Bare battery cell, cylindrical battery and cylindrical battery assembly method

Abstract

The present invention discloses a bare battery cell, comprising a positive electrode sheet, a diaphragm layer and a negative electrode sheet stacked and wound to form a cylinder, the negative electrode sheet comprising a negative electrode coating region and a negative electrode ear arranged at the lower side of the negative electrode coating region in the width direction, the negative electrode sheet is further provided with a metal region integrally provided with the negative electrode coating region and the negative electrode ear in the length direction, the upper side of the metal region in the width direction of the negative electrode coating region is higher than the upper side of the negative electrode coating region in the width direction; the positive electrode sheet comprises a positive electrode coating region and a positive electrode ear arranged at the upper side of the positive electrode coating region in the width direction, the length of the positive electrode ear is less than the length of the positive electrode coating region, and a gap is provided between the positive electrode ear and the metal foil layer. The present invention arranges a metal foil layer to lead the negative electrode ear at the lower end of the bare battery cell to the upper end of the bare battery cell, thereby realizing the same end output of the positive and negative electrodes of the bare battery cell, thereby avoiding the series connection of the shell resistance, and improving the high rate performance of the cylindrical power battery, the charge and discharge temperature rise, etc.

Description

Technical Field

[0001] The present invention relates to the field of cylindrical batteries, and in particular to a bare battery cell, a cylindrical battery and an assembly method of a cylindrical battery. Background Art

[0002] At present, lithium-ion / sodium-ion cylindrical batteries have gradually become mainstream products in the new energy industry due to their high energy density and good capacity consistency. Among them, the full-electrode / collector plate structure has been determined by more and more manufacturers as the preferred direction of cylindrical battery structure. Common questions:

[0003] 1. The current collector of conventional cylindrical power batteries is directly inserted into the shell for side wall welding assembly. The current collector is also welded to the other end of the bare cell and is connected to the bottom of the shell only by resistance welding with a small welding area. That is, the positive and negative electrodes of the battery are connected in series with the shell resistance, resulting in a relatively large resistance value of the cylindrical battery. It is difficult to achieve high-rate charging and discharging, and the temperature rise is also relatively large.

[0004] 2. It is difficult to implement explosion-proof valve pressure relief for cylindrical power batteries, because one end of the pole is too small to implement an explosion-proof valve, and the middle of the other end is fixed to the bottom of the shell by resistance welding, so an explosion-proof valve cannot be implemented either. Therefore, it will bring safety problems. Summary of the invention

[0005] The purpose of the present invention is to provide a bare cell, a cylindrical battery and an assembly method of a cylindrical battery, so as to realize the same-end output of the positive and negative electrodes of the bare cell, thereby avoiding the series connection of the shell resistance, reducing the resistance of the cylindrical battery to improve the high-rate performance of the cylindrical power battery and the problem of charge and discharge temperature rise.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a bare battery cell, comprising a positive electrode sheet, a separator layer and a negative electrode sheet stacked and wound to form a cylinder, the negative electrode sheet comprising a negative electrode coating area and a negative electrode ear arranged on the lower side of the negative electrode coating area in the width direction, the negative electrode sheet is also provided with a metal region integrally arranged with the negative electrode coating area and the negative electrode ear in its length direction, the upper side edge of the metal region in the width direction of the negative electrode coating area is higher than the upper side edge of the negative electrode coating area in the width direction so that the metal region is located on the outside of the bare battery cell and forms a metal foil layer; the positive electrode sheet comprises a positive electrode coating area and a positive electrode ear arranged on the upper side of the positive electrode coating area in the width direction, the positive electrode ear is located on the upper side of the bare battery cell, the negative electrode ear is located on the lower side of the bare battery cell, the length of the positive electrode ear is less than the length of the positive electrode coating area, and a gap is provided between the positive electrode ear and the metal foil layer.

[0007] Preferably, at least one stress relief notch is provided at the upper end of the metal foil layer.

[0008] Preferably, the number of the metal foil layers is greater than or equal to 5 and less than or equal to 15.

