A soldering structure and a cylindrical lithium-ion battery

Abstract

This utility model relates to the field of lithium battery technology, and proposes a soldering structure and a cylindrical lithium-ion battery. The soldering structure includes multiple parallel and spaced solder lines, and the solder lines are wavy in shape. The width W1 of the soldering structure is 1.6-3.4 mm; the minimum distance W10 between two adjacent solder lines is 0.6-1.1 mm. By controlling the reasonable size of the soldering, problems such as welding explosions and discoloration of solder lines caused by heat concentration due to excessively small soldering can be avoided. At the same time, excessively large soldering can prevent the increase in laser travel, the reduction in welding efficiency and production capacity, and the decrease in welding reliability caused by the expansion of the solder line area, thereby effectively improving welding quality and efficiency.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery technology, and in particular to a soldering structure and a cylindrical lithium-ion battery. Background Technology

[0002] A cylindrical battery is a type of battery composed of components such as a positive electrode, a negative electrode, a separator, an electrolyte, and a casing. Its overall shape is cylindrical. Its structure typically includes components such as a casing, a cap, a positive electrode, a negative electrode, a separator, an electrolyte, a PTC element, gaskets, and a safety valve. These components work together to ensure that the battery can be charged and discharged normally and to provide protection in abnormal conditions.

[0003] A positive electrode current collector, a negative electrode current collector, and a cylindrical battery with all tabs are disclosed in CN220895786U. The surface of the negative electrode current collector is provided with a connecting isolation groove and a welding isolation groove. The welding isolation groove is connected to the connecting isolation groove. Two connecting isolation grooves are provided, and a buffer sheet is formed between the two connecting isolation grooves. The welding isolation groove surrounds and forms a first welding sheet. The first welding sheet is connected to the body of the negative electrode current collector through the buffer sheet.

[0004] The current setting of the negative electrode solder mark position is unreasonable. Both excessively large and excessively small solder marks will affect the welding. If the solder mark is too small, the heat concentration will cause welding explosions and discoloration of the solder line. If the solder mark is too large, it will increase the laser travel, reduce welding efficiency and production capacity, and the increased solder line area will reduce welding reliability, thereby reducing welding quality and efficiency. Utility Model Content

[0005] In view of this, this utility model proposes a soldering structure and a cylindrical lithium-ion battery. By controlling the reasonable size of the soldering, it can avoid problems such as soldering explosions and discoloration of the solder line caused by heat concentration due to the soldering being too small. At the same time, it can prevent the increase in laser travel, reduction in welding efficiency and production capacity, and decrease in welding reliability caused by the expansion of the solder line area due to the soldering being too large, thereby effectively improving welding quality and efficiency.

[0006] The technical solution of this utility model is implemented as follows: In the first aspect, this utility model provides a solder stamp structure, which includes multiple parallel and spaced solder lines, the shape of which is wavy, wherein the width W1 of the solder stamp structure is 1.6-3.4mm; and the minimum distance W10 between two adjacent solder lines is 0.6-1.1mm.

[0007] Based on the above technical solutions, preferably, the welding wire has multiple concave portions and convex portions, the multiple concave portions and convex portions are arranged alternately and continuously, and adjacent concave portions and convex portions are centrally rotate symmetrical to form a wavy welding wire. The minimum distance between the outer convex tip of the concave portion and the inner convex tip of the convex portion is W30, where W30 = 0.15-0.35 mm.

[0008] Based on the above technical solutions, preferably, the width of the welding wire is equal to the width of the concave portion and the convex portion, the width W20 of the welding wire is 0.1-0.3mm, and the minimum distance W30 between the outer convex tip of the concave portion and the inner convex tip of the convex portion is greater than the width W20 of the welding wire.

[0009] Based on the above technical solutions, preferably, the protrusion angle B of the concave portion and the convex portion is 70-120°, and preferably, the protrusion angles are the same.

[0010] Based on the above technical solutions, preferably, the length L1 of the solder mark structure is 3.5-5.5mm.

[0011] Secondly, this utility model also provides a cylindrical lithium-ion battery, including multiple soldered structures and a negative electrode current collector, wherein the multiple soldered structures are all disposed on the surface of the negative electrode current collector and are distributed around its axis; the ratio of the area S0 of the negative electrode current collector to the area S10 of a single soldered structure is in the range of S10 / S0=3%-5%.

