A method and device for removing film from battery cells by immersion

Abstract

The present invention discloses a method and device for immersing a battery cell to remove the film. The method comprises the following steps: placing the battery cell in a fixed position on a carrier; immersing the carrier carrying the battery cell in a film removal solution; and removing the mask attached to the battery cell by using one of jetting, bubbling, and top overflow, or a combination of two or more of these methods. This film removal method can quickly and efficiently remove the mask from the battery cell. During the mask removal process, the battery cell is fixedly placed on the carrier and comes into contact with the film removal solution, effectively removing the mask from the battery cell and keeping the battery cell clean. During the film removal process, only the carrier needs to be transported to transport the battery cell, avoiding the risk of hidden cracks, fragments, or scratches on the battery cell during the film removal process, thereby improving the yield of the battery cell.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic cell production, and in particular to a method and device for immersion-type film removal of a cell. Background Art

[0002] Against the backdrop of carbon neutrality, the widespread and large-scale application of photovoltaic power generation technology will be further promoted. The current mainstream process for manufacturing metal grid lines on solar cells (photovoltaic silicon wafers) is to screen-print conductive silver paste onto the cells and then sinter it. However, this conductive silver paste is relatively expensive. To reduce process costs, the lower-cost copper plating process for producing metal grid lines has been industrialized on a large scale. The copper plating process requires first forming a mask on the surface of the cell, then opening the mask, and then depositing copper metal into the mask opening to form the metal grid lines. Finally, the mask is removed.

[0003] In existing technology, after the metal grid lines on the cell are prepared, the cell is usually transported using chain conveyor equipment. During the transport process, a film stripping solution is sprayed on the mask on the cell to remove the mask. However, due to the thin and fragile nature of cell cells, and the trend of becoming thinner and thinner, chain conveyor equipment carries the risk of cell cracking or even fragmentation, especially for cell cells with a thickness of less than 120μm. The risk of fragmentation is also greater. Furthermore, the rollers used during the transport process come into contact with the cell surface, which also creates the risk of scratching the cell, resulting in a reduction in cell yield.

[0004] On the other hand, existing technologies also include methods and equipment for removing the dielectric layer on the surface of solar cells. This dielectric layer is a functional layer on the surface of the solar cell, with a thickness of approximately 100nm. Generally, quality issues with the dielectric layer are caused by coating anomalies, so it is necessary to remove the dielectric layer and then re-coat it to generate a qualified dielectric layer. For example, Chinese patent CN211479986U discloses a film removal device, and Chinese patent CN112670166A discloses a rework and cleaning method for PERC cell PECVD-coated defective cells. These patents remove the defective dielectric layer on the solar cell.

[0005] The mask is an auxiliary layer that needs to be removed during the battery cell production process. The mask material generally cannot be completely dissolved, resulting in mask fragments during the mask dissolution process. Some mask fragments are suspended matter. It is very difficult to extract the carrier and battery cells from the mask fragments suspended around them in the mask removal liquid to prevent the mask fragments from adhering to the carrier and battery cells.

[0006] Therefore, it is necessary to find a new way to remove the film to solve one or more of the above problems. Summary of the Invention

[0007] The first object of the present invention is to provide a method for removing the film of a battery cell by immersion, so as to reduce the risk of damage to the battery cell during the film removal process and improve the yield of the battery cell.

[0008] To achieve the above object, the technical solution adopted by the present invention is a method for removing the film of a battery cell by immersion, comprising the following steps:

[0009] S1. Place the battery cell securely in the carrier;

[0010] S2, immersing the carrier carrying the battery cells in the film removal solution;

[0011] S3. Using one of jetting, bubbling and top overflow or a combination of two or more of these methods to remove the mask attached to the battery cell.

[0012] In some embodiments, in step S3, when the mask attached to the cell is removed by a jet, the mask removal liquid is sprayed toward multiple surfaces of the cell simultaneously, or the mask removal liquid is sprayed toward different surfaces of the cell in sequence.

[0013] In some embodiments, in step S3, when bubbling is used to remove the mask attached to the battery cell, gas is blown into the de-masking solution toward the battery cell in a single fixed direction to form unidirectional bubbling, or gas is blown into the de-masking solution toward the battery cell in multiple different directions simultaneously or sequentially to form multi-directional bubbling.

[0014] In some embodiments, in step S3, when the mask attached to the battery cell is removed by top overflow, stripping liquid is continuously added to the stripping tank so that the stripping liquid overflows at a position higher than the top of the carrier and the battery cell.

[0015] In some embodiments, in step S3, the mask attached to the battery cell is removed by combining a jet and a top overflow, or the mask attached to the battery cell is removed by combining bubbling and a top overflow, or the mask attached to the battery cell is removed by combining a jet, bubbling and a top overflow.

[0016] In some embodiments, in step S1, the battery cell extends in the up-down direction in the carrier, and the carrier is provided with a positioning groove for clamping and fixing a single battery cell, and the bottom edge portion and the two side edges extending in the up-down direction of the battery cell are respectively clamped in the positioning groove; in step S3, when the jet method is adopted, the jet is directed toward the bottom edge portion and the two side edges simultaneously or sequentially; when the bubbling method is adopted, the bubbling is directed toward the bottom edge portion and the two side edges simultaneously or sequentially.

