A cylindrical battery current collector disc welding method

Abstract

This invention discloses a welding method for current collectors in cylindrical batteries, relating to the field of new energy battery technology. The welding method involves: optimizing welding parameters based on a genetic algorithm to find the optimal combination of welding parameters, and then performing welding using the current combination of welding parameters; planning and setting the path during the welding process based on a path planning algorithm, allowing the current collector to move along a predetermined path during welding; forming a core by winding the positive and negative electrodes and the separator, with the separator separating the positive and negative electrodes to prevent short circuits; an upper tab is provided at the upper end of the core, and a lower tab is provided at the lower end of the core, which are then welded to the upper and lower current collectors. This invention effectively increases the current-carrying area after differentiation; it can still ensure a large effective current-carrying area while avoiding the inner and outer sides; and it can find the optimal combination of welding parameters for welding and find the best welding path for movement, bringing better application prospects.

Description

Technical Field

[0001] This invention relates to the field of new energy battery technology, specifically to a welding method for a cylindrical battery current collector. Background Technology

[0002] To improve rate performance, the large cylindrical battery adopts a full tab design, with the tabs and current collector tightly connected by continuous laser welding. There are two common welding methods: one is pulse welding, where the welding trajectory consists of multiple continuous points. This welding method has a large heat-affected zone and is prone to burning the separator, leading to short circuits. Therefore, the tabs need to be flattened and thickened to achieve a relatively stable welding effect. Currently, the flattening process of all tab batteries has been gradually replaced by the stacking process, so pulse welding has also been gradually replaced. The other method is continuous welding, where the welding trajectory is mostly a straight line radiating outward from the center of the circular current collector, which is transformed by software into a spiral or sine line. However, this welding method has a limited effective welding area on the circular current collector and cannot fully utilize the weldable area of ​​the current collector. It also cannot achieve a significant breakthrough in reducing the internal resistance of the battery. At the same time, the welding density of the inner ring electrode is higher than that of the outer ring electrode, resulting in a large difference in the electron transmission distance between the inner and outer ring electrodes, which causes uneven current distribution between the inner and outer ring electrodes and deteriorates the performance of the outer ring electrode. To address this, we propose a welding method for the current collector of cylindrical batteries. Summary of the Invention

[0003] To solve the above-mentioned technical problems, a welding method for cylindrical battery current collectors is provided, and this technical solution solves the above problems.

[0004] To achieve the above objectives, the technical solution adopted by this invention is: a welding method for a cylindrical battery current collector, wherein the welding method is as follows:

[0005] The welding parameters are optimized based on the genetic algorithm to find the optimal combination of welding parameters, and the welding process is carried out using the current combination of welding parameters.

[0006] Based on the path planning algorithm, the path in the welding process is planned and set so that the manifold moves according to the predetermined path during welding.

[0007] The positive and negative electrode plates and the separator are wound together to form a core, and the separator separates the positive and negative electrodes to prevent short circuits.

[0008] The upper end of the core is provided with an upper electrode lug, and the lower end of the core is provided with a lower electrode lug. The upper and lower electrode lugs are welded to the upper and lower current collectors.

[0009] The distribution of the wound cross-section electrode sheet and the electrode lug is an Archimedean spiral, and the welding trajectory is an Archimedean spiral, which is then transformed into a sine curve. The spiral spacing when drawing the Archimedean spiral is a multiple of the electrode lug distribution spacing to ensure that after welding, each area of ​​the electrode lug has a similar weld bead to connect the electrode lug to the current collector.

[0010] When the waveform is transformed into a sine wave, the amplitude is set to be less than the pitch of the Archimedean spiral, and the period is set based on the fact that the inner lines do not intersect.

[0011] Holes are pre-drilled on the collector plate to allow electrolyte to enter the core. The power and time waveform of the welding are precisely set to the light-emitting and non-light-emitting times of each segment, so that the actual light-emitting power is zero at the hole position, and the welding of the collector plate is carried out.

