This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0022033 dated February 25, 2019, and all contents disclosed in the documents of the Korean patent application are incorporated as a part of this specification.
[3]
technical field
[4]
The present invention relates to a venting device, and more particularly, to a venting device that is inserted into a sealing part of a pouch of a secondary battery to discharge gas inside the pouch to the outside, and minimizes bending of a leaf spring in a closed state. it's about
background
[5]
In general, types of secondary batteries include a nickel cadmium battery, a nickel hydrogen battery, a lithium ion battery, and a lithium ion polymer battery. These secondary batteries are not only used in small products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, Portable Game Devices, Power Tools and E-bikes, but also in large products requiring high output such as electric and hybrid vehicles and surplus power generation. It is also applied and used in power storage devices that store power or renewable energy and power storage devices for backup.
[6]
The secondary battery is classified into a pouch type, a can type, and the like, according to a material of a case for accommodating the electrode assembly. The pouch type accommodates the electrode assembly in a pouch made of a flexible polymer material. In addition, the can type accommodates the electrode assembly in a case made of a material such as metal or plastic.
[7]
On the other hand, secondary batteries are threatened with safety due to various problems such as internal short circuit due to external impact, heat generation due to overcharging and overdischarging, and electrolyte decomposition and thermal runaway. In particular, when gas is generated due to electrolyte decomposition and the pressure inside the secondary battery increases, the secondary battery explodes.
[8]
Specifically, when the secondary battery is repeatedly charged and discharged, gas is generated through an electrochemical reaction between the electrolyte and the electrode active material. At this time, the generated gas increases the internal pressure of the secondary battery, thereby causing problems such as weakening of bonding force between parts, damage to the case of the secondary battery, early operation of the protection circuit, deformation of the electrode, internal short circuit, and explosion. Accordingly, in the case of the Can Type secondary battery, a protective member such as a CID filter and a safety vent is provided to physically block the electrical connection when the pressure inside the case increases. However, in the case of a conventional pouch type secondary battery, such a protection member is not sufficiently provided.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[9]
SUMMARY OF THE INVENTION An object of the present invention is to provide a venting device that is inserted into a sealing part of a pouch of a secondary battery, discharges gas inside the pouch to the outside, and minimizes bending of a leaf spring in a closed state.
[10]
The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.
means of solving the problem
[11]
According to an embodiment of the present invention, there is provided a venting device inserted into a sealing portion of a pouch of a venting device secondary battery, comprising: a housing inserted between both surfaces of the sealing portion and sealed together with the sealing portion; a sheet formed inside the housing and through which a passage communicating the inside and the outside of the pouch is formed; a leaf spring which opens and closes the passage according to the internal pressure of the pouch, and is made of metal having elastic force; and a ball disposed between the seat and the leaf spring, at the outlet side of the passage, contacting or spaced apart from the seat to open and close the passage, wherein the ball is formed in a hemispherical shape and the leaf spring is attached to the inner surface of
[12]
In addition, the leaf spring, a central portion formed in the center; and a peripheral portion extending outwardly from the central portion, wherein the ball is attached to the central portion, and a gas exhaust hole may be perforated in the peripheral portion.
[13]
In addition, the leaf spring may have a cap shape with one side convex outward, and an insertion space into which the seat and the ball are inserted may be formed.
[14]
In addition, the leaf spring, the other end may be bent toward the seat inserted into the insertion space.
[15]
In addition, the leaf spring has a flat plate shape, and may contact the seat.
[16]
In addition, in the sheet, the inner peripheral edge of the exit side surface of the passage may be chamfered or filleted.
[17]
In addition, the sheet, the outer peripheral edge of the exit side surface of the passage may be chamfered or filleted.
[18]
In addition, the housing may include an upper housing and a lower housing having different shapes or sizes from each other.
[19]
Also, the width of the lower housing may be smaller than the width of the upper housing.
[20]
In addition, the upper housing may have a circular cylinder shape, and the lower housing may have an elliptical cylinder shape.
[21]
The present invention also provides a pouch-type secondary battery in which the venting device is inserted into the sealing portion of the pouch, a battery module including the pouch-type secondary battery as a unit battery, and a device including the battery module.
[22]
The device includes a computer, a notebook computer, a smart phone, a mobile phone, a tablet PC, a wearable electronic device, a power tool, an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid an electric vehicle (Plug-in Hybrid Electric Vehicle, PHEV) or an electric power storage device, but is not limited thereto.
[23]
Since the structure of the battery module and device and their manufacturing method are known in the art, a detailed description thereof will be omitted herein.
[24]
Other specific details of the invention are included in the detailed description and drawings.
Effects of the Invention
[25]
According to the embodiments of the present invention, there are at least the following effects.
[26]
By minimizing the bending of the leaf spring in the closed state of the venting device, it is possible to reduce the deviation of the opening pressure between the venting devices.
[27]
In addition, it is possible to reduce the deviation between the designed opening pressure value and the actual opening pressure before manufacturing the venting device.
