Cylindrical battery cell and preparation method thereof

Abstract

The cylindrical battery cell comprises a shell and an electrode assembly arranged in the shell, a positive electrode lug and a negative electrode lug are located on the same end face of the electrode assembly, a spacing part is formed between the positive electrode lug and the negative electrode lug, the middle of the electrode assembly is provided with a liquid storage hole in the axis direction of the electrode assembly, and the liquid storage hole is communicated with the liquid storage hole. The liquid storage hole is positioned in the spacing part; the insulation part is located between the positive current collecting plate and the negative current collecting plate, the insulation part abuts against the separation part, a communicating hole is formed in the insulation part and communicates with the liquid storage hole, the positive current collecting plate is connected with the positive tab, and the negative current collecting plate is connected with the negative tab. The tabs of the pole pieces are cut in groups in a tab cutting mode, the positive and negative tabs are located on the same side during winding, a spacing area exists between the positive and negative tabs after the electrode assembly is formed, the positive and negative collector plates are located on the same side and are connected with the conductive terminal of the cover plate after being welded, the electron flowing path is greatly shortened, polarization is reduced, and internal resistance is reduced.

Description

Technical Field

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

[0002] As one of the technical routes, large cylindrical batteries are expected to promote the iterative upgrading of lithium battery technology. Compared with square and soft-pack batteries, cylindrical batteries have the advantages of high production yield, good consistency, and high degree of equipment automation. They have obvious advantages in the field of power batteries, and their market share is gradually increasing. They are expected to become the optimal solution for standard battery cells.

[0003] At present, large cylindrical battery cells have positive and negative electrodes on both sides, and the negative electrode is connected to the shell. During charging and discharging, the path through which electrons flow is long, resulting in large internal resistance and polarization of the battery, which is not conducive to the performance of the battery. Summary of the invention

[0004] In order to solve the technical problems existing in the background technology, the present invention provides a cylindrical battery cell and a preparation method thereof.

[0005] A cylindrical battery cell proposed in the present invention comprises a shell and an electrode assembly arranged in the shell, wherein the electrode assembly has a positive electrode tab and a negative electrode tab. Different from the prior art, the positive electrode tab and the negative electrode tab are located on the same end surface of the electrode assembly, a spacer is formed between the positive electrode tab and the negative electrode tab, and a liquid storage hole is provided in the middle of the electrode assembly along its axis, and the liquid storage hole is located in the spacer;

[0006] A current collecting plate assembly is provided on the electrode assembly, and the current collecting plate assembly includes an insulating portion, a positive current collecting plate and a negative current collecting plate, the insulating portion is located between the positive current collecting plate and the negative current collecting plate, the insulating portion is in contact with the separator, and a connecting hole is opened on the insulating portion, the connecting hole is connected with the liquid storage hole, the positive current collecting plate is connected to the positive electrode tab, and the negative current collecting plate is connected to the negative electrode tab.

[0007] The pole pieces' pole ears are cut into groups through a special pole ear cutting method. The positive and negative pole ears are on the same side during winding. After the electrode assembly is formed, there is a spacing area between the positive and negative pole ears. The positive and negative current collecting plates are on the same side and connected to the conductive terminals of the cover plate after welding, which greatly shortens the electron flow path, reduces polarization, and reduces internal resistance.

[0008] As a further optimized solution of the present invention, the bending direction of the positive electrode tab is opposite to the bending direction of the negative electrode tab;

[0009] This prevents the positive electrode tab from contacting the negative electrode tab.

[0010] As a further optimized solution of the present invention, the electrode assembly is formed by winding a separator, a negative electrode sheet, a separator, and a positive electrode sheet stacked in sequence;

[0011] The positive electrode sheet includes a positive electrode current collector and a positive electrode active material coated on the positive electrode current collector, and the coating width is smaller than the width of the positive electrode current collector, and the positive electrode tab is connected to a blank area of ​​the positive electrode current collector that is not coated with the positive electrode active material;

[0012] The negative electrode sheet includes a negative electrode collector and a negative electrode active material coated on the negative electrode collector, and the coating width is smaller than the width of the negative electrode collector. The negative electrode tab is connected to a blank area of ​​the negative electrode collector that is not coated with the negative electrode active material.

