Cylindrical battery and preparation method thereof

Abstract

The invention provides a cylindrical battery and a preparation method thereof, the cylindrical battery comprises a steel shell, the steel shell comprises an inner cavity and a connecting piece, the inner cavity comprises a first opening and a second opening which are opposite to each other, the connecting piece is connected with the steel shell and seals the first opening, and the connecting piece is made of aluminum; a battery roll core, one end of the battery roll core is a positive collector plate, the other end of the battery roll core is a negative collector plate, and the battery roll core is arranged in the inner cavity and is connected with the connecting piece through the negative collector plate; and the cap is connected with the positive collector plate, seals the other end of the inner cavity, and is made of aluminum. According to the cylindrical battery, the cap, connected with the bus assembly, at the positive electrode is made of the aluminum material, so that the welding efficiency between the bus assembly and the cap is improved, meanwhile, the connecting piece made of the aluminum material is arranged at the negative electrode of the battery roll core, and the connecting piece is connected with the bus assembly, so that the welding efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cylindrical batteries, and in particular to a cylindrical battery and a preparation method thereof. Background Art

[0002] In the current field of battery technology, the cap and main body shell of large cylindrical steel shell batteries are generally made of nickel-plated steel, which is known for its superior corrosion resistance and mechanical strength. The thickness of large cylindrical steel shell batteries is carefully controlled to less than 1 mm, aiming to achieve a balance between lightweight and structural strength. Large cylindrical steel shell batteries are used in battery modules, and the key connecting component in the battery module is the busbar assembly. Because the positive and negative electrodes of cylindrical steel shell batteries are both made of nickel-plated steel, the busbar assembly can only use more expensive materials, such as pure nickel strips, copper nickel-plated layers or nickel-plated steel strips, etc. The choice of these materials undoubtedly increases the manufacturing cost.

[0003] At the same time, due to the limitations of positive and negative electrode materials and busbar assembly materials, the welding process of busbar assemblies and positive and negative electrodes needs to use resistance welding technology. Although this technology is mature and widely used, it faces the challenges of low welding efficiency and limited welding contact area in actual production. Low welding efficiency may lead to longer production cycles and affect capacity expansion; and the limitation of welding area will affect the strength and current carrying capacity of the welded joints, thus posing a potential threat to the overall performance and safety of the battery module. Summary of the invention

[0004] The present invention provides a cylindrical battery and a preparation method thereof, wherein the cylindrical battery is used to solve the problems of low welding efficiency and limited welding contact area when welding a busbar assembly with positive and negative electrodes in the prior art.

[0005] The present invention provides a cylindrical battery, comprising: A steel shell, the steel shell comprising an inner cavity and a connecting piece, the inner cavity comprising a first opening and a second opening opposite to each other, the connecting piece being connected to the steel shell and closing the first opening, the connecting piece being made of aluminum; A battery coil core, one end of the battery coil core is a positive electrode current collecting disk, the other end of the battery coil core is a negative electrode current collecting disk, the battery coil core is arranged in the inner cavity and connected to the connecting member through the negative electrode current collecting disk; A cap is connected to the positive electrode current collecting disk and closes the other end of the inner cavity. The material of the cap is aluminum.

[0006] According to a cylindrical battery provided by the present invention, the connecting piece is riveted to the steel shell.

[0007] According to a cylindrical battery provided by the present invention, the connecting member is provided with a liquid injection hole, and the liquid injection hole is connected to the battery coil core in the inner cavity.

[0008] According to a cylindrical battery provided by the present invention, the cylindrical battery further comprises a sealing nail, wherein the sealing nail penetrates the liquid injection hole and seals the liquid injection hole.

[0009] According to a cylindrical battery provided by the present invention, the cylindrical battery further comprises a sealing cover plate, the sealing cover plate is connected to the steel shell, and the sealing cover plate is arranged at one end of the sealing nail away from the inner cavity.

[0010] According to a cylindrical battery provided by the present invention, the cap further includes a current cut-off device and an explosion-proof valve.

