Laser-induced sintering processing method and device

Abstract

The invention provides a laser-induced sintering processing method which is applied to an 0BB double-sided electrode battery, a first electrode and a second electrode are adopted to make contact with all thin grid lines on the front face of a battery piece and all thin grid lines on the back face of the battery piece respectively, and a laser beam is controlled to scan the battery piece while reverse voltage is applied to the battery piece through the first electrode and the second electrode; the first electrode comprises N strip-shaped electrodes which are arranged at intervals; each strip-shaped electrode is vertically intersected and contacted with all the fine grid lines on the front surface of the battery piece; the width, needing to be scanned at a time, of the battery piece is divided into a plurality of areas, so that the distance between the strip-shaped electrode and the laser scanning area is shortened, the current density of each thin grid line is improved, the contact specific surface area of metal particles and silicon is increased, the contact resistance of the metal grid lines is reduced, and the service life of the battery piece is prolonged. Therefore, the purpose of high-efficiency laser-induced sintering of the 0BB double-sided electrode battery is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of photovoltaics, and in particular relates to a processing method and a device for laser induced sintering. Background Art

[0002] Laser induced sintering technology requires pressing the probe onto the metallized grid line of the cell, applying a reverse bias voltage while using a laser to scan the cell. Conventional MBB Topcon cells have metallized grid lines on the front and back, and main grid lines on the front and back. When laser induced sintering is performed, the electrode connected to the power supply is brought into contact with the main grid line of the cell to apply a reverse voltage.

[0003] For MBB's Topcon battery, since it has multiple main grid lines, there are more paths for current conduction. During the laser induced sintering scanning process, the electrode only needs to contact at least one main grid line at any position on the surface of the battery cell, and then the laser scans the entire surface area of ​​the battery cell or the grid line area on the surface of the battery cell. The current conduction path runs along the shortest distance. Therefore, MBB's Topcon battery only needs to add a certain bias voltage and laser power to achieve the requirements of reducing contact resistance and meet the efficiency improvement of laser sintering.

[0004] However, for the 0BB Topcon battery, since there is no main grid on the front and back of the battery cell, if the existing MBB Topcon battery electrode contacts the battery cell surface and the laser scanning method is continued to be used (that is, a single probe row is used, during the first processing, the probe presses the left area of ​​the battery cell and assumes the position when the main grid line is present, and the laser scans the right side of the battery cell; during the second processing, the probe presses the right area of ​​the battery cell and assumes the position when the main grid line is present, and the laser scans the left side of the battery cell), since there is no current conduction by the main grid line, the current conduction distance is based on the single conduction of the thin grid line. The current conduction distance is long, the current transmission is single, and the contact resistance on the grid line will be relatively large, which will affect the fill factor FF of the battery cell, reduce the contact effect, increase the contact resistance, reduce the efficiency, and fail to meet the purpose of improving the efficiency of laser sintering. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a laser induced sintering processing method and device to improve the efficiency of laser sintering.

[0006] The technical solution adopted by the present invention to solve the above technical problems is:

[0007] As a first aspect of the present invention, the present invention provides a laser induced sintering processing method, which is applied to a double-sided electrode battery of 0BB, comprising:

[0008] The first electrode and the second electrode are used to contact all the fine grid lines on the front side and all the fine grid lines on the back side of the cell respectively, and a reverse voltage is applied to the cell through the first electrode and the second electrode while controlling the laser beam to scan the cell; wherein,

[0009] All the fine grid lines on the front of the battery cell are arranged in sequence along the first direction, and each of the fine grid lines is continuously extended along the second direction, and the first direction is perpendicular to the second direction; the first electrode includes N strip electrodes arranged at intervals, and each strip electrode is perpendicularly intersected and contacts all the fine grid lines on the front of the battery cell; the width required to be scanned by the battery cell is evenly divided into 2N partitions, and every other partition has one strip electrode, and the strip electrode is located in the partition;

[0010] When controlling the laser beam to scan the cell: first scan the partition without strip electrodes; then shift all the strip electrodes in the same direction by the size of a partition to the partition that has been scanned, and then laser scan the remaining partitions.

