Electric field enhanced light injection method and device and battery piece production method and system

Abstract

The invention provides an electric field enhanced light injection method and device and a battery piece production method and system.The electric field enhanced light injection method comprises the steps that an electric field is applied to a battery piece precursor, the direction of the electric field is in the built-in electric field direction of the battery piece precursor, and the battery piece precursor comprises an N-type doping layer, a P-type doping layer and electrode slurry which are sequentially stacked; meanwhile, the electrode slurry of the battery piece precursor is illuminated, so that by applying an electric field in the direction of the built-in electric field, when light is injected into the battery piece precursor, instantaneous photo-generated current can be generated under the enhancement effect of the electric field, the photo-generated current is transmitted in the electrode slurry to generate instantaneous high temperature, and then auxiliary sintering is achieved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of solar cell panels, and in particular to an electric field enhanced light injection method and device, and a cell production method and system. Background Art

[0002] The production process of solar cells involves many processes. For example, after printing metal paste on the cell silicon wafer, a high-temperature sintering process is required to remove the organic solvent in the paste, melt the glass powder, condense the metal powder to form metallized grid lines, and make the grid lines form good contact with the silicon wafer surface. Different sintering processes are required to achieve the best ohmic contact effect for different metal pastes and different contact effect requirements.

[0003] The light injection process is a process that uses light to irradiate the cell. The principle is that photons hit the film layer and the surface layer of the cell, thereby exciting the hydrogen ions in the silicon nitride to enter the surface of the cell. The hydrogen ions replace the impurity atoms and broken bonds on the surface of the silicon wafer, which play a role in passivating the cell defects, thereby increasing the open circuit voltage of the cell and then improving the conversion efficiency.

[0004] Laser-assisted sintering is usually performed after the light injection process to enhance the fill factor of the cell. Summary of the invention

[0005] On the one hand, an embodiment of the present disclosure provides an electric field enhanced light injection method, comprising: applying an electric field to a cell precursor, wherein the direction of the electric field is along the direction of a built-in electric field of the cell precursor, wherein the cell precursor comprises an N-type doped layer, a P-type doped layer and an electrode slurry stacked in sequence; and at the same time, irradiating the electrode slurry of the cell precursor with light.

[0006] With such an arrangement, by applying an electric field along the direction of the built-in electric field, when light is injected into the interior of the cell precursor, an instantaneous photocurrent can be generated due to the enhanced effect of the electric field. This photocurrent is transmitted in the electrode slurry to generate an instantaneous high temperature, thereby achieving auxiliary sintering. Moreover, the high temperature is only generated in the ohmic contact area between the electrode slurry and the cell material, which can avoid heat loss and enhance the sintering effect.

[0007] The electric field enhanced light injection method can enhance the fill factor and reduce light-induced attenuation. The electric field enhanced light injection method has a smooth sintering process, and compared with laser sintering and other methods, there is no need to worry about the deviation of laser alignment and probe alignment. The electric field enhanced light injection method can enhance the auxiliary sintering effect; the sintering effect is uniform; avoid damage to electrodes or semiconductor materials; and improve battery efficiency and quality.

[0008] In some embodiments, the intensity of the electric field ranges from 50 KV / m to 200 KV / m; the intensity of the light ranges from 10 KW / m 2Up to 100KW / m 2 ; The process temperature ranges from 300℃ to 600℃.

[0009] Such a setting can generate photogenerated carriers of sufficient density, control the amount of additional heat that can be generated, and the intensity of the electric field can assist in controlling the magnitude of the instantaneous current and the duration of the current; the process temperature can affect the sintering effect of the electrode slurry and ensure good sintering.

[0010] In some embodiments, the waveform of the electric field is a square wave; the cycle time of the electric field ranges from 10 ms to 100 ms, and the forward opening time of the electric field is 30% to 60% of the electric field cycle.

