Specification
Title of the invention: Venting device and manufacturing method thereof
Technical field
[One]
Mutual citation with related applications
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0069451 filed on June 18, 2018, and all contents disclosed in the documents of the Korean patent application are included as part of this specification.
[3]
Technical field
[4]
The present invention relates to a venting device and a method of manufacturing the same, and more particularly, at least one is inserted into a sealing portion of a pouch of a secondary battery, and when the internal pressure of the pouch increases, the internal gas is discharged to the outside to control the pressure. It relates to a venting device and a method of manufacturing the same.
Background
[5]
In general, types of secondary batteries include nickel cadmium batteries, nickel hydride batteries, lithium ion batteries and lithium ion polymer batteries. These secondary batteries are not only small products such as digital cameras, P-DVDs, MP3Ps, mobile phones, PDAs, portable game devices, power tools, and E-bikes, but also large products requiring high output such as electric vehicles and hybrid vehicles, and surplus power generation. It is also applied and used in power storage devices for storing electric power or renewable energy and power storage devices for backup.
[6]
Secondary batteries are classified into pouch type and can type, depending on the material of the case accommodating the electrode assembly. The pouch type accommodates the electrode assembly in a pouch made of a soft polymer material. In addition, the can type accommodates the electrode assembly in a case made of a material such as metal or plastic.
[7]
Meanwhile, in the secondary battery, gas may be generated due to an internal short circuit, overcharging, or overdischarging due to an external shock. Alternatively, when stored or stored at a high temperature, gas may be generated by rapidly accelerating the electrochemical reaction of the electrolyte and the electrode active material.
[8]
In this case, the generated gas raises the internal pressure of the secondary battery, causing problems such as weakening of bonding force between parts, damage to the case of the secondary battery, premature operation of the protection circuit, deformation of the electrode, internal short circuit, and explosion. To prevent this, in the case of a can-type secondary battery, a protective member such as a CID filter and a safety vent is provided. Therefore, when the pressure inside the case increases, the electrical connection is physically cut off. However, in the case of a conventional pouch type secondary battery, such a protective member is not sufficiently provided.
Detailed description of the invention
Technical challenge
[9]
The problem to be solved by the present invention is inserted into at least one of the sealing portion of the pouch of the secondary battery, and when the internal pressure of the pouch increases, a venting device capable of adjusting the pressure by discharging the internal gas to the outside and a manufacturing method thereof are provided. Is to do.
[10]
The problems of the present invention are not limited to the problems mentioned above, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.
Means of solving the task
[11]
A venting device according to an embodiment of the present invention for solving the above problem is a venting device inserted into a sealing part of a pouch of a secondary battery, which is inserted between both sides of the sealing part and sealed together with the sealing part. A housing made of; A gasket made of a polymer, formed inside the housing, and having a passage communicating inside and outside the pouch through which a passage is formed; And a leaf spring made of metal and opening and closing the passage according to the internal pressure of the pouch, and the housing includes a crimping portion formed on an upper end and crimped together with the gasket.
[12]
In addition, the gasket may include a lower gasket through which the passage is formed; And an upper gasket having the same outer diameter as the lower gasket, extending upward from the lower gasket, having a relatively thin thickness compared to the lower gasket, and crimping together when the crimping portion is crimped.
[13]
In addition, the leaf spring, the center formed in the center; And a peripheral portion extending outwardly from the central portion, and a gas exhaust hole may be perforated in the peripheral portion.
[14]
Further, the crimping portion may be crimped while pressing the peripheral portion of the leaf spring.
[15]
In addition, it may further include a ball disposed between the gasket and the leaf spring, contacting or spaced apart from the gasket at the outlet side of the passage to open and close the passage.
[16]
In addition, the gasket may be chamfered or filleted at an inner peripheral edge of an outlet side surface of the passage.
[17]
In addition, the housing may include an upper housing and a lower housing having different shapes or sizes from each other.
[18]
In addition, the lower housing may have a width smaller than that of the upper housing.
[19]
In addition, the upper housing may have a circular cylinder shape, and the lower housing may have an elliptical cylinder shape.
[20]
In addition, the gasket may be inserted into the upper housing.
[21]
In the method of manufacturing a venting device according to an embodiment of the present invention for solving the above problem, in a method of manufacturing a venting device inserted into a sealing portion of a pouch of a secondary battery, by forming a metal plate, including an insertion space therein. Manufacturing the housing; Installing a leaf spring for opening and closing the passage according to the internal pressure of the pouch in a gasket through which passages communicating inside and outside of the pouch are formed; Inserting the gasket with the leaf spring installed into the insertion space of the housing; And crimping the crimping portion formed on the top of the housing.
[22]
In addition, in the step of manufacturing the housing, the housing may be manufactured by molding the metal plate by a drawing process of stretching the metal plate with a punch.
[23]
In addition, the drawing process may include a first drawing process of stretching the metal plate material with a first punch; And a second drawing process of stretching the metal plate with a second punch having a diameter smaller in cross section than the first punch.
[24]
In addition, the first punch may have a circular cross section, and the second punch may have an elliptical cross section.
[25]
In addition, in the step of installing the leaf spring, a ball may be further installed between the gasket and the leaf spring, contacting or spaced apart from the gasket at the outlet side of the passage, and opening and closing the passage.