[0011] According to the above solution, the N strip electrodes of the first electrode are arranged at equal intervals, and the strip electrodes are located in the middle of the partition.

[0012] According to the above scheme, when the format of the battery cell is 182mm×182mm, the value range of N is a natural number of 2-6; when the format of the battery cell is 210mm×210mm, the value range of N is a natural number of 2-7.

[0013] As a second aspect of the present invention, the present invention also provides a laser induced sintering processing method, which is applied to a double-sided electrode battery of 0BB, comprising:

[0014] The first electrode and the second electrode are used to contact all the fine grid lines on the front side and all the fine grid lines on the back side of the cell respectively, and a reverse voltage is applied to the cell through the first electrode and the second electrode while controlling the laser beam to scan the cell; wherein,

[0015] All the fine grid lines on the front side of the cell are arranged in sequence along the first direction, and each of the fine grid lines is continuously extended along the second direction, and the first direction is perpendicular to the second direction; the first electrode includes a plurality of strip electrodes arranged in sequence at equal or non-equal intervals along the second direction, and each of the strip electrodes is extended along the first direction;

[0016] When controlling the laser beam to scan the cell, each strip electrode corresponds to a laser scanning area, and the distance between the edge of the strip electrode in the second direction and any position in the corresponding laser scanning area is d, and d is 5 mm to 60 mm;

[0017] The laser beam is controlled to scan the required scanning width of the battery sheet twice, and after the first scanning is completed, each of the strip electrodes is controlled to deviate a certain distance along the second direction.

[0018] According to the above scheme, after the first scan is completed, each of the strip electrodes is controlled to translate in the same or different directions along the second direction for the same or different distances, and then the second scan is performed.

[0019] According to the above solution, the width of one of the strip electrodes in the second direction ranges from 3 mm to 9 mm.

[0020] According to the above solution, the strip electrodes are probe rows, which include a support and a plurality of probes connected to the support, and all the fine grid lines are contacted by the probes.

[0021] According to the above solution, the plurality of probes of one strip electrode are divided into two probe units separately arranged along the second direction, and the two probe units are staggered in the second direction.

[0022] According to the above scheme, during scanning, a laser beam is used to scan successively, and after scanning one partition, the next partition to be scanned is scanned; or, several laser beams are used, each laser beam corresponds to a partition to be scanned, and scanned simultaneously.

[0023] As a third aspect of the present invention, the present invention further provides a device for completing the laser induced sintering processing method, comprising:

[0024] A processing table, used for carrying the battery sheet;

[0025] a first electrode and a second electrode;

[0026] Laser scanning device;

[0027] The moving mechanism is used for moving the processing table and / or the first electrode.

[0028] The beneficial effects of the present invention are:

[0029] The laser induced sintering method of the present application is aimed at the double-sided electrode battery of 0BB. By adopting multiple strip electrodes to shorten the distance between the strip electrodes and the laser scanning area, the current density of each fine grid line is increased, and the specific surface area of ​​the contact between the metal particles and silicon is increased, thereby reducing the contact resistance of the metal grid line, thereby achieving the purpose of efficient laser induced sintering of the double-sided electrode battery of 0BB.

[0030] In addition, compared with a single probe row, multiple rows of probe rows (strip electrodes) can maintain uniformity of applied voltage over a larger area of ​​the cell, and the voltage drop at the far end of the probe row is lower than that of a single probe row. Therefore, compared with the method of using a single probe row, this method can reduce the applied reverse voltage, thereby reducing problems caused by excessive voltage, such as black masses appearing at the edge of the cell, sparking on the table (at this time, the cell is placed on a conductive table, and there is a conductive plate on the surface of the conductive table, which acts as a second electrode in contact with the back of the cell), etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the strip electrode structure on the front side of a battery cell according to an embodiment of the present invention.

