A cylindrical secondary battery

Abstract

The utility model relates to a cylindrical battery technical field, proposes a kind of cylindrical secondary battery, including roll core, positive current collector and negative current collector, the both ends of roll core are respectively provided with positive electrode lug and negative electrode lug;The positive current collector includes positive disc body, and the positive disc body is fixed with the positive electrode lug by multiple positive welding marks welding;The negative current collector is fixed with the negative electrode lug by multiple negative welding marks welding;13.3%≤S 100 / S0≤17.7%; the area of the negative current collector is S 20 , the span of the negative welding mark along its length direction is L 20 , the span of the negative welding mark along its width direction is W 20 , the area of each negative welding mark is S 200 , the area of multiple negative welding marks is S 2000 , S 200 =L 20 ·W 20 , 10%≤S 2000 / S 20 ≤20%.The utility model limits the setting area of positive welding mark and negative welding mark, can consider the welding effect and the flow capacity of current collector welding position, to effectively improve the overall performance of battery.

Description

Technical Field

[0001] This utility model relates to the field of cylindrical battery technology, and in particular to a cylindrical secondary battery. Background Technology

[0002] With the rapid development of technology, the demand for energy storage in various electronic devices, electric vehicles, and energy storage systems is increasing. Rechargeable batteries, due to their rechargeable nature, have become a key energy solution to meet these needs. Among them, cylindrical rechargeable batteries, with their compact structure, high energy density, and mature manufacturing processes, have been widely used in numerous application scenarios.

[0003] Cylindrical secondary batteries mainly consist of a casing, a core, and positive and negative current collectors. The positive and negative current collectors are welded and fixed to the positive and negative electrode tabs of the core using methods such as laser welding and ultrasonic welding, respectively, to collect and conduct current. For example, the invention patent with publication number CN114473210B discloses a current collector structure and welding method for a circular lithium-ion battery. To achieve welding of the positive and negative current collectors to other components, welding areas are provided on both the positive and negative current collectors, allowing them to be welded to other components within these areas.

[0004] The area of ​​the welding region directly affects the overall performance of the battery. The above technical solution does not reasonably set the area of ​​the welding region. If the area of ​​the welding region is too small, the current flow area at the welding position is small, the internal resistance of the battery increases, which may lead to concentrated heat generation at the welding position, resulting in excessive rate temperature rise. At the same time, an excessively small welding area will also reduce the welding strength and affect the connection quality. If the area of ​​the welding region is too large, the welding position is prone to deviating from the weldable area on the current collector, resulting in some welding wires being invalid or the battery being scrapped. At the same time, a larger welding region will also increase the welding time, leading to a decrease in welding efficiency and an increase in battery manufacturing costs. Utility Model Content

[0005] In view of this, the present invention proposes a cylindrical secondary battery. By reasonably setting the area ratio of the positive electrode solder and the negative electrode solder, the welding effect and current carrying capacity of the welding position can be taken into account, thereby effectively improving the overall performance of the battery.

[0006] The technical solution of this utility model is achieved as follows: This utility model provides a cylindrical secondary battery, including a core, a positive current collector, and a negative current collector, wherein...

[0007] The two ends of the winding core are respectively provided with positive electrode tabs and negative electrode tabs;

[0008] The positive current collector includes a positive current collector body, and the positive current collector body is fixed to the positive current tab by multiple positive current solder marks.

[0009] The negative electrode current collector and the negative electrode tab are fixed together by welding multiple negative electrode solder marks;

[0010] The end face area of ​​the core is S0, and the span of the positive electrode solder mark along its length is L. 10 The span of the positive electrode solder mark along its width direction is W. 10 The area of ​​each of the positive electrode solder marks is S. 10 The sum of the area of ​​the plurality of positive electrode solder marks is S. 100 , among which, S 10 =L 10 ·W 10 13.3% ≤ S 100 / S0≤17.7%;

[0011] The area of ​​the negative electrode current collector is S. 20 The span of the negative electrode solder mark along its length is L. 20 The span of the negative electrode solder mark along its width direction is W. 20 The area of ​​each negative electrode solder mark is S. 200 The sum of the area of ​​the multiple negative electrode solder marks is S. 2000 , among which, S 200 =L 20 ·W 20 10% ≤ S 2000 / S 20 ≤20%.

[0012] Based on the above technical solutions, the preferred option is 3.3% ≤ S 10 / S0≤4.4%, 3%≤S 200 / S 20 ≤5%.

