KR20190125664A - Cylindrical lithium ion secondary battery - Google Patents

Abstract

Various embodiments of the present invention relate to a secondary battery, and a technical problem to be solved is to provide a secondary battery that can invert a safety vent to block a current path when internal pressure is higher than reference pressure, or blow a fuse to block the current path when charging/discharging current is higher than reference current. To this end, the secondary battery includes: a cylindrical can; an electrode assembly housed in the cylindrical can; and a cap assembly sealing the cylindrical can, wherein the cap assembly includes a cap up bottom plate electrically connected to the electrode assembly, a cap up top plate installed on an upper portion of the cap up bottom plate, a fuse element electrically connecting the cap up bottom plate and the cap up top plate, and an insulating member coupling the cap up bottom plate and the cap up top plate while surrounding the fuse element.

Description

Cylindrical lithium ion secondary battery

Various embodiments of the present invention relate to a cylindrical lithium ion secondary battery.

Lithium ion secondary batteries are used for powering hybrid vehicles or electric vehicles as well as portable electronic devices due to their high operating voltage and high energy density per unit weight.

Such lithium ion secondary batteries may be classified into cylindrical, rectangular, and pouch type secondary batteries. The double cylindrical lithium ion secondary battery generally has a cylindrical electrode assembly, a cylindrical can to which the electrode assembly is coupled, an electrolyte solution injected into the can to allow lithium ions to move, and is coupled to one side of the can. And a cap assembly for preventing leakage of the electrolyte solution and preventing separation of the electrode assembly.

The above-described information disclosed in the background technology of the present invention is only for improving the understanding of the background of the present invention, and thus may include information that does not constitute the prior art.

Various embodiments of the present invention provide a secondary battery capable of blocking the current path by inverting the safety vent when the internal pressure is higher than the reference pressure, and cutting off the fuse when the charge / discharge current is higher than the reference current. .

In addition, various embodiments of the present invention provide a secondary battery that can increase the operating pressure of the safety vent and also improve the high temperature neglect storage characteristics.

Cylindrical lithium ion secondary battery according to various embodiments of the present invention is a cylindrical can; An electrode assembly housed in the cylindrical can; And a cap assembly sealing the cylindrical can, wherein the cap assembly electrically connects a cap up bottom plate electrically connected to the electrode assembly, a cap up top plate installed on an upper portion of the cap up bottom plate, and a cap up bottom plate and the cap up top plate. The fuse device and the insulating member may be coupled to the cap-up lower plate and the cap-up upper plate while surrounding the fuse element.

In this manner, in the embodiment of the present invention, the cap assembly can block the current path not only by the battery breakdown voltage but also by overcurrent, thereby further improving the safety and reliability of the battery.

The cap up lower plate may be formed in a circular disk shape having an opening in the center, and the cap up top plate may be formed in a circular disk shape.

In this manner, the embodiment of the present invention allows the cap up lower plate to be electrically connected to the safety vent, and the cap up top plate to be electrically connected to an external device, so that charging and discharging can be performed smoothly as in a conventional secondary battery.

The fuse device may include a fuse, a lower lead connecting one side of the fuse and the cap up lower plate, and an upper lead connecting the other side of the fuse and the cap up top plate.

As described above, in the embodiment of the present invention, the cap-up lower plate and the cap-up upper plate are electrically connected by the fuse element, so that the fuse element serves as a path of the charge / discharge current under normal charging / discharging conditions, but the cap-up lower plate is caused by the blown fuse during overcurrent. The current path between the cap and the top plate is blocked, thereby improving battery safety and reliability.

The insulating member may be formed in the form of an inverted funnel having a lower end coupled to the cap up lower plate and an upper end coupled to the cap up upper plate.

In this manner, in the embodiment of the present invention, the insulating member is coupled between the cap-up lower plate and the cap-up upper plate, thereby further increasing the operating pressure according to the battery internal pressure.

The insulating member may include an outer groove formed on an outer surface to couple the cap up lower plate, and an inner groove formed on an inner surface to couple the cap up upper plate.