[0012] Preferably, the winding process involves inspecting the positive and negative electrode sheets and the separator raw materials, precisely cutting the positive and negative electrode sheets to predetermined dimensions, and cutting the separator to the corresponding size for use with the positive and negative electrode sheets. The negative electrode sheet is placed on the central shaft of the winding machine, a separator is covered on top of the negative electrode sheet, and then the positive electrode sheet is covered on top of it, forming a "negative electrode-separator-positive electrode" stacked structure. This process continues until the required number of layers or thickness is reached. The stacked materials are then tightly wound into a cylindrical or square core. After winding, the core is fixed with finishing tape.

[0013] Preferably, the membrane is designed with microporous channels inside, through which ions in the electrolyte can freely shuttle, and the pore size of the microporous channels is less than 1 μm.

[0014] Preferably, the genetic algorithm encodes welding parameters as chromosomes, and iteratively optimizes them through selection, crossover, and mutation to find the optimal combination of welding parameters. The optimization steps predetermine the welding optimization objectives, which include maximizing welding strength, laser power, and welding speed. Welding parameter combinations are randomly generated as the initial population. A fitness function is designed according to the objectives, and the merits of each generated parameter combination are evaluated, and the fitness value is calculated. Crossover and mutation operations are performed, and finally, the evaluation, selection, crossover, and mutation operations are repeated for iterative optimization, and the final output is the optimal parameter combination.

[0015] Preferably, the fitness function is:

[0016] F(x) = max[0, Cf(x)]

[0017] Where F(x) is the fitness function, C is a constant, and f(x) is a functional combination of welding parameters;

[0018] The crossover operation is calculated using the arithmetic crossover method. For two individual welding parameters Z1 and Z2, and a random number a, the arithmetic crossover is expressed as:

[0019] B1 = a * Z1 + (1 - a) * Z2

[0020] B2=a*Z2+(1-a)*Z1

[0021] Where B1 is the first offspring, B2 is the second offspring, and a is a random number with a value in the range of 0≤a≤1. The formula generates new offspring individuals by weighting.

[0022] Preferably, the mutation operation is performed using binary mutation. The mutation operation involves inverting the binary representation of the chromosome, changing 0 to 1 in the selected gene position. The mutation steps are as follows: determine the mutation probability, which is between 0.001 and 0.1; select the individual welding parameters to be mutated, based on a random number 'a'; determine the mutation position; perform the mutation operation; generate new parameters; verify the new welding parameters to see if they are the optimal combination of welding parameters; if not, continue to iterate and optimize; if so, output the result.

[0023] Preferably, the path planning algorithm uses particle swarm optimization. The processing steps are as follows: pre-determine each existing welding path, assign an initial position and velocity to each welding path, perform iterative optimization, and update the velocity and position of the welding path. The update formula is:

[0024] V=w1*v1+d1*r1(pB-g1)+d2*r2*(gB-g1)

[0025] Where V is the updated output, v1 and g1 are the velocity and position of the ions respectively, w is the inertia weight, d1 and d2 are the learning factors respectively, r1 and r2 are the random numbers respectively, pB is the individual optimal solution of the welding path, and gB is the global optimal solution. The optimal path in the welding process is obtained through the formula, and the welding movement is carried out according to the path.

[0026] Preferably, the Archimedes spiral is defined by the following equation:

[0027] O = e + hn

[0028] Where O is the radius distance from the origin to the curve, e and h are constants, controlling the initial radius and pitch of the spiral respectively, and n is the angle between the point and the x-axis;

[0029] The heterogeneous sine curve modifies the formula by introducing sinusoidal oscillations along the radius of the spiral:

[0030] r'=(e+hn)+ksin*(jn+m)

[0031] Where k is the amplitude of the control fluctuation, j is the frequency of the control fluctuation, and m is the phase offset, the Archimedes spiral is transformed using the formula.

[0032] Preferably, a real-time monitoring and feedback mechanism is introduced during the welding process to detect the welding quality in real time. If abnormal welding is detected, welding is stopped immediately and the welding parameters are adjusted.