[0032] Figure 2 It is a schematic diagram of the scanning partition structure of the front side of the battery cell during the first scanning according to an embodiment of the present invention.

[0033] Figure 3 It is a schematic diagram of the scanning partition structure of the front side of the battery cell during the second scanning according to an embodiment of the present invention.

[0034] Figure 4 This is a schematic diagram of the scanning partition structure of the front side of the battery cell during the first scanning according to another embodiment of the present invention.

[0035] Figure 5 This is a schematic diagram of the scanning partition structure of the front side of the battery cell during the second scanning according to another embodiment of the present invention.

[0036] Figure 6 FIG. 1 is a detailed diagram of a strip electrode according to an embodiment of the present invention.

[0037] In the figure: 1-front side of the battery cell, 2-thin grid line, 3-strip electrode, 3-1-probe, 4-scanning partition, 4-1-first scanning partition, 4-2-first non-scanning partition, 4-1'-second non-scanning partition, 4-2'-second scanning partition. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with specific examples and drawings.

[0039] Glossary

[0040] MBB: Multi-Busbar.

[0041] Double-sided electrode battery: A battery with electrodes on both the front and back sides, with a positive electrode on one side and a negative electrode on the other side, such as a typical Topcon battery.

[0042] Topcon: Tunnel Oxide Passivated Contact, tunnel oxide passivated contact.

[0043] 0BB: 0-Busbar, no main grid.

[0044] Fine grid lines: A professional term, in which the "fine" is used to distinguish it from the main grid lines, which are thinner than the main grid lines. When there are main grid lines, the fine grid lines are several parallel grid lines perpendicular to the main grid lines. When there are no main grid lines, there are only fine grid lines on the battery cell.

[0045] Embodiment 1:

[0046] This embodiment provides a laser induced sintering processing method, which is applied to a double-sided electrode battery of 0BB, such as a Topcon battery, and includes the following steps:

[0047] S1. Place the battery cell on a conductive table, the conductive table serves as the second electrode, contacts the back of the battery cell, and can contact all the fine grid lines on the back. For example, the conductive table includes a carrier and a conductive plate arranged on the surface of the carrier, and the conductive plate serves as the second electrode. The conductive plate in the conductive table is usually metal and connected to a conductive member, and the conductive member is connected to an external power supply. The second electrode can also take other forms, as long as it can be guaranteed to contact all the fine grid lines on the back. For example, the second electrode has the same structure as the first electrode, and the second electrode is also a probe row. At this time, the processing table where the battery cell is placed may not be a conductive table, but the processing table needs to be partially hollowed out so that the second electrode passes through the hollowed-out part to contact all the fine grid lines on the back of the battery cell when laser-induced sintering is required. Considering that the specific structure of the second electrode is not the focus of this application, it will not be repeated here.

[0048] S2. Use a first electrode to contact all the thin grid lines on the front side of the battery cell. The first electrode includes N strip electrodes arranged at intervals. Each strip electrode is perpendicular to and intersects all the thin grid lines on the front side of the battery cell.

[0049] The vertical intersection is as follows: Figure 1 As shown, all the fine grid lines 2 on the front side 1 of the cell are arranged in sequence along the first direction Y, each fine grid line 2 is continuously extended along the second direction X, a plurality of strip electrodes 3 are arranged in sequence along the second direction X, each strip electrode 3 is extended along the first direction Y, and the first direction Y is perpendicular to the second direction X. During processing, each strip electrode 3 contacts all the fine grid lines 2 on the front side 1 of the cell.

[0050] The area to be scanned of the cell is evenly divided into 2N partitions, with each partition having a strip electrode, and the strip electrode is located in the partition. The area to be scanned refers to the area covering the outer contours of all fine grid lines on the cell.