[0013] Further preferred, 3.9mm≤L 10 ≤5.1mm, 2.4mm≤W 10 ≤3.2mm.

[0014] Further preferred, 3.5mm≤L 20 ≤5.5mm, 1.6mm≤W 20 ≤3.4mm.

[0015] Based on the above technical solutions, preferably, the positive electrode solder mark is in the shape of a broken line, and the line width of the positive electrode solder mark is W0, wherein 0.2mm≤W0≤0.4mm.

[0016] More preferably, the turning angle of the positive electrode solder mark is A, wherein 10°≤A≤30°.

[0017] Based on the above technical solutions, preferably, the negative electrode solder mark includes a plurality of parallel and spaced negative electrode solder lines, and the negative electrode solder lines are in the shape of zigzag lines;

[0018] The spacing between two adjacent negative electrode bonding wires is W 202 Where 0.6mm≤W 202 ≤1.1mm.

[0019] More preferably, the linewidth of the negative electrode bonding wire is W. 203 The difference between the span of the negative electrode bonding wire along its width direction and the linewidth of the negative electrode bonding wire is W. 201 Where 0.15mm≤W 201 ≤0.35mm, 0.1mm≤W 203 ≤0.3mm, and W 203 <W 201 .

[0020] More preferably, the turning angle of the negative electrode welding wire is C, wherein 70°≤C≤120°.

[0021] Based on the above technical solutions, preferably, the end face radius of the winding core is R0, the radius of the positive electrode disk is R1, and the radius of the negative electrode current collector is R. 20 Where 9.18mm≤R0≤11.18mm, 8.8mm≤R1≤9.4mm, and 8.5mm≤R 20 ≤10.5mm, and 86.4%≤R1 / R0≤92.3%.

[0022] The cylindrical secondary battery of this utility model has the following advantages over the prior art: by limiting the setting area of ​​the positive electrode soldering and the negative electrode soldering, the welding effect of the current collector welding position and the current carrying capacity can be taken into account, thereby effectively improving the overall performance of the battery. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a top view of the positive electrode disk in a cylindrical secondary battery according to the present invention.

[0025] Figure 2 This is a top view of the positive electrode solder joint in a cylindrical secondary battery according to the present invention.

[0026] Figure 3 This is a bottom view of the negative electrode current collector in a cylindrical secondary battery according to this utility model.

[0027] Figure 4 This is a bottom view of the negative electrode welding wire in a cylindrical secondary battery according to this utility model.

[0028] Among them: 1. Positive electrode tab; 2. Negative electrode tab; 3. Positive electrode disk; 301. Positive electrode solder mark; 4. Negative electrode current collector; 401. Negative electrode solder mark; 4011. Negative electrode solder wire. Detailed Implementation

[0029] The technical solutions of this utility model will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0030] The present invention relates to a cylindrical secondary battery, comprising a casing, a core, a positive current collector, and a negative current collector.

[0031] The core is set inside the shell. The core includes a positive electrode material, a negative electrode material and a separator. Positive electrode tab 1 and negative electrode tab 2 are respectively provided at both ends of the core. Positive electrode tab 1 is connected to the positive electrode material and negative electrode tab 2 is connected to the negative electrode material.

[0032] The positive current collector includes a positive current collector 3, which is a disc-shaped structure and is fixed to the positive current collector tab 1 by multiple positive current collector solder marks 301. The negative current collector 4 is fixed to the negative current collector tab 2 by multiple negative current collector solder marks 401. This enables the positive current collector and negative current collector 4 to conduct electricity with the winding core.

[0033] The positive electrode solder mark 301 has a zigzag-shaped structure with rounded corners in the curved areas. Preferably, multiple positive electrode solder marks 301 are arranged in a circular array around the center point of the positive electrode disk 3 to improve the welding strength and stability between the positive electrode disk 3 and the positive electrode tab 1.

[0034] The negative electrode solder mark 401 includes multiple negative electrode solder lines 4011, which are also zigzag-shaped structures with rounded corners in their curved areas. The multiple negative electrode solder lines 4011 are arranged in parallel and at intervals. Similarly, it is preferable to have multiple negative electrode solder marks 401, arranged in a circumferential array around the center point of the negative electrode current collector 4, to improve the welding strength and stability between the negative electrode solder mark 401 and the negative electrode tab 2.