[0012] Based on the above technical solutions, preferably, the ratio of the area S0 of the negative electrode current collector to the sum of all soldered structures S100 is in the range of S100 / S0 = 10-20%.

[0013] Based on the above technical solutions, preferably, a boss is provided at the center of the negative electrode current collector, and the radius R1 of the boss is 2.0-4.0mm.

[0014] Based on the above technical solutions, preferably, the minimum distance L0 between the soldering structure and the outer edge of the negative electrode current collector is 0.5-1.5mm; the minimum distance L2 between the soldering structure and the boss is 0.5-1.5mm; the radius R0 of the negative electrode current collector is 8.5-10.5mm; and L0+L1+L2+R1=R0.

[0015] Based on the above technical solutions, preferably, the number of the soldering structures is four, and the four soldering structures are symmetrically distributed in a cross shape with the center point of the negative electrode current collector.

[0016] The current collector soldering structure and cylindrical secondary battery of this invention have the following advantages over the prior art:

[0017] (1) By controlling the minimum distance between two adjacent welding lines within a reasonable range, the appropriate spacing between welding lines is ensured, avoiding the heat concentration caused by too small a distance leading to welding explosions and changes in the color of the welding lines, and preventing the welding efficiency from decreasing due to too large a distance, thereby improving the welding efficiency and quality of the battery.

[0018] (2) The concave and convex structures of the wavy welding wire increase the contact area between the welding wire and the material being welded, significantly improving the welding bond strength; at the same time, controlling the wavy protrusion parameters helps to control the welding heat distribution and improve the welding quality.

[0019] (3) By controlling the ratio of the solder stamp area to the current collector area, the solder stamp structure has sufficient current flow area, reducing the current density and reducing the performance degradation of the heat-affected zone. At the same time, the uniformity of current distribution is optimized at the global level to avoid the risk of thermal runaway caused by excessive concentration in the solder stamp area, and at the same time, the welding yield is improved.

[0020] (4) By controlling the minimum distance between the solder mark structure and the edge of the boss and the current collector, the solder line is prevented from overflowing into the non-target area during the welding process, thus ensuring the integrity of the effective welding area and the current conduction path. Attached Figure Description

[0021] 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.

[0022] Figure 1 This is a schematic diagram of the solder joint structure of this utility model;

[0023] Figure 2 This is a schematic diagram of the length and width markings of the soldering structure of this utility model;

[0024] Figure 3 This is a schematic diagram of the internal parameter markings of the solder stamp structure of this utility model;

[0025] Figure 4 This is a schematic diagram of the negative electrode current collector structure of this utility model;

[0026] Figure 5 This is a schematic diagram of the negative electrode current collector structure of this utility model. Detailed Implementation

[0027] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. 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 of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0028] Firstly, such as Figure 1-3 As shown, this utility model provides a solder stamp structure 1, which includes multiple parallel and spaced solder lines 11. The solder lines 11 are wavy in shape, and the minimum distance W10 between two adjacent solder lines 11 is 0.6-1.1 mm.

[0029] It should be noted that laser welding is usually performed line by line. When the minimum distance W10 between adjacent weld lines is too large, the laser needs to move a longer distance to complete the welding of each weld line. As the distance increases, the laser needs to spend more time on the travel distance, resulting in a decrease in the number of weld lines that can be completed per unit time, thus significantly reducing welding efficiency. Furthermore, the weld line area will relatively increase with the increase of the minimum distance W10 between adjacent weld lines. When the weld line spacing is too large, the heat-affected zones between weld lines are relatively independent, which may lead to insufficient welding fusion in some areas, resulting in welding defects and reducing the reliability of the welding.

[0030] When the minimum distance W10 between adjacent solder wires is too small, the wires are very close together. During the soldering process, the heat generated by the solder wires will be superimposed. Due to the limited space between the wires, the heat is difficult to dissipate quickly, leading to localized heat concentration. Furthermore, this heat concentration will cause the surrounding material to heat up and expand rapidly. When the expansion is restricted by the surrounding material, it may generate enormous pressure, causing a blowout during the soldering process. This not only affects the appearance quality of the soldered structure but may also damage the bond between the solder wire and the substrate, reducing the soldering strength. Moreover, excessively high temperatures can cause oxidation or other chemical reactions in the solder wire material, resulting in a change in the solder wire color. This not only affects the product's aesthetics but also alters the properties of the solder wire material, such as reduced strength and decreased conductivity, thereby affecting the overall performance and lifespan of the soldered structure.