[0011] The present invention also provides a method for preparing a cylindrical battery, which is used to prepare the cylindrical battery as described above, and comprises the following steps: Place the battery core into the inner cavity of the steel shell, and abut the negative electrode current collector of the battery core against the connector in the inner cavity; Perform penetration welding from the bottom of the steel shell to weld the connector to the negative electrode collector plate; The cap is welded together with the positive electrode collector of the battery roll core by laser welding, and the positive electrode is sealed by the cap.

[0012] According to a cylindrical battery preparation method provided by the present invention, before placing the battery core into the inner cavity of the steel shell, it also includes: welding a positive electrode collector disk at the positive electrode of the battery core, welding a negative electrode collector disk at the negative electrode of the battery core, and aligning the negative electrode collector disk of the battery core with the connector along the direction in which the battery core enters the inner cavity.

[0013] According to a cylindrical battery preparation method provided by the present invention, after the positive electrode is sealed, the method further comprises: Inject liquid into the battery coil core in the inner cavity through the injection hole of the connector; After the first injection is completed, the negative pressure forming process is used for forming; After the formation is completed, a second injection is performed into the battery coil core in the inner cavity through the injection hole.

[0014] According to a method for preparing a cylindrical battery provided by the present invention, after secondary liquid injection into the battery coil core in the inner cavity is completed through the injection hole of the connector, the method further includes: inserting a sealing nail into the injection hole, welding the sealing cover plate and the connector together by laser welding, and completing the negative electrode sealing.

[0015] The present invention provides a cylindrical battery and a preparation method thereof, in which the cap is made of aluminum material in the cylindrical battery, and the steel shell is designed to be open at both ends, that is, the inner cavity of the steel shell includes a first opening and a second opening, and is sealed at one end of the steel shell by a connector, which is also made of aluminum material. The first opening and the second opening of the steel shell are sealed respectively by the cap and the connector, so that the busbar assembly is connected to the battery roll core in the steel shell through the cap and the connector. Because the cap and the connector are both made of aluminum material, aluminum material can also be used for the busbar assembly. Then, when the busbar assembly is welded to the cap or the connector, laser welding can be used as the welding method, thereby increasing the welding efficiency and the welding area, thereby solving the problems in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces 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 creative work.

[0017] Figure 1 It is an exploded view of the cylindrical battery provided by the present invention.

[0018] Figure 2 It is a front view of the cylindrical battery provided by the present invention.

[0019] Figure 3 yes Figure 2 Cross-sectional view at AA in the middle.

[0020] Figure 4 It is a cross-sectional view of the cylindrical battery provided by the present invention without the battery roll core installed.

[0021] Figure 5 It is a structural schematic diagram of the connecting piece provided by the present invention.

[0022] Reference numerals: 1. steel shell; 11. inner cavity; 12. connecting piece; 121. injection hole; 13. first opening; 14. second opening; 2. Battery coil core; 21. Positive electrode current collecting plate; 22. Negative electrode current collecting plate; 3. Blocked shots; 4. Sealing nails; 5. Seal the cover. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Combine the following Figure 1 A cylindrical battery of the present invention is described, comprising a steel shell 1, a battery core 2 and a cap 3. The steel shell 1 comprises an inner cavity 11 and a connector 12, the inner cavity 11 comprises a first opening 13 and a second opening 14 opposite to each other, the connector 12 is connected to the steel shell 1 and closes the first opening 13, and the material of the connector 12 is aluminum. One end of the battery core 2 is a positive electrode collector disk 21, and the other end of the battery core 2 is a negative electrode collector disk 22. The battery core 2 is disposed in the inner cavity 11 and connected to the connector 12 through the negative electrode collector disk 22. The cap 3 is connected to the positive electrode collector disk 21, and the cap 3 closes the other end of the inner cavity 11, and the material of the cap 3 is aluminum.

