Large cylindrical battery with high power and high energy density and assembly process thereof

Abstract

The invention discloses a high-power and high-energy-density large cylindrical battery and an assembly process thereof.The large cylindrical battery comprises a shell and a roll core arranged in the shell, the shell comprises two cylindrical half shells which are coaxially arranged, the opposite ends of the two half shells are in butt joint in an insulated and sealed mode in the circumferential direction, and the roll core is arranged in the shell. An inner cavity communicated and connected along the inner wall is formed; the outer end part of one half shell is an opening which is formed by outwards penetrating along the inner wall and is matched with a cover plate which can be welded in a sealing manner; the outer end part of the other half shell is connected with an end plate which is arranged in a closed manner; the roll core is arranged in the inner cavity, and the tabs at the two ends of the roll core are respectively connected with the end plates and the cover plate in a welding manner. The high-power and high-energy-density large cylindrical battery has the advantages that the structure is simple and reasonable, the effective connection area between the roll core and the shell can be enlarged, and the over-current capability and the heat dissipation capability can be guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to a large cylindrical battery with high power and high energy density and an assembly process thereof. Background Art

[0002] Commercial lithium-ion batteries can be divided into three categories according to the packaging form: square, cylindrical, and soft pack; among them, large cylindrical batteries among cylindrical batteries have been a hot spot in the battery industry in recent years, especially in the fields of electric vehicles and energy storage. The design of this battery has attracted attention for its high energy density, excellent rate performance and good safety performance. Full-ear technology is a key feature of large cylindrical batteries. It significantly reduces the internal resistance of the battery by setting current collectors on the surface of the entire electrode, thereby improving the charging and discharging efficiency of the battery. The full-ear design makes the maximum distance of current transmission become the height of the electrode rather than the length, which is usually only 5%-20% of the electrode length, so the resistance is reduced by 5-20 times compared with the single-ear design. This design not only improves the rate performance of the battery, but also helps to improve the safety of the battery, because the full-ear has no concentrated heating point inside the battery, and the heat is evenly distributed inside, which has thermal management advantages for the entire battery package. High-rate discharge is another significant feature of large cylindrical batteries. High-rate batteries can provide faster charging speeds and higher power output, which is particularly important for application scenarios that require fast charging and discharging. For example, some high-rate batteries are able to support fast charging from 0 to 80% in a short period of time, which is of great significance for improving the charging convenience and practicality of electric vehicles.

[0003] In the prior art, the connection between a large cylindrical full-pole tab (a cut-and-stacked full-pole tab and the like) and the shell is usually through a busbar, which has a single disc shape, such as a busbar structure and a large cylindrical battery with a publication number of CN219959327U; or different forms such as a disc + a conductive handle, such as a cylindrical battery busbar cover assembly with a publication number of CN221126086U. In these structures, the full-pole tab is first welded to the busbar, and then the busbar is welded to the shell (or terminal). The effective connection area of ​​the busbar and the shell is limited, which reduces the overall current flow capacity and heat dissipation capacity of the battery cell, limiting the advantages of the full-pole tab battery. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is: how to provide a large cylindrical battery with high power and high energy density and its assembly process which has a simple and reasonable structure and can increase the effective connection area between the core and the shell, thereby facilitating the guarantee of current flow capacity and heat dissipation capacity.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A large cylindrical battery with high power and high energy density comprises a shell and a winding core arranged in the shell, wherein the shell comprises two coaxially arranged cylindrical half shells, the opposite ends of the two half shells are butt-connected in an insulated and sealed manner along the circumferential direction, and form an inner cavity that is connected through the inner wall; the outer end of one of the half shells is an open opening formed by passing through the inner wall outward, and is equipped with a cover plate that can be sealed and welded; the outer end of the other half shell is connected to a closed end plate; the winding core is arranged in the inner cavity, and the pole ears at both ends are respectively welded to the end plate and the cover plate.

[0006] In the above structure, the two half shells are insulated and connected to form an inner cavity for accommodating the core, so that the two half shells and the end plates and cover plates at both ends form independent positive and negative electrodes, avoiding the simultaneous arrangement of positive and negative electrodes at one end, thereby increasing the effective connection area between the core and the shell. In addition, the end plates and cover plates of the above structure can be directly welded to the pole ears of the core, eliminating the busbar, which is beneficial to reducing resistance and ensuring current flow capacity. At the same time, since the busbar is omitted, the inner cavity can accommodate a larger volume of core, thereby improving the energy density of the battery.