[26]
Other specific details of the present invention are included in the detailed description and drawings.
Effects of the Invention
[27]
According to the embodiments of the present invention, there are at least the following effects.
[28]
By drawing and molding the metal plate, the housing of the venting device is manufactured, and since the crimping portion formed on the top of the housing is crimped, the venting device can be manufactured quickly and economically, and the sealing property can be excellent.
[29]
In addition, since the outer wall thickness of the housing of the venting device can be made thin, the venting device can be further miniaturized.
[30]
The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the specification.
Brief description of the drawing
[31]
1 is an assembly diagram of a secondary battery including a venting device according to an embodiment of the present invention.
[32]
FIG. 2 is a perspective view of the secondary battery of FIG. 1 that has been manufactured.
[33]
3 is a partial cross-sectional view of a battery case according to an embodiment of the present invention.
[34]
4 is a perspective view of a venting device according to an embodiment of the present invention.
[35]
5 is a flowchart of a method of manufacturing a venting device according to an embodiment of the present invention.
[36]
6 is a schematic diagram showing a metal plate on which a first drawing molding is performed according to an embodiment of the present invention.
[37]
7 is a schematic diagram showing a metal plate on which a second drawing molding is performed according to an embodiment of the present invention.
[38]
8 is a schematic view showing a metal plate material on which drawing molding is completed according to an embodiment of the present invention.
[39]
9 is a perspective view of a housing manufactured by extracting only a drawing-molded part from a metal plate according to an embodiment of the present invention.
[40]
10 is a side cross-sectional view of a gasket according to an embodiment of the present invention.
[41]
11 is a side cross-sectional view showing a state in which a ball and a leaf spring are installed in a gasket according to an embodiment of the present invention.
[42]
12 is a side cross-sectional view showing a state in which a gasket is inserted into a housing according to an embodiment of the present invention.
[43]
13 is a side cross-sectional view showing a state in which crimping is performed on a crimping portion formed at the top of a housing according to an embodiment of the present invention.
[44]
14 is a side cross-sectional view of a venting device according to an embodiment of the present invention.
[45]
15 is a side cross-sectional view of a venting device according to another embodiment of the present invention.
Mode for carrying out the invention
[46]
Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, and only these embodiments make the disclosure of the present invention complete, and are common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.
[47]
Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used as meanings commonly understood by those skilled in the art to which the present invention pertains. In addition, terms defined in the commonly used dictionary are not ideally or excessively interpreted unless specifically defined.
[48]
The terms used in the present specification are for describing exemplary embodiments and are not intended to limit the present invention. In the present specification, the singular form also includes the plural form unless specifically stated in the phrase. As used herein, “comprises” and/or “comprising” do not exclude the presence or addition of one or more other elements other than the mentioned elements.
[49]
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[50]
FIG. 1 is an assembly view of a secondary battery 1 including a venting device 15 according to an exemplary embodiment of the present invention, and FIG. 2 is a perspective view of the secondary battery 1 of FIG. 1 that has been manufactured.
[51]
In order to manufacture the secondary battery 1 according to an embodiment of the present invention, first, an electrode active material slurry is applied to a positive electrode current collector and a negative electrode current collector to prepare a positive electrode and a negative electrode, and then stacked on both sides of a separator. Thus, the electrode assembly 10 having a predetermined shape is formed. Then, the electrode assembly 10 is accommodated in the battery case 13, and the electrolyte is injected and then sealed.
[52]
The electrode assembly 10 includes an electrode tab 11, as shown in FIG. 1. The electrode tabs 11 are respectively connected to the positive electrode and the negative electrode of the electrode assembly 10, protrude to the outside of the electrode assembly 10, and become a path through which electrons can move between the inside and the outside of the electrode assembly 10. . The electrode current collector of the electrode assembly 10 includes a portion to which the slurry is applied and an end portion to which the slurry is not applied, that is, an uncoated portion. Further, the electrode tab 11 may be formed by cutting the uncoated portion or by connecting a separate conductive member to the uncoated portion by ultrasonic welding or the like. 1, the electrode tabs 11 may protrude side by side in the same direction from one side of the electrode assembly 10, but are not limited thereto and may protrude in different directions.
[53]
An electrode lead 12 is connected to the electrode tab 11 of the electrode assembly 10 by spot welding or the like. Then, a part of the electrode lead 12 is surrounded by the insulating portion 14. The insulating portion 14 is located limited to the sealing portion 134 in which the upper pouch 131 and the lower pouch 132 of the battery case 13 are heat-sealed, so that the electrode lead 12 is attached to the battery case 13. Bond. 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 non-conductor that does not conduct electricity well. In general, as the insulating portion 14, an insulating tape that is easy to attach to the electrode lead 12 and has a relatively thin thickness is often used. have.
[54]
The electrode leads 12 may extend in the same direction to each other or in opposite directions depending on the formation positions of the anode tab 111 and the cathode tab 112. The anode lead 121 and the cathode lead 122 may have different materials. 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 the same copper (Cu) material or nickel (Ni) coated copper material as the negative electrode current collector. In addition, 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.
