A method and apparatus for horizontal plating of battery cells

Abstract

The application discloses a method and device for horizontal electroplating of a battery piece, wherein a flexible conductive piece is fixedly attached to an opening of a mask on a plated surface of the battery piece, so that an electrical connection is formed between the flexible conductive piece and the battery piece, and metal material can be electroplated in the opening of the mask on one side or two sides of the battery piece, thereby avoiding the problems of cracked or broken pieces caused by clamping of the battery piece by a hard conductive point in the prior art.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell and semiconductor manufacturing, and more specifically to a method for horizontal electroplating of cells, and an apparatus for implementing the method, for simultaneously depositing metal electrodes on one or both sides of the cell. Background Technology

[0002] To further reduce the cost and improve the power generation efficiency of solar cells, the use of electroplated copper to replace screen-printed silver paste in the fabrication of metal grid lines for solar cells is receiving increasing attention and research. With the trend towards thinner solar cells, the method of using hard conductive points to clamp the cells, borrowed from electroplating equipment in the PCB or semiconductor industries, faces increasing challenges. Imprints or microcracks left at the clamping points negatively impact the appearance and power generation efficiency of photovoltaic cells to some extent. There are also precedents for developing horizontal electroplating equipment by borrowing and modifying the transmission methods of horizontal texturing or etching equipment for solar cells.

[0003] One of the application technologies of horizontal electroplating in the photovoltaic field is to use a conductive brush to contact one side of the solar cell while keeping that side dry, and then use photo-induced electroplating on the other side of the solar cell, such as CN101796222B. In this method, a roller is used to transport the solar cell, and a conductive brush is used to provide electrical connection on the other side of the solar cell to be plated. This technology requires that a metal layer be deposited on the contact surface of the conductive brush in advance. Therefore, it is not suitable for solar cell structures that require metal grid lines to be electroplated on both sides, such as heterojunction cells or topcon cells. It is also not suitable for solar cells where the metal grid lines exist only on one side of the solar cell, such as back contact solar cells (IBC or TBC structures). In addition, the conductive brush is prone to scratching the surface of the solar cell.

[0004] Horizontal double-sided electroplating technology typically uses rollers as the cathode material in contact with the conductive areas of the solar cell, or utilizes rollers carrying liquid to contact the conductive areas of the solar cell. For example, CN105590987A uses an electrolyte solution as the conductive medium to avoid hard contact. The difference between these two methods is that it is difficult for the roller itself to contact the solar cell surface where an opening is formed under a mask of a certain thickness. The conductivity of ionic liquids can overcome this drawback. However, ionic liquids can form local galvanic cells with the solar cell surface, which can cause back etching of the surface metal of the solar cell when no current is applied. This makes it difficult to control the uniformity of electroplating and poses a certain reliability risk to the electrical performance of the solar cell. When using rollers as the conductive cathode in contact with the solar cell, a plating layer also forms on the rollers. Therefore, the rollers need to be periodically deplated, requiring downtime during normal production and thus affecting equipment uptime and capacity.

[0005] The above background information is provided only to aid in understanding the inventive concept and technical solution of this patent application. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed before the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0006] The purpose of this invention is to provide a novel method for horizontal electroplating of battery cells to solve one or more problems of the prior art.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a method for horizontal electroplating of battery cells, wherein a mask opening is provided on the plated surface of the battery cell, and a flexible conductive element is fixedly attached to the mask opening, so that an electrical connection is formed between the flexible conductive element and the battery cell.

[0008] Preferably, the battery cell has a conductive material layer that is exposed through the mask opening, and the flexible conductive element is connected to the conductive material layer at the mask opening.

[0009] Furthermore, a mask opening node is provided at the mask opening, and the flexible conductive element is fixedly attached to the mask opening node and forms an electrical connection between the mask opening node and the conductive material layer.

[0010] Preferably, the mask opening is immersed in the electroplating solution, the electroplating anode is in contact with or immersed in the electroplating solution, the flexible conductive element has a first end and a second end, the first end is fixedly attached to the mask opening, the second end is electrically connected to the negative terminal of an external power supply, and the positive terminal of the external power supply is electrically connected to the electroplating anode.

[0011] Furthermore, the battery cell is horizontally arranged, the flexible conductive element is bent along its length, and the second end is higher than the first end and located above the surface of the electroplating solution in the vertical direction.

[0012] Furthermore, the negative terminal of the external power supply is electrically connected to a conductive connector, and the second end is electrically connected to the conductive connector and forms an electrical connection with the negative terminal of the external power supply through the conductive connector.

[0013] In some embodiments, the battery cell is conveyed sequentially through a surface treatment tank, an electroplating tank, and a washing tank. During the process of conveying the battery cell through the electroplating tank, the flexible conductive element and the conductive connector move in the same direction and at the same speed as the battery cell.

[0014] In some embodiments, the conductive connector is an attachment frame, and the second end is fixedly attached to the attachment frame; or, the conductive connector is a gripper, and the second end is fixedly held by the gripper.

[0015] In some embodiments, after electroplating is completed, the flexible conductive element is first cut, dividing it into a first part connected to the battery cell and a second part connected to the conductive connector.

[0016] The battery cell is vacuum-adsorbed, and force is applied to the flexible conductive element in the opposite direction to the direction in which the flexible conductive element is attached to the mask opening, so that the first part is separated from the battery cell;

[0017] And / or, the second part may be separated from the conductive connector by brushing or chemical peeling.

[0018] In some embodiments, after electroplating is completed, the connection between the conductive connector and the second end is first disconnected, then the battery cell is vacuum-adsorbed, and force is applied to the flexible conductive element in the opposite direction to the direction in which the flexible conductive element is attached to the mask opening, so that the flexible conductive element is separated from the battery cell.

[0019] In some embodiments, the flexible conductive element is in the form of a strip or a line, with the first end and the second end portion located at opposite ends along the length of the flexible conductive element.

[0020] Preferably, the surface to be plated has a plurality of mask openings, and some or all of the plurality of mask openings are respectively fixedly attached to the flexible conductive element.

[0021] Preferably, the battery cell is placed horizontally, and the battery cell has an upward-facing front side and a downward-facing back side. The front side and / or the back side is the plated surface, and each plated surface is provided with the mask opening and connected to the flexible conductive element.

[0022] Furthermore, both the front and back sides are the plating surfaces. The mask opening is provided with mask opening nodes. The flexible conductive element is fixedly attached to the mask opening nodes and forms an electrical connection with the battery cell at the mask opening nodes. Specifically, the mask opening nodes on the front side of the battery cell that are actually connected to the flexible conductive element are called the first mask opening nodes, and the mask opening nodes on the back side of the battery cell that are actually connected to the flexible conductive element are called the second mask opening nodes. The first and second mask opening nodes are located near the same side of the battery cell, and this same side extends along the transport direction of the battery cell. Alternatively, the first and second mask opening nodes are located near two opposite sides of the battery cell, and both opposite sides extend along the transport direction of the battery cell.

[0023] In some embodiments, the first mask opening node and the second mask opening node are arranged at intervals on the orthographic projection of the front side of the battery cell, or the first mask opening node and the second mask opening node are arranged at intervals on the orthographic projection of the back side of the battery cell.

[0024] In some embodiments, the sum of the number of the first mask opening node and the number of the second mask opening node is greater than 3, and the number of the first mask opening node and the number of the second mask opening node are both greater than 0. The orthographic projections of the first mask opening node and the second mask opening node on the front side of the battery cell are staggered.