[0011] Such an arrangement is conducive to a faster change of the electric field, thereby achieving a better effect of instantaneous current sintering of silicon wafers.

[0012] In some embodiments, the step of applying an electric field includes a first step of applying an electric field and a second step of applying an electric field, and the intensity of the electric field applied in the second step is 50% to 100% of the intensity of the electric field applied in the first step; the step of irradiating light includes a first step of irradiating light and a second step of irradiating light, and the intensity of the second step of irradiating light is 50% to 90% of the intensity of the first step.

[0013] With this arrangement, electric field enhanced light injection is performed in steps, and the respective intensities of light and electric field are gradually reduced to supplement the auxiliary contact.

[0014] On the other hand, the embodiments of the present disclosure provide a method for producing a battery cell, which includes: sintering a battery cell precursor, the battery cell precursor after sintering includes an electrode slurry, a P-type doping layer, an N-type doping layer and a back electrode stacked in sequence, the electrode slurry is an electrode slurry in an under-fired state; and the steps of the aforementioned electric field enhanced light injection method.

[0015] Through the steps of the electric field enhanced light injection method, electrode slurry sintering can be achieved without laser sintering, and the process flow of the battery cell production method is relatively simple.

[0016] On the other hand, an embodiment of the present disclosure provides an electric field enhanced light injection device, which includes: an electric field generating device, configured to: apply an electric field to a cell precursor, the direction of the electric field is along the direction of the built-in electric field of the cell precursor; and a light-emitting device, configured to: irradiate the electrode slurry of the cell precursor while applying the electric field.

[0017] The electric field enhanced light injection device according to the embodiment of the present disclosure can be used to perform the steps of the electric field enhanced light injection method.

[0018] In some embodiments, the electric field enhanced light injection device further includes a heating device for heating the cell precursor; the electric field generating device is further configured such that the waveform of the electric field is a square wave.

[0019] With such an arrangement, heating can be performed and a square wave electric field can be realized.

[0020] In some embodiments, the electric field enhanced light injection device also includes a conveying device, which is used to convey the cell precursor; the electric field generating device includes a first electric field generator and a second electric field generator arranged in sequence along the conveying route of the conveying device; the light-emitting device includes a first light emitter and a second light emitter arranged in sequence along the conveying route of the conveying device, wherein the first light emitter corresponds to the first electric field generator, and the second light emitter corresponds to the second electric field generator.

[0021] Such an arrangement can realize an assembly line production mode, carry out each step continuously, and facilitate connection with external equipment.

[0022] In yet another aspect, an embodiment of the present disclosure provides a cell production system, the cell production system comprising: a sintering furnace; and the aforementioned electric field enhanced light injection device.

[0023] The cell production system of the embodiment of the present disclosure can be used to manufacture cells. The cell production system uses fewer devices, avoids the need to install laser sintering equipment, reduces occupied space, and reduces costs.

[0024] On the other hand, the embodiments of the present disclosure provide a cell, which is obtained according to the steps of the aforementioned electric field enhanced light injection method. The cell can be obtained according to the steps of the aforementioned cell production method. The cell can be manufactured using the aforementioned electric field enhanced light injection device. The cell can be manufactured using the aforementioned cell production system.

[0025] The battery cell is sintered uniformly and has low manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of a battery cell in an embodiment of the present disclosure; Figure 2 is a schematic flow chart of a method for producing a battery cell in an embodiment of the present disclosure; Figure 3 is a schematic waveform diagram of the electric field in the embodiment of the present disclosure; Figure 4 is a schematic structural block diagram of a battery cell production system in an embodiment of the present disclosure; Figure 5 It is a schematic diagram of the structure of the electric field enhanced light injection device in the embodiment of the present disclosure; Figure 6 It is the temperature curve diagram of the embodiment; Figure 7 This is the temperature curve of the comparison group.

