A cylindrical lithium-ion battery and a method for manufacturing the same

Abstract

The application relates to the technical field of batteries, and provides a cylindrical lithium ion battery and a preparation method thereof, which comprises a shell, a roll core, a positive electrode current collector, a cover plate assembly and a sealing rivet. The shell has an inner cavity and is provided with a placing opening at one end, and the shell is a conductor. The roll core is arranged in the inner cavity, and the roll core is provided with a positive electrode at the placing opening. A negative electrode is electrically connected with the shell. The positive electrode current collector is electrically connected with the positive electrode of the roll core. The positive electrode current collector is provided with a protrusion on the side away from the roll core. The cover plate assembly comprises an insulating cover plate and a connecting rivet. The cover plate is covered on the placing opening and is electrically connected with the shell. The connecting rivet is arranged on the cover plate, the connecting rivet is provided with a connecting hole, and the protrusion is embedded in the connecting hole. The sealing rivet is embedded in the connecting hole, and the sealing rivet is a core-pulling rivet. The positive electrode and the negative electrode of the battery are led to the same side, the design and manufacturing of a module are facilitated, the traditional metal connecting sheet is cancelled, the overcurrent capacity is greatly enhanced, the internal resistance of the battery is reduced, and the fast charging and discharging of the battery at a large rate is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a cylindrical lithium ion battery and a preparation method thereof. BACKGROUND

[0002] Lithium batteries, as a new generation of green and environmentally friendly batteries, have been widely used in various industries due to their high energy, high working voltage, wide working stability range, small size and other advantages. At the same time, people's requirements for the performance of lithium batteries are also getting higher and higher.

[0003] At present, the positive and negative electrodes of the steel shell cylindrical lithium battery are generally on the opposite sides, so that when the battery module is made, it can only be welded on the opposite sides through the connecting sheet, resulting in a relatively complex module structure. In addition, the current collector plate of the battery needs to be welded with the cover through the metal connecting sheet. Due to the limitation of the size of the metal connecting sheet, the overcurrent capacity of the battery will be affected, resulting in a relatively large internal resistance of the battery, which affects the overcurrent capacity of the battery and is not conducive to the large rate fast charging and fast discharging of the battery.

[0004] How to simplify the battery module structure and improve the overcurrent capacity of the battery to realize the large rate fast charging and fast discharging of the battery has become an important issue to be solved at present. SUMMARY

[0005] The present application provides a cylindrical lithium ion battery and a preparation method thereof to solve the defects of complex battery module structure and large resistance in the prior art, so as to simplify the battery module structure, improve the overcurrent capacity of the battery and realize the large rate fast charging and fast discharging of the battery.

[0006] The present application provides a cylindrical lithium ion battery, comprising: a shell, a roll core, a positive current collector plate, a cover plate assembly and a sealing rivet.

[0007] The shell has an inner cavity and is provided with a placing opening at one end, and the shell is a conductor.

[0008] The roll core is arranged in the inner cavity, and the roll core is formed with a positive electrode at the placing opening and a negative electrode at the other end of the shell; the negative electrode is electrically connected with the shell.

[0009] The positive current collector plate is electrically connected with the positive electrode of the roll core, and the positive current collector plate is electrically insulated from the shell; one side of the positive current collector plate away from the roll core has a protrusion.

[0010] The cover plate assembly comprises an insulating cover plate and a connecting rivet; the cover plate covers the placing opening and is electrically connected with the shell; the connecting rivet is arranged on the cover plate, and a connecting hole is arranged on the connecting rivet; the protrusion is embedded in the connecting hole.

[0011] The sealing rivet is embedded in the connecting hole, and the sealing rivet is a core-pulling rivet.

[0012] According to the cylindrical lithium ion battery provided by the application, the connecting hole comprises a first hole and a second hole arranged coaxially; the second hole is close to the positive current collector and is larger than the first hole; and the shape of the protrusion is matched with the shape of the connecting hole.

[0013] According to the cylindrical lithium ion battery provided by the application, the second hole is a tapered hole and the flared end faces the positive current collector.

[0014] According to the cylindrical lithium ion battery provided by the application, the protrusion is provided with a through hole for connecting the inner cavity.

[0015] According to the cylindrical lithium ion battery provided by the application, the outer shell is provided with a bottom plate at the end away from the placing opening, and the negative current collector is fixed to the bottom plate by laser penetration welding.

