cylindrical battery case and the cap assembly; Including, an upper portion of the cylindrical battery case wraps around the outer periphery of the cap assembly and is bent toward a central portion, and the upper end of the cylindrical battery case is a cylindrical battery accommodated in a receiving portion provided by the extension portion of the cylindrical battery gasket. battery.
[Claim 6]
The cylindrical battery according to claim 5, wherein the distance between the crimping part and the end of the extension part is the same as or smaller than the upper thickness of the battery case.
[Claim 7]
The cylindrical battery according to claim 5, wherein, in a state in which the cylindrical battery is coupled, the accommodating part has a structure inclined downward toward the center of the battery case.
[Claim 8]
The cylindrical battery according to claim 5, wherein the extension portion has a shape that decreases in thickness from the beginning of the extension to the end of the extension.
[Claim 9]
The cylindrical battery according to claim 5, wherein an uncoated portion from which the rust prevention layer is removed is formed on at least a portion of the upper portion of the battery case, and the extension portion surrounds the uncoated portion.
[Claim 10]
The method of claim 5, wherein the cap assembly includes a top cap and a safety vent, and a concave portion is formed on a lower surface of the safety vent, and the concave portion is positioned to engage with a protrusion structure formed on an upper surface of a support portion of the cylindrical battery gasket. A cylindrical battery in which a safety vent and the cylindrical battery gasket are coupled.
[Claim 11]
The cylindrical battery case according to claim 5, wherein the battery case includes a beading part for supporting the cap assembly and the cylindrical battery gasket, and a lower end extending downward from the inside of the cylindrical battery gasket support part is located between the beading part and the cap assembly. battery.
[Claim 12]
The cylindrical battery according to claim 11, wherein the cap assembly further comprises a current blocking member coupled to a lower surface of the safety vent, and the lower end of the gasket has a structure extending in a central direction to support the current blocking member.
[Claim 13]
A battery pack comprising the cylindrical battery according to claim 5.