[0009] The present invention also provides a cylindrical battery, comprising: a shell, wherein an opening is provided at the upper end of the shell; the above-mentioned bare battery cell, wherein the bare battery cell is arranged inside the shell; a side wall welding ring, wherein the side wall welding ring is installed in the gap, wherein the side wall welding ring comprises an annular body and a vertical side formed by extending and bending the annular body, wherein an annular insulating rubber layer is provided on the side of the annular body facing away from the vertical side, wherein the annular body is arranged around the outer periphery of the positive electrode ear, and the vertical side is fitted with the inner side of the metal foil layer so that the shell, the metal foil layer and the vertical side of the side wall welding ring are welded and connected, and the insulating rubber layer separates the annular body and the positive electrode ear; and a cover plate assembly, wherein the cover plate assembly covers the opening and is sealed and connected to the shell.

[0010] Preferably, the bottom of the shell is closed, and an explosion-proof valve portion is provided at the bottom of the shell.

[0011] Preferably, a pole is provided on the cover plate assembly, a positive current collecting disk is connected to the positive ear, an insulating gasket is also provided above the positive current collecting disk, the insulating gasket is in an inverted U shape, the insulating gasket includes a groove bottom and a groove wall connected to the groove bottom, the groove wall is pressed against the upper side surface of the annular body, the groove bottom is abutted against the cover plate assembly to limit the bare battery cell, and an avoidance opening is opened in the middle of the groove bottom to form an avoidance position for the pole.

[0012] Preferably, a hollow opening is provided at the connection between the annular body and the vertical side.

[0013] Preferably, when the shell is a steel shell, the metal foil layer is a copper foil layer, the negative electrode tab is a copper foil full tab, and the positive electrode tab is an aluminum foil full tab; or when the shell is an aluminum shell, the metal foil layer is an aluminum foil layer, the negative electrode tab is an aluminum foil full tab, and the positive electrode tab is a copper foil full tab.

[0014] The present invention also provides an assembly method for a cylindrical battery, comprising the following steps: providing the above-mentioned bare battery cell, wherein the positive electrode sheet and the negative electrode sheet of the bare battery cell are flattened or patted; welding and fixing the negative electrode ear of the bare battery cell to the negative electrode collector plate; providing a shell, wherein an opening is provided at the upper end of the shell, and the bare battery cell is installed in the shell, and the positive electrode ear is located at the upper end of the shell, and the negative electrode ear is located at the lower end of the shell; providing a side wall welding ring, wherein the side wall welding ring comprises an annular body and a vertical side formed by extending and bending the annular body, an annular insulating rubber layer is provided on the side of the annular body facing away from the vertical side, and the side wall welding ring is installed in the gap so that the annular body is arranged around the outer periphery of the positive electrode ear and the vertical side is in contact with the inner side of the metal foil layer; and the shell, the metal foil layer and the vertical side of the side wall welding ring are welded and connected by laser welding or ultrasonic welding.

[0015] Preferably, after the step of welding and connecting the shell, the metal foil layer and the vertical sides of the side wall welding ring by laser welding or ultrasonic welding, the following steps are also included: welding and fixing the positive electrode ear to the positive electrode collector disk by laser penetration welding, and the insulating adhesive layer isolates and insulates the positive electrode collector disk and the side wall welding ring; providing a cover plate assembly and an insulating gasket, wherein the cover plate assembly is provided with a pole, and the insulating gasket is in an inverted U shape, including a groove bottom and a groove wall connected to the groove bottom, and the groove wall is pressed against the groove bottom. The upper side surface of the annular body is provided with the groove bottom and the cover plate assembly abutted against each other to limit the bare battery cell, and an escape opening is provided in the middle of the groove bottom to form an escape position for the pole; the cover plate assembly and the upper end of the shell are sealed by laser welding; an injection hole is provided at the bottom of the shell, a clamp is used to pass through the injection hole and support the middle position of the positive current collector to fix the pole and the positive current collector by laser penetration welding; liquid is injected through the injection hole, and a sealing nail is used to seal the injection hole.

[0016] Compared with the prior art, the present invention arranges a metal foil layer to lead the negative electrode ear at the lower end of the bare battery cell to the upper end of the bare battery cell, thereby achieving the same-end output of the positive and negative electrodes of the bare battery cell, thereby avoiding the series connection of the shell resistance, reducing the resistance of the cylindrical battery, and improving the high-rate performance of the cylindrical power battery, charging and discharging temperature rise, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of the positive electrode sheet of the bare battery cell of the present invention.