[55]
In the pouch-type secondary battery 1 according to an embodiment of the present invention, the battery case 13 is a pouch made of a flexible material. Hereinafter, the battery case 13 will be described as being a pouch. In addition, the battery case 13 accommodates and seals the electrode assembly 10 so that a part of the electrode lead 12, that is, the terminal portion is exposed. The battery case 13 includes an upper pouch 131 and a lower pouch 132 as shown in FIG. 1. The lower pouch 132 has a cup portion 133 provided with an accommodation space 1331 capable of accommodating the electrode assembly 10, and the upper pouch 131 includes the electrode assembly 10 of the battery case 13. The accommodation space 1331 is covered from the top so as not to be separated from the outside. In this case, as shown in FIG. 1, a cup portion 133 in which an accommodation space 1331 is provided is also formed in the upper pouch 131, so that the electrode assembly 10 may be accommodated from the top. As shown in FIG. 1, the upper pouch 131 and the lower pouch 132 may be manufactured by connecting one side to each other, but are not limited thereto and may be manufactured in various ways such as being separated from each other and manufactured separately.
[56]
After the upper pouch 131 and the lower pouch 132 of the battery case 13 come into contact with each other, the sealing portion 134 formed on the rim 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 unit 134 and sealed together, thereby being fixed within the sealing unit 134. do. And the venting device 15 includes a passage 154 that communicates the inside and the outside of the battery case 13 to each other, and when the internal pressure of the battery case 13 increases, the internal gas is discharged to the outside to control the pressure. do. Details of the venting device 15 will be described later.
[57]
When the electrode lead 12 is connected to the electrode tab 11 of the electrode assembly 10 and the insulating part 14 is formed in a part of the electrode lead 12, the accommodation space 1331 provided in the lower pouch 132 In the electrode assembly 10 is accommodated, and the upper pouch 131 covers the receiving space 1331 from the top. Then, when an electrolyte is injected into the interior and the sealing portions 134 formed on the edges of the upper pouch 131 and the lower pouch 132 are sealed, the secondary battery 1 is manufactured as shown in FIG. 2.
[58]
3 is a partial cross-sectional view of a battery case 13 according to an embodiment of the present invention.
[59]
The battery case 13 is manufactured by drawing the pouch film 135. That is, it is manufactured by stretching the pouch film 135 to form the cup portion 133. As shown in FIG. 3, the pouch film 135 includes a gas barrier layer 1351, a surface protection layer 1352, and a sealant layer 1353.
[60]
The gas barrier layer 1351 secures the mechanical strength of the battery case 13, blocks entry of gas or moisture from the secondary battery 1, and prevents leakage of an electrolyte. In general, the gas barrier layer 1351 includes metal, and an aluminum thin film (Al Foil) is mainly used. Although aluminum can secure a mechanical strength of a predetermined level or higher, it is light in weight, and supplementation of electrochemical properties by the electrode assembly 10 and the electrolyte and heat dissipation properties can be secured. 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 a material containing iron, mechanical strength is improved, and when it is made of a material containing aluminum, flexibility is improved, so it may be used in consideration of each characteristic.
[61]
The surface protection layer 1352 is made of a polymer and is positioned on the outermost layer to protect the secondary battery 1 from friction and collision with the outside, while electrically insulating the electrode assembly 10 from the outside. Here, the outermost layer refers to a direction opposite to the direction in which the electrode assembly 10 is positioned with respect to the gas barrier layer 1351 and to the outside. The surface protection 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 one or more materials selected from the group consisting of phenylenebenzobisoxazole, polyarylate, Teflon, and glass fibers. 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 may have a composite layer structure formed by each layer of two or more materials.
[62]
The sealant layer 1352 is made of a polymer, and is positioned on the innermost layer to directly contact the electrode assembly 10. When the pouch-type battery case 13 is formed by drawing the pouch film 135 of the laminated structure as described above using a punch, etc., a portion of the pouch-type battery case 13 is stretched to include a pocket-shaped receiving space 1331 ( 133). In addition, when the electrode assembly 10 is accommodated in the receiving space 1331, an electrolyte is injected. Thereafter, when the upper pouch 131 and the lower pouch 132 are brought into contact with each other and thermally compressed to the sealing portion 134, the sealant layers 1351 are adhered to each other, thereby sealing the battery case 13. At this time, since the sealant layer 1352 directly contacts the electrode assembly 10, it must have insulating properties, and since it also contacts the electrolyte, it must have corrosion resistance. In addition, since the inside must be completely sealed to block material movement between the inside and outside, it must have high sealing properties. That is, the sealing portion 134 adhered to the sealant layer 1351 should have excellent thermal adhesive strength. In general, the sealant layer 1352 includes polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly It may be made of one or more materials selected from the group consisting of paraphenylenebenzobisoxazole, polyarylate, Teflon, and glass fibers. In particular, polyolefin resins such as polypropylene (PP) or polyethylene (PE) are mainly used. Polypropylene (PP) has tensile strength, stiffness, surface hardness, abrasion resistance, It is excellent in mechanical properties such as heat resistance and chemical properties such as corrosion resistance, and is mainly used to manufacture the sealant layer 1351. Furthermore, it may be composed of a non-stretched polypropylene or a polypropylene-butylene-ethylene terpolymer. In addition, the sealant layer 1352 may have a single film structure made of any one material, or a composite film structure formed by each of two or more materials as a layer.
