A battery cell preparation method and battery cell

Abstract

The present invention provides a method for preparing a cell and a cell. The method comprises: placing a cell to be cut on a cutting platform; determining laser parameters of a laser and determining platform parameters of the cutting platform; controlling the operation of the cutting platform based on the platform parameters, and controlling the laser to cut the cell based on the laser parameters to form continuous laser ablation points on the cell; wherein a preset spacing exists between two adjacent laser ablation points. By controlling the spacing between the laser ablation points formed by the laser cutting on the cell surface, secondary ablation caused by a subsequent laser spot to the area surrounding the laser ablation point formed by the previous laser spot can be reduced, thereby reducing thermal damage to the cell caused by the laser spot, thereby reducing the loss of cell cutting efficiency.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a method for preparing a cell and a cell. Background Art

[0002] Half-cell technology involves laser-slicing the entire solar cell in a direction perpendicular to the main grid of the cell, then welding and connecting them in series to form a module. Half-cell modules have lower packaging losses and reduce the risk of hot spot effects. Therefore, half-cell modules have become the mainstream in the market.

[0003] In related technologies, laser cutting technology is used to irradiate the surface of the battery cell with laser. The temperature at the laser spot reaches above the melting point of the silicon material, causing the silicon material in contact to directly vaporize or melt, thereby forming continuous grooves on the surface of the battery cell, and then mechanically breaking the cell to form half a battery cell.

[0004] However, the inventors found in their research that due to the high temperature of laser cutting, thermal damage would be caused to the battery cells around the cutting area, resulting in a significant loss in the cutting efficiency of the battery cells. Summary of the Invention

[0005] The embodiments of the present invention provide a method for preparing a battery cell and a battery cell to solve the problem in the prior art that the high laser cutting temperature may cause thermal damage to the battery cells around the cutting area, resulting in a significant loss in the cutting efficiency of the battery cells.

[0006] In a first aspect, an embodiment of the present invention provides a method for preparing a battery cell, comprising:

[0007] Place the battery cell to be cut on the cutting platform;

[0008] Determining laser parameters of a laser used to cut the cell, and determining platform parameters of the cutting platform;

[0009] The cutting platform is controlled to operate based on the platform parameters, and the laser is controlled to cut the cell based on the laser parameters to form continuous laser ablation points on the cell; wherein a preset distance exists between two adjacent laser ablation points.

[0010] Optionally, the laser parameters include a laser spot diameter, and the laser parameters for determining the laser used to cut the cell include:

[0011] determining a laser waveform of the laser;

[0012] Within the frequency range of the laser waveform, the laser frequency of the laser is adjusted to adjust the spot diameter of the laser so that the spot diameter is within a preset range.

[0013] Optionally, the platform parameters include a moving speed of the cutting platform, and the moving speed is positively correlated with the spot diameter.

[0014] Optionally, after adjusting the laser frequency of the laser to adjust the spot diameter of the laser, the method further includes:

[0015] The distance between the cell and the laser light source is adjusted to correct the spot diameter, wherein the laser light source is used to emit the laser.

[0016] Optionally, placing the battery sheet to be cut on a cutting platform includes:

[0017] Fixing the battery cell on the cutting platform by vacuum adsorption;

[0018] The adjusting the distance between the cell and the laser light source includes:

[0019] The vacuum adsorption pressure of the cutting platform on the battery cell is adjusted to adjust the distance between the battery cell and the laser light source.

[0020] Optionally, the preset spacing is 0 to 0.5 times the diameter of the light spot.

[0021] Optionally, the preset range of the light spot diameter is 10-30 μm.

[0022] Optionally, the preset laser waveform is a spike-shaped waveform.

[0023] Optionally, the laser frequency of the laser is 25-40 KHz.

[0024] Optionally, the platform moving speed is 2000-3000 mm / s.

[0025] Optionally, the vacuum adsorption pressure is -1.6 to -2.5 Pa.

[0026] Optionally, the laser parameters further include: the number of laser scans and single laser energy, and the laser parameters determined further include:

[0027] The number of scans and the single laser energy are adjusted so that the depth of the laser ablation point reaches a preset depth.

[0028] Optionally, the single laser energy is 0.2-0.6W.

[0029] Optionally, the number of scans is 12 to 16 times.

[0030] Optionally, the preset depth is 0.4 to 0.7 times the thickness of the battery cell.

[0031] In a second aspect, an embodiment of the present invention provides a cell, wherein an edge of at least one side of the cell has an arc-shaped tooth structure, wherein the arc-shaped tooth structure is formed by continuous ablation of a laser spot;

[0032] The arc-shaped tooth structure includes a plurality of arc-shaped tooth grooves arranged continuously and at intervals, and the center distance between the two arcs corresponding to two adjacent arc-shaped tooth grooves is not less than a preset value.

[0033] Optionally, the curvature radius of the circular arc corresponding to each of the plurality of arc-shaped tooth grooves is equal.

[0034] Optionally, the preset value is 2.0 to 3.0 times the curvature radius.

[0035] Optionally, the bending direction of the arc corresponding to the arc-shaped tooth groove is away from the edge, and the depth of the arc-shaped tooth groove along the bending direction is not less than the curvature radius of the arc line.

[0036] Optionally, the edge of the battery cell includes: a split layer and a scribing layer, the split layer and the scribing layer are stacked; and the edge of the scribing layer has the arc-shaped tooth structure.

