Method for preparing gradient microstructure on surface of current collector
By combining nanosecond and femtosecond pulsed laser beams, gradient microstructures that meet the service performance requirements of current collectors are fabricated, solving the problem of the difficulty in forming microstructures on the substrate surface after laser cleaning, and achieving efficient cleaning and performance improvement.
Patent Information
- Application Number
- CN202511821627.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-04
- Publication Date
- 2026-01-27
AI Technical Summary
Existing technologies make it difficult to form gradient microstructures on the substrate surface after laser cleaning that meet the performance requirements of current collectors.
By employing a beam combining technique of nanosecond pulsed lasers and femtosecond pulsed lasers, the surface of the current collector is scanned, and the output power, pulse width, repetition frequency, and scanning speed of the lasers are controlled to prepare gradient microstructures.
This method enables the preparation of gradient microstructures with good compatibility with electrode active materials, high conductivity, and high mechanical strength without the use of chemical reagents, thus avoiding secondary pollution.
Smart Images
Figure CN121402830A_ABST
Abstract
Description
Technical Field
[0002] This invention relates to the field of laser applications, and more specifically to a method for preparing gradient microstructures on the surface of a current collector. Background Technology
[0003] The cleanliness and morphological state of the current collector surface in power batteries are crucial to battery performance and safety. The microstructure of the current collector surface after cleaning can further affect the overall energy storage and energy-saving behavior. For example, the porosity of the current collector structure and the distribution of lithiophilic sites on the surface are key points for designing excellent 3D current collectors. The use of 3D current collectors can not only reduce local current density, reduce polarization, and suppress dendrite growth by increasing the specific surface area, but the porous structure can also act as a structural framework to hinder volume expansion, effectively mitigating the large volume changes caused by lithium deposition, and promoting the improvement of electrodes and performance.
[0004] Laser surface engineering technology boasts advantages such as being environmentally friendly, high-quality and efficient, causing no secondary damage, simple in process, safe and reliable, easy to automate, and low in operation and maintenance costs. It is an ideal technical means to solve the problem of high-quality, efficient, and green cleaning of thin-walled thermistor components in power batteries. However, forming a gradient microstructure on the substrate surface after laser cleaning that meets the service performance requirements of the current collector is very challenging. Summary of the Invention
[0005] This invention provides a method for preparing gradient microstructures on the surface of a current collector, and the method of this invention prepares gradient microstructures that meet the service performance requirements of the current collector.
[0006] This invention provides a method for preparing gradient microstructures on the surface of a current collector, comprising the following steps: The surface of the current collector is scanned using a combined laser beam; The combined laser beam includes nanosecond pulse lasers and femtosecond pulse lasers; The output power of the nanosecond pulsed laser is 50~100W, and the output power of the femtosecond pulsed laser is 15~30W; The nanosecond pulse laser has a pulse width of 50~500ns and a repetition frequency of 10~50kHz; the femtosecond pulse laser has a pulse width of 50~500fs and a repetition frequency of 10~50kHz. The speed of the combined laser beam during scanning is 1500~3000 mm / s.
[0007] Preferably, the wavelengths of both the nanosecond pulsed laser and the femtosecond pulsed laser are 1064 nm.
[0008] Preferably, the nanosecond pulsed laser has a circular spot shape with a spot diameter of 0.3~0.9mm and a scanning overlap rate of 5~15%.
[0009] Preferably, the femtosecond pulsed laser has a square spot shape, a spot diameter of 0.3~0.9mm, and a scanning overlap rate of 5~15%.
[0010] Preferably, the spot size of the femtosecond pulse laser is larger than the spot size of the nanosecond pulse laser.
[0011] Preferably, the spot of the nanosecond pulsed laser is embedded in the spot of the femtosecond pulsed laser.
[0012] Preferably, the scanning interval of the combined laser beam during scanning is 0.10~0.15mm, and the defocusing amount is 125±3mm.
[0013] Preferably, the current collector comprises copper foil or aluminum foil.
[0014] Preferably, before the scanning, the process further includes cleaning the current collector.
[0015] Preferably, the cleaning method includes reciprocating scanning in an S-shape using a nanosecond pulsed laser.
[0016] This invention employs a multi-mode laser combining nanosecond pulsed laser and femtosecond pulsed laser. While maintaining high cleaning efficiency to obtain a homogeneous clean substrate, it also prepares a gradient microstructure that meets the service performance requirements of the current collector by adjusting the output power, pulse width, repetition frequency, and scanning speed of the nanosecond pulsed laser and femtosecond pulsed laser. This microstructure exhibits excellent compatibility and bonding with the electrode active material, high conductivity, and high mechanical strength.