[0016] According to the cylindrical lithium ion battery provided by the application, the negative current collector is provided with an annular embedding groove on one side facing the winding core, and a high-temperature-resistant protection ring is embedded in the embedding groove.

[0017] According to the cylindrical lithium ion battery provided by the application, the protection ring is a ceramic ring.

[0018] According to the cylindrical lithium ion battery provided by the application, an insulating ring is sleeved on the periphery of the positive current collector, so that the positive current collector is electrically insulated from the outer shell.

[0019] According to the cylindrical lithium ion battery provided by the application, the cover plate is provided with a communication hole for the connecting rivet to pass through; the cover plate assembly further comprises a first gasket and a second gasket; the first gasket and the second gasket are both sleeved on the connecting rivet, and the cover plate is located between the first gasket and the second gasket; one side of the first gasket facing the cover plate is formed with an annular protruding part, the protruding part passes through the communication hole, the outer wall of the protruding part is fitted with the inner wall of the communication hole, the inner wall of the protruding part is fitted with the connecting rivet, and the end of the protruding part is fitted with the second gasket.

[0020] The application further provides a preparation method of the cylindrical lithium ion battery, comprising:

[0021] laser welding and fixing the winding core positive electrode and the positive current collector;

[0022] embedding the protection ring into the embedding groove, and laser welding and fixing the winding core negative electrode and the negative current collector;

[0023] sleeving the insulating ring on the positive current collector, and then loading the winding core into the outer shell;

[0024] Compress the winding core and perform laser penetration welding on the bottom plate of the shell and the negative electrode collector;

[0025] Install the cover assembly, and insert the protrusion of the positive electrode current collecting disc into the connecting hole;

[0026] Laser welding and sealing of the cover and the shell;

[0027] After the injection is completed, use a sealing nail to seal the connection hole.

[0028] The present invention provides a cylindrical lithium-ion battery and its preparation method. By electrically connecting the negative electrode current collector to the outer shell, the contact area can be increased and the flow capacity can be enhanced. The cover plate can not only serve as a sealing placement port, but also serve as the negative electrode of the battery. The connecting rivet is electrically connected to the positive electrode current collector and can serve as the positive electrode of the battery. As a result, the positive and negative electrodes of the battery are led to the same side, reducing the use of conductive sheets on opposite sides, facilitating the design and production of the module, and reducing the cost of the battery module. In addition, the protrusion on the positive electrode current collector is integrally connected to the connecting rivet and the sealing nail, increasing the contact area between the positive electrode current collector and the connecting rivet and the sealing nail. At the same time, the sealing nail is used to connect the battery cap, eliminating the traditional metal connecting sheet, greatly enhancing the flow capacity, reducing the internal resistance of the battery, and achieving a large rate of fast charging and discharging of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 This is one of the structural diagrams of the cylindrical lithium-ion battery provided by the present invention;

[0031] Figure 2 This is the second structural diagram of the cylindrical lithium-ion battery provided by the present invention;

[0032] Figure 3 yes Figure 2 Enlarged view of part A;

[0033] Figure 4 It is a schematic structural diagram of the negative electrode current collecting disk provided by the present invention;

[0034] Figure 5 yes Figure 2 Enlarged view of part B;

[0035] Figure 6 yes Figure 2 Magnified view of part C.

[0036] Reference signs:

[0037] 1, shell; 10, bottom plate; 100, explosion-proof notch; 2, core; 3, negative current collector; 30, embedding groove; 31, convex ring; 32, support part; 33, welding area; 4, positive current collector; 5, cover plate assembly; 50, cover plate; 51, connecting rivet; 52, connecting hole; 520, first hole; 521, second hole; 522, counterbore; 53, first gasket; 530, protruding part; 54, second gasket; 6, sealing nail; 7, protrusion; 8, protection ring; 9, insulation ring. DETAILED DESCRIPTION