In this way, the embodiment of the present invention by coupling the cap-up lower plate and the cap-up upper plate respectively on the outside and the inside of the insulating member, so that the coupling force between the cap-up lower plate, the insulating member and the cap-up upper plate is further improved.

The insulating member may include at least one first opening.

In this manner, the embodiment of the present invention allows the internal gas of the battery to be discharged to the outside immediately after the break of the safety vent after breakage, and also the operating pressure of the battery can be lowered.

The insulating member may include at least one second opening formed in an area corresponding to the fuse element.

In this manner, the embodiment of the present invention can provide a space for the molten material to move during fuse blow of the fuse element, thereby preventing explosion or noise of the insulating member.

The insulating member may be opened at a breakdown pressure of 20 to 25 kgf / cm ² .

In this way, embodiments of the present invention can implement a higher operating pressure than the operating pressure of the existing battery (14 to 18 kgf / cm ² ).

The fuse device may be cut at a current of 100 to 300A.

In this way, the embodiment of the present invention makes it easy to select and apply a fuse device that is already sold according to the capacity of the battery and the characteristics of the battery. For example, in the related art, the fuse area had to be newly designed separately according to the battery capacity and the characteristics of the battery, but the embodiment of the present invention can avoid such a trouble.

Various embodiments of the present invention provide a secondary battery capable of blocking the current path by inverting the safety vent when the internal pressure is higher than the reference pressure, and by fusing the fuse when the charge / discharge current is higher than the reference current. . In one embodiment, the embodiment of the present invention responds to the internal pressure of the battery and the current of the battery, respectively, to block the current path to improve the safety and reliability of the battery.

In addition, various embodiments of the present invention provide a secondary battery that can increase the operating pressure of the safety vent and also improve the high temperature neglect storage characteristics. For example, an embodiment of the present invention includes a fuse element, and by manufacturing the cap assembly by the insert injection method, it is possible to increase the operating pressure according to the internal pressure of the battery, so that even if left for a long time at high temperature characteristics of the battery ( As the internal pressure of the battery increases, the shape of the opening of the safety vents is accelerated.

1A to 1C are perspective, cross-sectional and exploded perspective views illustrating a cylindrical lithium ion secondary battery according to various embodiments of the present disclosure.
2A to 2D are top, bottom, perspective and cross-sectional views illustrating a cap up of a cap assembly in a cylindrical lithium ion secondary battery according to various embodiments of the present disclosure.
3A and 3B are top perspective views and cross-sectional views illustrating a cap assembly in a cylindrical lithium ion secondary battery according to various embodiments of the present disclosure.
4 is a cross-sectional view illustrating a cap up of a cap assembly in a cylindrical lithium ion secondary battery according to various embodiments of the present disclosure.
5 is a cross-sectional view illustrating a cap up of a cap assembly in a cylindrical lithium ion secondary battery according to various embodiments of the present disclosure.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, and the following examples can be modified in various other forms, and the scope of the present invention is It is not limited to an Example. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the inventive concept to those skilled in the art.

In addition, in the following drawings, the thickness or size of each layer is exaggerated for convenience and clarity of description, the same reference numerals in the drawings refer to the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items. In addition, the term "connected" in this specification means not only the case where the A member and the B member are directly connected, but also the case where the A member and the B member are indirectly connected by interposing the C member between the A member and the B member. do.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. Also, as used herein, "comprise, include" and / or "comprising, including" means that the features, numbers, steps, actions, members, elements, and / or groups thereof mentioned. It is intended to specify the existence and not to exclude the presence or addition of one or more other shapes, numbers, operations, members, elements and / or groups.

Although the terms first, second, etc. are used herein to describe various members, parts, regions, layers, and / or parts, these members, parts, regions, layers, and / or parts are defined by these terms. It is obvious that not. These terms are only used to distinguish one member, part, region, layer or portion from another region, layer or portion. Accordingly, the first member, part, region, layer or portion, which will be described below, may refer to the second member, component, region, layer or portion without departing from the teachings of the present invention.