[0027] Reference numerals: 1, electric field generating device; 11, first electric field generator; 12, second electric field generator; 2, light emitting device; 21, first light emitter; 22, second light emitter; 3, heating device; 4, conveying device; 5, cooling device; 100. Cell production system; 110. Sintering furnace; 120. Electric field enhanced light injection equipment; 200. Cell; 201. N-type doping layer; 202. P-type doping layer; 203. Front passivation layer; 204. Front silicon nitride layer; 205. Tunneling layer; 206. Conductive layer; 207. Back silicon nitride layer; 208. Back electrode; 209. Front electrode. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present disclosure more obvious and understandable, the specific implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the embodiments of the present disclosure. However, the embodiments of the present disclosure can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the embodiments of the present disclosure, so the embodiments of the present disclosure are not limited by the specific examples of the embodiments disclosed below.

[0029] In the description of the embodiments of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "perpendicular", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present disclosure.

[0030] In the embodiments of the present disclosure, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0031] In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. Exemplarily, the first electric field generator may also be referred to as the second electric field generator, and the second electric field generator may also be referred to as the first electric field generator. In the description of the embodiments of the present disclosure, "multiple" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0032] In the embodiments of the present disclosure, unless otherwise clearly specified and limited, the terms "connected", "connected", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a flexible connection, or a rigid connection along at least one direction; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or directly connected with the presence of an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly limited. The terms "installed", "set", "fixed", etc. can be broadly understood as connection. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0033] As used herein, the terms "layer" and "region" refer to a portion of a material that includes an area with a certain thickness. A layer can extend horizontally, vertically and / or along a tapered surface. A layer can be an area of ​​a uniform or non-uniform continuous structure, and its thickness perpendicular to the extension direction may not be greater than the thickness of the continuous structure. A layer can include multiple layers, which can be stacked layers or multiple layers extending discretely. The shapes of various regions and layers in the drawings and their relative sizes and positional relationships are only exemplary, and may actually deviate due to manufacturing tolerances or technical limitations, and the design can be adjusted according to actual needs.

[0034] refer to Figure 1 , Figure 1 The cell of the embodiment of the present disclosure is shown. The cell 200 may be a tunneling oxide passivated contact (TOPCon) solar cell. The front of the TOPCon cell is different from the "passivated emitter and rear contact (PERC) cell". The TOPCon cell uses a boron diffusion process to form a PN junction. The boron-diffused PN junction has many differences compared to the phosphorus-diffused PN junction, mainly in the following two points: 1. The surface carrier concentration of the diffusion layer formed by boron diffusion is lower; 2. The junction depth of the boron-diffused is deeper.

[0035] Compared with PERC cells, TOPCon cells have different diffusion junction depths and surface concentrations, which put forward different requirements for the sintering process. Compared with PERC cells, TOPCon cells require more metal-silicon contact area to improve the current collection capability. In order to achieve this goal, the sintering process of TOPCon cells needs to form a "wedge nail" structure. The metal slurry is ablated into the surface of the silicon wafer to form a "wedge nail". This structure greatly increases the surface contact between the metal and the silicon wafer, reduces the contact resistance, and increases the ability to collect current. In terms of electrical performance, the series resistance of the battery decreases and the fill factor increases. During the process debugging of TOPCon cells, a phenomenon was found: the light injection process has an enhancing effect on the metal contact on the front of TOPCon. It can be understood that under the action of light and high temperature, the cell is sintered again, which improves the fill factor. However, starting from the light injection process, whether adjusting the temperature or light, the improvement of the re-sintering is relatively limited. After the light injection process, laser sintering is also required to complete the manufacturing of the cell.

[0036] Exemplarily, the cell 200 includes a back silicon nitride layer 207, a conductive layer 206, a tunneling layer 205, an N-type doped layer 201, a P-type doped layer 202, a front passivation layer 203, and a front silicon nitride layer 204 stacked in sequence. Further, the back electrode 208 of the cell 200 is electrically connected to the conductive layer 206, and the front electrode 209 is in contact with the P-type doped layer 202.