[0017] In some embodiments, in step S3, the spraying or bubbling is performed in a direction perpendicular to the side edge portion, and / or the spraying or bubbling is performed in a direction perpendicular to the bottom edge portion.

[0018] In some embodiments, the battery cell extends vertically in the carrier, the top of the carrier has an opening, and the top edge of the battery cell is exposed in the opening or outside the opening.

[0019] In some embodiments, the carrier carries multiple battery cells at the same time, and all of the battery cells are spaced apart from each other in the carrier.

[0020] Preferably, the film removal method further comprises:

[0021] S4. The carrier is taken out from the stripping tank containing the stripping liquid, and during and / or after the removal, the carrier and / or the battery cell are sprayed with the stripping liquid for cleaning, thereby removing the mask fragments attached to the carrier and / or the battery cell.

[0022] In some embodiments, the carrier carrying the battery cells is taken out from a stripping tank containing a stripping solution, and during and / or after the removal, the carrier and / or the battery cells are sprayed with the stripping solution for cleaning.

[0023] Furthermore, in the process of removing the carrier carrying the battery cells from the defilming liquid, the carrier carrying the battery cells is first sunk to the bottom of the defilming tank, and then moved horizontally a certain distance from the bottom of the defilming tank, and then the carrier carrying the battery cells is lifted from the bottom of the defilming tank and taken out.

[0024] In some embodiments, the film removal tank has two film removal cavities, the upper parts of the two film removal cavities are separated from each other, and the bottom of the film removal tank has a transmission channel connecting the two film removal cavities and capable of allowing the carrier to translate and change positions.

[0025] In some embodiments, during the process of removing the carrier carrying the battery cells from the stripping solution, the carrier carrying the battery cells is driven to move in the stripping tank, and the moving direction of the carrier carrying the battery cells is different from the flow direction of the mask fragments in the stripping solution.

[0026] Preferably, the stripping solution is an alkaline solution with a concentration of 0.5 to 8 wt %. In some embodiments, the stripping solution is a sodium hydroxide solution or a potassium hydroxide solution, and the stripping solution contains a defoaming agent and / or a tin surface protective agent.

[0027] Preferably, the mask has a thickness of 2 μm to 20 μm and is made of an organic polymer material. In some embodiments, the organic polymer material is a thermosetting resin or a photosensitive resin, and the cell is covered with at least one of a transparent conductive oxide layer, a dielectric layer, and a metal seed layer.

[0028] The second object of the present invention is to provide a battery cell immersion type film removal device.

[0029] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is a battery cell immersion film removal device, which is used to implement the above-mentioned film removal method.

[0030] In some embodiments, the film removal device comprises:

[0031] A carrier for fixing and carrying battery cells, wherein the battery cells extend in the vertical direction on the carrier, wherein the carrier is provided with a positioning groove for clamping and fixing a single battery cell, wherein the bottom edge and two side edges extending in the vertical direction of the battery cell are respectively clamped in the positioning groove, and the top of the carrier has an opening, and the top edge of the battery cell is exposed in or outside the opening;

[0032] a film stripping tank having a film stripping cavity capable of accommodating the carrier;

[0033] The demolding device also includes at least one of a liquid spraying mechanism capable of spraying demolding liquid in a specific direction, a bubbling mechanism capable of generating gas along a specific direction to form bubbles in the demolding liquid in the demolding cavity, and an overflow mechanism capable of causing the demolding liquid in the demolding cavity to overflow from above the carrier to the outside of the demolding cavity.

[0034] Preferably, the spraying direction of the liquid spraying mechanism is perpendicular to the bottom edge and / or perpendicular to the side edge; the direction in which the gas is generated by the bubbling mechanism is perpendicular to the bottom edge and / or perpendicular to the side edge, and the overflow mechanism has at least an overflow port, and when the carrier carrying the battery cell is placed in the working position in the de-membrane chamber, the overflow port is higher than the highest point of the battery cell in the carrier in the vertical direction.

[0035] In some embodiments, there are a plurality of positioning grooves spaced apart along the same straight line direction, and all of the battery cells on the carrier extend along the vertical direction and are spaced apart from each other.

[0036] In some embodiments, the liquid spraying mechanism / the bubbling mechanism is provided in one or more groups, and the liquid spraying mechanism / the bubbling mechanism is provided close to the bottom wall of the film removal tank and / or close to the side wall of the film removal tank.

[0037] In some embodiments, the film removal device at least has the overflow mechanism, and the film removal device further includes one or both of the liquid spraying mechanism and the bubbling mechanism.

[0038] In some embodiments, the overflow mechanism includes an overflow valve having the overflow port and an overflow pipe interconnected with the overflow valve, the overflow pipe is located outside the film removal cavity, and the overflow port is interconnected with the film removal cavity.

[0039] In some embodiments, the film removal tank has two film removal cavities, the upper parts of the two film removal cavities are separated from each other, and the bottom of the film removal tank has a transmission channel connecting the two film removal cavities and capable of allowing the carrier to translate and change positions.

[0040] In some embodiments, the film removal device further includes a transmission device for transmitting the carrier, and the transmission device is disposed at the bottom of the film removal tank and passes through the transmission channel.