[0031] In this embodiment, by controlling the minimum distance between two adjacent welding lines 11 within the range of 0.6-1.1mm, a suitable spacing between welding lines is ensured, avoiding the occurrence of welding explosions and color changes due to excessively small distances caused by heat concentration, while also preventing a decrease in welding efficiency due to excessively large distances, thereby improving the welding efficiency and quality of the battery.

[0032] Specifically, in this embodiment, the minimum distance W10 between two adjacent welding lines 11 is 0.82 mm.

[0033] In this embodiment, the bonding wire 11 has multiple concave portions 101 and convex portions 102. The multiple concave portions 101 and convex portions 102 are arranged alternately and continuously, and adjacent concave portions 101 and convex portions 102 are centrally rotationally symmetrical to form a wavy bonding wire 11. The minimum distance between the outer protruding tip of the concave portion 101 and the inner protruding tip of the convex portion 102 is W30, where W30 = 0.15-0.35 mm.

[0034] It should be noted that the concave portion 101 and convex portion 102 structure of the wavy welding wire 11, compared with the straight welding wire, greatly increases the contact area between the welding wire and the welded material. During the welding process, more contact points enable the welding wire and the welded material to form a stronger bond, thereby significantly improving the welding bond strength. Furthermore, the W30 within a reasonable range of 0.15-0.35mm is conducive to controlling the heat distribution during welding. The appropriate spacing allows the welding heat to be distributed relatively evenly around the welding wire, avoiding welding quality problems caused by excessively high or low local heat.

[0035] Specifically, in this embodiment, the minimum distance W30 between the outer protruding tip of the concave portion 101 and the inner protruding tip of the convex portion 102 is 0.26 mm.

[0036] In this embodiment, the width of the bonding wire 11 is equal to the width of the concave portion 101 and the convex portion 102. The width W20 of the bonding wire 11 is 0.1-0.3 mm, and the minimum distance W30 between the outer protruding tip of the concave portion 101 and the inner protruding tip of the convex portion 102 is greater than the width W20 of the bonding wire 11.

[0037] It should be noted that when the width W20 of the bonding wire 11 is too large, the overall area of ​​the bonding wire will increase accordingly. During the welding process, the increased area of ​​the bonding wire may lead to uneven distribution of welding heat input, resulting in insufficient welding in some areas and welding defects such as incomplete fusion and cold solder joints. Moreover, a larger bonding wire area will increase the interface between the bonding wire and the welded material, making it more prone to stress concentration when subjected to external forces or thermal stress. This can cause the bonding wire to detach from the welded material, reducing the reliability of the welding and affecting the stability and durability of the soldered structure in actual use. Furthermore, although increasing the width of the bonding wire may affect the battery internal resistance to some extent, once the width exceeds a certain range, further increasing the width does not have a significant effect on further optimizing the battery internal resistance. However, the increase in the area of ​​the bonding wire will reduce the reliability of the welding.

[0038] When the width W20 of the bonding wire 11 is too small, the current-carrying area of ​​the bonding wire will be reduced. According to the principle of current transmission, the smaller the current-carrying area, the greater the resistance when the current passes through, and the weaker the current-carrying capacity. The weakened current-carrying capacity will generate more heat at the bonding wire, resulting in an increase in the temperature at the bonding wire and affecting the performance of the battery.

[0039] In this embodiment, the width W20 of the bonding wire 11 is within a suitable range of 0.1-0.3mm. This avoids the reduced current flow area and weakened current flow capacity caused by excessively small width, which would lead to an increase in the temperature of the bonding wire and affect the battery performance. It also improves the reliability of the welding process.

[0040] Specifically, in this embodiment, the width W20 of the bonding wire 11 is 0.2mm.

[0041] In this embodiment, the protrusion angle B of the concave portion 101 and the convex portion 102 is 70-120°, and preferably the protrusion angles are the same.