[0033] Preferably, the holes in the manifold are processed by a punch press, and after punching, the outer surface is deburred.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] This invention uses a circular current collector of the same area as a limit to draw an Archimedean spiral, which is longer than a straight line, effectively increasing the flow area. The welding trajectory is consistent with the distribution of the electrode tabs on the battery end face, ensuring equal electron transmission distance between the electrode sheets and reducing the electron transmission distance, thus effectively improving the battery's rate performance. This welding method ensures consistent penetration depth and is compatible with both flattened and stacked cores. The electrode tab thickness of stacked cores varies, with the tabs near the inner and outer sides of the core being thinner than those in the middle. This allows for a larger effective flow area while avoiding the inner and outer sides. Furthermore, it can find the optimal combination of welding parameters for welding and the best welding path for movement, leading to better application prospects. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the cross-section of the wound core of the present invention;

[0037] Figure 2 This is a schematic diagram of the stacked core electrode tab of the present invention;

[0038] Figure 3 This is a top view of the weld bead distribution in the present invention.

[0039] Figure 4 This is a cross-sectional view of the weld bead distribution in a comparative example of the present invention;

[0040] Figure 5 This is a top view of the pre-set weld bead of the manifold in an embodiment of the present invention;

[0041] Figure 6 This is a cross-sectional view of the weld bead distribution in an embodiment of the present invention. Detailed Implementation

[0042] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0043] Reference Figure 1 and Figure 2 As shown, a welding method for a cylindrical battery current collector is described. The welding method is as follows:

[0044] The welding parameters are optimized based on the genetic algorithm to find the optimal combination of welding parameters, and the welding process is carried out using the current combination of welding parameters.

[0045] Based on the path planning algorithm, the path in the welding process is planned and set so that the manifold moves according to the predetermined path during welding.

[0046] The positive and negative electrode plates and the separator are wound together to form a core, and the separator separates the positive and negative electrodes to prevent short circuits.

[0047] The upper end of the core is provided with an upper electrode lug, and the lower end of the core is provided with a lower electrode lug. The upper and lower electrode lugs are welded to the upper and lower current collectors.

[0048] The distribution of the wound cross-section electrode sheet and the electrode lug is an Archimedean spiral, and the welding trajectory is an Archimedean spiral, which is then transformed into a sine curve. The spiral spacing when drawing the Archimedean spiral is a multiple of the electrode lug distribution spacing to ensure that after welding, each area of ​​the electrode lug has a similar weld bead to connect the electrode lug to the current collector.

[0049] When the waveform is transformed into a sine wave, the amplitude is set to be less than the pitch of the Archimedean spiral, and the period is set based on the fact that the inner lines do not intersect.

[0050] Holes are pre-drilled on the collector plate to allow electrolyte to enter the core. The power and time waveform of the welding are precisely set to the light-emitting and non-light-emitting times of each segment, so that the actual light-emitting power is zero at the hole position, and the welding of the collector plate is carried out.

[0051] This application optimizes welding parameters using a genetic algorithm to find the most suitable parameter combination for current materials and process conditions, thereby improving the strength and reliability of the welded joint. The optimized welding parameters can reduce energy waste and material loss during the welding process, thus reducing production costs. The path planning algorithm can ensure that the welded head moves precisely along the predetermined path, avoiding deviation and errors during the welding process. The Archimedean spiral design makes the distribution of the tabs on the core more uniform, and the weld beads also follow the same spiral trajectory, ensuring that each tab can obtain a similar welded connection, improving the overall performance of the battery. The sine wave design can reduce stress concentration during the welding process, reducing the risk of cracking of the welded joint. The hole design on the current collector can ensure that the electrolyte can smoothly enter the core, providing the necessary conditions for the normal operation of the battery.

[0052] The winding process involves inspecting the positive and negative electrode sheets and the separator raw materials, precisely cutting the positive and negative electrode sheets to predetermined dimensions, and cutting the separator to the corresponding size for use with the positive and negative electrode sheets. The negative electrode sheet is placed on the central shaft of the winding machine, a separator is covered on top of the negative electrode sheet, and then the positive electrode sheet is covered on top of it, forming a "negative electrode-separator-positive electrode" stacked structure. This process continues until the required number of layers or thickness is reached. The stacked materials are then tightly wound into a cylindrical or square core. After winding, the core is fixed with finishing tape.

[0053] The positive and negative electrode sheets and separators in this application are precisely cut before winding to ensure that the size and thickness of each layer are consistent, which helps to form a uniform battery structure. The stacked materials are tightly wound into cylindrical or square cores, which helps to reduce internal voids and improve the energy density and overall performance of the battery.

[0054] The membrane is designed with microporous channels inside, through which ions in the electrolyte can freely shuttle. The pore size of the microporous channels is less than 1 μm.