[0041] Preferably, the film removal device further includes a film liquid circulation mechanism, and the film liquid circulation mechanism includes:

[0042] a liquid outlet pipe, arranged outside the film removal tank and connected to the film removal cavity;

[0043] a membrane-liquid separator, arranged on the liquid outlet path of the liquid outlet pipe, the membrane-liquid separator having a filtering component for filtering out the mask and transmitting the filtered mask along a specific transmission path;

[0044] a film collector, provided at the end of the transmission path and used for collecting the mask filtered out by the filtering component;

[0045] A filter box having a filter chamber disposed below the membrane liquid separator;

[0046] A circulation pipe is connected between the filter box and the membrane removal tank.

[0047] In some embodiments, a filter screen is further provided on the top of the filter cavity.

[0048] In some embodiments, the bottom cross-section of the film removal tank decreases from top to bottom, and the liquid outlet pipe is connected to the bottom end of the film removal tank.

[0049] In some embodiments, the filter component is arranged to extend gradually downward from the liquid outlet pipe toward the film collector.

[0050] Due to the application of the above-mentioned technical solution, the present invention has the following advantages compared with the prior art: by implementing the battery cell immersion de-filming method of the embodiment of the present invention, the mask on the battery cell can be removed quickly and efficiently. During the mask removal process, the battery cell is fixedly placed on the carrier and contacts and reacts with the de-filming liquid, which effectively removes the mask on the battery cell and keeps the battery cell clean. This method uses a static immersion method for de-filming, which abandons the method of synchronously spraying the de-filming liquid during chain conveying in the prior art, avoids the risks of hidden cracks, fragments or scratches during chain transportation, and improves the yield of the battery cell. The battery cell immersion de-filming method in the embodiment of the present invention has a simple process and is convenient for large-scale industrial application. The battery cell immersion de-filming device in the embodiment of the present invention is also simple in structure and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Attachment Figure 1 Schematic diagram of the process of the film removal method of the present invention;

[0052] Attachment Figure 2 Schematic diagram of the principle of the first embodiment of the film removal method of the present invention;

[0053] Attachment Figure 3 It is a schematic diagram of the principle of a second embodiment of the film removal method of the present invention;

[0054] Attachment Figure 4 Schematic diagram of the principle of the third embodiment of the film removal method of the present invention;

[0055] Attachment Figure 5 Schematic diagram of the principle of the fourth embodiment of the film removal method of the present invention;

[0056] Attachment Figure 6 A schematic diagram of the principle of removing the carrier and the battery cell from the film stripping solution in one embodiment of the present invention;

[0057] Attachment Figure 7 is a schematic longitudinal cross-sectional view of a carrier carrying a battery cell in one embodiment of the present invention;

[0058] Attachment Figure 8 is a schematic diagram of the overall structure of a carrier used in another specific embodiment of the present invention;

[0059] Attachment Figure 9 For attachment Figure 8 A schematic diagram of the main structure of the vehicle;

[0060] Attachment Figure 10 For the attachment Figure 9 AA-axis cross-sectional structural diagram;

[0061] Attachment Figure 11 A schematic diagram of the positional relationship between the battery cell and the carrier when the battery cell is placed on the carrier;

[0062] Attachment Figure 12 A schematic structural diagram of a film removal device according to a specific embodiment of the present invention;

[0063] Attachment Figure 13 A schematic structural diagram of a film removal device according to another embodiment of the present invention;

[0064] Among them: 1. Demembrane tank; 1a, 1b, demembrane cavity; 2. Battery cell; 3. Carrier; 31. Fixing plate; 32. Connecting column; 33. Partition; 34. Card slot; 4. Transmission device; 5. Bubble mechanism; 6. Overflow mechanism; 6a. Overflow valve; 6b. Overflow pipe; 7. Liquid outlet pipe; 8. Filter box; 9. Membrane-liquid separator; 10. Membrane collector; 11. Filter screen; 12. Reflux outlet pipe; 13. Reflux inlet pipe. DETAILED DESCRIPTION

[0065] Against the backdrop of carbon neutrality, the widespread and large-scale application of photovoltaic power generation technology will be further promoted. The current mainstream process for manufacturing metal grid lines on solar cells (photovoltaic silicon wafers) is to screen-print conductive silver paste onto the cells and then sinter it. However, this conductive silver paste is relatively expensive. To reduce process costs, the lower-cost copper plating process for producing metal grid lines has been industrialized on a large scale. The copper plating process requires first forming a mask on the surface of the cell, then opening the mask, and then depositing copper metal into the mask opening to form the metal grid lines. Finally, the mask is removed.

[0066] In existing technology, after the metal grid lines on the cell are prepared, the cell is usually transported using chain conveyor equipment. During the transport process, a film stripping solution is sprayed on the mask on the cell to remove the mask. However, due to the thin and fragile nature of cell cells, and the trend of becoming thinner and thinner, chain conveyor equipment carries the risk of cell cracking or even fragmentation, especially for cell cells with a thickness of less than 120μm. The risk of fragmentation is also greater. Furthermore, the rollers used during the transport process come into contact with the cell surface, which also creates the risk of scratching the cell, resulting in a reduction in cell yield.

[0067] On the other hand, existing technologies also include methods and equipment for removing the dielectric layer on the surface of solar cells. This dielectric layer is a functional layer on the surface of the solar cell, with a thickness of approximately 100nm. Generally, quality issues with the dielectric layer are caused by coating anomalies, so it is necessary to remove the dielectric layer and then re-coat it to generate a qualified dielectric layer. For example, Chinese patent CN211479986U discloses a film removal device, and Chinese patent CN112670166A discloses a rework and cleaning method for PERC cell PECVD-coated defective cells. These patents remove the defective dielectric layer on the solar cell.

