Connection device for a composite collector and a foil material

Abstract

The present invention discloses a connection device and a connection method for a composite current collector and a foil material. The connection device includes a foil material unwinding roller, a composite current collector unwinding roller, a coating component, a double-fold component, a material pressing component, and a material winding component. The double-fold component, the material pressing component, and the material winding component are provided in this order. The coating component includes a slurry inlet pipe, a slurry return pipe, a slurry box, and a gravure roller. Both the slurry inlet pipe and the slurry return pipe are connected to the slurry box. The gravure roller is provided at the slurry outlet of the slurry box. The foil material on the foil material unwinding roller sequentially passes through the coating component and the double-fold component. The composite current collector on the composite current collector unwinding roller enters the double-fold component. The double-fold component is used to perform double folding on the foil material and the composite current collector and introduce them into the material pressing component for drying and rolling. The above-mentioned connection device for the composite current collector and the foil material can enhance the current passing ability from the battery core to the electrode terminal, solve the problem that current cannot pass through the polymer layer, reduce resistance, increase adhesion, enhance the mechanical strength of the material, and improve the use safety of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a connecting device for a composite current collector and a foil material and a connecting method thereof.

Background Art

[0002] Batteries are widely applied in the fields of consumer electronics products and electric vehicles due to advantages such as high energy density, long service life, being green and pollution-free, and high safety performance. How to achieve high safety and high energy density of batteries has already become the focus of current research. With the continuous development of the battery industry, a current collector with better performance appears, that is, a composite current collector formed by compounding a polymer and a metal. Regarding the advantages of the composite current collector, the first is to greatly improve safety, the second is to effectively increase the energy density of the battery, and the third is to reduce the thickness of the copper foil and reduce the raw material cost. Regarding the disadvantages of the composite current collector, since the composite current collector is provided with an insulating layer made of a polymer material, it is difficult to transport the current in the battery core to the electrode terminal.

[0003] Conventional technical solutions perform relay welding using a laser or ultrasonic waves (such as welding tooth welding or seam welding), weld the foil material and the composite current collector together, fuse the metal foil material and the metal layer on the side of the composite current collector at a high temperature during the welding process, and realize welding after cooling to enhance the current passing ability of the composite current collector. When using a laser or ultrasonic waves, the heat quantity is too high locally at the welding position (the laser is a high-energy light beam, and the ultrasonic waves convert high-frequency vibration energy into heat energy by friction to melt the contact surface of the metal foil material and the current collector into one), and since the center of the composite current collector is a polymer material, it will deform when receiving heat, and the polymer material will expand and come out during welding. When the polymer material expands and comes out due to heat, adhesion occurs, the welding teeth themselves adhere to the material, the processing accuracy decreases, the life of the ultrasonic welding teeth is affected, the mechanical strength of the material decreases, whether it is welding tooth welding or seam welding, since the polymer layer is penetrated during the welding process, the tensile strength of the composite current collector decreases, the folding resistance ability deteriorates, and it brings a safety risk to the battery.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Based on this, in view of the problems existing in the prior art of relay welding by laser or ultrasonic waves, such as the decrease in processing accuracy, the influence on the life of the ultrasonic welding teeth, the decrease in the mechanical strength of the material, the decrease in the tensile strength of the composite current collector, and the safety risk brought to the battery, the present invention provides a connecting device for the composite current collector and the foil material. The connecting device for the composite current collector and the foil material of the present invention can enhance the current passing ability from the battery core to the electrode terminal, solve the problem that the current cannot pass through the polymer layer, reduce the resistance, increase the adhesive force, enhance the mechanical strength of the material, and enhance the use safety of the battery.

Means for Solving the Problems

[0005] One embodiment includes a foil material unwinding roller, a composite current collector unwinding roller, a coating component, a double-fold component, a material pressing component, and a material winding component. The double-fold component, the material pressing component, and the material winding component are provided in this order. The coating component includes a slurry inlet pipe, a slurry return pipe, a slurry box, and a gravure roller. Both the slurry inlet pipe and the slurry return pipe are connected to the slurry box. The gravure roller is provided at the slurry outlet of the slurry box. The foil material on the foil material unwinding roller sequentially passes through the coating component and the double-fold component. The composite current collector on the composite current collector unwinding roller enters the double-fold component. The double-fold component is used to double-fold the foil material and the composite current collector and introduce them into the material pressing component to perform dry rolling, providing a connecting device for the composite current collector and the foil material.

[0006] In some of these embodiments, the coating component is provided at the slurry outlet of the slurry box and is located below the gravure roller. The coating component further includes a first approaching roller and a second approaching roller that cooperate with the gravure roller to perform gravure coating.

[0007] In some of these embodiments, the connecting device for the composite current collector and the foil material includes a pass roller, a swing roller provided at a distance from the pass roller, a swing roller holder to which the swing roller is movably connected, and a potential sensor attached to the swing roller holder and used to detect the angular position of the swing roller. The connecting device further includes a tension adjusting component provided between the foil material unwinding roller and the coating component, and / or between the composite current collector unwinding roller and the double-fold component, and / or between the material pressing component and the material winding component.