[0035] like Figure 1 and Figure 3 As shown, the end face radius of the core is R0, and the end face area of ​​the core is S0, where S0 = π·R0 2 The radius of the positive electrode disk 3 is R1, and the span of the positive electrode solder mark 301 along its length is L. 10 The span of the positive electrode solder mark 301 along its width direction is W. 10 The area of ​​each positive electrode solder mark 301 is S. 10 S 10 =L 10 ·W 10 The sum of the area of ​​multiple positive electrode solder marks 301 is S 100 The radius of the negative current collector 4 is R. 20 The area of ​​the negative electrode current collector 4 is S. 20 S 20 =π·R 20 2 The span of the negative electrode solder mark 401 along its length is L. 20 The span of the negative electrode solder mark 401 along its width direction is W. 20 The area of ​​each negative electrode solder mark 401 is S. 200 S 200 =L 20 ·W 20 The sum of the area of ​​multiple negative electrode solder marks 401 is S 2000 .

[0036] In some embodiments, 9.18mm ≤ R0 ≤ 11.18mm, 8.8mm ≤ R1 ≤ 9.4mm, and 8.5mm ≤ R 20 ≤10.5mm.

[0037] In some embodiments, 13.3% ≤ S 100 / S0≤17.7%, meaning the sum of the area of ​​multiple positive electrode solder marks 301 is 13.3%, 15.5%, or 17.7% of the core end face area, etc. If S 100If S0 < 13.3%, the sum of the area of ​​multiple positive electrode solder marks 301 is too small, resulting in a smaller effective current-carrying area at the soldering position, increased internal resistance of the battery, concentrated heat generation at the soldering position, excessive rate-controlled temperature rise, and impact on battery performance. Simultaneously, the small sum of the area of ​​multiple positive electrode solder marks 301 also leads to insufficient soldering strength at the soldering position, affecting the connection strength. If S0 < 13.3%, the sum of the area of ​​multiple positive electrode solder marks 301 is too small, resulting in insufficient soldering strength at the soldering position, affecting the connection strength at the soldering position. 100 If / S0 > 17.7%, the combined area of ​​multiple positive electrode solder marks 301 is too large, and the welding position is prone to deviating from the weldable area on the positive electrode disk 3, resulting in some welding lines being invalid or the battery being scrapped. This will also affect the battery performance and the connection strength of the welding position. At the same time, the combined area of ​​multiple positive electrode solder marks 301 being too large will also lead to a longer welding time, which will reduce welding efficiency and increase the manufacturing cost of the battery.

[0038] In some embodiments, 10% ≤ S 2000 / S 20 ≤20%, meaning the sum of the area of ​​multiple negative electrode solder marks 401 is 10%, 15%, or 20% of the area of ​​the negative electrode current collector 4, etc. If S 2000 / S 20 If the area is less than 10%, the combined area of ​​multiple negative electrode solder marks 401 is too small, reducing the effective current-carrying area at the soldering position, weakening the current-carrying capacity, and causing an increase in temperature at the soldering position, thus affecting battery performance. If S 2000 / S 20 If the area of ​​multiple negative electrode solder marks (401) is greater than 20%, the area of ​​the marks will be too large. This will not only fail to optimize the internal resistance of the battery, but will also increase the welding time and reduce the welding efficiency. At the same time, during the welding process, heat will be difficult to dissipate in time, and welding defects such as welding explosions will easily occur, affecting the welding reliability of the welding position.

[0039] In some embodiments, 3.3% ≤ S 10 / S0≤4.4%, meaning the area of ​​each positive electrode solder mark 301 is 3.3%, 4%, or 4.4% of the core end face area, etc. If S 10 If S0 < 3.3%, then the area of ​​each positive electrode solder mark 301 is too small, the effective current-carrying area at the soldering position is reduced, the internal resistance of the battery increases, resulting in concentrated heat generation at the soldering position, excessive rate-controlled temperature rise, and affecting battery performance. Simultaneously, an excessively small area of ​​each positive electrode solder mark 301 also leads to insufficient soldering strength at the soldering position, affecting the connection strength. If S0 < 3.3%, then the effective current-carrying area of ​​each positive electrode solder mark 301 is too small, resulting in insufficient soldering strength at the soldering position, affecting the connection strength at the soldering position. 10If / S0 > 4.4%, the area of ​​each positive electrode solder mark 301 is too large, and the welding position is prone to deviating from the weldable area on the positive electrode disk 3, resulting in some welding lines being invalid or the battery being scrapped. This will also affect the performance of the battery and the connection strength of the welding position. At the same time, if the area of ​​each positive electrode solder mark 301 is too large, it will also lead to a longer welding time, which will reduce welding efficiency and increase the manufacturing cost of the battery.

