Current collector, pole piece and electrochemical device

Abstract

The utility model discloses a current collector, a pole piece and an electrochemical device, and belongs to the technical field of secondary batteries. The current collector comprises a base film and two conductive metal layers which are distributed in the thickness direction X, the base film is arranged between the two conductive metal layers, the base film comprises a polymer base film body and a metal belt which are distributed in the film surface direction Y, the film surface direction is perpendicular to the thickness direction, and the metal belt is arranged between the two conductive metal layers. The metal belt is arranged on at least one side of the polymer base film body; by arranging the metal belt on at least one side of the polymer base film body, conduction of the conductive metal layers on the upper face and the lower face of the base film is achieved, a traditional welding method can be applied to composite current collector tab welding, and the problems of missing welding, insufficient welding, weld penetration, high resistance, low bonding strength at the welding position and the like are effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of secondary batteries, in particular to a current collector, a pole piece and an electrochemical device. BACKGROUND

[0002] The composite current collector is a new type of current collector material composed of a polymer material and a metal, which is used to replace the traditional current collector and has the advantages of improving the safety performance of the battery, increasing the energy density and reducing the manufacturing cost. In a lithium battery, the tab and the current collector are connected by welding. However, using the traditional tab welding method, such as ultrasonic welding and melting welding, on the composite current collector can easily cause defects such as incomplete welding, false welding, burning through, high resistance and low bonding strength at the welding site. The current mainstream welding method for the composite current collector, i.e., adapter welding, also has problems such as high resistance, low bonding strength and burning through at the welding site. CONTENT OF THE UTILITY MODEL

[0003] The applicant believes that the reason for the welding defects in the quality inspection of the tab and the composite current collector may be that the polymer intermediate layer itself is not conductive and has a melting point much lower than that of the metal material.

[0004] The present application provides a current collector, a pole piece and an electrochemical device, which can reduce the occurrence of defects in the welding of the tab and the composite current collector.

[0005] In a first aspect, the present application provides a current collector, which includes a base film and two conductive metal layers distributed along a thickness direction X, the base film being arranged between the two conductive metal layers, the base film including a polymer base film body and a metal strip distributed along a film surface direction Y, the film surface direction being perpendicular to the thickness direction, and the metal strip being arranged on at least one side of the polymer base film body.

[0006] In the above implementation process, by arranging the metal strip on at least one side of the polymer base film body, the two conductive metal layers on the upper and lower surfaces of the base film are made conductive, so that the traditional welding method can be used for the welding of the tab and the composite current collector, effectively avoiding problems such as incomplete welding, false welding, burning through, high resistance and low bonding strength at the welding site.

[0007] As an optional implementation, the metal strip is provided with a first groove near an end face of the polymer base film body, and the polymer base film body is provided with a first protrusion near an end face of the metal strip, the first protrusion being matched with the first groove.

[0008] In the above implementation process, by arranging the first groove, the welding strength of the tab can be further improved, the peeling force of the tab can be effectively improved, and the resistance value of the pole piece can also be reduced.

[0009] As an optional implementation, the metal strip is provided with a plurality of the first grooves, and a ratio of a width of the first grooves to a pitch of the first grooves is 1-10 along the thickness direction X.

[0010] As an optional implementation, the width of the first grooves is 500-2000 nm; and / or

[0011] The depth of the first grooves is 200-2000 nm; and / or

[0012] The metal strip is provided with a plurality of the first grooves, and a pitch of the first grooves is 50-200 nm.

[0013] As an optional implementation, a coupling agent layer is arranged between the polymer-based film body and the metal strip.

[0014] In the above implementation process, by arranging the coupling agent layer between the polymer-based film body and the metal strip, the bonding force between the polymer-based film body and the metal strip can be increased, and thus the peeling force of the tab can be improved.

[0015] As an optional implementation, the thickness of the coupling agent layer is 5-100 nm.

[0016] As an optional implementation, the material of the coupling agent layer includes at least one of ethenyl triperoxy tert-butyl silane, butadienyl triethoxysilane, ethenyl triethoxysilane, ethenyl trimethoxysilane, ethenyl tri(β-methoxyethoxy)silane, ethenyl silane, amino silane or methacryloyloxy silane.

[0017] As an optional implementation, both surfaces of the base film are provided with second grooves, and the conductive metal layer arranged close to the side surface of the base film is provided with second protrusions matched with the second grooves.

[0018] In the above implementation process, by arranging the second grooves, the welding strength of the tab can be further improved, the peeling force of the tab can be effectively improved, and the resistance value of the tab can be reduced.

[0019] As an optional implementation, the width of the second grooves is 1-10 μm; and / or

[0020] The depth of the second grooves is 50-2000 nm; and / or

[0021] The pitch of the second grooves is 1-10 μm.

[0022] As an optional implementation, the conductive metal layer includes a conductive metal layer body and a bonding layer, and the bonding layer is arranged between the conductive metal layer body and the base film.

[0023] In the implementation process, the bonding layer is provided, the bonding layer has good bonding force with the conductive metal layer body and the base film, and thus the bonding force between the conductive metal layer body and the base film is increased.

[0024] As an optional implementation, the two surfaces of the base film are provided with second grooves, and the thickness of the bonding layer is greater than the depth of the second grooves.

[0025] In the implementation process, the thickness of the bonding layer is greater than the depth of the second grooves, so that the conductive metal layer body is combined with the bonding layer, and thus the bonding force between the entire conductive metal layer and the base film is increased.

[0026] As an optional implementation, the water content of the polymer base film body is less than or equal to 0.5%; and / or

[0027] The thermal shrinkage rate of the polymer base film body after being baked at 150℃ for 30min is less than or equal to 5%; and / or

[0028] The elongation at break of the polymer base film body is greater than or equal to 34%.