[0013] The positive electrode sheet and the negative electrode sheet are baked, rolled, and cut to form electrode sheets with blank space on one side (including positive electrode sheets and negative electrode sheets), and then the electrode ears (the electrode ears here include positive electrode ears and negative electrode ears) are laser cut. When cutting, the electrode ears of a single winding core are grouped, and the number of electrode ears in each group is cut from small to large within the electrode sheet length required for a single electrode assembly, and the interval between each group is from small to large. The shape of a single electrode ear is a parallelogram, and the gap between the electrode ears is 0.1-0.5mm. Cutting in the above manner can ensure that the positive and negative electrode ears of the electrode assembly after winding and flattening are arranged regularly according to the design requirements, and the positive and negative electrode ears (i.e., the positive electrode ear and the negative electrode ear) are on the same side of the electrode assembly, do not touch each other, and have a certain interval.

[0014] As a further optimized solution of the present invention, the coating width of the negative electrode active material is greater than the coating width of the positive electrode active material.

[0015] As a further optimized solution of the present invention, the positive electrode tabs are provided in plurality, and there is a gap between any two adjacent positive electrode tabs; and / or

[0016] There are a plurality of negative electrode tabs, and there is a gap between any two adjacent negative electrode tabs.

[0017] Thereby ensuring the performance of the battery.

[0018] As a further optimized solution of the present invention, the aperture of the connecting hole is larger than the aperture of the liquid storage hole.

[0019] This ensures that the electrolyte can enter the liquid storage hole from the connecting hole, and facilitates the immersion of the electrode assembly by the electrolyte.

[0020] As a further optimized solution of the present invention, the positive electrode current collecting disc is provided with a positive electrode welding hole, and the negative electrode current collecting disc is provided with a negative electrode welding hole.

[0021] The arrangement of the positive electrode welding hole and the negative electrode welding hole facilitates welding of the positive electrode collector plate to the positive electrode tab and welding of the negative electrode collector plate to the negative electrode tab.

[0022] As a further optimized solution of the present invention, a positive electrode column is provided on the positive electrode collector disk, and a negative electrode column is provided on the negative electrode collector disk.

[0023] The positive electrode current collecting column and the negative electrode current collecting column are connected to the conductive terminal to ensure the performance of the battery.

[0024] As a further optimized solution of the present invention, it also includes a cover plate, which is arranged on the current collecting disk, and is provided with a positive conductive terminal connected to the positive current collecting disk, and is provided with a negative conductive terminal connected to the negative current collecting disk, and an injection hole is opened on the cover plate, and positive through holes and negative through holes are provided on both sides of the injection hole, the negative through holes guide the electrolyte to the part directly opposite to the negative current collecting disk, and the positive through holes guide the electrolyte to the part directly opposite to the positive current collecting disk.

[0025] In some embodiments, the positive conductive terminal is connected to the positive electrode post, and the negative conductive terminal is connected to the negative electrode post.

[0026] A cylindrical battery preparation method, used for producing the above battery structure, comprises the following steps:

[0027] S1, laser cutting the cut positive electrode sheet and negative electrode sheet to form positive electrode tabs and negative electrode tabs respectively;

[0028] S2. Wind the cut positive electrode sheet, negative electrode sheet and separator together, with the positive electrode tab and negative electrode tab on the same side during winding to ensure that the positive and negative electrode tabs of the electrode assembly are on the same side of the electrode assembly after winding, flatten the tabs of the electrode assembly after winding, and the tabs after flattening should be on the same horizontal plane, and the tab stacking thickness should be basically consistent. After flattening, there is a spacing area of ​​about 8-10 mm between the positive electrode tab and the negative electrode tab;

[0029] S3, placing the current collecting plate assembly on the electrode lug side of the electrode assembly, placing the middle part of the insulating portion in the spacing area between the positive and negative electrode lugs, placing the positive electrode current collecting plate on the positive electrode lug, and placing the negative electrode current collecting plate on the negative electrode lug, to prevent the current collecting plate assembly from rotating or tilting;