[0025] Please refer to Figures 1 to 4 , this application corresponds to a cylindrical battery, so in this embodiment, the steel shell 1 is in the shape of a circular tube, the steel shell 1 is hollow, and the two ends of the steel shell 1 are open along the axial direction. The hollow part of the steel shell 1 is an inner cavity 11, and the openings at both ends are a first opening 13 and a second opening 14, respectively. The inner cavity 11 is used to store the battery roll core 2, so the diameter of the inner cavity 11 corresponds to the diameter of the battery roll core 2, so that the battery roll core 2 can just be placed in the inner cavity 11. After the cylindrical battery roll core 2 is placed in the inner cavity 11, it is necessary to ensure the stability of the battery roll core 2 to prevent the battery roll core 2 from slipping out of the inner cavity 11. Therefore, in this embodiment, the two ends of the steel shell 1 are sealed by the connector 12 and the cap 3, respectively.

[0026] like Figure 3 As shown, in this embodiment, the connector 12 is connected to the steel shell 1 and seals the first opening 13 of the steel shell 1. After the connector 12 is connected to the steel shell 1, a receiving portion is provided in the inner cavity 11. Then the battery roll core 2 is placed in the inner cavity 11, and the connector 12 is used to provide support for the battery roll core 2 to prevent the battery roll core 2 from sliding out of the inner cavity 11 from the first opening 13. After the battery roll core 2 is placed in the inner cavity 11, the second opening 14 is sealed by the cap 3, so that the two ends of the battery roll core 2 are respectively limited by the connector 12 and the cap 3, so that the battery roll core 2 remains stable in the inner cavity 11.

[0027] Furthermore, if Figure 1As shown, the two ends of the battery core 2 are also provided with a positive current collecting disc 21 and a negative current collecting disc 22, respectively. The positive current collecting disc 21 corresponds to the positive electrode of the battery core 2, the negative current collecting disc 22 corresponds to the negative electrode of the battery core 2, and the positive current collecting disc 21 is provided with an extension handle. Because the cap 3 needs to be connected to the extension handle of the positive current collecting disc 21, when the battery core 2 is placed in the inner cavity 11, the negative current collecting disc 22 of the battery core 2 needs to be aligned with the connector 12, and then the negative current collecting disc 22 and the connector 12 are welded together. Then, after the cap 3 is connected to the extension handle of the positive current collecting disc 21, the second opening 14 is sealed.

[0028] In this embodiment, the connector 12 is connected to the negative current collector 22, and the cap 3 is connected to the positive current collector 21, so the busbar assembly needs to be connected to the positive current collector 21 through the cap 3, and needs to be connected to the negative current collector 22 through the connector 12. The cap 3 and the connector 12 are both made of aluminum material, so the busbar assembly can also be made of aluminum material. Then when the busbar assembly is connected to the cap 3, both are made of aluminum material, which can improve welding efficiency and increase welding area. Similarly, when the busbar assembly is connected to the connector 12, both are made of aluminum material, which can improve welding efficiency and increase welding area.

[0029] Furthermore, in this embodiment, only the cap 3 and the connector 12 are replaced with aluminum materials, while the steel shell 1 itself is not replaced and is still made of steel. Therefore, the cylindrical battery provided by the present invention not only has the good corrosion resistance and high mechanical strength of the steel shell 1, but also improves the welding efficiency and the welding area by replacing the caps 3 and the connector 12 at both ends.

[0030] In one embodiment, the connecting member 12 is riveted to the steel shell 1. Figures 1 to 5 As shown, in this embodiment, the connecting member 12 is disc-shaped, and the outer shape of the connecting member 12 corresponds to the shape of the inner cavity 11, so that the connecting member 12 can fit the inner cavity 11. Because in this embodiment, the connecting member 12 is made of aluminum, the connecting member 12 is manufactured separately from the steel shell 1, and the connecting member 12 and the steel shell 1 are assembled after the manufacturing is completed.

[0031] In this embodiment, the connection method of the connector 12 and the steel shell 1 is riveting. After the connector 12 is placed in the corresponding position of the inner cavity 11, it is connected by mold pressing, thereby ensuring the sealing between the connector 12 and the steel shell 1. An opening of the inner cavity 11 is sealed by the connector 12. In this embodiment, the connector 12 seals the first opening 13 as an example. In different embodiments, it is not limited whether the connector 12 seals the first opening 13 or the second opening 14.