[0008] In some of these embodiments, the double-folded part includes a double-folded guide rail having a guide passage whose dimension gradually narrows along the advancing direction of the material, and a preliminary pressing roller and a preliminary folding roller both provided at the material inlet end of the double-folded guide rail. The preliminary pressing roller is used to preliminarily press the composite current collector, and the preliminary folding roller has an angle setting range of 20° to 60° and is used to preliminarily fold back the foil material advancing horizontally.

[0009] In some of these embodiments, the material pressing part further includes a first pressing roller and a second pressing roller which are oppositely provided and have an adjustable material pressing interval formed therebetween.

[0010] In some of these embodiments, the material pressing part further includes an exhaust hood covering the first pressing roller and the second pressing roller.

[0011] In some of these embodiments, the material winding part includes a winding roller and a pressing roller which are oppositely provided and have a material winding interval formed therebetween.

[0012] Another object of the present invention is to provide a method for connecting a composite current collector and a foil material.

[0013] The method for connecting a composite current collector and a foil material includes an adhesive liquid preparation step of preparing an adhesive liquid whose components include a solvent, a dispersant, a main material, a thickener, an adhesive and a wetting agent, and whose solid content ranges from 40% to 80% and viscosity ranges from 50 to 400 mPa·s; an application step of applying the adhesive liquid to the surface of the foil material; a foil material double-folding step of double-folding a flat foil material and bonding the two double-folded surfaces to the two surfaces of the composite current collector respectively; a rolling and drying step of performing a rolling and drying treatment on the bonded foil material and composite current collector; a winding step.

[0014] In some of these embodiments, the solvent in the adhesive liquid is an aqueous solvent, and / or, the dispersant contains one or two of ammonium salt-based compounds and polyphosphates, and the mass percentage in the adhesive liquid is 0.1 - 1%, and / or, the main material is one or more of silver powder, copper powder, gold powder, and aluminum powder, the particle size range is 0.1 - 10 μm, and the mass percentage in the adhesive liquid is 40 - 80%, and / or, the thickener has a viscosity range between 50 - 800 mPa·s, and the mass percentage in the adhesive liquid is 5 - 15%, and / or, the adhesive contains one or more of acrylic adhesives, styrene-butadiene latex, PVA, phenylacrylic acid, polyacrylamide, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, modified paraffin resin, carbomer resin, polyacrylic acid-based, polyurethane acrylate, polyacrylate copolymer emulsion, polyurethane, and carbamate, and the mass percentage in the adhesive liquid is 5 - 20%, and / or, the wetting agent contains one or more of organosilicon ether-based surfactants, anionic surfactants, and non-ionic surfactants, and the mass percentage in the adhesive liquid is 0.1 - 1%.

[0015] In some of these embodiments, when applying the adhesive liquid to the surface of the foil material, the coating methods include gravure coating, slit extrusion, spray coating, dip coating, electrospinning, or comma coating.

[0016] In some of these embodiments, when folding the foil material in half, a step of pre-folding the horizontally advancing foil material by a pre-folding roller, a step of bringing the foil material and the composite current collector closer by a pre-pressing roller, A step of folding the foil material and the composite current collector that are running on the double-fold guide rail in half, and bonding the two double-folded surfaces of the foil material to the two surfaces of the composite current collector respectively.

[0017] In some of these embodiments, the foil material and the composite current collector are passed through the material pressing interval between the first pressing roller and the second pressing roller for rolling and drying treatment, and the temperature range of the first pressing roller and the second pressing roller is 30°C to 80°C.

Advantages of the Invention

[0018] The connection device between the above-mentioned composite current collector and the foil material has the following beneficial effects compared with the prior art.

[0019] (1) The coating component provides a new connection method between the fresh metal foil material and the composite current collector, that is, the bonding method, which improves the current passing ability from the battery core to the electrode terminal and solves the problem that the current cannot pass through the polymer layer.

[0020] (2) By folding the foil material and the composite current collector that are running on the double-fold guide rail in half, and bonding the two double-folded surfaces of the foil material to the two surfaces of the composite current collector respectively, and simultaneously bonding the foil material to each of the two surfaces of the composite current collector, the contact area between the metal foil material and the current collector is increased, the resistance is reduced, and the bonding force is increased, and this bonding force is at least twice the force of bonding on one side.

[0021] (3) Before bonding the two surfaces of the foil material and the composite current collector, the foil material is pre-folded, the angle setting range of the pre-folding roller is 20° to 60°, and the horizontally advancing foil material is pre-folded back to achieve pre-folding. Next, the foil material is fed into the double-fold component. Since the dimensions of the double-fold guide rail gradually become narrower, the two surfaces of the foil material are gradually brought closer to the composite current collector, and the bonding effect is good.

[0022] (4) After the foil material coated with the coating liquid and the composite current collector are bonded together by a double-folded part, the foil material and the composite current collector pass through the material pressing interval between the first pressing roller and the second pressing roller and are subjected to rolling and drying treatment. The first pressing roller and the second pressing roller are heated to a temperature range of 30°C to 80°C for drying. The drying temperature is adjustable, the pressure between the first pressing roller and the second pressing roller is adjustable as required, and the drying effect is good.