[0038] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0039] In order to facilitate the understanding of the cylindrical lithium ion battery and the preparation method thereof provided by the present application, the application scenarios thereof are first described. The existing large cylindrical lithium battery usually adopts a full-tab structure, that is, an empty foil area is left during tab coating, and the empty foil areas at both ends are flattened and welded with current collectors after the core is formed. In the prior art, the positive and negative electrodes of the battery are located at different sides, so that when the battery module is manufactured, the positive and negative electrodes can only be welded through the conductive sheet at different sides, resulting in a relatively complex module structure. In addition, the positive current collector of the battery needs to be welded with the cap through a metal connecting sheet, which is limited by the size of the metal connecting sheet and affects the overcurrent capacity of the battery, resulting in a relatively large internal resistance of the battery. Therefore, it is not conducive to the fast charging and discharging of the battery at a large rate. Therefore, the present application provides a cylindrical lithium ion battery and a preparation method thereof to simplify the battery module structure, improve the overcurrent capacity of the battery, and realize the fast charging and discharging of the battery at a large rate.

[0040] The cylindrical lithium ion battery and the preparation method thereof provided by the present application will be described below. Figures 1-6

[0041] Referring to Figure 1 A cylindrical lithium ion battery includes a shell 1, a core 2, a negative current collector 3, a positive current collector 4, a cover plate assembly 5, and a sealing nail 6. The shell 1 has an inner cavity, and one end of the shell 1 is provided with a placing opening communicating with the inner cavity for placing the core 2 in the inner cavity. The shell 1 is made of a conductive metal material, for example, stainless steel or nickel-plated carbon steel. The core 2 is arranged in the inner cavity, and the core 2 forms a positive electrode at the placing opening of the shell 1 and a negative electrode at the other end of the shell 1. ​

[0042] The negative current collector 3 is arranged at the negative electrode of the winding core 2 and is electrically connected with the negative electrode of the winding core 2, and the negative current collector 3 is also electrically connected with the shell 1, so as to lead the negative electrode of the winding core 2 to the same side of the positive electrode. The positive current collector 4 is arranged at the positive electrode of the winding core 2, and the positive current collector 4 is electrically connected with the positive electrode of the winding core 2 and is electrically insulated from the shell 1. The positive current collector 4 is provided with a protrusion 7 on the side away from the winding core 2.

[0043] With reference to Figure 2 and Figure 3 The cover plate assembly 5 comprises a cover plate 50 and a connecting rivet 51. The cover plate 50 covers the placement opening and is electrically connected with the shell 1, so as to serve as the negative electrode of the battery. The connecting rivet 51 is arranged on the cover plate 50 and is electrically insulated from the cover plate 50. The connecting rivet 51 is provided with a connecting hole 52, which is fitted with the protrusion 7 on the positive current collector 4, so as to electrically connect the connecting rivet 51 with the positive current collector 4, thereby serving as the positive electrode of the battery. The sealing rivet 6 is fitted with the connecting hole 52 and is used to connect the battery cap. The sealing rivet 6 is made by core-pulling riveting, which can save cost and process compared with traditional welding.

[0044] In actual production, the negative current collector 3 is electrically connected with the shell 1, so as to increase the contact area and enhance the overcurrent capacity. The cover plate 50 can not only seal the placement opening, but also serve as the negative electrode of the battery. The connecting rivet 51 is electrically connected with the positive current collector 4 and can serve as the positive electrode of the battery. Thus, the positive and negative electrodes of the battery are led to the same side, the use of the opposite-side conductive sheet is reduced, the design and production of the module are facilitated, and the cost of the battery module is reduced. In addition, the protrusion 7 on the positive current collector 4 is integrally connected with the connecting rivet 51 and the sealing rivet 6, which increases the contact area of the positive current collector 4 with the connecting rivet 51 and the sealing rivet 6. The sealing rivet 6 is used to connect the cap of the battery, and the traditional metal connecting sheet is cancelled, which greatly enhances the overcurrent capacity and reduces the internal resistance of the battery, thereby realizing the fast charging and discharging of the battery with a large rate.

[0045] The shell 1 has a bottom plate 10 at the end away from the placement opening. The winding core 2 is wound by a positive electrode sheet, a negative electrode sheet and a separator. The separator wraps the negative electrode sheet, and the negative electrode sheet wraps the positive electrode sheet, so as to form the positive and negative electrodes at the two ends of the winding core 2. The winding core 2 is placed into the shell 1 through the placement opening, and the positive electrode of the winding core 2 is located at the placement opening, and the negative electrode of the winding core 2 is located at the other end of the shell 1.