[0030] S4, performing laser welding, during which the welding tool applies a certain pressure to the collector plate assembly to ensure that the collector plate is in close contact with the pole ear, that is, to ensure that the positive collector plate is in close contact with the positive pole ear, and the negative collector plate is in close contact with the negative pole ear;

[0031] S5, inserting the welded electrode assembly into the shell, with the non-ear side facing downwards, entering the shell first until it reaches the bottom of the shell;

[0032] S6. Place the cover plate at the opening of the shell, and apply a certain pressure to the cover plate with the equipment welding tool to ensure that the two are in good contact, perform peripheral welding, and weld the two together to form a battery cell;

[0033] S7. After baking, liquid injection, infiltration and formation, the semi-finished battery cell after welding needs to be sealed and welded, and the sealing pin is welded to the liquid injection hole.

[0034] In the present invention, the proposed cylindrical battery cell and its preparation method produce a winding core by cutting the pole ears in a special shape. The positive and negative pole ears are designed on the same side to reduce the number of welding times and the number of structural parts of the battery cell. The shell is no longer connected to the negative electrode, which can shorten the electron transmission path of the battery cell, reduce the internal resistance of the battery cell, and improve the cycle life and performance of the battery cell.

[0035] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is an overall schematic diagram of the battery cell of the present invention;

[0037] Figure 2 is a schematic diagram of an electrode assembly of the present invention;

[0038] Figure 3 It is a schematic diagram of the structure of the current collecting plate assembly of the present invention;

[0039] Figure 4 It is a schematic diagram of the current collecting plate of the present invention;

[0040] Figure 5 It is a schematic diagram of the insulating gasket of the present invention;

[0041] Figure 6 This is a schematic diagram of the structure of the cover plate assembly of the present invention;

[0042] Figure 7 This is a schematic diagram of the current collecting plate assembly and the cover plate assembly after assembly according to the present invention;

[0043] Figure 8 is a schematic diagram of a conductive terminal of the present invention;

[0044] Fig. 9 It is a schematic diagram of the shell structure of the present invention;

[0045] Fig.10 This is a schematic diagram of the structure of a current collecting disk according to a second embodiment of the present invention;

[0046] Fig.11 This is a schematic diagram of the structure of an insulating gasket according to a second embodiment of the present invention;

[0047] Fig.12 This is a schematic diagram of the structure of an electrode assembly according to a second embodiment of the present invention;

[0048] Fig.13 This is a schematic diagram of the current collecting plate assembly and the cover plate assembly after assembly according to the second embodiment of the present invention;

[0049] 10. Electrode assembly; 11. Positive electrode tab; 12. Liquid storage hole; 13. Negative electrode tab; 14. Spacer; 20. Collector plate assembly; 21. Positive collector plate; 22. Positive electrode column; 23. Positive electrode welding hole; 24. Negative collector plate; 25. Negative electrode column; 26. Negative electrode welding hole; 27. Air avoidance groove; 28. Coating layer; 29. ​​Insulating part; 31. Cover plate; 32. Positive electrode conductive terminal; 33. Negative electrode conductive terminal; 34. Liquid injection hole; 35. Upper recess; 36. Spacer; 37. Lower recess; 40. Shell; 41. Port. DETAILED DESCRIPTION

[0050] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar symbols throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0051] like Figure 1-Figure 9 A cylindrical battery cell structure shown includes an electrode assembly 10, a current collecting plate assembly 20, a shell 40 and a cover plate 31 assembly;

[0052] The motor assembly is disposed in the housing 40, and the electrode assembly 10 has a positive electrode tab 11 and a negative electrode tab 13, the positive electrode tab 11 and the negative electrode tab 13 are located on the same end surface of the electrode assembly 10, a spacer 14 is formed between the positive electrode tab 11 and the negative electrode tab 13, and a liquid storage hole 12 is provided in the middle of the electrode assembly 10 along its axis, and the liquid storage hole 12 is located in the spacer 14;

[0053] The current collecting plate assembly 20 is arranged on the motor assembly, and the current collecting plate assembly 20 includes an insulating portion 29, a positive current collecting plate 21 and a negative current collecting plate 24. The insulating portion 29 is located between the positive current collecting plate 21 and the negative current collecting plate 24. The insulating portion 29 is in conflict with the separator, and a connecting hole is opened on the insulating portion 29. The connecting hole is connected to the liquid storage hole 12. The positive current collecting plate 21 is connected to the positive electrode ear 11, and the negative current collecting plate 24 is connected to the negative electrode ear 13.