[0029] In the implementation process, the water content of the polymer base film body is controlled to be less than or equal to 0.5%, which can reduce the generation of impurities during the preparation of the conductive metal layer, and thus the adhesion between the conductive metal layer and the base film is improved. Meanwhile, the thermal shrinkage rate of the polymer base film body after being baked at 150℃ for 30min is controlled to be less than or equal to 5% and the elongation at break is greater than or equal to 34%, which can reduce the shrinkage of the base film body during the preparation of the conductive metal layer, improve the yield of the product, and reduce the stress between the polymer base film body and the conductive metal layer, thereby avoiding the peeling of the plating layer.

[0030] As an optional implementation, the thickness of the base film is 2-10μm; and / or

[0031] The width of the metal strip is 10-100mm; and / or

[0032] The thickness of the conductive metal layer is 500-1600nm.

[0033] As an optional implementation, the components of the polymer base film body include at least one of polyethylene terephthalate, polypropylene, polyethylene, polyimide, polyethylene naphthalate, polycarbonate, polyether ether ketone, cyclic polyolefin, polyarylate, polyether sulfone, polyether imide, and polyamide imide; and / or

[0034] The components of the metal strip include at least one of copper, aluminum, stainless steel, chromium, and nickel; and / or

[0035] The component of the bonding layer includes at least one of chromium, nickel, nickel-chromium alloy, copper oxide, aluminum oxide and chromium oxide; and / or

[0036] The component of the conductive metal layer body includes at least one of copper, aluminum, stainless steel, chromium and nickel.

[0037] In a second aspect, the embodiments of the present application provide a method for preparing a current collector, the method comprising:

[0038] Bonding the polymer-based film body and the metal-based strip to obtain a base film.

[0039] Preparation of a conductive metal layer on the base film to obtain a current collector.

[0040] As an optional implementation, the bonding of the polymer-based film body and the metal-based strip to obtain a base film comprises:

[0041] Obtaining a metal-based strip;

[0042] The polymer-based film body is prepared by injection molding, and the bonding of the polymer-based film body and the metal-based strip is completed at the same time of injection molding to obtain a base film.

[0043] As an optional implementation, the polymer-based film body is prepared by injection molding, and the bonding of the polymer-based film body and the metal-based strip is completed at the same time of injection molding to obtain a base film comprises:

[0044] At least one metal-based strip is arranged at the edge of the injection molding cavity, and injection molding is performed in the injection molding cavity to form a polymer-based film body and bond the polymer-based film body and the metal-based strip to obtain a base film.

[0045] As an optional implementation, before the preparation of the conductive metal layer, the method further comprises:

[0046] Shrinking heat treatment and rewinding of the base film in a vacuum environment to remove water vapor in the base film;

[0047] Shrinking heat treatment and rewinding of the base film after removal of water vapor in an inert atmosphere to avoid re-absorption of water vapor by the base film.

[0048] In the above implementation process, by successively performing shrinking heat treatment and rewinding of the base film in a vacuum environment and an inert atmosphere, the water vapor in the base film can be reduced, thereby reducing the generation of impurities during the preparation of the conductive metal layer, which is conducive to the adhesion of the conductive metal layer and the base film. At the same time, since shrinking heat treatment is performed, the shrinkage of the base film body during the preparation of the conductive metal layer can be reduced, the yield of the product is improved, and the stress between the polymer-based film body and the conductive metal layer can be reduced.

[0049] In a third aspect, an electrode sheet is provided. The electrode sheet includes the current collector provided in the first aspect.

[0050] As an optional implementation, the electrode sheet further includes a tab, and the tab is located corresponding to the metal strip.

[0051] In a fourth aspect, an electrochemical device is provided. The electrochemical device includes the electrode sheet provided in the third aspect. BRIEF DESCRIPTION OF DRAWINGS

[0052] The accompanying drawings, which are incorporated herein and constitute part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0053] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, for those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0054] Figure 1 A first structural schematic diagram of the current collector provided in the embodiments of the present application;

[0055] Figure 2 A second structural schematic diagram of the current collector provided in the embodiments of the present application;

[0056] Figure 3 A third structural schematic diagram of the current collector provided in the embodiments of the present application;

[0057] Figure 4 A flowchart of the method provided in the embodiments of the present application;

[0058] Figure 5 A structural schematic diagram of the current collector provided in the prior art.

[0059] Legend: 1000-current collector; 100-base film; 110-polymer base film body; 111-first protrusion; 120-metal strip; 121-first groove; 130-second groove; 200-conductive metal layer; 210-bonding layer; 220-conductive metal layer body; 230-second protrusion. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0061] Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or prepared by existing methods.

[0062] In lithium batteries, the tab and the current collector are connected by welding. However, using traditional tab welding methods such as ultrasonic welding, melting welding, etc. on composite current collectors is prone to cause defects such as missed welding, false welding, burning through, high resistance, low bonding strength at the welding site, etc. The current mainstream welding method for composite current collectors, adapter welding, also has problems such as high resistance at the welding site, low bonding strength, and welding through.

[0063] The applicant believes that the reason for the welding defects in the current tab and composite current collector quality inspection may be due to the fact that the polymer intermediate layer itself is not conductive and has a melting point much lower than that of metal materials.

[0064] Therefore, the present application intends to provide a current collector which is provided with a metal strip on at least one side of a polymer base film body to realize conduction of the conductive metal layers on the upper and lower surfaces of the base film, so that the traditional welding method can be used for tab welding on the composite current collector, effectively avoiding problems such as missed welding, false welding, burning through, high resistance, and low bonding strength at the welding site.

[0065] Figures 1 to 3 The structure schematic diagram of the current collector provided by the embodiments of the present application is shown in FIG. 1, and the embodiments of the present application provide a current collector, which includes a base film 100 and two conductive metal layers 200 distributed along a thickness direction X, the base film 100 is arranged between the two conductive metal layers 200, the base film 100 includes a polymer base film body 110 and a metal strip 120 distributed along a film surface direction Y, the film surface direction is perpendicular to the thickness direction, and the metal strip 120 is arranged on at least one side of the polymer base film body 110. Figures 1 to 3 The base film 100 arranged between the two conductive metal layers 200 means that the current collector 1000 as a whole has a sandwich structure, and the base film 100 is arranged in the middle.