[28]
The effect according to the present invention is not limited by the contents exemplified above, and more various effects are included in the present specification.
Brief description of the drawing
[29]
1 is an assembly view of a secondary battery including a venting device according to an embodiment of the present invention.
[30]
FIG. 2 is a perspective view of the secondary battery of FIG. 1 that has been manufactured;
[31]
3 is a cross-sectional view of a pouch film forming a battery case according to an embodiment of the present invention.
[32]
4 is a perspective view of a venting device according to an embodiment of the present invention.
[33]
5 is a schematic diagram of a venting device in which a ball has a spherical shape.
[34]
6 is a schematic diagram of a sheet according to an embodiment of the present invention;
[35]
7 is a schematic view showing a state in which a ball is seated on a seat according to an embodiment of the present invention.
[36]
8 is a schematic diagram of a leaf spring according to an embodiment of the present invention.
[37]
9 is a schematic diagram illustrating a state in which a leaf spring according to an embodiment of the present invention surrounds a seat and a ball.
[38]
10 is a schematic view showing a state in which the other end of the leaf spring according to an embodiment of the present invention is bent toward the seat side.
[39]
11 is a schematic diagram illustrating a venting device in which a leaf spring and a seat are inserted into the housing according to an embodiment of the present invention and the manufacturing is completed.
[40]
12 is an operation diagram illustrating an operation of the venting device according to an embodiment of the present invention.
[41]
13 is a schematic view showing a state in which the manufacturing of the venting device according to another embodiment of the present invention is completed.
[42]
14 is an operation diagram illustrating an operation of a venting device according to another embodiment of the present invention.
Modes for carrying out the invention
[43]
Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.
[44]
Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless clearly specifically defined.
[45]
The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural, unless specifically stated otherwise in the phrase. As used herein, “comprises” and/or “comprising” does not exclude the presence or addition of one or more other components in addition to the stated components.
[46]
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[47]
FIG. 1 is an assembly view of a secondary battery 1 including a venting device 15 according to an embodiment of the present invention, and FIG. 2 is a perspective view of the secondary battery 1 of FIG. 1 that has been manufactured.
[48]
In the process of manufacturing the pouch-type secondary battery 1, first, a slurry in which an electrode active material, a binder, and a plasticizer are mixed is applied to a positive electrode current collector and a negative electrode current collector to prepare electrodes such as a positive electrode and a negative electrode, and this is used as a separator. After forming the electrode assembly 10 of a predetermined shape by laminating on both sides of the electrode assembly 10 is inserted into the battery case 13, the electrolyte is injected and then sealed.
[49]
Specifically, the electrode assembly 10 includes two types of electrodes, such as an anode and a cathode, and a separator interposed between the electrodes to insulate the electrodes from each other. The electrode assembly 10 may be of a stack type, a jelly roll type, a stack-and-fold type, or the like. Two types of electrodes, that is, a positive electrode and a negative electrode, have a structure in which an active material slurry is applied to an electrode current collector in the form of a metal foil or metal mesh including aluminum and copper, respectively. In general, the slurry may be formed by stirring a granular active material, an auxiliary conductor, a binder, a plasticizer, and the like in a state in which a solvent is added. The solvent is removed in a subsequent process.
[50]
As shown in FIG. 1 , the electrode assembly 10 includes an electrode tab 11 . The electrode tab 11 protrudes from the positive electrode and the negative electrode of the electrode assembly 10 , respectively, and serves as a path through which electrons can move between the inside and the outside of the electrode assembly 10 . The current collector of the electrode assembly 10 includes a portion to which the electrode active material is applied and a distal portion to which the electrode active material is not applied, that is, an uncoated portion. In addition, the electrode tab 11 may be formed by cutting the uncoated area or may be formed by connecting a separate conductive member to the uncoated area by ultrasonic welding or the like. As shown in FIG. 1 , the electrode tabs 11 may protrude side by side from one side of the electrode assembly 10 in the same direction, but are not limited thereto and may protrude in different directions.
[51]
An electrode lead 12 is connected to the electrode tab 11 of the electrode assembly 10 by spot welding or the like. A part of the electrode lead 12 is surrounded by the insulating portion 14 . The insulating part 14 is positioned limitedly in the sealing part 134 to which the upper case 131 and the lower case 132 of the battery case 13 are thermally fused, and is attached to the battery case 13 . In addition, electricity generated from the electrode assembly 10 is prevented from flowing to the battery case 13 through the electrode lead 12 , and the sealing of the battery case 13 is maintained. Accordingly, the insulating portion 14 is made of a non-conductive material that does not conduct electricity well. In general, as the insulating part 14, an insulating tape that is easy to attach to the electrode lead 12 and has a relatively thin thickness is often used. have.