[0018] Figure 2 It is a schematic structural diagram of the negative electrode sheet of the bare battery cell of the present invention.

[0019] Figure 3 It is a structural schematic diagram of a bare battery cell of the present invention at one angle.

[0020] Figure 4 It is a schematic structural diagram of a bare battery cell of the present invention from another angle.

[0021] Figure 5 It is a schematic diagram of the three-dimensional structure of the side wall welding ring in the cylindrical battery of the present invention.

[0022] Figure 6 It is a schematic diagram of the top view of the side wall welding ring in the cylindrical battery of the present invention.

[0023] Figure 7 It is a schematic diagram of the cross-sectional structure of the side wall welding ring in the cylindrical battery of the present invention.

[0024] Figure 8 It is a schematic diagram of the structure of the cylindrical battery of the present invention after the side wall welding ring and the bare battery core are installed in the shell.

[0025] Fig. 9 For Figure 8 Schematic diagram of the structure after the positive electrode current collecting plate is installed on the foundation.

[0026] Fig.10 It is a structural schematic diagram of a cylindrical battery of the present invention at one angle.

[0027] Fig.11 It is a schematic structural diagram of the cylindrical battery of the present invention from another angle.

[0028] Fig.12 It is a schematic diagram of the cross-sectional structure of the cylindrical battery of the present invention.

[0029] Fig.13 for Fig.12 Enlarged view of point C in the middle. DETAILED DESCRIPTION

[0030] In order to explain the technical content, structural features and achieved effects of the present invention in detail, the following is a detailed description in conjunction with the implementation methods and the accompanying drawings.

[0031] like Figures 1 to 4 As shown, the present invention provides a bare battery cell 10, including a positive electrode sheet 1, a separator layer and a negative electrode sheet 2 stacked and wound to form a cylinder, the negative electrode sheet 2 includes a negative electrode coating area 21 and a negative electrode ear 22 arranged at the lower side of the negative electrode coating area 21 in the width direction, and the negative electrode sheet 2 is also provided with a metal area 23 integrally arranged with the negative electrode coating area 21 and the negative electrode ear 22 in the length direction, and the upper side of the metal area 23 in the width direction of the negative electrode coating area 21 is higher than the negative electrode coating area 21 On its upper side in the width direction, the metal area 23 is located on the outside of the bare battery cell 10 and forms a metal foil layer 25; the positive electrode sheet 1 includes a positive electrode coating area 11 and a positive electrode ear 12 arranged on the upper side of the positive electrode coating area 11 in the width direction, the positive electrode ear 12 is located on the upper side of the bare battery cell 10, and the negative electrode ear 22 is located on the lower side of the bare battery cell 10. The length of the positive electrode ear 12 is less than the length of the positive electrode coating area 11, and a gap is provided between the positive electrode ear 12 on the bare battery cell 10 and the metal foil layer 25.

[0032] Specifically, Figure 1 to Figure 2 As shown, arrows A and B indicate the winding feeding direction and the direction along the arrows represents the front. Figure 2 As shown, the foil material in the front area above the negative electrode coating area 21 of the negative electrode sheet 2 is removed by laser, and only the foil material in the second tail area 24 above the negative electrode coating area 21 is retained. At the same time, the foil material area of ​​a preset length behind the negative electrode coating area 21 is retained to form a required number of metal foil layers 25; as shown in FIG. Figure 1As shown, the foil material of the first tail area 13 above the positive electrode coating area 11 of the positive electrode sheet 1 is cut off by laser, and the foil material of the side and the bottom of the positive electrode coating area 11 of the positive electrode sheet 1 are cut off by laser, and the length and width of the negative electrode coating area 21 are slightly larger than the length and width of the positive electrode coating area 11, so that the powder material of the negative electrode coating area 21 can cover the powder material of the positive electrode coating area 11, because part of the foil material of the second tail area 24 above the negative electrode coating area 21 is retained, and at the same time, the foil material area of ​​the preset length behind the negative electrode coating area 21 is retained, therefore, the upper end surface of the metal foil layer 25 is higher than the upper end surface of the negative electrode coating area 21 and The upper end surface of the flattened positive electrode ear 12. In addition, the wound positive electrode ear 12 is located in the middle of the upper end of the bare battery cell 10, so that a gap is provided between the positive electrode ear 12 and the metal foil layer 25. The width of the diaphragm layer is set corresponding to the width of the negative electrode coating area 21, which is generally 1 mm to 1.5 mm wider than the single side of the negative electrode coating area 21. The length of the diaphragm layer is set corresponding to the length of the negative electrode coating area 21, which is generally 3 mm to 5 mm longer than the negative electrode coating area 21. Of course, the specific setting of the diaphragm layer is subject to actual needs. When the bare battery cell 10 is wound, the negative electrode sheet 2 is located at the outermost side, and the diaphragm layer and the positive electrode sheet 1 are stacked in sequence on the negative electrode sheet 2 to form a cylinder. Figures 1 to 4 As shown; after winding, the positive electrode ear 12, the upper end of the separator layer, and the negative electrode ear 22 are flattened or patted.

