Device and method for testing interface bonding force of composite current collector

Abstract

The invention provides a device and a method for testing the interface bonding force of a composite current collector. The device for testing the interface bonding force of the composite current collector comprises a testing platform, a fixing tool, a drawing tool and a curing plate, a to-be-tested sample is laid on the surface of the test platform; the fixing tool comprises a first bearing cross beam, a second bearing cross beam and a plurality of limiting parts, the first bearing cross beam and the second bearing cross beam are detachably connected with the testing platform and used for fixing a to-be-tested sample, and the two ends of each limiting part are movably connected with the first bearing cross beam and the second bearing cross beam respectively; the limiting parts are provided with detection areas, or every two adjacent limiting parts are spliced to form a detection area; the drawing tool is positioned in the detection area and is connected with the sample to be detected; the curing plate and the test platform are arranged in a stacked mode, and the curing plate is used for clamping and curing the drawing tool. The shape of the to-be-tested sample is not limited, detection of the specified area of the sample is achieved, the to-be-tested sample is evenly stressed, and the test success rate is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesion testing and relates to a composite current collector interface bonding force testing device and method. Background Art

[0002] As an important component of lithium batteries, current collectors have a significant impact on the application and performance of lithium batteries. Traditional metal (copper foil and aluminum foil) current collectors have bottlenecks in performance and cost iterations and cannot meet the performance and cost requirements of lithium batteries. Composite current collectors are currently the most promising new current collector material to replace traditional metal current collectors. Compared with traditional metal current collectors, they have the advantages of high safety, low manufacturing cost, and high energy density.

[0003] The composite current collector generally presents a "sandwich" film structure of "metal conductive layer-polymer material (base film)-metal conductive layer". This structural optimization introduces the base film-metal coating interface, and the interface bonding directly affects the long-term stable use of the composite current collector in lithium batteries. Therefore, it is necessary to use a suitable test method to more realistically characterize the magnitude of the composite current collector's interfacial bonding force to ensure its normal use in lithium batteries.

[0004] The existing test method for composite films in the reference standard GB / T 2792-2014 is mainly the peeling method, which is to stick the tape or thermal adhesive film (need to be hot pressed) on the surface of the composite current collector, and then peel the sample at 90° or 180°, and the value displayed by the tensile machine is used as the interface bonding force between the metal layer and the substrate. However, this method has many requirements for sample preparation. For example, when using tape for testing, the adhesive force and uniformity of the tape itself are high, and the gas must be effectively discharged when rolling the sample; when using thermal adhesive film for testing, the pressure and temperature must be appropriate, but the hot pressing process must ensure that the current collector and the thermal adhesive film have no deformation and wrinkles. After being heated, the thermal adhesive film must be evenly attached to the surface of the current collector, and the bubbles on the two surfaces of the bonded surface must be discharged. At the same time, the test strips are cut according to the width requirements, and the edge flatness must be ensured to avoid the impact of edge damage on the results. Secondly, in the actual implementation of the peeling method at this stage, it is often impossible to effectively peel, that is, the problem of being unable to peel or peeling discontinuously reduces the overall test efficiency. In addition, the traditional peeling method is limited in the shape of the test sample and has low applicability.

[0005] CN220961177U adopts the stretching method. First, the four corners of the film are fixed by the equipment, and then the glue gun is used to melt the hot melt adhesive and drip it in the middle of the current collector to be tested. The hot melt adhesive is squeezed flat by the pressure block provided by the equipment. After cooling and solidification, a tensile force is applied in the vertical direction, and the read value is the interface peeling force. However, this method requires the hot melt adhesive to be melted into a liquid state first. Bubbles are prone to occur during the melting process, and the test efficiency is low. Only one sample can be tested at a time, and each test requires heating and replacement of the pressure block, and the operation steps are complicated. In addition, if the sample is deformed greatly, since the equipment-matching clamps only fix the four corners, the sample is subjected to uneven force, which can easily cause stretching failure and affect the test results.