[0051] Preferably, the N strip electrodes 3 of the first electrode are arranged at equal intervals, and the strip electrodes 3 are located in the middle of the partition, for example Figure 1 As shown, the strip electrodes 3 are distributed along the second direction X at equal intervals.

[0052] When the cell format is 182mm×182mm, the value range of N is a natural number from 2 to 6, i.e. one of 2, 3, 4, 5, and 6; when the cell format is 210mm×210mm, the value range of N is a natural number from 2 to 7, i.e. one of 2, 3, 4, 5, 6, and 7. If there are too few strip electrodes, the current transmission distance is too long to achieve the effect; if there are too many strip electrodes, more shielding will block the laser and thus affect the laser processing effect.

[0053] Each strip electrode needs to contact all the thin grid lines on the front side. Preferably, the strip electrode is a probe row, each probe of the probe row contacts a thin grid line, and all the thin grid lines are contacted by the probe. More specifically, the probe row includes a bracket and a plurality of probes connected to the bracket, and all the thin grid lines are contacted by the probe. More preferably, Figure 6 As shown, multiple probes of a strip electrode 3 are divided into two probe units 3-1 arranged separately along the second direction, and the two probe units 3-1 are staggered in the second direction and respectively contact the thin gate lines 2. Of course, the strip electrode can also be other structures, such as a continuous strip-shaped electrode sheet.

[0054] S3, controlling the laser beam to scan the cell while applying a reverse voltage to the cell through the first electrode and the second electrode.

[0055] When controlling the laser beam to scan the cell: first scan the partition without strip electrodes; then shift all strip electrodes in the same direction by the size of a partition, into the partition that has been scanned, and then laser scan the remaining partitions. When the N strip electrodes of the first electrode are arranged at equal intervals, the strip electrodes are located in the middle of the partition before and after the shift.

[0056] Furthermore, when laser scanning is used for the cell, a partition scanning method is adopted, where a laser beam is used to scan one partition at a time, and after scanning one partition, the next partition to be scanned is scanned. Alternatively, several laser beams may be used, each corresponding to a partition to be scanned, and the scanning is performed simultaneously, which is more efficient. Several laser beams may be obtained by means of spectroscopy.

[0057] Specifically, taking N=3, that is, the first electrode includes 3 strip electrodes as an example, the entire width of the battery cell is divided into 6 partitions. Figure 2As shown, during the first scan, the first, third, and fifth sub-areas are used as the first scan sub-areas 4-1, and the second, fourth, and sixth sub-areas are used as the first non-scan sub-areas 4-2. The three strip electrodes 3 are respectively arranged in the middle of the first non-scan sub-areas 4-2. During the laser scanning, three laser beams are scanned. The three laser beams can be obtained by splitting the laser emitted by a laser, or by using a laser to emit a laser beam for sequential scanning. During the second scan, as shown in FIG. Figure 3 As shown, the first scanning partition 4-1 has completed scanning and becomes the second non-scanning area 4-1', and the first non-scanning partition 4-2 becomes the second scanning area 4-2'. By moving the strip electrodes and / or the battery cell, all the strip electrodes 3 can be offset by the size of a partition in the same direction to the middle of the second non-scanning area 4-1', and the laser scans the second scanning area 4-2', thereby completing the laser scanning of the entire width of the front side of the battery cell and completing the laser induced sintering.

[0058] The laser induced sintering method of the present application is aimed at the double-sided electrode battery of 0BB. By adopting multiple strip electrodes to shorten the distance between the strip electrodes and the laser scanning area, the current density of each fine grid line is increased, and the specific surface area of ​​the contact between the metal particles and silicon is increased, thereby reducing the contact resistance of the metal grid line, thereby achieving the purpose of efficient laser induced sintering of the double-sided electrode battery of 0BB.