[0025] Preferably, the flexible conductive element is bonded to the opening of the mask to form an electrical connection with the battery cell.

[0026] In some embodiments, the flexible conductive element has a conductor layer along its thickness direction and a conductive adhesive layer disposed on one side of the conductor layer, the conductive adhesive layer being bonded to the mask opening.

[0027] In some embodiments, the conductor material of the conductor layer is an alloy material composed of one or more of copper, aluminum, nickel and stainless steel, or the conductor layer is a multilayer structure formed by stacking multiple of copper, aluminum, nickel and stainless steel along the thickness direction; and / or, the conductive adhesive layer is a conductive pressure-sensitive adhesive layer, a conductive thermosensitive adhesive layer or a non-woven conductive adhesive layer.

[0028] In some embodiments, the flexible conductive element further includes a first coating layer disposed on the other side of the conductor layer, wherein the first coating layer is an insulating film layer or a hydrophobic film layer.

[0029] In some embodiments, the flexible conductive element further includes a second coating layer disposed outside the conductive adhesive layer. The second coating layer is an insulating film layer or a hydrophobic film layer, and along the length extension direction of the flexible conductive element, the second coating layer covers the middle part of the conductive adhesive layer, and both ends of the conductive adhesive layer are exposed.

[0030] A second objective of this invention is to provide a horizontal electroplating apparatus for battery cells.

[0031] To achieve the above objectives, the technical solution adopted by the present invention is: a horizontal electroplating apparatus for battery cells, the electroplating apparatus comprising an electroplating tank for holding an electroplating solution, an electroplating anode in contact with or immersed in the electroplating solution, and an external power supply, wherein a mask opening is provided on the plated surface of the battery cell; in the working state, a first end of a flexible conductive element is fixedly attached to the mask opening, the negative terminal of the external power supply is electrically connected to the second end of the flexible conductive element, and the positive terminal of the external power supply is electrically connected to the electroplating anode.

[0032] Preferably, the battery cell is arranged horizontally, the flexible conductive element is bent along its length, and the second end is higher than the first end and located above the surface of the electroplating solution in the vertical direction.

[0033] In some embodiments, the flexible conductive element is in the form of a strip or a line, with the first end and the second end portion located at opposite ends along the length of the flexible conductive element.

[0034] In some embodiments, the flexible conductive element has a conductor layer along its thickness direction and a conductive adhesive layer disposed on one side of the conductor layer, the conductive adhesive layer being bonded to the mask opening.

[0035] In some embodiments, the flexible conductive element further includes a first coating layer disposed on the other side of the conductor layer, wherein the first coating layer is an insulating film layer or a hydrophobic film layer.

[0036] In some embodiments, the flexible conductive element further has a second coating layer disposed outside the conductive adhesive layer, the second coating layer being an insulating film layer or a hydrophobic film layer, and the conductive adhesive layer being exposed at least at the first end.

[0037] In some embodiments, the electroplating apparatus further includes a conductive connector located outside the electroplating tank, the negative terminal of the external power supply is electrically connected to the conductive connector, and the second end of the flexible conductive member is fixedly connected to the conductive connector and forms an electrical connection with the conductive connector.

[0038] In some embodiments, the conductive connector is an attachment frame, and the second end is fixedly attached to the attachment frame; or, the conductive connector is a gripper, and the second end is fixedly held by the gripper.

[0039] In some embodiments, the electroplating apparatus further includes a transmission mechanism capable of synchronously transmitting the battery cell and the conductive connector. The transmission mechanism includes a transmission track and a roller mechanism for transmitting the battery cell, and the conductive connector is fixedly disposed on the transmission track.

[0040] In some embodiments, the electroplating tank is provided with an overflow port, and the electroplating apparatus further includes an electroplating solution spraying system, which includes at least a spray nozzle for conveying electroplating solution to the electroplating tank. Preferably, the outlet of the spray nozzle is located above the electroplating tank or inside the electroplating tank.

[0041] In some embodiments, the electroplating apparatus further includes a circulation mechanism disposed on the electroplating tank and used for circulating the electroplating solution in the electroplating tank. The circulation mechanism includes a second circulation component for circulating the electroplating solution in the lower part of the electroplating tank to the upper part of the electroplating tank, and / or a third circulation component for circulating the electroplating solution in the upper part of the electroplating tank to the lower part of the electroplating tank, and / or a first circulation component for circulating the electroplating solution in the lower part of the electroplating tank.

[0042] In some embodiments, the first circulation assembly includes a first circulation pipe and a first circulation pump disposed on the first circulation pipe. Both ends of the first circulation pipe are connected to the bottom wall of the electroplating tank, or both ends of the first circulation pipe are connected to the lower side wall of the electroplating tank, or both ends of the first circulation pipe are respectively connected to the bottom wall of the electroplating tank and the lower side wall of the electroplating tank.

[0043] In some embodiments, the second circulation assembly includes a second circulation pipe, one end of which is connected to the bottom wall of the electroplating tank or the lower side wall of the electroplating tank, and the other end of which is connected to the upper side wall of the electroplating tank or located above the opening of the electroplating tank. The second circulation assembly also includes a second circulation pump disposed on the second circulation pipe, the second circulation pump being used to drive the electroplating solution to flow from bottom to top along the second circulation pipe.

[0044] In some embodiments, the electroplating tank includes an electroplating reaction tank and a circulating replenishment tank located below the electroplating reaction tank. The circulating replenishment tank and the electroplating reaction tank may be interconnected or not interconnected. The third circulation assembly includes a third circulation pipe connected between the electroplating reaction tank and the circulating replenishment tank. When the cavity of the electroplating reaction tank and the cavity of the circulating replenishment tank are interconnected, the third circulation assembly further includes a third circulation pump disposed on the third circulation pipe and used to drive the electroplating solution to flow from top to bottom along the third circulation pipe.

[0045] In some embodiments, the electroplating tank includes an electroplating reaction tank and a circulating replenishment tank stacked on top of each other, wherein the electroplating reaction tank is configured to overflow into the circulating replenishment tank in one direction.

[0046] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: The technical solution of the embodiments of the present invention can realize the electroplating of metal materials in the mask openings on one or both sides of the battery cell, wherein the mask openings of the battery cell are connected by flexible conductive elements, avoiding the problem of cell cracking or fragmentation caused by hard conductive points clamping the battery cell in the prior art. After electroplating, a predetermined force is applied to detach the flexible conductive elements from the battery cell. After electroplating, there is no need to perform deplating treatment on the flexible conductive elements, saving deplating time and improving the production efficiency of the electroplating equipment. Attached Figure Description

[0047] Appendix Figure 1 This is a cross-sectional schematic diagram of the flexible conductive element in the first embodiment of the present invention;

[0048] Appendix Figure 2 This is a cross-sectional schematic diagram of the flexible conductive element in the second embodiment of the present invention;

[0049] Appendix Figure 3 This is a cross-sectional schematic diagram of the flexible conductive element in the third embodiment of the present invention;

[0050] Appendix Figure 4 This is a schematic diagram of the flexible conductive element in the third embodiment being cut along its length.

[0051] Appendix Figure 5 This is a schematic diagram of a flexible conductive element attached to multiple mask openings on one side of the battery cell's plating surface in the fourth embodiment of the present invention;

[0052] Appendix Figure 6 This is a schematic diagram of the flexible conductive element being attached to the two plating surfaces of the battery cell in the fifth embodiment of the present invention;

[0053] Appendix Figure 7 This is a schematic diagram of the flexible conductive element being attached to the plating surfaces on both sides of the battery cell in the fifth embodiment of the present invention.