[0068] The mask is an auxiliary layer that needs to be removed during the battery cell production process. The mask material generally cannot be completely dissolved, resulting in mask fragments during the mask dissolution process. Some mask fragments are suspended matter. It is very difficult to extract the carrier and battery cells from the mask fragments suspended around them in the mask removal liquid to prevent the mask fragments from adhering to the carrier and battery cells.

[0069] In response to the above-mentioned problems existing in the prior art, the present invention application proposes a method for removing the film from the battery cell by immersion. The main purpose is to remove the mask on the battery cell in a safer way, reduce the risk of hidden cracks, fragments or scratches during the battery cell removal process, and thereby improve the yield of the battery cell.

[0070] like Figure 1 As shown, the cell immersion film removal method includes the following steps:

[0071] S1, placing the battery cell 2 fixedly in the carrier 3;

[0072] S2, immersing the carrier 3 carrying the battery cell 2 in a film removal solution;

[0073] S3. Remove the mask attached to the battery cell 2 by using one of the following methods: jetting, bubbling, and top overflow, or a combination of two or more of these methods.

[0074] In the embodiment of the present application, the mask on the cell 2 has a thickness of 2μm to 20μm. The mask is made of an organic polymer material, such as a thermosetting resin or a photosensitive resin. The cell coated with the organic polymer material is covered with at least one of a transparent conductive oxide layer, a dielectric layer, and a metal seed layer. The dielectric layer may be a silicon nitride layer, a silicon oxynitride layer, an aluminum oxide layer, or a magnesium fluoride layer. The metal seed layer may be a single layer, a laminate, or an alloy layer containing copper, titanium, tungsten, aluminum, nickel, or tin. The mask covers the outermost surface of the cell 2. After the grid lines are formed on the cell using a copper plating process, the mask on the surface of the cell 2 is removed using the above-mentioned film removal method.

[0075] The aforementioned methods of jetting, bubbling, or top overflow can all accelerate the flow of the stripping solution around the cell 2, allowing the mask attached to the cell 2 to fully contact the stripping solution and react, thereby making it easier to detach from the cell 2. During the flow of the stripping solution, the mask fragments detached from the cell 2 will flow away from the cell 2 and avoid adhering to the surface of the cell 2. The stripping solution specifically uses an alkaline solution with a concentration of 0.5 to 8 wt%, preferably a sodium hydroxide solution or a potassium hydroxide solution. In some embodiments, the stripping solution also contains a defoaming agent. In other embodiments, when tin is present on the surface of the electroplated layer on the cell 2, a tin surface protective agent is added to the stripping solution.

[0076] It should be noted that the battery cells 2 in the embodiments of the present invention include two states: a coated battery cell and a stripped battery cell. A coated battery cell is a battery cell 2 whose mask has not yet been removed, and a stripped battery cell is a battery cell 2 whose mask has been removed. The battery cells 2 mentioned in the embodiments of the present invention should be understood as coated battery cells and / or stripped battery cells according to the context. For example, the battery cell 2 in steps S1-S3 is a coated battery cell, while the battery cell 2 in step S4 below is a stripped battery cell.

[0077] It should be noted that the carrier 3 in the embodiments of the present invention includes an unloaded state and a loaded state. The unloaded state refers to a state in which no battery cell 2 has been loaded, and the loaded state refers to a state in which a battery cell 2 has been loaded. The carrier 3 in the embodiments of the present invention should be understood as being in an unloaded state or a loaded state depending on the context. If the carrier 3 is in a loaded state, operations performed on the carrier 3 may extend to the battery cell 2 loaded by the carrier 3.

[0078] When the mask attached to the cell 2 is removed by jetting, Figure 2 As shown, one or more spray mechanisms can be used, each capable of spraying the stripping liquid in a specific direction. Specifically, the stripping liquid can be sprayed toward a single surface of the cell 2, or alternatively, toward different surfaces of the cell 2 in sequence. Alternatively, multiple spray mechanisms can be used to simultaneously spray the stripping liquid toward different surfaces of the cell 2. The sprayed stripping liquid can accelerate the flow of the stripping liquid around the cell 2, accelerating the detachment of the mask from the cell 2. The detached mask fragments are then carried away from the cell 2 by the flow of the stripping liquid, achieving separation from the cell 2.

[0079] When the mask attached to the cell 2 is removed by bubbling, Figure 3 As shown, one or more bubbling mechanisms can be used, each of which can generate gas in a specific direction to form bubbles in the de-masking solution. Specifically, gas can be blown into the de-masking solution in a single fixed direction toward the battery cell 2 to form unidirectional bubbles, or gas can be blown into the de-masking solution in multiple different directions simultaneously or sequentially toward the battery cell 2 to form multi-directional bubbles. After bubbles are formed in the de-masking solution, the de-masking solution at the corresponding position fluctuates and acts on the battery cell 2, accelerating the flow of the de-masking solution around the battery cell 2, thereby accelerating the detachment of the mask from the battery cell 2. The detached mask fragments move away from the battery cell 2 along with the flow of the de-masking solution, thereby achieving separation from the battery cell 2.