[0042] It should be noted that when the protrusion angle B is too small, the relative positional relationship between the concave part 101 and the convex part 102 in a single welding wire results in a very close distance between the welding wires. During the welding process, heat will accumulate rapidly between these closely spaced welding wires, leading to heat concentration. The high-temperature environment will have an adverse effect on the welding wire material, easily causing welding spalling and reducing welding strength and quality. When the protrusion angle B is too large, the welding wire needs to meet a certain weldable length to ensure that the weldable area of ​​the welding wire is sufficient. However, due to the excessive angle, the straight-line distance between the beginning and end of the welding wire becomes longer within a certain welding wire length. This will cause the welding wire to extend beyond the pad surface, resulting in partial welding wire failure, loss of current carrying capacity, weakened current carrying capacity at the welding wire, increased current temperature rise, and impact on battery performance.

[0043] In this embodiment, the protrusion angle B of the concave portion 101 and the convex portion 102 is controlled within the range of 70-120°. This ensures a suitable spacing between the welding wires, avoiding excessively small distances that could lead to heat concentration causing welding spatter and color changes in the welding wires. It also ensures the current carrying capacity, thereby improving the welding quality.

[0044] Specifically, in this embodiment, the protrusion angle B = 95°.

[0045] In this embodiment, the length L1 of the solder mark structure 1 is 3.5-5.5mm.

[0046] It should be noted that if the length L1 of the solder mark structure 1 is too small, the current carrying capacity of the solder line will be weakened, the local heat generation in the solder mark area will be large during current carrying, the temperature at the solder joint will rise, the internal resistance of the battery will increase, and the battery performance will be affected. If the length L1 of the solder mark structure 1 is too large, the solder line will be too long. Although it will not have a significant effect on improving the internal resistance of the battery, it will increase the risk of soldering failure rate and reduce the soldering reliability.

[0047] In this embodiment, the length L1 of the soldering structure 1 is controlled within the range of 3.5-5.5mm, which can ensure that the soldering wire has sufficient current carrying capacity and maintain good battery performance, while reducing the soldering defect rate and improving soldering reliability.

[0048] Specifically, in this embodiment, the length L1 of the solder mark structure 1 is 4.5mm.

[0049] In this embodiment, the width W1 of the solder mark structure 1 is 1.6-3.4mm.

[0050] It should be noted that the solder mark structure 1 in this embodiment has three parallel solder lines 11. If the width W1 of the solder mark structure 1 is too small, the three solder lines 11 will be too concentrated, resulting in more heat accumulation during welding, which may easily lead to welding defects such as burn-through and explosion, thus increasing the welding defect rate. If the width W1 of the solder mark structure 1 is too large, the distance between the three solder lines will be too far, resulting in a larger travel distance during laser welding, which will reduce welding efficiency and thus reduce production capacity.

[0051] In this embodiment, the width W1 of the solder mark structure 1 is controlled within the range of 1.6-3.4mm, which can avoid poor welding caused by excessively concentrated solder lines, ensure welding quality, and at the same time prevent excessively large solder line spacing from reducing welding efficiency.

[0052] Specifically, in this embodiment, the width W1 of the solder mark structure 1 is 2.5mm.

[0053] Secondly, such as Figure 4-5 As shown, this utility model also provides a cylindrical lithium-ion battery, including multiple solder structures 1 and a negative electrode current collector 2, wherein the multiple solder structures 1 are all disposed on the surface of the negative electrode current collector 2 and are distributed around its axis; the ratio of the area S0 of the negative electrode current collector 2 to the area S10 of a single solder structure 1 is in the range of S10 / S0=3%-5%.

[0054] It should be noted that when the ratio of the area S0 of the negative electrode current collector 2 to the area S10 of a single solder structure 1 is too small, that is, when S10 / S0 is too small, it means that the area of ​​the solder structure is relatively small, and the current-carrying area is also reduced. The weakened current-carrying capacity will cause the current density to increase when the solder wire carries the same current, so more heat will be generated at the solder wire, which will seriously affect the performance of the battery. When S10 / S0 is too large, the area of ​​the solder structure is relatively large. Although it has no significant effect on improving the internal resistance of the battery, it will increase the risk of welding failure rate and reduce welding reliability.

[0055] In this embodiment, the ratio of the area S0 of the negative electrode current collector 2 to the area S10 of a single solder structure 1 is controlled within the range of 3%-5%. This ensures that the solder structure has sufficient current carrying capacity and maintains good battery performance, while avoiding the problem of reduced welding reliability due to excessive solder area. This is conducive to achieving stable and efficient performance of cylindrical lithium-ion batteries.