[0033] In the embodiment of the present invention, a metal foil layer 25 is provided to lead the negative electrode ear 22 at the lower end of the bare battery cell 10 to the upper end of the bare battery cell 10, so that the positive and negative electrodes of the bare battery cell 10 are output at the same end, thereby avoiding the resistance connected in series to the shell 30, reducing the resistance of the cylindrical battery, and improving the high-rate performance of the cylindrical power battery, the charge and discharge temperature rise, etc.

[0034] In the embodiment of the present invention, Figure 3 to Figure 4 As shown, at least one stress release notch 251 is provided at the upper end of the metal foil layer 25. Specifically, the stress release notch 251 is U-shaped, and there may be three stress release notches 251 evenly arranged. The specific number is set according to actual needs and is not limited here. The stress generated by the winding of the metal foil layer 25 can be released through the stress release notch 251, so that the structure of the metal foil layer 25 is more stable.

[0035] In the embodiment of the present invention, the number of metal foil layers 25 is greater than or equal to 5 and less than or equal to 15. The specific number of layers is selected according to actual needs, as long as the electrical performance of the cylindrical battery and the size requirements of the cylindrical battery are guaranteed.

[0036] like Figures 5 to 13As shown, an embodiment of the present invention further discloses a cylindrical battery, comprising: a shell 30, a bare cell 10, a side wall welding ring 20 and a cover plate assembly 40, wherein an opening is provided at the upper end of the shell 30; the bare cell 10 is arranged inside the shell 30; the side wall welding ring 20 is installed in the gap, the side wall welding ring 20 comprises an annular body 201 and a vertical side 202 formed by extending and bending the annular body 201, a side of the annular body 201 facing away from the vertical side 202 is provided with an annular insulating rubber layer 203, the annular body 201 is arranged around the outer periphery of the positive ear 12, and the vertical side 202 is fitted with the inner side of the metal foil layer 25 so that the shell 30, the metal foil layer 25 and the vertical side 202 of the side wall welding ring 20 are welded and connected, the insulating rubber layer 203 separates the annular body 201 and the positive ear 12, and the cover plate assembly 40 covers the opening and is sealed and connected to the shell 30.

[0037] Specifically, the structure of the bare cell 10 is as described above and will not be repeated here. The vertical edge 202 is formed on the outer edge of the annular body 201. By setting the side wall welding ring 20 in the gap and using ultrasonic welding or laser welding to weld the shell 30, the metal foil layer 25 and the vertical edge 202 of the side wall welding ring 20, the insulating glue layer 203 can be used to isolate and insulate the positive ear 12 and the side wall welding ring 20, so that the positive and negative electrodes of the bare cell 10 can be output at the same end. At the same time, ultrasonic welding or laser welding with a larger welding area is used instead of resistance welding with a smaller welding area to avoid the resistance of the shell 30, reduce the battery resistance, and improve the high-rate performance of the cylindrical power battery and the temperature rise of charging and discharging.

[0038] In the embodiment of the present invention, Fig.11 As shown, an opening is provided at the upper end of the shell 30 and the bottom of the shell 30 is closed, and an explosion-proof valve portion 301 is provided at the bottom of the shell 30. Specifically, the negative electrode sheet 2 is welded to the negative electrode current collecting disk, and in the present invention, the negative electrode current collecting disk does not need to be welded to the bottom of the shell 30. Therefore, an explosion-proof valve portion 301 can be provided at the bottom of the shell 30 to increase the safety performance of the cylindrical battery.