[0006] Therefore, there is a need to provide a more effective test method for characterizing the interfacial bonding force of composite current collectors. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a composite current collector interface bonding force testing device and method, which is not limited to the shape of the sample to be tested, can test multiple samples at the same time, realize the detection of designated areas of the sample, and during the stretching process, the force is evenly applied on all sides of the sample to be tested, thereby improving the test success rate.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides a composite current collector interface bonding force testing device, including a testing platform, a fixing tool, a pulling tool and a curing plate; the surface of the testing platform is paved with a sample to be tested; the fixing tool includes a first supporting beam, a second supporting beam and a plurality of limiting parts, the first supporting beam and the second supporting beam are arranged side by side on the sample to be tested, and are independently and detachably connected to the testing platform for fixing the sample to be tested, the two ends of the limiting part are respectively movably connected to the first supporting beam and the second supporting beam, a detection area is opened on the limiting part or two adjacent limiting parts are spliced ​​to form a detection area; the pulling tool is located in the detection area and is connected to the sample to be tested; the curing plate and the testing platform are stacked and arranged for positioning and curing the pulling tool.

[0010] The present invention lays the sample to be tested flat on the test platform, first uses the first supporting beam and the second supporting beam to fix the sample to be tested around, and adjusts the limit part to form multiple detection areas, and then assembles the drawing tool, and uses the curing plate to clamp and cure, so that the sample to be tested is evenly stressed during the stretching process, so that the test interface is effectively separated, and the test efficiency is improved. The present invention can also perform rapid tests on multiple areas at the same time by adjusting the number and position of the limit parts, and can also test the specified area of ​​the sample to be tested, and can also analyze and test the influence law of sample deformation, which greatly improves the applicability and flexibility of the device.

[0011] The invention has a wide application range and can be used not only for testing the interface bonding strength of composite current collectors, but also for testing the bonding strength between any other base film and coating, and for measuring the bonding strength between different materials.

[0012] As a preferred technical solution of the present invention, a pre-bonding layer is provided on the surface of the test platform.

[0013] Preferably, the pre-bonding layer includes a plurality of bonding parts, and the plurality of bonding parts are evenly distributed on a surface of one side of the test platform on which the sample to be tested is laid.

[0014] Preferably, at least part of the bonding portions are arranged at intervals on the edge of the test platform.

[0015] The pre-bonding layer of the present invention can be used to preliminarily fix the sample to be tested, thereby preventing relative movement from occurring during the subsequent assembly process of the fixing tooling, thereby affecting the test effect.

[0016] Preferably, the test platform is connected by snap-fitting, riveting or bolting the first supporting beam and the second supporting beam respectively.

[0017] As a preferred technical solution of the present invention, the detection area is in any one of polygonal, circular, semicircular or elliptical shapes, or a combination of at least two of them.

[0018] The present invention first determines the test site and size, and then adjusts the number and shape of the detection area to meet different test requirements. It is not limited to the shape of the sample and is not only suitable for testing large-sized samples, but also for testing small-sized or designated area samples, with high flexibility.

[0019] Preferably, the first supporting beam, the second supporting beam and the limiting portion are independently spliced ​​structures or telescopic structures.

[0020] The present invention can adjust the lengths of the first supporting crossbeam, the second supporting crossbeam and the limiting portion according to the sizes of different samples to be tested, so as to ensure that the four sides of the sample to be tested are evenly stressed during the stretching process.

[0021] Preferably, both ends of the limiting portion are connected to the first supporting beam and the second supporting beam by any one of sliding connection, rivet connection, slot connection, bolt connection or interference connection, or a combination of at least two of them.

[0022] The present invention forms detection areas with different shapes, sizes and numbers by adjusting the position of the limiting part to meet the test requirements.

[0023] Preferably, a slide rail is independently provided on the surface of one side of the first supporting crossbeam and the second supporting crossbeam which are close to each other, and sliders are independently provided at both ends of the limiting portion, and the sliders are movably connected to the slide rail.

[0024] Preferably, the first supporting crossbeam, the second supporting crossbeam and a surface of the limiting portion on one side close to the sample to be tested are independently provided with limiting gaskets.