[0066]

[0067] ​The number and position of the metal strips 120 are determined according to the number of the tabs of the actual required pole piece, for example, when the number of the tabs of the pole piece is 2, the number of the metal strips 120 is also 2. When the tabs of the pole piece are arranged on both sides, the positions of the metal strips 120 are also arranged on both sides of the polymer base film body 110.

[0068] The current collector 1000 realizes the conduction of the conductive metal layer 200 on the upper and lower surfaces of the base film 100 by arranging the metal strips 120 on at least one side of the polymer base film body 110, so that the traditional welding method can be applied to the tab welding of the composite current collector 1000, effectively avoiding the problems of missed welding, false welding, welding through, high resistance, low bonding strength at the welding position, etc.

[0069] In some embodiments, the thickness of the base film 100 can be 2-10 μm; the width of the metal strip 120 can be 10-100 mm; and the thickness of the conductive metal layer 200 can be 500-1600 nm. The composition of the polymer base film body 110 includes at least one of polyethylene terephthalate, polypropylene, polyethylene, polyimide, polyethylene naphthalate, polycarbonate, polyether ether ketone, cyclic polyolefin, polyarylate, polyether sulfone, polyether imide, and polyamide imide; and the composition of the metal strip 120 includes at least one of copper, aluminum, stainless steel, chromium, and nickel.

[0070] For example, the thickness of the base film 100 can be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, etc., which can also be any value in the range of 2-10 μm. The width of the metal strip 120 can be 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, or 100 mm, etc., which can also be any value in the range of 10-100 mm. The thickness of the conductive metal layer 200 can be 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, 1200 nm, 1300 nm, 1400 nm, 1500 nm, or 1600 nm, etc., which can also be any value in the range of 500-1600 nm.

[0071] In some embodiments, the metal strip 120 is provided with a first groove 121 near the end face of the polymer base film body 110, and the polymer base film body 110 is provided with a first protrusion 111 matched with the first groove 121 near the end face of the metal strip 120. By providing the first groove 121, the welding strength of the tab can be further improved, the peeling force of the tab can be effectively improved, and the resistance value of the pole piece can be reduced. Further, the width of the first groove 121 can be 500-2000 nm; the depth of the first groove 121 can be 200-2000 nm; the pitch of the first groove 121 can be 50-200 nm; and the ratio of the width to the pitch of the first groove 121 can be 1-10.

[0072] For example, the width of the first groove 121 can be 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, 1200 nm, 1300 nm, 1400 nm, 1500 nm, 1600 nm, 1700 nm, 1800 nm, 1900 nm, or 2000 nm, etc., and it can also be any value in the range of 500-2000 nm. The depth of the first groove 121 can be 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, 1200 nm, 1300 nm, 1400 nm, 1500 nm, 1600 nm, 1700 nm, 1800 nm, 1900 nm, or 2000 nm, etc., and it can also be any value in the range of 200-2000 nm. The pitch of the first groove 121 can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, or 200 nm, etc., and it can also be any value in the range of 50-200 nm. The ratio of the width to the pitch of the first groove 121 can be 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, etc., and it can also be any value in the range of 1-10.

[0073] In some embodiments, a coupling agent layer is provided between the polymer-based film body 110 and the metal strip 120. By providing the coupling agent layer between the polymer-based film body 110 and the metal strip 120, the bonding force between the polymer-based film body 110 and the metal strip 120 can be increased, thereby improving the peel strength of the tab. Further, the thickness of the coupling agent layer can be 5-100 nm. The material of the coupling agent layer can be at least one selected from the group consisting of ethenyl triperoxy tert-butyl silane, butadienyl triethoxysilane, ethenyl triethoxysilane, ethenyl trimethoxysilane, ethenyl tri(β-methoxyethoxy)silane, ethenyl silane, amino silane, and methacryloyloxy silane. These coupling agent materials can reduce the impact on the polymer-based film body 110 and the metal strip 120, and are more conducive to the anti-peeling performance of the entire current collector after the tab is welded.

[0074] For example, the thickness of the coupling agent layer can be 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, or 100 nm, or any value within the range of 5-100 nm.

[0075] In some embodiments, the two surfaces of the base film 100 are provided with second grooves 130, and the conductive metal layer 200 is provided with second protrusions 230 that cooperate with the second grooves 130. By providing the second grooves 130, the welding strength of the tab can be further improved, the peel strength of the tab can be effectively improved, and the resistance value of the tab can be reduced. Further, the width of the second grooves 130 can be 1-10 μm; the depth of the second grooves 130 can be 50-2000 nm; and the pitch of the second grooves 130 can be 1-10 μm.

[0076] For example, the width of the second groove 130 can be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, etc., and can also be any value within the range of 1-10 μm. The depth of the second groove 130 can be 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, 1200 nm, 1300 nm, 1400 nm, 1500 nm, 1600 nm, 1700 nm, 1800 nm, 1900 nm, or 2000 nm, etc., and can also be any value within the range of 50-2000 nm. The pitch of the second groove 130 can be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm, etc., and can also be any value within the range of 1-10 μm.

[0077] It should be noted that the conductive metal layer 200 is not necessarily entirely composed of metal, and some regions thereof can be composed of non-metal materials.

[0078] In some embodiments, the conductive metal layer 200 includes a conductive metal layer body 220 and a bonding layer 210 disposed between the conductive metal layer body 220 and the base film 100. By disposing the bonding layer 210, the bonding layer 210 has good bonding force with both the conductive metal layer body 220 and the base film 100, thereby increasing the bonding force between the conductive metal layer body 220 and the base film 100. Further, the bonding layer 210 is composed of at least one of chromium, nickel, nickel-chromium alloy, copper oxide, aluminum oxide, and chromium oxide, and the conductive metal layer body 220 is composed of at least one of copper, aluminum, stainless steel, chromium, and nickel.

[0079] To further increase the bonding force between the conductive metal layer body 220 and the bonding layer 210, the materials of the conductive metal layer body 220 and the bonding layer 210 can be selected to have the same element, for example, the conductive metal layer body 220 is selected to be copper, and the bonding layer 210 is selected to be copper oxide; the conductive metal layer body 220 is selected to be aluminum, and the bonding layer 210 is selected to be aluminum oxide.

