Cap assembly, secondary battery including the same, and battery pack

Abstract

The present invention relates to a secondary battery, which includes: an electrode assembly; a can configured to accommodate the electrode assembly; an electrolyte, which is distributed throughout the electrode assembly when injected into the can; and a cover assembly installed on the opening of the can, wherein the cover assembly includes: a top cover, in which a top hole is formed to pass vertically; a safety vent, which is arranged below the top cover and in which a vent hole is formed to pass vertically; and a current interrupter filter, which is arranged below the safety vent, to which a positive electrode tab arranged in the electrode assembly is coupled, and in which a current interrupter hole is formed to pass vertically, wherein the current interrupter hole is closed or opened by the positive electrode tab.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2020-0014554, filed on February 6, 2020, which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present invention relates to a cap assembly, a secondary battery and a battery pack including the same, and more particularly, to a cap assembly from which gas is easily discharged, a secondary battery and a battery pack including the same. Background Art

[0004] Generally, a secondary battery refers to a rechargeable and dischargeable battery, unlike a non-rechargeable primary battery. Secondary batteries are widely used in high-tech electronic fields such as mobile phones, notebook computers, and video cameras.

[0005] Secondary batteries are classified into can type secondary batteries and pouch type secondary batteries, and the can type secondary batteries include an electrode assembly, an electrolyte, a can accommodating the electrode assembly and the electrolyte, and a cap assembly mounted on an opening of the can.

[0006] However, since the cap type secondary battery has a structure in which the inside of the can is sealed therein, gas generated inside the can during an activation process is not discharged to the outside, so there is a limitation in improving battery performance. Summary of the invention

[0007] Technical issues

[0008] The present invention is invented to solve the above problems, and an object of the present invention is to provide a cap assembly that discharges gas generated in a can to the outside after an activation process to improve battery performance, a secondary battery and a battery pack including the cap assembly.

[0009] Technical Solution

[0010] A secondary battery according to the present invention for achieving the above-mentioned purpose includes: an electrode assembly; a can configured to accommodate the electrode assembly; an electrolyte that spreads throughout the electrode assembly when injected into the can; and a cover assembly mounted on the opening of the can, wherein the cover assembly includes: a top cover in which a top hole is formed that passes vertically therethrough; a safety vent that is disposed below the top cover and in which a vent hole that passes vertically therethrough is formed; and a current interrupt device filter that is disposed below the safety vent, to which a positive electrode tab disposed in the electrode assembly is coupled, and in which a current interrupt device hole that passes vertically therethrough is formed, wherein the current interrupt device hole is closed or opened by the positive electrode tab.

[0011] Since the top hole, the vent hole and the current interrupter hole are formed on the same vertical line, the positive electrode tab closing the current interrupter hole can be seen from the outside through the top hole, the vent hole and the current interrupter hole.

[0012] The diameter of the vent hole may be larger than the diameter of each of the top hole and the current interrupt device hole.

[0013] The safety vent and the current interrupt device filter may be coupled to each other to connect the vent hole to the current interrupt device hole.

[0014] A gap between an outer peripheral surface of the vent hole and an outer peripheral surface of the current interrupt device hole connected to each other may be sealed.

[0015] The positive electrode tab may include a lower tab portion and an upper tab portion, wherein the lower tab portion may be connected to the electrode assembly, and the upper tab portion may have one end connected to the lower tab portion and coupled to the current interrupt device filter, and the other end surface-contacting with the bottom surface of the current interrupt device filter to close the current interrupt device hole or separating from the bottom surface of the current interrupt device filter to open the current interrupt device hole, in which the current interrupt device hole is formed.

[0016] The positive electrode tab may be made of a material having elastic restoring force so that the other end of the upper tab portion elastically surface-contacts with the bottom surface of the current interruption device filter 143 .

[0017] A lower end of an inner circumferential surface of the current interrupt device hole and the positive electrode tab may be coupled to be sealed.

[0018] The positive electrode tab may include a sealing protrusion inserted into the current interrupt device hole to seal the current interrupt device hole.

[0019] The sealing protrusion may be formed as a hemispherical protrusion.

[0020] A sealing ball may be inserted into the current interrupt device hole.

[0021] The secondary battery may further include a closing cover coupled to the top hole, wherein the closing cover may be made of the same material as the top cover.

[0022] A battery pack according to the present invention includes: a secondary battery; and a battery case configured to accommodate one or more secondary batteries.

[0023] The cap assembly according to the present invention includes: a top cover in which a top hole is formed to pass vertically; a safety vent which is arranged below the top cover and in which a vent hole is formed to pass vertically; and a current interrupter filter which is arranged below the safety vent and in which a current interrupter hole is formed to pass vertically.