[0059] When the strip electrode is located in the middle of each partition, the current transmission distance on the left and right sides of each partition is equal. The current transmission paths are increased and the current transmission uniformity is high, which can effectively reduce the contact resistance between the fine gate line and silicon.

[0060] Furthermore, the number of strip electrodes is inversely proportional to the number of reverse voltages applied. Specifically, the applicant has found that because the line resistivity of the 0BB battery is relatively small, the reverse current per unit area increases, and the voltage needs to be increased to increase the current acting on the battery cell and reduce the contact resistance; when the number of strip electrodes is too small, even if the reverse voltage is increased, the corresponding effect cannot be achieved, and when the number of strip electrodes is appropriate, the more the number of strip electrodes, the lower the reverse voltage applied, and the corresponding contact resistivity requirements can be met.

[0061] Embodiment 2:

[0062] The principle and scheme of this embodiment are basically the same as those of the first embodiment, except that:

[0063] like Figure 4As shown, the strip electrodes 3 are arranged in sequence along the second direction at equal or unequal intervals, and the number and position of the required strip electrodes 3 are set according to the effective range of the current transmission distance. When the laser beam is controlled to scan the cell, each strip electrode 3 corresponds to a laser scanning area 4, and the distance between the edge of the strip electrode 3 in the second direction and any position in the corresponding laser scanning area 4 is d, and d is 5mm to 60mm. When d is less than 5mm, the strip electrode 3 may block the laser scanning; when d is greater than 60mm, the current conduction distance is far, the current transmission is single, and the contact resistance on the gate line will be relatively large, which affects the filling factor FF of the cell, reduces the contact effect, increases the contact resistance, reduces the efficiency, and fails to meet the purpose of improving the efficiency of laser sintering.

[0064] Further Figure 4 As shown, d1 is the closest distance between the edge of the strip electrode 3 in the second direction and the corresponding scanning area, and d2 is the farthest distance between the edge of the strip electrode 3 in the second direction and the corresponding scanning area. Therefore, d1 needs to be greater than or equal to 5 mm, and d2 needs to be less than or equal to 60 mm.

[0065] It should be noted that Figure 4 It is only a schematic diagram, and the strip electrode 3 in the figure only looks thin, and the display does not represent the width of the strip electrode 3. In addition, according to the description, the strip electrode 3 is at a certain distance from the corresponding scanning area, so those skilled in the art can understand that the edge of the strip electrode 3 in the second direction is the edge close to the corresponding scanning area 4.

[0066] The laser beam is controlled to scan the required scanning width of the battery sheet twice, and after the first scanning is completed, each strip electrode is controlled to deviate a certain distance along the second direction.

[0067] More specifically, after the first scan is completed, each strip electrode 3 is controlled to translate in the same direction or in a non-same direction along the second direction for a same or different distance, and then a second scan is performed; wherein, the same direction can be understood as all the strip electrodes 3 are in the positive direction of the second direction or in the negative direction of the second direction, and the non-same direction can be understood as some strip electrodes translate in the positive direction of the second direction, and some translate in the negative direction of the second direction. Figure 5As shown, each strip electrode 3 is simultaneously offset by a distance in the positive direction of the second direction. In addition, the distances by which each strip electrode is offset in the second direction may be the same or different. In some embodiments, two adjacent strip electrodes 3 may move toward each other in the second direction, or move away from each other in the second direction. For example, during the first laser scanning process, the scanning area may be located on the left side of the strip electrode, and during the second laser scanning process, the scanning area may be located on the right side of the strip electrode. As one example, when the number of strip electrodes is 2, the two areas between the two strip electrodes (these two areas may be connected) are scanned first, and during the second laser scanning process, the two areas outside the two strip electrodes are scanned.