[0037] Compared with the prior art, the present invention has the following advantages:

[0038] In an embodiment of the present invention, by determining the laser parameters of the laser used to cut the cell and the platform parameters of the cutting platform, the operation of the cutting platform is controlled based on the platform parameters, and the laser is controlled to cut the cell based on the laser parameters, so that the laser cuts the cell surface to form a series of laser ablation points, and each laser ablation point has a preset spacing between adjacent laser ablation points. By controlling the spacing between the laser ablation points formed by the laser cutting on the cell surface, it is possible to reduce the secondary ablation caused by the subsequent laser spot to the area surrounding the laser ablation point formed by the previous laser spot, thereby reducing the thermal damage to the cell caused by the laser spot, thereby reducing the loss of cell cutting efficiency.

[0039] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments.

[0041] Figure 1 A schematic diagram of a process for preparing a battery cell according to an embodiment of the present invention;

[0042] Figure 2 A schematic diagram of a laser waveform provided by an embodiment of the present invention;

[0043] Figure 3a A schematic diagram of a laser waveform in the related art provided by an embodiment of the present invention;

[0044] Figure 3b A schematic diagram of a laser waveform provided by an embodiment of the present invention;

[0045] Figure 4 A schematic flow chart of another method for preparing a battery cell according to an embodiment of the present invention;

[0046] Figure 5 A schematic diagram of the distance between two adjacent laser ablation points provided by an embodiment of the present invention;

[0047] Figure 6a A light microscope image of the surface of a cell in the related art provided by an embodiment of the present invention;

[0048] Figure 6b A light microscope image of a cross section of a battery cell in the related art provided by an embodiment of the present invention;

[0049] Figure 7a A light microscope image of a cut surface of a cell provided by an embodiment of the present invention;

[0050] Figure 7b A light microscope image of a cross section of a battery cell provided by an embodiment of the present invention;

[0051] Figure 8 A schematic structural diagram of a battery cell provided by an embodiment of the present invention;

[0052] Figure 9 A top view of a battery cell provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0053] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention may be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0054] Before explaining the battery cell manufacturing method and battery cell provided by the embodiment of the present invention, the application scenario of the battery cell manufacturing method provided by the embodiment of the present invention is specifically described:

[0055] Crystalline silicon heterojunction cells (SHJ cells), also known as intrinsic thin-film heterojunction cells, use an N-type silicon wafer as a substrate. On either side of the substrate, an intrinsic layer, a doping layer, a transparent conductive oxide (TCO), and printed electrodes are deposited. Compared to traditional crystalline silicon cells, SHJ cells offer high efficiency, symmetrical structure, simple processing steps, excellent temperature characteristics, high open-circuit voltage, and high bifacial power generation efficiency. In recent years, they have become a mainstream solar cell technology.

[0056] In related technologies, laser cutting is used to cut crystalline silicon heterojunction cells. Laser cutting is a thermal separation technology. When a laser is irradiated on the cell surface, the temperature at the laser spot reaches above the melting point of the silicon material (1410°C), causing the silicon material to directly vaporize or melt. Because crystalline silicon heterojunction cells are manufactured using a low-temperature process, the TCO film and amorphous silicon film layers are significantly damaged during the laser cutting process, resulting in a significant loss in heterojunction cell cutting efficiency.

[0057] Among them, cutting efficiency loss refers to the loss of photoelectric conversion efficiency of solar cells before and after cutting. For example, the photoelectric conversion efficiency of the crystalline silicon heterojunction cell before cutting is 23%, and the photoelectric conversion efficiency of the crystalline silicon heterojunction cell after cutting is 22.6%, and the cutting efficiency loss is 0.4%.

[0058] Based on the above problems, the present invention provides a battery cell preparation method and a battery cell to solve the problem that the high laser cutting temperature will cause thermal damage to the battery cells around the cutting area, resulting in a significant loss in battery cell cutting efficiency.

[0059] Figure 1 A method for preparing a battery cell provided by an embodiment of the present invention includes:

[0060] Step 101: Place the battery cell to be cut on a cutting platform.

[0061] In an embodiment of the present invention, laser cutting equipment can be used to cut the front or back of a cell. The front of a cell refers to the side of the cell facing the sun, and the back of a cell refers to the side of the cell facing away from the sun. The laser cutting equipment may include a cutting platform and a laser light source. The cutting platform is used to support and secure the cell to be cut, and the laser light source is used to emit laser light for cutting the cell.

[0062] The cell to be cut is placed on a cutting platform to fix the cell. Specifically, the cutting platform can also support the cell to move relative to the laser light source so that the laser light emitted by the laser light source continuously cuts the cell, wherein the laser light source may include a laser emitter.

[0063] Step 102: Determine laser parameters of a laser used to cut the cell, and determine platform parameters of the cutting platform.

[0064] In an embodiment of the present invention, the parameter setting interface of the laser light source and the parameter setting interface of the cutting platform can be opened, and the laser parameters of the laser used to cut the battery cells can be set in the parameter setting interface of the laser light source, and the platform parameters of the cutting platform can be set in the parameter setting interface of the cutting platform.

[0065] The laser parameters may include: laser waveform, laser spot diameter, and platform parameters may include: cell size parameters, platform movement speed, vacuum pressure, etc. Of course, the specific laser parameters and platform parameters can be set according to actual needs, and the present invention does not impose any restrictions on this.

[0066] Step 103: Control the cutting platform to operate based on the platform parameters, and control the laser to cut the cell based on the laser parameters, so as to form continuous laser ablation points on the cell; wherein a preset distance exists between two adjacent laser ablation points.

[0067] In an embodiment of the present invention, according to the determined laser parameters, the laser light source is controlled to emit laser toward the battery cell placed on the cutting platform. When the laser is projected onto the surface of the battery cell, a laser spot is formed. Under the action of the high temperature of the laser spot, the area covered by the laser spot is ablated to form a laser ablation point.