[0024] The top hole, the vent hole and the current interruption device hole may be formed on the same vertical line.

[0025] Beneficial effects

[0026] The secondary battery according to the present invention may include a cover assembly provided with a top cover, a safety vent and a current interrupt device filter. Here, a top hole may be formed in the top cover, a vent may be formed in the safety vent, and a current interrupt device hole may be formed in the current interrupt device filter. The current interrupt device hole may be closed by contacting the surface of a positive electrode tab coupled to the current interrupt device filter. Due to this feature, the positive electrode tab of the current interrupt device hole of the current interrupt device filter may be pressed to close by the top hole, the vent and the current interrupt device hole. Therefore, the current interrupt device hole may be opened to discharge the gas generated in the tank to the outside through the current interrupt device hole, the vent and the top hole, thereby significantly improving the battery performance by discharging the gas generated in the tank.

[0027] In addition, in the secondary battery according to the present invention, the top hole, the vent hole and the current interrupt device hole can be formed on the same vertical line. Due to this feature, the positive electrode tab closing the current interrupt device hole can be seen from the outside through the top hole, the vent hole and the current interrupt device hole, and thus the positive electrode can be easily pressed to open the current interrupt device hole.

[0028] The top hole, the vent hole and the current interruption device hole may partially overlap each other on the same vertical line. That is, when viewed from the top of the cover assembly, the top hole, the vent hole and the current interruption device hole may only partially overlap each other to prevent unnecessary foreign matter from being introduced.

[0029] In addition, in the secondary battery according to the present invention, the diameter of the vent hole can be greater than the diameter of each of the top hole and the current interruption device hole. Due to this feature, the tool passing through the top hole can pass through the vent hole more effectively, and in particular prevent the vent hole from being damaged by the tool.

[0030] In addition, in the secondary battery according to the present invention, the safety vent and the current interruption device filter can be coupled to each other to connect the vent hole to the current interruption device hole. Due to this feature, the tool passing through the top hole can be more effectively inserted into the vent hole and the current interruption device hole.

[0031] In addition, in the secondary battery according to the present invention, the positive electrode tab can be made of a material having elastic restoring force. Due to this feature, the positive electrode tab can be in surface contact with the bottom surface of the current interrupt device filter. Therefore, the current interrupt device hole can be stably closed to prevent the current interrupt device hole from being accidentally opened.

[0032] In addition, in the secondary battery according to the present invention, a hemispherical sealing protrusion can be formed on the positive electrode tab, which seals the current interrupter hole when inserted into the current interrupter hole. Due to this feature, the current interrupter hole can be closed more stably.

[0033] In addition, in the secondary battery according to the present invention, the sealing ball can be inserted into the interconnected current interruption device hole. Due to this feature, when the gas generated in the tank is completely discharged, the vent hole and the current interruption device hole can be sealed to prevent the electrolyte in the tank from being discharged to the outside, thereby improving safety.

[0034] In addition, in the secondary battery according to the present invention, the closing cover can be coupled to the top hole of the top cover. Due to this feature, the coupling between the external terminal and the top cover can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a cross-sectional view of a secondary battery according to a first embodiment of the present invention.

[0036] Figure 2 yes Figure 1 A partial enlarged view of .

[0037] Figure 3 is a diagram showing a state in which a positive electrode tab is pressed in a secondary battery according to a first embodiment of the present invention.

[0038] Figure 4 is a cross-sectional view of a sealing protrusion formed on a positive electrode tab of a secondary battery according to a first embodiment of the present invention.

[0039] Figure 5 is a cross-sectional view showing a sealing ball of a secondary battery according to a first embodiment of the present invention.

[0040] Figure 6 is a cross-sectional view showing a closing cover of a secondary battery according to a first embodiment of the present invention.

[0041] Figure 7 is a flowchart showing a method for manufacturing a secondary battery according to a first embodiment of the present invention.

[0042] Figure 8 is a cross-sectional view showing a cap assembly manufacturing step of the method for manufacturing a secondary battery according to the first embodiment of the present invention.

[0043] Fig. 9 is a cross-sectional view illustrating an electrode assembly and an electrolyte containing step of a method for manufacturing a secondary battery according to a first embodiment of the present invention.

[0044] Fig.10 is a cross-sectional view showing a preliminary battery manufacturing step of the method for manufacturing a secondary battery according to the first embodiment of the present invention.

[0045] Fig.11 is a cross-sectional view showing an activation step of the method for manufacturing a secondary battery according to the first embodiment of the present invention.

