IBC battery piece, diffusion method thereof and quartz boat
By setting mask areas and diffusion areas at different distances between the back and front of the IBC cell, the design of the quartz boat achieves diffusion and achieves different resistances on both sides of the same element, the production cost and process complexity problems caused by different doping requirements in the production process of IBC cells in the prior art are solved, and the battery efficiency is maintained and the production process is simplified.
Patent Information
- Application Number
- CN202411647041.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-18
- Publication Date
- 2025-02-28
AI Technical Summary
During the production process, existing IBC batteries need to be doped by distributing masks due to different front and back doping requirements during the production process, which increases production cost and process complexity.
By setting mask areas and diffusion areas at different distances between the back and front of the IBC cell, the IBC cells are arranged in the diffusion furnace at a specific spacing using the design of the quartz boat, so that the primary diffusion can be achieved to achieve different resistances on both sides of the same element.
A double-sided diffusion of IBC battery cells that reduce production processes and reduce production costs without damaging battery efficiency.
Smart Images
Figure CN119545954A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field related to batteries, and in particular to an IBC battery sheet and a diffusion method thereof, and a quartz boat. Background Art
[0002] The IBC (Interdigitated back contact) battery structure designs the battery PN junction on the back of the battery cell. The absence of a grid line on the front can greatly increase the battery current, but it increases the lateral transmission of the battery. The carriers need a longer transmission path to be effectively collected. In order to ensure the effective transmission of the battery, FSF (Front Surface Field)-IBC batteries and FFE (Front Floating Emitter)-IBC batteries have been developed. However, both front surface field and front surface floating junction emitter batteries have a same-element diffusion on the front and back sides. FSF-IBC batteries require phosphorus diffusion on both the front and back sides, while front floating emitters require boron diffusion on both the front and back sides.
[0003] Since the front and back sides have completely different functions, the front phosphorus expansion of the FSF-IBC battery plays a field passivation role and cannot be doped too heavily, while the back side of the battery needs to be heavily doped to improve contact; the front floating emitter of the FFE-IBC battery mainly plays a lateral transmission role, and if it is doped too heavily, it will aggravate the recombination, but the back side needs to prepare a PN junction, and the contact resistance must also be considered, so heavy doping is usually used;
[0004] Therefore, due to the different doping on the front and back sides, the industry needs to dope the front and back sides through a distributed mask, which will greatly increase the IBC battery process and product costs; there is also a method in the prior art to directly perform a diffusion to keep the square resistance of the front and back sides the same. Although this simplifies the process flow, it also leads to an increase in front recombination and a great loss of battery efficiency. Summary of the invention
[0005] The object of the present invention is to provide an IBC cell sheet and a diffusion method thereof, and a quartz boat, so as to reduce the production process of the IBC cell and lower the production cost while ensuring the efficiency of the IBC cell sheet.
[0006] In order to solve the above technical problems, the present invention provides an IBC cell sheet and a diffusion method thereof, and a quartz boat.
[0007] The IBC cell diffusion method of the present invention comprises:
[0008] Arrange multiple battery groups at intervals, each battery group includes two IBC battery sheets arranged opposite to each other at a first distance, and the distance between two adjacent battery groups is a second distance, and the second distance is greater than the first distance;
[0009] Diffusion of IBC cells.
[0010] Furthermore, the first spacing is 2-3.5 mm, and the second spacing is 4-7 mm.
[0011] Further, the diffusing the IBC cell sheet includes:
[0012] In the diffusion stage, the IBC cell is placed in a diffusion furnace, and oxygen, pure nitrogen, and nitrogen carrying a phosphorus source or a boron source are introduced at a first set pressure. The temperature of the diffusion furnace is the first set temperature, and the diffusion is performed for 4-6 minutes.
[0013] In the advancement stage, the temperature of the diffusion furnace is raised to the second set temperature, and pure nitrogen and oxygen are introduced for 20-30 minutes.