[0040] In some embodiments, 3% ≤ S 200 / S 20 ≤5%, meaning the area of ​​each negative electrode solder mark 401 is 3%, 4%, or 5% of the area of ​​the negative electrode current collector 4, etc. If S 200 / S 20 If the area is less than 3%, the area of ​​each negative electrode solder mark 401 is too small, reducing the effective current-carrying area at the soldering position, weakening the current-carrying capacity, and causing an increase in temperature at the soldering position, thus affecting battery performance. If S 200 / S 20 If the area of ​​each negative electrode solder mark 401 is greater than 5%, it will not only fail to optimize the internal resistance of the battery, but will also increase the welding time and reduce the welding efficiency. At the same time, during the welding process, heat is difficult to dissipate in time, and welding defects such as welding explosions are prone to occur, affecting the welding reliability of the welding position.

[0041] In some embodiments, 3.9mm≤L 10 ≤5.1mm, meaning the span of the positive electrode solder mark 301 along its length is 3.9mm, 4.5mm, or 5.1mm, etc. If L 10 If the span is less than 3.9mm, the span of the positive electrode solder mark 301 along its length is too small, reducing the effective current-carrying area at the soldering position, weakening the current-carrying capacity, and causing an increase in temperature at the soldering position, thus affecting battery performance. If L 10 If the span is greater than 5.1mm, the positive electrode solder mark 301 will have too large a span along its length, and the welding position will easily exceed the weldable area on the positive electrode disk 3, resulting in battery scrap, reduced welding efficiency, and increased battery manufacturing cost.

[0042] In some embodiments, 2.4mm≤W 10 ≤3.2mm, meaning the span of the positive electrode solder mark 301 along its width direction is 2.4mm, 2.8mm, or 3.2mm, etc. If W 10 If the span is less than 2.4mm, the width of the positive electrode solder mark 301 is too small, reducing the effective current-carrying area at the soldering position and weakening the current-carrying capacity. This leads to an increase in temperature at the soldering position, affecting battery performance. Simultaneously, a small width of the positive electrode solder mark 301 can also cause some solder lines to become excessively concentrated, making them prone to welding defects such as solder bursts due to heat concentration during the soldering process. If W 10If the span of the positive electrode solder mark 301 is greater than 3.2mm, the soldering position is likely to exceed the solderable area on the positive electrode disk 3, resulting in some solder lines becoming invalid. This will not only reduce the battery's overcurrent capacity but also affect the connection strength of the soldering position.

[0043] In some embodiments, 3.5mm≤L 20 ≤5.5mm, meaning the span of the negative electrode solder mark 401 along its length is 3.5mm, 4.5mm, or 5.5mm, etc. If L 20 If the span is less than 3.5mm, the span of the negative electrode solder mark 401 along its length is too small, reducing the effective current-carrying area at the soldering position, weakening the current-carrying capacity, and causing an increase in temperature at the soldering position, thus affecting battery performance. If L 20 If the span is greater than 5.5mm, the span of the negative electrode solder mark 401 along its length is too large. This will not only fail to optimize the internal resistance of the battery, but will also increase the welding time, reduce the welding efficiency, and affect the welding reliability of the welding position.

[0044] In some embodiments, 1.6mm≤W 20 ≤3.4mm, meaning the span of the negative electrode solder mark 401 along its width direction is 1.6mm, 2.5mm, or 3.4mm, etc. If W 20 If the span is less than 1.6mm, the width of the negative electrode solder mark 401 is too small, and the spacing between two adjacent negative electrode solder lines 4011 is too small. During the welding process, the heat is concentrated, which easily leads to welding defects such as burn-through and spalling. If W 20 If the span is greater than 3.4mm, the span of the negative electrode solder mark 401 along its width direction is too large, and the spacing between two adjacent negative electrode solder lines 4011 is too large, which will increase the stroke of the welding equipment, affect the welding efficiency, and reduce the welding capacity.