[0039] In the embodiment of the present invention, Figures 10 to 13 As shown, a pole 401 is provided on the cover plate assembly 40, a positive current collector 50 is connected to the positive ear 12, and an insulating gasket 60 is also provided above the positive current collector 50. The insulating gasket 60 is in an inverted U shape, and the insulating gasket 60 includes a groove bottom 602 and a groove wall 601 connected to the groove bottom 602. The groove wall 601 is pressed against the upper side of the annular body 201. The groove bottom 602 is in contact with the cover plate assembly 40 to limit the bare cell 10. A clearance opening is provided in the middle of the groove bottom 602 to form a clearance position for the installation of the pole 401. The position of the bare cell 10 in the axial direction is further limited by using the insulating gasket 60 to prevent the axial movement of the bare cell 10 from affecting the welding effect between the bare cell 10 and the shell 30.

[0040] In the embodiment of the present invention, a hollow opening 205 is provided at the connection between the annular body 201 and the vertical side 202. Figures 5 to 7 As shown, the annular body 201 is circular, and the hollow opening 205 is arranged at the connection between the vertical side 202 and the annular body 201. The insulating rubber layer 203 covers the inner side of the annular body 201. The insulating rubber can be coated on the inner side of the annular body 201 by the rubber coating injection molding process. The material of the annular body 201 and the vertical side 202 in the embodiment of the present invention are both metal. The metal foil layer 25 integrally arranged with the negative electrode ear 22 of the bare battery cell 10 can be connected through the vertical side 202 to perform side wall welding in the form of laser welding or ultrasonic welding. Since the hollow opening 205 is provided, the hollow opening 205 has an adaptive feature. When the vertical side 202 is subjected to side wall welding, the vertical side 202 is adaptively attached to the metal foil layer 25 through the hollow opening 205 to ensure the consistency of the welding area.

[0041] In the embodiment of the present invention, the vertical edges 202 are spaced apart and there are at least two of them, and the angle b formed by the line connecting the two side edges of the vertical edge 202 and the center of the annular body 201 is greater than or equal to 5 degrees and less than or equal to 90 degrees. Figures 5 and 6 As shown, there are three evenly distributed vertical edges 202. The welding area can be increased and different welding areas can be formed by multiple vertical edges 202, so that the welding effect is better and the welding is more solid. Of course, the specific setting form and number of the vertical edges 202 can be set according to actual needs. The vertical edges 202 can also be set on the continuous entire ring surface of the annular body 201, rather than being set at intervals.

[0042] In the embodiment of the present invention, Figures 5 and 6 As shown, the annular body 201 is provided with at least one inwardly recessed positioning groove 204 on one side of the vertical side 202, and the positioning groove 204 is spaced apart from the vertical side 202. Specifically, there are three positioning grooves 204, which can be used for positioning and facilitate the installation of the side wall welding ring 20, and the design is very clever.

[0043] In the embodiment of the present invention, Figure 7 As shown, the thickness T of the vertical edge 202 is greater than or equal to 0.1 mm and less than or equal to 0.5 mm. This thickness is convenient for welding and does not occupy too much space, which is beneficial for practical use.

[0044] In the embodiment of the present invention, Figure 6 As shown, the angle a formed by the line connecting the two side edges of the hollow opening 205 and the center of the annular body 201 is smaller than the angle b formed by the line connecting the two side edges of the vertical side 202 and the center of the annular body 201, and the width c of the hollow opening 205 in the diameter direction of the annular body 201 is greater than or equal to 0.5 mm.

[0045] In some other embodiments of the present invention, the hollow opening 205 can also be arranged at the bottom of the vertical edge 202 or the hollow opening 205 can be arranged on the annular body 201. When the hollow opening 205 is arranged on the annular body 201, the horizontal distance between the hollow opening 205 and the vertical edge 202 is less than or equal to 2 mm.

[0046] In the embodiment of the present invention, Figure 7 As shown, the width W of the insulating rubber layer 203 in the radial direction of the annular body 201 is greater than or equal to 1 mm. By providing an insulating rubber layer 203 of a certain width, the insulation with the positive electrode ear 12 provided inside the annular body 201 can be improved, thereby increasing the stability of the cylindrical battery.