[0014] Furthermore, the first set temperature is 750-850°C, the first set pressure is 200-300mbar, and at the first set temperature, the flow rate of nitrogen carrying a phosphorus source or a boron source is 100-150sccm, the flow rate of oxygen is 100-450sccm, and the flow rate of pure nitrogen is 2000-4000sccm.
[0015] Furthermore, the second set temperature is 850-910° C., the flow rate of the introduced pure nitrogen is 2000-4000 sccm, and the flow rate of the introduced oxygen is 8000-15000 sccm.
[0016] Furthermore, the phosphorus source is phosphorus oxychloride.
[0017] Furthermore, the molar percentage of the phosphorus source is 2%-5%.
[0018] Furthermore, a plurality of battery packs are placed on a quartz boat for diffusion.
[0019] Furthermore, a mask area and a diffusion area are prepared on the back side of the IBC cell, and the mask area is used to isolate diffusion.
[0020] Furthermore, there are a plurality of the mask regions and the diffusion regions, and the mask regions and the diffusion regions are arranged alternately and spaced one by one.
[0021] The present invention also provides an IBC battery, which is manufactured by the IBC battery sheet diffusion method described in any one of the above technical solutions.
[0022] The present invention also provides a quartz boat for implementing the IBC battery cell diffusion method described in any one of the above technical solutions, comprising a boat body and a plurality of adjacent boat tooth groups arranged on the boat body, each group of the boat tooth groups comprising two adjacent boat teeth, the distance between the two boat teeth in each group of the boat tooth groups being a first spacing, and being used for arranging two IBC battery cells arranged with their front sides relatively spaced apart, the distance between two adjacent boat tooth groups being a second spacing, and the second spacing being greater than the first spacing.
[0023] Furthermore, the first spacing is 2-3.5 mm, and the second spacing is 4-7 mm.
[0024] Compared with the prior art, the present invention has at least the following beneficial effects:
[0025] By making the distance between the back sides of the IBC battery cells different from the distance between the front sides, different square resistances of the same element on both sides can be achieved through one diffusion, thereby achieving one-time double-sided diffusion of the IBC battery without damaging the battery efficiency and without increasing the process steps, reducing the production process of the IBC battery and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 A flow chart of an embodiment of the IBC cell diffusion method of the present invention;
[0027] Figure 2 It is a structural schematic diagram of the quartz boat of the present invention;
[0028] Figure 3 It is a partial schematic diagram of the placement state of the IBC cell and the quartz boat when the IBC cell diffusion method of the present invention is used for diffusion;
[0029] Figure 4 It is a schematic diagram of the back side of an IBC cell processed by the IBC cell diffusion method of the present invention.
[0030] Reference numerals: 10, boat body; 20, boat teeth. DETAILED DESCRIPTION
[0031] The IBC cell sheet and its diffusion method and quartz boat of the present invention will be described below in conjunction with schematic diagrams, wherein preferred embodiments of the present invention are shown. It should be understood that those skilled in the art can modify the present invention described herein and still achieve the beneficial effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art and not as a limitation of the present invention.
[0032] The serial numbers of the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings). In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.
[0033] In the present invention, 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.
[0034] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are in very simplified form and in non-precise proportions, and are only used to facilitate and clearly assist in illustrating the purpose of the embodiments of the present invention.
[0035] The inventors have found that the one-time diffusion method in the prior art is as follows:
[0036] Arrange the IBC cells at equal intervals and place them in a diffusion furnace;
[0037] In the diffusion stage, under the environment of 100-200 mbar (millibar, air pressure unit) pressure and 750-850°C temperature, the flow rate of nitrogen gas carrying phosphorus source is 200-350 sccm (volume flow unit, standard cubic centimeter per minute, i.e. standard milliliter per minute), the flow rate of oxygen gas is 500-1000 sccm, the flow rate of pure nitrogen gas is 2000-4000 sccm, and the diffusion is carried out for 4-6 minutes;
[0038] During the advancement stage, the temperature is raised to 880-940°C, the flow rate of pure nitrogen introduced is 2000-4000sccm, the flow rate of oxygen introduced is 8000-15000sccm, and the advancement is carried out for 30-40 minutes.