[0032] In one embodiment, the connecting member 12 is provided with a liquid injection hole 121 , and the liquid injection hole 121 is communicated with the battery coil core 2 in the inner cavity 11 .

[0033] like Figures 1 to 5 As shown, a liquid injection hole 121 is provided at the center of the connector 12. The liquid injection hole 121 is a through hole that can connect the spaces on both sides of the connector 12. One side of the connector 12 is connected to the inner cavity 11, and the other side of the connector 12 is connected to the outside. The inner cavity 11 is provided with a battery roll core 2, so the battery roll core 2 is connected to the outside through the liquid injection hole 121.

[0034] When the battery roll core 2 is placed in the inner cavity 11 and the two ends are sealed by the connector 12 and the cap 3, a liquid injection can be performed through the injection hole 121. Then, a negative pressure formation process is adopted to form the cylindrical battery. After the formation is completed, the battery roll core 2 can also be injected with a second liquid through the injection hole 121. The secondary liquid injection can replenish the battery roll core 2, thereby improving the quality of the battery roll core 2.

[0035] In this embodiment, by providing a liquid injection hole 121 on the connecting member 12 , the battery core 2 can be replenished with liquid after formation, thereby improving the quality of the battery core 2 .

[0036] In one embodiment, the cylindrical battery further comprises a sealing nail 4, which is inserted into the injection hole 121 and seals the injection hole 121. In one embodiment, the cylindrical battery further comprises a sealing cover plate 5, which is connected to the steel shell 1 and is arranged at one end of the sealing nail 4 away from the inner cavity 11.

[0037] like Figure 3 As shown, a sealing nail 4 is also provided on the outside of the connector 12, and the diameter of the sealing nail 4 is slightly larger than the diameter of the injection hole 121, so that the sealing nail 4 and the injection hole 121 are interference fit. Preferably, the sealing nail 4 is also elastic. After the secondary injection of the battery core 2 is completed, it is necessary to ensure the sealing of the battery core 2 to prevent the electrolyte in the battery core 2 from leaking. Therefore, after the secondary injection is completed, the sealing nail 4 is inserted into the injection hole 121, and the injection hole 121 is sealed by the sealing nail 4.

[0038] Because the diameter of the sealing nail 4 is slightly larger than the diameter of the injection hole 121, after the sealing nail 4 is inserted into the injection hole 121, the sealing nail 4 with a larger diameter expands outward. During the expansion process, the sealing nail 4 is restricted by the injection hole 121 with a smaller diameter, so that the outer wall surface of the sealing nail 4 abuts against the inner wall surface of the injection hole 121, thereby reducing the gap between the sealing nail 4 and the injection hole 121, thereby achieving a sealing effect.

[0039] Furthermore, because sealing is an important indicator of cylindrical batteries, in order to ensure that the cylindrical batteries have good sealing, a sealing plate 5 is added in this embodiment. When the sealing nail 4 is inserted into the injection hole 121 and the injection hole 121 is sealed, the sealing plate 5 is covered on the sealing nail 4. The sealing plate 5 is connected to the steel shell 1 from the outside, and the sealing plate 5 is arranged on the side of the sealing nail 4 away from the inner cavity 11, and the sealing plate 5 and the steel shell 1 are welded to ensure that the sealing plate 5 can provide good sealing. At the same time, the area of ​​the sealing plate 5 is larger than the area of ​​the sealing nail 4, so that the sealing plate 5 can fully cover the sealing nail 4 during the installation process, thereby sealing the connection between the sealing nail 4 and the injection hole 121.

[0040] Preferably, in this embodiment, the sealing plate 5 is a circular flat plate. The diameter of the sealing plate 5 is larger than the diameter of the sealing nail 4, and the sealing plate 5 is coaxial with the sealing nail 4 during installation, ensuring that the sealing plate 5 can fully cover the sealing nail 4. Furthermore, the diameter of the sealing plate 5 can also be set to correspond to the diameter of the inner cavity 11. Then, when the sealing plate 5 is installed, the sealing plate 5 abuts against the inner wall of the steel shell 1, and then the sealing plate 5 is welded to the inner wall of the steel shell 1. In this way, not only the sealing nail 4 can be sealed, but also the connection between the connecting plate 12 and the steel shell 1 can be protected.