[0080] In some embodiments, the thickness of the bonding layer 210 is greater than the depth of the second groove 130. In other words, the bonding layer 210 can fill the second groove 130 completely, and can exceed a certain thickness, which can be 2-100 nm. By making the thickness of the bonding layer greater than the depth of the second groove, the conductive metal layer body is bonded with the bonding layer, thereby increasing the bonding force between the entire conductive metal layer and the base film.

[0081] In some embodiments, the water content of the polymer-based film body 110 is less than or equal to 0.5%, the thermal shrinkage of the polymer-based film body 110 after baking at 150°C for 30 min is less than or equal to 5%, and the tensile elongation of the polymer-based film body 110 is greater than or equal to 34%. By controlling the water content of the polymer-based film body 110 to be less than or equal to 0.5%, the generation of impurities during the preparation of the conductive metal layer 200 can be reduced, thereby facilitating the adhesion of the conductive metal layer 200 and the base film 100. At the same time, by controlling the thermal shrinkage of the polymer-based film body 110 after baking at 150°C for 30 min to be less than or equal to 5% and the tensile elongation to be greater than or equal to 34%, the shrinkage of the base film 100 body during the subsequent preparation of the conductive metal layer 200 can be reduced, the yield of the product can be improved, and the stress between the polymer-based film body 110 and the conductive metal layer 200 can be reduced.

[0082] Figure 4 As shown in the fluid chart of the method provided by the embodiments of the present application, Figure 4 a preparation method of a current collector 1000 is provided, which comprises:

[0083] S1. combining a polymer-based film body 110 and a metal-based strip to obtain a base film 100;

[0084] In some embodiments, a first groove 121 is first formed on the metal-based strip by chemical etching, then the polymer-based film body 110 is prepared by injection molding, and the polymer-based film body 110 and the metal-based strip are combined during injection molding, for example, a base film 100 with the polymer-based film body 110 sandwiched between two metal-based strips can be obtained by injection molding the polymer-based film body 110 between the two metal-based strips. When a coupling agent layer needs to be arranged between the polymer-based film body 110 and the metal-based strip, the coupling agent can be coated on the groove side end face of the metal strip 120 before injection molding, and then the polymer-based film body 110 is formed by injection molding. Generally, the temperature of injection molding is 50-200°C.

[0085] S2. preparing a conductive metal layer 200 on the base film 100 to obtain a current collector 1000.

[0086] In some embodiments, before the conductive metal layer 200 is prepared, the method further comprises: performing shrinkage heat treatment and rewinding of the base film 100 in a vacuum environment to remove water vapor in the polymer base film body 110 and release stress, and avoiding shrinkage wrinkles and other problems in the subsequent film plating process by shrinkage heat treatment of the base film 100; performing shrinkage heat treatment and rewinding of the base film 100 after removing water vapor in an inert atmosphere to adsorb inert gas in the polymer base film body 110, isolate the water vapor in the environment of the polymer base film body 110 in the transfer process, and make the shrinkage rate of the polymer base film body 110 in the horizontal and vertical directions ≤0.1%, thereby avoiding shrinkage wrinkles and other problems in the subsequent film plating process; and finally performing corona treatment to activate the surface of the polymer base film body 110 and enhance the bonding. By performing shrinkage heat treatment and rewinding of the base film 100 in a vacuum environment and an inert atmosphere in sequence, the water vapor in the base film 100 can be reduced, thereby reducing the generation of impurities when the conductive metal layer 200 is prepared, and the adhesion of the conductive metal layer 200 and the base film 100 is improved. At the same time, since shrinkage heat treatment is performed, the shrinkage of the base film 100 body when the conductive metal layer 200 is prepared can be reduced, the yield of the product is improved, and the stress between the polymer base film body 110 and the conductive metal layer 200 can be reduced.

[0087] In some embodiments, the second groove 130 is formed on the upper and lower surfaces of the base film 100 by a chemical etching method, then the base film 100 provided with the second groove 130 is placed in a vacuum chamber, and ion cleaning is performed. The ion cleaning is ion source cleaning. The ion cleaning process gas is one of argon, hydrogen, oxygen, nitrogen and methane. Then, the binding layer 210 is plated on the two surfaces of the base film 100, the binding layer 210 fills the second groove 130 completely and slightly protrudes, ion etching is performed on the surface, and finally the conductive metal layer body 220 is plated on the binding layer 210; wherein the plating method of the binding layer 210 and the conductive metal layer body 220 can be magnetron sputtering deposition, chemical vapor deposition, pulsed laser deposition or ion plating.

[0088] The application provides an electrode plate, which comprises the current collector 1000 provided above.

[0089] The electrode plate is realized based on the current collector 1000, and the specific content of the current collector 1000 can refer to the above embodiments. Since the electrode plate adopts part or all of the technical solutions of the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0090] In some embodiments, the electrode plate further comprises a tab, and the position of the tab corresponds to the metal strip 120.

[0091] Exemplarily, the pole piece can be a positive pole piece, and the material of the electrode active material layer of the positive pole piece is selected from a positive active material. Exemplarily, the positive active material can be selected from lithium cobaltate, lithium manganate, lithium iron phosphate, or a nickel-cobalt-manganese ternary positive material.

[0092] Exemplarily, the pole piece can be a negative pole piece, and the material of the electrode active material layer of the negative pole piece is selected from a negative active material. Exemplarily, the negative active material can be selected from one or more of a silicon-based negative material and a graphite negative material.

[0093] The embodiment of the present application provides an electrochemical device, which comprises the pole piece provided above.

[0094] The electrochemical device is realized based on the pole piece, and the specific content of the pole piece can be referred to the above embodiment. Since the electrochemical device adopts part or all of the technical solutions of the above embodiment, it at least has all the beneficial effects brought by the technical solutions of the above embodiment, which will not be repeated here.

[0095] Exemplarily, the electrochemical device further comprises a separator, and the separator is arranged between the positive pole piece and the negative pole piece.