[0045] In some embodiments, 86.4% ≤ R1 / R0 ≤ 92.3%, meaning the radius of the positive electrode disk 3 is 86.4%, 89%, or 92.3% of the radius of the core end face, etc. If R1 / R0 < 86.4%, the radius of the positive electrode disk 3 is too small, the welding area between the positive electrode disk 3 and the core becomes smaller, the current carrying capacity at the corresponding welding position weakens, the temperature rise increases, and the battery performance is affected. When the core is installed into the casing, the casing opening is usually sealed by mechanical sealing with a grooving method. This method causes axial deformation at the groove position of the casing. If R1 / R0 > 92.3%, the radius of the positive electrode disk 3 is too large, and the deformed casing is prone to contacting the edge of the positive electrode disk 3, leading to an increased risk of short circuit.

[0046] like Figure 2 As shown, the line width of the positive electrode solder mark 301 is W0, and the turning angle of the positive electrode solder mark 301 is A.

[0047] In some embodiments, 0.2mm ≤ W0 ≤ 0.4mm, meaning the linewidth of the positive electrode solder mark 301 is 0.2mm, 0.3mm, or 0.4mm, etc. If W0 < 0.2mm, the linewidth of the positive electrode solder mark 301 is too small, weakening the current-carrying capacity at the soldering position, increasing the internal resistance of the battery, and raising the overcurrent temperature rise at the soldering position, which will affect the battery performance. If W0 > 0.4mm, the linewidth of the positive electrode solder mark 301 is too large, resulting in some solder lines being too close together. During the soldering process, welding defects such as solder bursts are easily caused by heat concentration, affecting the connection strength at the soldering position.

[0048] In some embodiments, 10°≤A≤30°, meaning the turning angle of the positive electrode solder mark 301 is 10°, 20°, or 30°, etc. If A<10°, the turning angle of the positive electrode solder mark 301 is too small, resulting in some solder lines being too close together. During the soldering process, this can easily lead to soldering defects such as solder bursts due to heat concentration, affecting the connection strength and current carrying capacity of the soldered position. If A>30°, the turning angle of the positive electrode solder mark 301 is too large. Within a certain span, the length of the solder line of the positive electrode solder mark 301 is shortened, leading to a weakened current carrying capacity and an increased temperature rise at the soldered position, thus affecting the battery performance.

[0049] like Figure 4 As shown, the difference between the span of the negative electrode bonding wire 4011 along its width direction and the linewidth of the negative electrode bonding wire 4011 is W. 201 The spacing between two adjacent negative electrode bonding wires 4011 is W. 202 The linewidth of the negative electrode bonding wire 4011 is W. 203 The turning angle of the negative electrode bonding wire 4011 is C.

[0050] In some embodiments, 0.15mm≤W 201 ≤0.35mm, meaning the difference between the span of the negative electrode bonding wire 4011 along its width direction and the line width of the negative electrode bonding wire 4011 is 0.15mm, 0.25mm, or 0.35mm, etc. If W 201 If the distance is less than 0.15mm, the distance between two adjacent negative electrode welding wires 4011 is too close. During the welding process, welding defects such as welding bursts are prone to occur due to heat concentration, affecting the connection strength and current carrying capacity of the welding position. If W 201 If the distance is greater than 0.35mm, the distance between two adjacent negative electrode welding wires 4011 will be too far, which will increase the stroke of the welding equipment, affect the welding efficiency, and reduce the welding capacity.

[0051] In some embodiments, 0.6mm≤W 202 ≤1.1mm, meaning the spacing between two adjacent negative electrode bonding wires 4011 is 0.6mm, 0.85mm, or 1.1mm, etc. If W 202If the distance is less than 0.6mm, the distance between two adjacent negative electrode welding wires 4011 is too close. During the welding process, welding defects such as welding bursts are prone to occur due to heat concentration, affecting the connection strength and current carrying capacity of the welding position. If W 202 If the distance is greater than 1.1mm, the distance between two adjacent negative electrode welding wires 4011 will be too far, which will increase the stroke of the welding equipment, affect the welding efficiency, and reduce the welding capacity.

[0052] In some embodiments, 0.1mm≤W 203 ≤0.3mm, and W 203 <W 201 That is, the linewidth of the negative electrode bonding wire 4011 is 0.1mm, 0.2mm, or 0.3mm, etc., and is less than the difference between the span of the negative electrode bonding wire 4011 along its width direction and the linewidth of the negative electrode bonding wire 4011. If W 203 If the line width is less than 0.1mm, the negative electrode bonding wire 4011 is too small, weakening the current-carrying capacity at the bonding location, increasing the battery's internal resistance, and raising the overcurrent temperature rise at the bonding location, which will affect the battery's performance. If W 203 If the width is greater than 0.3mm, the line width of the negative electrode bonding wire 4011 is too large, which does not have a better effect on optimizing the internal resistance of the battery. However, the increase in the welding area will reduce the welding reliability of the welding position.