[0056] Specifically, in this embodiment, the overall area S0 of the negative electrode current collector 2 is calculated to be S0 = 283.4 mm with a radius R0 = 9.5 mm. 2 The area of ​​a single solder mark structure 1, calculated with length L1 = 4.5 mm and width W1 = 2.5 mm, is S10 = 11.25 mm². 2 The ratio of the area S0 of the negative current collector 2 to the area S10 of a single solder structure 1 is S10 / S0 = 3.96%.

[0057] In this embodiment, the ratio of the area S0 of the negative current collector 2 to the sum of all solder structures 1 S100 is in the range of S100 / S0 = 10-20%.

[0058] It should be noted that when the ratio of the area S0 of the negative electrode current collector 2 to the sum S100 of all solder structures 1 is too small, i.e., when S100 / S0 is too small, it means that the area of ​​the solder structure is relatively small, and the current-carrying area is also reduced. The weakened current-carrying capacity will cause the current density to increase when the solder wire carries the same current, so more heat will be generated at the solder wire, which will seriously affect the performance of the battery. When S100 / S0 is too large, the area of ​​the solder structure is relatively large. Although it has no significant effect on improving the internal resistance of the battery, it will increase the risk of welding failure rate and reduce welding reliability.

[0059] In this embodiment, the ratio of the area S0 of the negative electrode current collector 2 to the sum of the areas S100 of all solder structures is controlled within the range of 10%-20%. This ensures that the solder structure has sufficient current carrying capacity while avoiding the problem of reduced welding reliability and heat concentration between solder lines due to excessively large solder area, thus achieving stable and efficient performance of cylindrical lithium-ion batteries.

[0060] Specifically, in this embodiment, the sum of the areas of all solder marks 1 is S100 = S10. 4=45mm 2 The ratio of the area S0 of the negative electrode current collector 2 to the sum of all solder structures 1 S100 is S100 / S0 = 15.9%.

[0061] In this embodiment, a boss 3 is provided at the center of the negative electrode current collector 2, and the radius R1 of the boss 3 is 2.0-4.0mm.

[0062] It should be noted that when the radius R1 of the protrusion 3 is too small, the corresponding weldable area S1 will also be small. When the protrusion of the negative electrode current collector is penetrated and welded to the bottom of the casing, the effective welding area is insufficient. Insufficient welding area will lead to an increase in current density during welding, resulting in a higher temperature rise at the weld and affecting the battery performance. When the radius R1 of the protrusion 3 is too large, the flatness of S1 is difficult to control. When the protrusion 3 is penetrated and welded to the bottom of the casing, it cannot be guaranteed that the protrusion 3 is completely flat with the casing. During welding, incomplete welds and explosions are likely to occur, which will affect the battery performance.

[0063] In this embodiment, the radius R1 of the boss 3 is controlled within the range of 2.0-4.0mm, which can ensure that the weldable area meets the welding requirements, avoid excessive temperature rise at the welding point affecting battery performance, and at the same time, make it easy to control the flatness, ensuring that the boss and the shell can fit well during welding, reducing the occurrence of welding defects such as cold solder joints and explosions, and achieving stable and efficient performance of cylindrical lithium-ion batteries.

[0064] Specifically, in this embodiment, the radius R1 of the boss 3 is 3mm.

[0065] In this embodiment, the minimum distance L0 between the solder mark structure 1 and the outer edge of the negative electrode current collector 2 is 0.5-1.5mm; the minimum distance L2 between the solder mark structure 1 and the boss 3 is 0.5-1.5mm; the radius R0 of the negative electrode current collector 2 is 8.5-10.5mm; and L0+L1+L2+R1=R0.

[0066] It should be noted that when the minimum distance L2 between the solder mark structure 1 and the boss 3 is too small, the welding line 11 is closer to the middle boss 3. Since the boss 3 is the welding surface used to weld with the steel shell, if the distance L2 is too small, the welding line is easy to weld onto the boss 3, resulting in a reduction in the weldable area between the boss 3 and the bottom of the shell. The overcurrent temperature rise at the weld point where the bottom of the shell is penetrated increases, affecting the performance of the battery. When the minimum distance L2 between the solder mark structure 1 and the boss 3 is too large, the welding line 11 is easy to weld onto the edge of the negative electrode current collector 2, resulting in a reduction in the effective area of ​​the welding line 11. The overcurrent temperature rise at the welding line increases, affecting the performance of the battery. In addition, the minimum distance L0 between the solder mark structure 1 and the outer edge of the negative electrode current collector 2 is controlled in the opposite way to L2.