[0025] The first supporting crossbeam, the second supporting crossbeam and the limiting part of the present invention can all be bonded to fix the sample to be tested, thereby reducing the slippage of the sample during the drawing process.

[0026] Preferably, the first supporting beam and the second supporting beam are independently rectangular parallelepiped structures.

[0027] As a preferred technical solution of the present invention, the first supporting beam, the second supporting beam and the limiting portion have the same thickness.

[0028] Preferably, the thickness of the first supporting beam, the second supporting beam and the limiting portion are independently 1 to 5 mm, for example, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm, but are not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 2 to 4 mm.

[0029] Preferably, the total area of ​​the sample to be tested covered by the first supporting beam and the second supporting beam is 6% to 30% of the area of ​​the sample to be tested, for example, it can be 6%, 8%, 10%, 15%, 20%, 23%, 25%, 28% or 30%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are equally applicable.

[0030] Preferably, the width of the first supporting beam and the second supporting beam are independently 2 to 10 mm, for example, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm, but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 4 to 6 mm.

[0031] Preferably, the thickness of the limiting gasket is 0.5 to 2 mm, for example, it can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.2 mm, 1.5 mm, 1.6 mm, 1.8 mm or 2 mm, but it is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 0.5 to 1 mm.

[0032] Preferably, the material of the fixing tool includes any one of stainless steel, ceramic, plastic and wood, or a combination of at least two of them.

[0033] As a preferred technical solution of the present invention, the drawing tool includes a first end, a connecting portion and a second end connected in sequence along the axial direction, and the second end is at least partially located inside the detection area along the axial direction and connected to the sample to be tested.

[0034] In the present invention, the first end is used to connect the tension equipment, and the second end is used to connect the sample to be tested. During the test, the pulling tool is pulled out from one side of the first end. Due to the strong bonding effect between the second end and the sample to be tested, the surface attached to the outermost layer of the sample to be tested is separated from other interfaces.

[0035] Preferably, a maximum linear length of an orthographic projection of the first end in the detection zone is smaller than a maximum linear length of an orthographic projection of the second end in the detection zone.

[0036] Preferably, the connecting portion has an upper end surface and a lower end surface, the upper end surface and the lower end surface are respectively connected to the first end portion and the second end portion, a gap is left between the outer edge of the upper end surface and the outer edge of the first end portion, and the outer edge of the lower end surface is flush with the outer edge of the second end portion.

[0037] Preferably, the connecting portion has a necking transition, an inclined smooth transition or a curved smooth transition.

[0038] Preferably, a cured adhesive layer is provided on a surface of the second end portion close to the sample to be tested.

[0039] As a preferred technical solution of the present invention, after the second end is placed in the detection area, the distance between the outer edge of the second end and the edge of the detection area is 2 to 5 mm, for example, it can be 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] Preferably, the maximum linear length of the positive projection of the second end in the detection area is 5 to 50 mm, for example, it can be 5 mm, 8 mm, 10 mm, 15 mm, 16 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm or 50 mm, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 10 to 30 mm.

[0041] Preferably, the height of the connecting portion is 10 to 50 mm, for example, it can be 10 mm, 15 mm, 16 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm or 50 mm, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 20 to 30 mm.

[0042] Preferably, the length of the gap between the outer edge of the upper end surface of the connecting portion and the outer edge of the first end portion is 1 to 10 mm, for example, it can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0043] Preferably, the material of the drawing tool includes any one of stainless steel, ceramic, plastic and wood, or a combination of at least two of them.

[0044] As a preferred technical solution of the present invention, a plurality of accommodating areas are provided on the surface of the curing plate, and the accommodating areas correspond to the detection areas, so that the accommodating areas are engaged with the second end of the drawing tool.

[0045] Preferably, the outer edge of the curing plate is flush with the outer edge of the testing platform.

[0046] Preferably, the maximum linear length of the orthographic projection of the first end in the detection area is less than the maximum linear length of the accommodating area and less than the maximum linear length of the orthographic projection of the second end in the detection area.