[0041] Then, even if leakage occurs between the connecting plate 12 and the steel shell 1 , the leaked electrolyte flows into the gap between the sealing plate 5 and the connecting plate 12 , and cannot leak from between the sealing plate 5 and the steel shell 1 .

[0042] In one embodiment, the cap 3 further includes a current cut-off device and an explosion-proof valve. Because in the cylindrical battery provided in the present application, a liquid injection hole 121 is opened at the center of the connector 12, and liquid is injected through the liquid injection hole 121 on the connector 12, and there is no need to open a through hole on the cap 3, so the current cut-off device and the explosion-proof valve can be installed on the cap 3.

[0043] Among them, the current cut-off device (CID) can cut off the power in time when the cylindrical battery is damaged or an accident occurs, thereby preventing the cylindrical battery from causing secondary damage due to continued discharge. At the same time, the explosion-proof valve can properly adjust the pressure inside the cylindrical battery and release the pressure when the pressure inside the cylindrical battery is too high, thereby preventing the cylindrical battery from bursting due to excessive internal pressure.

[0044] Furthermore, in the cylindrical battery provided by the present invention, the secondary liquid injection of the battery can be realized by opening the injection hole 121 in the center of the connector 12, and then the safety of the battery can be improved by the current cut-off device (CID) and the explosion-proof valve (vent) designed in the cap 3. In the prior art, because only a through hole can be opened on the cap 3 and then the secondary liquid injection is performed, if you want to perform secondary liquid injection and replenishment after the battery is formed, you can only take the way of opening a through hole on the cap 3. This method will cause the current cut-off device (CID) on the cap 3 to be damaged, or the current cut-off device (CID) cannot be installed on the cap 3. It can be understood that if the current cut-off device (CID) needs to be installed on the cap 3 and the current cut-off device (CID) on the cap 3 is effective, it is not possible to open a hole on the cap 3, so the secondary liquid injection cannot be performed. Therefore, in the prior art, only one of the two secondary liquid injection processes and the current cut-off device (CID) can be retained, thereby reducing the performance of the battery.

[0045] In the present invention, the connecting member 12 is riveted to the steel shell 1, and then a liquid injection hole 121 is provided on the connecting member 12, so that the cylindrical battery provided by the present invention can not only be injected with liquid twice, but also retain components such as a current cut-off device (CID) in the cap 3 to improve safety, thereby greatly improving the overall performance of the cylindrical battery.

[0046] Another embodiment of the present invention further provides a method for preparing a steel shell cylindrical battery, comprising: Place the battery core 2 into the inner cavity 11 of the steel shell 1, and abut the negative electrode current collecting plate 22 of the battery core 2 against the connecting piece 12 in the inner cavity 11; Perform penetration welding from the bottom of the steel shell 1 to weld the connector 12 and the negative electrode current collector 22 together; The cap 3 and the positive electrode current collecting disk 21 of the battery coil core 2 are welded together by laser welding, and the positive electrode is sealed by the cap 3.

[0047] In this embodiment, because the steel shell 1 has been assembled with the connector 12 in advance, and the connection method between the steel shell 1 and the connector 12 is riveting, the battery core 2 can be directly placed in the inner cavity 11 of the steel shell 1, and the battery core 2 is supported by the connector 12. Because the battery core 2 needs to be supported by the connector 12, the connector 12 abuts against the battery core 2, so before the battery core 2 is placed in the inner cavity 11, the negative electrode of the battery core 2 needs to be aligned with the connector 12.

[0048] Because in the present invention, a connector 12 is provided at the bottom of the steel shell 1, and the connector 12 is made of aluminum material, laser penetration welding can be used when welding the connector 12 and the negative electrode current collecting plate 22. The laser penetration welding method can improve the welding efficiency, and the laser penetration welding of aluminum material can also increase the welding area.