[0054] Appendix Figure 8 In order to be in Figure 7 A schematic diagram of the flexible conductive component after bending, based on the above.

[0055] Appendix Figure 9 For the appendix Figure 8 Based on this, a schematic diagram of the battery cells supported on the roller mechanism;

[0056] Appendix Figure 10 This is a schematic diagram showing a flexible conductive component attached to the two sides of the battery cell in another way and supported on the lower roller.

[0057] Appendix Figure 11 This is a schematic diagram of the distribution of mask openings and mask opening nodes on the coating surface of a battery cell in a specific embodiment;

[0058] Appendix Figure 12 This is a schematic diagram of the cross-sectional structure of a battery cell in a specific embodiment;

[0059] Appendix Figure 13 For the appendix Figure 12 Enlarged diagram of section A in the middle;

[0060] Appendix Figure 14 A schematic diagram showing the attachment direction when a flexible conductive component is attached to a battery cell;

[0061] Appendix Figure 15 This is a schematic diagram showing the direction of force applied when the flexible conductive component separates from the battery cell after electroplating.

[0062] Appendix Figure 16 This is a schematic diagram of the principle structure of the electroplating apparatus in the fifth embodiment of the present invention;

[0063] Appendix Figure 17 This is a schematic diagram of the electroplating tank in the fifth embodiment of the present invention;

[0064] Wherein: 1. Flexible conductive component; 11. Conductor layer; 12. Conductive adhesive layer; 13. First coating layer; 14. Second coating layer; 12a. First attachment area; 12b. Second attachment area; 1A. First end; 1B. Second end; 2. Battery cell; 21. Battery cell body; 210. Semiconductor structure layer; 211. Conductive material layer; 211a. ITO layer; 211b. Seed layer; 22. Mask layer; 23. Mask opening; 231. Mask opening node; 232. Mask opening Bottom; 233, Mask opening sidewall; 234, Mask opening edge; 3, External power supply; 4, Electroplating tank; 41, Electroplating reaction tank; 42, Circulation replenishment tank; 43, First circulation pipe; 44, First circulation pump; 45, Second circulation pipe; 46, Second circulation pump; 47, Third circulation pipe; 4a, Buffer tank; 4b, Battery cell channel; 5, Electroplating anode; 6, Conductive connector; 7, Roller mechanism; 71, Lower roller; 72, Upper roller; 8, Transmission track; 9, Conductor busbar. Detailed Implementation

[0065] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0066] This invention discloses a method for horizontal electroplating of a battery cell. In this method, a mask layer 22 on the surface to be plated of the battery cell 2 is first patterned with openings to form mask openings 23 on the surface to be plated. The battery cell 2 with the mask openings 23 on its surface then undergoes electroplating to form metal grid lines on the surface to be plated. The surface to be plated refers to the surface of the battery cell 2 where the metal grid lines are to be formed by the electroplating process; either side of the surface on either side of the battery cell 2 in the thickness direction can be the surface to be plated. The patterned opening process refers to forming mask openings 23 on the mask layer 22 of the battery cell 2, such that the mask layer 22 with the mask openings 23 forms a predetermined pattern.

[0067] During the electroplating process of the battery cell 2, a flexible conductive element 1 is used and is fixedly attached to the mask opening 23, thereby forming an electrical connection between the flexible conductive element 1 and the battery cell 2 during the electroplating process. The flexible conductive element 1 is fixedly attached to the mask opening 23, and the fixed connection can be achieved by means such as adhesive, magnetic adsorption, or snap-fit. In this application, adhesive is preferred to facilitate the rapid connection or detachment of the flexible conductive element 1 from the mask opening 23 of the battery cell 2.

[0068] See Figures 12 to 13As shown, the mask opening 23 includes a mask opening bottom 232, a mask opening sidewall 233, and a mask opening edge 234. The flexible conductive element 1 is fixedly attached to the mask opening 23, which means that the flexible conductive element 1 is fixedly attached to the mask opening bottom 232, the mask opening sidewall 233, or the mask opening edge 234, or the flexible conductive element 1 is fixedly attached to any two or three of the mask opening bottom 232, the mask opening sidewall 233, and the mask opening edge 234.

[0069] The electrical connection here specifically refers to a connection between at least two conductors through physical contact. For details, see [link to relevant documentation]. Figure 12 As shown, the battery cell 2 includes a battery cell body 21, which includes a semiconductor structure layer 210 and a conductive material layer 211 disposed on the surface of the semiconductor structure layer 210. The conductive material layer 211 includes at least an ITO (Indium Tin Oxide) layer 211a. In some embodiments, the conductive material layer 211 also includes a seed layer 211b covering the ITO layer 211a. The seed layer 211b is specifically a conductive structure layer pre-set for the preparation of the gate line. After the gate line preparation is completed, the portion of the seed layer 211b except for the part below the gate line needs to be removed to expose the ITO layer 211a.

[0070] Both the seed layer 211b and the ITO layer 211a are conductive. The mask layer 22 covers the conductive material layer 211, and the conductive material layer 211 is exposed from the mask opening 23. The exposed portion forms the bottom 232 of the mask opening. The flexible conductive element 1 is fixedly attached to the mask opening 23, so that the flexible conductive element 1 directly contacts the conductive material layer 211 to form an electrical connection, or forms an electrical connection through the electroplating solution after being immersed in the electroplating solution. In this embodiment, when the flexible conductive element 1 is fixedly attached to the mask opening 23, it directly contacts the conductive material layer 211 to form an electrical connection, so as to ensure that the current after energization is not too small, thus increasing the electroplating time. Specifically, see Figure 11 As shown, the mask opening 23 includes a mask opening node 231, and the flexible conductive element 1 is fixedly attached to the mask opening node 231, thereby achieving direct contact with the conductive material layer 211 and thus forming an electrical connection with the battery cell 2.

[0071] In other embodiments, when the flexible conductive element 1 is fixedly attached to the mask opening 23, the flexible conductive element 1 can be connected to the edge 234 of the mask opening. Both the flexible conductive element 1 and the mask layer 22 are immersed in the electroplating solution, and the electrical connection between the flexible conductive element 1 and the bottom 232 of the mask opening is achieved through the conductivity of the electroplating solution. When the size of the flexible conductive element 1 is small, the flexible conductive element 1 can also be connected to the bottom 232 of the mask opening or the sidewall 233 of the mask opening. These solutions eliminate the need for additional mask opening nodes 231, making the structure of the mask opening 23 simpler.

[0072] It should be noted that the mask opening node 231 mentioned above is an area for the flexible conductive component 1 to be fixedly attached and connected, and is an area with a certain cross-sectional area.