[0039] The front and back square resistances of the final IBC cell are consistent, ranging from 120 to 180Ω / sq, and the cell efficiency is low.
[0040] The following is attached to the instruction manual Figure 1 To Attachment Figure 4 , the IBC battery cell diffusion method of the present invention is introduced.
[0041] In one embodiment, if Figure 1 As shown, the IBC cell diffusion method includes:
[0042] S100: arranging a plurality of battery groups at intervals, each battery group comprising two IBC battery sheets arranged opposite to each other at a first distance, and a distance between two adjacent battery groups is a second distance, and the second distance is greater than the first distance;
[0043] S200: Diffusion of the IBC cell sheet.
[0044] By making the distance between the back sides of the IBC battery cells different from the distance between the front sides, different square resistances of the same element on both sides can be achieved through one diffusion, thereby achieving one-time double-sided diffusion of the IBC battery without damaging the battery efficiency and without increasing the process steps, reducing the production process of the IBC battery and reducing production costs.
[0045] In one embodiment, in step S100, the first spacing is 2-3.5 mm, and the second spacing is 4-7 mm. Preferably, the first spacing is 2.5 mm, and the second spacing is 5 mm. In other embodiments, the specific spacing can be set according to actual needs, for example, the first spacing can also be 2.2 mm or 3 mm, and the second spacing can also be 4.5 mm or 6 mm.
[0046] In one embodiment, in step S200, the step of diffusing the IBC cell sheet includes:
[0047] In the diffusion stage, the IBC cell is placed in a diffusion furnace, and oxygen, pure nitrogen, and nitrogen carrying a phosphorus source or a boron source are introduced at a first set pressure. The temperature of the diffusion furnace is the first set temperature, and the diffusion is performed for 4-6 minutes.
[0048] In the advancement stage, the temperature of the diffusion furnace is raised to the second set temperature, and pure nitrogen and oxygen are introduced for diffusion for 20-30 minutes.
[0049] Preferably, the first set temperature is 750-850° C., the first set pressure is 200-300 mbar, and at the first set temperature, the flow rate of nitrogen gas carrying a phosphorus source or a boron source is 100-150 sccm, the flow rate of oxygen gas is 100-450 sccm, and the flow rate of pure nitrogen gas is 2000-4000 sccm;
[0050] The second set temperature is 850-910° C., the flow rate of the pure nitrogen gas introduced is 2000-4000 sccm, and the flow rate of the oxygen gas introduced is 8000-15000 sccm.
[0051] The square resistance of the front field passivation region of the finally formed IBC cell is 250-450Ω / sq, and the square resistance of the back field passivation region of the IBC cell after diffusion is 70-160Ω / sq.
[0052] Among them, pure nitrogen is usually called big nitrogen in the industry. Nitrogen carrying phosphorus source or boron source is usually called small nitrogen in the industry. Specifically, it means using small flow nitrogen to carry phosphorus source or boron source into the furnace tube. It can be considered that the phosphorus source or boron source is in a saturated state in the small flow nitrogen at this time. The larger the small nitrogen flow and the longer the ventilation time, the more phosphorus source or boron source is obtained in the furnace. Therefore, there is no specific ratio of phosphorus source or boron source in small nitrogen, which can be adjusted as needed.
[0053] In one embodiment, when the IBC cell is a FSF (Front Surface Field)-IBC cell, phosphorus diffusion is required, and preferably, the phosphorus source is phosphorus oxychloride POCl3. In other embodiments, other substances containing phosphorus element can also be selected as phosphorus source.
[0054] In one embodiment, the molar percentage of the phosphorus source is 2%-5%. Preferably, in this embodiment, the molar percentage of the phosphorus source in the nitrogen is 3.5%.
[0055] In other embodiments, when the IBC cell is a FFE (Front Floating Emitter)-IBC cell, boron diffusion is required, and preferably, the boron source is boron tribromide BBr3. In other embodiments, the boron source may also be boron trichloride BCl3.