Terms relating to spaces such as "beneath", "below", "lower", "above", and "upper" are associated with one element or feature shown in the figures. It can be used for easy understanding of other elements or features. Terms related to this space are for easy understanding of the present invention according to various process conditions or use conditions of the present invention, and are not intended to limit the present invention. For example, if an element or feature in the figures is inverted, the element or feature described as "bottom" or "bottom" will be "top" or "top". Thus, "bottom" is a concept encompassing "top" or "bottom".

1A to 1C, a perspective view, a cross-sectional view, and an exploded perspective view of a cylindrical lithium ion secondary battery according to various embodiments of the present disclosure are shown.

1A to 1C, the cylindrical lithium ion secondary battery 100 according to various embodiments of the present invention may include a cylindrical can 110, an electrode assembly 120, and a cap assembly 140. Can be. In addition, the cylindrical lithium ion secondary battery 100 may further include a center pin 130 coupled to the electrode assembly 120.

The cylindrical can 110 includes a circular bottom portion 111 and a side portion 112 extending in a predetermined length from the circumference of the bottom portion 111 upward. The upper portion of the cylindrical can 110 is open during the manufacturing process of the secondary battery. Therefore, the electrode assembly 120 and the center pin 130 may be inserted into the cylindrical can 110 together with the electrolyte during the assembly process of the secondary battery. Cylindrical can 110 may include, but is not limited to, steel, nickel plated steel, stainless steel, aluminum, or an aluminum alloy. In addition, the cylindrical can 110 is formed with a beading part 113 recessed therein at a lower portion of the cylindrical cap 110 so as to prevent the cap assembly 140 from escaping to the outside. A crimping part 114 bent inwardly may be formed.

The electrode assembly 120 is received inside the cylindrical can 110. The electrode assembly 120 may include a negative electrode plate 121 coated with a negative electrode active material (eg, graphite, carbon, etc.), a positive electrode plate coated with a positive electrode active material (eg, transition metal oxides (LiCoO 2, LiNiO 2, LiMn 2 O 4, etc.)) 122) and a separator 123 positioned between the negative electrode plate 121 and the positive electrode plate 122 to prevent shorting and to allow only movement of lithium ions. The negative electrode plate 121, the positive electrode plate 122, and the separator 123 are wound in a substantially cylindrical shape. Here, the negative electrode plate 121 may be a copper (Cu) foil, the positive electrode plate 122 may be an aluminum (Al) foil, and the separator 123 may be polyethylene (PE) or polypropylene (PP). It is not limited. In addition, although the negative electrode tab 124 protruding a predetermined length downwardly may be welded to the negative electrode plate 121, the positive electrode tab 125 protruding a predetermined length upwardly may be welded to the positive electrode plate 122, and vice versa. In addition, the negative electrode tab 124 may be made of nickel (Ni), and the positive electrode tab 125 may be made of aluminum (Al), but the present invention is not limited thereto.

In addition, the negative electrode tab 124 of the electrode assembly 120 may be welded to the bottom 111 of the cylindrical can 110. Therefore, the cylindrical can 110 may operate as a cathode. Of course, the positive electrode tab 125 may be welded to the bottom 111 of the cylindrical can 110, in which case the cylindrical can 110 may operate as a positive electrode.

In addition, a lower insulating plate 126 coupled to the cylindrical can 110 and having a first hole 126a at the center and a second hole 126b at the outside thereof is disposed between the electrode assembly 120 and the bottom 111. May be intervened in The lower insulating plate 126 serves to prevent the electrode assembly 120 from electrically contacting the bottom 111 of the cylindrical can 110. In particular, the lower insulating plate 126 serves to prevent the positive electrode plate 122 of the electrode assembly 120 from being in electrical contact with the bottom 111. Here, when a large amount of gas is generated due to the abnormality of the secondary battery, the first hole 126a serves to quickly move the gas upward through the center pin 130, and the second hole 126b is a negative electrode. The tab 124 serves to penetrate and weld to the bottom 111.