[0054] Specifically, the electrode assembly 10 includes a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet includes a positive electrode collector and a positive electrode active material. The positive electrode active material is coated on both sides of the positive electrode collector, and the coating width is less than the width of the positive electrode collector. The uncoated blank areas on both sides of the positive electrode collector serve as the tabs of the positive electrode sheet; the negative electrode sheet includes a negative electrode collector and a negative electrode active material. The negative electrode active material is coated on both sides of the negative electrode collector, and the coating width is less than the width of the negative electrode collector. The uncoated blank areas on both sides of the negative electrode collector serve as the tabs of the negative electrode sheet, and the coating width of the negative electrode sheet active material is slightly greater than the coating width of the positive electrode sheet active material; the separator is a two-layer structure, which is arranged with the positive electrode sheet and the negative electrode sheet in the manner of separator, negative electrode, separator, and positive electrode; the positive electrode sheet and the negative electrode sheet are formed after baking, rolling, and slitting. The pole piece with blank on one side is laser cut for pole ears. When cutting, the pole ears of a single electrode assembly 10 are grouped. The number of pole ears in each group is cut from small to large within the pole piece length required for a single electrode assembly 10, and the interval between each group is from small to large. The shape of a single pole ear is a parallelogram, and the gap between the pole ears is 0.1-0.5mm. Cutting in the above manner can ensure that the positive pole ear 11 and the negative pole ear 13 of the electrode assembly 10 after winding and flattening are arranged regularly according to design requirements. The positive pole ear 11 and the negative pole ear 13 of the electrode assembly 10 after winding are on the same side of the electrode assembly 10, and there is no contact between the two. There is a spacer 14, and a liquid storage hole 12 is left in the center of the electrode assembly 10 for retaining a portion of the electrolyte. The liquid storage hole 12 is a hole left by the winding needle after pulling out after winding.

[0055] The current collecting plate assembly 20 includes a positive current collecting plate 21, a negative current collecting plate 24 and an insulating portion 29, and is generally circular in shape; the positive current collecting plate 21 and the negative current collecting plate 24 have the same shape and size, but are made of different materials, and are respectively installed on both sides of the insulating portion 29, forming a symmetrical structure, and the positive electrode welding holes 23 and the negative electrode welding holes 26 are respectively designed on the surface, and the number is 3-6. The specific number can be designed according to actual needs. In this application, there are 3 positive and 3 negative holes, and the laser passes through them during welding to collect the current. The plate (ensuring that the positive current collector plate 21 and the negative current collector plate 24) are welded together with the pole ears (including the positive pole ears 11 and the negative pole ears 13), and there is a height difference of 0.1-0.5mm between the lower surface of the positive current collector plate 21 and the negative current collector plate 24 and the lower surface of the insulating portion 29 in the vertical direction, that is, the lower surface of the insulating portion 29 is the part that protrudes downward relative to the positive current collector plate 21 and the negative current collector plate 24, ensuring that the insulating portion 29 is in conflict with the electrode assembly 10, and the positive current collector plate 21 and the negative electrode are in contact with each other. The current collecting disk 24 is also designed with a positive column 22 and a negative column 25, respectively. The top of the column (including the positive column 22 and the negative column 25) is cut into a cylinder with a slightly smaller diameter. The height of the small cylinder is about 1 mm. A through hole is opened in the middle of the insulating portion 29 for liquid injection. The insulating portion 29 has a portion extending outward and located at the positive current collecting disk 21 and the negative current collecting disk 24 to cover the upper surface of the positive current collecting disk 21 and the negative current collecting disk 24 to achieve complete coverage, and according to the current collecting disk (including the positive collecting disk 21 and The position and size of the welding hole on the negative electrode current collecting plate 24 correspond to the opening of the air avoidance groove 27 of the insulating part 29. The size of the air avoidance groove 27 needs to be slightly larger than the size of the welding hole to avoid interference with the laser welding line. The insulating part 29 is designed with a coating layer 28 at the position of the pole according to the size and height of the pole. The height of the coating layer 28 is slightly higher than the height of the pole and has a thickness of about 1 mm. A stepped coating ring with a slightly larger diameter is designed on the top of the coating layer 28 for the installation of the positive conductive terminal 32 and the negative conductive terminal 33.