[63]
4 is a perspective view of a venting device 15 according to an embodiment of the present invention.
[64]
As described above, the secondary battery 1 according to the exemplary embodiment of the present invention further includes at least one venting device 15. At least one venting device 15 is inserted into the sealing part 134 of the pouch of the secondary battery 1, and when the internal pressure of the pouch increases, the internal gas is discharged to the outside to adjust the pressure. To this end, the venting device 15 includes a housing 151 inserted between both surfaces of the sealing part 134 and sealed together with the sealing part 134, and made of a metal plate 2; A gasket 152 formed of a polymer, formed inside the housing 151, and formed with a passage 154 communicating therein and outside the pouch; And a leaf spring 153 made of metal to open and close the passage 154 according to the internal pressure of the pouch. In addition, the housing 151 includes a crimping portion 1514 formed on an upper end and crimped together with the gasket 152.
[65]
In addition, the venting device 15 is disposed between the gasket 152 and the leaf spring 153, at the outlet side of the passage 154, in contact with or spaced apart from the gasket 152, and the passage 154 ) May further include a ball 155 for opening and closing.
[66]
The housing 151 is inserted between both sides of the sealing part 134 and sealed together with the sealing part 134, and is made of a metal plate 2. When the housing 151 is inserted into both surfaces of the sealing portion 134, the sealant layer 1352, which is the innermost layer of the sealing portion 134, and the housing 151 contact each other. In addition, when heat and pressure are applied, the sealant layer 1351 of the sealing portion 134 is sealed, and the housing 151 may be fused together to be sealed. As illustrated in FIG. 4, 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. This step may be formed when the upper housing 1511 and the lower housing 1512 have different shapes or sizes from each other. For example, the upper housing 1511 may have a circular cylinder shape due to a cross section, and the lower housing 1512 may have an elliptical cylinder shape whose cross section is an ellipse. Alternatively, the width of the lower housing 1512 may be smaller than the width of the upper housing 1511. Therefore, the lower housing 1512 is inserted between both surfaces of the sealing portion 134 and sealed together, so that the inner surface of the sealing portion 134 is fused, and the upper housing 1511 may protrude outward of the pouch.
[67]
In this case, if the width of the lower housing 1512 is excessively large, the sealing portion 134 must also be greatly deformed, and thus the sealing of the sealing portion 134 is likely to be destroyed. Accordingly, the width of the lower housing 1512 may be smaller than the thickness of the sealing portion 134, and in particular, it is preferable that the long axis of the cross section is 6 mm or less. And, as described above, the lower housing 1512 has an oval cylinder shape with an ellipse in cross section, so that the lower housing 1512 is easily sealed to the sealing unit 134, so that the sealing can be maintained without breaking for a long period of time. have.
[68]
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 secondary batteries 1 in the vicinity. As a result, 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 also be smaller than the thickness of the sealing portion 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 may have various shapes, such as having a single cylinder shape without being divided into an upper housing 1511 and a lower housing 1512.
[69]
The gasket 152 (shown in FIG. 10) is made of a polymer, and is formed in the housing 151. In addition, the gasket 152 has a passage 154 that communicates the inside and the outside of the pouch through the center. A detailed description of the gasket 152 will be described later.
[70]
The leaf spring 153 is made of metal and opens and closes the passage 154 formed in the gasket 152 according to the internal pressure of the pouch. In particular, when the internal pressure of the pouch is less than a specific pressure, the leaf spring 153 contacts the gasket 152 to close the outlet 1541 (shown in FIG. 10) of the passage 154. Then, when the internal pressure of the pouch gradually increases and exceeds a specific pressure, the leaf spring 153 partially opens the outlet 1541 of the passage 154 while being separated from the gasket 152. As shown in FIG. 4, the leaf spring 153 includes a central portion 1531, a peripheral portion 1532, and a gas exhaust hole 1533. The detailed description of the leaf spring 153 will be described later.
[71]
The crimping portion 1514 is formed on the upper end of the housing 151 and is crimped together with the gasket 152 to prevent separation of the leaf spring 153 and the ball 155 (shown in FIG. 11 ). A detailed description of the crimping portion 1514 will be described later.
[72]
5 is a flowchart of a method of manufacturing a venting device 15 according to an embodiment of the present invention.
[73]
Meanwhile, according to an embodiment of the present invention, the metal plate 2 is drawn and molded to manufacture the housing 151 of the venting device 15, and the crimping portion 1514 formed on the upper end of the housing 151 is crimped. Therefore, the venting device 15 can be manufactured quickly and economically, and the sealing property can be excellent. In addition, since the outer wall thickness of the housing 151 of the venting device 15 can be made thin, the venting device 15 can be further miniaturized. To this end, the method of manufacturing the venting device 15 according to an embodiment of the present invention inserted into the sealing part 134 of the pouch of the secondary battery 1 is to form a metal plate 2 and insert a space therein. Manufacturing the housing 151 including the 1513 (S501); Step of installing a leaf spring 153 for opening and closing the passage 154 according to the internal pressure of the pouch in the gasket 152 through which the passage 154 communicating inside and outside the pouch is formed (S502) ; Inserting the gasket 152 on which the leaf spring 153 is installed into the insertion space 1513 of the housing 151 (S503); And crimping the crimping portion 1514 formed on the upper end of the housing 151 (S504).