[52]
The electrode lead 12 has one end connected to the positive electrode tab 111 , one end connected to the positive electrode lead 121 and the negative electrode tab 112 extending in the protruding direction of the positive electrode tab 111 , and the negative electrode tab 112 . ) includes a negative lead 122 extending in the protruding direction. On the other hand, as shown in FIG. 1 , the positive lead 121 and the negative lead 122 both have the other end protruding to the outside of the battery case 13 . Accordingly, electricity generated inside the electrode assembly 10 may be supplied to the outside. In addition, since the positive electrode tab 111 and the negative electrode tab 112 are formed to protrude in various directions, respectively, the positive electrode lead 121 and the negative electrode lead 122 may also extend in various directions.
[53]
The material of the positive lead 121 and the negative lead 122 may be different from each other. That is, the positive electrode lead 121 may be made of the same aluminum (Al) material as the positive electrode current collector, and the negative electrode lead 122 may be made of the same copper (Cu) material as the negative electrode current collector or nickel (Ni) coated copper. And a portion of the electrode lead 12 protruding to the outside of the battery case 13 becomes a terminal portion, and is electrically connected to the external terminal.
[54]
The battery case 13 is a pouch made of a soft material. Hereinafter, the battery case 13 will be described as a pouch. The battery case 13 accommodates and seals the electrode assembly 10 so that a portion of the electrode lead 12, that is, the terminal portion is exposed. As shown in FIG. 1 , the battery case 13 includes an upper case 131 and a lower case 132 . A cup portion 133 is formed in the lower case 132 to provide an accommodating space 1331 accommodating the electrode assembly 10 , and the upper case 131 has the electrode assembly 10 in the battery case 13 . The accommodation space 1331 is covered from the top so as not to be separated to the outside of the . At this time, as shown in FIG. 1 , the cup part 133 provided with the accommodation space 1331 is also formed in the upper case 131 , so that the electrode assembly 10 may be accommodated therein. The upper case 131 and the lower case 132 may be manufactured with one side connected to each other as shown in FIG.
[55]
After the upper case 131 and the lower case 132 of the battery case 13 contact each other, the sealing part 134 formed on the edge is sealed. At this time, as shown in FIG. 1 , according to an embodiment of the present invention, the venting device 15 is inserted between both surfaces of the sealing part 134 and sealed together, thereby being fixed in the sealing part 134 . do. And, the venting device 15 includes a passage communicating the inside and the outside of the battery case 13, and when the internal pressure of the battery case 13 increases, the gas inside is discharged to the outside to control the pressure. Details of the venting device 15 will be described later.
[56]
When the electrode lead 12 is connected to the electrode tab 11 of the electrode assembly 10 and the insulating part 14 is formed on a portion of the electrode lead 12 , the cup part 133 of the lower case 132 is provided. The electrode assembly 10 is accommodated in the accommodation space 1331 , and the upper case 131 covers the space from the top. Then, the electrolyte is injected therein and the sealing portion formed on the edges of the upper case 131 and the lower case 132 is sealed. The electrolyte is to move lithium ions generated by the electrochemical reaction of the electrode during charging and discharging of the secondary battery 1, and a polymer using a non-aqueous organic electrolyte or a polymer electrolyte, which is a mixture of lithium salt and high-purity organic solvents. may include. Through this method, as shown in FIG. 2 , the pouch-type secondary battery 1 may be manufactured.
[57]
3 is a cross-sectional view of the pouch film 135 forming the battery case 13 according to an embodiment of the present invention.
[58]
The battery case 13 is manufactured by drawing and molding the pouch film 135 . That is, it is manufactured by stretching the pouch film 135 to form the cup portion 133 . The pouch film 135 includes a gas barrier layer 1351 , a surface protection layer 1352 , and a sealant layer 1353 as shown in FIG. 3 .
[59]
The gas barrier layer 1351 secures the mechanical strength of the battery case 13 , blocks the ingress of gas or moisture from the outside of the secondary battery 1 , and prevents leakage of electrolyte. In general, the gas barrier layer 1351 includes a metal and mainly uses an aluminum thin film (Al Foil). Aluminum can secure a predetermined level or more of mechanical strength, while having a light weight, and supplementing the electrochemical properties of the electrode assembly 10 and the electrolyte and securing heat dissipation. However, the present invention is not limited thereto, and various materials may be included in the gas barrier layer 1351 . For example, it may be one or a mixture of two or more selected from the group consisting of iron (Fe), carbon (C), chromium (Cr), manganese (Mn), nickel (Ni), and aluminum (Al). In this case, when the gas barrier layer 1351 is made of an iron-containing material, mechanical strength is improved, and when the gas barrier layer 1351 is made of an aluminum-containing material, flexibility is improved, so that each characteristic may be taken into consideration.
[60]
The surface protective layer 1352 is made of a polymer, and is located in the outermost layer to protect the secondary battery 1 from friction and collision with the outside, and electrically insulates the electrode assembly 10 from the outside. Here, the outermost layer refers to a direction opposite to a direction in which the electrode assembly 10 is positioned with respect to the gas barrier layer 1351 and an outward direction. The surface protective layer 1352 is polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polypara It may be made of at least one material selected from the group consisting of phenylenebenzobisoxazole, polyarylate, Teflon, and glass fiber. In particular, a polymer such as nylon resin or polyethylene terephthalate (PET) having mainly abrasion resistance and heat resistance is used. In addition, the surface protection layer 1352 may have a single-layer structure made of any one material or a composite film structure in which two or more materials are each layered.