In addition, an upper insulating plate 127 coupled to the cylindrical can 110 and having a first hole 127a at the center and a plurality of second holes 127b at the outside thereof is provided with the electrode assembly 120 and the cap assembly 140. It can be interposed in between. The upper insulating plate 127 serves to prevent the electrode assembly 120 from electrically contacting the cap assembly 140. In particular, the upper insulating plate 127 serves to prevent the negative electrode plate 121 of the electrode assembly 120 from electrically contacting the cap assembly 140. Here, when a large amount of gas is generated due to an abnormality of the secondary battery, the first hole 127a serves to quickly move the gas to the cap assembly 140, and the second hole 127b is the positive electrode tab 125. ) Can be penetrated and welded to the cap assembly 140. In addition, the remaining second holes 127b serve to rapidly flow into the electrode assembly 120 in the electrolyte injection process.

In addition, the diameters of the first holes 126a and 127a of the first and second insulating plates 126 and 127 are smaller than the diameters of the center pins 130, so that the center pins 130 are formed in the cylindrical can 110 by external impact. Do not electrically contact the bottom 111 or the cap assembly 140.

The center pin 130 is in the form of a hollow circular pipe, and may be coupled to approximately the center of the electrode assembly 120. The center pin 130 may be formed of steel, stainless steel, aluminum, aluminum alloy or polybutylene terepthalate, but the material is not limited thereto. The center pin 130 serves to suppress deformation of the electrode assembly 120 during charge and discharge of the battery, and serves as a movement passage of gas generated inside the secondary battery.

The cap assembly 140 is installed under the cap-up 1410, the cap-up 1410, and at the bottom of the safety vent 142 and the safety vent 142 that surround the side and top surfaces of the cap-up 1410. Cap-down 144 and cap-down installed in the lower portion of the insulating ring 143, the safety vent 142 and the insulating ring 143, the first and second through holes 144a and 144b are formed. The subplate 145 and the cap-up 1410, the safety vent 142, the insulating plate 143, the cap-down 144, and the cylindrical can 110, which are fixed to the bottom surface of the 144 and electrically connected to the positive electrode tab 125. It may include an insulating gasket 146 to insulate the side 111 of the ().

Here, the insulating gasket 146 is substantially compressed between the beading portion 113 and the crimping portion 114 formed on the side portion 111 of the cylindrical can 110. In addition, the through-holes 144a and 144b formed in the capdown 144 serve to discharge the internal gas to the outside when abnormal internal pressure occurs in the cylindrical can 110. Of course, by the internal pressure, the safety vent 142 is first inverted upwardly while being electrically separated from the subplate 145, and then the safety vent 142 is torn and gas inside is discharged to the outside.

In addition, an electrolyte solution (not shown) is injected into the cylindrical can 110, and lithium ions generated by electrochemical reactions in the negative electrode plate 121 and the positive electrode plate 122 inside the battery during charge and discharge may be injected. It serves to make it mobile. The electrolyte may be a non-aqueous organic electrolyte that is a mixture of lithium salts and high purity organic solvents. In addition, the electrolyte may be a polymer using a polymer electrolyte, and the type of the electrolyte is not limited thereto.

2A to 2D, a top perspective view, a bottom perspective view, a cross-sectional view, and an exploded perspective view of a cap up 1410 of a cap assembly 140 among cylindrical lithium ion secondary batteries according to various embodiments of the present disclosure are illustrated.

As shown in FIGS. 2A to 2D, the cap up 1410 of the cap assembly 140 of the secondary battery 100 according to various embodiments of the present disclosure may have a cap up lower plate 1420 electrically connected to the electrode assembly 120. The cap-up upper plate 1430 installed on the upper portion of the cap-up lower plate 1420, the fuse element 1440 electrically connecting the cap-up lower plate 1420 and the cap-up upper plate 1430, and the cap-up while wrapping the fuse element 1440. It may include an insulating member 1450 for coupling the lower plate 1420 and the cap-up upper plate 1430.