[74]
In the step of manufacturing the housing 151, the housing 151 is manufactured by molding the metal plate 2 by a drawing process of stretching with a punch, and the drawing process includes the metal plate 2 A first drawing step of stretching with a first punch; And a second drawing process of stretching the metal plate 2 with a second punch having a diameter smaller than that of the first punch.
[75]
Hereinafter, each step shown in the flowchart of FIG. 5 will be described with reference to FIGS. 6 to 14.
[76]
6 is a schematic view showing a metal plate 2 in which first drawing molding is performed according to an embodiment of the present invention.
[77]
As shown in FIG. 6, the metal plate 2 has a wide and thin plate shape, is made of metal, and may include aluminum (Al) or stainless steel (STS). And according to an embodiment of the present invention, the housing 151 is manufactured by molding the metal plate 2 (S508). In order to manufacture the housing 151, the metal plate 2 may be molded in a drawing process in which a punch is drawn. Furthermore, according to an embodiment of the present invention, drawing molding may be performed multiple times, particularly twice, on the metal plate 2. Specifically, first drawing molding may be performed by mounting the metal plate 2 on a die, fixing the metal plate 2 by a stripper, and then stretching with a first punch.
[78]
7 is a schematic diagram showing a metal plate 2 on which a second drawing molding is performed according to an embodiment of the present invention.
[79]
When the first drawing molding is performed on the metal plate 2 as described above, the upper housing 1511 is formed as shown in FIG. 7. The upper housing 1511 has a shape of a cup 155 in which the lower side is outwardly convex, and includes an insertion space 1513 into which the gasket 152 is inserted.
[80]
As described above, the drawing molding may be performed on the metal plate 2 a plurality of times, in particular twice. Therefore, when the first drawing process is completed, the lower surface of the upper housing 1511 is seated on the die again, the stripper fixes the upper housing 1511 of the metal plate 2, and then stretches it with a second punch. 2 Drawing molding can be performed.
[81]
8 is a schematic view showing a metal plate 2 on which drawing molding is completed according to an embodiment of the present invention.
[82]
When the second drawing molding is performed as described above, the lower housing 1512 is formed as shown in FIG. 8. The lower housing 1512 is formed from the lower surface of the upper housing 1511, and the lower housing 1511 has a cup shape with a ball 155 convex outward like the upper housing 1511, and a passage 154 is formed therein. .
[83]
The second punch used for the second drawing molding may have a smaller cross-sectional diameter than the first punch used for the first drawing molding. Accordingly, as described above, a step may be formed between the upper housing 1511 and the lower housing 1512, and in particular, the width of the lower housing 1512 may be smaller than the width of the upper housing 1511. In addition, the first punch may have a circular cross section, and the second punch may have an elliptical cross section. Accordingly, as described above, the upper housing 1511 may have a circular cylinder shape due to a cross section, and the lower housing 1512 may have an elliptical cylinder shape whose cross section is an ellipse.
[84]
According to an embodiment of the present invention, the lower housing 1512 has an outer sealed portion 134 and an inner portion extends a passage 154 formed in the gasket 152. That is, the interior of the lower housing 1512 also becomes a part of the passage 154. In addition, when perforating work is performed on the bottom surface of the molded housing 151, an inlet of the passage 154 is formed, so that gas inside the pouch may flow into the passage 154 through the inlet.
[85]
However, the present invention is not limited thereto, and the housing 151 may not include the upper housing 1511 and the lower housing 1512, and may itself have a cylindrical shape that does not include a step difference. To this end, drawing molding on the metal plate 2 with only one punch may be performed only once or may be performed multiple times. As a result, since drawing molding is performed with only one punch, there is no need to readjust the die and the stripper, thereby saving the manufacturing time of the venting device 15. In this case, if the cross section of the punch is circular, the housing 151 also has a circular cylinder shape, and if the cross section of the punch is elliptical, the housing 151 also has an elliptical cylinder shape. However, as described above, in order to ensure that the housing 151 is easily sealed to the sealing portion 134 and the sealing is not destroyed for a long period of time, by using a punch having an elliptical cross section, the housing 151 has an elliptical cross section. It is preferred to have an elliptical cylinder shape.
[86]
9 is a perspective view of a housing 151 manufactured by extracting only a drawing-molded part from a metal plate 2 according to an embodiment of the present invention.
[87]
When the drawing molding is completed in the metal plate 2, the metal plate 2 includes a drawing-molded part and the remaining unformed part. At this time, by removing the remaining unmolded portion and extracting only the drawing-molded portion, the housing 151 is manufactured as shown in FIG. 9 (S501).
[88]
This housing 151 includes a crimping portion 1514 at the top. The crimping portion 1514 is formed on the upper end of the housing 151, particularly the upper housing 1511, and is crimped together with the gasket 152, thereby preventing the leaf spring 153 and the ball 155 from being separated. Here, crimping refers to bending the crimping portion 1514 so that the crimping portion 1514 and the gasket 152 seal the outer surface of the leaf spring 153.