[0047] In the embodiment of the present invention, the materials of the annular body 201 and the vertical edge 202 are both metal, and the metal is copper or nickel or a copper-nickel composite strip.

[0048] By setting a hollow opening 205 on the cylindrical battery side wall welding ring 20 to form an adaptive feature, when the vertical edge 202 and the metal foil layer 25 are attached to the inner wall of the shell 30 and the side wall welding is performed by laser welding or ultrasonic welding, the vertical edge 202 is adaptively attached to the shell 30 through the hollow opening 205, thereby ensuring the consistency of the welding area.

[0049] In the embodiment of the present invention, when the shell 30 is a steel shell, the metal foil layer 25 is a copper foil layer, the negative electrode tab 22 is a copper foil full tab, and the positive electrode tab 12 is an aluminum foil full tab.

[0050] In some other embodiments of the present invention, when the shell 30 is an aluminum shell, the polarity is reversed, that is, the metal foil layer 25 is an aluminum foil layer, the negative electrode tab 22 becomes an aluminum foil full tab, and the positive electrode tab 12 becomes a copper foil full tab.

[0051] like Figures 3 to 13 As shown, an embodiment of the present invention also provides a method for assembling a cylindrical battery, comprising the following steps:

[0052] S1, providing a bare cell 10 of the above structure, wherein the positive electrode tab 12 and the negative electrode tab 22 of the bare cell 10 are flattened or patted; specifically, Figure 4 and Figure 5 As shown, after the positive electrode sheet 1, the separator layer and the negative electrode sheet 2 are stacked and wound to form a cylinder, the positive electrode tab 12 in the middle of the upper end of the bare battery cell 10 is flattened or patted, and the negative electrode tab 22 is flattened or patted.

[0053] S2, welding and fixing the negative electrode tab 22 of the bare battery cell 10 to the negative electrode collector disk. Specifically, laser penetration welding can be used to weld and fix the negative electrode tab 22 of the bare battery cell 10 to the negative electrode collector disk.

[0054] S3, such as Figure 8As shown, a shell 30 is provided, and an opening is set at the upper end of the shell 30. The bare battery cell 10 is installed in the shell 30, and the positive electrode ear 12 is located at the upper end of the shell 30, and the negative electrode ear 22 is located at the lower end of the shell 30.

[0055] S4, such as Figures 5 to 7 As shown, a side wall welding ring 20 is provided, and the side wall welding ring 20 includes an annular body 201 and a vertical side 202 formed by extending and bending the annular body 201, and an annular insulating rubber layer 203 is provided on the side of the annular body 201 facing away from the vertical side 202. The side wall welding ring 20 is installed in the gap so that the annular body 201 is arranged around the outer periphery of the positive electrode ear 12 and the vertical side 202 is in contact with the inner side of the metal foil layer 25. Specifically, the specific structure of the side wall welding ring 20 is as described above and will not be repeated here. The annular body 201 of the side wall welding ring 20 is arranged above the positive electrode coating area 11 and the negative electrode coating area 21.

[0056] S5. Use laser welding or ultrasonic welding to weld and connect the shell 30, the metal foil layer 25 and the vertical edge 202 of the side wall welding ring 20.

[0057] In the embodiment of the present invention, after the step S5 of welding and connecting the housing 30, the metal foil layer 25 and the vertical edge 202 of the side wall welding ring 20 by laser welding or ultrasonic welding, the following steps are also included:

[0058] S6, such as Fig. 9 As shown, the positive electrode ear 12 is welded and fixed to the positive electrode current collecting disc 50 by laser penetration welding, and the insulating glue layer 203 isolates and insulates the positive electrode current collecting disc 50 and the side wall welding ring 20 .

[0059] S7. Provide a cover assembly 40 and an insulating gasket 60. The cover assembly 40 is provided with a pole 401. The insulating gasket 60 is in an inverted U shape, including a groove bottom 602 and a groove wall 601 connected to the groove bottom 602. The groove wall 601 is pressed against the upper side surface of the annular body 201 and the groove bottom 602 is abutted against the cover assembly 40 to limit the bare battery cell 10. An escape opening is opened in the middle of the groove bottom 602 to form an escape position for the pole 401.