[0068] It should also be noted that when the turntable of the prior art is used as a carrier to switch the processing stations for two laser scans, the two laser scans are completed in two stations. The change in the position relationship of the strip electrode 3 mentioned above mainly refers to the change in the position relationship between the strip electrode and the projection of the battery cell in the horizontal plane after the battery cell is moved into place at the two processing stations. In this case, both processing stations have strip electrodes, and the number of strip electrodes at the two stations is the same. The number of strip electrodes in the text refers to the number of corresponding strip electrodes at one processing station, and the translation of the strip electrodes in the text is actually the offset of the projection relationship at the first processing station relative to the projection relationship at the second station. Of course, it is also possible to complete two laser scans at one station, in which case the strip electrode can be considered to be moved, and the number of strip electrodes at this station can be considered to be the number of strip electrodes in the text.

[0069] It should also be noted that during each single laser scan, the position of any strip electrode is not located in the area covered by position 1 and position 2, so as to avoid blocking the laser scanning and affecting the processing effect; wherein position 1 is the edge of the strip electrode adjacent to the strip electrode, and position 2 is the position of the scanning area of ​​the adjacent strip electrode farthest from the adjacent strip electrode.

[0070] During each scan, a laser beam is used to scan successively, and after scanning one laser scanning area, the next laser scanning area is scanned; or, several laser beams are used, each laser beam corresponds to a laser scanning area, and scans simultaneously.

[0071] Furthermore, the width of a strip electrode in the second direction ranges from 3 mm to 9 mm. For example, when it is a single row, its width can be as thin as 3 mm, and when it is a double row as described above (including two probe units 3 - 1 ), it will be slightly wider.

[0072] It can be seen from the above embodiments that multiple strip electrodes are used to contact the fine grid lines at the same time and energize them, and the distance between the laser beam scanning area and the strip electrodes is limited, so that when the laser beam is scanning, the current transmission distance is appropriate, the current density of each fine grid line is increased, and the contact resistance of the metal grid line is reduced; while increasing the current transmission path, the arrangement method can be diversified, which can be more flexible and can also ensure efficient laser induced sintering process effects.

[0073] As a second aspect of the present invention, the present invention also provides a device for completing the above-mentioned laser induced sintering processing method, including a processing table for carrying a battery cell, the processing table including a conductive table top as a second electrode; a first electrode; a laser scanning device; and a moving mechanism for moving the processing table and / or the first electrode.

[0074] The present invention sets a suitable number of strip electrodes and their arrangement positions, energizes each strip electrode, limits the distance between the scanning area and the strip electrode, thereby shortening the current transmission distance, increasing the current intensity acting on the battery cell, and reducing the contact resistance.

[0075] It should be noted that, in both Example 1 and Example 2, the width required to scan the battery cell is scanned in two laser scans, wherein the widths of the first laser scan and the second laser scan may partially overlap. For example, in Example 1, although the width required to scan the battery cell is evenly divided into 2N partitions, the laser scanning may be larger than the width of one partition.

[0076] The technical effects of the present invention are further described below in conjunction with comparative examples and specific embodiments.

[0077] Prior art embodiments

[0078] MBB cells were used, and the existing MBB laser induced sintering method was used. Specifically, the number of probe rows that contacted the cell in a single scan was 1, and the scanning method was to press one side and scan half of the cell on the other side, and the reverse voltage applied was 17 V. The process results are shown in the table.

[0079] Comparative Example 1

[0080] For 0BB bifacial cells, the existing MBB laser induced sintering method is used. Specifically, the number of probe rows that contact the cell in a single scan is 1, and the scanning method is to press one side and scan half of the cell on the other side. The reverse voltage applied is 17V. The process results are shown in the table. It can be seen that the contact resistivity of the cell is as high as 6.3mohm.cm when the existing method is directly used for 0BB bifacial cells. 2 .

[0081] Comparative Example 2

[0082] For the 0BB bifacial battery, the laser induced sintering method of MBB in the prior art is adopted. The difference from Comparative Example 1 is that in order to reduce the contact resistance, the applied reverse voltage is increased to 20V.