[0049] Because the connector 12 has sealed the first opening 13, the battery core 2 needs to be placed into the inner cavity 11 from the second opening 14. During the placement process, the negative electrode of the battery core 2 needs to be aligned with the connector 12 so that the negative electrode of the battery core 2 enters the inner cavity 11 first until the negative electrode of the battery core 2 abuts against the connector 12. At this time, only the second opening 14 is not sealed, and the battery core 2 may slip out of the inner cavity 11 from the second opening 14, or the electrolyte may leak from the second opening 14.

[0050] Therefore, after welding the connector 12 to the negative electrode of the battery core, align the cap 3 with the positive electrode of the battery core. First weld the cap 3 to the positive electrode of the battery core 2, and then close the second opening 14 with the cap 3. The cap 3 is made of aluminum, so laser penetration welding can be used when welding the connector 12 to the positive electrode of the battery core 2. Laser penetration welding can improve welding efficiency, and laser penetration welding of aluminum materials can also increase the welding area. At this point, the assembly of the cylindrical battery is completed.

[0051] In the process provided by the present invention, the connecting piece 12 and the cap 3 are replaced with aluminum materials, thereby improving the welding efficiency and the welding area.

[0052] In one embodiment, before placing the battery core 2 into the inner cavity 11 of the steel shell 1, it also includes: welding the positive electrode collector disk 21 at the positive electrode of the battery core 2, welding the negative electrode collector disk 22 at the negative electrode of the battery core 2, and along the direction in which the battery core 2 enters the inner cavity 11, the negative electrode collector disk 22 of the battery core 2 is removed.

[0053] Because the positive and negative electrodes of the battery core 2 need to be collected and connected to the rest of the parts, in order to facilitate the connection and current collection of the battery core 2, before the battery core 2 is placed in the inner cavity 11, the positive current collector disk 21 will be welded to the positive electrode of the battery core 2, and the negative current collector disk 22 will be welded to the negative electrode of the battery core 2. Furthermore, in order to facilitate the connection of the cap 3, an extension handle is also provided on the positive current collector disk 21. Therefore, after the battery core 2 is placed in the inner cavity 11, it is welded to the connector 12 through the negative current collector disk 22, and welded to the cap 3 through the positive current collector disk 21. In addition, after the cap 3 is welded to the extension handle of the positive current collector disk 21, the extension handle is bent to drive the cap 3 to move to the position of sealing the second opening 14.

[0054] In one embodiment, after the positive electrode is sealed, the method further comprises: Inject liquid into the battery coil core 2 in the inner cavity 11 through the injection hole 121 of the connecting member 12; After the first injection is completed, the negative pressure forming process is used for forming; After the formation is completed, liquid is injected into the battery coil core 2 in the inner cavity 11 through the injection hole 121 for a second time.

[0055] In the present embodiment, because the connector 12 is provided with a liquid injection hole 121, secondary liquid injection can be performed. First, liquid injection is performed once through the liquid injection hole 121, and no sealing is performed after the liquid injection is completed. When the liquid injection hole 121 is not sealed, the cylindrical battery is formed by a negative pressure formation process. After the formation is completed, because the liquid injection hole 121 is not sealed, a secondary liquid injection can be performed through the liquid injection hole 121 to replenish the electrolyte consumed during the formation process. The cylindrical battery after the secondary liquid injection can have better quality and longer service life.

[0056] In this embodiment, the positive electrode is sealed by the cap 3, and the negative electrode is sealed by the connector 12. Then, by opening a liquid injection hole 121 in the connector 12, secondary liquid injection of the cylindrical battery is achieved to improve the quality of the cylindrical battery.

[0057] In one embodiment, after the battery roll core 2 in the inner cavity 11 is injected with liquid through the injection hole 121 of the connector 12, the process further includes: inserting the sealing nail 4 into the injection hole 121, and welding the sealing cover plate 5 and the connector 12 together by laser welding to complete the negative electrode sealing.