[0073] The shape of the flexible conductive element 1 is not limited in this application; it can be strip-shaped or line-shaped, bar-shaped or block-shaped, and can be regular or irregular in shape. The flexible conductive element 1 has a first end 1A and a second end 1B, see [reference needed]. Figure 16 As shown, during the electroplating process of the battery cell 2, the mask opening 23 of the battery cell 2 is immersed in the electroplating solution, the electroplating anode 5 is in contact with or immersed in the electroplating solution, the first end 1A of the flexible conductive element 1 is fixedly attached to the mask opening 23 of the surface of the battery cell 2 to be plated, the second end 1B of the flexible conductive element 1 is electrically connected to the negative terminal of the external power supply 3, and the positive terminal of the external power supply 3 is electrically connected to the electroplating anode 5. Specifically, the negative terminal of the external power supply 3 is electrically connected to the conductive connector 6, and the aforementioned second end 1B of the flexible conductive element 1 is electrically connected to the conductive connector 6, thereby achieving an electrical connection between the flexible conductive element 1 and the negative terminal of the external power supply 3 through the conductive connector 6. In this way, the flexible conductive element 1 achieves an electrical connection between the negative terminal of the external power supply 3 and the battery cell 2, avoiding the microcrack problem that may be caused by the rigid conductive points clamping the battery cell in the prior art. After electroplating is completed, a predetermined force is applied to peel off the flexible conductive part 1, which is fixedly attached to the mask opening of the battery cell. This completes the separation of the flexible conductive part 1 from the battery cell 2. No deplating treatment is required on the flexible conductive part 1 after electroplating, saving deplating time and improving the production efficiency of the electroplating equipment. The area on the flexible conductive part 1 that connects to the battery cell 2 is also electroplated, but the flexible conductive part 1 has a low cost and can be used as a consumable. The peeled-off flexible conductive part 1 is directly treated as waste and does not require deplating.

[0074] It should be noted that the term "flexibility" in this application can also be interpreted as flexurality, a property of an object relative to rigidity. Flexibility refers to the physical property of an object that deforms under force and cannot return to its original shape after the force is removed. In contrast, a rigid object, when subjected to force, can be considered to have no change in shape from a macroscopic perspective. For example, in this application, to facilitate the connection of the flexible conductive element 1 to the battery cell 2, an external force is used to bend the first end 1A of the flexible conductive element 1 to form a bent portion, thus changing the shape of the flexible conductive element 1. If no external force is applied, the shape of the flexible conductive element 1 will not return to its original shape, and the bent portion will not disappear.

[0075] In this embodiment of the invention, the flexible conductive element 1 is bonded to the mask opening 23 on the plating surface of the battery cell 2 to form an electrical connection with the battery cell 2, and is also bonded to the conductive connector 6 to form an electrical connection with the conductive connector 6, thereby further achieving an electrical connection with the negative terminal of the external power supply 3. That is, the conductive connector 6 is specifically an attachment frame, and the flexible conductive element 1 is fixed to the mask opening 23 of the battery cell 2 and to the conductive connector 6 by bonding. Figures 1 to 3 Schematic diagrams of different embodiments of the flexible conductive element 1 are shown.

[0076] See Figure 1 The diagram shows a schematic of the flexible conductive element 1 according to the first embodiment. The flexible conductive element 1 has a conductor layer 11 and a conductive adhesive layer 12 disposed on one side of the conductor layer 11 along its thickness direction. Both the conductor layer 11 and the conductive adhesive layer 12 are conductors. The side of the conductive adhesive layer 12 facing away from the conductor layer 11 is adhesive, allowing it to be fixedly bonded to the mask opening 23. The conductive adhesive layer 12 is fixedly bonded to the mask opening 23 of the battery cell 2, thereby achieving an electrical connection with the battery cell 2. The conductor material of the conductor layer 11 is one or an alloy of any two or more of copper, aluminum, nickel, and stainless steel, or a multilayer structure formed by stacking multiple materials of copper, aluminum, nickel, and stainless steel along the thickness direction. The conductive adhesive layer 12 is a conductive pressure-sensitive adhesive layer, a conductive heat-sensitive adhesive layer, or a non-woven conductive adhesive layer. The conductive adhesive layer 12 provides conductivity at least from the conductor layer 11 to the conductive adhesive layer 12. When electrically connecting the flexible conductive component 1 to the battery cell 2 and the conductive connector 6, the conductive adhesive layer 12 can be directly bonded to the battery cell 2 and the conductive connector 6, making the bonding operation simple.

[0077] See Figure 2The diagram shows a schematic of the flexible conductive element 1 according to the second embodiment. Based on the first embodiment, the flexible conductive element 1 further includes a first coating layer 13 disposed on the other side of the conductor layer 11. This first coating layer 13 is an insulating film or a hydrophobic film, used to insulate or isolate this side of the conductor layer 11 from the electroplating solution that the flexible conductive element 1 may come into contact with, thereby reducing the electroplating area and preventing the surface of the conductor layer 11 from being plated. Specifically, the dimensions and shape of the surfaces of the first coating layer 13 that cooperate with the flexible conductive element 1 are the same, so that the entire surface of the conductor layer 11 on the other side is covered by the first coating layer 13.

[0078] See Figure 3 The diagram shows a schematic of the flexible conductive element 1 according to the third embodiment. Based on the second embodiment, this flexible conductive element 1 further includes a second coating layer 14 disposed on the outer surface of the conductive adhesive layer 12. This second coating layer 14 is also an insulating or hydrophobic film layer, used to insulate or isolate the outer surface of the conductive adhesive layer 12 from the electroplating solution that the flexible conductive element 1 may come into contact with, thereby reducing the electroplating area. This also makes the surface of the entire flexible conductive element 1 corrosion-resistant and provides better conductivity internally. The outer surface of the conductive adhesive layer 12 is not completely covered by the second coating layer 14, leaving at least the first end 1A exposed for adhesion to the mask opening 23. Figure 3 As shown in Figure a, in this embodiment, the second coating layer 14 covers the middle of the conductive adhesive layer 12, and the two ends of the conductive adhesive layer 12 are exposed to form the first attachment region 12a and the second attachment region 12b, respectively. Figure 3 As shown in Figure b, the conductive adhesive layer 12 is only exposed at the first end 1A, and the conductive adhesive layer 12 does not cover the second end 1B. The second end 1B of the flexible conductive member 1 is electrically connected to the conductive connector 6 through the conductor layer 11. It should be noted that the side of the conductive adhesive layer 12 that is in contact with the conductor layer 11 is the inner side of the conductive adhesive layer 12, and the side opposite to the inner side of the conductive adhesive layer 12 is the outer side.

[0079] Preferably, the flexible conductive element 1 has a thickness of not less than 5 μm and a length that can be a pre-cut length cut in segments or a continuous structure arranged in a roll (referred to as flexible conductive element roll) that can be wound onto a reel. When the flexible conductive element roll is used in electroplating, it can be unwound according to the required length, and then refer to... Figure 4The material is cut as shown and then bonded to the mask opening 23 of the battery cell 2. During the cutting process, a vision system can be used to identify the cutting position and perform error correction. This reduces the plating area from the conductive adhesive layer 12, leaving the conductive adhesive layer to form the first attachment area 12a and the second attachment area 12b, which are then bonded to the battery cell 2 and the conductive connector 6 respectively to form an electrical connection. When a cutting misalignment occurs, the vision system can correct the cutting position, preventing the ends of the flexible conductive member 1 connecting the battery cell 2 and the conductive connector 6 from being too short.

[0080] During electroplating, the battery cell 2 is set horizontally, and the flexible conductive member 1 is bent along the length direction, so that the second end 1B is higher than the first end 1A in the vertical direction. The second end 1B is located above the surface of the electroplating solution and is attached to the conductive connector 6.