[0060] S8. The cover plate assembly 40 and the upper end of the shell 30 are sealed by laser welding. Specifically, the edge of the cover plate assembly 40 is matched with the upper end of the shell 30 and sealed by laser welding.

[0061] S9. A liquid injection hole is provided at the bottom of the shell 30. A clamp is used to pass through the liquid injection hole and support the middle position of the positive electrode current collecting disc 50 to connect and fix the pole 401 and the positive electrode current collecting disc 50 by laser penetration welding.

[0062] S10, injecting liquid into the liquid injection hole, and sealing the liquid injection hole with a sealing nail.

[0063] In the embodiment of the present invention, positive and negative pole ears are arranged at both ends of the bare cell 10 of the cylindrical battery and a metal foil layer 25 structure is arranged on the outside. The negative ear 22 at the bottom of the bare cell 10 is welded to the negative current collector, the side wall welding ring 20 is attached to the inner wall of the shell 30 with the outer metal foil layer 25 by means of the adaptive hollow opening 205 and the side wall welding is performed, the positive current collector 50 on the inside of the side wall welding ring 20 is laser welded to the positive ear 12, and the insulating plastic layer 203 on the inner edge of the side wall welding ring 20 isolates and insulates the positive current collector 50 and the side wall welding ring 20, so as to finally realize that the positive and negative poles of the bare cell 10 are output at the same end, and ultrasonic welding or laser welding with a larger welding area is used instead of resistance welding with a smaller welding area to avoid the resistance of the shell 30 and reduce the battery resistance. At the same time, the safety valve function of the explosion-proof valve part 301 can be implemented at the bottom of the shell 30, so as to improve the high-rate performance, charge and discharge temperature rise, and safety of the cylindrical power battery.

[0064] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention still fall within the scope covered by the present invention.

Claims

1. A cylindrical battery, characterized in that: include: A shell, wherein an opening is provided at an upper end of the shell; A bare battery cell, wherein the bare battery cell comprises a positive electrode sheet, a separator layer and a negative electrode sheet stacked and wound to form a cylinder, wherein the negative electrode sheet comprises a negative electrode coating region and a negative electrode ear arranged at the lower side of the negative electrode coating region in the width direction, and the negative electrode sheet is further provided with a metal region integrally arranged with the negative electrode coating region and the negative electrode ear in the length direction, wherein the upper side edge of the metal region in the width direction of the negative electrode coating region is higher than the upper side edge of the negative electrode coating region in the width direction so that the metal region is located outside the bare battery cell and forms a metal foil layer The positive electrode sheet comprises a positive electrode coating region and a positive electrode ear arranged on the upper side of the positive electrode coating region in the width direction, the positive electrode ear is located on the upper side of the bare battery cell, the negative electrode ear is located on the lower side of the bare battery cell, the length of the positive electrode ear is less than the length of the positive electrode coating region, the positive electrode ear and the negative electrode ear are both full-pole ears, the positive electrode ear after winding is located in the middle of the upper end of the bare battery cell, a gap is provided between the positive electrode ear and the metal foil layer, and the negative electrode ear is used for welding and fixing with the negative electrode collector; the bare battery cell is arranged inside the shell; A side wall welding ring, the side wall welding ring is installed in the gap, the side wall welding ring comprises an annular body and a vertical side formed by extending and bending the annular body, a side of the annular body facing away from the vertical side is provided with an annular insulating rubber layer, the annular body is arranged around the outer periphery of the positive electrode ear, and the vertical side is fitted with the inner side of the metal foil layer so that the shell, the metal foil layer and the vertical side of the side wall welding ring are welded and connected, and the insulating rubber layer separates the annular body and the positive electrode ear; A cover plate assembly covers the opening and is sealed with the shell.

2. The cylindrical battery according to claim 1, characterized in that: At least one stress release notch is provided at the upper end of the metal foil layer.

3. The cylindrical battery according to claim 1, characterized in that: The number of the metal foil layers is greater than or equal to 5 and less than or equal to 15.

4. The cylindrical battery according to claim 1, characterized in that: The bottom of the shell is closed, and an explosion-proof valve portion is provided at the bottom of the shell.