[0047] In the present invention, the size of the curing plate is consistent with the size of the test platform. After the curing plate is aligned and placed on the test platform, the positions of the accommodating area and the detection area correspond and are coaxially arranged. The accommodating area passes through the drawing tool to cure the second end, and after the curing is completed, the curing plate is removed and tested again.

[0048] In a second aspect, the present invention provides a method for testing the interfacial bonding strength of a composite current collector, wherein the testing method adopts the interfacial bonding strength testing device of the composite current collector according to the first aspect, and the testing method comprises:

[0049] (1) Determine the test requirements and select the test platform, fixture, drawing fixture and curing plate;

[0050] (2) Laying the sample to be tested on the surface of the test platform, fixing the sample to be tested on the test platform using a fixing tool, and forming a test area that meets the test requirements;

[0051] (3) then assembling the drawing tool and fixing the drawing tool on the sample to be tested in the testing area;

[0052] (4) Use a curing plate to fix the pulling tool in place and then remove the curing plate to perform a pulling force test.

[0053] As a preferred technical solution of the present invention, the test requirements include: testing the uniformity of the binding force of different regions of the sample to be tested or testing the binding force of a specified region of the sample to be tested.

[0054] Preferably, the testing method comprises: using a degassing treated composite adhesive to bond and fix the drawing tool to the surface of the sample to be tested in the testing area.

[0055] Preferably, the composite adhesive comprises a mixture of a main adhesive and a curing agent.

[0056] Preferably, the main adhesive includes any one of epoxy adhesive, phenolic adhesive, acrylate adhesive or polyurethane adhesive, or a combination of at least two of them.

[0057] Preferably, the curing agent includes any one of aliphatic polyamine, polyamide, tertiary amine and polythiol, or a combination of at least two of them.

[0058] Preferably, the solidification time of the clamping position is 6 to 15 minutes, for example, it can be 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes or 5 minutes, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0059] Preferably, the pressure of the locking and curing is 0.05-0.3 MPa, for example, it can be 0.05 MPa, 0.08 MPa, 0.1 MPa, 0.15 MPa, 0.18 MPa, 0.2 MPa, 0.23 MPa, 0.25 MPa, 0.28 MPa or 0.3 MPa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0060] As a preferred technical solution of the present invention, the pull-out force test adopts a tensile device.

[0061] Preferably, the test method further comprises: determining whether the pull-out test result is a valid pull-out, and when it is determined to be a valid pull-out, terminating the test; otherwise, making adjustments after clarifying the cause of the ineffective pull-out, and then retesting.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] The present invention provides a composite current collector interface bonding force testing device and method, which are reasonably designed and easy to operate, and can effectively fix the sample to be tested so that the sample is evenly stressed on all sides during stretching, thereby ensuring the success rate of pulling. The present invention has high flexibility and is not limited to the shape, quantity and size of the sample to meet different testing requirements. It also has wide applicability and can quickly test multiple test areas to determine the uniformity of the bonding force of different positions of the material. It can also test the bonding force of a specified area, and can also analyze the influence of the deformation of the test film interface, thereby improving the overall testing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 A schematic structural diagram of a composite current collector interface bonding force testing device provided in a specific embodiment of the present invention.

[0065] Figure 2 A schematic structural diagram of a fixing tool provided for a specific embodiment of the present invention.

[0066] Figure 3 A side view of a fixing tool provided in accordance with a specific embodiment of the present invention.

[0067] Figure 4 A schematic diagram of a slide rail on the surface of a first supporting beam provided for a specific embodiment of the present invention.

[0068] Figure 5 A schematic structural diagram of a limiting portion provided for a specific embodiment of the present invention.

[0069] Figure 6 A schematic structural diagram of a first supporting beam and a second supporting beam provided for a specific embodiment of the present invention.

[0070] Figure 7 A schematic structural diagram of a position limiting portion with different detection areas provided in a specific embodiment of the present invention.

[0071] Figure 8 A schematic structural diagram of a position limiting portion with different detection areas provided in a specific embodiment of the present invention.