[0081] In some other embodiments, the conductive connector 6 is specifically a gripper, with the second end 1B fixedly held by the gripper and forming an electrical connection with it. That is, the first end 1A is bonded to the mask opening 23 of the battery cell 2 via the first attachment area 12a, thus forming an electrical connection with the battery cell 2. The second end 1B is held by the gripper, and the electrical connection between the flexible conductive element 1 and the gripper is achieved through the contact between the second attachment area 12b and the gripper. In other embodiments, the second end 1B does not have a second attachment area 12b, and the gripper directly clamps onto the conductor layer 11. This gripping by the gripper allows for a more stable connection, reducing the probability of the flexible conductive element 1 detaching from the conductive connector 6. Of course, the specific form of the conductive connector 6 is not limited to the attachment frame or gripper listed above.

[0082] During electroplating, the battery cell 2 is placed horizontally. The surface of the battery cell 2 facing upward is the front side, and the surface of the battery cell 2 facing downward is the back side. One or both of the front and back sides are the plating surface, and each plating surface is provided with a mask opening 23.

[0083] See Figure 11As shown, multiple mask openings 23 are arranged side-by-side on the plating surface of the solar cell 2, and all or part of the mask openings 23 are interconnected to form one or more connected patterns. The bottom of each mask opening 23 is a conductive material layer 211, specifically a conductive seed layer 211b or an ITO layer 211a. Even if the mask openings 23 are not interconnected, they can still be electrically connected through the bottom conductive material layer 211. That is, only the bottom conductive material layer 211 of one mask opening 23 needs to be conductive for the other mask openings 23 to conduct electricity. At least one flexible conductive element 1 is connected to one plating surface of the solar cell 2 to electroplate metal material in the multiple mask openings 23 to form grid lines. To improve the electroplating speed, all or part of each of the multiple mask openings 23 is connected to a flexible conductive element 1. Preferably, when there are multiple flexible conductive elements 1, the connection points between the flexible conductive elements 1 and the mask opening 23 are equally spaced, so that the plated surface of the battery cell 2 is uniformly conductive, thereby improving the electroplating uniformity of the plated surface of the battery cell 2.

[0084] See Figure 11 As shown, the mask opening 23 is divided into vertical opening, horizontal opening, and annular opening. The mask opening node 231 is located at the intersection of the vertical opening, horizontal opening, and annular opening. The area of ​​the mask opening node 231 is enlarged to facilitate the connection of the flexible conductive strip 1, which is convenient for machine vision guidance during bonding. After enlarging the area of ​​the mask opening node 231, the flexible conductive element 1 can be directly connected to the conductive material layer 211 at the bottom of the mask opening node 231, achieving a larger area of ​​electrical connection, increasing the electroplating current, and thus improving the electroplating efficiency.

[0085] See Figure 5 As shown, when one of the front or back surfaces of the battery cell 2 is the plating surface, at least two of the mask openings 23 on the plating surface are respectively connected to flexible conductive elements 1. The flexible conductive elements 1 are arranged side by side and can be connected by a conductor bus 9, which is then fixedly connected to the conductive connector 6. Of course, the flexible conductive elements 1 can also be directly connected to the conductive connector 6. In some embodiments, the conductor bus 9 and the conductive connector 6 can also be integrally formed.

[0086] When both the front and back sides of the battery cell 2 are the plating surfaces, at least two of the mask openings 23 on the front side of the battery cell 2 are respectively connected to flexible conductive elements 1, and at least two of the mask openings 23 on the back side of the battery cell 2 are respectively connected to flexible conductive elements 1. These flexible conductive elements 1 are all connected to the conductor busbar 9 or directly connected to the conductive connector 6.

[0087] Preferably, the mask opening node 231 on the front side of the battery cell 2 that is actually connected to the flexible conductive element 1 is called the first mask opening node; the mask opening node 231 on the back side of the battery cell 2 that is actually connected to the flexible conductive element 1 is called the second mask opening node. More preferably, the first mask opening node and the second mask opening node are disposed on the same side of the battery cell 2, and this same side extends along the transmission direction of the battery cell, such as... Figure 6 and Figure 9 As shown.

[0088] More preferably, the first mask opening node and the second mask opening node are spaced apart on the front side of the battery cell 2, or the first mask opening node and the second mask opening node are spaced apart on the back side of the battery cell 2. When the flexible conductive element 1 connected to the second mask opening node is bent and extended to the front side of the battery cell 2, the flexible conductive element 1 connected to the first mask opening node will not interfere with the flexible conductive element 1 connected to the second mask opening node, making it convenient for all the flexible conductive elements 1 to be connected to the conductor busbar 9 or the conductive connector 6. More preferably, the sum of the number of the first mask opening nodes and the number of the second mask opening nodes is greater than 3, and the number of the first mask opening nodes and the number of the second mask opening nodes are both not 0. The orthographic projections of the first mask opening nodes and the second mask opening nodes on the front side of the battery cell 2 are staggered. When the flexible conductive element 1 connecting the second mask opening node is bent and extended to the front side of the battery cell 2, the flexible conductive element 1 connecting the first mask opening node will not interfere with the flexible conductive element 1 connecting the second mask opening node. This facilitates the connection of all the flexible conductive elements 1 to the conductor busbar 9 or the conductive connector 6. At the same time, it allows the first mask opening nodes to be spaced apart when there are multiple first mask opening nodes, and the second mask opening nodes to be spaced apart when there are multiple second mask opening nodes, thereby improving the electroplating uniformity of the battery cell 2.

[0089] In some other embodiments, such as Figure 10 As shown, the first mask opening node and the second mask opening node can also be positioned close to two opposite sides of the battery cell 2, with both opposite sides extending along the transport direction of the battery cell 2, such as... Figure 10 As shown.

[0090] During the electroplating process, the battery cell 2 is conveyed and sequentially passes through a surface treatment tank, an electroplating tank, a washing tank, and a drying tank for corresponding processing. During the conveyance of the battery cell 2 through the electroplating tank, the flexible conductive element 1 is always connected between the battery cell 2 and the conductive connector 6. The flexible conductive element 1, the conductive connector 6, and the battery cell 2 move in the same direction and at the same speed. Specifically: the surface treatment tank is an acid pickling tank, mainly used to remove impurities from the surface of the battery cell 2 in preparation for subsequent electroplating; the electroplating tank is used to electroplat metal at the mask opening 23 of the battery cell 2. Preferably, the electroplating tank includes a copper plating tank and a tin plating tank. The battery cell 2 is first electroplated in the copper plating tank to form copper grid lines, and then a tin plating layer is electroplated on the surface of the copper grid lines in the tin plating tank. Thus, immediately after copper plating, tin plating is applied to the surface of the copper grid lines to prevent oxidation and protect them. A water washing tank is used to clean the battery cells 2, removing impurities and residual plating solution from their surface. This can be done by spraying or immersion washing. A drying tank is used to blow air onto the surface of the battery cells 2, reducing the amount of liquid on their surface. This drying tank is located downstream of the electroplating tank. Preferably, the drying tank includes an air knife mechanism that blows air onto the battery cells 2 to reduce the amount of liquid on their surface.