The cap up lower plate 1420 has an opening 1420a in the center and may be formed in a substantially circular disk shape. In one example, the cap-up lower plate 1420 has an approximately flat lower surface 1421, an approximately flat upper surface 1422 opposite to the lower surface 1421, and an opening 1420a inside between the lower surface 1421 and the upper surface 1422. ) And an outer surface 1424 defining an outer edge between the lower surface 1421 and the upper surface 1422 as an opposite surface of the inner surface 1423.

Here, the opening 1420a may be an area where the safety vent 1460 is inverted when the battery internal pressure is greater than the reference pressure. In addition, the cap-up lower plate 1420 may include, for example, but not limited to, a conductor such as steel plate cold deep drawn extra (SPCE) or an aluminum alloy.

Cap-up top plate 1430 may be formed in the shape of a circular disk. For example, the cap-up top plate 1430 defines an outer edge between an approximately flat bottom surface 1431, an approximately flat top surface 1432 that is the opposite surface of the bottom surface 1431, and a bottom surface 1431 and the top surface 1432. It may include an outer side 1434.

Here, the outer diameter of the outer surface 1434 of the cap-up upper plate 1430 may be smaller than the inner diameter of the inner surface 1423 of the cap-up lower plate 1420. Therefore, the insulating member 1450 formed between the cap up lower plate 1420 and the cap up upper plate 1430 may be naturally formed in an inverted funnel. In addition, the cap-up top plate 1430 may include, for example, but not limited to, a conductor such as steel plate cold deep drawn extra (SPCE) or an aluminum alloy.

The fuse element 1440 may include a fuse 1441, a lower lead 1442 connecting the lower side of the fuse 1441 and the cap-up lower plate 1420, and an upper portion connecting the upper side of the fuse 1441 and the cap-up upper plate 1430. It may include a lead (1443).

Here, the lower lead 1442 may be welded or soldered to the lower surface 1421 of the cap-up lower plate 1420 by laser or ultrasonic wave. In addition, the upper lead 1443 may be welded or soldered to the lower surface 1431 of the cap-up upper plate 1430 by laser or ultrasonic wave.

In this way, the fuse element 1440 electrically connects the cap-up lower plate 1420 and the cap-up upper plate 1430, and becomes a charge / discharge current path between the cap-up lower plate 1420 and the cap-up upper plate 1430.

As an example, the short circuit current of the fuse device 1440 may be determined according to battery characteristics. For example, the short circuit current of the fuse device 1440 may be determined to be approximately 100A to 300A, and the fuse device 1440 may be melted and blown at this current.

The fuse 1442 may include, for example, but not limited to, a lead-tin alloy, a zinc-tin alloy, a copper alloy, an aluminum alloy, or the like. In addition, the fuse element 1440 may include, but is not limited to, a real fuse, an annular fuse, a tubular fuse, and the like.

The insulating member 1450 surrounds the fuse element 1440 and combines the cap up lower plate 1420 and the cap up upper plate 1430. The insulating member 1450 may be formed in the form of an inverted funnel having a lower region coupled to the cap up lower plate 1420 and an upper region coupled to the cap up upper plate 1430.

For example, the insulating member 1450 may have an approximately flat lower surface 1451 formed at a position lower than the lower surface 1421 of the cap up lower plate 1420, and an upper surface 1432 of the cap up upper plate 1430 as an opposite surface of the lower surface 1451. And an upper inclined surface 1452 having approximately the same surface as the one, an outer inclined surface 1453 extending inclined downwardly from the upper surface 1452, and an inclined inner surface 1454 inclinedly extending as an opposite surface of the outer inclined surface 1453. have.

In addition, the insulating member 1450 may be formed between the outer groove 1453a formed in the outer inclined surface 1453 so that the cap up lower plate 1420 is coupled with the upper surface 1452 and the inner inclined surface 1454 so that the cap up upper plate 1430 is coupled thereto. It may include an inner groove (1454a) formed in.