[0046] Fig.12 is a cross-sectional view showing a gas exhaust step of the method for manufacturing a secondary battery according to the first embodiment of the present invention.

[0047] Fig.13 is a cross-sectional view showing a welding step of the method for manufacturing a secondary battery according to the first embodiment of the present invention.

[0048] Fig.14 is a cross-sectional view showing a sealing ball inserting step of the method for manufacturing a secondary battery according to the first embodiment of the present invention.

[0049] Fig.15 is a cross-sectional view showing a joining step of the method for manufacturing a secondary battery according to the first embodiment of the present invention.

[0050] Fig.16 is a cross-sectional view showing a closed step of the method for manufacturing a secondary battery according to the first embodiment of the present invention.

[0051] Fig.17 is a diagram of a battery pack according to a second embodiment of the present invention.

[0052] Fig.18 is a sectional view of a cap assembly according to a third embodiment of the present invention. DETAILED DESCRIPTION

[0053] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings in such a manner that a person of ordinary skill in the art to which the present invention belongs can easily perform the technical ideas of the present invention. However, the present invention can be implemented in different forms and should not be construed as being limited to the embodiments described herein. In the accompanying drawings, any content that is not necessary for describing the present invention will be omitted for clarity, and the same reference numerals in the accompanying drawings represent the same elements.

[0054] [Secondary battery according to first embodiment of the present invention]

[0055] like Figures 1 to 6 As shown, the secondary battery 100 according to the first embodiment of the present invention includes an electrode assembly 110 , an electrolyte 120 , a can 130 accommodating the electrode assembly 110 and the electrolyte 120 , and a cap assembly 140 mounted on an opening of the can 130 .

[0056] The electrode assembly 110 has a structure in which a positive electrode tab is provided. That is, the electrode assembly 110 has a structure in which a plurality of electrodes and a plurality of separators are alternately stacked and wound into a roll shape. In addition, the plurality of electrodes include a positive electrode and a negative electrode. In addition, the positive electrode is provided with a positive electrode tab 111 coupled to the cap assembly 140, and the negative electrode is provided with a negative electrode tab coupled to the bottom surface of the can 130.

[0057] The electrolyte 120 is configured to improve the performance of the electrode assembly and spreads throughout the electrode assembly when injected into the can 130 .

[0058] The can 130 includes a receiving portion having an upper portion having an open cylindrical shape, a lower portion receiving therein the electrode assembly 110 and the electrolyte 120, and a sealing portion having an upper portion on which the cap assembly 140 is mounted.

[0059] The cap assembly 140 is mounted on the opening of the can. In particular, the cap assembly 140 may have a structure in which a gas generated in the can 130 in a process of activating the secondary battery is discharged to the outside.

[0060] That is, the cover assembly 140 includes: a top cover 141, which is formed with a top hole 141a that vertically passes through the top cover 141; a safety vent 142, which is arranged below the top cover 141 and has a vent 142a that vertically passes through it; and a current interrupt device filter 143, which is arranged below the safety vent 142, and the positive electrode tab 111 set in the electrode assembly 110 is coupled to the current interrupt device filter 143, and has a current interrupt device hole 143a that vertically passes through the current interrupt device filter 143, wherein the current interrupt device hole 143a is closed or opened by the positive electrode tab 111.

[0061] Here, when the positive electrode tab 111 contacts the surface of the current interrupter filter 143 including the current interrupter hole 143a, the current interrupter hole 143a is closed, and when the positive electrode tab 111 is spaced apart from the current interrupter filter 143 including the current interrupter hole 143a, the current interrupter hole 143a is opened.

[0062] Reference Figure 3In the cap assembly 140 having the above structure, the tool 1 having a long rod shape may pass through the top hole 141a of the top cover 141, the vent hole 142a of the safety vent 142, and the current interruption device hole 143a of the current interruption device filter 143, and then, the positive electrode tab 111 that closes the current interruption device hole 143a may be pressed. Therefore, when the current interruption device hole 143a is opened, the gas generated in the can 130 may be discharged to the outside through the current interruption device hole 143a, the vent hole 142a, and the top hole 141a to significantly improve the performance of the secondary battery.

[0063] That is, in the secondary battery 100 according to the first embodiment of the present invention, since the current interrupt device hole 143a is closed by the positive electrode tab 111 during the activation process, charging and discharging can be stably performed. After the activation process, the gas generated in the tank during the activation process can be discharged to the outside through the cap assembly 140. After the gas is discharged, the positive electrode tab 111 and the current interrupt device hole 143a can be welded to be sealed, thereby preventing leakage of the electrolyte.