[0053] In some embodiments, 70°≤C≤120°, meaning the turning angle of the negative electrode bonding wire 4011 is 70°, 95°, or 120°, etc. If C<70°, the turning angle of the negative electrode bonding wire 4011 is too small, resulting in some bonding wires being too close together. During the welding process, welding defects such as welding bursts are easily caused by heat concentration, affecting the connection strength and current carrying capacity at the welding position. If C>120°, the turning angle of the negative electrode bonding wire 4011 is too large. Within a certain span, the length of the negative electrode bonding wire 4011 is shortened, leading to a weakened current carrying capacity and an increased temperature rise at the welding position, affecting the battery performance.

[0054] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A cylindrical secondary battery, characterized in that: Includes a winding core, a positive current collector, and a negative current collector (4), among which, The two ends of the winding core are respectively provided with a positive electrode tab (1) and a negative electrode tab (2); The positive current collector includes a positive current collector body (3), and the positive current collector body (3) and the positive current collector tab (1) are welded and fixed together by a plurality of positive current collector solder marks (301); The negative electrode current collector (4) and the negative electrode tab (2) are fixed together by welding through multiple negative electrode solder marks (401); The end face area of ​​the core is S0, and the span of the positive electrode solder mark (301) along its length is L. 10 The span of the positive electrode solder mark (301) along its width direction is W. 10 The area of ​​each of the positive electrode solder marks (301) is S. 10 The sum of the area of ​​the plurality of positive electrode solder marks (301) is S. 100 , among which, S 10 =L 10 ·W 10 13.3% ≤ S 100 / S0≤17.7%; The area of ​​the negative current collector (4) is S 20 The negative electrode solder mark (401) has a span of L along its length direction. 20 The span of the negative electrode solder mark (401) along its width direction is W. 20 The area of ​​each negative electrode solder mark (401) is S. 200 The sum of the area of ​​the plurality of negative electrode solder marks (401) is S. 2000 , among which, S 200 =L 20 ·W 20 10% ≤ S 2000 / S 20 ≤20%.

2. The cylindrical secondary battery as described in claim 1, characterized in that: 3.3%≤S 10 / S0≤4.4%,3%≤S 200 / S 20 ≤5%。 3. A cylindrical secondary battery as described in claim 2, characterized in that: 3.9mm≤L 10 ≤5.1mm,2.4mm≤W 10 ≤3.2mm。 4. A cylindrical secondary battery as described in claim 2, characterized in that: 3.5mm≤L 20 ≤5.5mm,1.6mm≤W 20 ≤3.4mm。 5. A cylindrical secondary battery as described in claim 1, characterized in that: The positive electrode solder mark (301) is in the shape of a broken line, and the line width of the positive electrode solder mark (301) is W0, wherein 0.2mm≤W0≤0.4mm.

6. A cylindrical secondary battery as described in claim 5, characterized in that: The turning angle of the positive electrode solder mark (301) is A, where 10°≤A≤30°.

7. A cylindrical secondary battery as described in claim 1, characterized in that: The negative electrode solder mark (401) includes a plurality of parallel and spaced negative electrode solder lines (4011), and the negative electrode solder lines (4011) are in the shape of zigzag lines; The spacing between two adjacent negative electrode bonding wires (4011) is W. 202 Where 0.6mm≤W 202 ≤1.1mm.

8. A cylindrical secondary battery as described in claim 7, characterized in that: The linewidth of the negative electrode bonding wire (4011) is W. 203 The difference between the span of the negative electrode bonding wire (4011) along its width direction and the linewidth of the negative electrode bonding wire (4011) is W. 201 Where 0.15mm≤W 201 ≤0.35mm, 0.1mm≤W 203 ≤0.3mm, and W 203 <W 201 .

9. A cylindrical secondary battery as described in claim 8, characterized in that: The turning angle of the negative electrode bonding wire (4011) is C, where 70°≤C≤120°.

10. A cylindrical secondary battery as described in any one of claims 1-9, characterized in that: The end face radius of the winding core is R0, the radius of the positive electrode disk (3) is R1, and the radius of the negative electrode current collector disk (4) is R. 20 Where 9.18mm≤R0≤11.18mm, 8.8mm≤R1≤9.4mm, and 8.5mm≤R 20 ≤10.5mm, and 86.4%≤R1 / R0≤92.3%.

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