[0023] (5) In the present invention, a gravure roller is adopted to apply the adhesive liquid. There are cells on the surface of the gravure roller by laser engraving. The amount of ink carried is determined by the depth and width of the cells, and the application amount of the adhesive liquid can be accurately controlled.

[0024] (6) In the connection method between the composite current collector and the foil material, a highly conductive adhesive liquid such as an adhesive liquid prepared from a conductive agent, carbon black, carbon nanotubes, conductive metal, etc. is adopted. As specific main materials, one or more of silver powder, copper powder, gold powder, and aluminum powder are used. A thickener, an adhesive, a wetting agent, etc. are added to the adhesive liquid. Since the main material has strong conductivity, the current passing ability between the foil material and the composite current collector can be enhanced. The adhesive provides an adhesive force between the metal foil material and the current collector. At the same time, the use of the thickener can prevent the precipitation of the main material, supplement the adhesive effect, avoid high-temperature welding, and does not cause mechanical damage to the material.

Brief Description of the Drawings

[0025] To more clearly explain the technical solutions in the embodiments of the present application, the drawings required for use in the following description of the embodiments will be briefly introduced below. The drawings described below are only some embodiments of the present application. It is obvious that those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0026] To more fully understand the present application and its beneficial effects, the following will be described with reference to the drawings. Among them, in the following description, the same parts are denoted by the same reference numerals.

[0027]

Figure 1

Explanation of reference numerals

[0028] 10 ··· Connecting device between a composite current collector and a foil material, 100 ··· Foil material unwinding roller, 200 ··· Composite current collector unwinding roller, 300 ··· Coating component, 301 ··· Slurry inlet pipe, 301 ··· Slurry return pipe, 303 ··· Slurry box, 304 ··· Gravure roller, 305 ··· First approaching roller, 306 ··· Second approaching roller, 400 ··· Double-fold component, 401 ··· Double-fold guide rail, 402 ··· Preliminary pressing roller, 403 ··· Preliminary folding roller, 500 ··· Material pressing component, 501 ··· First pressing roller, 502 ··· Second pressing roller, 503 ··· Exhaust hood, 600 ··· Material winding component, 601 ··· Winding roller, 602 ··· Material winding pressing roller, 700 ··· Tension adjusting component, 701 ··· Pass roller, 702 ··· Oscillating roller, 703 ··· Oscillating roller holder, 21 ··· Foil material, 22 ··· Composite current collector.

Mode for carrying out the invention

[0029] In order to make the above objects, features and advantages of the present invention clearer and more easily understandable, the specific embodiments of the present invention will be described in detail below with reference to the drawings. In the following description, many specific details are described so as to fully understand the present invention. However, the present invention can be implemented in many other forms different from those described here, and those skilled in the art can make similar improvements without violating the spirit of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0030] In the description of the present invention, terms such as "center", "longitudinal direction", "lateral direction", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial direction", "radial direction", "circumferential direction", etc. indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are merely for facilitating the description of the present invention and simplifying the description, and do not indicate or imply that the mentioned device or element must have a specific orientation and be configured and operated in a specific orientation. Therefore, it should not be understood as limiting the present invention.

[0031] Also, terms such as "first" and "second" are merely for the purpose of description, and should not be understood as indicating or implying relative importance or implicitly indicating the quantity of the technical features indicated. Thus, the features limited by "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, unless otherwise clearly and specifically limited, the meaning of "a plurality" is at least two, for example, two, three, etc.

[0032] In the present invention, unless otherwise clearly defined and limited, terms such as "attach", "connect", "join", "fix", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral one, a mechanical connection, an electrical connection, a direct connection, or an indirect connection through an intermediate medium, or a relationship of internal communication between two elements or an interaction between two elements. Unless otherwise clearly limited, those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific situation.

[0033] In the present invention, unless otherwise clearly defined and limited, for the first feature to be "above" or "below" the second feature, the first feature and the second feature may be in direct contact, or the first feature and the second feature may be in indirect contact through an intermediate medium. Further, for the first feature to be "above", "upper" and "upper surface" of the second feature, the first feature may be directly above or obliquely above the second feature, or simply indicate that the horizontal height of the first feature is higher than that of the second feature. For the first feature to be "below", "lower" and "lower surface" of the second feature, the first feature may be directly below or obliquely below the second feature, or simply indicate that the horizontal height of the first feature is lower than that of the second feature.

[0034] In addition, when an element is said to be "fixed to" or "provided on" another element, it may be directly on the other element, or there may be intervening elements. When an element is recognized as being "connected to" another element, it may be directly connected to the other element, or intervening elements may also be present at the same time. The terms "vertical", "horizontal", "above", "below", "left", "right" and similar descriptions used in this document are for illustrative purposes only and do not represent the only embodiment.

[0035] In the description of the present invention, some meanings are one or more, multiple meanings are two or more, and terms such as "greater than", "less than", "exceeding" are understood not to include the number, while "above", "below", "within" etc. are understood to include the number. If there are the first and second descriptions, the first and second are only for distinguishing technical features and cannot be understood as indicating or implying relative importance, or implicitly indicating the quantity or sequence relationship of the indicated technical features.