[0046] With reference to Figure 4The negative current collector 3 is made of metal material with good conductivity, for example, copper plated nickel, copper-nickel composite material, etc. The negative current collector 3 is in the shape of a disc, and the side facing the winding core 2 is defined as the first side, and the side away from the winding core 2 is defined as the second side. The first side is provided with an annular embedding groove 30, and the center of the embedding groove 30 coincides with the center of the negative current collector 3.

[0047] Specifically, referring to Figure 5 and Figure 6 , the embedding groove 30 is formed by stamping, so that the embedding groove 30 is formed on the first side, and a convex ring 31 is formed on the second side at the same time. The convex ring 31 is used to fit with the bottom plate 10 of the shell to form a welding position, and the negative current collector 3 can be welded on the bottom plate 10 of the shell 1 by laser penetration welding. The embedding groove 30 is embedded with a high-temperature-resistant protective ring 8, such as a ceramic ring, to avoid burning out the winding core 2 when welding the negative current collector 3. The center of the second side of the negative current collector 3 is provided with a support part 32, which is flush with the surface of the convex ring 31 and is integrally formed on the negative current collector 3. The support part 32 can play a supporting role to improve the stability of welding.

[0048] Referring to Figure 1 and Figure 4 , a plurality of welding areas 33 are formed on the negative current collector 3, which are located inside the embedding groove 30 and are uniformly arranged around the center of the negative current collector 3. The welding areas 33 are used to weld the negative current collector 3 and the exposed foil of the negative electrode of the winding core 2. One end of the welding area 33 close to the center of the negative current collector 3 is in a connected state with the negative current collector 3, and the other positions are in a disconnected state with the negative current collector 3. Specifically, the welding area 33 can be cut along the outer edge line to form a structure in which the welding area 33 is connected inside and disconnected outside the negative current collector 3. Each welding area 33 can deform independently, so that even if a larger vibration occurs during welding, each welding area 33 can be tightly attached to the exposed foil, thereby ensuring the welding quality of each welding area 33 and the winding core 2 and reducing the problem of false welding. The number and shape of the welding areas 33 can be selected according to actual needs. In the embodiment, there are six welding areas 33, which are in the shape of a sector.

[0049] The positive current collector 4 is made of metal material with good conductivity, for example, pure aluminum material, etc. The positive current collector 4 has the same welding area 33 as the negative current collector 3, which is used to weld the positive current collector 4 and the exposed foil of the positive electrode of the winding core 2. The positive current collector 4 is provided with an insulating ring 9 on the periphery, so that the positive current collector 4 is electrically insulated from the shell 1. Specifically, the insulating ring 9 can be injection molded by polypropylene material, and the insulating ring 9 can also be formed by winding a polyimide adhesive tape on the outside of the positive current collector 4.

[0050] Referring to Figure 3The protrusion 7 is integrally formed on the positive current collector 4. A through hole is arranged on the protrusion 7 at an axial position, and is used to communicate with the inner cavity of the shell 1, so that the protrusion 7 can be used as an injection port of electrolyte while leading out current. The cover plate 50 is made of the same material as the shell 1, and the contact position of the cover plate 50 and the shell 1 is welded by laser sealing, so as to fix and electrically connect the cover plate 50 and the shell 1, and the cover plate 50 is used as the negative electrode of the battery.

[0051] In order to electrically insulate the cover plate 50 and the connecting rivet 51, the cover plate assembly 5 further comprises a first gasket 53 and a second gasket 54 made of insulating material. The center of the cover plate 50 is provided with a communication hole for the connecting rivet 51 to pass through. The first gasket 53 and the second gasket 54 are both sleeved on the connecting rivet 51, and the cover plate 50 is located between the first gasket 53 and the second gasket 54. The upper end of the connecting rivet 51 can be insulated from the cover plate 50 by the first gasket 53, and the lower end of the connecting rivet 51 can be insulated from the cover plate 50 by the second gasket 54, so that the upper and lower ends of the connecting rivet 51 are both in an electrically insulated state with the cover plate 50.

[0052] The first gasket 53 is integrally formed with an annular protruding portion 530 at the center of one surface of the cover plate 50. The outer diameter of the protruding portion 530 is matched with the communication hole. The protruding portion 530 passes through the communication hole and the end surface is in contact with the second gasket 54. The connecting rivet 51 is sleeved in the protruding portion 530. At this time, the outer wall of the protruding portion 530 is in contact with the inner wall of the communication hole, and the inner wall of the protruding portion 530 is in contact with the outer wall of the connecting rivet 51. The protruding portion 530 can electrically insulate the connecting rivet 51 and the communication hole. The first gasket 53 and the second gasket 54 can make the connecting rivet 51 and the cover plate 50 as a whole in an insulating state.