[61]
The sealant layer 1353 is made of a polymer and is located in the innermost layer to directly contact the electrode assembly 10 . The pouch-type battery case 13 is a cup part ( 133) while forming. Then, when the electrode assembly 10 is accommodated in the receiving space 1333, the electrolyte is injected. After that, when the upper case 131 and the lower case 132 are brought into contact with each other and thermocompressed to the sealing part 134 , the sealant layers 1353 are adhered to each other, thereby sealing the battery case 13 . In this case, the sealant layer 1353 must have insulation because it directly contacts the electrode assembly 10 , and must have corrosion resistance because it also comes in contact with the electrolyte. In addition, since it is necessary to completely seal the inside to block material movement between the inside and the outside, it must have high sealing properties. That is, the sealing portion 134 to which the sealant layers 1353 are bonded should have excellent thermal bonding strength. In general, the sealant layer 1353 includes polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly It may be made of at least one material selected from the group consisting of paraphenylenebenzobisoxazole, polyarylate, Teflon, and glass fiber. In particular, a polyolefin-based resin such as polypropylene (PP) or polyethylene (PE) is mainly used. Polypropylene (PP) has tensile strength, rigidity, surface hardness, abrasion resistance, It has excellent mechanical properties such as heat resistance and chemical properties such as corrosion resistance, and is mainly used for manufacturing the sealant layer 1353 . Furthermore, it may be composed of Cated Polypropylene or polypropylene-butylene-ethylene terpolymer. In addition, the sealant layer 1353 may have a single-layer structure made of any one material or a composite film structure in which two or more materials are each layered.
[62]
4 is a perspective view of the venting device 15 according to an embodiment of the present invention.
[63]
The secondary battery 1 according to an embodiment of the present invention further includes at least one venting device 15 . According to an embodiment of the present invention, by minimizing the bending of the leaf spring 153 in the closed state of the venting device 15 , it is possible to reduce the deviation of the opening pressure between the venting devices 15 . In addition, the deviation between the designed opening pressure value and the actual opening pressure before the manufacture of the venting device 15 can be reduced. Here, the opening pressure refers to a specific pressure inside the battery case 13 when the venting device 15 is opened.
[64]
To this end, in the venting device 15 that is inserted into the sealing part 134 of the pouch of the secondary battery 1 , the venting device 15 according to an embodiment of the present invention includes both surfaces of the sealing part 134 . a housing 151 inserted therebetween and sealed together with the sealing part 134; a sheet 152 formed inside the housing 151 and through which a passage 154 communicating the inside and the outside of the pouch is formed; a leaf spring 153 that opens and closes the passage 154 according to the internal pressure of the pouch, and is made of metal having elastic force; and a ball 155 disposed between the seat 152 and the leaf spring 153 and contacting or spaced apart from the seat 152 at the outlet side of the passage 154 to open and close the passage 154 . ), but the ball 155 is formed in the shape of a hemisphere and is attached to the inner surface of the leaf spring 153 .
[65]
The housing 151 is inserted between both surfaces of the sealing part 134 to be sealed together with the sealing part 134 . When the housing 151 is inserted into both surfaces of the sealing part 134 , the sealant layer 1353 , which is the innermost layer of the sealing part 134 , contacts the housing 151 . And, when heat and pressure are applied, the sealant layer 1353 of the sealing part 134 may be fused together with the housing 151 to be sealed. 6 , the housing 151 includes an upper housing 1511 and a lower housing 1512 , and a step may be formed between the upper housing 1511 and the lower housing 1512 . Such a step may be formed by the shape or size of the upper housing 1511 and the lower housing 1512 being different from each other. For example, the upper housing 1511 may have a circular cylinder shape with a cross-section, and the lower housing 1512 may have an elliptical cylinder shape with an elliptical cross-section. Alternatively, the width of the lower housing 1512 may be smaller than the width of the upper housing 1511 . Accordingly, since the lower housing 1512 is inserted between both surfaces of the sealing unit 134 and sealed together, the lower housing 1512 is fused to the inner surface of the sealing unit 134 , and the upper housing 1511 may protrude to the outside of the pouch.
[66]
At this time, if the width of the lower housing 1512 is excessively large, since the sealing part 134 must also be greatly deformed, the sealing of the sealing part 134 is highly likely to be destroyed. Therefore, the width of the lower housing 1512 may be smaller than the thickness of the sealing part 134 , and in particular, it is preferable that the major axis of the cross section is 6 mm or less. And, as described above, the lower housing 1512 has an elliptical cylindrical shape with an elliptical cross-section, so that the lower housing 1512 is easily sealed to the sealing part 134, and the sealing can be maintained without being destroyed for a long time. have.