[0055] It effectively prevents dendrites that may form inside the battery from penetrating the separator, further reducing the risk of short circuits and improving the battery's energy density.

[0056] The genetic algorithm encodes welding parameters as chromosomes and iteratively optimizes them through selection, crossover, and mutation to find the optimal combination of welding parameters. The optimization steps predetermine the welding optimization objectives, which include maximizing welding strength, laser power, and welding speed. Welding parameter combinations are randomly generated as the initial population. A fitness function is designed according to the objectives, and the merits of each generated parameter combination are evaluated, and the fitness value is calculated. Crossover and mutation operations are performed, and finally, the evaluation, selection, crossover, and mutation operations are repeated for iterative optimization, and the final output is the optimal parameter combination.

[0057] The fitness function is:

[0058] F(x) = max[0, Cf(x)]

[0059] Where F(x) is the fitness function, C is a constant, and f(x) is a functional combination of welding parameters;

[0060] The crossover operation is calculated using the arithmetic crossover method. For two individual welding parameters Z1 and Z2, and a random number a, the arithmetic crossover is expressed as:

[0061] B1 = a * Z1 + (1 - a) * Z2

[0062] B2=a*Z2+(1-a)*Z1

[0063] Where B1 is the first offspring, B2 is the second offspring, and a is a random number with a value in the range of 0≤a≤1. The formula generates new offspring individuals by weighting.

[0064] The mutation operation uses binary mutation, which involves inverting the binary representation of the chromosome, changing 0s to 1s in the selected gene positions. The mutation steps are as follows: determine the mutation probability (between 0.001 and 0.1), select the individual welding parameters to be mutated (based on a random number 'a'), determine the mutation location, perform the mutation operation, generate new parameters, and verify these new welding parameters to see if they are the optimal combination. If not, continue iterative optimization; if so, output the result.

[0065] The welding parameter encoding in this application is prior art and will not be elaborated further. Arithmetic crossover is a crossover method used for real number-encoded chromosomes. It generates offspring chromosomes by performing arithmetic operations between two parent chromosomes and is suitable for optimization problems involving continuous variables.

[0066] The path planning algorithm uses particle swarm optimization. The steps are as follows: pre-determine each existing welding path, assign an initial position and velocity to each path, perform iterative optimization, and update the velocity and position of the welding paths using the following formula:

[0067] V=w1*v1+d1*r1(pB-g1)+d2*r2*(gB-g1)

[0068] Where V is the updated output, v1 and g1 are the velocity and position of the ions respectively, w is the inertia weight, d1 and d2 are the learning factors respectively, r1 and r2 are the random numbers respectively, pB is the individual optimal solution of the welding path, and gB is the global optimal solution. The optimal path in the welding process is obtained through the formula, and the welding movement is carried out according to the path.

[0069] The equation for the Archimedes spiral is:

[0070] O = e + hn

[0071] Where O is the radius distance from the origin to the curve, e and h are constants, controlling the initial radius and pitch of the spiral respectively, and n is the angle between the point and the x-axis;

[0072] The heterogeneous sine curve modifies the formula by introducing sinusoidal oscillations along the radius of the spiral:

[0073] r'=(e+hn)+ksin*(jn+m)

[0074] Where k is the amplitude of the control fluctuation, j is the frequency of the control fluctuation, and m is the phase offset, the Archimedes spiral is transformed using the formula.

[0075] In this application, the particle swarm optimization algorithm simulates birds in a flock by designing massless particles. These particles have only two attributes: velocity and position. Velocity represents the speed of movement, and position represents the direction of movement. Each particle searches for the optimal solution independently in the search space and records it as the current individual extreme value pB. At the same time, all particles in the swarm share the optimal solution found by the entire swarm, which is called the global extreme value gB. All particles in the swarm adjust their velocity and position based on their current individual extreme value and the current global optimal solution shared by the entire swarm.

[0076] A real-time monitoring and feedback mechanism is introduced during the welding process to detect the welding quality in real time. If abnormal welding is detected, welding is stopped immediately and the welding parameters are adjusted.

[0077] The holes in the manifold are processed by a punch press. After punching, the outer surface is deburred.