[0056] The shell 40 is cylindrical, with one end open and the other end closed. The open end serves as the entrance of the electrode assembly 10. When the electrode assembly 10 enters the shell, the non-ear side faces downward and enters first with the ear side facing upward. The inner diameter of the shell 40 is slightly larger than the diameter of the electrode assembly 10 to facilitate the entry of the electrode assembly 10. The wall thickness of the shell 40 is 0.5-0.8mm to ensure structural strength.

[0057] The cover plate 31 assembly is circular, including the cover plate 31 and the conductive terminal. A liquid injection hole 34 is opened in the center of the cover plate 31. The liquid injection hole 34 is designed as a step, and the diameter of the upper half is larger than the diameter of the lower half. It is used for welding the sealing nail installed on the liquid injection hole 34. A positive through hole and a negative through hole are designed on both sides of the liquid injection hole 34. The two are symmetrically arranged and are both designed as a step. The diameter of the upper half is larger than the diameter of the lower half; the conductive terminal includes a positive conductive terminal 32 and a negative conductive terminal 33, and the size and structure of the two are similar. The upper and lower parts of the positive conductive terminal 32 and the negative conductive terminal 33 are respectively designed with an upper concave portion 35 and a lower concave portion 37. The two inner concave portions do not penetrate each other, and there is a partition 36 between the two. The thickness of the partition 36 is 1 mm. The upper concave portion 35 and the lower concave portion 37 are both circular, and the inner diameter of the lower concave portion 37 is the same as the diameter of the small cylinder in the upper half of the pole (including the positive pole 22 and the negative pole 25) to ensure that the two can be installed seamlessly, and then welded together by laser penetration welding.

[0058] The present application also provides a method for preparing a battery having the above structure, and the preparation method is as follows:

[0059] S1. Laser cutting the tabs of the positive and negative electrode sheets after cutting. The cutting accuracy and spacing of the tabs must be precisely controlled during the tab cutting, and the tabs must be cut in groups and intervals according to the process requirements. The tabs are divided into multiple groups within the length of the tabs of a battery cell. The number of tabs in each group gradually increases, and the spacing between groups gradually increases. After the tab cutting of a battery cell length is completed, the same operation is performed on the tabs of each battery cell length thereafter;

[0060] S2, winding the positive electrode sheet and the negative electrode sheet with the tabs cut together with the separator, and the positive electrode tab 11 and the negative electrode tab 13 are on the same side during winding, so as to ensure that the positive electrode tab 11 and the negative electrode tab 13 of the electrode assembly 10 after winding are on the same side of the electrode assembly 10, and flattening the tabs (including the positive electrode tab 11 and the negative electrode tab 13) of the electrode assembly 10 after winding, and the tabs after flattening should be on the same horizontal plane, and the tab stacking thickness should be basically consistent, and there is a spacing area of ​​about 8-10 mm between the positive and negative electrode tabs 13 after flattening;

[0061] S3. Place the current collecting plate assembly 20 on the electrode tab side of the electrode assembly 10. It should be noted that the middle of the insulating portion 29 is placed in the spacer between the positive and negative electrode tabs 13. The positive electrode current collecting plate 21 is placed on the positive electrode tab 11, and the negative electrode current collecting plate 24 is placed on the negative electrode tab 13 to prevent the current collecting plate assembly 20 from rotating or tilting.