[0037] refer to Figure 2 The present disclosure provides a cell production method. The cell production method 1000 includes step S1100: sintering a cell precursor, wherein the sintered cell precursor includes an electrode slurry, a P-type doping layer 202, an N-type doping layer 201 and a back electrode 208 stacked in sequence, and the electrode slurry is an under-fired electrode slurry.

[0038] Before step S1100, a step of printing electrode paste on both sides of the laminated structure may also be included, wherein both the back paste and the front paste may be printed in a patterned manner and used to form metal grid lines. The material of the back paste is different from the material of the front paste. After the sintering step, the back electrode 208 is obtained based on the back paste, and the front paste is an under-fired electrode paste. Exemplarily, the peak temperature of the front side of the cell precursor does not exceed 760°C, such as 750°C or 755°C. The material of the back paste and the material of the front paste can be set according to the process temperature to ensure that the back paste is sintered and the front paste is under-fired. Exemplarily, the temperature of the front side and the back side of the cell precursor can be different, and the temperature of the front side and the temperature of the back side can respectively ensure the sintering effect of the front side and the back side. In addition, the temperature can be controlled to avoid over-burning.

[0039] The cell production method 1000 also includes the step of electric field enhanced light injection method S1200. Through the step of electric field enhanced light injection method S1200, electrode slurry sintering can be achieved without laser sintering, and the process flow of the cell production method 1000 is relatively small.

[0040] Specifically, the electric field enhanced light injection method S1200 provided in the embodiment of the present disclosure includes step S1210 and step S1220.

[0041] Step S1210, applying an electric field to the cell precursor, the direction of the electric field is along the direction of the built-in electric field of the cell precursor. The built-in electric field of the cell precursor points from the N-type doped layer 201 to the P-type doped layer 202, and the electrode slurry is stacked on the side of the P-type doped layer 202 facing away from the N-type doped layer 201.

[0042] Step S1220, irradiate the electrode slurry of the cell precursor. Optionally, the irradiation time can be longer. At least for a period of time, step S1210 and step S1220 are performed simultaneously. Under the enhanced effect of the electric field along the direction of the built-in electric field, an instantaneous photocurrent can be generated when light is injected into the cell precursor. This photocurrent is transmitted in the electrode slurry to generate an instantaneous high temperature, thereby achieving auxiliary sintering. Moreover, the high temperature is only generated in the ohmic contact area between the electrode slurry and the battery material, which can avoid heat loss and enhance the sintering effect.

[0043] The electric field enhanced light injection method S1200 of the disclosed embodiment can enhance the fill factor and reduce light-induced attenuation. The electric field enhanced light injection method S1200 has a smooth sintering process, and compared with laser sintering and other methods, there is no need to worry about the deviation of the laser alignment and the deviation of the probe alignment. The electric field enhanced light injection method S1200 can enhance the auxiliary sintering effect; the sintering effect is uniform; avoid damage to the electrode or semiconductor material; and improve the efficiency and quality of the battery.

[0044] The illumination can be performed using, for example, LED light, and the entire cell precursor surface can be illuminated, without having to accurately locate the light in a small area as with lasers. Optionally, the wavelength of the light is in the range of 400nm to 1000nm, for example, the wavelength of the light is 500nm, 600nm, 700nm, 800nm ​​or 900nm.

[0045] For example, the intensity of the light is in the range of 10KW / m 2 Up to 100KW / m 2 , can generate sufficient density of photogenerated carriers to control the amount of additional heat that can be generated. Among them, 1KW / m 2 It may also be called 1 sun, and the intensity of the light may then be 15 suns, 35 suns, 55 suns, 75 suns or 95 suns.