[0036] Unless otherwise defined, all technical and scientific terms used in this article have the same meaning as commonly understood by those skilled in the art. The terms used in the specification of the present invention in this article are merely for the purpose of explaining specific embodiments and are not intended to limit the present invention. The term "and / or" used in this article includes any and all combinations of one or more of the associated listed items.

[0037] The embodiments of the present application provide a connecting device 10 between a composite current collector and a foil material to solve the problems existing in relay welding by laser or ultrasonic wave in the prior art, such as reduced processing accuracy, affecting the service life of ultrasonic welding teeth, reduced mechanical strength of materials, reduced tensile strength of the composite current collector 22, and bringing safety risks to the battery. The following will be described with reference to the drawings.

[0038] Regarding the connecting device 10 between the composite current collector and the foil material according to the embodiments of the present application, for example, refer to the one shown in FIG. 1. FIG. 1 is a structural schematic diagram of the connecting device 10 between the composite current collector and the foil material according to the embodiments of the present application. The connecting device 10 between the composite current collector and the foil material of the present application can be used for the application of manufacturing batteries in fields such as consumer electronics products and electric vehicles.

[0039] To more clearly explain the structure of the connecting device 10 between the composite current collector and the foil material, the connecting device 10 between the composite current collector and the foil material will be introduced below with reference to the drawings.

[0040] For example, referring to the one shown in FIG. 1, the connecting device 10 between the composite current collector and the foil material includes a foil material unwinding roller 100, a composite current collector unwinding roller 200, a coating component 300, a double-fold component 400, a material pressing component 500, and a material winding component 600.

[0041] The double-fold component 400, the material pressing component 500, and the material winding component 600 are provided in this order.

[0042] The coating component 300 includes a slurry inlet pipe 301, a slurry return pipe 301, a slurry box 303, and a gravure roller 304. Both the slurry inlet pipe 301 and the slurry return pipe 301 are connected to the slurry box 303. The gravure roller 304 is provided at the slurry outlet of the slurry box 303, and among them, the slurry outlet is provided below the slurry box 303. The slurry inlet pipe 301 and the slurry return pipe 301 are provided at the top of the slurry box 303. The foil material 21 on the foil material unwinding roller 100 sequentially passes through the coating component 300 and the double-fold component 400.

[0043] The composite current collector unwinding roller 200 in the composite current collector 22 enters the double-fold component 400.

[0044] The double-fold component 400 is used to perform double folding on the foil material 21 and the composite current collector 22 and introduce them into the material pressing component 500 for dry rolling.

[0045] The material pressing component 500 and the material winding component 60 are each electrically connected to the PLC control system.

[0046] In some of these embodiments, the gravure roller 304 is an anilox roller. In one specific embodiment, the specifications are 130 LPI and a groove depth of 90 μm. It is not difficult to understand that in other embodiments, the specifications of the gravure roller 304 are 150 LPI and a groove depth of 100 μm. The specifications of the gravure roller 304 can be set as required.

[0047] In some of these embodiments, the coating component 300 further includes a first approaching roller 305 and a second approaching roller 306. The first approaching roller 305 and the second approaching roller 306 are provided at the slurry outlet of the slurry box 303 and are both located below the gravure roller 304. The first approaching roller 305 and the second approaching roller 306 cooperate with the gravure roller 304 to perform gravure coating. The first approaching roller 305 and the second approaching roller 306 are provided in the same horizontal direction so that the foil material 21 advances in the horizontal direction.

[0048] In some of these embodiments, the connection device 10 between the composite current collector and the foil material further includes a tension adjusting component 700. The tension adjusting component 700 includes a pass roller 701, a swing roller 702, a swing roller holder 703, and a potential sensor. The swing roller 702 is movably connected to the swing roller holder 703. The potential sensor is attached to the swing roller holder 703 and is used to detect the angular position of the swing roller 702. The pass roller 701 and the swing roller 702 are provided at an interval. A tension adjusting component 700 is provided between the foil material unwinding roller 100 and the coating component 300, and / or between the composite current collector unwinding roller 200 and the double-folding component 400, and / or between the material pressing component 500 and the material winding component 600. The potential sensor is electrically connected to the PLC control system.

[0049] Preferably, a tension adjusting component 700 is provided between the foil material unwinding roller 100 and the coating component 300, between the composite current collector unwinding roller 200 and the double-folding component 400, and between the material pressing component 500 and the material winding component 600. The potential sensor can convert a voltage signal into an angular signal to determine the position of the swing roller 702. During the normal operation process, the swing roller 702 should be in the middle position. When the swing roller 702 deviates from the middle position, the potential sensor transmits a signal to the PLC control system for processing, and the PLC control system transmits a signal to the servo motor based on the signal to make it operate, so that the tension control is stable and accurate.