[89]
If a separate plate is inserted above the leaf spring 153, the outer circumferential surface of the plate presses the inner wall of the housing 151 to generate a frictional force, thereby preventing separation of the leaf spring 153 and the ball 155. . However, since the leaf spring 153 is also made of metal and the plate is also made of metal, a gap exists between the leaf spring 153 and the plate, so that moisture infiltrates into it. Accordingly, according to the exemplary embodiment of the present invention, the crimping portion 1514 is crimped together with the gasket 152 so that moisture may not penetrate into the venting device 15.
[90]
According to an embodiment of the present invention, without using a cutting process such as lathe or milling, the metal plate 2 is drawn by drawing to manufacture the housing 151 of the venting device 15, and a separate plate is inserted. There is no need to, the crimping portion 1514 formed on the upper end of the housing 151 is crimped. Therefore, the venting device 15 can be manufactured quickly and economically, and the sealing property can be excellent. In addition, since the outer wall thickness of the housing 151 of the venting device 15 can be made thin, the venting device 15 can be further miniaturized.
[91]
10 is a side cross-sectional view of a gasket 152 according to an embodiment of the present invention.
[92]
The gasket 152 is made of a polymer, and is formed inside the housing 151. In particular, it is preferably made of a material having insulation, impact resistance, elasticity and durability, for example, a polyolefine-based polymer such as polypropylene (PP) or polyethylene (PE). As shown in FIG. 10, the gasket 152 has the same outer diameter as the lower gasket 1522 and the lower gasket 1522 through which the passage 154 is formed, and extends upward from the lower gasket 1522. And, the thickness is relatively thin compared to the lower gasket 1522, and includes an upper gasket 1521 that is crimped together when the crimping portion 1514 is crimped. Such a gasket 152 may be formed by being assembled after the lower gasket 1522 and the upper gasket 1521 are separately manufactured from each other, but the lower gasket 1522 and the upper gasket 1521 are manufactured integrally from the beginning. desirable.
[93]
As described above, if the housing 151 includes the upper housing 1511 and the lower housing 1512, the gasket 152 is preferably inserted into the upper housing 1511. In this case, the lower gasket 1522 has a disk shape, and in order to be easily inserted into the upper housing 1511, the shape and size correspond to the insertion space 1513 formed in the upper housing 1511. That is, if the upper housing 1511 has a circular cylinder shape, the lower gasket 1522 also has a circular disk shape, and if the upper housing 1511 has an elliptical cylinder shape, the lower gasket 1522 is also elliptical. It has a disk shape of. Accordingly, when the lower gasket 1522 is inserted into the upper housing 1511, the outer circumferential surface of the lower gasket 1522 is in close contact with the inner circumferential surface of the upper housing 1511.
[94]
In the lower gasket 1522, a passage 154 communicating inside and outside the pouch is formed through the center. Further, as described above, the passage 154 formed in the lower gasket 1522 extends into the lower housing 1512.
[95]
The upper gasket 1521 has the same outer diameter as the lower gasket 1522, is formed to extend upward from the lower gasket 1522, and is relatively thinner than the lower gasket 1522. Since the upper gasket 1521 has the same outer diameter as the lower gasket 1522, the outer circumferential surface of the upper gasket 1521 and the outer circumferential surface of the lower gasket 1522 are extended without forming a step. Accordingly, when the gasket 152 is inserted into the upper housing 1511, not only the lower gasket 1522 but also the outer peripheral surface of the upper gasket 1521 is in close contact with the inner peripheral surface of the upper housing 1511. In addition, the thickness is relatively thin compared to the lower gasket 1522, and is formed to extend upward. Accordingly, when the crimping portion 1514 formed on the upper end of the upper housing 1511 is crimped, the upper gasket 1521 is also crimped.
[96]
11 is a side cross-sectional view showing a state in which the ball 155 and the leaf spring 153 are installed on the gasket 152 according to an embodiment of the present invention.
[97]
The leaf spring 153 is made of metal and opens and closes the passage 154 formed in the gasket 152 according to the internal pressure of the pouch. Therefore, as shown in FIG. 11, this leaf spring 153 is installed on the provided gasket 152 (S502). In particular, in order for the leaf spring 153 to open and close the passage 154 easily, the leaf spring 153 is preferably installed in contact with the upper surface of the lower gasket 1522 on which the outlet of the passage 154 is formed.
[98]
When the internal pressure of the pouch is less than a certain pressure, the leaf spring 153 contacts the gasket 152 and closes the outlet 1541 of the passage 154. Then, when the internal pressure of the pouch gradually increases and exceeds a specific pressure, the leaf spring 153 partially opens the outlet 1541 of the passage 154 while being separated from the gasket 152.
[99]
Conventionally, the passage 154 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 15 must be miniaturized. However, if a coil spring is used as in the prior art, the structure of the venting device 15 is complicated and there is a limit to miniaturization. Accordingly, according to an exemplary embodiment of the present invention, by using the leaf spring 153, the structure can be simplified and miniaturized enough to be inserted into the sealing portion 134 of the secondary battery 1.