[0046] The intensity of the electric field can range from 50KV / m to 200KV / m. The intensity of the electric field assists in controlling the magnitude of the instantaneous current and the duration of the current. Optionally, the intensity of the electric field can be 70KV / m, 100KV / m, 130KV / m, 150KV / m or 180KV / m. The process temperature can range from 300°C to 600°C, such as 480°C, 580°C. The process temperature can affect the sintering effect of the electrode slurry and ensure good sintering.

[0047] refer to Figure 3 , the waveform of the electric field is a square wave, and the electric field strength is, for example, 80KV / m. The cycle time of the electric field ranges from 10ms to 100ms, and the frequency of the corresponding electric field is from 10Hz to 100Hz. The square wave is conducive to faster changes in the electric field, which can then achieve a better effect of instantaneous current sintering of silicon wafers. Optionally, the cycle time of the electric field is 20ms, 30ms, 40ms, 50ms, 60ms, 70ms, 80ms or 90ms. In other embodiments, the cycle time of the electric field may also be less than 10ms, such as 9ms, 8ms, 7ms or 6ms.

[0048] The forward opening time of the electric field is 30% to 60% of the electric field cycle, for example, 40% or 50%. Exemplarily, the time when the cell precursor is subjected to the forward electric field is 0.2s to 1.5s. When the cell precursor moves along the assembly line, the electric field action time = (length of the electric field emission device × electric field opening time) / (transmission speed × electric field cycle time). The time when the cell precursor is subjected to the forward electric field can be 0.4s, 0.6s, 0.8s, 1.0s, 1.2s or 1.4s. Reference Figure 3 , the reverse electric field does not need to be set, and the electric field strength during the square wave interval of the forward electric field can be 0KV / m.

[0049] The step of applying an electric field may include a first step of applying an electric field and a second step of applying an electric field, and the step of irradiating light may include a first step of irradiating light and a second step of irradiating light. Preferably, the intensity of the electric field applied in the second step is 50% to 100% of the intensity of the electric field applied in the first step, for example, 60%, 70%, 80% or 90%; the intensity of the illumination in the second step is 50% to 90% of the intensity of the illumination in the first step, for example, 65%, 75% or 85%. Electric field enhanced light injection is performed in steps, and the intensities of light and electric field are gradually reduced, to supplement the auxiliary contact.

[0050] Exemplarily, the electric field enhanced light injection method S1200 also includes step S1230: heating the cell precursor. The heating can be performed before the light injection and also during the light injection process. The process temperature of the light injection process may be higher than the preheating temperature. The process temperature of the first electric field enhanced light injection step may be different from the process temperature of the second electric field enhanced light injection step. For example, the temperature of the later electric field enhanced light injection step may be lower. The electric field enhanced light injection method S1200 also includes step S1240: cooling the cell 200 after the electrode slurry is sintered to form the front electrode 209. After step S1240, the temperature of the surface of the cell 200 may drop to below 100°C, and then the next process may be entered. In the embodiments of the present disclosure, the structure obtained in each process step may be referred to as a precursor used in the next process step.

[0051] The electric field enhanced light injection method S1200 of the embodiment of the present disclosure may also be applied to other types of semiconductor contact processes.

[0052] refer to Figure 4 The embodiment of the present disclosure provides a cell production system 100, which includes a sintering furnace 110 and an electric field enhancement light injection device 120. The sintering furnace 110 can be used to perform step S1100, and the electric field enhancement light injection device 120 can be used to perform the steps of the electric field enhancement light injection method S1200. The cell production system 100 of the embodiment of the present disclosure can be used to manufacture cells 200. The cell production system 100 uses less equipment, avoids the need for laser sintering equipment, reduces occupied space, and reduces costs.

[0053] Combination Figure 5 As shown, the electric field enhancement light injection device 120 provided in the embodiment of the present disclosure may include an electric field generating device 1 and a light emitting device 2. After the cell precursor enters the electric field enhancement light injection device 120, it can be acted upon by the electric field generating device 1 and the light emitting device 2 simultaneously, and then can be formed into a cell 200.