[0064] Therefore, the secondary battery 100 according to the first embodiment of the present invention may include the cap assembly 140 having the gas discharge structure. In the cap type secondary battery having the above features, the gas generated in the can after the activation process may also be discharged to the outside to significantly improve battery performance.

[0065] Here, each of the top hole 141a, the vent hole 142a, and the current interruption device hole 143a has a minimum diameter into which the tool 1 can be inserted. For example, the diameter of each of the top hole 141a, the vent hole 142a, and the current interruption device hole 143a may be 1 mm to 3 mm to discharge the gas inside the tank to the outside and also prevent foreign matter from being introduced into the top hole 141a, the vent hole 142a, and the current interruption device hole 143a.

[0066] Here, the top hole 141a, the vent hole 142a and the current interruption device hole 143a may be formed on the same vertical line. Figure 1, the top hole 141a of the top cover 141, the vent hole 142a of the safety vent 142, and the current interruption device hole 143a of the current interruption device filter 143 are arranged in the vertical direction and are also arranged on the same vertical line. Therefore, the positive electrode tab 111 that closes the current interruption device hole 143a can be seen from the outside through the top hole 141a, the vent hole 142a, and the current interruption device hole 143a. As a result, it is easy to confirm from the outside of the secondary battery whether the current interruption device hole 143a is closed. In particular, since the top hole 141a, the vent hole 142a, and the current interruption device hole 143a are arranged on a straight line, the positive electrode tab 111 can be pressed more effectively to open the current interruption device hole 143a. Here, the top hole 141a is formed at the center point of the top cover, the vent hole 142a is formed at the center point of the safety vent, and the current interruption device hole 143a is formed at the center point of the current interruption device filter 143 to minimize the weakening of strength.

[0067] The top hole 141a, the vent hole 142a, and the current interruption device hole 143a may be partially arranged on the same vertical line. For example, only half of the top hole 141a, the vent hole 142a, and the current interruption device hole 143a may be arranged on the same vertical line, and the other half may be arranged on different vertical lines. Therefore, it is possible to significantly prevent unnecessary objects from being introduced into the top hole 141a, the vent hole 142a, and the current interruption device hole 143a, and in particular, it is possible to prevent the positive electrode tab from being pressed by unnecessary objects.

[0068] The diameter β of the vent hole 142a may be greater than the diameter α of each of the top hole 141a and the current interruption device hole 143a. That is, when inserting a tool for pressing the positive electrode tab 111, it may be difficult to easily insert the tool into the vent hole 142a provided between the top hole 141a and the current interruption device hole 143a due to the movement phenomenon of the tool. Therefore, the diameter of the vent hole 142a may be greater than the diameter of the top hole 141a and the current interruption device hole 143a, so that the tool passing through the top hole 141a easily passes through the vent hole 142a. In particular, the vent hole 142a can be prevented from being damaged by the tool used to press the positive electrode tab 111. That is, the safety vent 142 may be cut to prevent the secondary battery from exploding, and the defect of the safety vent may occur due to the damage of the vent hole 142a. To prevent this problem, the diameter of the vent hole 142a may be larger than the diameter of each of the top hole 141a and the current interruption device hole 143a to prevent the vent hole 142a from being damaged. For example, the diameter α of each of the top hole 141a and the current interruption device hole 143a is 2 mm, and the diameter of the vent hole 142a is 3 mm.

[0069] The vent hole 142a and the current interrupt device hole 143a may be connected to each other, and the safety vent 142 and the current interrupt device filter 143 may be coupled to each other. Therefore, the vent hole 142a and the current interrupt device hole 143a may be arranged on the same vertical line. In particular, the outer peripheral surface of the vent hole 142a and the outer peripheral surface of the current interrupt device hole 143a may be coupled to be sealed, thereby preventing foreign matter from being introduced into the vent hole 142a and the current interrupt device hole 143a or preventing the electrolyte from leaking from the vent hole 142a and the current interrupt device hole 143a through the gap between the safety vent 142 and the current interrupt device filter 143.

[0070] The positive electrode tab 111 includes a lower tab portion 111a and an upper tab portion 111b. The lower tab portion 111a is connected to the positive electrode of the electrode assembly 110, and the upper tab portion 111b has one end connected to the lower tab portion 111a and coupled to the current interruption device filter 143 and the other end surface-contacting with the bottom surface of the current interruption device filter 143 in which the current interruption device hole 143a is formed to close the current interruption device hole. That is, the upper tab portion 111b surface-contacts with the current interruption device filter 143, one end of the upper tab portion is coupled to the current interruption device filter 143 by welding, and the other end surface-contacting with the current interruption device filter 143 including the current interruption device hole 143a to close the current interruption device hole. Here, when the other end of the upper tab portion 111b closing the current interruption device hole 143a is pressed, the other end of the upper tab portion 111b is separated from the current interruption device hole 143a to open the current interruption device hole 143a. When the force pressing the other end of the upper tab portion is removed, the other end of the upper tab portion 111b again contacts the current interrupter filter surface including the current interrupter hole 143a by the restoring force of the upper tab portion 111b to close the current interrupter hole.