[0067] In this embodiment, the minimum distance L2 between the soldering structure 1 and the boss 3, and the minimum distance L0 between the soldering structure 1 and the outer edge of the negative electrode current collector 2 are controlled within the range of 0.5-1.5mm. This can avoid problems such as the soldering wire being soldered to the boss, resulting in a reduction of the solderable area, and the soldering wire being close to the edge, causing the effective area to become smaller. This ensures that the soldering wire has sufficient effective area and a suitable layout, reduces overcurrent temperature rise, maintains good battery performance, and improves battery stability and reliability.

[0068] Specifically, in this embodiment, the minimum distance L0 between the solder mark structure 1 and the outer edge of the negative electrode current collector 2 is 1mm, and the minimum distance L2 between the solder mark structure 1 and the boss 3 is 1mm.

[0069] In this embodiment, there are four solder mark structures 1, which are arranged in a cross-shaped symmetrical distribution with respect to the center point of the negative electrode current collector 2.

[0070] It should be noted that the four solder structures 1 are arranged in a cross-shaped symmetrical distribution with the center point of the negative current collector 2, so that the current can be distributed more evenly to each solder structure 1; the current carried by each solder structure is relatively balanced, avoiding the situation of excessive or insufficient local current; and the cross-shaped symmetrical distribution of the negative current collector 2 can enhance the overall strength and stability of the negative current collector 2.

[0071] 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 solder stamp structure, characterized in that, The solder mark structure (1) includes multiple parallel and spaced solder lines (11), the shape of which is wavy. The width W1 of the solder mark structure (1) is 1.6-3.4 mm, and the minimum distance W10 between two adjacent solder lines (11) is 0.6-1.1 mm.

2. The solder print structure of claim 1, wherein: The welding line (11) has multiple concave portions (101) and convex portions (102). The multiple concave portions (101) and convex portions (102) are arranged alternately and continuously. Adjacent concave portions (101) and convex portions (102) are centrally rotate symmetrical to form a wavy welding line (11). The minimum distance between the outer protruding tip of the concave portion (101) and the inner protruding tip of the convex portion (102) is W30, where W30 = 0.15-0.35 mm.

3. The solder print structure of claim 2, wherein: The width of the welding line (11) is equal to the width of the concave portion (101) and the convex portion (102). The width W20 of the welding line (11) is 0.1-0.3 mm, and the minimum distance W30 between the outer protruding top of the concave portion (101) and the inner protruding top of the convex portion (102) is greater than the width W20 of the welding line (11).

4. The solder print structure of claim 2, wherein: The protrusion angle B between the concave portion (101) and the convex portion (102) is 70-120°.

5. The solder print structure of claim 1, wherein: The length L1 of the solder mark structure (1) is 3.5-5.5 mm.

6. A cylindrical lithium-ion battery, characterized by: Includes the solder pattern structure (1) and negative electrode current collector (2) as described in any one of claims 1-5, wherein multiple solder patterns (1) are disposed on the surface of the negative electrode current collector (2) and are distributed around its axis; the ratio of the area S0 of the negative electrode current collector (2) to the area S10 of a single solder pattern structure (1) is in the range of S10 / S0 = 3%-5%.

7. The cylindrical lithium-ion battery of claim 6, wherein: The ratio of the area S0 of the negative current collector (2) to the sum S100 of all solder structures (1) is in the range of S100 / S0 = 10-20%.

8. The cylindrical lithium-ion battery of claim 6, wherein: A boss (3) is provided at the center of the negative electrode current collector (2), and the radius R1 of the boss (3) is 2.0-4.0mm.

9. The cylindrical lithium-ion battery of claim 8, wherein: The minimum distance L0 between the soldering structure (1) and the outer edge of the negative electrode current collector (2) is 0.5-1.5mm; the minimum distance L2 between the soldering structure (1) and the boss (3) is 0.5-1.5mm; and the radius R0 of the negative electrode current collector (2) is 8.5-10.5mm.

10. The cylindrical lithium-ion battery as described in claim 6, characterized in that: The number of the soldering structures (1) is four, and the four soldering structures (1) are symmetrically distributed in a cross shape with the center point of the negative current collector (2).

Images