[0068] The cutting platform is controlled according to the set platform parameters. The cutting platform can carry the cell and move relative to the laser light source, so that the laser continuously ablates the cell surface and forms a series of laser ablation points on the cell surface. Specifically, by controlling the operation of the cutting platform and the laser, the laser cuts the cell surface to form a series of laser ablation points, and there is a preset spacing between two adjacent laser ablation points.

[0069] like Figure 5 As shown, the distance between two adjacent laser ablation points is L, and a preset value of the distance can be predetermined as the preset distance, wherein the preset distance can be set to be greater than or equal to zero. Of course, the specific preset distance can be set according to actual needs, and the embodiment of the present invention does not limit this.

[0070] It is understood that when a laser is used to cut the surface of a cell, the laser light emitted by the laser light source is projected onto the surface of the cell to form a laser spot. Under the high-temperature ablation effect of the laser spot, the material in the area covered by the laser spot will directly vaporize or melt, thereby ablating to form laser ablation points in the area covered by the laser spot. Through the relative movement of the laser light source and the cell, the laser light emitted by the laser light source ablates the surface of the cell to form multiple continuous laser ablation points. The area of the laser ablation points is substantially the same as the area of the laser spot.

[0071] It should be noted that multiple continuous laser ablation points can be arranged in a straight line or a curve. Of course, they can also be arranged in other shapes. Those skilled in the art can set them according to actual needs, and the embodiments of the present invention do not limit this.

[0072] Furthermore, due to the high temperature of the laser, the part of the cell near the area covered by the laser spot will also be affected by the high temperature of the laser. Under the influence of the high temperature of the laser, the structure of this part will be thermally damaged, which will in turn affect the photoelectric conversion effect of this part and cause a loss of cutting efficiency.

[0073] It should be noted that as the laser light source and the battery cell move relative to each other, the laser emitted by the laser light source will project continuous laser spots on the surface of the battery cell. When there is an overlapping area between the front and rear laser spots, the rear laser spot will cause secondary ablation to the area around the laser ablation point formed by the previous laser spot, thereby increasing the laser energy received per unit area of the battery cell, expanding the area around the laser ablation point affected by the laser high temperature, and increasing the cutting efficiency loss of the battery cell.

[0074] By setting a preset distance between two adjacent laser ablation points, that is, there is a preset distance between the front and rear laser spots projected by the laser on the surface of the battery cell, the secondary ablation caused by the latter laser spot to the area around the previous laser ablation point can be reduced, which helps to reduce the loss of battery cell cutting efficiency.

[0075] In an embodiment of the present invention, by determining the laser parameters of the laser used to cut the cell and the platform parameters of the cutting platform, the operation of the cutting platform is controlled based on the platform parameters, and the laser is controlled to cut the cell based on the laser parameters, so that the laser forms a continuous laser ablation point on the cell surface, and each laser ablation point is separated from the adjacent laser ablation point by a preset spacing. By controlling the spacing between the laser ablation points formed by the laser cutting on the cell surface, the secondary ablation caused by the subsequent laser spot to the area surrounding the previous laser ablation point when a new laser ablation point is formed can be reduced, thereby reducing the thermal damage to the cell caused by the laser spot, thereby reducing the loss of cell cutting efficiency.

[0076] refer to Figure 4 , an embodiment of the present invention provides another method for preparing a battery cell, which specifically includes the following steps:

[0077] Step 201: Place the battery cell to be cut on a cutting platform.

[0078] In the embodiment of the present invention, the specific implementation process of this step can be performed with reference to step 101 and will not be repeated here.

[0079] Step 202: Determine the laser waveform of the laser.

[0080] In the embodiment of the present invention, a plurality of different laser waveforms can be pre-set in the laser light source. When in use, the desired laser waveform can be selected through the parameter setting interface of the laser light source, so that the laser light source will emit laser light of the corresponding laser waveform. Figure 2 As shown, the laser waveforms preset in the laser light source may include multiple types, and lasers with different laser waveforms correspond to different laser frequency ranges and pulse widths.

[0081] When dicing the cell, the laser waveform of the laser required for cutting the cell is set through the laser light source setting interface. Figure 3b As shown, a laser waveform with a relatively short pulse duration can be selected to reduce the thermal radiation damage of the laser to the solar cell.

[0082] Step 203 : Adjust the laser frequency of the laser within the frequency range of the laser waveform to adjust the spot diameter of the laser so that the spot diameter is within a preset range.

[0083] In an embodiment of the present invention, after determining the laser waveform of the laser required for cutting the battery cell, the specific laser frequency of the laser is adjusted within the frequency range corresponding to the laser waveform so that the laser light source emits laser light of the corresponding laser frequency to the surface of the battery cell.

[0084] By adjusting the laser frequency, the diameter of the laser spot projected onto the cell surface can be adjusted to keep it within a preset range. This allows the ablation effect of the laser spot to form a correspondingly sized laser ablation spot on the cell surface. Lasers of different laser frequencies are selected for cell cutting to control the size of the resulting laser ablation spot, minimizing thermal damage to the area surrounding the laser ablation spot while still maintaining the desired cell surface cutting effect.

[0085] Step 204: Determine the platform parameters of the cutting platform.

[0086] In an embodiment of the present invention, a setting interface of the cutting platform may be opened, and platform parameters of the cutting platform may be set in the setting interface of the cutting platform.