[0080] When the mask attached to the cell 2 is removed by top overflow, as shown in FIG. Figure 4As shown, stripping liquid is continuously added to the stripping tank 1 until it overflows above the top of the carrier 3 and the cell 2. This increase in stripping liquid accelerates its flow within the stripping tank 1, accelerating the detachment of the mask from the cell 2. Simultaneously, due to buoyancy, the mask fragments detached from the cell 2 float upward and are discharged from the stripping tank 1 along with the overflowing stripping liquid.

[0081] When removing the mask, one of the three methods, namely, jet flow, bubbling and top overflow, can be selected, or a combination of any two of them can be selected, or a combination of the three methods can be selected. In some preferred embodiments, a combination of jet flow and top overflow is used to remove the mask attached to the battery cell 2, or as Figure 5 As shown, the mask attached to the battery cell 2 is removed by combining bubbling with top overflow, or by combining jetting, bubbling with top overflow. The mask removal efficiency is higher, and the mask fragments that fall off the battery cell 2 are not easy to adhere to the battery cell 2 again.

[0082] See also Figures 2 to 5 ,as well as Figure 7 As shown, the battery cell 2 extends vertically on the carrier 3. The carrier 3 is provided with a positioning groove (not shown) for clamping and fixing a single battery cell 2. The bottom edge of the battery cell 2 and the two side edges extending in the vertical direction are respectively clamped in the above-mentioned positioning grooves. The battery cell 2 extends vertically or slightly inclined on the carrier 3. The top of the carrier 3 has an opening, and the top edge of the battery cell 2 is exposed in the opening or outside the opening. Here, see Figure 6 As shown, the top edge of the battery cell 2 is exposed above the opening of the carrier 3. The carrier 3 has a plurality of positioning grooves spaced apart along the same straight line direction, so that the carrier 3 can simultaneously fix and carry multiple battery cells 2. Here, all the battery cells 2 are spaced apart from each other on the carrier 3. When the carrier 3 carrying the battery cells 2 is completely immersed in the de-filming liquid, except for the area in contact with the positioning grooves, the other parts of the outer surface of the battery cell 2 can fully contact and react with the de-filming liquid without causing too much disturbance or turbulence. At the same time, each battery cell 2 is physically isolated on the carrier 3 by the positioning grooves. When immersed in the de-filming liquid, when encountering fluid force causing swinging, there will be no problem of two battery cells 2 adhering to each other due to the surface tension of the liquid and being difficult to separate.

[0083] In some embodiments, hollow holes are further provided on the carrier 3. These hollow holes are arranged on the outside of the positioning groove and are interconnected with the positioning groove, so that the defilming liquid can fully enter the positioning groove and fully contact the side and / or bottom edges of the battery cell 2 stuck in the positioning groove.

[0084] See also Figures 8 to 10 Another carrier 3 structure is shown. This carrier 3 includes two fixed plates 31 disposed at left and right ends, and a plurality of connecting columns 32 fixedly connected between the two fixed plates 32. Here, there are four connecting columns 32, and the axis lines of these four connecting columns 32 are parallel to each other. Two connecting columns 32 are disposed at intervals along the front-to-back direction on the upper portion of the fixed plates 32, and the other two connecting columns 32 are disposed at intervals along the front-to-back direction on the lower portion of the fixed plates 32. The spacing between the two upper connecting columns 32 is slightly larger than the spacing between the two lower connecting columns 32. Each connecting column 32 is provided with a plurality of partitions 33 spaced along the length, and slots 34 are formed between adjacent partitions 33. Four groups of slots 34 at the same position along the left-to-right direction on the four connecting columns 32 cooperate to form positioning grooves for locking and positioning individual battery cells 2. Here, the partition 33 is fixedly mounted on the outer periphery of the connecting column 32 in a disc shape. When the battery cell 2 is opened in the above-mentioned positioning groove, the contact area between the battery cell 2 and the positioning groove is small, so that the mask liquid and the side and / or bottom edges of the battery cell 2 are further fully contacted. At the same time, the probability of mask fragments getting stuck in the positioning groove and the gap between the positioning groove and the battery cell 2 is also reduced.

[0085] When the mask on the cell 2 is removed by jetting, the jetting can be performed simultaneously or sequentially in a direction perpendicular to the bottom edge and two side edges of the cell 2 stuck in the positioning groove of the carrier 3, such as Figure 2 As shown, that is, the jetting direction of the jet mechanism is perpendicular to the bottom edge of the battery cell 2 or perpendicular to the two side edges of the battery cell 2. When the mask on the battery cell 2 is removed by bubbling, bubbling can be performed simultaneously or sequentially in the direction perpendicular to the bottom edge and the two side edges of the battery cell 2 stuck in the positioning groove of the carrier 3, as shown in FIG. Figure 3 As shown, that is, the direction in which the gas generated by the bubbling mechanism is directed perpendicularly toward the bottom edge of the battery cell 2 or perpendicularly toward the two side edges of the battery cell 2. This allows the bottom edge and side edges of the battery cell 2 stuck in the positioning groove to more fully come into contact with the film removal liquid, accelerating the detachment of the mask from the battery cell 2. At the same time, it can also better remove mask fragments in the positioning groove, on the side edges and bottom edges of the battery cell 2 stuck in the positioning groove, and in the gaps between the positioning groove and the side edges and bottom edges of the battery cell 2, thereby fully removing the mask and preventing mask fragments from adhering to the battery cell 2.