[0083] The process results are as follows: the contact resistivity is reduced by 1.8mohm.cm compared with the comparative example 1 above. 2 However, due to the high reverse voltage applied, there is overburning, Uoc will be low, EL will have black edges, and the overall efficiency is low.

[0084] That is to say, the single probe row method of the prior art cannot meet the requirements of applying a suitable reverse voltage and contact resistance.

[0085] Example 3

[0086] For 0BB bifacial cells, the laser induced sintering method of the present application is used. Specifically, the number of probe rows that contact the cell in a single scan is 3, and they are pressed on the cell at equal intervals. The scanning method is that all probe rows are pressed simultaneously, and the scanning width each time is approximately the entire cell width / (3*2), and the applied reverse voltage is 17V. See the table for the process results.

[0087] Example 4

[0088] The number of probe rows that contact the cell in a single scan is 6, which are pressed on the cell at equal intervals. The scanning method is that all probe rows are pressed down at the same time. The scanning width each time is approximately the entire cell width / (6*2), and the applied reverse voltage is 17V. The process results are shown in the table. This solution to reduce the current transmission distance can solve the low efficiency and contact resistance problems of 0BB battery laser sintering.

[0089] Example 5

[0090] The number of probe rows that contact the cell in a single scan is 4 (scanned twice), the format of the cell is 182mm×182mm, when scanning the cell for the first time:

[0091] The first probe row is 27.3mm away from the left edge of the battery cell, the closest distance between the edge of the first probe row in the second direction and the corresponding scanning area is d1=9.1mm, and the farthest distance between the edge of the first probe row in the second direction and the corresponding scanning area is d2=27.3mm; the second probe row is 63.7mm away from the left edge of the battery cell, the corresponding d1=9.1mm for the second probe row, and the corresponding d2=45.5mm for the second probe row; the third probe row is 118.3mm away from the left edge of the battery cell, the corresponding d1=9.1mm for the third probe row, and the corresponding d2=27.3mm for the third probe row; the fourth probe row is 154.7mm away from the left edge of the battery cell, the corresponding d1=9.1mm for the fourth probe row, and the corresponding d2=27.3mm for the third probe row

[0092] After the first laser scan, the probe row is simultaneously offset 18.2mm to the right of the cell along the second direction to scan the cell for the second time: the d1 and d2 corresponding to the first probe row are 9.1mm and 45.5mm respectively; the d1 and d2 corresponding to the second probe row are 9.1mm and 27.3mm respectively; the d1 and d2 corresponding to the third probe row are 9.1mm and 27.3mm respectively, and the d1 and d2 corresponding to the fourth probe row are 9.1mm and 27.3mm respectively. The applied reverse voltage is 17V. The process results are shown in the table. This solution to reduce the current transmission distance can solve the problems of low laser sintering efficiency and contact resistance of 0BB batteries.

[0093] Table 1 Process conditions and process results under different embodiments and comparative examples

[0094]

[0095]

[0096] According to the above comparative examples and embodiments, it can be found that compared with MBB batteries, 0BB batteries have lower efficiency and increased contact resistivity when using the same solution as MBB batteries. Without changing the tooling, the existing laser parameters are optimized and the processing intensity is increased, the contact resistance decreases, the opening voltage becomes lower, and the over-processing cannot solve the low efficiency of 0BB. By reducing the current transmission distance and scanning the laser in equal parts, the contact resistivity is significantly reduced, and the efficiency is on par with that of MBB batteries.

[0097] Compared with a single probe row, multiple rows of probes can maintain uniformity of applied voltage over a larger area of ​​the cell, and the voltage drop at the far end of the probe row is lower than that of a single probe row. Therefore, compared with the method of using a single probe row, this method can reduce the applied reverse voltage, thereby reducing problems caused by excessive voltage, such as black masses appearing at the edge of the cell, sparking on the table (at this time, the cell is placed on a conductive table, and there is a conductive plate on the surface of the conductive table, which acts as a second electrode in contact with the back of the cell), etc.