[0007] Furthermore, one of the half shells expands outward toward one end of the other half shell to form a joint portion, and the inner diameter of the joint portion is larger than the outer diameter of the half shell; an insulating ring is insulated between the inner wall of the joint portion and the other half shell.

[0008] Furthermore, the insulating ring includes a ring body, the outer diameter of which matches the outer diameter of the coupling part and is sealingly arranged on the inner wall of the coupling part; the inner diameter of the ring body matches the outer diameter of the other half shell and is sealingly sleeved on the half shell; the end of the ring body facing the coupling part has an inner limit ring protruding inward, and the inner limit ring abuts against the end of the other half shell.

[0009] In this way, the inner wall of the joint is insulated from the outer wall of the half shell by the ring body, and at the same time, the end of the half shell is insulated from the inner end of the joint by the inner limiting ring, thereby ensuring reliable insulation between the two half shells.

[0010] Furthermore, one end of the ring body facing the outside of the coupling portion has an outer limiting ring protruding outward, and the outer limiting ring abuts against the end of the coupling portion.

[0011] Furthermore, the insulating ring is formed between the two half shells by injection molding or heat sealing.

[0012] Furthermore, the end plate is a bottom plate integrally formed on the half shell or a cover plate seal-welded on the half shell.

[0013] Furthermore, the edge of the cover plate has a circular edge area, and the middle part of the cover plate is overall sunken relative to the edge area to form a welding area. The outer diameter of one end of the welding area facing the inner cavity matches the inner diameter of the half shell, and the outer diameter of the edge area matches the outer diameter of the half shell.

[0014] In this way, the cover plate and the half shell can be better positioned by matching the outer diameter of the welding area with the inner diameter of the half shell, making it easier to weld the edge area and the half shell.

[0015] Furthermore, the end plate or the cover plate has a liquid injection hole which is arranged through, and the liquid injection hole is matched with a sealing nail.

[0016] Furthermore, the middle parts of the end plate and the cover plate are provided with terminals protruding outward; and the terminals of the end plate or the cover plate are provided with C-shaped explosion-proof notches.

[0017] An assembly process of a large cylindrical battery with high power and high energy density as described above is performed by the following steps: S1. Connect the two half shells by injection molding or heat sealing to form a shell, and test the insulation performance and connection strength of the shell; S2, loading the wound core into the shell through the opening of one of the half shells; S3, applying force to the winding core, so that the pole ear of the winding core is closely fitted with the end plate of the other half shell, and welding the end plate to the pole ear of the winding core; S4. Fit the cover plate onto the opening of the half shell, make the cover plate fit tightly with the pole ear of the winding core, and weld the cover plate to the edge of the shell and the cover plate to the pole ear of the winding core respectively.

[0018] In summary, the large cylindrical battery with high power and high energy density of the present invention has the advantages of simple and reasonable structure, which can increase the effective connection area between the core and the shell, and is beneficial to ensuring the current flow capacity and heat dissipation capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the decomposition structure of an embodiment.

[0020] Figure 2 It is a schematic cross-sectional view of the embodiment.

[0021] Figure 3 for Figure 2 Schematic diagram of the enlarged structure within the dotted circle.

[0022] Figure 4 Schematic diagram of the decomposed structure of the other end of the embodiment.

[0023] Figure 5 It is a schematic diagram of the structure of the half shell and the end plate.

[0024] Figure 6 Schematic diagram of the outer structure of the cover.

[0025] Figure 7 Schematic diagram of the inner structure of the cover. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with embodiments.

[0027] When implementing: Figure 1 to Figure 7 As shown, a large cylindrical battery with high power and high energy density includes a shell 1 and a winding core 2 arranged in the shell 1, the shell 1 includes two coaxially arranged cylindrical half shells 11, the opposite ends of the two half shells 11 are connected to each other in an insulated and sealed manner along the circumferential direction, and form an inner cavity that is connected through the inner wall; the outer end of one of the half shells 11 is an open opening formed by passing through the inner wall outward, and is equipped with a cover plate 4 that can be sealed and welded; the outer end of the other half shell 11 is connected to a closed end plate 3; the winding core 2 is arranged in the inner cavity, and the pole ears at both ends are welded to the end plate 3 and the cover plate 4 respectively.