[0087] The platform parameters may include: platform moving speed, vacuum pressure, etc. Of course, the specific platform parameters can be set according to actual needs, and the embodiment of the present invention does not limit this.

[0088] Step 205: Control the cutting platform to operate based on the platform parameters, and control the laser to cut the cell to form continuous laser ablation points on the cell; wherein a preset distance exists between two adjacent laser ablation points.

[0089] In an embodiment of the present invention, a laser is projected onto the surface of the cell to form a circular laser spot. Due to the high-temperature ablation effect of the laser, the area on the surface of the cell covered by the laser spot will be ablated to form a laser ablation point. The shape and size of the laser ablation point are basically the same as the shape and size of the laser spot.

[0090] By setting the platform parameters of the cutting platform and controlling the operation of the cutting platform based on the platform parameters, the cutting platform carries the battery cell and moves relative to the laser light source, so that the laser emitted by the laser light source projects a continuous laser spot on the surface of the battery cell. The continuous laser spot will ablate on the surface of the battery cell to form a continuous laser ablation point. The distance between the two front and rear laser spots is controlled so that there is a preset distance between the two adjacent laser ablation points in the continuous laser ablation points formed by ablation.

[0091] Optionally, after adjusting the laser frequency of the laser to adjust the spot diameter of the laser in step 203, the method further includes: adjusting the distance between the cell and the laser light source to correct the spot diameter, wherein the laser light source is used to emit the laser.

[0092] In an embodiment of the present invention, the cell to be cut is fixed to a cutting platform, and the laser light emitted by a laser light source is projected onto the surface of the cell to form a laser spot. The ablation effect of the laser spot is then utilized to cut the cell. The diameter of the laser spot varies with the distance between the laser light source and the cell. For example, as the distance between the laser light source and the cell increases, the diameter of the laser spot projected by the laser on the cell surface increases accordingly. Therefore, by adjusting the distance between the cell and the laser light source, the diameter of the laser spot projected onto the cell surface can be adjusted.

[0093] Optionally, step 201 includes: fixing the battery cell on the cutting platform by vacuum adsorption;

[0094] In an embodiment of the present invention, a vacuum adsorption structure is provided on the cutting platform. The cell to be cut is placed on the vacuum adsorption structure of the cutting platform. The vacuum adsorption effect of the vacuum adsorption structure secures the cell to the cutting platform. As the cutting platform moves, the cell moves along with it, minimizing relative slippage between the cell and the cutting platform. Using vacuum adsorption to secure the cell to the cutting platform facilitates loading and unloading of the cell.

[0095] Furthermore, the adjusting the distance between the cell and the laser light source includes: adjusting the vacuum adsorption pressure of the cutting platform on the cell to adjust the distance between the cell and the laser light source.

[0096] In an embodiment of the present invention, the distance between the cell and the laser light source can be adjusted by adjusting the vacuum adsorption pressure of the vacuum adsorption structure on the cutting platform on the cell, thereby adjusting the spot diameter of the laser spot projected onto the surface of the cell.

[0097] It is understood that the cell is fixed to the side of the cutting platform facing the laser light source, with the cell positioned between the laser light source and the cutting platform. The laser light emitted by the laser light source projects onto the cell surface to form a laser spot, which is then used to ablate the cell. Specifically, the cell is fixed to the cutting platform using vacuum suction, and the position of the cell on the cutting platform can be adjusted by adjusting the vacuum suction pressure of the cutting platform on the cell.

[0098] When the vacuum pressure of the cutting platform on the cell is increased, the cell moves toward the cutting platform, and the distance between the cell and the laser source increases. Conversely, when the vacuum pressure of the cutting platform on the cell is reduced, the cell moves away from the cutting platform, and the distance between the cell and the laser source decreases. Therefore, by adjusting the vacuum pressure of the cutting platform on the cell, the distance between the cell and the laser source is adjusted, thereby correcting the spot diameter and improving cutting accuracy.

[0099] Optionally, the platform parameters include a moving speed of the cutting platform, and the moving speed is positively correlated with the spot diameter.

[0100] In the embodiment of the present invention, the platform parameters include at least the moving speed of the cutting platform. The distance between two adjacent laser ablation points can be adjusted by controlling the laser spot diameter and the moving speed of the cutting platform.

[0101] It can be understood that in order to make the distance between two adjacent laser ablation points reach the preset spacing, the moving speed is positively correlated with the spot diameter, that is, when the laser spot diameter increases, the moving speed of the cutting platform is increased to ensure that the distance between two adjacent laser ablation points reaches the preset spacing; conversely, when the laser spot diameter decreases, the moving speed of the cutting platform is reduced accordingly to ensure that the distance between two adjacent laser ablation points reaches the preset spacing.

[0102] For example, in the first case, the length of the cell to be cut is 100mm, the spot diameter of the laser spot is set to 2mm, and the preset spacing between two adjacent laser spots is 2mm. Then, using this laser spot, 25 continuous laser ablation points can be formed on the 100mm cell. In the second case, the length of the cell to be cut is still 100mm, the spot diameter is set to 1mm, and the spacing between the spots is 1mm. Then, using this laser spot, 50 continuous laser ablation points can be formed on the 100mm cell. Assuming that the laser forms one laser ablation point per second, for the first case, the laser needs to run for 25s, which is a relatively short time. Under the same stroke, the moving speed of the cutting platform is relatively fast. For the second case, the laser needs to run for 50s, which is a relatively long time. Under the same stroke, the moving speed of the cutting platform is relatively slow.

[0103] Of course, the specific values of the laser spot diameter and the moving speed of the cutting platform can be determined according to actual needs, and the embodiment of the present invention does not limit this.