5. The cylindrical battery according to claim 1, characterized in that: The cover plate assembly is provided with a pole, the positive electrode ear is connected to a positive current collecting disk, an insulating gasket is also provided above the positive current collecting disk, the insulating gasket is in an inverted U shape, the insulating gasket includes a groove bottom and a groove wall connected to the groove bottom, the groove wall is pressed against the upper side surface of the annular body, the groove bottom is abutted against the cover plate assembly to limit the bare battery cell, and an avoidance opening is opened in the middle of the groove bottom to form an avoidance position for the pole.

6. The cylindrical battery according to claim 1, characterized in that: A hollow opening is provided at the connection between the annular body and the vertical side.

7. The cylindrical battery according to claim 1, characterized in that: When the shell is a steel shell, the metal foil layer is a copper foil layer, the negative electrode tab is a copper foil full tab, and the positive electrode tab is an aluminum foil full tab; or When the shell is an aluminum shell, the metal foil layer is an aluminum foil layer, the negative electrode tab is an aluminum foil full tab, and the positive electrode tab is a copper foil full tab.

8. A method for assembling a cylindrical battery, characterized in that: The steps include: A bare battery cell is provided, wherein the bare battery cell comprises a positive electrode sheet, a separator layer and a negative electrode sheet stacked and wound to form a cylinder, wherein the negative electrode sheet comprises a negative electrode coating region and a negative electrode ear arranged at the lower side of the negative electrode coating region in the width direction, and the negative electrode sheet is further provided with a metal region integrally arranged with the negative electrode coating region and the negative electrode ear in the length direction, wherein the upper side edge of the metal region in the width direction of the negative electrode coating region is higher than the upper side edge of the negative electrode coating region in the width direction so that the metal region is located outside the bare battery cell and forms a metal foil layer; The positive electrode sheet includes a positive electrode coating area and a positive electrode ear arranged on the upper side of the positive electrode coating area in the width direction, the positive electrode ear is located on the upper side of the bare battery cell, the negative electrode ear is located on the lower side of the bare battery cell, the length of the positive electrode ear is less than the length of the positive electrode coating area, the positive electrode ear and the negative electrode ear are both full-pole ears, the positive electrode ear after winding is located in the middle of the upper end of the bare battery cell, a gap is provided between the positive electrode ear and the metal foil layer, the negative electrode ear is used to be welded and fixed to the negative electrode collector plate, and the positive electrode ear and the negative electrode ear of the bare battery cell are flattened or flattened; Welding and fixing the negative electrode ear of the bare battery cell to the negative electrode current collector; A shell is provided, wherein an opening is provided at the upper end of the shell, and the bare cell is installed in the shell, with the positive electrode ear located at the upper end of the shell and the negative electrode ear located at the lower end of the shell; A side wall welding ring is provided, the side wall welding ring comprising an annular body and a vertical side formed by extending and bending the annular body, a side of the annular body facing away from the vertical side is provided with an annular insulating rubber layer, and the side wall welding ring is installed in the gap so that the annular body is arranged around the outer periphery of the positive electrode ear and the vertical side is in contact with the inner side of the metal foil layer; The shell, the metal foil layer and the vertical edges of the side wall welding ring are welded and connected by laser welding or ultrasonic welding.

9. The method for assembling a cylindrical battery as claimed in claim 8, characterized in that After the step of welding and connecting the shell, the metal foil layer and the vertical edges of the side wall welding ring by laser welding or ultrasonic welding, the following steps are also included: The positive electrode ear is welded and fixed to the positive electrode collector plate by laser penetration welding, and the insulating rubber layer isolates and insulates the positive electrode collector plate and the side wall welding ring; A cover plate assembly and an insulating gasket are provided, wherein the cover plate assembly is provided with a pole, the insulating gasket is in an inverted U shape, and comprises a groove bottom and a groove wall connected to the groove bottom, the groove wall is pressed against the upper side surface of the annular body and the groove bottom is abutted against the cover plate assembly to limit the bare battery cell, and an avoidance opening is provided in the middle of the groove bottom to form an avoidance position for the pole; The cover plate assembly and the upper end of the shell are sealed by laser welding; The bottom of the shell is provided with a liquid injection hole, and a clamp is used to pass through the liquid injection hole and support the middle position of the positive electrode collector plate to fix the pole and the positive electrode collector plate by laser penetration welding; Liquid is injected through the injection hole, and the injection hole is sealed with a sealing nail.

Images