[0091] During the electroplating process, a transfer mechanism synchronously transports the battery cells 2 and the conductive connectors 6. Specifically, the transfer mechanism includes a transfer track 8 for transporting the battery cells 2 and a roller mechanism 7 for transporting the battery cells 2. The conductive connectors 6 are fixedly mounted on the transfer track 8 and transported by the transfer track 8. In operation, a drive unit drives the transfer track 8 to move, causing the conductive connectors 6 and the flexible conductive element 1 connected thereto to move along the transport direction of the battery cells 2, so that the flexible conductive element 1 and the battery cells 2 connected to it move at the same speed and in the same direction. In some embodiments, the roller mechanism 7 only includes a lower roller 71, such as... Figure 10 As shown, during transmission, the lower roller 71 provides support for the battery cell 2, which moves forward under the tension of the flexible conductive element 1. In other embodiments, the roller mechanism 7 includes an upper roller 72 and a lower roller 71 that cooperate with each other, such as... Figure 9 and Figure 16As shown, the upper roller 72 and the lower roller 71 cooperate to transfer the battery cell 2. In this configuration, the lower roller 71 is fully immersed in the electroplating solution, while the upper roller 72 is partially immersed, ensuring that the battery cell 2 is completely submerged. The electroplating anode 5 is located between two adjacent sets of upper rollers 72 and / or two adjacent sets of lower rollers 71, and is positioned opposite to the plating surface of the battery cell 2, ensuring that the electroplating anode 5 is at least partially immersed in the electroplating solution to achieve the electroplating function. In other embodiments, only the back side of the battery cell 2 is electroplated; the lower roller 71 is fully immersed in the electroplating solution, while the upper roller 72 may not be immersed, as long as the back side of the battery cell 2 is completely submerged.

[0092] After electroplating, the flexible conductive element 1 is detached from the battery cell 2 and the conductive connector 6. This can be done by the following steps: First, cut the flexible conductive element 1, dividing it into a first part connected to the battery cell 2 (first end 1A is located in this first part) and a second part connected to the conductive connector 6 (second end 1B is located in this second part). Then, separate the first part from the battery cell 2 and the second part from the conductive connector 6. When separating the first part from the battery cell 2, preferably, the battery cell 2 can be vacuum-adsorbed, and force is applied in the opposite direction to the direction in which the flexible conductive element 1 is bonded to the mask opening 23. Figure 15 As shown, this allows the first part to separate from the battery cell 2. When separating the second part from the conductive connector 6, it can be done by brushing or chemical peeling. Brushing involves repeatedly wiping the connection between the second part and the conductive connector 6 with a brush until the second part detaches. After detachment, the connection can be further wiped with a brush to remove any remaining residue. Chemical peeling involves soaking the connection between the second part and the conductive connector 6 in an adhesive remover or alkaline solution until the second part falls off, simultaneously removing any remaining residue.

[0093] In some other embodiments, when the conductive connector 6 is a gripper, the second end 1B of the flexible conductive member 1 is held by the gripper. After electroplating is completed, the gripper releases the second end 1B, so there is no need to cut the flexible conductive member 1. At this time, after the gripper releases the second end 1B, the first end 1A can be separated from the battery cell 2.

[0094] See Figure 16As shown, the electroplating apparatus for horizontal electroplating also includes an electroplating tank 4 for holding the electroplating solution. The electroplating anode 5 and the roller mechanism 7 are both located in the electroplating tank 4. The conductive connector 6 is located above the electroplating tank 4, and the external power supply 3 is located outside the electroplating tank 4. The electroplating tank 4 has a battery cell channel 4b for the battery cell 2 to enter the electroplating tank 4 along the transmission direction. Buffer tanks 4a are provided upstream and downstream of the electroplating tank 4, and the liquid in the electroplating tank 4 can overflow into the buffer tank 4a. The electroplating apparatus also includes an electroplating solution spraying system (not shown in the figure). The electroplating solution spraying system includes at least a spray pipe. The outlet of the spray pipe is located above the electroplating tank 4. During the electroplating process, the electroplating solution spraying system can spray electroplating solution into the electroplating tank 4 to achieve the purpose of replenishing the solution. The concentration of the electroplating solution in the electroplating tank 4 is ensured by overflow and spray replenishment, while the flow of the electroplating solution in the electroplating tank 4 is increased, making the concentration of the electroplating solution in the electroplating tank 4 more uniform, which is conducive to the uniform electroplating of the battery cells 2.

[0095] See Figure 17 As shown, the electroplating apparatus further includes a circulation mechanism disposed on the electroplating tank 4 for circulating the electroplating solution in the electroplating tank 4. The circulation mechanism includes a second circulation component for circulating the electroplating solution in the lower part of the electroplating tank 4 to the upper part of the electroplating tank 4, and / or a third circulation component for circulating the electroplating solution in the upper part of the electroplating tank 4 to the lower part of the electroplating tank 4, and / or a first circulation component for circulating the electroplating solution in the lower part of the electroplating tank 4.

[0096] See Figure 17 As shown, in this embodiment, the first circulation component includes a first circulation pipe 43 and a first circulation pump 44 disposed on the first circulation pipe 43. Both ends of the first circulation pipe 43 are connected to the bottom wall or the lower side wall of the electroplating tank 4. Here, both ends of the first circulation pipe 43 are connected to the bottom wall of the electroplating tank 4 and communicate with the tank cavity of the electroplating tank 4. In other embodiments, both ends of the first circulation pipe 4 can be connected to the lower side wall of the electroplating tank 4, or both ends can be connected to the bottom wall and the lower side wall of the electroplating tank 4 respectively. When the first circulation pump 44 is working, it enables the electroplating solution in the lower part of the electroplating tank 4 to circulate through the first circulation pipe 43, thereby stirring the electroplating solution in the lower part of the electroplating tank 4, making the electroplating solution evenly distributed, especially making the electroplating solution in the lower part of the electroplating tank 4 evenly distributed.

[0097] In this embodiment, the second circulation component includes a second circulation pipe 45 and a second circulation pump 46. One end of the second circulation pipe 45 is connected to the bottom wall or the lower side wall of the electroplating tank 4, and the other end is connected to the upper side wall or located above the opening of the electroplating tank 4. Specifically, the lower end of the second circulation pipe 45 is connected to the bottom wall of the electroplating tank 4, and the upper end is connected to the upper side wall of the electroplating tank 4. The second circulation pump 46 drives the electroplating solution to flow upward along the second circulation pipe 45, thereby pumping the electroplating solution in the lower part of the electroplating tank 4 into the upper part of the electroplating tank 4. In this way, the electroplating solution in the upper part and the electroplating solution in the lower part of the electroplating tank 4 can be circulated, thereby agitating the electroplating solution in the entire electroplating tank 4 and making the electroplating solution evenly distributed throughout the entire electroplating tank 4.

[0098] In this embodiment, the electroplating tank 4 includes an electroplating reaction tank 41 and a circulating replenishment tank 42. The electroplating reaction tank 41 is located above the circulating replenishment tank 42, with the inner cavity of the electroplating reaction tank 41 corresponding to the upper part of the electroplating tank 4, and the inner cavity of the circulating replenishment tank 42 corresponding to the lower part of the electroplating tank 4. The battery cells 2 undergo electroplating treatment within the inner cavity of the electroplating reaction tank 41. The electroplating reaction tank 41 and the circulating replenishment tank 42 are not interconnected. The third circulation component includes a third circulation pipe 47 connected between the electroplating reaction tank 41 and the circulating replenishment tank 42. One end of the third circulation pipe 47 is connected to the upper part of the electroplating reaction tank 41, and the other end is connected to the upper part of the circulating replenishment tank 42. Under the action of gravity, the electroplating solution in the upper part of the electroplating reaction tank 41 can enter the circulating replenishment tank 42. At the same time, by continuously replenishing the electroplating solution in the electroplating reaction tank 41, the electroplating solution in the electroplating reaction tank 41 can be evenly distributed. In some other embodiments, the third circulation component may further include a third circulation pump for pumping the processing liquid in the upper part of the electroplating reaction tank 41 into the circulation replenishment tank 42. In other embodiments, when the electroplating reaction tank 41 and the circulation replenishment tank 42 arranged vertically are in communication with each other, the electroplating liquid in the upper part of the electroplating reaction tank 41 may also be pumped into the circulation replenishment tank 42 by providing a third circulation pump.