[0104] In an embodiment of the present invention, the spot diameter is adjusted based on the laser waveform and laser frequency so that the spot diameter is within a preset range. The cutting platform is controlled to operate based on platform parameters, and the laser is controlled to cut the surface of the cell, so that the laser ablates the cell to form continuous laser ablation points, and a preset spacing exists between two adjacent laser ablation points in the formed continuous laser ablation points. The size of the spot diameter is controlled to control the size of each laser ablation point, thereby reducing the range of thermal damage around the laser ablation point while meeting the cutting requirements; and by controlling the spacing between the laser ablation points formed by the laser ablation on the cell surface, the secondary ablation caused by the subsequent laser spot to the area around the laser ablation point formed by the previous laser spot can be reduced, which can reduce the thermal damage to the cell caused by the laser spot, thereby reducing the loss of cutting efficiency of the cell.

[0105] Optionally, the preset spacing is 0 to 0.5 times the diameter of the light spot.

[0106] In the embodiment of the present invention, Figure 5As shown, the diameter of the laser spot is D, that is, the diameter of the laser ablation point is D. The spacing between two adjacent laser spots is L, that is, the spacing between two adjacent laser ablation points is L. Specifically, the preset spacing L between two adjacent laser spots can be set to 0 to 0.5 times the spot diameter D. Optionally, the preset spacing L can be set to any value such as 0, 0.1, 0.2, 0.3, 0.4, or 0.5 times the spot diameter D.

[0107] It is understood that the preset spacing between two adjacent laser spots is determined based on the spot diameter. When the spot diameter is larger, the preset spacing is larger. Lasers with larger spot diameters have better cutting effects on the cell, making it easier to smoothly cut the cell. However, this also increases the area of thermal damage to the cell caused by the laser spot. Therefore, the preset spacing is increased accordingly to reduce the thermal damage caused by the subsequent laser spot to the laser ablation point formed by the previous laser spot. Conversely, when the spot diameter is smaller, the preset spacing is reduced, thereby ensuring smooth cell cutting while reducing thermal damage to the cell caused by the laser spot.

[0108] Of course, the specific values of the preset spacing L and the spot diameter D can be set according to actual needs, and the embodiment of the present invention does not limit this.

[0109] Optionally, the preset range of the light spot diameter is 10-30 μm. Specifically, the light spot diameter can be set to any value such as 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, etc.

[0110] Optionally, the full width at half maximum of the laser pulse is 11 to 24 ns.

[0111] In an embodiment of the present invention, Figure 3a is the laser waveform in the related art, Figure 3b is the laser waveform of the embodiment of the present invention. The integral area of the curve and the horizontal axis in the figure is the total heat of the laser in unit time. Figure 3a and Figure 3b It can be seen that the total heat per unit time corresponding to the laser waveform selected in the embodiment of the present invention is significantly smaller than the total heat per unit time corresponding to the laser waveform in the related art, thereby reducing the continuous thermal damage of the laser to the battery cell.

[0112] Specifically, the full width at half maximum (FWHM) of the laser pulse used to cut the cell is set to 11 to 24 ns. Optionally, the FWHM can be any value, such as 11 ns, 12 ns, 14 ns, 16 ns, 19 ns, 22 ns, or 24 ns. By adjusting the FWHM of the laser pulse, the duration of a single laser pulse is shortened, thereby reducing the total heat generated per unit time by the laser pulse, thereby minimizing thermal damage to the cell surface caused by a single laser pulse.

[0113] It should be noted that the specific value of the full width at half maximum of the pulse of the laser used for cutting the solar cell can be set according to actual needs, and the embodiment of the present invention does not impose any limitation on this.

[0114] Optionally, refer to Figure 3b , one-third pulse width F of the laser is 5 to 20 ns.

[0115] In the embodiment of the present invention, Figure 3a and 3b As shown, Figure 3a A schematic diagram showing a laser waveform in related art is shown. Figure 3b The figure shows a schematic diagram of a laser waveform provided by an embodiment of the present invention, wherein the X-axis represents the pulse time, the Y-axis represents the laser spectrum energy, and the curve in the figure is a function curve of the laser spectrum energy pulse time.

[0116] One-third of the laser pulse width F refers to the distance between the two points before and after the one-third peak value on the laser spectrum energy curve. Figure 3a and 3b In the laser spectrum curve, the two points where the function value is equal to one-third of the peak value are points M and N respectively. The time corresponding to point M is X1, and the time corresponding to point N is X2. The distance between points M and N is one-third of the laser pulse width F.

[0117] Specifically, the one-third pulse width F of the laser can be set to 5 to 20 ns. Optionally, the one-third pulse width F of the laser can be set to any value such as 5 ns, 7 ns, 8 ns, 10 ns, 11 ns, 12 ns, 14 ns, 16 ns, 19 ns, or 20 ns. It should be noted that the specific value of the one-third pulse width F of the laser used for cutting the solar cell can be set according to actual needs and is not limited in this embodiment of the present invention.

[0118] Optionally, the laser frequency of the laser is 25-40KHz. Specifically, the laser frequency of the laser can be set to any value such as 25KHz, 28KHz, 30KHz, 32KHz, 35KHz, 27KHz, 40KHz, etc.

[0119] Optionally, the platform moving speed of the cutting platform is set to 2000-3000 mm / s. Specifically, the platform moving speed can be set to any value such as 2000 mm / s, 2300 mm / s, 2500 mm / s, 2800 mm / s, 3000 mm / s, etc.