[0053] The connecting hole 52 on the connecting rivet 51 comprises a first hole 520 and a second hole 521 arranged coaxially. The second hole 521 is closer to the positive current collector 4 and larger than the first hole 520. The shape of the protrusion 7 is matched with the shape of the connecting hole 52. After the protrusion 7 is embedded in the connecting hole 52, the contact area between the protrusion 7 and the connecting hole 52 can be increased to enhance the current carrying capacity.

[0054] The first hole 520 is a cylindrical straight hole. The second hole 521 can be a cylindrical hole, a tapered hole, a prism hole, etc. as long as the protrusion 7 with a specific shape can be embedded in the connecting hole 52. In this embodiment, the second hole 521 is a tapered hole, and the flared end of the second hole 521 faces the positive current collector 4. Correspondingly, the protrusion 7 comprises a tapered portion and a cylindrical portion. The tapered portion is close to the positive current collector 4 and is matched with the second hole 521. The cylindrical portion is integrally formed on the tapered portion and is matched with the first hole 520. When the protrusion 7 is embedded in the connecting hole 52, the tapered portion is in contact with the inner wall of the second hole 521, and the cylindrical portion is in contact with the inner wall of the first hole 520.

[0055] A counterbore 522 is formed around the connecting hole 52 on the side of the connecting rivet 51 away from the cover plate 50, and the diameter of the counterbore 522 is larger than that of the first hole 520. When the connecting hole 52 is closed by the sealing rivet 6, the end of the sealing rivet 6 is located in the counterbore 522, so as to improve the flatness of the end of the battery.

[0056] Referring to Figure 5 , the bottom plate 10 of the shell 1 is provided with an explosion-proof notch 100 to improve the explosion-proof capability of the battery. The shape and depth of the explosion-proof notch 100 can be selected according to actual requirements.

[0057] The preparation method of the cylindrical lithium ion battery provided by the application will be described below. The preparation method of the cylindrical lithium ion battery described below can be correspondingly referred to the cylindrical lithium ion battery described above.

[0058] A preparation method of a cylindrical lithium ion battery, comprising:

[0059] S1, manufacturing of the roll core 2;

[0060] 1. Manufacturing of the positive electrode sheet; lithium iron phosphate, conductive agent and binder are mixed in a certain proportion to form slurry, the slurry is coated on the positive electrode current collector aluminum foil in a striped manner, and two strips are coated. 7.5mm empty foil area is left on both sides of the aluminum foil, 15mm empty foil area is left in the middle, and after drying, it is rolled up, then rolled and cut, and the positive electrode sheet is completed.

[0061] The positive electrode current collector is a 15μm carbon-coated aluminum foil with a width of 590mm and a coating surface density of 41.5mg / cm 2 , and the thickness is 195μm after rolling, and the positive electrode sheet is cut into 4 strips, each with a width of 147.5mm.

[0062] 2. Manufacturing of the negative electrode sheet; artificial graphite, conductive agent and binder are mixed in a certain proportion to form slurry, the slurry is coated on the negative electrode current collector copper foil in a striped manner, and two strips are coated. 4.5mm empty foil area is left on both sides of the copper foil, and 9mm empty foil area is left in the middle, and after drying, it is rolled up, then rolled and cut, and the negative electrode sheet is completed.

[0063] The negative electrode current collector is an 8μm copper foil with a width of 590mm and a coating surface density of 19.5mg / cm 2 , and the thickness is 125μm after rolling, and the negative electrode sheet is cut into 4 strips, each with a width of 147.5mm.

[0064] 3. Tab cutting; the rolled positive and negative electrodes are tab cut with a width of 5mm.

[0065] 4. Diaphragm making; the diaphragm is a polyethylene film with 3 μm ceramic coating on one side, total thickness of 12 μm, width of 146 mm.