[0086] When the top overflow method is used to remove the mask on the battery cell 2, when the carrier 3 carrying the battery cell 2 is placed in the working position of the film removal tank, the overflow port of the overflow mechanism is higher than the highest point of the battery cell 2 in the carrier 3 in the vertical direction, such as Figure 4As shown, under the action of buoyancy, the mask fragments in the positioning grooves of the carrier 3, on the side and bottom edges of the battery cell 2 stuck in the positioning grooves, and in the gaps between the positioning grooves and the side and bottom edges of the battery cell 2 can float upward unimpeded, accelerating the separation of the mask fragments from the carrier 3 and the battery cell 2. When jetting or bubbling is combined with top overflow, the mask removal efficiency is higher, and the mask fragments are less likely to adhere to the carrier 3 and the battery cell 2, resulting in a better removal effect.

[0087] The prior art does not use the method of soaking the cell in the masking liquid to remove the mask. The main reasons include: after the cell 2 is soaked, the mask fragments float above the cell and are likely to adhere to the cell 2 again; when the cell 2 is removed from the masking liquid, the mask fragments will adhere to the cell again; when the cell 2 is carried by the carrier 3, the mask fragments are likely to get stuck in the gap near the contact point between the carrier 3 and the cell 2, making it difficult to remove. Therefore, in some embodiments, such as Figure 1 As shown, the de-filming method also includes step S4, taking out the carrier 3 carrying the battery cell 2 from the de-filming liquid, and spraying the de-filming liquid on the outer surface of the carrier 3 and / or the battery cell 2 for cleaning during and / or after the taking out, so that the mask fragments that may be adhered to the carrier 3 and / or the battery cell 2 again during the process of the carrier 3 carrying the battery cell 2 breaking through the liquid surface of the de-filming liquid are cleaned, so that the battery cell 2 after the de-filming is kept clean. The preferred method is that during and after the carrier 3 carrying the battery cell 2 is taken out from the de-filming liquid, the carrier 3 and the battery cell 2 are sprayed with the de-filming liquid for cleaning, and the mask fragments are removed again by cleaning, so that the battery cell 2 and the carrier 3 after the de-filming are kept clean.

[0088] Furthermore, in step S4, in the process of taking the carrier 3 carrying the battery cell 2 out of the de-filming liquid, the carrier 3 carrying the battery cell 2 can be driven to move in the de-filming tank, and the moving direction of the carrier 3 carrying the battery cell 2 is different from the flow direction of the mask fragments in the de-filming liquid, so as to prevent the mask fragments from sticking back to the carrier 3 and / or the battery cell 2 when the carrier 3 carrying the battery cell 2 leaves the de-filming tank 1. In a specific embodiment, a liquid inlet is provided on the de-filming tank 1 upstream of the moving direction of the carrier 3, and a liquid outlet or overflow is provided on the de-filming tank 1 downstream of the moving direction of the carrier 3, so that the moving direction of the carrier 3 is different from the flow direction of the de-filming liquid, and the mask fragments flow with the de-filming liquid, which also makes the moving direction of the carrier 3 different from the flow direction of the mask fragments. In this embodiment, see Figure 6As shown, in the process of removing the carrier 3 carrying the battery cells 2 from the stripping solution, the carrier 3 carrying the battery cells 2 is first sunk to the bottom of the stripping tank 1, and after being translated a certain distance from the bottom of the stripping tank 1, the carrier 3 carrying the battery cells 2 is lifted from the bottom of the stripping tank 1 and removed. This can minimize the possibility of the carrier 3 and / or the battery cells 2 being contaminated with mask fragments again during the process of breaking the liquid surface of the stripping solution, so that the battery cells 2 and / or the carrier 3 after the stripping remain clean. The carrier 3 carrying the battery cells 2 will be subject to the resistance and buoyancy of the stripping solution during the sinking process, the translation process at the bottom of the stripping tank 1, and the lifting process from the bottom of the stripping tank 1. Under the action of the resistance and buoyancy of the stripping solution, the mask fragments on the carrier 3 and / or the battery cells 2 can be better removed.

[0089] In the specific configuration, the film stripping tank 1 has two film stripping chambers 1a and 1b. The upper parts of the film stripping chamber 1a and the film stripping chamber 1b are separated from each other. The bottom of the film stripping tank 1 also has a transmission channel that connects the film stripping chamber 1a and the film stripping chamber 1b and can allow the carrier 3 carrying the battery cell 2 to be translated and changed in position. The transmission channel is also provided with a transmission device 4 for transferring the carrier 3 carrying the battery cell 2 between the film stripping chamber 1a and the film stripping chamber 1b to change its position. In this way, when film stripping, the carrier 3 carrying the battery cell 2 is immersed in the film stripping chamber 1a. After the film stripping process is completed, the carrier 3 carrying the battery cell 2 is sunk to the bottom and is translated from the bottom of the film stripping tank 1a to the film stripping chamber 1b by the transmission device 4. Then, the carrier 3 carrying the battery cell 2 is lifted up and breaks out of the liquid surface of the film stripping chamber 1b. In the above process, when the carrier 3 carrying the battery cell 2 sinks in the de-masking chamber 1a, the de-masking liquid has an upward buoyancy on the mask fragments, and the mask fragments can fully break away from the carrier 3 and the battery cell 2 and float upward. Subsequently, when the carrier 3 and the battery cell 2 float upward in the de-masking chamber 1b, they are exposed to relatively clean de-masking liquid, which minimizes the possibility of the mask fragments adhering to the carrier 3 and the battery cell 2 again.