[0120] Optionally, the vacuum pressure of the cutting platform is set to -1.6 to -2.5 Pa. Specifically, the vacuum pressure can be set to any value such as -1.6 Pa, -1.8 Pa, -2.0 Pa, -2.2 Pa, and -2.5 Pa.

[0121] In some embodiments, setting the cutting platform parameters also includes setting the size parameters of the cell to control the movement of the cutting platform so that the laser cuts only where the cell is located, thereby preventing damage to the cutting platform. For example, the cell length, cell width, and cell thickness can be set to 166 mm, 166 mm, and 150 μm, respectively.

[0122] Optionally, the laser parameters further include: the number of laser scans and the single laser energy, and the laser parameters determined in step 102 further include:

[0123] The number of scans and the single laser energy are adjusted so that the depth of the laser ablation point reaches a preset depth.

[0124] In an embodiment of the present invention, the laser is controlled to cut the battery cell by setting the number of laser scans and the single laser energy of the laser pulse, so that the depth of each of the continuous laser ablation points formed on the battery cell reaches a preset depth.

[0125] Specifically, during the process of cutting the battery cell, one laser scan will form continuous laser ablation points of a certain depth on the surface of the battery cell. However, the depth of the laser ablation points formed after one scan is very different from the total thickness of the battery cell and cannot meet the cutting requirements. Therefore, multiple laser scans are required to increase the depth of the laser ablation points.

[0126] The amount of laser energy in a single laser pulse determines the depth of the laser ablation point formed by the single laser pulse, as well as the size of the area affected by heat around the laser ablation point. The greater the laser energy in a single laser pulse, the deeper the laser ablation point formed, but the larger the area affected by heat around the laser ablation point formed, the greater the thermal damage to the cell.

[0127] Therefore, the single laser energy and the number of laser scans can be set to meet the cutting requirements of the battery cell while minimizing the thermal damage of the laser to the battery cell.

[0128] Optionally, the single laser energy of the laser pulse can be set to 0.2-0.6 W. Specifically, the single laser energy can be set to any value such as 0.2 W, 0.3 W, 0.4 W, 0.5 W, 0.57 W, or 0.6 W.

[0129] Optionally, the number of laser scans can be set to 12 to 16 times. Specifically, the number of laser scans can be set to any value such as 12, 13, 14, 15, or 16 times.

[0130] In some embodiments, by reducing the single laser energy and increasing the number of laser scans, the thermal radiation energy of the laser is reduced while meeting the cutting requirements for the battery cell, thereby reducing the loss of cutting efficiency.

[0131] Optionally, the preset depth of the laser ablation point can be set to 0.4 to 0.7 times the thickness of the cell. Specifically, the preset depth can be set to any value such as 0.4, 0.5, 0.6, or 0.7 times the thickness of the cell. Of course, the specific preset depth can be determined based on the actual thickness of the cell, and this embodiment of the present invention does not impose any limitation on this.

[0132] In an embodiment of the present invention, the number of laser scans and the single laser energy are set so that the depth of each of the continuous laser ablation points formed by laser ablation on the surface of the battery cell reaches a preset depth. At the same time, the preset depth is set based on the actual thickness of the battery cell to meet the cutting requirements of the battery cell, while reducing the thermal damage of the laser to the parts around the laser ablation points on the battery cell and reducing the loss of cutting efficiency.

[0133] In some embodiments, the process parameters in the related art and the process parameters in the embodiments of the present invention are selected to conduct a cutting test on the battery cell, and the cutting efficiency loss of the battery cell after cutting is tested. The test results are shown in Table 1 below:

[0134] Table 1

[0135]

[0136] In the embodiments of the present invention, as shown in Table 1, Comparative Tests 1, 2, 3, and 4 used cutting process parameters from related art to cut the cell wafers, while the sample test used the cutting process parameters of the embodiments of the present invention to cut the cell wafers. As can be seen from Table 1, compared to Comparative Tests 1-4, the sample test increased the platform movement speed, single laser energy, number of scans, and spot spacing, while reducing the laser frequency, spot diameter, and cutting depth, thereby reducing the loss efficiency of the cell wafer after cutting. The laser spot spacing is the distance between two adjacent laser ablation points.

[0137] In some embodiments, after step 103, the process further includes: breaking the cell along the laser ablation points to obtain cut half-cells. Specifically, after forming continuous laser ablation points on the cell surface through steps 101 to 103, the cell is broken along the continuous laser ablation points so that the cell is naturally broken along the center line connecting the continuous laser ablation points, thereby obtaining two half-cells.

[0138] It should be noted that for the specific method of breaking the battery cell, reference can be made to the relevant art, and the embodiments of the present invention do not limit this.

[0139] In some embodiments, as Figure 6a and 7b As shown, Figure 6a This is a light microscope image of the surface of a solar cell after laser cutting in the related technology. It can be seen from the image that the distance between two adjacent laser ablation points formed by laser cutting is very close, and the two front and rear laser ablation points have a large overlapping area. Therefore, a continuous groove is formed after cutting. The edge of the groove is relatively smooth, and the width of the laser heat-affected zone is relatively wide, such as: the width is 70 to 80 μm, resulting in a large loss of cutting efficiency.

[0140] Figure 6b This is a light microscope image of the cross-section of a battery cell after laser cutting in the related art, wherein the laser is incident from the right side of the image. The bright area in the image is the cross-section formed after the battery cell is broken, and the part to the right of the bright area is the laser cutting area. It can be seen from the image that the cross-section formed after laser cutting is a continuous cross-section.