For example, the circumference of the inner surface 1423 and the lower surface 1421 of the cap-up lower plate 1420 is coupled through the outer groove 1453a of the insulating member 1450, and the inner groove 1454a of the insulating member 1450 is coupled. Through the outer periphery 1434 and the lower surface 1431 of the cap-up top plate 1430 may be coupled.

The insulating member 1450 is, for example, but not limited to, polyvinyl chloride resin, polystyrene resin, acrylic resin, nylon resin, thermoplastics such as polypropylene resin, polyester resin, phenol resin, melamine resin, silicone It may be formed of a thermosetting plastic such as resin, urea resin, amino resin, epoxy resin.

Meanwhile, the cap up lower plate 1420, the cap up upper plate 1430, the fuse element 1440, and the insulating member 1450 may be simultaneously formed by an insert injection method. For example, after the fuse element 1440 is electrically connected between the cap-up lower plate 1420 and the cap-up upper plate 1430, and these components are seated inside the mold, the molten insulating resin is injected into the mold, An integrated cap up 1410 with a fuse element 1440 can be manufactured.

In this manner, cap up 1410 can be broken at a pressure of, for example, but not limited to, approximately 20-25 kgf / cm ² . For example, when the internal pressure of the battery reaches approximately 20 to 25 kgf / cm ² , the cap-up top plate 1430 and / or the insulating member 1450 of the cap-up 1410 break and release the internal gas of the battery to the outside. can do.

In this manner, the cap assembly 140 according to the embodiment of the present invention may operate in response to the internal pressure and / or the charge / discharge current of the battery.

For example, when the charge and discharge current of the battery is approximately 100 to 300A, the fuse device 1440 may operate to block the charge and discharge current. As another example, when the internal pressure of the battery is approximately 20 to 25 kgf / cm ² , the insulating member 1450 of the cap up 1410 may be broken to release the internal gas of the battery to the outside.

Therefore, the present invention can not only adjust the short circuit characteristic of the secondary battery 100, but also increase the operating pressure, thereby improving the high temperature storage characteristic.

3A and 3B, a top perspective view and a cross-sectional view of a cap assembly 140 in a cylindrical lithium ion secondary battery 100 according to various embodiments of the present disclosure are shown.

As shown in FIGS. 3A and 3B, the safety assembly 1460 is coupled to the cap assembly 140 under the cap-up lower plate 1420 of the cap-up 1410 of the secondary battery 100 according to various embodiments of the present disclosure. Can be.

In one example, the safety vent 1460 extends outwardly from the bent portion 1460a and the first extension portion which extends outward from the bent portion 1460a to contact the lower surface 1451 of the insulating member 1450. The second portion 1462 and the second extension portion 1462 and the second extension portion which are bent upward from the first extension portion 1451 and extend outward to contact the lower surface 1421 of the cap-up lower plate 1420. The first extension part 1463 is bent upwardly from 1462 and contacts the outer surface 1424 of the cap up lower plate 1420, and the third extension part 1463 is bent horizontally from the third extension part 1463 to form the lower cap 1420. The fourth extension part 1464 may contact the upper surface 1422.

On the other hand, the insulating ring 143 is coupled to the second extension portion 1462 of the safety vent 1460 in the form of a ring, and the cap down 144 is coupled to the lower portion of the safety vent 1460 and the insulation ring 143. Can be. Due to the insulation ring 143, a predetermined space or gap is formed between the safety vent 1460 and the cap down 144.

In addition, the cap down 144 may include a first through hole 144a formed at the center thereof, and the bent portion 1460a of the safety vent 1460 may be extended to the inside of the first through hole 144a. . In addition, the cap down 144 may further include a plurality of second through-holes 144b for discharging gas. In addition, a subplate 145 covering the first through hole 144a is coupled to a lower surface of the cap down 144. The sub plate 145 may be electrically connected to the positive electrode tab 125 of the electrode assembly 120.

In this way, when the internal pressure of the battery is greater than the preset reference pressure, for example, when the internal pressure of the battery is greater than approximately 20 to 25 kgf / cm ² , the gas inside the battery is used for gas discharge provided with the capdown 144. The safety vent 1460 is pushed upward through the second through hole 144b. Therefore, the bent portion 1460a of the safety vent 1460 is inverted, and the electrical connection state between the bent portion 1460a of the safety vent 1460 and the subplate 145 is released. In one example, the current path between the safety vent 1460 and the sub plate 145 is blocked.