[0090] Preferably, the conveyor 4 can be one or a combination of a chain conveyor, a roller conveyor, and a belt conveyor. The conveyor 4 is located at the bottom of the film removal tank 1. When the carrier 3 sinks onto the conveyor 4 for conveying, the buoyancy reduces the vibration between the conveyor 4 and the carrier 3, thereby reducing the risk of cracks, fragments, or scratches on the conveyor 4 during the conveying process.

[0091] In other embodiments, in order to increase the reaction speed between the stripping solution and the mask, the temperature of the stripping solution in the stripping tank 1 can be controlled. Specifically, the stripping solution in the stripping tank 1 is circulated and heated so that the temperature of the stripping solution in the stripping tank 1 is maintained between 30°C and 60°C, preferably between 45°C and 55°C. After the carrier 3 is taken out of the stripping solution, since the carrier 3 and the battery cell 2 it carries are at a relatively high temperature, the stripping solution attached to the surface of the carrier 3 and the battery cell 2 it carries is easily evaporated and dried, causing impurities or unremoved mask fragments to be firmly attached to the surface of the carrier 3 and the battery cell 2 it carries, making it difficult to clean and remove. Therefore, in step S4, during and / or after the carrier 3 is removed from the stripping solution, the outer surface of the carrier 3 and the battery cell 2 carried thereon is immediately sprayed with cooled stripping solution for cleaning, thereby reducing the temperature of the carrier 3 and the battery cell 2 carried thereon, thereby reducing the volatilization rate of the stripping solution attached to the surface of the carrier 3 and the battery cell 2 carried thereon, and preventing impurities or unremoved mask fragments from firmly adhering to the surface of the battery cell 2, thereby facilitating subsequent cleaning processes. The temperature of the cooled stripping solution is lower than the temperature of the stripping solution and not lower than the freezing point of the stripping solution. The temperature of the cooled stripping solution can be 5°C-40°C, preferably 15°C-30°C. The temperature of the cooled stripping solution can also be room temperature, which is lower than 30°C, so that a cooled stripping solution can be easily obtained.

[0092] See also Figure 12 The figure shows a schematic structural diagram of a film stripping device according to a specific embodiment of the present invention. The film stripping device of this embodiment adopts a bubbling and top overflow method to achieve film stripping of the battery cell 2. Specifically, a bubbling mechanism 5 is provided with a group, specifically a bubbling tube, which is located near the bottom of the film stripping tank 1. The direction of the gas generated by the bubbling mechanism 5 is perpendicular to the bottom edge of the battery cell 2. The film stripping tank 1 is provided with an overflow mechanism 6. The overflow mechanism 6 includes an overflow valve 61 with an overflow port and an overflow tube 62 interconnected with the overflow valve 61. The overflow tube 62 is located outside the film stripping tank 1. The overflow port of the overflow valve 81 is interconnected with the film stripping chambers 1a and 1b. When the carrier 3 carrying the battery cell 2 is placed in the film stripping chambers 1a and 1b, the overflow port is vertically higher than the carrier 3 and the battery cell 2 on the carrier 3.

[0093] In other embodiments, when it is necessary to generate bubbles perpendicular to the side of the battery cell 2, a bubbling mechanism 5 can be set at a position close to the side wall of the film removal tank 1; when it is necessary to use a jet method to remove the film, a jet mechanism can be set at a position close to the side wall and / or bottom tank wall of the film removal tank 1.

[0094] The film removal device also includes a film liquid circulation mechanism, which is used to filter the film removal liquid in the film removal tank 1 and then inject it back into the film removal tank 1 for recycling. The film liquid circulation mechanism includes:

[0095] A liquid outlet pipe 7 is provided outside the film stripping tank 1 and communicates with the film stripping chambers 1a and 1b. The liquid outlet pipe 7 is provided at the bottom of the film stripping tank 1 or near the bottom to fully discharge the film stripping liquid in the film stripping tank 1. Here, the liquid outlet pipe 7 is provided on the side of the film stripping tank 1.

[0096] The membrane liquid separator 9 is provided on the liquid outlet path of the liquid outlet pipe 7 and the liquid outlet path of the overflow pipe 62. The membrane liquid separator 9 has a filtering component capable of filtering out the mask and transmitting the filtered mask along a specific transmission path. Specifically, the filtering component is a conveyor belt made of a membrane residue separation net, and the conveyor belt is rotatably provided on a synchronous pulley.

[0097] The film collector 10 is provided at the end of the transmission path of the membrane liquid separator 9, and is used to collect the mask filtered by the above-mentioned filter component;

[0098] Filter box 8 has a filter chamber located below membrane-liquid separator 9. Here, filter box 8 is entirely located below membrane-liquid separator 9. After the membrane-stripping liquid is filtered by the filter components, the mask fragments remain on the conveyor belt and are transported along the conveyor belt to the membrane collector 10. The filtered membrane-stripping liquid is then collected by filter box 8 below. A filter screen 11 is also installed on the top of filter box 8 to further filter the membrane-stripping liquid entering the filter chamber of filter box 8.