[100]
On the other hand, in order to discharge gas to the outside when the leaf spring 153 opens the passage 154, it is preferable that a gas exhaust hole 1533 is perforated in the leaf spring 153. In this case, the leaf spring 153 includes a central portion 1531 formed at the center and a peripheral portion 1532 extending outwardly from the central portion 1531. And since the central portion 1531 closes the passage 154 formed in the gasket 152, the gas exhaust hole 1533 should not be perforated in the central portion 1531. Therefore, it is preferable that the gas exhaust hole 1533 is perforated in the peripheral portion 1532 of the leaf spring 153. The gas exhaust hole 1533 may have a different opening pressure of the venting device 15 according to the shape and area to be formed. Accordingly, by adjusting the shape and area of ​​the gas exhaust hole 1533, the opening pressure of the venting device 15 can be adjusted. Here, the opening pressure refers to a specific pressure inside the pouch when the venting device 15 is opened.
[101]
According to an embodiment of the present invention, when installing the leaf spring 153 on the gasket 152, as shown in FIG. 11, the ball 155 may also be installed. The ball 155 has a spherical shape and is disposed between the gasket 152 and the leaf spring 153, and is particularly disposed on the outlet 1541 side of the passage 154 formed in the gasket 152. Then, at the outlet 1541 side of the passage 154, the gasket 152 is contacted or separated from the passage 154 to open and close the passage. Specifically, the ball 155 receives an elastic force from the central portion 1531 of the leaf spring 153 toward the gasket 152 side, comes in close contact with the gasket 152 and closes the passage 154. At this time, since the gasket 152 is made of a polymer, the ball 155 is in close contact with the gasket 152 to prevent a gap from occurring and the sealing property from being destroyed. The ball 155 may be made of a polymer to further improve adhesion to the gasket 152, but may be made of metal to improve the durability of the ball 155.
[102]
On the other hand, the gasket 152 may be chamfered (Chamfering) or filleting (Filleting) of the inner circumferential edge of the side of the exit 1541 side of the passage 154. As a result, as shown in FIG. 11, the ball 155 can easily come into close contact with the chamfered or filleted inner peripheral surface 1523 of the gasket 152.
[103]
When gas is generated inside the pouch and the internal pressure of the pouch gradually increases and thus exceeds a specific pressure, the gas pushes the ball 155 outward, and the leaf spring 153 moves outward as the ball 155 is pushed out. Is pushed back. And the leaf spring 153 is spaced apart from the gasket 152, the ball 155 is separated from the gasket 152 to open the outlet 1541 of the passage 154, the gas inside the pouch is the passage 154 And it may be discharged to the outside through the gas exhaust hole (1533).
[104]
The gas inside the pouch is sufficiently discharged to the outside, so that the pressure inside the pouch decreases again. Then, while the pressure of the gas pushing the leaf spring 153 decreases, the leaf spring 153 returns to its original position by elasticity, and pushes the ball 155 back inward. Then, the leaf spring 153 is again in contact with the gasket 152 at the outlet 1541 of the passage 154, and the ball 155 is in close contact with the gasket 152 at the outlet of the passage 154 ( 1541) is closed.
[105]
12 is a side cross-sectional view showing a state in which the gasket 152 is inserted into the housing 151 according to an embodiment of the present invention.
[106]
When the leaf spring 153 is installed on the gasket 152, as shown in FIG. 12, the gasket 152 is inserted into the insertion space 1513 of the housing 151 (S503). In particular, if the housing 151 includes an upper housing 1511 and a lower housing 1512, the gasket 152 is preferably inserted into the upper housing 1511.
[107]
As described above, the lower gasket 1522 has a disk shape. In addition, the upper gasket 1521 has the same outer diameter as the upper gasket 1521 and the lower gasket 1522. Accordingly, when the gasket 152 is inserted into the upper housing 1511, not only the lower gasket 1522 but also the outer peripheral surface of the upper gasket 1521 is in close contact with the inner peripheral surface of the upper housing 1511.
[108]
13 is a side cross-sectional view showing a state in which crimping is performed on the crimping portion 1514 formed on the upper end of the housing 151 according to an embodiment of the present invention, and FIG. 14 is a venting device according to an embodiment of the present invention It is a side cross-sectional view of (15).
[109]
When the gasket 152 is inserted into the insertion space 1513 of the housing 151, the crimping portion 1514 formed on the upper end of the housing 151 is crimped (S504). At this time, the gasket 152 is preferably crimped by mechanical processing, rather than by crimping by chemical or heat treatment, in order to prevent the insulation from deteriorating. To this end, as shown in FIG. 13, the crimping jig 4 descends from the top to the bottom to press the crimping portion 1514 formed on the upper end of the housing 151.
[110]
The lower surface of the crimping jig 4 includes a curved surface depressed inward. Accordingly, the crimping jig 4 induces the crimping portion 1514 of the housing 151 to be bent toward the center of the housing 151. Thus, as shown in FIG. 14, the crimping portion 1514 is bent together with the gasket 152, so that the crimping portion 1514 and the gasket 152 can seal the outer surface of the leaf spring 153. At this time, as described above, the gas exhaust hole 1533 is formed by perforating the peripheral portion 1532 of the leaf spring 153. Accordingly, the crimping portion 1514 is preferably crimped while pressing the peripheral portion 1532 avoiding the gas exhaust hole 1533 so as not to shield the gas exhaust hole 1533 of the leaf spring 153.
[111]
15 is a side cross-sectional view of a venting device 15 according to another embodiment of the present invention.