[0096] Exemplarily, the electrochemical device further comprises an electrolyte, and the electrolyte can be an electrolyte solution or a solid-state electrolyte.

[0097] The present application will be further described in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. The experimental methods not specified in the following embodiments are generally determined according to the national standards. If there is no corresponding national standard, the international standard, the conventional condition, or the condition suggested by the manufacturer is used.

[0098] Embodiment 1

[0099] A current collector, the structure of which is shown in Figure 1 is prepared by the following steps:

[0100] (1) A copper metal strip 120 with a thickness of 4.5 um and a width of 20 mm is selected, and a copper chloride etching solution is used to etch the upper and lower surfaces and one side surface of the copper metal strip 120 to generate grooves, i.e., a first groove 121 and a second groove 130. The width of the first groove 121 is 1000 nm, the depth is 300 nm, and the groove spacing is 500 nm. The width of the second groove 130 is 2000 nm, the depth is 300 nm, and the groove spacing is 250 nm. The coupling agent, i.e., vinyl triperoxy-tert-butylsilane, is sprayed on the end surface of the first groove 121 of the metal strip 120 to form a coupling agent layer.

[0101] (2) Two copper metal strips 120 are placed opposite each other with the first groove 121, with a spacing of 1000 mm. The ambient temperature is raised to 170°C. Polypropylene injection molding is performed between the two copper metal strips 120 to fill the first groove 121, thereby generating a polypropylene polymer (PP) film and obtaining a base film 100.

[0102] (3) At an ambient temperature of 40°C, perchloric acid was used to chemically etch the upper and lower surfaces of the PP film to form grooves 2000 nm wide and 300 nm deep on the upper and lower surfaces, respectively, as the second groove 130.

[0103] (4) The base film 100 is rewound in a vacuum chamber at a temperature of 80°C and a rewinding speed of 10 m / min. After the first rewinding is completed, argon gas is introduced into the vacuum chamber to maintain the temperature at 80°C, and the film is rewound again at a speed of 10 m / min.

[0104] (5) The base film 100 is subjected to corona treatment with a power of 10KW and a linear velocity of 20m / min.

[0105] (6) Place the base film 100 in a vacuum magnetron sputtering coating equipment, evacuate the equipment chamber to a background vacuum lower than 3E3Pa, set the temperature to 20°C, introduce oxygen to maintain the pressure at 0.07Pa; apply a bias voltage of 600V to the sample holder for ion etching cleaning, with a cleaning current of 0.5A and a cleaning time of 15min, thereby removing dirt and impurities from the surface of the base film 100, increasing the surface roughness of the base film 100, and enhancing the adhesion between the base film 100 and the bonding layer 210.

[0106] (7) Maintain the temperature inside the equipment chamber unchanged, introduce oxygen to maintain the pressure at 0.15 Pa; use vacuum magnetron sputtering to deposit bonding layer 210 (CuO coating) on ​​the upper and lower surfaces of the base film 100 and the second groove 130 respectively, with a deposition current of 10 A, a deposition time of 3 min, and a bonding layer 210 thickness of 5 nm.

[0107] (8) Maintain the temperature inside the equipment chamber constant, introduce argon gas to maintain the gas pressure at 0.07Pa; apply a bias voltage of 600V to the sample holder for ion etching cleaning, cleaning current of 0.5A, cleaning time of 10min, thereby increasing the surface roughness of the bonding layer 210 and increasing the bonding force between the bonding layer 210 and the conductive metal layer body 220.

[0108] (9) Maintain a constant temperature inside the equipment chamber and introduce argon gas to maintain a pressure of 0.12 Pa; use vacuum magnetron sputtering to deposit conductive metal body 220 (Cu coating) on ​​the outer surfaces of the two bonding layers 210 respectively. The deposition current is 20 A, the deposition time is 60 min, and the thickness of the conductive metal body 220 is 1100 nm.

[0109] The collector 1000 can be obtained by discharging the device.

[0110] Example 2

[0111] A collector with the structure as shown in Figure 2 is prepared by the following steps:

[0112] (1) A copper metal strip 120 with a thickness of 4.5 um and a width of 20 mm is selected, and a second groove 130 is formed on the upper and lower surfaces of the copper metal strip 120 by etching using a copper chloride etching solution. The second groove 130 has a width of 2000 nm, a depth of 300 nm, and a groove spacing of 250 nm.

[0113] (2) The two copper metal strips 120 are placed with a spacing of 1000 mm, and the ambient temperature is raised to 170°C. Polypropylene injection is performed between the two copper metal strips 120 to form a polypropylene polymer (PP) film, thereby obtaining a base film 100.

[0114] (3) The upper and lower surfaces of the PP film are chemically etched using perchloric acid at an ambient temperature of 40°C to form a groove with a width of 2000 nm and a depth of 300 nm on each surface as the second groove 130.

[0115] (4) The base film 100 is rewound in a vacuum chamber at a temperature of 80°C and a rewinding film speed of 10 m / min. After the first rewinding is completed, argon gas is introduced into the vacuum chamber while maintaining the temperature at 80°C, and the film is rewound again at a speed of 10 m / min.

[0116] (5) The base film 100 is subjected to corona treatment at a corona power of 10 KW and a line speed of 20 m / min.

[0117] (6) The base film 100 is placed in a vacuum magnetron sputtering coating device, the device chamber is evacuated to a background vacuum of less than 3E3 Pa, the temperature is raised to 20°C, and oxygen is introduced to maintain the gas pressure at 0.07 Pa. A bias voltage of 600V is applied to the sample holder for ion etching cleaning, the cleaning current is 0.5A, and the cleaning time is 15 min. This removes dirt and impurities from the surface of the base film 100, increases the surface roughness of the base film 100, and enhances the adhesion between the base film 100 and the bonding layer 210.

[0118] (7) The temperature in the device chamber is maintained, and oxygen is introduced to maintain the gas pressure at 0.15 Pa. A bonding layer 210 (CuO coating) is deposited on the upper and lower surfaces of the base film 100 and the second groove 130 by vacuum magnetron sputtering coating method, with a deposition current of 10A and a deposition time of 3 min. The thickness of the bonding layer 210 is 5 nm.