[0141] like Figure 7a As shown, Figure 7a The optical microscope image of the surface of the battery cell after laser cutting provided in the embodiment of the present invention shows that the laser cuts the surface of the battery cell to form multiple laser ablation points at intervals, and there is a certain distance between two adjacent laser ablation points. Since there is a distance between the two adjacent laser ablation points, the mutual thermal influence between the two laser ablation points is reduced, and the width of the laser heat-affected zone is narrow. For example, the width of the laser heat-affected zone is 50 to 60 μm, which reduces the loss of cutting efficiency.

[0142] Figure 7b An optical microscope image of a cross section of a cell after laser cutting is provided for an embodiment of the present invention, wherein the laser is incident from the right side of the image, and the bright area in the image is the cross section formed after the cell is broken. It can be seen from the image that there is still a cell structure between two adjacent laser-cut sections, and this part of the cell structure has a photoelectric conversion effect. Therefore, compared with the cell after cutting in the related art, the cutting efficiency loss is reduced.

[0143] An embodiment of the present invention further provides a battery cell, wherein the edge of at least one side of the battery cell has an arcuate tooth structure 121, and the arcuate tooth structure 121 is formed by continuous ablation of a laser spot; the arcuate tooth structure 121 includes a plurality of arcuate tooth grooves 121a arranged continuously at intervals, and the center distance between the two arcs corresponding to two adjacent arcuate tooth grooves 121a is not less than a preset value.

[0144] In an embodiment of the present invention, the cell preparation method in the above-mentioned embodiment can be selected, and a laser is used to cut the surface of the cell to be cut, and the cell is broken along the laser ablation point to obtain a cut cell. The edge of at least one side of the cell has an arc-shaped tooth structure 121, and the arc-shaped tooth structure 121 includes a plurality of arc-shaped tooth grooves 121a arranged continuously at intervals. Since the arc-shaped tooth grooves 121a on the cell are formed by laser spot ablation, the center distance of the two arcs corresponding to the two adjacent arc-shaped tooth grooves 121a is set to be not less than a preset value, so that the tooth structure part of the edge of the cell still retains a complete structure and has a photoelectric conversion effect. Compared with the related art, the edge of the cell after cutting is smooth, which can increase the effective light-receiving area of the cell and reduce the loss of cutting efficiency.

[0145] Optionally, the radius of curvature of the arc corresponding to each of the plurality of arc-shaped tooth grooves 121a is equal. In an embodiment of the present invention, by setting the radius of curvature of the arc corresponding to each of the plurality of arc-shaped tooth grooves 121a to be equal, the arc-shaped tooth structures 121 at the edge of the cell are more evenly distributed, thereby improving the uniformity of the photoelectric conversion efficiency of each area of the cell.

[0146] like Figure 9 As shown, Figure 9 The arc corresponding to each arc-shaped tooth groove 121 is a semicircle, and the center distance between the two arcs corresponding to two adjacent arc-shaped tooth grooves 121a is C. The center distance C can be set to be no less than a preset value.

[0147] Optionally, the preset value is 2.0 to 3.0 times the curvature radius.

[0148] In an embodiment of the present invention, the center distance of the two arcs corresponding to two adjacent arc-shaped tooth grooves 121a in the arc-shaped tooth structure 121 is set so that the center distance is 2.0 to 3.0 times the curvature radius of the arc corresponding to the arc-shaped tooth groove 121a, that is, the two arcs corresponding to the two adjacent arc-shaped tooth grooves 121a are tangent or there is a partial gap between them.

[0149] It can be understood that since the arc-shaped tooth groove 121a is formed by the laser spot ablation on the battery surface, by setting the two arcs corresponding to the two adjacent arc-shaped tooth grooves 121a to be tangent or have a partial gap, the thermal impact of the latter laser spot on the area around the previous arc-shaped tooth groove 121a during the laser spot ablation process can be reduced, thereby reducing the cutting efficiency loss of the battery cell and improving the photoelectric conversion performance of the battery cell.

[0150] Alternatively, as Figure 9 As shown, the bending direction of the arc corresponding to the arc-shaped tooth groove 121a is away from the edge, and the depth of the arc-shaped tooth groove 121a along the bending direction is not less than the curvature radius of the arc.

[0151] In an embodiment of the present invention, at least one edge of a cell has an arcuate tooth structure 121. The arcuate tooth structure 121 includes a plurality of arcuate tooth grooves 121a arranged in a continuous and spaced relationship. The arc corresponding to the arcuate tooth grooves 121a curves away from the edge where the arcuate tooth structure 121 is located, and the depth of the arcuate tooth grooves 121a along the curvature direction is not less than the radius of curvature of the arc. As a result, the cell portion between two adjacent arcuate tooth grooves 121a retains its intact structure. Compared to the smoothed edge of the cell after cutting in the related art, this can increase the effective light-receiving area of the cell and improve the photoelectric conversion performance of the cell.

[0152] Specifically, the arc-shaped tooth structure 121 at the edge of the cell is formed by continuous laser spot ablation, such as Figure 9 As shown, the bending direction of the arc corresponding to each arcuate tooth groove 121a in the arcuate tooth structure 121 is away from the edge where the arcuate tooth structure 121 is located, and the depth of the arcuate tooth structure 121 along the bending direction is M, which is not less than the curvature radius of the arc corresponding to the arcuate tooth groove 121a.

[0153] In some embodiments, the arc is a semicircular arc, and the curvature radius is the radius of the semicircular arc.

[0154] Optionally, the edge of the cell includes: a splitting layer 11 and a scribing layer 12 , wherein the splitting layer 11 and the scribing layer 12 are stacked; and the edge of the scribing layer 12 has an arc-shaped tooth structure 121 .