[0054] The electric field generating device 1 is configured to apply an electric field to the cell precursor, and the direction of the electric field is along the direction of the built-in electric field of the cell precursor. Exemplarily, the under-burned electrode material in the cell precursor is located on the upper side along the Y-axis direction, and the direction of the built-in electric field in the cell precursor can be from bottom to top, and then the electric field direction of the electric field generating device 1 can be configured to be from bottom to top. The electric field generating device 1 can also be configured such that the waveform of the electric field is a square wave.

[0055] The light emitting device 2 is configured to illuminate the electrode paste of the cell precursor, for example, illuminate the cell precursor from above. Further, the light emitting device 2 can illuminate the electrode paste of the cell precursor while the electric field generating device 1 is applying the electric field.

[0056] According to the placement of the cell precursor in the production line, the electric field enhancement light injection device 120 can be configured to be used to perform the steps of the electric field enhancement light injection method S1200, and then the electrode slurry can be sintered into the front electrode 209. The electric field enhancement light injection device 120 can be used to manufacture the cell 200.

[0057] Exemplarily, the light emitting device 2 may include a plurality of LED lamps to realize a surface light source irradiating a cell precursor, and the area of ​​the surface light source may be larger than the area of ​​a cell precursor. The electric field generating device 1 may include at least one electric field generator, which may be located in the surface light source, for example, in the middle of the surface light source.

[0058] In some embodiments, the electric field enhanced light injection device 120 further includes a heating device 3, which is used to heat the cell precursor. Figure 5 As shown, the heating device 3 at least includes a heating section for heating at the light emitting device 2 to ensure the process temperature of the cell precursor. The heating section can be arranged around the surface light source. Furthermore, a corresponding heating section is arranged at each light emitter.

[0059] The electric field enhanced light injection device 120 also includes a conveyor 4, which is used to convey the cell precursor. The conveyor 4 can connect the equipment of the previous and next processes so that the cell precursor or the cell 200 can be continuously conveyed, and can realize the assembly line production mode, continuously perform various steps, and facilitate connection with external equipment such as the sintering furnace 110. The conveyor belt speed of the conveyor 4 can be 1m / s to 5m / s. Exemplarily, the heating device 3 includes a preheating section upstream of the light-emitting device 2, and the preheating section can increase the temperature of the cell precursor to 300°C to 500°C, such as 350°C, 400°C or 450°C.

[0060] The electric field generating device 1 may include a first electric field generator 11 and a second electric field generator 12 sequentially arranged along the transmission route of the transmission device 4. The transmission route of the transmission device 4 may be a straight line along the Y-axis direction, or may be other routes. Furthermore, the light-emitting device 2 may include a first light emitter 21 and a second light emitter 22 sequentially arranged along the transmission route of the transmission device 4, wherein the first light emitter 21 corresponds to the first electric field generator 11, and the second light emitter 22 corresponds to the second electric field generator 12. The electric field generating device 1 may include more electric field generators, and the light-emitting device 2 may also include more light emitters. The electric field intensity of each electric field generator may be configured as required, and the illumination intensity of each light emitter may be configured as required, for example, along the transmission route, the electric field intensity and the illumination intensity each decrease in sequence.

[0061] Optionally, by coordinating the conveying speed of the conveying device 4, the length of the electric field generator can be set to 20 mm to 200 mm, which ensures the effective working time and avoids overburning. The various parameters including the length can be configured according to the aforementioned formula for calculating the electric field action time, for example, the length of the electric field generator is 50 mm, 100 mm or 150 mm.

[0062] Exemplarily, the electric field enhanced light injection device 120 may further include a cooling device 5, which is located downstream of the electric field generating device 1 and the light emitting device 2 along the conveying route of the conveying device 4, and is used to cool the battery cell 200. The cooling method of the cooling device 5 may include air cooling and water cooling.