[0066] 5. Winding; the cut positive and negative electrode sheets and diaphragm are wound into a core 2, with the positive and negative hollow foils on the two sides of the core 2, the ceramic surface of the diaphragm facing the negative electrode, the diaphragm wrapping the negative electrode material area, and the negative electrode material area wrapping the positive electrode material area. The winding is accompanied by inward pre-bending of the tabs. The diameter of the core 2 after winding is 45.2 mm.

[0067] 6. The ends of the core 2 after pre-bending of the tabs are flattened, with the size controlled at 149 mm.

[0068] S2, welding the positive current collector disc 4;

[0069] The positive electrode of the core 2 is assembled with the positive current collector disc 4, with the protrusion 7 on the positive current collector disc 4 facing outward to ensure concentricity of the assembly, and the positive current collector disc 4 is in close contact with the tabs, and then the welding area 33 of the positive current collector disc 4 is laser welded.

[0070] S3, welding the negative current collector disc 3;

[0071] The protective ring 8 is installed in the embedding groove 30 of the negative current collector disc 3; the negative electrode of the core 2 is assembled with the negative current collector disc 3, with the support portion 32 on the negative current collector disc 3 facing outward, the protective ring 8 in contact with the negative electrode, and the assembly concentricity ensured, and the negative current collector disc 3 is in close contact with the tabs, and then the welding area 33 of the negative current collector disc 3 is laser welded.

[0072] S4, welding the bottom plate 10 with the negative current collector disc 3;

[0073] The insulating ring 9 is installed on the positive side of the core 2, and then the core 2 is installed in the steel shell; the core 2 is compressed, and the bottom of the steel shell is laser penetration welded. Then helium detection is performed on the laser penetration welded portion.

[0074] S5, connecting the cover plate assembly 5;

[0075] The cover plate 50 is installed, with the protrusion 7 on the positive current collector disc 4 passing through the connecting hole 52 on the rivet of the cover plate 50 and being pressed into the steel shell, and the cover plate 50 is laser seal welded at the contact portion with the steel shell.

[0076] S6, leak detection;

[0077] Helium is injected from the connecting hole 52, and a helium detection device is used to detect the sealing performance of the battery seal laser welding.

[0078] S7, sealing after liquid injection;

[0079] The first liquid injection is performed on the battery through the connecting hole 52 on the cover plate 50, and the injection amount is 10g; the connecting hole 52 is blocked by using a rubber plug, and the battery is subjected to a pre-forming process, and the gas generated by the battery is discharged through the connecting hole 52.

[0080] The second liquid injection is performed on the battery by removing the rubber plug, and the injection amount is 80g; the connecting hole 52 is filled with helium; the sealing nail 6 is pressed into the connecting hole 52 to perform a pull-riveting sealing; and the sealing property of the connecting hole 52 is detected by using a helium detection device.

[0081] S8, subsequent processing;

[0082] The battery is subjected to cleaning, drying, oiling, heat shrinking, code spraying, and other processes such as formation and capacity distribution.

[0083] After the above steps, the capacity of the completed battery can reach 35Ah (lithium iron phosphate system), the internal resistance is less than or equal to 2.5mΩ, and the 4C charge-discharge temperature rise is less than 30℃.

[0084] The innovation of the present application lies in that: by electrically connecting the negative current collector plate 3 with the shell 1, the contact area can be increased, and the overcurrent capacity can be enhanced; the cover plate 50 can not only play a sealing role in the placement opening, but also can serve as the negative electrode of the battery; the connecting rivet 51 is electrically connected with the positive current collector plate 4, and can serve as the positive electrode of the battery; thus, the positive and negative electrodes of the battery are led to the same side, the use of the opposite side conductive sheet is reduced, the design and production of the module are facilitated, and the cost of the battery module is reduced. In addition, the protrusion 7 on the positive current collector plate 4 is integrally connected with the connecting rivet 51 and the sealing nail 6, which increases the contact area of the positive current collector plate 4 with the connecting rivet 51 and the sealing nail 6, and the sealing nail 6 is used to connect the cover cap of the battery, which cancels the traditional metal connecting sheet, greatly enhances the overcurrent capacity, reduces the internal resistance of the battery, and realizes the fast charging and discharging of the battery with a large ratio.