[0078] Example 1

[0079] Reference Figure 5 and Figure 6 As shown, the positive and negative electrode sheets and the separator are wound to form a core. The upper and lower ends of the core have positive and negative electrodes, respectively. The positive and negative electrodes are flattened to form a welding area. The upper and lower electrode welding areas are laser-welded to positive and negative current collectors. The current collectors are circular with 5 φ6mm liquid injection holes evenly distributed. The actual light-emitting segments and the actual non-light-emitting segments are numbered in sequence. The welding time of the first segment is 120ms and the light-emitting power is set to 0. The light-emitting time of the second segment is 500ms and the light-emitting power is set to 100% of the preset power. And so on. The total welding time is the sum of the welding times of all segments, as shown in Table 1 below.

[0080] Table 1 shows the segmented welding time and power.

[0081] Wire bonding number 1 2 3 4 5 6 7 8 9 10 11 12 13 Welding time (ms) 120 500 40 80 40 85 40 90 40 95 40 100 10 Light output power (%) 0 100 0 100 0 100 0 0 0 100 0 100 0

[0082] After welding, the casing is inserted to continue the subsequent liquid injection, sealing and baking processes.

[0083] Real-time Example 2

[0084] Reference Figure 5 and Figure 6As shown, the positive and negative electrode sheets and the separator are wound to form a core. The upper and lower ends of the core have positive and negative tabs, respectively. The positive and negative tabs are die-cut to form welding areas. The upper and lower tab welding areas are laser-welded to positive and negative current collectors. The current collectors are circular with 5 φ6mm liquid injection holes evenly distributed. The actual light-emitting segments and the actual non-light-emitting segments are numbered in sequence. The welding time of the first segment is 120ms, and the light-emitting power is set to 0. The light-emitting time of the second segment is 500ms, and the light-emitting power is set to 100% of the preset power. And so on. The total welding time is the sum of the welding times of all segments. Since the thickness of the tabs is slightly thinner near the outer edge of the die-cut tab core, the light-emitting power of the outer ring is set to 80% of the preset power, as shown in Table 2 below.

[0085] Table 2 shows the segmented welding time and power.

[0086] Wire bonding number 1 2 3 4 5 6 7 8 9 10 11 12 13 Welding time (ms) 120 500 40 80 40 85 40 90 40 95 40 100 10 Light output power (%) 0 100 0 100 0 100 0 80 0 80 0 80 0

[0087] After welding, the casing is inserted to continue the subsequent liquid injection, sealing and baking processes.

[0088] Comparative Example 1

[0089] Reference Figure 3 and Figure 4 As shown, appropriate laser power, welding speed, and focal position parameters are set based on the material and thickness of the collector plate and electrode.

[0090] Welding process: Start the laser welding equipment and focus the laser beam on the contact surface between the collector and the electrode post;

[0091] The laser beam rapidly melts the material at the contact surface, forming a molten pool;

[0092] Before the molten pool solidifies, keep the relative positions of the manifold and the electrode stable to ensure the strength of the weld and complete the welding.

[0093] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A method for welding current collectors for cylindrical batteries, characterized in that, The welding method is as follows: The welding parameters are optimized based on the genetic algorithm to find the optimal combination of welding parameters, and the welding process is carried out using the current combination of welding parameters. Based on the path planning algorithm, the path in the welding process is planned and set so that the manifold moves according to the predetermined path during welding. The positive and negative electrode plates and the separator are wound together to form a core, and the separator separates the positive and negative electrodes to prevent short circuits. The upper end of the core is provided with an upper electrode lug, and the lower end of the core is provided with a lower electrode lug. The upper and lower electrode lugs are welded to the upper and lower current collectors. The distribution of the wound cross-section electrode sheet and the electrode lug is an Archimedean spiral, and the welding trajectory is an Archimedean spiral, which is then transformed into a sine curve. The spiral spacing when drawing the Archimedean spiral is a multiple of the electrode lug distribution spacing to ensure that after welding, each area of ​​the electrode lug has a similar weld bead to connect the electrode lug to the current collector. When the waveform is transformed into a sine wave, the amplitude is set to be less than the pitch of the Archimedean spiral, and the period is set based on the fact that the inner lines do not intersect. Holes are pre-drilled on the collector plate to allow electrolyte to enter the core. The power and time waveform of the welding are precisely set to the light-emitting and non-light-emitting time of each segment, so that the actual light-emitting power is zero at the hole position, and the welding of the collector plate is carried out. The genetic algorithm encodes welding parameters into chromosomes and iteratively optimizes them through selection, crossover, and mutation to find the optimal combination of welding parameters. The optimization steps predetermine the welding optimization objectives, which include maximizing welding strength, laser power, and welding speed. Welding parameter combinations are randomly generated as the initial population. A fitness function is designed according to the objectives. Each generated parameter combination is evaluated for its merits and its fitness value is calculated. Crossover and mutation operations are performed. Finally, the evaluation, selection, crossover, and mutation operations are repeated for iterative optimization, and the final output is the optimal parameter combination. The fitness function is: , Where F(x) is the fitness function, C is a constant, and f(x) is a functional combination of welding parameters; The crossover operation is calculated using the arithmetic crossover method. For two individual welding parameters Z1 and Z2, and a random number a, the arithmetic crossover is expressed as: B1 = a * Z1 + (1 - a) * Z2 B2 = a * Z2 + (1 - a) * Z1 Where B1 is the first offspring, B2 is the second offspring, and a is a random number with a value in the range of 0≤a≤1. The formula generates new offspring individuals by weighting.