[0071] Therefore, the positive electrode tab 111 can stably close the current interrupter hole until the activation process of the secondary battery, and after the activation process, when the positive electrode tab 111 is spaced apart from the current interrupter filter 143, the current interrupter hole can be opened to easily discharge the gas in the tank to the outside.

[0072] After the gas is exhausted, the inner peripheral surface of the current interrupter hole 143a and the positive electrode tab 111 are coupled to be sealed. That is, after the gas is exhausted, the other end of the upper tab portion 111b in contact with the bottom surface of the current interrupter filter 143 is sealingly coupled to the current interrupter filter 143 to prevent the current interrupter hole from opening again, thereby preventing leakage of the electrolyte.

[0073] The positive electrode tab 111 is made of a material having an elastic restoring force. Therefore, the other end of the upper tab portion 111b elastically contacts the bottom surface of the current interruption device filter 143 to stably close the current interruption device hole 143a. In particular, when the external force pressing the other end of the upper tab portion 111b is removed, the other end of the upper tab portion 111b quickly returns to its original position by the elastic restoring force, and as a result, the current interruption device hole 143a can be quickly and stably closed. Here, the positive electrode tab 111 may be an alloy steel including a material having an elastic restoring force.

[0074] The positive electrode tab 111 includes a sealing protrusion 111b-1 inserted into the current interruption device hole 143a. That is, the sealing protrusion 111b-1 is configured to increase the sealing force between the positive electrode tab 111 and the current interruption device hole 143a. The sealing protrusion 111b-1 has the same diameter as the current interruption device hole 143a. Therefore, the sealing protrusion 111b-1 is inserted into the current interruption device hole 143a to increase the sealing force between the positive electrode tab 111 and the current interruption device hole 143a. In particular, the sealing protrusion 111b-1 is formed as a hemispherical protrusion. Therefore, the sealing protrusion 111b-1 can be easily coupled to the current interruption device hole 143a or can be easily separated from the current interruption device hole 143a.

[0075] When the discharge of the gas generated in the tank is completed, the sealing ball 150 is inserted into the current interruption device hole 143a. The sealing ball 150 is configured to seal the current interruption device hole 143a and has a spherical shape. Here, the sealing ball 150 is inserted into the current interruption device hole 143a through the top hole 141a and the vent hole 142a to seal the current interruption device hole 143a. In particular, the sealing ball 150 is melted by a hot melt device (not shown). Therefore, the sealing ball 150 can contact the inner peripheral surface of the current interruption device hole 143a to increase the sealing force between the current interruption device hole 143a and the sealing ball 150.

[0076] The cover assembly 140 further includes a closing cover 160 coupled to the top hole 141a. That is, the closing cover 160 is configured to increase the connectivity of the connection terminal connected to the top cover 141, and is made of the same material as the top cover 141. Therefore, foreign matter introduced through the top hole 141a can be blocked, and the connectivity of the connection terminal can be improved.

[0077] Hereinafter, a method for manufacturing a secondary battery according to the present invention will be described.

[0078] [Method for manufacturing a secondary battery according to the first embodiment of the present invention]

[0079] like Figures 7 to 16As shown, the method for manufacturing a secondary battery according to the first embodiment of the present invention includes a cover assembly manufacturing step (S10), an electrode assembly and electrolyte containing step (S20), a preliminary battery manufacturing step (S30), an activation step (S40), a gas exhaust step (S50), a welding step (S60), a sealing ball inserting step (S70), a joining step (S80) and a closing step (S90).

[0080] Reference Figure 8 The cover assembly manufacturing step (S10) includes a cover assembly stamping process and a cover assembly assembling process. In the cover assembly stamping process, a top hole 141a is stamped out vertically through the center of the top surface of the top cover 141 using a stamping device (not shown), a vent hole 142a is stamped out vertically through the center of the top surface of the safety vent 142 using a stamping device (not shown), and a current interruption device hole 143a is stamped out vertically through the center of the top surface of the current interruption device filter 143 using a stamping device (not shown).

[0081] Here, when manufacturing the cap assembly, the top hole 141a, the vent hole 142a and the current interruption device hole 143a are punched to be arranged on the same vertical line. This is done to stably insert a tool to pass through the top hole 141a, the vent hole 142a and the current interruption device hole 143a.