[0058] After the secondary injection is completed, the cylindrical battery can be used normally and needs to enter the next process. However, the injection hole 121 may cause leakage of the cylindrical battery during normal use. Therefore, before the cylindrical battery enters the next process, the injection hole 121 needs to be sealed. In this embodiment, the injection hole 121 is first blocked by inserting the sealing nail 4 into the injection hole 121, and then the sealing cover plate 5 and the connecting piece 12 are welded to strengthen the sealing of the sealing nail 4. In this embodiment, a double sealing method of the sealing cover plate 5 and the sealing nail 4 is adopted to ensure the sealing of the cylindrical battery.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cylindrical battery, characterized in that: include: A steel shell (1), the steel shell (1) comprising an inner cavity (11) and a connecting piece (12), the inner cavity (11) comprising a first opening (13) and a second opening (14) opposite to each other, the connecting piece (12) being connected to the steel shell (1) and closing the first opening (13), and the material of the connecting piece (12) being aluminum; A battery core (2), one end of the battery core (2) being a positive electrode current collecting disk (21), the other end of the battery core (2) being a negative electrode current collecting disk (22), the battery core (2) being arranged in the inner cavity (11) and connected to the connecting member (12) via the negative electrode current collecting disk (22); A cap (3), the cap (3) being connected to the positive electrode current collecting disk (21), and the cap (3) closing the other end of the inner cavity (11), and the material of the cap (3) being aluminum.

2. The cylindrical battery according to claim 1, characterized in that: The connecting piece (12) is riveted to the steel shell (1).

3. The cylindrical battery according to claim 1, characterized in that: The connecting piece (12) is provided with a liquid injection hole (121), and the liquid injection hole (121) is connected to the battery coil core (2) in the inner cavity (11).

4. The cylindrical battery according to claim 3, characterized in that: The cylindrical battery further comprises a sealing nail (4), wherein the sealing nail (4) penetrates the liquid injection hole (121) and seals the liquid injection hole (121).

5. The cylindrical battery according to claim 4, characterized in that: The cylindrical battery further comprises a sealing cover plate (5), the sealing cover plate (5) being connected to the steel shell (1), and the sealing cover plate (5) being arranged at an end of the sealing pin (4) facing away from the inner cavity (11).

6. The cylindrical battery according to claim 5, characterized in that: The cover cap (3) also includes a current cut-off device and an explosion-proof valve.

7. A method for preparing a cylindrical battery, characterized in that: The cylindrical battery preparation method is used to prepare the cylindrical battery according to any one of claims 1 to 6, comprising the following steps: The battery core (2) is placed in the inner cavity (11) of the steel shell (1), and the negative electrode current collecting plate (22) of the battery core (2) is brought into contact with the connecting piece (12) in the inner cavity (11); Performing penetration welding from the bottom of the steel shell (1) to weld the connecting piece (12) and the negative electrode current collecting plate (22) together; The cap (3) and the positive electrode current collecting disk (21) of the battery coil (2) are welded together by laser welding, and the positive electrode is sealed by the cap (3).

8. The method for preparing a cylindrical battery according to claim 7, characterized in that: Before placing the battery core (2) into the inner cavity (11) of the steel shell (1), the method further includes: welding a positive electrode current collector (21) to the positive electrode of the battery core (2), welding a negative electrode current collector (22) to the negative electrode of the battery core (2), and aligning the negative electrode current collector (22) of the battery core (2) with the connector (12) along the direction in which the battery core (2) enters the inner cavity (11).

9. The method for preparing a cylindrical battery according to claim 7, characterized in that: After the positive electrode is sealed, it also includes: Injecting liquid into the battery coil core (2) in the inner cavity (11) through the injection hole (121) of the connecting piece (12); After the first injection is completed, the negative pressure forming process is used for forming; After the formation is completed, a second injection of liquid is performed into the battery coil core (2) in the inner cavity (11) through the injection hole (121).

10. The method for preparing a cylindrical battery according to claim 9, characterized in that: After the secondary liquid injection into the battery coil core (2) in the inner cavity (11) is completed through the liquid injection hole (121) of the connecting piece (12), the method further includes: inserting the sealing nail (4) into the liquid injection hole (121), and welding the sealing cover plate (5) and the connecting piece (12) together by laser welding to complete the negative electrode sealing.

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