[0028] In this embodiment, Figure 4 and Figure 5 As shown, the end plate 3 is a bottom plate integrally formed on the half shell 1, and the middle parts of the end plate 3 and the cover plate 4 are provided with terminals protruding outward; the terminals of the end plate 3 are provided with C-shaped explosion-proof notches 6. In addition, the end plate 3 is provided with a through-set injection hole 5, and the injection hole 5 is equipped with a sealing nail.

[0029] like Figure 1 and Figure 4 As shown, one end of the half shell 11 is expanded outward toward the other half shell 1 to form a joint portion 13, and the inner diameter of the joint portion 13 is larger than the outer diameter of the half shell 11; an insulating ring 12 is provided between the inner wall of the joint portion 13 and the other half shell 11 to insulate. Figure 3As shown, the insulating ring 12 includes a ring body 121, the outer diameter of which matches the outer diameter of the joint 13 and is sealedly arranged on the inner wall of the joint 13; the inner diameter of the ring body 121 matches the outer diameter of the other half shell 11 and is sealedly sleeved on the half shell 11; the end of the ring body 121 facing the inside of the joint 13 has an inner stop ring 122 formed by protruding inwards, and the inner stop ring 122 abuts against the end of the other half shell 11. The end of the ring body 121 facing the outside of the joint 13 has an outer stop ring 123 formed by protruding outwards, and the outer stop ring 123 abuts against the end of the joint 13. The inner wall of the joint is insulated from the outer wall of the half shell by the ring body, and at the same time, the end of the half shell is insulated from the inner end of the joint by the inner stop ring, so that reliable insulation between the two half shells can be ensured. In this embodiment, the insulating ring 12 is formed between the two half shells 11 by injection molding.

[0030] like Figure 6 and Figure 7 As shown, the edge of the cover plate 4 has a circular edge area, the middle part of the cover plate 4 is integrally sunken relative to the edge area to form a welding area, the outer diameter of one end of the welding area facing the inner cavity matches the inner diameter of the half shell 11, and the outer diameter of the edge area matches the outer diameter of the half shell 11. In this way, the cover plate and the half shell can be better positioned by matching the outer diameter of the welding area with the inner diameter of the half shell, which facilitates welding of the edge area and the half shell.

[0031] The large cylindrical battery of this embodiment connects the two half shells insulated to form an inner cavity for accommodating the core, so that the two half shells and the end plates and cover plates at both ends form independent positive and negative electrodes, avoiding the simultaneous arrangement of positive and negative electrodes at one end, so that the cores at both ends can have a larger welding area, increasing the effective connection area between the core and the shell. In addition, the end plates and cover plates are directly welded to the pole ears of the core, eliminating the busbar, which is beneficial to reduce the resistance between the busbar and the shell and improve the overall current capacity. At the same time, since the busbar is omitted, it can not only reduce the number of parts, reduce material costs, and simplify the assembly process, but also obtain a larger inner cavity space under the same outer dimensions, so that a larger volume of core can be accommodated, the space utilization rate inside the battery is improved, and the volume energy density of the single cell is improved. The explosion-proof notch on the end plate forms a thinning area, which can ensure that when the internal pressure of the battery cell increases, it will first rupture and release pressure from the explosion-proof notch, thereby ensuring the safety of the battery.