[0056] Compared with the prior art, in the diffusion stage, the IBC cell diffusion method of this embodiment only needs to slightly increase the pressure to improve the utilization rate of the process gas. By comparison, it can be found that the use of phosphorus oxychloride POCl3 as a phosphorus source is reduced by 50%-70%, which greatly reduces the use of process gas and reduces costs. In the diffusion stage, due to the different spacing between the front and back sides of the IBC cell, the concentration difference of the BSG (boron-doped silicon glass) layer deposited on the front and back sides during deposition has been effectively controlled. Due to the large spacing on the back side, a larger concentration difference is formed in the deposition part (compared with the conventional double-sided same square resistance method). Therefore, in the subsequent high-temperature advancement stage, only a lower advancement temperature is required to achieve the advancement effect. Compared with the prior art, the temperature is about 20-40°C lower, and the conventional diffusion machine has a heating rate of 6-8°C / min and a cooling rate of 4-5°C / min, so the overall process can shorten the process time by 10 minutes.
[0057] In addition, as shown in the following Table 1, in the following Table 1, Uoc represents the open circuit voltage, Isc represents the short circuit current, FF represents the fill factor, and Eta represents the energy conversion efficiency. It is found through experiments that the energy conversion efficiency of the IBC battery prepared by the IBC battery cell diffusion method of the present invention is higher than that of the prior art.
[0058] Table 1
[0059]
[0060] In one embodiment, before placing the IBC cells into the diffusion furnace, multiple battery packs are placed on a quartz boat, and then the entire boat of IBC cells is transferred into the diffusion furnace for diffusion. Accordingly, the spacing between the teeth of the quartz boat needs to be designed accordingly to meet the requirements.
[0061] Specifically, Figure 2 and Figure 3 As shown, the quartz boat includes a boat body 10 and a plurality of adjacent boat tooth groups arranged on the boat body, each boat tooth group includes two adjacent boat teeth 20, and the distance between the two boat teeth 20 in each boat tooth group is a first spacing G, which is used to arrange two IBC battery cells arranged with their front sides relatively spaced apart, and the distance between two adjacent boat tooth groups is a second spacing T, which is greater than the first spacing G.
[0062] In one of the embodiments, before placing the IBC cell into the diffusion furnace, the steps include: cleaning and texturing the IBC cell. Specifically, the IBC cell passes through a texturing solution containing hydrofluoric acid HF and nitric acid HNO3, and the texturing solution textures the surface of the IBC cell to perform texturing; the texturized IBC cell is subsequently cleaned by passing through a water tank, a sodium hydroxide NaOH tank, a water tank, a hydrochloric acid HCl tank, and a water tank in sequence. Of course, in other embodiments, texturing and cleaning can also be performed by other commonly used methods in the art.
[0063] In one of the embodiments, a mask area and a diffusion area are prepared on the back side of the IBC cell, and the mask area is used to isolate diffusion.
[0064] Preferably, there are a plurality of mask regions and a plurality of diffusion regions, and the mask regions A and the diffusion regions B are arranged alternately and spaced one by one. Figure 4 As shown, the mask area and the diffusion area are both strip-shaped areas. A mask layer is prepared first, and the mask layer can be a single film layer composed of one of silicon dioxide, aluminum oxide and silicon nitride, or a composite film layer composed of multiple films. After the mask layer is prepared, the diffusion area is formed by grooving.
[0065] The front side of the IBC cell uses a full diffusion method, while the back side uses a mask area and a diffusion area to perform local diffusion in an alternating manner. Combined with the different spacing distances, the difference in square resistance between the front and back sides can be more accurately controlled.
[0066] The present invention also provides an IBC cell sheet, including a front side and a back side. The IBC cell sheet is manufactured by the IBC cell sheet diffusion method described in any of the above embodiments. The IBC cell sheet diffusion method has been introduced in the above embodiments and will not be described in detail here.