[0085] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A cylindrical lithium-ion battery, characterized by, The application relates to a battery, which comprises a shell (1), a winding core (2), a positive electrode current collector (4), a cover plate assembly (5) and a sealing nail (6). The shell (1) has an inner cavity and is provided with a placing opening at one end; the shell (1) is a conductor. The winding core (2) is arranged in the inner cavity and is provided with a positive electrode at the placing opening and a negative electrode at the other end of the shell (1); the negative electrode is electrically connected with the shell (1). The positive electrode current collector (4) is electrically connected with the positive electrode of the winding core (2) and is electrically insulated from the shell (1); one side of the positive electrode current collector (4) away from the winding core (2) is provided with a protrusion (7). The cover plate assembly (5) comprises an insulating cover plate (50) and a connecting rivet (51); the cover plate (50) covers the placing opening and is electrically connected with the shell (1); the connecting rivet (51) is arranged on the cover plate (50) and is provided with a connecting hole (52); the protrusion (7) is embedded in the connecting hole (52). The sealing nail (6) is embedded in the connecting hole (52) and is a core-pulling rivet. The battery further comprises a negative electrode current collector (3) connected with the negative electrode of the winding core (2); one side of the negative electrode current collector (3) facing the winding core (2) is a first side, and the other side is a second side; the first side is provided with an annular embedding groove (30), and a convex ring (31) is formed on the second side; the convex ring (31) is used for abutting against a bottom plate (10) of a shell; a high-temperature-resistant protection ring (8) is embedded in the embedding groove (30); a support part (32) is arranged at the center of the second side and is flush with the surface of the convex ring (31) to play a supporting role. The connecting hole (52) comprises a first hole (520) and a second hole (521) arranged coaxially; the second hole (521) is close to the positive electrode current collector (4) and is larger than the first hole (520); the shape of the protrusion (7) is matched with the shape of the connecting hole (52).

2. The cylindrical lithium-ion battery of claim 1, wherein, The second hole (521) is a tapered hole and the flared end faces the positive electrode current collector (4).

3. The cylindrical lithium-ion battery of claim 2, wherein, The protrusion (7) is provided with a through hole for communicating the inner cavity.

4. The cylindrical lithium-ion battery of claim 1, wherein, The negative electrode current collector (3) is fixed to the bottom plate (10) through laser penetration welding.

5. The cylindrical lithium-ion battery of claim 1, wherein, The protection ring (8) is a ceramic ring.

6. The cylindrical lithium-ion battery of claim 1, wherein, An insulating ring (9) is arranged on the periphery of the positive electrode current collector (4) to electrically insulate the positive electrode current collector (4) from the shell (1).

7. The cylindrical lithium-ion battery of claim 1, wherein, The positive electrode current collector (4) is electrically insulated from the shell (1).

8. The cylindrical lithium-ion battery according to any one of claims 1 to 7, characterized in that The cover plate (50) is provided with a communication hole for the connecting rivet (51) to pass through; the cover plate assembly (5) further comprises a first gasket (53) and a second gasket (54); the first gasket (53) and the second gasket (54) are both sleeved on the connecting rivet (51), and the cover plate (50) is located between the first gasket (53) and the second gasket (54); a ring-shaped protruding portion (530) is formed on one side of the first gasket (53) facing the cover plate (50), the protruding portion (530) passes through the communication hole, the outer wall of the protruding portion (530) is fitted with the inner wall of the communication hole, the inner wall of the protruding portion (530) is fitted with the connecting rivet (51), and the end portion of the protruding portion (530) is fitted with the second gasket (54).

9. A method of manufacturing a cylindrical lithium-ion battery, characterized by, A method for preparing a cylindrical lithium ion battery as claimed in any one of claims 1-8, the method comprising: Laser welding the positive electrode of the winding core (2) and the positive electrode current collector (4) to fix them; Embedding the protection ring (8) into the embedding groove (30) to laser weld the negative electrode of the winding core (2) and the negative electrode current collector (3) to fix them; Sleeving the insulating ring (9) on the positive electrode current collector (4), and then loading the winding core (2) into the shell (1); Pressing the winding core (2) to laser penetrate the bottom plate (10) of the shell (1) and the negative electrode current collector (3); Loading the cover assembly, and embedding the protrusion (7) of the positive electrode current collector (4) into the connecting hole (52); Laser welding the cover plate (50) and the shell (1) to seal them; After the liquid injection is completed, using the sealing nail (6) to close the connecting hole (52). After the liquid injection is completed, using the sealing nail (6) to close the connecting hole (52).

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