[0099] A circulation pipe (not shown) is connected between the filter box 8 and the membrane removal tank 1. A reflux outlet pipe 12 is provided on the outer side of the lower end of the filter box 8, and a reflux inlet pipe 13 is provided on the outer side of the upper end of the membrane removal tank 1. The circulation pipe is connected between the reflux outlet pipe 12 and the reflux inlet pipe 13 to replenish the membrane removal liquid after filtration in the filter box 8 to the membrane removal tank 1 for recycling.

[0100] See also Figure 13 The structure diagram of the film removal device of another embodiment of the present invention is shown. Figure 12Compared to the film removal device of the illustrated embodiment, the main differences are: First, in this embodiment, the bottom cross-section of the film removal tank 1 decreases from top to bottom, specifically configured as a cone with a larger top and a smaller bottom. The liquid outlet pipe 7 is connected to the bottom of the film removal tank 1. This ensures that the film removal liquid in the film removal tank 1 is fully discharged, preventing impurities deposited at the bottom of the film removal tank 1 from remaining in the film removal tank 1 and affecting the film removal effect. Second, in this embodiment, the filter component of the membrane liquid separator 9 and the filter screen 11 at the top of the filter box 8 are both inclined, extending gradually downward from the liquid outlet pipe 7 toward the film collector 10, which is more conducive to the transmission and collection of mask fragments. Third, the membrane liquid separator 9 is located inside the filter box 8. The filter box 8 is divided into an upper box and a lower box. The inner cavity of the lower box constitutes the filter chamber of the filter box 8. The lower box collects the filtered film removal liquid. The upper box prevents the film removal liquid from falling onto the membrane liquid separator 9 and splashing out of the filter box 8, while also providing a soundproofing effect.

[0101] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A cell immersion film removal method, characterized in that: The steps include: S1. Place the battery cell securely in the carrier; S2. Immerse the carrier carrying the battery cells in a stripping solution in a stripping tank, wherein the stripping tank has two stripping chambers, the upper portions of the two stripping chambers are separated from each other, and the bottom of the stripping tank has a transmission channel connecting the two stripping chambers and capable of allowing the carrier to translate and change positions; S3, using one of jetting, bubbling and top overflow, or a combination of two or more of these methods, to remove the mask attached to the battery cell; S4. Take the carrier carrying the battery cells out of the film stripping tank. In the process of taking the carrier carrying the battery cells out of the film stripping liquid, first sink the carrier carrying the battery cells to the bottom of the film stripping tank, drive the carrier carrying the battery cells to move in the film stripping tank, and the moving direction of the carrier carrying the battery cells is different from the flow direction of the mask fragments in the film stripping liquid. After moving horizontally for a certain distance from the bottom of the film stripping tank, the carrier carrying the battery cells is lifted from the bottom of the film stripping tank and taken out.

2. The cell immersion film removal method according to claim 1, characterized in that: In step S3, when the mask attached to the cell is removed by jetting, the mask removal liquid is sprayed toward multiple surfaces of the cell simultaneously, or the mask removal liquid is sprayed toward different surfaces of the cell in sequence.

3. The cell immersion film removal method according to claim 1, characterized in that: In step S3, when the mask attached to the battery cell is removed by bubbling, gas is blown into the de-masking solution toward the battery cell in a single fixed direction to form unidirectional bubbling, or gas is blown into the de-masking solution toward the battery cell in multiple different directions simultaneously or sequentially to form multi-directional bubbling.

4. The cell immersion film removal method according to claim 1, characterized in that: In step S3, when the mask attached to the cell is removed by top overflow, stripping liquid is continuously added to the stripping tank so that the stripping liquid overflows at a position higher than the top of the carrier and the cell.

5. The cell immersion film removal method according to claim 1, characterized in that: In step S1, the battery cell extends in the vertical direction in the carrier, and the carrier is provided with a positioning groove for clamping and fixing a single battery cell, and the bottom edge and two side edges extending in the vertical direction of the battery cell are respectively clamped in the positioning groove; In the step S3, when the jetting method is adopted, the jetting is performed toward the bottom edge and the two side edges simultaneously or sequentially; when the bubbling method is adopted, the bubbling is performed toward the bottom edge and the two side edges simultaneously or sequentially.

6. The cell immersion film removal method according to claim 5, characterized in that: In the step S3, the jetting or bubbling is performed in a direction perpendicular to the side edge, and / or the jetting or bubbling is performed in a direction perpendicular to the bottom edge.

7. The cell immersion film removal method according to claim 5, characterized in that: The battery cell extends in a vertical direction in the carrier. The top of the carrier has an opening, and the top edge of the battery cell is exposed in the opening or outside the opening.

8. The cell immersion film removal method according to claim 5, characterized in that: The carrier carries a plurality of battery cells at the same time, and all the battery cells are arranged at intervals from each other in the carrier.

9. The cell immersion film removal method according to claim 1, characterized in that: During and / or after the carrier carrying the battery cells is taken out of the stripping tank containing the stripping liquid, the carrier and / or the battery cells are sprayed with the stripping liquid for cleaning.

10. The cell immersion film removal method according to any one of claims 1 to 9, characterized in that: The thickness of the mask is 2 μm to 20 μm, and the material of the mask is an organic polymer material.

11. The cell immersion film removal method according to claim 10, characterized in that: The organic polymer material is a thermosetting resin or a photosensitive resin, and the cell is covered with at least one of a transparent conductive oxide layer, a dielectric layer and a metal seed layer.

12. A cell immersion film removal device, characterized in that: Used to implement the film removal method according to any one of claims 1 to 11.

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