[0050] In some of these embodiments, the double-folded part 400 includes a double-folded guide rail 401, a preliminary pressing roller 402, and a preliminary folding roller 403. The preliminary pressing roller 402 and the preliminary folding roller 403 are both provided at the material inlet end of the double-folded guide rail 401. The double-folded guide rail 401 has a guide passage. The dimensions of the guide passage gradually narrow along the advancing direction of the material. The preliminary pressing roller 402 is used to preliminarily press the composite current collector 22. The preliminary folding roller 403 has an angle setting range of 20° to 60° and is used to preliminarily fold back the foil material 21 that is advancing horizontally.

[0051] In some of these embodiments, the material pressing component 500 further includes a first pressing roller 501 and a second pressing roller 502. The first pressing roller 501 and the second pressing roller 502 are provided opposite to each other, and a material pressing interval is formed therebetween. The material pressing interval between the first pressing roller 501 and the second pressing roller 502 is adjustable. Both the first pressing roller 501 and the second pressing roller 502 are heated pressing rollers, and they are heated to a temperature of 30°C to 80°C for drying, and the drying temperature is adjustable. The pressure between the first pressing roller 501 and the second pressing roller 502 is adjustable as required. By applying pressure to the first pressing roller 501 and the second pressing roller 502, the adhesion can be made stronger and flatter.

[0052] In some of these embodiments, each of the first pressing roller 501 and the second pressing roller 502 is driven to rotate by a driving member, and the driving member can also apply pressure to each of the first pressing roller 501 and the second pressing roller 502. The driving member is not shown in FIG. 1. The driving member is electrically connected to the PLC control system.

[0053] In some of these embodiments, the material pressing component 500 further includes an exhaust hood 503. The exhaust hood 503 is provided to cover the first pressing roller 501 and the second pressing roller 502.

[0054] In some of these embodiments, the material winding component 600 includes a winding roller 601 and a material winding pressing roller 602. The winding roller 601 and the material winding pressing roller 602 are provided opposite to each other, and a material winding interval is formed therebetween. By driving the winding roller 601 to rotate, the material winding pressing roller 602 cooperates with the winding roller 601 to realize the winding of the finished product. Below the winding roller 601, a material winding pressing roller 602 is provided. The material winding pressing roller 602 is used to discharge the air between the materials during winding, reduce the air content, and make the winding flatter.

[0055] In some of these embodiments, the material winding component 600 further includes a material winding driving component. The material winding driving component is connected to the winding roller 601 and is used to drive the winding roller 601 to rotate. The material winding driving component is electrically connected to a PLC control system.

[0056] Another object of the present invention is to provide a method for connecting a composite current collector and a foil material.

[0057] The method for connecting a composite current collector and a foil material includes an adhesive liquid preparation step of preparing an adhesive liquid whose components include a solvent, a dispersant, a main material, a thickener, an adhesive, and a wetting agent, the solid content range is 40 - 80%, and the viscosity range is 50 - 400 mPa·s, by putting the above components in this order, and stirring at a certain rotation speed for a certain time each time a component is put in, and finally forming an adhesive liquid; a coating step of coating the adhesive liquid on the surface of the foil material 21; a two - fold step of folding the flat foil material 21 in half and bonding the two folded surfaces to the two surfaces of the composite current collector 22 respectively; a rolling and drying step of performing a rolling and drying treatment on the bonded foil material 21 and composite current collector 22; and a winding step.

[0058] In some of these embodiments, the overall running speed range of the composite current collector 22 and the foil material 21 is 10 to 100 m / min. For example, in one specific embodiment among them, the overall running speed of the composite current collector 22 and the foil material 21, that is, the coating speed, is 30 m / min.

[0059] In some of these embodiments, the application amount range of the adhesive liquid is 0.1 to 1.5 g / m 2 For example, in one specific embodiment among them, the application amount is 1.0 g / m 2

[0060] In some of these embodiments, the solvent in the adhesive liquid is an aqueous solvent. The adhesive liquid contains water, alcohol, etc., and the aqueous solvent is pollution-free and environmentally friendly. The input amount of the solvent in the adhesive liquid is determined according to the target solid content. The higher the solid content, the less the required amount of the solvent.

[0061] In some of these embodiments, the dispersant contains one or two of ammonium salt-based compounds and polyphosphates. For the dispersant, one or more of sodium pyrophosphate, sodium tripolyphosphate, sodium hexametaphosphate, alkylaryl phosphate, alkylbenzene sulfonate, dialkyl sulfosuccinate, polycarboxylate, poly(meth)acrylic acid derivative, and maleic anhydride copolymer are selected. The mass percentage of the dispersant in the adhesive liquid is 0.1 to 1%, and its function is to reduce the surface energy of the solvent, reduce the aggregation of the main material, and uniformly disperse the main material in the solvent.