On the other hand, when the battery current is greater than the preset reference current, for example, when the battery current is greater than approximately 100 to 300A, the fuse 1421 of the fuse element 1440 is blown. Accordingly, the electrical connection state between the cap up lower plate 1420 and the cap up upper plate 1430 of the cap up 1410 is released. In one example, the current path between the cap-up lower plate 1420 and the cap-up upper plate 1430 of the cap-up 1410 is blocked.

In this way, in the secondary battery 100 according to the embodiment of the present invention, since the cap assembly 140 incorporates the fuse element 1440, safety and reliability are improved. In one example, the cap assembly 140 according to an embodiment of the present invention to block the current by the internal pressure and / or current of the battery to improve the safety and reliability of the battery.

For example, the cap assembly 140 of the secondary battery 100 according to the embodiment of the present invention, when the internal pressure of the battery is higher than approximately 25 to 25 kgf / cm ² , the safety vent 1460 is inverted safety vent Block the current path between the 1460 and the sub-plate 145. Here, since the safety vent 1460 and the subplate 145 are welded to each other, the safety vent 1460 and the subplate 145 are separated from each other according to the welding quality or the welding position. Can be large.

In addition, the cap assembly 140 of the secondary battery 100 according to the embodiment of the present invention, when the current of the battery is approximately 100 to 300A, the fuse element 1440 is blown while the cap-up lower plate 1420 of the cap assembly 140 ) And the current path between the cap-up top plate 1430. Here, the melting point of the fuse device 1440 may be determined relatively accurately according to the amount of current. In one example, the fuse element 1440 is designed to melt at a current of approximately 100 A, the fuse element 1440 is designed to melt at a current of approximately 200 A, or the fuse element 1440 is designed to melt at a current of approximately 300 A. Can be.

In addition, in the secondary battery 100 according to the embodiment of the present invention, the operation of the fuse device 1440 and the operation of the safety vent 1460 are independently performed, thereby further improving safety and reliability of the secondary battery 100. have.

For example, when the internal pressure of the secondary battery 100 is not higher than the reference pressure and only a large current flows in the secondary battery 100, the fuse element 1440 operates (for example, the fuse element 1440 is operated). By melting), the current path can be interrupted.

For example, when no overcurrent flows in the secondary battery 100 and only the internal pressure of the secondary battery 100 is higher than the reference pressure, the safety vent 1460 operates (for example, the safety vent 1460). ) Is reversed so that the safety vent 1460 and the sub-plate 145 are electrically separated), so that the current path may be blocked.

Of course, even after the blocking of the current path, if the internal pressure of the secondary battery 100 is further increased, the insulating member 1450 or the cap-up top plate 1430 of the cap up 1410 of the cap assembly 140 may be 110. By separating from the, the internal gas of the secondary battery 100 may be released to the outside.

Referring to FIG. 4, a cross-sectional view of a cap up 2410 of a cap assembly 140 among cylindrical lithium ion secondary batteries according to various embodiments of the present disclosure is shown.

As shown in FIG. 4, the cap up 2410 of the cap assembly 140 of the secondary battery 100 according to various embodiments of the present disclosure further includes at least one opening 2411 formed in the insulating member 1450. can do. The opening 2411 may be formed to completely pass through the outer inclined surface 1453 and the inner inclined surface 1454 of the insulating member 1450, and the internal gas of the secondary battery 100 may be discharged to the outside through the opening 2411. Can be. In addition, due to the opening 2411 of the insulating member 1450, the internal pressure of the secondary battery 100 may be determined only by the safety vent 1460. For example, when the safety vent 1460 is inverted and ruptured by the internal pressure, the internal gas may be immediately discharged to the outside through the opening 2411 formed in the insulating member 1450 of the cap up 2410.