[67]
In addition, if the upper housing 1511 is excessively large, the upper housing 1511 protruding to the outside of the pouch may interfere with other surrounding secondary batteries 1 . As such, it may not be easy to assemble the package or module of the secondary battery 1 . Accordingly, the width of the upper housing 1511 may be smaller than the thickness of the sealing part 134 , and in particular, it is preferable that the diameter of the cross-section is 8 mm or less. However, the present invention is not limited thereto, and the housing 151 is not divided into an upper housing 1511 and a lower housing 1512 and may have various shapes, such as having a single cylinder shape.
[68]
The seat 152 is formed inside the housing 151 . In addition, a passage 154 communicating the inside and the outside of the pouch is formed through the center of the sheet 152 . A detailed description of the sheet 152 will be described later.
[69]
The leaf spring 153 is made of metal and opens and closes the passage 154 formed in the sheet 152 according to the internal pressure of the pouch. In particular, when the internal pressure of the pouch is less than a certain pressure, the leaf spring 153 closes the outlet 1541 of the passage 154 . And, when the internal pressure of the pouch gradually increases and exceeds a certain pressure, the leaf spring 153 opens the outlet 1541 of the passage 154 while being spaced apart from the seat 152 .
[70]
Conventionally, the passage was opened and closed using a coil spring. However, in order to be inserted into the sealing part 134 of the secondary battery 1, the venting device needs to be miniaturized. However, if a coil spring is used as in the prior art, the structure of the venting device is complicated and there is a limit to miniaturization. Therefore, according to one embodiment of the present invention, by using the leaf spring 153, the structure of the venting device 15 can be simplified and miniaturized enough to be inserted into the sealing part 134 of the secondary battery 1 . have.
[71]
5 is a schematic view of the venting device 5 in which the ball 55 has a spherical shape.
[72]
The ball 55 is disposed between the leaf spring 53 and the seat 52 , contacts or separates the seat 52 , and opens and closes the passage 54 . However, as shown in FIG. 5 , when the ball 55 has a spherical shape, the state in which the ball 55 contacts the seat 52 to close the passage 54 is relatively to the leaf spring 53 . Despite the state in which the external force acts the least, the leaf spring 53 is greatly bent. Therefore, when the plurality of venting devices 5 are manufactured, there is a problem in that the opening pressure between the plurality of venting devices 5 varies depending on the degree to which the leaf spring 53 is bent. In addition, there was also a problem in that a deviation occurs in the value of the opening pressure designed before the manufacture of the venting device 5 and the actual opening pressure after the manufacture of the venting device 5 .
[73]
Furthermore, since the bent state of the leaf spring 53 is continuously maintained for a long time, a creep phenomenon occurs in the leaf spring 53 to shorten the life of the leaf spring 53 and the entire venting device 5 . There was also the problem of shortening the lifespan of
[74]
6 is a schematic diagram of a sheet 152 in accordance with one embodiment of the present invention.
[75]
The sheet 152 is formed inside the housing 151 , and the passage 154 is formed through it. The sheet 152 may be made of metal to improve durability, but may also be made of polymer to prevent gaps between components. In particular, the polymer may include a polyolefine-based polymer such as polypropylene (PP). As shown in FIG. 6 , the inner peripheral edge of the sheet 152 on the side of the outlet 1541 of the passage 154 is chamfered or filleted.
[76]
7 is a schematic view showing a state in which the ball 155 is seated on the seat 152 according to an embodiment of the present invention.
[77]
According to an embodiment of the present invention, the ball 155 has a hemispherical shape and is disposed on the outlet 1541 side of the passage 154 formed in the seat 152 . Also, it is disposed between the leaf spring 153 and the seat 152 , and contacts or separates the seat 152 to open and close the passage 154 . The ball 155 may be made of a polymer to further improve adhesion to the sheet 152 , but may be made of metal to improve durability of the ball 155 .
[78]
The ball 155 is formed in the shape of a hemisphere and is attached to the inner surface of the leaf spring 153 . At this time, in order to be more easily attached to the leaf spring 153 , a plane other than the hemispherical surface of the ball 155 is attached to the inner surface of the leaf spring 153 . On the other hand, the chamfered or filleted surface 1521 of the sheet 152 has a certain inclination. In addition, as shown in FIG. 7 , the hemispherical surface of the ball 155 faces the ball 155 on one surface 1521 of the seat 152 and can be easily seated.
[79]
In order to be easily seated on the seat 152 , the ball 155 has a diameter smaller than the widest width among the surfaces 1521 of the seat 152 and wider than the narrowest width. And, when the ball 155 is seated, the plane of the ball 155 is formed to have a height substantially similar to the highest point of the seat 152 . Accordingly, since the leaf spring 153 is not greatly bent even when the ball 155 closes the passage 154 , it is possible to reduce the deviation of the opening pressure between the venting devices 15 , and also, the venting device 15 . It is also possible to reduce the deviation between the designed opening pressure value and the actual opening pressure before manufacturing. More preferably, the plane of the ball 155 may be slightly higher than the highest point of the seat 152 . As a result, the elastic force of the leaf spring 153 is efficiently applied to the ball 155 , thereby improving the adhesion of the seat 152 of the ball 155 .