[0082] Here, the vent hole 142a is punched to have a diameter greater than that of each of the top hole 141a and the current interruption device hole 143a to prevent the vent hole 142a from being damaged by a tool passing through the top hole 141a. For example, the diameter of the vent hole 142a is 1 mm to 2 mm greater than that of each of the top hole 141a and the current interruption device hole 143a.

[0083] During the assembly of the cap assembly, the top cap 141 having the top hole 141a is disposed on the upper side, the safety vent 142 having the vent hole 142a is disposed below the top cap 141, and the current interruption device filter 143 having the current interruption device hole 143a is disposed below the safety vent 142. Here, the top hole 141a of the top cap 141, the vent hole 142a of the safety vent 142, and the current interruption device hole 143a of the current interruption device filter 143 are disposed on the same vertical line. In addition, a gasket 144 is coupled to surround the outer peripheral surface of the top cap and the safety vent.

[0084] The cover assembly manufacturing step (S10) also includes a safety vent and a current interruption device filter coupling process. In the safety vent and the current interruption device filter coupling process, the engaging device is inserted through the top hole 141a, and the safety vent 142 is in close contact with the top surface of the current interruption device filter 143 to connect the vent hole 142a to the current interruption device hole 143a. In this state, heat is applied to couple the safety vent 142 to the current interruption device filter 143.

[0085] Here, the safety vent 142 and the current interrupter filter 143 are coupled to each other so that the gap between the vent hole 142a and the current interrupter hole 143a is completely sealed. That is, the outer peripheral surfaces of the vent hole and the current interrupter hole corresponding to each other are coupled to be sealed.

[0086] When the cap assembly manufacturing step ( S10 ) is completed, the cap assembly having the top hole, the vent hole, and the current interruption device hole may be manufactured.

[0087] Therefore, when the above-mentioned process is completed, the cap assembly 140 is completed.

[0088] In the electrode assembly and electrolyte containing step (S20), refer to Fig. 9 After the electrode assembly 110 is received through the opening of the can 130, the electrolyte 120 is injected into the can 130. As a result, the electrolyte is spread throughout the electrode assembly 110.

[0089] Here, the electrode assembly 110 has a structure in which a plurality of electrodes and a plurality of separators are alternately stacked and wound into a roll shape. The plurality of electrodes include a positive electrode and a negative electrode. In addition, the positive electrode is provided with a positive electrode tab 111 coupled to the cap assembly 140, and the negative electrode is provided with a negative electrode tab coupled to the bottom surface of the can 130.

[0090] Reference Fig.10 , a preliminary battery manufacturing step (S30) is performed to manufacture a preliminary battery that is not charged and not discharged, and the preliminary battery manufacturing step (S30) includes an arrangement process and a coupling process.

[0091] During the arrangement, the cap assembly 140 is disposed on the can 130. Here, the cap assembly 140 is disposed so that the current interruption device filter 143 of the cap assembly 140 and the positive electrode tab 111 of the electrode assembly 110 are close to each other.

[0092] During the coupling process, the positive tab 111 provided in the electrode assembly 110 is coupled to the current interruption device filter 143 of the cap assembly 140 in a state where the current interruption device hole 143a is closed. The positive tab 111 includes a lower tab portion 111a connected to the electrode assembly 110 and an upper tab portion 111b connected to the lower tab portion 111a.

[0093] That is, during the coupling process, the upper tab portion 111b contacts the bottom surface of the current interrupt device filter 143, and then the other end of the upper tab portion 111b is moved to close the current interrupt device hole 143a. Then, one end of the upper tab portion 111b is welded and coupled to the bottom surface of the current interrupt device filter 143. In other words, the upper tab portion 111b has the other end surface-contacted with the bottom surface of the current interrupt device filter 143 including the current interrupt device hole 143a to close the current interrupt device hole 143a, and one end welded to the current interrupt device filter 143 to couple the current interrupt device filter to the positive tab. In particular, the positive tab 111 has an elastic force in the direction of the current interrupt device hole 143a to stably close the current interrupt device hole 143a.

[0094] The other end of the upper tab portion 111b of the positive tab 111 includes a sealing protrusion 111b-1 formed as a hemispherical protrusion. That is, during the joining process, the sealing protrusion 111b-1 can be inserted into the current interrupter hole 143a to increase the coupling force and sealing force between the positive tab and the current interrupter hole.

[0095] When the coupling of the positive electrode tab and the cap assembly is completed as described above, the cap assembly 140 is coupled to the opening of the can 130. As a result, the preliminary battery 100A is completed.