[0062] In some of these embodiments, the main material is one or more of silver powder, copper powder, gold powder, and aluminum powder. Since the conductivity ranking of metals is silver > copper > gold > aluminum, the main material is preferably silver powder. The silver powder can increase the conductivity at the connection point of the interface between the foil material 21 and the current collector. The particle size range of the main material, such as silver powder, is 0.1 to 10 μm, and the mass percentage of the main material in the adhesive liquid is 40 to 80%. ​

[0063] In some of these embodiments, the thickener has a viscosity range between 50 and 800 mPa·s and a mass percentage in the adhesive liquid of 5% to 15%. Regarding the three functions of the thickener, the first is that it can adjust the viscosity of the silver paste. If the viscosity is too low during the coating process, the adhesive liquid will drop, which is disadvantageous for the retention of the adhesive liquid on the foil material 21. The second is that it can prevent precipitation. The thickener generally has a network three-dimensional structure, fixes the main material, and plays a role in dust prevention. Commonly used ones include sodium carboxymethyl cellulose, etc. The third is that it plays an adhesive assisting role and enhances the adhesiveness when used in combination with the following adhesives.

[0064] In some of these embodiments, the adhesive includes one or more of acrylic adhesives, styrene-butadiene latex, PVA, phenylacrylic acid, polyacrylamide, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, modified paraffin resin, carbomer resin, polyacrylic acid-based, polyurethane acrylate, polyacrylate copolymer emulsion, polyurethane, and carbamate, and has a mass percentage in the adhesive liquid of 5% to 20%. Its function is to adhere the surface of the foil material 21 and the current collector.

[0065] In some of these embodiments, the wetting agent includes one or more of organosilicon ether-based surfactants, anionic surfactants, and non-ionic surfactants, and has a mass percentage in the adhesive liquid of 0.1% to 1%. The anionic surfactant is sodium alkylaryl sulfonate, sodium butylnaphthalene sulfonate, sodium hydroxyethyl sulfonate, or sodium dodecyl sulfonate. The non-ionic surfactant is long-chain aliphatic alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, polyoxyethylene alkanolamide, or aliphatic alcohol polyoxyethylene ether. The main purpose of the wetting agent is to lower the surface tension of the silver paste, increase the leveling property, and make it easier to apply the silver paste on the surface of the foil material 21.

[0066] For example, in one specific example, the preparation of the adhesive liquid includes the following steps.

[0067] The components of the adhesive liquid include a solvent, a dispersant, a main material, a thickener, an adhesive, a wetting agent, and the like.

[0068] In S11, water is selected as the solvent, and 26.2 Kg of water is charged into a double planetary stirring tank.

[0069] In S12, 0.3 Kg of an ammonium salt-based dispersant is weighed as the dispersant and charged into a double planetary mixer and stirred. The rotation speed of the stirring is 500 rpm, and the time is 10 min.

[0070] In S13, silver powder with a particle size of D50 of 1 μm is selected as the main material, 55 Kg of silver powder is weighed and charged into a double planetary mixer and stirred. The rotation speed of the stirring is 1000 rpm, and the time is 60 min.

[0071] In S14, sodium carboxymethyl cellulose is selected as the thickener, 8 Kg of CMC is weighed and charged into a double planetary mixer and stirred. The rotation speed of the stirring is 500 rpm, and the time is 30 min.

[0072] In S15, an acrylic acid-based adhesive is selected as the adhesive, 10 Kg of the adhesive is weighed and charged into a double planetary mixer and stirred. The rotation speed of the stirring is 500 rpm, and the time is 30 min.

[0073] In S16, an organosilicon ether-based surfactant is selected as the wetting agent, 0.5 Kg is weighed and charged into a double planetary mixer and stirred. The rotation speed of the stirring is 300 rpm, and the time is 20 min.

[0074] In S17, the above components are charged in this order to finally form an adhesive liquid with a solid content of 55% and a viscosity of 230 mPa·s.

[0075] In some of these embodiments, when applying the adhesive liquid to the surface of the foil material 21, the application methods include gravure coating, slit extrusion, spray coating, dip coating, electrospinning or comma coating. Preferably, according to the characteristics of the slurry, in one of the embodiments, gravure coating and slit extrusion are adopted in the application. As shown in FIG. 1, when gravure coating is used, specifically, the foil material 21 is first unwound from the unwinding shaft, gradually run below the coating head, the coating head is pressed against the foil material 21 downward, and the silver paste on the gravure roller 304 is transferred to the surface of the foil material 21. Below the foil material 21, a first approaching roller 305 and a second approaching roller 306 are attached. Regarding the two functions of the first approaching roller 305 and the second approaching roller 306, the first is to provide support for the upper foil material 21 and flatten the foil surface when it is being coated. The second is that the first approaching roller 305 and the second approaching roller 306 are adjustable up and down. Thereby, by adjusting the holding angle between the foil material 21 and the gravure roller 304, some defects in the coating process, such as streaks and coating leakage, etc. are solved.

[0076] In some of these embodiments, when folding the foil material 21 in half, the following steps are included.

[0077] The preliminary folding roller 403 preliminarily folds the horizontally advancing foil material 21. Behind the coating component 300 and in front of the double-folding component 400, a single preliminary folding roller 403 with a certain angle is provided. The function of the preliminary folding roller 403 is to preliminarily fold the horizontally advancing foil material 21, and the angle setting range is between 20° and 60°.

[0078] The preliminary pressing roller 402 brings the foil material 21 and the composite current collector 22 closer. Specifically, at a location immediately before entering the double-folding component 400, one preliminary pressing roller 402 for bringing the foil material 21 and the composite current collector 22 closer is attached. Further, a misalignment corrector for alignment may be attached in preparation for entering the double-folding component 400.