[80]
8 is a schematic diagram of a leaf spring 153 according to an embodiment of the present invention.
[81]
The leaf spring 153 may be manufactured by molding a metal plate. The metal plate has a wide and thin plate shape, is made of metal, and in particular may include aluminum (Al) or stainless steel (STS). And in order to manufacture such a leaf spring 153, the metal plate may be formed by a drawing process of stretching with a punch. Specifically, drawing forming may be performed by seating the metal plate on a die, and then stretching the metal plate with a punch after the stripper fixes the metal plate. As shown in FIG. 8, the leaf spring 153 manufactured in this way has a cap shape with one side portion 1530 convex outward, and an insertion space 1534 into which the seat 152 is inserted. is formed One side portion 1530 of the leaf spring 153 may mean a ceiling in a cap shape, as shown in FIG. 8 . However, the present invention is not limited thereto, and the one side portion 1530 of the leaf spring 153 may include various portions.
[82]
Meanwhile, the leaf spring 153 opens and closes the passage 154 formed in the seat 152 together with the ball 155 according to the internal pressure of the pouch due to the elastic force. To this end, it is preferable that a gas exhaust hole 1533 is perforated in one side portion 1530 of the leaf spring 153 . In this case, one side portion 1530 of the leaf spring 153 includes a central portion 1531 formed in the center and a peripheral portion 1532 extending outwardly from the central portion 1531 . And among the one side portion 1530 , the central portion 1531 has a ball 155 attached to its lower surface to close the passage 154 formed in the seat 152 , so that the central portion 1531 has a gas exhaust hole 1533 . not drilled Accordingly, the gas exhaust hole 1533 is preferably perforated in the peripheral portion 1532 of the one side portion 1530 of the leaf spring 153 .
[83]
The opening pressure of the venting device 15 may be different depending on the shape and area of ​​the gas exhaust hole 1533 . Accordingly, by adjusting the shape and area of ​​the gas exhaust hole 1533 , the opening pressure of the venting device 15 may be adjusted. Here, the opening pressure refers to a specific pressure inside the pouch when the venting device 15 is opened.
[84]
9 is a schematic diagram illustrating a state in which the leaf spring 153 according to an embodiment of the present invention surrounds the seat 152 and the ball 155 .
[85]
When the leaf spring 153 is manufactured, the seat 152 and the ball 155 are inserted into the insertion space 1534 as shown in FIG. 9 . Thereby, the leaf spring 153 surrounds the periphery of the seat 152 and the ball 155 . When the seat 152 and the ball 155 are inserted into the insertion space 1534 , the outlet 1541 side of the passage 154 preferably faces the one side portion 1530 of the leaf spring 153 . Accordingly, when the internal pressure of the pouch is less than a specific pressure, at the outlet 1541 side of the passage 154 formed in the seat 152, one side 1530 of the leaf spring 153 hits the ball 155. By pushing inward, the passageway 154 can be closed.
[86]
The ball 155 is formed in a hemispherical shape, so that a plane, not a hemispherical surface, of the ball 155 is attached to the inner surface of the leaf spring 153 . At this time, an adhesive is applied to the plane of the ball 155 , and when the sheet 152 and the ball 155 are inserted into the insertion space 1534 , the plane of the ball 155 is the center of the leaf spring 153 ( 1531) can be attached to the inner surface. At this time, after the ball 155 is first seated on the seat 152 , it may be inserted into the insertion space 1534 of the leaf spring 153 , but the present invention is not limited thereto. After being attached first, the sheet 152 may be inserted into the insertion space 1534 .
[87]
As described above, a gas exhaust hole 1533 may be formed in a peripheral portion 1532 of one side portion 1530 of the leaf spring 153 . Accordingly, when the gas inside the pouch pushes out one side portion 1530 of the leaf spring 153 , the passage 154 is opened, and the gas flows out to the outlet 1541 of the passage 154 . At this time, the leaked gas should be discharged to the outside through the gas exhaust hole 1533 . Accordingly, the seat 152 may be chamfered (Chamfering) or filleted (Filleting) the outer peripheral edge of the side surface of the outlet 1541 of the passage 154. As a result, the gas can be guided to the gas exhaust hole 1533 , and the peripheral portion 1532 of the one side portion 1530 of the leaf spring 153 is pushed outward while the one side portion 1530 of the leaf spring 153 is pushed outward. ) is provided with a space to move inward.
[88]
10 is a schematic view showing a state in which the other end 1535 of the leaf spring 153 according to an embodiment of the present invention is bent toward the seat 152 side.