[0119] (8) maintain the temperature in the chamber of the equipment unchanged, and introduce argon to maintain the pressure at 0.07 Pa; apply a bias voltage of 600 V to the sample holder to perform ion etching cleaning, the cleaning current is 0.5 A, and the cleaning time is 10 min, so as to increase the surface roughness of the bonding layer 210, and increase the bonding force between the bonding layer 210 and the conductive metal layer body 220.

[0120] (9) maintain the temperature in the chamber of the equipment unchanged, and introduce argon to maintain the pressure at 0.12 Pa; use a vacuum magnetron sputtering coating method to respectively coat the conductive metal layer body 220 (Cu coating) on the outer surfaces of the two bonding layers 210. The deposition current is 20 A, the deposition time is 60 min, and the thickness of the conductive metal layer body 220 is 1100 nm.

[0121] The sample is taken out from the equipment, and the current collector 1000 is obtained.

[0122] Example 3

[0123] A current collector, as shown in Figure 3 , is prepared by the following steps:

[0124] (1) select a copper metal strip 120 with a thickness of 4.5 um and a width of 20 mm, place the copper metal strip 120 at a distance of 1000 mm, increase the ambient temperature to 170℃, and perform polypropylene injection between the two copper metal strips 120 to fill the first groove 121, generate a polypropylene polymer (PP) film, and obtain a base film 100.

[0125] (2) re-wind the base film 100 in a vacuum chamber at a temperature of 80℃, and the rewinding film speed is 10 m / min. After the first rewinding is completed, introduce argon into the vacuum chamber, maintain the temperature at 80℃, and re-wind at a speed of 10 m / min.

[0126] (3) perform corona treatment on the base film 100, the corona power is 10 KW, and the linear speed is 20 m / min.

[0127] (4) place the base film 100 in a vacuum magnetron sputtering coating equipment, evacuate the chamber of the equipment to a base vacuum lower than 3E3 Pa, and the temperature is 20℃, introduce oxygen to maintain the pressure at 0.07 Pa; apply a bias voltage of 600 V to the sample holder to perform ion etching cleaning, the cleaning current is 0.5 A, and the cleaning time is 15 min, so as to remove dirt and impurities on the surface of the base film 100, increase the surface roughness of the base film 100, and enhance the adhesion between the base film 100 and the bonding layer 210.

[0128] (5) maintain the temperature in the chamber of the equipment unchanged, and introduce oxygen to maintain the gas pressure at 0.15 Pa; use the vacuum magnetron sputtering coating method to coat the binding layer 210 (CuO coating layer) on the upper and lower surfaces of the base film 100, the deposition current is 10 A, the deposition time is 3 min, and the thickness of the binding layer 210 is 5 nm.

[0129] (6) maintain the temperature in the chamber of the equipment unchanged, and introduce argon to maintain the gas pressure at 0.07 Pa; perform ion etching cleaning by applying a bias voltage of 600 V to the sample holder, the cleaning current is 0.5 A, the cleaning time is 10 min, so as to increase the surface roughness of the binding layer 210 and increase the binding force between the binding layer 210 and the conductive metal layer body 220.

[0130] (7) maintain the temperature in the chamber of the equipment unchanged, and introduce argon to maintain the gas pressure at 0.12 Pa; use the vacuum magnetron sputtering coating method to coat the conductive metal layer body 220 (Cu coating layer) on the outer surfaces of the two binding layers 210. The deposition current is 20 A, the deposition time is 60 min, and the thickness of the conductive metal layer body 220 is 1100 nm.

[0131] The current collector 1000 can be obtained by taking the sample out of the equipment.

[0132] Example 4

[0133] A current collector, as shown in Figure 1 , is prepared by the following steps:

[0134] (1) select a copper metal strip 120 with a thickness of 4.5 um and a width of 20 mm, and use copper chloride etching solution to etch the upper and lower surfaces and one side surface of the copper metal strip 120 to generate grooves, i.e., a first groove 121 and a second groove 130. The width of the first groove 121 is 1000 nm, the depth is 300 nm, and the groove spacing is 500 nm; the width of the second groove 130 is 2000 nm, the depth is 300 nm, and the groove spacing is 250 nm.

[0135] (2) place two copper metal strips 120 with the first groove 121 facing each other with a spacing of 1000 mm, and increase the ambient temperature to 170°C, and perform polypropylene injection molding between the two copper metal strips 120 to fill the first groove 121, to generate a polypropylene polymer (PP) film, to obtain a base film 100.

[0136] (3) use perchloric acid to chemically etch the upper and lower surfaces of the PP film at an ambient temperature of 40°C, to form a groove with a width of 2000 nm and a depth of 300 nm on each of the upper and lower surfaces as the second groove 130.

[0137] (4) The base film 100 is rewound in the vacuum chamber at a temperature of 80°C and a rewinding speed of 10 m / min. After the first rewinding, argon is introduced into the vacuum chamber to maintain the temperature at 80°C, and the film is rewound at a speed of 10 m / min.

[0138] (5) The base film 100 is subjected to corona treatment at a corona power of 10 KW and a linear speed of 20 m / min.

[0139] (6) The base film 100 is placed in a vacuum magnetron sputtering coating device, the chamber of which is evacuated to a base vacuum of less than 3E3 Pa, and the temperature is maintained at 20°C. Oxygen is introduced to maintain the gas pressure at 0.07 Pa. A bias voltage of 600 V is applied to the sample holder for ion etching cleaning, the cleaning current is 0.5 A, and the cleaning time is 15 min. In this way, the dirt and impurities on the surface of the base film 100 are removed, the surface roughness of the base film 100 is increased, and the adhesion between the base film 100 and the bonding layer 210 is enhanced.

[0140] (7) The temperature in the chamber of the device is maintained unchanged, and oxygen is introduced to maintain the gas pressure at 0.15 Pa. A bonding layer 210 (CuO coating) is deposited on the upper and lower surfaces of the base film 100 and the second groove 130 by vacuum magnetron sputtering coating method, the deposition current is 10 A, the deposition time is 3 min, and the thickness of the bonding layer 210 is 5 nm.