[0067] The present invention also provides a quartz boat. Specifically, Figure 2 and Figure 3 As shown, the quartz boat includes a boat body 10 and a plurality of adjacent boat tooth groups arranged on the boat body 10, each of the boat tooth groups includes two adjacent boat teeth 20, and the distance between the two boat teeth 20 in each of the boat tooth groups is a first spacing G, which is used to arrange two IBC battery sheets with their front faces arranged oppositely and spaced apart, and the distance between two adjacent boat tooth groups is a second spacing T, and the second spacing G is greater than the first spacing T.
[0068] The quartz boat can implement the IBC cell diffusion method described in any of the above embodiments, and of course, can also be used to process other types of cells.
[0069] Specifically, the first spacing is 2-3.5 mm, and the second spacing is 4-7 mm. Preferably, the first spacing is 2.5 mm, and the second spacing is 5 mm. In other embodiments, the first spacing and the second spacing can be set according to actual needs. For example, the first spacing can also be 2.2 mm or 3 mm, and the second spacing can also be 4.5 mm or 6 mm.
[0070] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.
Claims
1. An IBC cell diffusion method, characterized in that: include: Arrange multiple battery groups at intervals, each battery group includes two IBC battery sheets arranged opposite to each other at a first distance, and the distance between two adjacent battery groups is a second distance, and the second distance is greater than the first distance; Diffusion of IBC cells.
2. The IBC cell diffusion method according to claim 1, characterized in that: The first spacing is 2-3.5 mm, and the second spacing is 4-7 mm.
3. The IBC cell diffusion method according to claim 1, characterized in that: The diffusion of the IBC cell sheet includes: In the diffusion stage, the IBC cell is placed in a diffusion furnace, and oxygen, pure nitrogen, and nitrogen carrying a phosphorus source or a boron source are introduced at a first set pressure. The temperature of the diffusion furnace is the first set temperature, and the diffusion is performed for 4-6 minutes. In the advancement stage, the temperature of the diffusion furnace is raised to the second set temperature, and pure nitrogen and oxygen are introduced for 20-30 minutes.
4. The IBC cell diffusion method according to claim 3, characterized in that: The first set temperature is 750-850°C, the first set pressure is 200-300mbar, and at the first set temperature, the flow rate of nitrogen carrying a phosphorus source or a boron source is 100-150sccm, the flow rate of oxygen is 100-450sccm, and the flow rate of pure nitrogen is 2000-4000sccm.
5. The IBC cell diffusion method according to claim 3, characterized in that: The second set temperature is 850-910° C., the flow rate of the pure nitrogen gas introduced is 2000-4000 sccm, and the flow rate of the oxygen gas introduced is 8000-15000 sccm.
6. The IBC cell diffusion method according to claim 3, characterized in that: The phosphorus source is phosphorus oxychloride.
7. The IBC cell diffusion method according to claim 3, characterized in that: The molar percentage of the phosphorus source is 2%-5%.
8. The IBC cell diffusion method according to claim 1, characterized in that: Multiple battery packs were placed on a quartz boat for diffusion.
9. The IBC cell diffusion method according to claim 1, characterized in that: The back side of the IBC cell is provided with a mask area and a diffusion area, wherein the mask area is used for isolating diffusion.
10. The IBC cell diffusion method according to claim 9, characterized in that: There are a plurality of the mask regions and a plurality of the diffusion regions, and the mask regions and the diffusion regions are arranged alternately and spaced one by one.
11. An IBC battery cell, characterized in that: It comprises a front side and a back side, and is manufactured by the IBC cell sheet diffusion method according to any one of claims 1 to 10.
12. A quartz boat, characterized in that: A method for implementing the IBC battery cell diffusion method according to any one of claims 1 to 10, comprising a boat body and a plurality of adjacent boat tooth groups arranged on the boat body, each of the boat tooth groups comprising two adjacent boat teeth, a distance between two boat teeth in each of the boat tooth groups being a first spacing, and being used for arranging two IBC battery cells arranged with opposite front faces spaced apart, a distance between two adjacent boat tooth groups being a second spacing, and the second spacing being greater than the first spacing.
13. The quartz boat according to claim 12, characterized in that: The first spacing is 2-3.5 mm, and the second spacing is 4-7 mm.