[0098] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A laser induced sintering processing method, applied to 0BB double-sided electrode batteries, characterized in that: include: The first electrode and the second electrode are used to contact all the fine grid lines on the front side and all the fine grid lines on the back side of the cell respectively, and a reverse voltage is applied to the cell through the first electrode and the second electrode while controlling the laser beam to scan the cell; wherein, All the fine grid lines on the front of the battery cell are arranged in sequence along the first direction, and each of the fine grid lines is continuously extended along the second direction, and the first direction is perpendicular to the second direction; the first electrode includes N strip electrodes arranged at intervals, and each strip electrode is perpendicularly intersected and contacts all the fine grid lines on the front of the battery cell; the width required to be scanned by the battery cell is evenly divided into 2N partitions, and every other partition has one strip electrode, and the strip electrode is located in the partition; When controlling the laser beam to scan the cell: first scan the partition without strip electrodes; then shift all the strip electrodes in the same direction by the size of a partition to the partition that has been scanned, and then laser scan the remaining partitions.

2. The laser induced sintering method according to claim 1, characterized in that: The N strip electrodes of the first electrode are arranged at equal intervals, and the strip electrodes are located in the middle of the partition.

3. The laser induced sintering method according to claim 1, characterized in that: When the format of the battery cell is 182 mm×182 mm, the value range of N is a natural number from 2 to 6; when the format of the battery cell is 210 mm×210 mm, the value range of N is a natural number from 2 to 7.

4. A laser induced sintering processing method, applied to 0BB double-sided electrode battery, characterized in that: include: The first electrode and the second electrode are used to contact all the fine grid lines on the front side and all the fine grid lines on the back side of the cell respectively, and a reverse voltage is applied to the cell through the first electrode and the second electrode while controlling the laser beam to scan the cell; wherein, All the fine grid lines on the front side of the cell are arranged in sequence along the first direction, and each of the fine grid lines is continuously extended along the second direction, and the first direction is perpendicular to the second direction; the first electrode includes a plurality of strip electrodes arranged in sequence at equal or non-equal intervals along the second direction, and each of the strip electrodes is extended along the first direction; When controlling the laser beam to scan the cell, each strip electrode corresponds to a laser scanning area, and the distance between the edge of the strip electrode in the second direction and any position in the corresponding laser scanning area is d, and d is 5 mm to 60 mm; The laser beam is controlled to scan the required scanning width of the battery sheet twice, and after the first scanning is completed, each of the strip electrodes is controlled to deviate a certain distance along the second direction.

5. The laser induced sintering method according to claim 4, characterized in that: After the first scan is completed, each of the strip electrodes is controlled to translate in the same direction or in a non-same direction along the second direction for an equal or different distance, and then a second scan is performed.

6. The laser induced sintering method according to any one of claims 1 to 5, characterized in that: The width of one of the strip electrodes in the second direction ranges from 3 mm to 9 mm.

7. The laser induced sintering method according to any one of claims 1 to 5, characterized in that: The strip electrodes are probe rows, which include a support and a plurality of probes connected to the support, and all the fine grid lines are contacted by the probes.

8. The laser induced sintering method according to claim 7, characterized in that: The plurality of probes of one strip electrode are divided into two probe units separately arranged along the second direction, and the two probe units are staggered in the second direction.

9. The laser induced sintering method according to any one of claims 1 to 5, characterized in that: During scanning, a laser beam is used to scan successively, and after scanning one partition, the next partition to be scanned is scanned; or, several laser beams are used, each laser beam corresponds to a partition to be scanned, and scanned simultaneously.

10. A device for completing the laser induced sintering method according to any one of claims 1 to 9, characterized in that: include: A processing table, used for carrying the battery sheet; a first electrode and a second electrode; Laser scanning device; The moving mechanism is used for moving the processing table and / or the first electrode.

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