[0063] The cell 200 of the embodiment of the present disclosure can be obtained according to the steps of the aforementioned electric field enhanced light injection method S1200 and the steps of the aforementioned cell production method 1000; the cell 200 can be manufactured using the aforementioned electric field enhanced light injection device 120 and the cell production system 100. The cell 200 is sintered uniformly and has low manufacturing cost.

[0064] Example 1 This embodiment provides a method for producing a cell, which is used to manufacture a 182mm×182mm N-type TOPCon process cell 200, wherein the material of the front passivation layer 203 is aluminum oxide, the PN junction is a PN junction formed by boron diffusion with a junction depth of about 1.8μm, the tunneling layer 205 is an oxide layer, and the conductive layer 206 is a 150nm thick N+ type doped polysilicon layer. Specifically, after obtaining the cell precursor after the coating process, the following steps are performed.

[0065] The heating parameters and cooling parameters of each position of the sintering furnace 110 are adjusted to achieve a peak temperature of about 730°C on the front side of the cell precursor and a peak temperature of about 715°C on the back side. Figure 6 The temperature curve of the cell precursor in the sintering furnace 110 is shown. After sintering, the contact resistance of the cell precursor is tested. The back contact resistance is about 1Ω, reaching the normal contact resistance; while the front contact resistance test fails, indicating that the front has not completed effective sintering.

[0066] Debug the electric field enhanced light injection device 120. Specifically, the temperature of the preheating section in the heating device 3 can be adjusted, and the surface temperature of the cell precursor after preheating reaches 450°C; other functional sections of the heating device 3 are also adjusted, and the parameters of the first light emitter 21, the second light emitter 22, the first electric field generator 11, and the second electric field generator 12 are adjusted.

[0067] The illumination current of the first light emitter 21 can be adjusted to 10A to achieve an illumination intensity of 50KW / m 2The temperature of the light injection zone is set to 550°C, and the electric field of the first electric field generator 11 is a square wave with a frequency of 100 Hz. Figure 3 As shown, the electric field strength is 80KV / m.

[0068] The illumination current of the second light emitter 22 can be adjusted to 6A so that the illumination intensity is 30KW / m 2 The temperature of the light injection zone is set to 500° C., the electric field of the second electric field generator 12 is a square wave with a frequency of 120 Hz and an electric field strength of 80 KV / m.

[0069] The cooling device 5 is configured to reduce the temperature of the battery cell 200 to below 100°C.

[0070] Example 2 Compared with the method of Example 1, the method for producing a cell provided in this embodiment is configured such that the electric field strength of the first electric field generator 11 is 100 KV / m, and the electric field strength of the second electric field generator 12 is 150 KV / m. The remaining steps of this embodiment are the same as the corresponding steps of Example 1, including the steps of preparing a cell precursor of an N-type TOPCon process with a size of 182 mm×182 mm, performing back sintering and front under-sintering, and cooling.

[0071] Example 3 Compared with the method in Example 1, the method for producing a cell provided in this embodiment can configure the illumination current of the first light emitter 21 to be 12A, so that the illumination intensity is 60KW / m 2 The illumination current of the second light emitter 22 can be adjusted to 8A so that the illumination intensity is 40KW / m 2 The remaining steps of this embodiment may also be the same as the corresponding steps of Embodiment 1.

[0072] Comparison group like Figure 7 As shown, in the comparison group, a conventional tunnel structure sintering furnace was used, and the highest sintering temperature reached 767° C. to sinter both the front electrode slurry and the back electrode slurry of the cell precursor to obtain the cell of the comparison group.

[0073] The products obtained in Example 1, the products obtained in Example 2, the products obtained in Example 3 and the products of the control group are compared in the following table: Table 1

[0074] Among them, Uoc refers to the open circuit voltage, and the measurement unit is volts; Isc refers to the short circuit current, and the measurement unit is amperes; Rser is the calculated series resistance, and the unit is ohms; Rsh is the calculated parallel resistance, and the unit is ohms; FF is the calculated fill factor, which is a percentage value; Eta is the calculated conversion efficiency, which is a percentage value; Irev2 is the leakage value, and the measurement unit is amperes.