[112]
According to an embodiment of the present invention, a ball 155 is disposed between the gasket 152 and the leaf spring 153. Accordingly, the ball 155 and the leaf spring 153 open and close the outlet of the passage 154 together. However, as described above, in order to be inserted into the sealing portion 134 of the secondary battery 1, the venting device 15 must be miniaturized. This is because electronic products are gradually miniaturized as technology advances, and the secondary battery 1 installed in these electronic products is also miniaturized. Therefore, it is important to simplify the structure of the venting device 15 and reduce the size as much as possible.
[113]
According to another embodiment of the present invention, in order to further simplify the structure of the venting device 15a, as shown in Fig. 15, the ball 155 is removed. That is, there is no other configuration between the gasket 152a and the leaf spring 153a. Accordingly, according to another embodiment of the present invention, it is possible to further simplify the structure of the venting device 15a and further reduce the size.
[114]
When gas is generated in the pouch and the internal pressure of the pouch gradually increases and thus exceeds a specific pressure, the gas does not pass through the ball 155 and directly pushes the leaf spring 153a. And the leaf spring 153a is spaced apart from the gasket 152a to open the outlet 1541 of the passage 154, and the gas inside the pouch is discharged to the outside through the passage 154 and the gas exhaust hole 1533. Can be.
[115]
The gas inside the pouch is sufficiently discharged to the outside, so that the pressure inside the pouch decreases again. Then, while the pressure of the gas pushing the leaf spring 153a decreases, the leaf spring 153a returns to its original position by elasticity. Then, the leaf spring 153a does not pass through the ball 155, and closes the outlet 1541 of the passage 154 while coming into contact with the gasket 152a at the exit 1541 side of the passage 154 again.
[116]
According to another embodiment of the present invention, since the ball 155 does not exist, the central portion 1531a of the leaf spring 153a is formed flat without being bent upward, as shown in FIG. 15. In addition, the inner circumferential edge of the passage 154 of the gasket 152a may not be chamfered or filleted. Therefore, according to another embodiment of the present invention, the process of bending the central portion 1531a of the leaf spring 153a and the inner circumferential edge of the passage 154 of the gasket 152a are chamfered or filleted. Since the process of doing so may be omitted, the method of manufacturing the venting device 15a may also be simplified.
[117]
Those of ordinary skill in the art to which the present invention pertains will appreciate that the present invention can be implemented 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 claims to be described later rather than the 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 portion of a pouch of a secondary battery, comprising: a housing which is inserted between both sides of the sealing portion and sealed together with the sealing portion, and is made of a metal plate; A gasket made of a polymer, formed inside the housing, and having a passage communicating inside and outside the pouch through which a passage is formed; And a leaf spring made of metal and opening and closing the passage according to an internal pressure of the pouch, wherein the housing includes a crimping portion formed on an upper end and crimped together with the gasket.
[Claim 2]
The apparatus of claim 1, wherein the gasket comprises: a lower gasket through which the passage is formed; And an upper gasket having the same outer diameter as the lower gasket, extending upwardly from the lower gasket, having a relatively thin thickness compared to the lower gasket, and crimping together when the crimping portion is crimped. .
[Claim 3]
According to claim 1, The leaf spring, Central formed in the center; And a peripheral portion extending in an outward direction from the central portion, wherein a gas exhaust hole is perforated in the peripheral portion.
[Claim 4]
The venting device according to claim 3, wherein the crimping portion is crimped while pressing the peripheral portion of the leaf spring.
[Claim 5]
The venting device according to claim 1, further comprising a ball disposed between the gasket and the leaf spring and contacting or spaced apart from the gasket at the outlet side of the passage and opening and closing the passage.
[Claim 6]
The venting device according to claim 5, wherein the gasket has a chamfered or filleted inner circumferential edge of an outlet side surface of the passage.
[Claim 7]
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 8]
The venting device according to claim 7, wherein the lower housing has a width smaller than that of the upper housing.
[Claim 9]
The venting device according to claim 7, wherein the upper housing has a circular cylinder shape, and the lower housing has an elliptical cylinder shape.
[Claim 10]
The venting device of claim 9, wherein the gasket is inserted into the upper housing.
[Claim 11]
A method of manufacturing a venting device inserted into a sealing portion of a pouch of a secondary battery, the method comprising: forming a metal plate to produce a housing including an insertion space therein; Installing a leaf spring for opening and closing the passage according to the internal pressure of the pouch in a gasket through which passages communicating inside and outside of the pouch are formed; Inserting the gasket with the leaf spring installed into the insertion space of the housing; And crimping the crimping portion formed on the upper end of the housing.
[Claim 12]
The method of claim 11, wherein in the manufacturing of the housing, the housing is manufactured by molding the metal plate by a drawing process of stretching the metal plate with a punch.
[Claim 13]
The method of claim 12, wherein the drawing step comprises: a first drawing step of stretching the metal plate material with a first punch; And a second drawing step of stretching the metal plate with a second punch having a smaller cross-section diameter than the first punch.
[Claim 14]
The method of claim 13, wherein the first punch has a circular cross section, and the second punch has an elliptical cross section.
[Claim 15]
The method of claim 11, wherein in the step of installing the leaf spring, a ball is further installed between the gasket and the leaf spring, contacting or spaced apart from the gasket at the outlet side of the passage, and opening and closing the passage, Venting device manufacturing method.