[0141] (8) The temperature in the chamber of the device is maintained unchanged, and argon is introduced to maintain the gas pressure at 0.07 Pa. A bias voltage of 600 V is applied to the sample holder for ion etching cleaning, the cleaning current is 0.5 A, and the cleaning time is 10 min. In this way, the surface roughness of the bonding layer 210 is increased, and the adhesion between the bonding layer 210 and the conductive metal layer body 220 is increased.

[0142] (9) The temperature in the chamber of the device is maintained unchanged, and argon is introduced to maintain the gas pressure at 0.12 Pa. A conductive metal layer body 220 (Cu coating) is deposited on the outer surfaces of the two bonding layers 210 by vacuum magnetron sputtering coating method. The deposition current is 20 A, the deposition time is 60 min, and the thickness of the conductive metal layer body 220 is 1100 nm.

[0143] The current collector 1000 is taken out of the device.

[0144] Comparative Example 1

[0145] A current collector having a structure as shown in Figure 5 was prepared by the following steps:

[0146] (1) A polypropylene polymer (PP) film was selected as the base film 100, with a thickness of 4.5 um and a width of 1020 mm.

[0147] (2) The base film 100 is rewound in the vacuum chamber at a temperature of 80°C and a rewinding speed of 10 m / min. After the first rewinding, argon is introduced into the vacuum chamber to maintain the temperature at 80°C, and the film is rewound at a speed of 10 m / min.

[0148] (3) The base film 100 is subjected to corona treatment at a corona power of 10 KW and a linear speed of 20 m / min.

[0149] (4) The base film 100 is placed in a vacuum magnetron sputtering coating device, the chamber of which is evacuated to a base vacuum of less than 3E3 Pa, and the temperature is maintained at 20°C. Oxygen is introduced to maintain the gas pressure at 0.07 Pa. A bias voltage of 600 V is applied to the sample holder for ion etching cleaning, with a cleaning current of 0.5 A and a cleaning time of 15 min. This removes dirt and impurities on the surface of the base film 100, increases the surface roughness of the base film 100, and enhances the adhesion between the base film 100 and the bonding layer 210.

[0150] (5) The temperature in the chamber of the device is maintained unchanged, and oxygen is introduced to maintain the gas pressure at 0.15 Pa. Vacuum magnetron sputtering coating is used to deposit a bonding layer 210 (CuO coating) on the upper and lower surfaces of the base film 100, with a deposition current of 10 A and a deposition time of 3 min. The thickness of the bonding layer 210 is 5 nm.

[0151] (6) The temperature in the chamber of the device is maintained unchanged, and argon is introduced to maintain the gas pressure at 0.07 Pa. A bias voltage of 600 V is applied to the sample holder for ion etching cleaning, with a cleaning current of 0.5 A and a cleaning time of 10 min. This increases the surface roughness of the bonding layer 210, and increases the adhesion between the bonding layer 210 and the conductive metal layer body 220.

[0152] (7) The temperature in the chamber of the device is maintained unchanged, and argon is introduced to maintain the gas pressure at 0.12 Pa. Vacuum magnetron sputtering coating is used to deposit a conductive metal layer body 220 (Cu coating) on the outer surfaces of the two bonding layers 210. The deposition current is 20 A, the deposition time is 60 min, and the thickness of the conductive metal layer body 220 is 1100 nm.

[0153] The sample is taken out of the device, and the current collector 1000 is obtained.

[0154] Comparative Example 2

[0155] A current collector, as shown in Figure 5 , is prepared by the following steps:

[0156] (1) A polypropylene polymer (PP) film is selected as the base film 100, with a thickness of 4.5 um and a width of 1020 mm.

[0157] (2) Corona treatment of the base film 100, corona power 10 KW, line speed 20 m / min.

[0158] (3) The base film 100 is placed in a vacuum magnetron sputtering coating equipment, the chamber is vacuumed to a background vacuum lower than 3E3 Pa, the temperature is 20℃, oxygen is introduced to maintain the gas pressure at 0.07 Pa; a bias of 600 V is applied to the sample holder for ion etching cleaning, the cleaning current is 0.5 A, the cleaning time is 15 min, so as to remove dirt and impurities on the surface of the base film 100, increase the surface roughness of the base film 100, and enhance the adhesion of the base film 100 and the bonding layer 210.

[0159] (4) The temperature in the chamber of the equipment is maintained unchanged, oxygen is introduced to maintain the gas pressure at 0.15 Pa; vacuum magnetron sputtering coating method is adopted to coat the bonding layer 210 (CuO coating) on the upper and lower surfaces of the base film 100, the deposition current is 10 A, the deposition time is 3 min, and the thickness of the bonding layer 210 is 5 nm.

[0160] (5) The temperature in the chamber of the equipment is maintained unchanged, argon is introduced to maintain the gas pressure at 0.07 Pa; a bias of 600 V is applied to the sample holder for ion etching cleaning, the cleaning current is 0.5 A, the cleaning time is 10 min, so as to increase the surface roughness of the bonding layer 210, and increase the adhesion of the bonding layer 210 and the conductive metal layer body 220.

[0161] (6) The temperature in the chamber of the equipment is maintained unchanged, argon is introduced to maintain the gas pressure at 0.12 Pa; vacuum magnetron sputtering coating method is adopted to coat the conductive metal layer body 220 (Cu coating) on the outer surfaces of the two bonding layers 210. The deposition current is 20 A, the deposition time is 60 min, and the thickness of the conductive metal layer body 220 is 1100 nm.

[0162] The current collector 1000 is obtained from the equipment.

[0163] The current collectors provided by Examples 1 to 4 and Comparative Examples 1 to 2 are respectively cut into long strips with a length of 10 cm and a width of 2 cm, and are respectively ultrasonic spot welded with nickel tabs with a thickness of 0.1 mm and a width of 1 cm. The welding parameters are as follows: (1) amplitude: 20 kHz; (2) welding pressure: 0.4 MPa; (3) welding time: 20 um; (4) welding energy: 1 kJ; (5) welding head size: rectangular, area 20 mm 2 . Five welding test samples are respectively prepared for each current collector of each example or comparative example, and the resistance test and the peel force test are respectively performed on each welding test sample using a multimeter and a tensile testing machine, and the test results are shown in Table 1.