[0075] It can be seen that the filling factor of each embodiment is higher than that of the comparison group, and the conversion efficiency of each embodiment is higher than that of the comparison group.

[0076] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The above-mentioned various forms of processes can be used, and steps can be reordered, added or deleted. The steps recorded in the embodiments of the present disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired results of the technical solutions provided by the embodiments of the present disclosure can be achieved, and this document does not limit them here.

[0078] The above-mentioned embodiments only express several implementation methods of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the disclosed patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the disclosed patent shall be subject to the attached claims.

Claims

1. Electric field enhanced light injection method, characterized in that: include: Applying an electric field to a cell precursor, wherein the direction of the electric field is along the direction of the built-in electric field of the cell precursor, wherein the cell precursor comprises an N-type doping layer, a P-type doping layer and an electrode slurry stacked in sequence; At the same time, the electrode slurry of the cell precursor is irradiated with light.

2. The electric field enhanced light injection method according to claim 1, wherein: The intensity of the electric field ranges from 50KV / m to 200KV / m; the intensity of the light ranges from 10KW / m 2 Up to 100KW / m 2 ; The process temperature ranges from 300℃ to 600℃.

3. The electric field enhanced light injection method according to claim 1, wherein: The waveform of the electric field is a square wave; the cycle time range of the electric field is 10ms to 100ms, and the forward opening time of the electric field is 30% to 60% of the electric field cycle.

4. The electric field enhanced light injection method according to claim 1, wherein: The step of applying an electric field includes a first step of applying an electric field and a second step of applying an electric field, wherein the intensity of the electric field applied in the second step is 50% to 100% of the intensity of the electric field applied in the first step; The illumination step includes a first illumination step and a second illumination step, and the intensity of the second illumination step is 50% to 90% of the intensity of the first illumination step.

5. A method for producing a battery cell, characterized in that: include: Sintering the cell precursor, wherein the sintered cell precursor comprises an electrode slurry, a P-type doping layer, an N-type doping layer and a back electrode stacked in sequence, wherein the electrode slurry is an electrode slurry in an under-fired state; and The steps of the electric field enhanced light injection method as claimed in any one of claims 1 to 4.

6. Electric field enhanced light injection device, characterized in that include: An electric field generating device is configured to: apply an electric field to the cell precursor, wherein the direction of the electric field is along the direction of the built-in electric field of the cell precursor; and The light emitting device is configured to illuminate the electrode paste of the cell precursor simultaneously with the step of applying the electric field.

7. The electric field enhanced light injection device according to claim 6, wherein: It also includes a heating device, which is used to heat the battery cell precursor; the electric field generating device is also configured so that the waveform of the electric field is a square wave.

8. The electric field enhanced light injection device according to claim 6, wherein: It also includes a conveying device, the conveying device is used to convey the battery sheet precursor; The electric field generating device comprises a first electric field generator and a second electric field generator which are sequentially arranged along a transmission route of the transmission device; The light emitting device comprises a first light emitter and a second light emitter which are sequentially arranged along a conveying route of the conveying device, wherein the first light emitter corresponds to the first electric field generator, and the second light emitter corresponds to the second electric field generator.

9. A battery cell production system, characterized in that: include: Sintering furnace; as well as An electric field enhanced light injection device as claimed in any one of claims 6 to 8.

10. A battery cell, characterized in that: The method is obtained according to the steps of the electric field enhanced light injection method as described in any one of claims 1 to 4, obtained according to the steps of the battery cell production method as described in claim 5, manufactured using the electric field enhanced light injection equipment as described in any one of claims 6 to 8, or manufactured using the battery cell production system as described in claim 9.

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