[89]
The leaf spring 153 is preferably firmly fixed to the seat 152 . Accordingly, when the gas inside the pouch pushes the one side portion 1530 of the leaf spring 153 outward through the ball 155 , the one side portion 1530 of the leaf spring 153 moves to the outside. At this time, the leaf spring 153 does not slide as a whole, but only one side 1530 of the leaf spring 153 is deformed and moved. This is because, if the leaf spring 153 slides, the leaf spring 153 may leave the venting device 15 . In particular, only the central portion 1531 of the one side portion 1530 is pushed outward, and the peripheral portion 1532 of the one side portion 1530 may move inward. Accordingly, the gas inside the pouch may be discharged to the outside through the passage 154 .
[90]
Therefore, according to an embodiment of the present invention, after the seat 152 and the ball 155 are inserted into the insertion space 1534, the other end 1535 of the leaf spring 153 is removed as shown in FIG. It is bent toward the sheet 152 together. Thereby, even if the gas inside the pouch pushes one side 1530 of the leaf spring 153 to the outside, it prevents detachment (separation) from the seat 152 so that the leaf spring 153 closes the venting device 15 . It can be fixed without detaching.
[91]
11 is a schematic view showing a state of the venting device 15, which is manufactured by inserting the leaf spring 153 and the seat 152 into the housing 151 according to an embodiment of the present invention.
[92]
The leaf spring 153 into which the seat 152 is inserted is inserted into the housing 151 as shown in FIG. 11 . Thereby, the manufacturing of the venting device 15 according to an embodiment of the present invention is completed. The venting device 15 manufactured in this way is inserted into the sealing part 134 of the pouch and sealed together.
[93]
At this time, if the housing 151 includes the upper housing 1511 and the lower housing 1512 , the leaf spring 153 and the seat 152 are preferably included in the upper housing 1511 . And, as shown in FIG. 11 , one side portion 1530 of the leaf spring 153 preferably faces the open end 1513 of the upper housing 1511 . Accordingly, gas may be discharged to the outside through the gas exhaust hole 1533 formed in the one side portion 1530 .
[94]
In addition, as described above, the leaf spring 153 does not slide as a whole, but only one side 1530 is deformed in a fixed state. Accordingly, when the leaf spring 153 is inserted into the housing 151 , in order to exert a large frictional force between the outer circumferential surface of the leaf spring 153 and the inner circumferential surface of the housing 151 , between the leaf spring 153 and the housing 151 . It is desirable that the gap between the However, the present invention is not limited thereto, and in order to further increase the frictional force, the friction coefficient may be increased by increasing the surface roughness of the outer circumferential surface of the leaf spring 153 or the inner circumferential surface of the housing 151 . Furthermore, a separate adhesive may be applied between the leaf spring 153 and the housing 151, or a protrusion may protrude in one of the plate spring 153 and the housing 151 and a groove may be formed in the other to be coupled, etc. The leaf spring 153 may be fixed to the housing 151 in various ways.
[95]
12 is an operation diagram illustrating an operation of the venting device 15 according to an embodiment of the present invention.
[96]
On the other hand, when the secondary battery 1 is stored or stored at a high temperature, the high temperature rapidly promotes an electrochemical reaction between the electrolyte and the electrode active material, and gas may be generated therein.
[97]
When gas is generated inside the pouch and the internal pressure of the pouch gradually increases to exceed a certain pressure, as shown in FIG. 12 , the gas pushes the ball 155 outward, and the ball 155 is pushed out. Accordingly, one side portion 1530 of the leaf spring 153 is also pushed outward. In addition, the leaf spring 153 is spaced apart from the seat 152, and the ball 155 is separated from the seat 152 to open the outlet 1541 of the passage 154, and the gas inside the pouch flows through the passage 154 and It may be discharged to the outside through the gas exhaust hole 1533 . At this time, as described above, it is preferable that the leaf spring 153 does not slide with respect to the seat 152 .
[98]
When the gas inside the pouch is sufficiently discharged to the outside, the internal pressure of the pouch is reduced again, so that the pressure of the gas pushing the leaf spring 153 is reduced. However, the leaf spring 153 is made of metal and has elasticity. Accordingly, when the internal pressure of the pouch becomes smaller than a specific pressure, the leaf spring 153 returns to its original position by the elastic force. And, the elastic force of the leaf spring 153 pushes the ball 155 inward from the exit 1541 side of the passage 154 formed in the seat 152 , and the ball 155 is one surface of the seat 152 . Close the outlet 1541 of the passage 154 while closely adhering to the 1521 .
[99]
13 is a schematic diagram showing a state in which the manufacturing of the venting device 15a according to another embodiment of the present invention is completed.
[100]
According to an embodiment of the present invention, the leaf spring 153 has a cap shape in which one side portion 1530 is convex outward, and a seat 152 and a ball 155 are placed in the insertion space 1534 formed therein. this is inserted However, since the leaf spring 153 has a cap shape, it may not be easy to attach the plane of the ball 155 to an accurate position on the inner surface of the leaf spring 153 .