As such, the secondary battery according to various embodiments of the present disclosure may have a safe operation when the secondary battery has a relatively low internal pressure, for example, greater than about 14 to 18 kgf / cm ² .

Referring to FIG. 5, a cross-sectional view of a cap up 3410 of a cap assembly 140 in a cylindrical lithium ion secondary battery 100 according to various embodiments of the present disclosure is shown.

As shown in FIG. 5, the cap up 3410 of the cap assembly 140 of the secondary battery 100 according to various embodiments of the present disclosure further includes at least one fuse hole 3411 formed in the insulating member 1450. It may include. The fuse hole 3411 may be formed in a region of the fuse element 1440 corresponding to the fuse 1441. For example, the fuse hole 3411 may be formed between the fuse 1441 and the outer inclined surface 1453 of the insulating member 1450. For example, the molten material of the molten fuse 1441 may be discharged to the outside of the battery through the fuse hole 3411. Therefore, the insulation member 1440 does not explode or generate noise during the operation of the fuse device 1440.

What has been described above is just one embodiment for implementing the cylindrical lithium ion secondary battery according to the present invention, the present invention is not limited to the above embodiment, as claimed in the following claims of the present invention Without departing from the gist of the present invention, one of ordinary skill in the art will have the technical spirit of the present invention to the extent that various modifications can be made.

100; Cylindrical lithium ion secondary battery according to the present invention
110; Can 111: bottom
112; Side 113; Beading part
114; Crimping unit 120; Electrode assembly
121; Negative plate 122; Positive plate
123; Separator 124; Negative electrode tab
125; Positive electrode tab 126; Lower insulation board
126a; First hole 126b; 2nd Hall
127; Upper insulating plate 127a; Hall 1
127b; Second hole 130; Center pin
140; Cap assembly
1410; Cap up 1420; Cap-Up Bottom
1420a; Opening 1421; if
1422; Upper surface 1423; Medial side
1424; Outer surface 1430; Cap-up tops
1431; 1432; Top
1434; Outer side 1440; Fuse elements
1441; Fuse 1442; Lower lead
1443; Upper lid 1450; Insulation member
1451; 1452; Top
1453; Outer slope 1453a; Outer groove
1454; Inner inclined surface 1454a; Inner groove
1460; Safety vent 1460a; Bend
1461; First extension 1462; Second extension
1463; Third extension 1464; 4th Extension
143; Insulation ring 144; Capdown
144a; First through hole 144b; 2nd through hole
145; Subplate 146; Insulation Gasket

Claims (9)

Cylindrical cans;
An electrode assembly housed in the cylindrical can; And
A cap assembly for sealing the cylindrical can,
The cap assembly may include a cap up bottom plate electrically connected to the electrode assembly, a cap up top plate installed on an upper portion of the cap up bottom plate, a fuse element electrically connecting the cap up bottom plate and the cap up top plate, and encapsulate the cap element while surrounding the fuse element. A secondary battery comprising an insulating member for coupling the lower plate and the cap-up upper plate. The method of claim 1,
The cap-up lower plate is formed in a circular disk shape having an opening in the center, and the cap-up upper plate is formed in a circular disk shape. The method of claim 1,
The fuse device includes a fuse, a lower lead connecting one side of the fuse and the cap-up lower plate, and an upper lead connecting the other side of the fuse and the cap-up upper plate. The method of claim 1,
The insulating member has a lower end coupled to the cap-up lower plate, and a secondary battery formed in an inverted funnel shape coupled to the cap-up upper plate. The method of claim 1,
The insulating member includes an outer groove formed on an outer surface to couple the cap up lower plate, and an inner groove formed on an inner surface to couple the cap up top plate. The method of claim 1,
The insulating member includes at least one first opening. The method of claim 1,
The insulating member includes at least one second opening formed in a region corresponding to the fuse element. The method of claim 1,
The insulating member is a secondary battery opened at a breakdown pressure of 20 to 25 kgf / cm ² . The method of claim 1,
The fuse device is a secondary battery is cut at a current of 100 to 300A.

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