[0079] The foil material 21 and the composite current collector 22 running on the double-fold guide rail 401 are double-folded, and the two double-folded surfaces of the foil material 21 are respectively bonded to the two surfaces of the composite current collector 22. The opening of the double-fold guide rail 401 gradually becomes narrower, gradually double-folding the running foil material 21 and the composite current collector 22. When the material is sent out from the double-fold guide rail 401, the foil material 21 and the composite current collector 22 are almost bonded together and double-folded.

[0080] In some of these embodiments, the foil material 21 and the composite current collector 22 pass through the material pressing interval between the first pressing roller 501 and the second pressing roller 502 for rolling and drying treatment. The temperature range of the first pressing roller 501 and the second pressing roller 502 is 30°C to 80°C. When the material passes through the roller pair, solvents such as moisture in the silver paste receive heat and volatilize, and the solvent after receiving heat and volatilizing can be collected by the exhaust hood 503. Thereby, the volatilized water vapor is discharged in a timely manner, preventing the humidity from being too high and causing condensation, and the adhesive from solidifying and adhering. The material pressing interval between the first pressing roller 501 and the second pressing roller 502 is adjustable. By drying and applying a certain pressure to the material, the adhesion is made stronger and flatter.

[0081] The connection device 10 between the above-mentioned composite current collector and the foil material has the following beneficial effects compared with the prior art.

[0082] (1) The coating component 300 provides a new connection method, that is, an adhesion method, between the fresh metal foil material 21 and the composite current collector 22, improving the current passing ability from the battery core to the electrode terminal and solving the problem that current cannot pass through the polymer layer.

[0083] (2) The foil material 21 and the composite current collector 22 running on the double-fold guide rail 401 are double-folded, and the two double-folded surfaces of the foil material 21 are respectively bonded to the two surfaces of the composite current collector 22, and the foil material 21 is simultaneously adhered to each of the two sides of the composite current collector 22, so as to increase the contact area between the metal foil material 21 and the current collector, reduce the resistance, and increase the adhesive force, and this adhesive force is at least twice that of the force of bonding on one side.

[0084] (3) Before bonding the two sides of the foil material 21 and the composite current collector 22, the foil material 21 is pre-folded, the angle setting range of the pre-fold roller 403 is set to 20° to 60°, and the horizontally advancing foil material 21 is pre-folded back to realize the pre-folding. Next, the foil material 21 is fed into the double-fold part 400. Since the dimensions of the double-fold guide rail 401 gradually become narrower, the two sides of the foil material 21 are gradually brought closer to the composite current collector 22, and the bonding effect is good.

[0085] (4) After the foil material 21 coated with the adhesive and the composite current collector 22 are bonded by the double-fold part 400, the foil material 21 and the composite current collector 22 pass through the material pressing interval between the first pressing roller 501 and the second pressing roller 502 and are subjected to rolling and drying treatment. The first pressing roller 501 and the second pressing roller 502 are heated to a temperature range of 30°C to 80°C for drying. The drying temperature is adjustable, the pressure between the first pressing roller 501 and the second pressing roller 502 is adjustable as required, and the drying effect is good.

[0086] (5) In the present invention, a gravure roller 304 is adopted to apply the adhesive. There are cells on the surface of the gravure roller 304 by laser engraving. The amount of ink carried is determined by the depth and width of the cells, and the application amount of the adhesive can be accurately controlled.

[0087] (6) In the method of connecting the composite current collector and the foil material, a highly conductive adhesive such as an adhesive solution prepared from a conductive agent, carbon black, carbon nanotubes, a conductive metal, etc. is adopted. As specific main materials, one or more of silver powder, copper powder, gold powder, and aluminum powder are used. Thickeners, adhesives, wetting agents, etc. are added to the adhesive solution. Since the main material has strong conductivity, the current passing ability between the foil material 21 and the composite current collector 22 can be enhanced. The adhesive provides an adhesive force between the metal foil material 21 and the current collector. At the same time, the use of the thickener can prevent the precipitation of the main material, supplement the adhesive effect, avoid high-temperature welding, and does not cause mechanical damage to the material.

[0088] In the above embodiments, each embodiment has its own focus. For parts not described in detail in a certain embodiment, the relevant descriptions of other embodiments can be referred to.

[0089] The technical features of the above-described embodiments can be arbitrarily combined. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as these technical feature combinations do not conflict, they should be regarded as within the scope described in this specification.

[0090] The above-described embodiments merely show some embodiments of the present invention, and their descriptions are specific and detailed, but they cannot be understood as limiting the scope of the present invention. Those skilled in the art should note that, on the premise of not departing from the concept of the present invention, several further modifications and improvements can be made, and all of these belong to the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the appended claims.