[0155] In an embodiment of the present invention, the edge of the battery cell may include: a split layer 11 and a scribing layer 12, the split layer 11 and the scribing layer 12 are stacked, the edge of the scribing layer 12 has an arc-shaped tooth structure, the arc-shaped tooth structure 121 includes a plurality of arc-shaped tooth grooves 121a arranged continuously at intervals, wherein each arc-shaped tooth groove 121a is recessed from the side surface of the scribing layer 12 away from the split layer 11 toward the split layer 11.

[0156] It should be noted that the specific structural shape and size of the arc-shaped tooth structure at the edge of the scribing layer 12 can be set according to actual needs, and the embodiment of the present invention does not limit this.

[0157] In the embodiment of the present invention, since the position of the arc-shaped tooth grooves of the arc-shaped tooth structure on the cell after cutting corresponds to the area covered by the laser spot ablation, the arc-shaped tooth structure part at the edge of the cell still retains a complete structure and has a photoelectric conversion effect. Compared with the related technology in which the edge of the cell after cutting is smooth, it can increase the effective light-receiving area of the cell and reduce the loss of cutting efficiency.

[0158] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive (SSD)).

[0159] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0160] Each embodiment in this specification is described in a related manner. Similar portions between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments. The embodiments of the apparatus, electronic device, computer-readable storage medium, and computer program product containing instructions thereof are generally similar to the method embodiments, so their description is relatively simple. For related portions, reference can be made to the description of the method embodiments.

[0161] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the scope of protection of the present invention.

Claims

1. A method for preparing a battery cell, characterized in that: include: Placing a cell to be cut on a cutting platform, wherein the cell has a front side and a back side facing each other, and the front side is the side of the cell facing the sun; Determining laser parameters of a laser used to cut the cell, and determining platform parameters of the cutting platform; The cutting platform is controlled to operate based on the platform parameters, and the laser is controlled to cut the front or back of the battery cell based on the laser parameters to form continuous laser ablation points on the front or back of the battery cell; wherein the laser parameters include a spot diameter of the laser, and there is a preset spacing between two adjacent laser ablation points, and the preset spacing is 0 to 0.5 times the spot diameter.

2. The method for preparing a battery cell according to claim 1, wherein: The laser parameters for cutting the cell sheet are determined as follows: determining a laser waveform of the laser; Within the frequency range of the laser waveform, the laser frequency of the laser is adjusted to adjust the spot diameter of the laser so that the spot diameter is within a preset range.

3. The method for preparing a battery cell according to claim 2, wherein: The platform parameters include a moving speed of the cutting platform, and the moving speed is positively correlated with the spot diameter.

4. The method for preparing a battery cell according to claim 2, wherein: After adjusting the laser frequency of the laser to adjust the spot diameter of the laser, the method further includes: The distance between the cell and the laser light source is adjusted to correct the spot diameter, wherein the laser light source is used to emit the laser.

5. The method for preparing a battery cell according to claim 4, wherein: Placing the battery sheet to be cut on the cutting platform includes: Fixing the battery cell on the cutting platform by vacuum adsorption; The adjusting the distance between the cell and the laser light source includes: The vacuum adsorption pressure of the cutting platform on the battery cell is adjusted to adjust the distance between the battery cell and the laser light source.

6. The method for preparing a battery cell according to claim 2, wherein: The preset range of the light spot diameter is 10-30 μm.

7. The method for preparing a battery cell according to claim 1, wherein: The laser pulse half-maximum full width is 11-24 ns.

8. The method for preparing a battery cell according to claim 7, wherein: The laser frequency of the laser is 25-40 KHz.

9. The method for preparing a battery cell according to claim 3, wherein: The platform moving speed is 2000-3000 mm / s.

10. The method for preparing a battery cell according to claim 5, wherein: The vacuum adsorption pressure is -1.6 to -2.5 Pa.

11. The method for preparing a battery cell according to claim 1, wherein: The laser parameters also include: the number of laser scans and the single laser energy. The laser parameters determined also include: The number of scans and the single laser energy are adjusted so that the depth of the laser ablation point reaches a preset depth.

12. The method for preparing a battery cell according to claim 11, wherein: The single laser energy is 0.2-0.6W.

13. The method for preparing a battery cell according to claim 11, wherein: The number of scans is 12 to 16 times.

14. The method for preparing a battery cell according to claim 11, wherein: The preset depth is 0.4 to 0.7 times the thickness of the battery cell.

15. A battery cell, characterized in that: The cell has a front side and a back side facing each other, the front side is the side of the cell facing the sun, and at least one side edge of the front side or at least one side edge of the back side of the cell has an arc-shaped tooth structure; The arc-shaped tooth structure includes a plurality of arc-shaped tooth grooves arranged continuously at intervals, and the center distance between the two arcs corresponding to two adjacent arc-shaped tooth grooves is not less than a preset value, and the preset value is 2.0 to 3.0 times the curvature radius of the arc corresponding to the arc-shaped tooth groove.

16. The battery cell according to claim 15, characterized in that: The curvature radius of the circular arc corresponding to each of the plurality of arc-shaped tooth grooves is equal.

17. The battery cell according to claim 15, characterized in that: The curvature direction of the arc corresponding to the arc-shaped tooth groove is away from the edge, and the depth of the arc-shaped tooth groove along the curvature direction is not less than the curvature radius of the arc line.

18. The battery cell according to claim 15, characterized in that: The edge of the battery cell includes: a split layer and a scribing layer, wherein the split layer and the scribing layer are stacked; and the edge of the scribing layer has the arc-shaped tooth structure.

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