[0099] In some other embodiments, when the cavity of the electroplating reaction tank 41 and the cavity of the circulating replenishment tank 42 are not connected, the electroplating reaction tank 41 and the circulating replenishment tank 42 may not be arranged in an up-down direction. The first circulation component, the second circulation component and the third circulation component realize the corresponding circulation flow of the treatment liquid through the first circulation pump 44, the second circulation pump 46 and the third circulation pump, respectively.

[0100] In some other embodiments, no third circulation component is provided. The electroplating reaction tank 41 and the circulation replenishment tank 42 of the electroplating tank 4 are stacked on top of each other, and the electroplating reaction tank 41 is configured to overflow into the circulation replenishment tank 42 in one direction. In this way, as liquid is continuously replenished into the electroplating reaction tank 41, the electroplating liquid at the top of the electroplating reaction tank 41 overflows outward into the circulation replenishment tank 42. This also enables the electroplating liquid in the electroplating reaction tank 41 to achieve dynamic balance and uniform distribution.

[0101] The following combination Figure 16 The schematic diagram of the horizontal electroplating apparatus shown illustrates the specific implementation steps of the electroplating method in this embodiment, as well as the horizontal electroplating process performed on a battery cell 2 whose front and back sides are both plating surfaces.

[0102] (1) The mask layer 22 on the front and back of the battery cell 2 is pre-patterned and opened, and mask openings 23 are formed on both sides of the plated surface.

[0103] (2) The first end 1A of the flexible conductive element 1 is respectively bonded to the mask openings 23 on both sides of the plated surface. The flexible conductive element 1 is partially or completely connected to multiple mask openings 23 on the same side of the plated surface. The second end 1B of the flexible conductive element 1 is bonded to the conductive connector 6 and an electrical connection is formed between them. The negative terminal of the external power supply 3 is electrically connected to the conductive connector 6, and the positive terminal of the external power supply 3 is electrically connected to the two electroplating anodes 5 respectively. The upper roller 72 of the roller mechanism 7 is connected to the conductive connector 6. The lower rollers 71 cooperate with each other and are used to transport the battery cells 2. The roller mechanism 7 is located in the electroplating tank 4. The lower rollers 71 are completely immersed in the electroplating solution, and more than half of the height of the upper rollers 72 is immersed in the electroplating solution. One electroplating anode 5 is located between two adjacent lower rollers 71, and the electroplating working surface of the electroplating anode 5 faces the back of the battery cell 2. The other electroplating anode 5 is located between two adjacent upper rollers 72, and the electroplating working surface of the electroplating anode 5 faces the front of the battery cell 2. The two electroplating anodes 5 are either immersed in the electroplating solution or in contact with the electroplating solution.

[0104] (3) The transmission mechanism transmits the battery cell 2, the conductive connector 6 and the flexible conductive component 1 at the same speed and in the same direction, so that the battery cell 2 passes through the surface treatment tank, the electroplating tank, the water washing tank and the drying tank in sequence to carry out the corresponding process treatment.

[0105] (4) Cut the flexible conductive part 1 between the first end 1A and the second end 1B, then vacuum adsorb the battery cell 2, and apply force to the flexible conductive part 1 on the battery cell 2 in the opposite direction to the direction of adhesion to the battery cell 2, so that the flexible conductive part 1 is separated from the battery cell 2; use adhesive remover or alkaline solution to soak the connection between the second part and the conductive connector 6, so that the flexible conductive part 1 is detached from the conductive connector 6, and at the same time remove the residues adhering to the electrical connector 6.

[0106] During the electroplating process described above, the flexible conductive element 1 provides an electrical connection between the battery cell 2, the conductive connector 6, and the negative terminal of the external power supply 3. This enables the electroplating of metal materials in the mask opening 23 of the battery cell 2. There are no hard clamps at the connection point, avoiding the problem of cracking or fragmentation caused by hard conductive points clamping the battery cell in the prior art. After the electroplating is completed, a predetermined force is applied to the flexible conductive element 1, which is bonded to the mask opening 23 of the battery cell 2, to separate the flexible conductive element 1 from the battery cell 2. No plating removal is required, which is efficient and convenient.

[0107] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for horizontal electroplating of battery cells, characterized in that: A mask opening is provided on the plating surface of the battery cell. The mask opening includes a bottom, a sidewall, and an edge. A flexible conductive element is fixedly attached to the bottom of the mask opening, so that an electrical connection is formed between the flexible conductive element and the battery cell. The flexible conductive element is bonded to the bottom of the mask opening to form an electrical connection with the battery cell.

2. The method for horizontal electroplating of battery cells according to claim 1, characterized in that: The battery cell has a conductive material layer that is exposed through the mask opening, and the flexible conductive element is connected to the conductive material layer at the bottom of the mask opening.

3. The method for horizontal electroplating of battery cells according to claim 2, characterized in that: The bottom of the mask opening is provided with a mask opening node, and the flexible conductive element is fixedly attached to the mask opening node and forms an electrical connection between the mask opening node and the conductive material layer.

4. The method for horizontal electroplating of battery cells according to claim 1, characterized in that: The mask opening is immersed in the electroplating solution, and the electroplating anode is in contact with or immersed in the electroplating solution. The flexible conductive element has a first end and a second end. The first end is fixedly attached to the bottom of the mask opening, and the second end is electrically connected to the negative terminal of an external power supply. The positive terminal of the external power supply is electrically connected to the electroplating anode.

5. The method for horizontal electroplating of battery cells according to claim 4, characterized in that: The battery cell is horizontally arranged, the flexible conductive element is bent along its length, and the second end is higher than the first end and located above the surface of the electroplating solution in the vertical direction.

6. The method for horizontal electroplating of battery cells according to claim 4, characterized in that: The negative terminal of the external power supply is electrically connected to the conductive connector, and the second end is electrically connected to the conductive connector and forms an electrical connection with the negative terminal of the external power supply through the conductive connector.

7. The method for horizontal electroplating of battery cells according to claim 6, characterized in that: The battery cell is transported sequentially through a surface treatment tank, an electroplating tank, and a washing tank. During the process of transporting the battery cell through the electroplating tank, the flexible conductive element and the conductive connector move in the same direction and at the same speed as the battery cell.

8. The method for horizontal electroplating of battery cells according to claim 6, characterized in that: The conductive connector is an attachment frame, and the second end is fixedly attached to the attachment frame; or, the conductive connector is a gripper, and the second end is fixedly held by the gripper.

9. The method for horizontal electroplating of battery cells according to claim 6, characterized in that: After electroplating is completed, the flexible conductive component is cut into two parts: a first part connected to the battery cell and a second part connected to the conductive connector. The battery cell is vacuum-adsorbed, and force is applied to the flexible conductive element in the opposite direction to the direction in which the flexible conductive element is attached to the mask opening, so that the first part is separated from the battery cell; And / or, the second part may be separated from the conductive connector by brushing or chemical peeling.

10. The method for horizontal electroplating of battery cells according to claim 6, characterized in that: After electroplating is completed, the connection between the conductive connector and the second end is first disconnected, and then the battery cell is vacuum-adsorbed. Force is applied to the flexible conductive element in the opposite direction to the direction in which the flexible conductive element is attached to the mask opening, so that the flexible conductive element is separated from the battery cell.