[0032] The large cylindrical battery of this embodiment adopts the following assembly steps: 1. Shell assembly: connect the two half shells into a whole by injection molding, and measure the shell insulation and connection strength; 2. Core into shell: put the wound core into the shell through the opening of one of the half shells; 3. End plate welding surface welding: Apply pressure to the winding core to make the pole ear of the winding core fit closely with the welding surface of the end plate, and use the set laser welding parameters to perform penetration welding on the welding surface of the end plate to fully weld the end plate of the shell and the pole ear of the winding core; 4. Cover plate welding: Close the cover plate and the shell to ensure that they fit well, so that the cover plate welding surface fits tightly with the pole ear of the winding core, and use the set laser welding process to weld along the outer edge of the cover plate for one circle to form a good seal between the cover plate and the shell; use the set laser welding parameters to perform penetration welding on the cover plate welding surface to fully weld the cover plate and the pole ear of the winding core; 5. Battery cell injection: inject liquid into the battery through the injection hole, and positive and negative pressure injection methods can be used; 6. Battery sealing: Place the sealing pin at the injection hole and ensure that it fits well with the injection hole. Use the set laser welding parameters to weld along the gap between the sealing pin and the injection hole for one circle to form a good seal between the sealing pin and the shell.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A large cylindrical battery with high power and high energy density, comprising a shell (1) and a winding core (2) arranged in the shell (1), characterized in that: The shell (1) comprises two coaxially arranged cylindrical half shells (11), the opposite ends of the two half shells (11) being butt-jointed in an insulating and sealing manner along the circumferential direction, and forming an inner cavity that is connected through the inner wall; the outer end of one of the half shells (11) is an open opening formed by passing through the inner wall outward, and is equipped with a cover plate (4) that can be sealed and welded; the outer end of the other half shell (11) is connected to a closed end plate (3); the winding core (2) is arranged in the inner cavity, and the pole ears at both ends are respectively welded to the end plate (3) and the cover plate (4).

2. The large cylindrical battery with high power and high energy density as claimed in claim 1, characterized in that: One end of one of the half shells (11) expands outward toward the other half shell (1) to form a joint portion (13); the inner diameter of the joint portion (13) is greater than the outer diameter of the half shell (11); and an insulating ring (12) is provided between the inner wall of the joint portion (13) and the other half shell (11) to insulate.

3. The large cylindrical battery with high power and high energy density as claimed in claim 2, characterized in that: The insulating ring (12) comprises a ring body (121), the outer diameter of the ring body (121) matches the outer diameter of the joint (13), and the ring body (121) is sealingly arranged on the inner wall of the joint (13); the inner diameter of the ring body (121) matches the outer diameter of the other half shell (11), and the ring body (121) is sealingly sleeved on the half shell (11); and the end of the ring body (121) facing the inside of the joint (13) has an inner limit ring (122) protruding inwardly, and the inner limit ring (122) abuts against the end of the other half shell (11).

4. The large cylindrical battery with high power and high energy density as claimed in claim 3, characterized in that: One end of the ring body (121) facing the outside of the connecting portion (13) has an outer limiting ring (123) protruding outwards, and the outer limiting ring (123) abuts against the end of the connecting portion (13).

5. The large cylindrical battery with high power and high energy density as claimed in claim 2, characterized in that: The insulating ring (12) is formed between the two half shells (11) by injection molding or heat sealing.

6. The large cylindrical battery with high power and high energy density as claimed in claim 1, characterized in that: The end plate (3) is a bottom plate integrally formed on the half shell (1) or a cover plate (4) seal-welded on the half shell (1).

7. The large cylindrical battery with high power and high energy density as claimed in claim 6, characterized in that: The edge of the cover plate (4) has a circular ring-shaped edge area, the middle part of the cover plate (4) is integrally sunken relative to the edge area to form a welding area, the outer diameter of one end of the welding area facing the inner cavity matches the inner diameter of the half shell (11), and the outer diameter of the edge area matches the outer diameter of the half shell (11).

8. The large cylindrical battery with high power and high energy density as claimed in claim 1, characterized in that: The end plate (3) or the cover plate (4) is provided with a liquid injection hole (5) which is arranged through-through, and the liquid injection hole (5) is equipped with a sealing nail.

9. The large cylindrical battery with high power and high energy density as claimed in claim 1, characterized in that: The middle parts of the end plate (3) and the cover plate (4) are each provided with a terminal protruding outwards; and the terminal of the end plate (3) or the cover plate (4) is provided with a C-shaped explosion-proof notch.

10. An assembly process for a large cylindrical battery with high power and high energy density as claimed in any one of claims 1 to 9, characterized in that: Use the following steps to assemble: S1. Connect the two half shells by injection molding or heat sealing to form a shell, and test the insulation performance and connection strength of the shell; S2, loading the wound core into the shell through the opening of one of the half shells; S3, applying force to the winding core to make the pole ear of the winding core fit tightly with the end plate of the other half shell, and welding the end plate to the pole ear of the winding core; S4. Fit the cover plate onto the opening of the half shell, make the cover plate fit tightly with the pole ear of the winding core, and weld the cover plate to the edge of the shell and the cover plate to the pole ear of the winding core respectively.

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