[0017] Furthermore, the method of this invention does not use chemical reagents, does not generate wastewater or dust, and does not cause secondary contaminant adhesion to the current collector, thus belonging to green laser surface engineering technology. Attached Figure Description
[0018] Figure 1 This is a process flow diagram of Example 1; Figure 2 This is a schematic diagram illustrating the process of fabricating gradient microstructures on the surface of a multi-mode laser-cleaned current collector in Example 1. Figure 3 This is a simulation image of a single microstructure used in Example 1 to prepare gradient microstructures on the surface of a multi-mode laser-cleaned current collector. Figure 4 This is a scanning electron microscope image of the gradient microstructure prepared on the surface of the multi-mode laser cleaning current collector in Example 1; Figure 5 The image shows a scanning electron microscope (SEM) image of the microstructure prepared on the surface of the single-mode laser-cleaned current collector in Comparative Example 1. Detailed Implementation
[0019] This invention provides a method for preparing gradient microstructures on the surface of a current collector, comprising the following steps: The surface of the current collector is scanned using a combined laser beam; The combined laser beam includes nanosecond pulse lasers and femtosecond pulse lasers; The output power of the nanosecond pulsed laser is 50~100W, and the output power of the femtosecond pulsed laser is 15~30W; The nanosecond pulse laser has a pulse width of 50~500ns and a repetition frequency of 10~50kHz; the femtosecond pulse laser has a pulse width of 50~500fs and a repetition frequency of 10~50kHz. The speed of the combined laser beam during scanning is 1500~3000 mm / s.
[0020] Before the scanning, the present invention preferably cleans the current collector.
[0021] In this invention, the cleaning method preferably includes reciprocating scanning in an S-shape using a nanosecond pulsed laser.
[0022] In this invention, the current collector preferably comprises copper foil or aluminum foil. In this invention, the wavelength of the nanosecond pulsed laser during reciprocating scanning is preferably 1064 nm, the output power is preferably 50-100 W, the pulse width is preferably 50-500 ns, the repetition frequency is preferably 10-50 kHz, the spot shape is preferably square, the spot diameter is preferably 0.3-0.9 mm, and the scanning overlap rate is preferably 5-15%. In specific embodiments of this invention, the output power of the nanosecond pulsed laser during reciprocating scanning can be 60 W, 70 W, 80 W, or 90 W, the pulse width can be 100 ns, 200 ns, 300 ns, or 400 ns, the repetition frequency can be 20 kHz, 30 kHz, or 40 kHz, the spot diameter can be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm, and the scanning overlap rate can be 8%, 10%, or 12%.
[0023] In this invention, during the scanning process, the wavelength of the nanosecond pulsed laser is preferably 1064 nm, the output power is 50-100 W, the pulse width is 50-500 ns, the repetition frequency is 10-50 kHz, the spot shape is circular, the spot diameter is preferably 0.3-0.9 mm, and the scanning overlap rate is preferably 5-15%. In specific embodiments of this invention, the output power of the nanosecond pulsed laser during the scanning process can be 60, 70 W, 80 W, or 90 W, the pulse width can be 100 ns, 200 ns, 300 ns, or 400 ns, the repetition frequency can be 20 kHz, 30 kHz, or 40 kHz, the spot diameter can be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm, and the scanning overlap rate can be 8%, 10%, or 12%.
[0024] In this invention, during the scanning process, the wavelength of the femtosecond pulsed laser is preferably 1064 nm, the output power is 15~30 W, the pulse width is 50~500 fs, the repetition frequency is 10~50 kHz, the spot shape is square, the spot diameter is preferably 0.3~0.9 mm, and the scanning overlap rate is preferably 5~15%. In specific embodiments of this invention, the output power of the femtosecond pulsed laser during the scanning process can be 18, 20 W, 25 W, or 28 W, the pulse width can be 100 fs, 200 fs, 300 fs, or 400 fs, the repetition frequency can be 20 kHz, 30 kHz, or 40 kHz, the spot diameter can be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, or 0.8 mm, and the scanning overlap rate can be 8%, 10%, or 12%.
[0025] In this invention, the spot size of the femtosecond pulsed laser is preferably larger than that of the nanosecond pulsed laser, and the spot of the nanosecond pulsed laser is more preferably embedded within the spot of the femtosecond pulsed laser. This nested arrangement of square and round shapes is more conducive to fabricating gradient microstructures that improve the service performance of the current collector.
[0026] The positive correlation between cleaning efficiency and output power, while taking into account the integrity protection of the copper foil (or aluminum foil) current collector substrate, ensures that the output power of femtosecond pulse laser and nanosecond pulse laser during scanning will not cause damage to the surface.
[0027] In this invention, the scanning spacing of the combined laser beam during scanning is preferably 0.10~0.15mm, the speed is preferably 1500~3000mm / s, and the defocusing amount is preferably 125±3mm. In specific embodiments of this invention, the scanning spacing can be 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1mm, 1.2mm or 1.4mm, and the speed can be 1800mm / s, 2000mm / s, 2200mm / s, 2400mm / s, 2500mm / s or 2800mm / s.
[0028] In this invention, the average depth of the gradient microstructure is preferably 100±20nm.
[0029] The following detailed description of the method for preparing gradient microstructures on the surface of a current collector provided by the present invention, with reference to specific embodiments, is not intended to limit the scope of protection of the present invention.
[0030] Figure 1 This is a process flow diagram for Example 1.
[0031] Example 1 Step 1: Select a single nanosecond pulse laser with a wavelength of 1064nm, a power of 100W, a repetition frequency of 25kHz, a laser pulse width of 100ns, and a Gaussian circular spot diameter of 0.4mm.