2. The method for welding the current collector of a cylindrical battery according to claim 1, characterized in that, The winding process involves inspecting the positive and negative electrode sheets and the separator raw materials, precisely cutting the positive and negative electrode sheets to predetermined dimensions, and cutting the separator to the corresponding size for use with the positive and negative electrode sheets. The negative electrode sheet is placed on the central shaft of the winding machine, a separator is covered on top of the negative electrode sheet, and then the positive electrode sheet is covered on top of it, forming a "negative electrode-separator-positive electrode" stacked structure. This process continues until the required number of layers or thickness is reached. The stacked materials are then tightly wound into a cylindrical or square core. After winding, the core is fixed with finishing tape.

3. The method for welding the current collector of a cylindrical battery according to claim 1, characterized in that, The membrane is designed with microporous channels inside, through which ions in the electrolyte can freely shuttle. The pore size of the microporous channels is less than 1 μm.

4. The method for welding the current collector of a cylindrical battery according to claim 1, characterized in that, The mutation operation uses binary mutation, which involves inverting the binary representation of the chromosome, changing 0s to 1s in the selected gene positions. The mutation steps are as follows: determine the mutation probability (between 0.001 and 0.1), select the individual welding parameters for the mutation based on a random number 'a', determine the mutation location, perform the mutation operation, generate new parameters, and verify these new welding parameters to see if they are the optimal combination. If not, continue iterative optimization; if so, output the result.

5. The method for welding the current collector of a cylindrical battery according to claim 1, characterized in that, The path planning algorithm uses particle swarm optimization. The steps are as follows: pre-determine each existing welding path, assign an initial position and velocity to each path, perform iterative optimization, and update the velocity and position of the welding paths using the following formula: , Where V is the updated output, v1 and g1 are the velocity and position of the ion, w1 is the inertia weight, d1 and d2 are the learning factors, r1 and r2 are random numbers, pB is the individual optimal solution of the welding path, and gB is the global optimal solution. The optimal path in the welding process is obtained through the formula, and the welding movement is carried out according to the path.

6. The method for welding the current collector of a cylindrical battery according to claim 1, characterized in that, The Archimedean spiral is defined by the equation: O = e + hn. Where O is the radius distance from the origin to the curve, e and h are constants, controlling the initial radius and pitch of the spiral respectively, and n is the angle between the point and the x-axis; The heterogeneous sine curve modifies the formula by introducing sinusoidal oscillations along the radius of the spiral: , Where k is the amplitude of the control fluctuation, j is the frequency of the control fluctuation, and m is the phase offset, the Archimedes spiral is transformed using the formula.

7. The method for welding the current collector of a cylindrical battery according to claim 1, characterized in that, A real-time monitoring and feedback mechanism is introduced during the welding process to detect the welding quality in real time. If abnormal welding is detected, welding is stopped immediately and the welding parameters are adjusted.

8. The method for welding the current collector of a cylindrical battery according to claim 1, characterized in that, The holes in the manifold are processed by a punch press. After punching, the outer surface is deburred.

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