[0164] Table 1 Resistance and adhesion test results of welding samples of examples

[0165] Resistance / mΩ Peeling force / (N / cm) Example 1 3.1±0.2 2.2±0.2 Example 2 3.4±0.1 1.9±0.3 Example 3 3.2±0.1 1.5±0.3 Example 4 3.3±0.3 2.0±0.4 Comparative Example 1 12.4±0.5 0.5±0.1 Comparative Example 2 12.6±0.4 0.4±0.1

[0166] As can be seen from Table 1, the first groove and the second groove can effectively improve the bonding strength of the current collector and the welding tab and reduce the resistance. In addition, through the design of the first groove and the second groove, the metal strip makes the metal layers on both sides of the current collector conductive, so that the current collector is suitable for pure copper foil or pure aluminum foil tab welding equipment, effectively solves the problem of introducing the composite current collector into the battery production line for welding, and reduces the investment of battery manufacturers in the equipment end.

[0167] The current collectors provided in Examples 1 to 3 and Comparative Examples 1 to 2 were respectively cut into long strips with a length of 15 cm and a width of 2 cm, and were tested by the 180° peeling method test through a tensile testing machine to detect the bonding force of the plated metal layer. The test results are shown in Table 2.

[0168] Table 2 Bonding force of plated layer of examples

[0169] Bonding force / (N / cm) Example 1 12.4±0.2 Example 2 12.0±0.1 Example 3 8±0.3 Comparative Example 1 7.6±0.4 Comparative Example 2 5.1±0.3

[0170] As can be seen from Table 2, through the design of the first groove and the second groove, the bonding force of the plated layer and the base film in the current collector is effectively improved. By comparing Comparative Example 1 and Comparative Example 2, by performing heat shrinkage treatment on the base film before plating the metal layer, the shrinkage rate of the base material is ≤0.1%, which effectively reduces the stress between the plated layer and the base material, and can reduce the water vapor content in the base film, effectively reducing the possibility of impurities generated in the bonding surface during plating, and reducing the stress between the plated layer and the base material, so that the bonding force between the plated layer and the base material of the composite current collector is significantly enhanced.

[0171] The above description is merely a specific implementation of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A current collector characterized by comprising: The current collector comprises a base film and two conductive metal layers distributed along a thickness direction X, the base film is arranged between the two conductive metal layers, the base film comprises a polymer base film body and a metal strip distributed along a film surface direction Y, and the metal strip is arranged on at least one side of the polymer base film body.

2. The current collector of claim 1, wherein The metal strip is provided with a first groove near an end surface of the polymer base film body, and the polymer base film body is provided with a first protrusion matched with the first groove near an end surface of the metal strip.

3. The current collector of claim 2, wherein The metal strip is provided with a plurality of first grooves, and a ratio of a width of the first groove to a pitch of the first groove along the thickness direction X is 1-10.

4. The current collector according to claim 2 or 3, characterized by The width of the first groove is 500-2000 nm; and / or The depth of the first groove is 200-2000 nm; and / or The metal strip is provided with a plurality of first grooves, and a pitch of the first groove is 50-200 nm.

5. The current collector of claim 1, wherein A coupling agent layer is arranged between the polymer base film body and the metal strip.

6. The current collector of claim 5, wherein The thickness of the coupling agent layer is 5-100 nm.

7. The current collector of claim 5, wherein The material of the coupling agent layer is vinyl triperoxy tert-butyl silane, butadiene triethoxysilane, vinyl triethoxysilane, vinyl trimethoxysilane, vinyl tri(β-methoxyethoxy)silane, vinyl silane, amino silane or methacryloyloxy silane.

8. The current collector of claim 1, wherein Two surfaces of the base film are provided with second grooves, and the conductive metal layer is provided with second protrusions matched with the second grooves near side surfaces of the base film.

9. The current collector of claim 8, wherein The width of the second groove is 1-10 μm; and / or The depth of the second groove is 50-2000 nm; and / or The pitch of the second groove is 1-10 μm.

10. The current collector of claim 1, wherein The conductive metal layer comprises a conductive metal layer body and a bonding layer, and the bonding layer is arranged between the conductive metal layer body and the base film.

11. The current collector of claim 10, wherein Two surfaces of the base film are provided with second grooves, and the thickness of the bonding layer is greater than the depth of the second groove.

12. The current collector of claim 1, wherein The water content of the polymer base film body is below 0.5%; and / or The heat shrinkage rate of the polymer base film body after being baked at 150°C for 30 min is below 5%; and / or The elongation at break of the polymer base film body is above 34%.

13. The current collector of claim 1, wherein The thickness of the base film is 2-10 μm; and / or The width of the metal strip is 10-100 mm; and / or The thickness of the conductive metal layer is 500-1600 nm.

14. The current collector of claim 1, wherein The component of the polymer base film body is polyethylene terephthalate, polypropylene, polyethylene, polyimide, polyethylene naphthalate, polycarbonate, polyether ether ketone, cyclic polyolefin, polyarylate, polyether sulfone, polyether imide or polyamide imide; and / or The component of the metal strip is copper, aluminum, stainless steel, chromium or nickel; and / or The component of the bonding layer of the conductive metal layer is chromium, nickel, nickel-chromium alloy, copper oxide, aluminum oxide or chromium oxide; and / or The component of the conductive metal layer body of the conductive metal layer is copper, aluminum, stainless steel, chromium or nickel.

15. A pole piece characterized by, The pole piece comprises the current collector according to any one of claims 1-14.

16. The pole piece of claim 15, wherein The pole piece further comprises a tab, and the tab is located at a position corresponding to the metal strip.

17. An electrochemical device, characterized by, The electrochemical device includes the electrode sheet of any one of claims 15 to 16.

Images