[0062] S4, laser welding is performed. During welding, the welding tool applies a certain pressure to the current collecting plate assembly 20 to ensure that the positive current collecting plate 21 is in close contact with the positive electrode tab 11 and the negative current collecting plate 24 is in close contact with the negative electrode tab 13 to avoid welding perforation or explosion points. The laser passes through the positive electrode welding hole 23 on the positive current collecting plate 21 to weld the positive electrode tab 11 and the positive current collecting plate 21 together. The laser passes through the negative electrode welding hole 26 on the negative current collecting plate 24 to weld the negative electrode tab 13 and the negative current collecting plate 24 together.

[0063] S5, inserting the welded electrode assembly 10 into the shell, with the non-ear side facing downwards, first entering the shell 40 until reaching the bottom of the shell 40;

[0064] S6. Place the cover plate 31 at the port 41 of the housing 40. Use the equipment welding tool to apply a certain pressure to the cover plate 31 to ensure that the two are in good contact, perform peripheral welding, and weld the two together.

[0065] S7, the semi-finished battery cell after welding needs to be sealed after baking, liquid injection, infiltration, and formation, and the sealing nail is welded to the liquid injection hole 34. At this time, the battery cell is completely sealed to ensure the internal environment of the battery cell. The sealed battery cell can be shipped after post-process testing and screening;

[0066] This completes the production process of the battery cell.

[0067] The operation based on the above-mentioned battery cell structure and method in the present application has the following advantages: compared with the current cylindrical battery cells with pole ears on both sides, the structure proposed in the present application requires that the positive and negative pole ears 13 be produced on the same side, and the positive and negative poles can be welded at the same time. It has a simple structure and high production efficiency. After the battery cell is produced, the internal resistance is small and the polarization is small, which is conducive to the electrical performance.

[0068] The positive electrode current collecting plate 21 and the negative electrode current collecting plate 24 of the above embodiment are semi-arc-shaped. Figure 10-13 As shown, in some embodiments, the difference from the first embodiment is that the shapes of the positive electrode current collecting disk 21 and the negative electrode current collecting disk 24 are different. This embodiment is designed in a shape similar to the Bagua, and the shape of the corresponding insulating portion 29 changes accordingly. In this embodiment, the pole ears are relatively more concentrated. In order to match the shape of the current collecting disk, the corresponding pole ear cutting and grouping of the positive and negative electrode sheets change accordingly. The state of the pole ears of the electrode assembly 10 after flattening is as shown in FIG. Fig.12 As shown, other structures and preparation methods are the same as those in the above embodiment.

[0069] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0070] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0071] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0072] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A cylindrical battery cell, comprising a shell (40) and an electrode assembly (10) disposed in the shell (40), characterized in that: The electrode assembly (10) comprises a positive electrode tab (11) and a negative electrode tab (13), wherein the positive electrode tab (11) and the negative electrode tab (13) are located on the same end surface of the electrode assembly (10), a spacer (14) is formed between the positive electrode tab (11) and the negative electrode tab (13), and a liquid storage hole (12) is provided in the middle of the electrode assembly (10) along its axis, and the liquid storage hole (12) is located in the spacer (14); The electrode assembly (10) is provided with a current collecting disk assembly (20), the current collecting disk assembly (20) comprising an insulating portion (29), a positive current collecting disk (21) and a negative current collecting disk (24), the insulating portion (29) being located between the positive current collecting disk (21) and the negative current collecting disk (24), the insulating portion (29) being in contact with the separator, and a connecting hole being provided on the insulating portion (29), the connecting hole being connected with the liquid storage hole (12), the positive current collecting disk (21) being connected with the positive electrode tab (11), and the negative current collecting disk (24) being connected with the negative electrode tab (13).

2. The cylindrical battery cell according to claim 1, characterized in that: The bending direction of the positive electrode tab (11) is opposite to the bending direction of the negative electrode tab (13).