[0096] In the activation step (S40), refer to Fig.11 , the preliminary battery 100A is charged and discharged to activate the preliminary battery 100A. Here, due to the mutual reaction between the electrode assembly and the electrolyte, gas is generated in the tank, and the gas is accumulated in the tank 130 to increase the pressure.

[0097] In the gas discharge step (S50), refer to Fig.12 , the gas generated in the tank 130 is discharged to the outside through the cap assembly 140 of the preliminary battery 100A. That is, the tool 1 is inserted through the top hole 141a, the vent hole 142a, and the current interruption device hole 143a of the cap assembly 140 to press down the positive electrode tab 111 in close contact with the current interruption device filter 143. As a result, when the current interruption device hole 143a is opened, the gas generated in the tank 130 is discharged to the outside through the current interruption device hole 143a, the vent hole 142a, and the top hole 141a.

[0098] Thereafter, when the tool 1 pressing the positive electrode tab 111 is removed, the positive electrode tab 111 may return to its original position to close the current interruption device hole 143 a again.

[0099] In the welding step (S60), referring to Fig.13, the current interrupter hole is closed so that the electrolyte inside the tank is not discharged to the outside through the current interrupter hole, the vent hole and the top hole of the cap assembly. That is, in the welding step (S60), the welding device is inserted through the top hole 141a, the vent hole 142a and the current interrupter hole 143a of the cap assembly 140 to weld the lower end of the inner peripheral surface of the current interrupter hole 143a to the positive electrode tab 111. Specifically, by performing welding along the inner peripheral surface of the current interrupter hole 143a in close contact with the positive electrode tab 111, the gap between the current interrupter filter 143 and the positive electrode tab 111 is sealed.

[0100] In the sealing ball inserting step (S70), refer to Fig.14 , the sealing ball 150 is press-fitted into the current interrupt device hole 143a through the top hole 141a and the vent hole 142a. As a result, the current interrupt device hole can be effectively sealed.

[0101] In the joining step (S80), referring to Fig.15 , the melting device 2 is inserted through the top hole 141a and the vent hole 142a, and then a portion of the sealing ball 150 is melted to seal the sealing ball 150 and the current interrupting device hole 143a which are in close contact with each other. As a result, the current interrupting device hole can be completely sealed.

[0102] In the closing step (S90), refer to Fig.16 , the closing cover 160 is coupled to the top hole 141a to close the top hole 141a. Here, the closing cover 160 is made of the same material as the top cover 141. When the closing step is completed, the finished secondary battery 100 is completed.

[0103] Therefore, in the method for manufacturing a secondary battery according to the first embodiment of the present invention, a secondary battery from which gas is discharged can be manufactured.

[0104] Hereinafter, in description of another embodiment of the present invention, constituent elements having the same functions as those of the above-described embodiment are denoted by the same reference numerals in the drawings, and thus repeated description will be omitted.

[0105] [Battery Pack According to Second Embodiment of the Invention]

[0106] like Fig.17 As shown, a battery pack 10 according to the second embodiment of the present invention includes a secondary battery 100 and a battery case 200 in which one or more secondary batteries 100 are accommodated.

[0107] Here, the secondary battery 100 may have the same configuration and function as the secondary battery according to the aforementioned first embodiment, and thus repeated description will be omitted.

[0108] Therefore, the battery pack 10 according to the second embodiment of the present invention may include a secondary battery from which the gas inside the tank is exhausted to significantly improve battery performance.

[0109] [Method for manufacturing a battery pack according to a second embodiment of the present invention]

[0110] The method for manufacturing a battery pack according to the second embodiment of the present invention includes the steps of manufacturing a secondary battery 100 and accommodating the secondary battery 100 in a battery case 200 .

[0111] Here, the steps of manufacturing the secondary battery 100 have the same steps as those of the above-described method for manufacturing a secondary battery, and thus repeated description will be omitted.

[0112] Therefore, in the method for manufacturing a battery pack according to the second embodiment of the present invention, the battery pack 10 including the secondary battery from which the gas generated in the activation step is discharged can be manufactured.

[0113] [Cap assembly according to a third embodiment of the present invention]

[0114] like Fig.18 As shown, the cover assembly 140 according to the third embodiment of the present invention includes: a top cover 141, in which a top hole 141a is formed to pass vertically; a safety vent 142, which is arranged below the top cover 141 and in which a vent hole 142a is formed to pass vertically; and a current interrupt device filter 143, which is arranged below the safety vent 142 and in which a current interrupt device hole 143a is formed to pass vertically.

[0115] The top hole 141a, the vent hole 142a, and the current interrupting device hole 143a are formed on the same vertical line O.