[101]
Accordingly, in the venting device 15a according to another embodiment of the present invention, as shown in FIG. 13 , the leaf spring 153a has a flat plate shape and contacts the seat 152a. In addition, a separate fixing ring (not shown) may be inserted into the upper housing 1511 and fixed to the upper portion of the leaf spring 153a. The fixing ring has elasticity, and when it is inserted into the upper housing 1511, an external force is applied to decrease the diameter, and after being inserted into the upper housing 1511, the external force is removed and the diameter can increase again have. Accordingly, when the elastic force acts as a normal force on the inner circumferential surface of the upper housing 1511 , the frictional force between the fixing ring and the inner circumferential surface of the upper housing 1511 may increase.
[102]
Therefore, according to another embodiment of the present invention, the ball 155 can be easily attached to the correct position on the inner surface of the central portion 1531a of the leaf spring 153a, and the leaf spring 153a is installed with a separate fixing ring. It can be easily fixed to the inside of the upper housing 1511 .
[103]
14 is an operation diagram illustrating an operation of the venting device 15a according to another embodiment of the present invention.
[104]
In the venting device 15a according to another embodiment of the present invention, when the internal pressure of the pouch exceeds a specific pressure, as shown in FIG. 14 , the gas pushes the ball 155 outward, and the ball ( As the 155 is pushed out, the leaf spring 153a is also pushed outward. And the leaf spring 153a is spaced apart from the seat 152a, and the ball 155 is separated from the seat 152a to open the outlet 1541 of the passage 154, and the gas inside the pouch flows through the passage 154 and The gas may be discharged to the outside through the gas exhaust hole 1533a.
[105]
When the gas inside the pouch is sufficiently discharged to the outside, the internal pressure of the pouch decreases again, so that the pressure of the gas pushing the leaf spring 153a is reduced. Accordingly, when the internal pressure of the pouch becomes smaller than the specific pressure, the leaf spring 153a returns to its original position by the elastic force. Then, the elastic force of the leaf spring 153a pushes the ball 155 inward from the outlet 1541 side of the passage 154 formed in the seat 152a, and the ball 155 is one surface of the seat 152a. Close the outlet 1541 of the passage 154 while closely adhering to the 1521 .
[106]
Those of ordinary skill in the art to which the present invention pertains will understand that the present invention may be embodied in other specific forms without changing the technical spirit or essential features thereof. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims rather than the above detailed description, and various embodiments derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.
Claims
[Claim 1]
A venting device inserted into a sealing part of a pouch of a secondary battery, comprising: a housing inserted between both surfaces of the sealing part and sealed together with the sealing part; a sheet formed inside the housing and through which a passage communicating the inside and the outside of the pouch is formed; a leaf spring which opens and closes the passage according to the internal pressure of the pouch, and is made of metal having elastic force; and a ball disposed between the seat and the leaf spring, at the outlet side of the passage, contacting or spaced apart from the seat to open and close the passage, wherein the ball is formed in a hemispherical shape and the leaf spring A venting device that is attached to the inner surface of the
[Claim 2]
According to claim 1, wherein the leaf spring, a central portion formed in the center; and a peripheral portion extending outwardly from the central portion, wherein the ball is attached to the central portion, and a gas exhaust hole is perforated in the peripheral portion.
[Claim 3]
The venting device according to claim 1, wherein the leaf spring has a cap shape with one side convex outward, and an insertion space into which the seat and the ball are inserted.
[Claim 4]
The venting device according to claim 3, wherein the leaf spring has the other end bent toward the seat inserted into the insertion space.
[Claim 5]
The venting device according to claim 1, wherein the leaf spring has a shape of a flat plate and is in contact with the seat.
[Claim 6]
The venting device according to claim 1, wherein the sheet is chamfered or filleted at an inner peripheral edge of the exit side surface of the passage.
[Claim 7]
The venting device according to claim 1, wherein the sheet is chamfered or filleted at an outer peripheral edge of the exit side surface of the passage.
[Claim 8]
The venting device according to claim 1, wherein the housing includes an upper housing and a lower housing having different shapes or sizes from each other.
[Claim 9]
The venting device according to claim 8, wherein the lower housing has a width smaller than a width of the upper housing.
[Claim 10]
The venting device according to claim 8, wherein the upper housing has a circular cylindrical shape, and the lower housing has an elliptical cylindrical shape.
[Claim 11]
A pouch-type secondary battery in which the venting device according to claim 1 is inserted into the sealing portion of the pouch.
[Claim 12]
A battery module comprising the pouch-type secondary battery according to claim 11 as a unit cell.
[Claim 13]
A device comprising the battery module according to claim 12.
[Claim 14]
The method of claim 13, wherein the device is a computer, a notebook computer, a smart phone, a mobile phone, a tablet PC, a wearable electronic device, a power tool, an electric vehicle (EV), a hybrid electric vehicle, HEV), a Plug-in Hybrid Electric Vehicle (PHEV), or a device that is a power storage device.