11. The method for horizontal electroplating of battery cells according to claim 4, characterized in that: The flexible conductive element is strip-shaped or wire-shaped, with the first end and the second end portion located at opposite ends along the length of the flexible conductive element.

12. The method for horizontal electroplating of battery cells according to claim 1, characterized in that: The surface to be plated has a plurality of mask openings, and the flexible conductive element is fixedly attached to some or all of the plurality of mask openings.

13. The method for horizontal electroplating of battery cells according to claim 1, characterized in that: The battery cell is placed horizontally, and the battery cell has a front side facing upward and a back side facing downward. The front side and / or the back side is the plated surface. Each plated surface is provided with the mask opening and connected to the flexible conductive element.

14. The method for horizontal electroplating of battery cells according to claim 13, characterized in that: Both the front and back sides are the plating surfaces. A mask opening node is provided at the bottom of the mask opening. The flexible conductive element is fixedly attached to the mask opening node and forms an electrical connection with the battery cell at the mask opening node. The mask opening node on the front side of the battery cell that is actually connected to the flexible conductive element is called the first mask opening node, and the mask opening node on the back side of the battery cell that is actually connected to the flexible conductive element is called the second mask opening node. The first mask opening node and the second mask opening node are disposed near the same side of the battery cell, and the same side extends along the transport direction of the battery cell; or, the first mask opening node and the second mask opening node are disposed near two opposite sides of the battery cell, and the two opposite sides both extend along the transport direction of the battery cell.

15. The method for horizontal electroplating of battery cells according to claim 14, characterized in that: The first mask opening node and the second mask opening node are arranged at intervals on the front side of the battery cell, or the first mask opening node and the second mask opening node are arranged at intervals on the back side of the battery cell.

16. The method for horizontal electroplating of battery cells according to claim 14, characterized in that: The sum of the number of the first mask opening node and the number of the second mask opening node is greater than 3, and the number of the first mask opening node and the number of the second mask opening node are both greater than 0. The orthographic projections of the first mask opening node and the second mask opening node on the front side of the battery cell are staggered.

17. The method for horizontal electroplating of battery cells according to any one of claims 1 to 16, characterized in that: The flexible conductive element has a conductor layer along its thickness direction and a conductive adhesive layer disposed on one side of the conductor layer, the conductive adhesive layer being bonded to the bottom of the mask opening.

18. The method for horizontal electroplating of battery cells according to claim 17, characterized in that: The conductor material of the conductor layer is one or more alloy materials composed of copper, aluminum, nickel and stainless steel, or the conductor layer is a multilayer structure formed by stacking multiple materials of copper, aluminum, nickel and stainless steel along the thickness direction.

19. The method for horizontal electroplating of battery cells according to claim 17, characterized in that: The conductive adhesive layer is a conductive pressure-sensitive adhesive layer, a conductive thermosensitive adhesive layer, or a non-woven conductive adhesive layer.

20. The method for horizontal electroplating of battery cells according to claim 17, characterized in that: The flexible conductive element also has a first coating layer disposed on the other side of the conductor layer, wherein the first coating layer is an insulating film layer or a hydrophobic film layer.

21. The method for horizontal electroplating of battery cells according to claim 20, characterized in that: The flexible conductive element also has a second coating layer disposed on the outside of the conductive adhesive layer. The second coating layer is an insulating film layer or a hydrophobic film layer. Along the length extension direction of the flexible conductive element, the second coating layer covers the middle part of the conductive adhesive layer, and both ends of the conductive adhesive layer are exposed.

22. A horizontal electroplating apparatus for battery cells, characterized in that: The electroplating apparatus includes an electroplating tank for holding an electroplating solution, an electroplating anode that contacts or is immersed in the electroplating solution, and an external power supply. A mask opening is provided on the plating surface of the battery cell. The mask opening includes a bottom, a sidewall, and an edge. In operation, a first end of a flexible conductive element is fixedly attached to the bottom of the mask opening. The negative terminal of the external power supply is electrically connected to a second end of the flexible conductive element, and the positive terminal of the external power supply is electrically connected to the electroplating anode. The fixed attachment is an adhesive bonding, and the first end is bonded to the bottom of the mask opening to form an electrical connection with the battery cell.

23. The horizontal electroplating apparatus for battery cells according to claim 22, characterized in that: The battery cell is horizontally arranged, the flexible conductive element is bent along its length, and the second end is higher than the first end and located above the surface of the electroplating solution in the vertical direction.

24. The horizontal electroplating apparatus for battery cells according to claim 22, characterized in that: The flexible conductive element is strip-shaped or wire-shaped, with the first end and the second end portion located at opposite ends along the length of the flexible conductive element.

25. The horizontal electroplating apparatus for battery cells according to claim 22, characterized in that: The flexible conductive element has a conductor layer along its thickness direction and a conductive adhesive layer disposed on one side of the conductor layer, the conductive adhesive layer being bonded to the bottom of the mask opening.

26. The horizontal electroplating apparatus for battery cells according to claim 25, characterized in that: The flexible conductive element also has a first coating layer disposed on the other side of the conductor layer, wherein the first coating layer is an insulating film layer or a hydrophobic film layer.

27. The horizontal electroplating apparatus for battery cells according to claim 26, characterized in that: The flexible conductive element also has a second coating layer disposed on the outside of the conductive adhesive layer, the second coating layer being an insulating film layer or a hydrophobic film layer, and the conductive adhesive layer being exposed at least at the first end.

28. The horizontal electroplating apparatus for battery cells according to claim 22, characterized in that: The electroplating apparatus further includes a conductive connector located outside the electroplating tank. The negative terminal of the external power supply is electrically connected to the conductive connector. The second end of the flexible conductive member is fixedly connected to the conductive connector and forms an electrical connection with the conductive connector.

29. The horizontal electroplating apparatus for battery cells according to claim 28, characterized in that: The conductive connector is an attachment frame, and the second end is fixedly attached to the attachment frame; or, the conductive connector is a gripper, and the second end is fixedly held by the gripper.

30. The horizontal electroplating apparatus for battery cells according to claim 28, characterized in that: The electroplating apparatus further includes a transmission mechanism capable of synchronously transmitting the battery cell and the conductive connector. The transmission mechanism includes a transmission track and a roller mechanism for transmitting the battery cell. The conductive connector is fixedly disposed on the transmission track.

31. The horizontal electroplating apparatus for battery cells according to claim 22, characterized in that: The electroplating tank is provided with an overflow port, and the electroplating device also includes an electroplating solution spraying system, which includes at least a spray pipe for conveying electroplating solution to the electroplating tank.

32. The horizontal electroplating apparatus for battery cells according to claim 22, characterized in that: The electroplating apparatus further includes a circulation mechanism disposed on the electroplating tank for circulating the electroplating solution in the electroplating tank. The circulation mechanism includes a second circulation component for circulating the electroplating solution in the lower part of the electroplating tank to the upper part of the electroplating tank, and / or a third circulation component for circulating the electroplating solution in the upper part of the electroplating tank to the lower part of the electroplating tank, and / or a first circulation component for circulating the electroplating solution in the lower part of the electroplating tank.

33. The horizontal electroplating apparatus for battery cells according to claim 22, characterized in that: The electroplating tank includes an electroplating reaction tank and a circulating replenishment tank stacked on top of each other, and the electroplating reaction tank is configured to overflow into the circulating replenishment tank in one direction.

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