[0116] Here, the cap assembly according to the third embodiment of the present invention has the same configuration and function as the above-mentioned cap assembly included in the secondary battery, and thus repeated description will be omitted.

[0117] Therefore, in the cap assembly according to the third embodiment of the present invention, the gas inside the can may be discharged to the outside through the top hole 141 a , the vent hole 142 a , and the current interruption device hole.

[0118] Therefore, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein. Various modifications made within the equivalent meaning of the claims of the present invention and within the claims should be construed as being within the scope of the present invention.

[0119] [Explanation of Reference Numerals]

[0120] 10: Battery Pack

[0121] 100: Secondary battery

[0122] 110: Electrode assembly

[0123] 120: Electrolyte

[0124] 130: Can

[0125] 140: Cover assembly

[0126] 141: Top cover

[0127] 142: Safety vent

[0128] 143: Current interrupt device filter

[0129] 150: Sealing ball

[0130] 160: Closing cover

[0131] 200: Battery box

Claims

1. A secondary battery comprising: Electrode assembly; a can configured to house the electrode assembly; an electrolyte that, when injected into the can, is distributed throughout the electrode assembly; as well as a cover assembly mounted on the opening of the can, Wherein, the cover assembly comprises: a top cover having a top hole formed therein and passing vertically therethrough; a safety vent, the safety vent being disposed below the top cover and having a vent hole formed therein to pass vertically therethrough; and A current interrupt device filter is arranged below the safety vent, the positive electrode tab arranged in the electrode assembly is coupled to the bottom surface of the current interrupt device filter, and a current interrupt device hole passing vertically is formed in the current interrupt device filter, wherein the current interrupt device hole is closed or opened by the positive electrode tab.

2. The secondary battery according to claim 1, wherein The top hole, the vent hole and the current interrupter hole are formed on the same vertical line, and the positive electrode tab closing the current interrupter hole is visible from the outside through the top hole, the vent hole and the current interrupter hole.

3. The secondary battery according to claim 1, wherein The vent hole has a diameter greater than a diameter of each of the top hole and the current interrupt device hole.

4. The secondary battery according to claim 1, wherein The safety vent and the current interrupt device filter are coupled to each other to connect the vent hole to the current interrupt device hole.

5. The secondary battery according to claim 4, wherein A gap between an outer peripheral surface of the vent hole and an outer peripheral surface of the current interrupt device hole connected to each other is sealed.

6. The secondary battery according to claim 1, wherein The positive electrode tab comprises a lower tab portion and an upper tab portion, wherein the lower tab portion is connected to the electrode assembly, and The upper tab portion has one end connected to the lower tab portion and coupled to the current interrupt device filter, and the other end surface-contacting with a bottom surface of the current interrupt device filter in which the current interrupt device hole is formed to close the current interrupt device hole or separating from the bottom surface of the current interrupt device filter to open the current interrupt device hole.

7. The secondary battery according to claim 6, wherein The positive electrode tab is made of a material having elastic restoring force so that the other end of the upper tab portion elastically surface-contacts with a bottom surface of the current interruption device filter.

8. The secondary battery according to claim 6, wherein A lower end of an inner peripheral surface of the current interrupt device hole and the positive electrode tab are coupled to be sealed.

9. The secondary battery according to claim 1, wherein The positive electrode tab includes a sealing protrusion inserted into the current interrupt device hole to seal the current interrupt device hole.

10. The secondary battery according to claim 9, wherein The sealing protrusion is formed as a hemispherical protrusion.

11. The secondary battery according to claim 4, wherein A sealing ball is inserted into the current interrupt device hole.

12. The secondary battery according to claim 1, further comprising a closing cover coupled to the top hole, in, The closure cover is made of the same material as the top cover.

13. A battery pack comprising: The secondary battery according to claim 1; as well as A battery case is configured to accommodate one or more secondary batteries.

14. A cap assembly configured to be mounted on an opening of a can for accommodating an electrode assembly, the cap assembly comprising: a top cover having a top hole formed therein and passing vertically therethrough; A safety vent, the safety vent being arranged below the top cover and having a vent hole formed therein to pass vertically therethrough; as well as A current interrupt device filter is arranged below the safety vent and a current interrupt device hole is formed in the current interrupt device filter so as to pass vertically therethrough, and a positive electrode tab arranged in the electrode assembly is coupled to a bottom surface of the current interrupt device filter, wherein the current interrupt device hole is closed or opened by the positive electrode tab.

15. The cap assembly according to claim 14, wherein: The top hole, the vent hole and the current interruption device hole are formed on the same vertical line.

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