[0032] Step 2: Focus the multi-mode laser onto the surface of the copper foil current collector with a defocusing distance of 125mm and a scanning speed of 1000mm / s in an S-shaped reciprocating scan to remove surface particles and obtain a clean surface.
[0033] Step 3: Readjust the parameters of the multi-mode laser: The multi-mode laser is a "nanosecond pulse + femtosecond pulse" beam, both with a wavelength of 1064nm and a power matching of "nanosecond pulse 50W + femtosecond pulse 15W".
[0034] Step 4: Select a nanosecond pulse laser with a repetition frequency of 25kHz, a pulse width of 100ns, and a Gaussian circular spot diameter of 0.4mm from the multi-mode laser.
[0035] Step 5: Select a femtosecond pulse laser with a repetition frequency of 25kHz, a pulse width of 200fs, and a flat-top square spot with a side length of 0.6mm from the multi-mode laser.
[0036] Step 6: Select multi-mode laser scanning parameters: scanning speed is 2500mm / s, scanning interval is 0.15mm, and the overlap rate of the flat-top femtosecond laser scanning in the multi-mode laser is 5%.
[0037] Step 7: Focus the multi-mode laser onto the cleaned copper foil current collector surface with a defocusing distance of 125mm and perform an S-shaped reciprocating scan to form a nested microstructure with a certain depth gradient on the copper foil current collector surface.
[0038] Figure 2 This is a schematic diagram illustrating the process of fabricating gradient microstructures on the surface of a multi-mode laser-cleaned current collector in Example 1. Figure 3 This is a simulation image of a single microstructure used in Example 1 to prepare gradient microstructures on the surface of a multi-mode laser-cleaned current collector. Figure 4The image shows the three-dimensional morphology of the gradient microstructure prepared on the surface of the multi-mode laser cleaning current collector in Example 1.
[0039] Comparative Example 1 To compare with the preparation of gradient microstructures on the surface of the current collector using multi-mode laser cleaning in Implementation 1, nanosecond single-mode laser cleaning of the current collector surface was used.
[0040] Step 1: Select a single nanosecond pulse laser with a wavelength of 1064nm, a power of 100W, a repetition frequency of 25kHz, a laser pulse width of 100ns, and a Gaussian circular spot diameter of 0.4mm.
[0041] Step 2: Focus the single-mode laser onto the surface of the copper foil current collector with a defocusing distance of 125mm and a scanning speed of 1000mm / s. Use an S-shaped reciprocating scan to remove surface particles and obtain a clean surface.
[0042] Step 3: Focus the single-mode laser onto the cleaned copper foil current collector surface according to the above parameters and continue the S-shaped reciprocating scan.
[0043] Figure 5 Scanning electron microscope image of gradient microstructures prepared on the surface of the single-mode laser cleaning current collector in Comparative Example 1.
[0044] Depend on Figure 5 It can be seen that the microstructure of the single-body laser cleaning current collector surface is a square-shaped, densely packed fish scale pattern. Each microstructure "pit" is characterized by thin walls around the edges and a concave center. The bottom of the concave center is smooth, and there is no secondary concavity. It does not have the characteristics of a gradient microstructure.
[0045] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing gradient microstructures on the surface of a current collector, characterized in that, Includes the following steps: The surface of the current collector is scanned using a combined laser beam; The combined laser beam includes nanosecond pulse lasers and femtosecond pulse lasers; The output power of the nanosecond pulsed laser is 50~100W, and the output power of the femtosecond pulsed laser is 15~30W; The nanosecond pulse laser has a pulse width of 50~500ns and a repetition frequency of 10~50kHz; the femtosecond pulse laser has a pulse width of 50~500fs and a repetition frequency of 10~50kHz. The speed of the combined laser beam during scanning is 1500~3000 mm / s.
2. The method according to claim 1, characterized in that, The wavelengths of both the nanosecond pulsed laser and the femtosecond pulsed laser are 1064 nm.
3. The method according to claim 1, characterized in that, The nanosecond pulsed laser has a circular spot shape with a spot diameter of 0.3~0.9mm and a scanning overlap rate of 5~15%.
4. The method according to claim 1, characterized in that, The femtosecond pulsed laser has a square spot shape, a spot diameter of 0.3~0.9mm, and a scanning overlap rate of 5~15%.
5. The method according to claim 1, 3, or 4, characterized in that, The spot size of the femtosecond pulse laser is larger than that of the nanosecond pulse laser.
6. The method according to claim 5, characterized in that, The spot of the nanosecond pulsed laser is embedded in the spot of the femtosecond pulsed laser.
7. The method according to claim 1, characterized in that, The scanning interval of the combined laser beam during scanning is 0.10~0.15mm, and the defocusing amount is 125±3mm.
8. The method according to claim 1, characterized in that, The current collector includes copper foil or aluminum foil.
9. The method according to claim 1, characterized in that, Before the scan, the process also includes cleaning the current collector.
10. The method according to claim 9, characterized in that, The cleaning method includes reciprocating scanning in an S-shape using a nanosecond pulsed laser.