3. The cylindrical battery cell according to claim 1, characterized in that: The electrode assembly (10) is formed by winding a separator, a negative electrode sheet, a separator and a positive electrode sheet which are stacked in sequence; The positive electrode sheet comprises a positive electrode current collector and a positive electrode active material coated on the positive electrode current collector, and the coating width is smaller than the width of the positive electrode current collector, and the positive electrode tab (11) is connected to a blank area of ​​the positive electrode current collector that is not coated with the positive electrode active material; The negative electrode sheet comprises a negative electrode current collector and a negative electrode active material coated on the negative electrode current collector, and the coating width is smaller than the width of the negative electrode current collector. The negative electrode tab (13) is connected to a blank area of ​​the negative electrode current collector that is not coated with the negative electrode active material.

4. The cylindrical battery cell according to claim 3, characterized in that: The coating width of the negative electrode active material is greater than the coating width of the positive electrode active material.

5. The cylindrical battery cell according to claim 1, characterized in that: There are a plurality of positive electrode tabs (11), and there is a gap between any two adjacent positive electrode tabs (11); and / or A plurality of negative electrode tabs (13) are provided, and a gap exists between any two adjacent negative electrode tabs (13).

6. The cylindrical battery cell according to claim 1, characterized in that: The diameter of the communicating hole is larger than the diameter of the liquid storage hole (12).

7. The cylindrical battery cell according to claim 1, characterized in that: The positive electrode current collecting disc (21) is provided with a positive electrode welding hole (23), and the negative electrode current collecting disc (24) is provided with a negative electrode welding hole (26).

8. The cylindrical battery cell according to claim 1, characterized in that: The positive electrode current collecting disk (21) is provided with a positive electrode column (22), and the negative electrode current collecting disk (24) is provided with a negative electrode column (25).

9. The cylindrical battery cell according to claim 1, characterized in that: It also comprises a cover plate (31), the cover plate (31) being arranged on the current collecting disc assembly, the cover plate (31) being provided with a positive electrode conductive terminal (32) connected to the positive electrode current collecting disc (21), and the cover plate (31) being provided with a negative electrode conductive terminal (33) connected to the negative electrode current collecting disc (24); The cover plate (31) is provided with a liquid injection hole (34), and a positive electrode through hole and a negative electrode through hole are provided on both sides of the liquid injection hole (34).

10. A method for preparing a cylindrical battery, characterized in that: The method for producing a cylindrical battery cell according to any one of claims 1 to 9 comprises the following steps: S1, laser cutting the cut positive electrode sheet and negative electrode sheet to form a positive electrode tab (11) and a negative electrode tab (13); S2, winding the cut positive electrode sheet, negative electrode sheet and separator together, with the positive electrode tab (11) and the negative electrode tab (13) on the same side during winding, to ensure that the positive and negative electrode tabs (13) of the electrode assembly (10) are on the same side of the electrode assembly (10) after winding, flattening the tabs of the electrode assembly (10) after winding, and the tabs after flattening need to be on the same horizontal plane, and the tab stacking thickness is basically the same, and there is a spacing area of ​​about 8-10 mm between the positive electrode tab (11) and the negative electrode tab (13) after flattening; S3, placing the current collecting plate assembly (20) on the electrode tab side of the electrode assembly (10), placing the middle part of the insulating portion (29) in the spacer between the positive and negative electrode tabs (13), placing the positive electrode current collecting plate (21) on the positive electrode tab (11), and placing the negative electrode current collecting plate (24) on the negative electrode tab (13); S4, performing laser welding, during which the welding tool applies a certain pressure to the collector plate assembly (20) to ensure that the collector plate is in close contact with the tab; S5, inserting the welded electrode assembly (10) into the shell (40), with the non-electrode ear side facing downward first entering the shell (40) until reaching the bottom of the shell (40); S6. Place the cover plate (31) at the opening of the housing (40), apply a certain pressure to the cover plate (31) using a welding tool to ensure that the two are in good contact, perform peripheral welding, and weld the two together to form a battery cell; S7. After being baked, injected, soaked and formed, the semi-finished battery cell after welding needs to be sealed and welded, and the sealing pin is welded to the injection hole (34).

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