Claims

1. It is provided with a foil material unwinding roller, a composite current collector unwinding roller, a coating component, a double-fold component, a material pressing component, and a material winding component. The double-fold component, the material pressing component, and the material winding component are provided in this order. The coating component includes a slurry inlet pipe, a slurry return pipe, a slurry box, and a gravure roller. Both the slurry inlet pipe and the slurry return pipe are connected to the slurry box. The gravure roller is provided at the slurry outlet of the slurry box. The foil material on the foil material unwinding roller sequentially passes through the coating component and the double-fold component. The composite current collector on the composite current collector unwinding roller enters the double-fold component. The double-fold component is used to perform a double-fold on the foil material and the composite current collector and introduce them into the material pressing component for dry rolling. A connecting device for a composite current collector and a foil material, characterized by the above.

2. The coating component is provided at the slurry outlet of the slurry box and is both located below the gravure roller. It further includes a first approaching roller and a second approaching roller that perform gravure coating in cooperation with the gravure roller. The connecting device for a composite current collector and a foil material according to Claim 1, characterized by the above.

3. It is provided with a pass roller, a swing roller provided at an interval from the pass roller, a swing roller holder to which the swing roller is movably connected, and a potential sensor attached to the swing roller holder and used to detect the angular position of the swing roller. It further includes a tension adjusting component provided between the foil material unwinding roller and the coating component, and / or between the composite current collector unwinding roller and the double-fold component, and / or between the material pressing component and the material winding component. The connecting device for a composite current collector and a foil material according to Claim 1, characterized by the above.

4. The double-fold component includes a double-fold guide rail having a guide passage whose dimension gradually narrows along the material advancing direction, and a preliminary pressing roller and a preliminary folding roller both provided at the material receiving end of the double-fold guide rail. The preliminary pressing roller is used to preliminarily press the composite current collector. The preliminary folding roller has an angle setting range of 20° to 60° and is used to preliminarily fold back the horizontally advancing foil material. The connecting device for a composite current collector and a foil material according to any one of Claims 1 to 3, characterized by the above.

5. The material pressing component further includes a first pressing roller and a second pressing roller which are provided opposite to each other and have an adjustable material pressing interval formed therebetween. The connecting device for the composite current collector and the foil material according to any one of claims 1 to 3, characterized in that.

6. The material pressing component further includes an exhaust hood covering the first pressing roller and the second pressing roller. The connecting device for the composite current collector and the foil material according to claim 5, characterized in that.

7. The material winding component includes a winding roller and a pressing roller which are provided opposite to each other and have a material winding interval formed therebetween. The connecting device for the composite current collector and the foil material according to any one of claims 1 to 3 and 6, characterized in that.

8. An adhesive liquid preparation step of preparing an adhesive liquid whose components include a solvent, a dispersant, a main material, a thickener, an adhesive, and a wetting agent, with a solid content range of 40 to 80% and a viscosity range of 50 to 400 mpa.s; A coating step of coating the adhesive liquid on the surface of the foil material; A foil material folding step of folding a flat foil material in half and bonding the two folded surfaces to the two surfaces of the composite current collector respectively; A rolling and drying step of performing a rolling and drying treatment on the bonded foil material and composite current collector; A winding step, including; The connecting method for the composite current collector and the foil material, characterized in that.

9. The solvent in the adhesive liquid is an aqueous solvent, and / or the dispersant includes one or two of an ammonium salt-based compound and a polyphosphate, and the mass percentage in the adhesive liquid is 0.1 to 1%; and / or the main material is one or more of silver powder, copper powder, gold powder, and aluminum powder, with a particle size range of 0.1 to 10 μm and a mass percentage in the adhesive liquid of 40 to 80%; and / or the thickener has a viscosity range of 50 to 800 mpa.s and a mass percentage in the adhesive liquid of 5 to 15%; and / or the adhesive includes one or more of an acrylic acid-based adhesive, styrene-butadiene latex, PVA, phenylacrylic acid, polyacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide, modified paraffin resin, carbomer resin, polyacrylic acid-based, polyurethane acrylate, polyacrylate copolymer emulsion, polyurethane, and carbamate, and the mass percentage in the adhesive liquid is 5 to 20%. And / or, the wetting agent contains one or more of organosilicon ether surfactants, anionic surfactants, and nonionic surfactants, and the mass percentage in the adhesive liquid is 0.1 to 1%. The method for connecting a composite current collector and a foil material according to claim 8, characterized in that.

10. When applying the adhesive liquid to the surface of the foil material, the application methods include gravure coating, slit extrusion, spray coating, dip coating, electrospinning, or comma coating. The method for connecting a composite current collector and a foil material according to claim 8, characterized in that.

11. When folding the foil material in half, a step of pre-folding the foil material advancing horizontally by a pre-folding roller; a step of bringing the foil material and the composite current collector closer by a pre-pressing roller; a step of folding the foil material and the composite current collector running by a double-fold guide rail in half, and bonding the two folded surfaces of the foil material to the two surfaces of the composite current collector respectively. The method for connecting a composite current collector and a foil material according to claim 8, characterized in that.

12. The foil material and the composite current collector pass through the material pressing interval between the first pressing roller and the second pressing roller and are subjected to rolling and drying treatment, and the temperature range of the first pressing roller and the second pressing roller is 30°C to 80°C. The method for connecting a composite current collector and a foil material according to claim 8, characterized in that.

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