[0072] Fig. 9 A schematic structural diagram of a drawing tool provided in a specific embodiment of the present invention.

[0073] Fig.10 A schematic structural diagram of a drawing tool provided in a specific embodiment of the present invention.

[0074] Fig.11 A schematic diagram of measuring the pull-out force using an automatic pull-out test device provided in accordance with a specific embodiment of the present invention.

[0075] Fig.12 A schematic diagram of measuring the pull-out force using a pull-out test device or a tensile testing machine is provided for a specific embodiment of the present invention.

[0076] Fig.13 A schematic structural diagram of a curing plate provided in a specific embodiment of the present invention.

[0077] Fig.14 This is a flow chart for testing the interfacial bonding strength of the composite current collector provided in Example 1.

[0078] Fig.15 This is a schematic diagram of the structure of the detection area provided in Example 1.

[0079] Fig.16 This is a schematic diagram of the structure of the detection area provided in Example 2.

[0080] Among them, 1-test platform; 2-test sample; 3-fixed tooling; 31-first supporting beam; 32-limiting part; 33-second supporting beam; 312-slide rail; 321-slider; 4-pulling tooling; 41-first end; 42-connecting part; 43-second end; 5-curing plate; 51-accommodating area. DETAILED DESCRIPTION

[0081] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0082] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0083] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0084] In a specific embodiment, the present invention provides a composite current collector interface bonding force testing device, such as Figure 1 As shown, it includes a test platform 1, a fixing tool 3, a drawing tool 4 and a curing plate 5. The surface of the test platform 1 is paved with a sample 2 to be tested, which is used to support the sample 2 to be tested. The fixing tool 3 includes a first supporting beam 31, a second supporting beam 33 and a plurality of limiting parts 32. The first supporting beam 31 and the second supporting beam 33 are arranged side by side on the sample 2 to be tested, and are independently and detachably connected to the test platform 1, which is used to fix the sample 2 to be tested. The two ends of the limiting part 32 are respectively and movably connected to the first supporting beam 31 and the second supporting beam 33. The limiting part 32 is provided with a detection area or two adjacent limiting parts 32 are spliced ​​to form a detection area. The drawing tool 4 is located in the detection area and is connected to the sample 2 to be tested. The curing plate 5 is stacked with the test platform 1, which is used to clamp and cure the drawing tool 4. When in use, after removing the curing plate 5, the drawing tool 4 is pulled out to test the interface bonding force.

[0085] In some embodiments, the sample 2 to be tested may be a composite film composed of various base films and coatings, including but not limited to composite current collectors, conventional current collectors, diaphragms, adhesive films, multilayer metal or non-metal films, etc. The testing device provided by the present invention can test the bonding force between a base film and a coating or between different coatings.

[0086] In some embodiments, the size of the test platform 1 is customized according to the size and quantity of the sample 2 to be tested. The test platform 1 is made of materials with high mechanical strength, including but not limited to aluminum or aluminum alloy, copper or copper alloy, stainless steel, etc. The thickness of the test platform 1 is 3 to 8 mm. The surface of the test platform 1 is provided with a pre-bonding layer for preliminary fixation of the sample 2 to be tested. During the application process, after cutting the sample 2 to be tested and determining the test site and size, the sample 2 to be tested is laid flat on the test platform 1, and then bonded and fixed using the pre-bonding layer. Specifically, the pre-bonding layer includes a plurality of bonding portions, and the plurality of bonding portions are evenly distributed on one side surface of the test platform 1 on which the sample 2 to be tested is laid, and at least part of the bonding portions are spaced apart at the edge of the test platform 1 to ensure that the sample 2 to be tested is flat. The number and position of the bonding parts are adjusted according to the shape and size of the actual sample 2 to be tested. For example, when the sample 2 to be tested is rectangular as a whole, four bonding parts are set at four corners of the customized test platform 1; when the sample 2 to be tested is circular as a whole, four bonding parts are set at four symmetrical points along the circumference of the customized test platform 1. The bonding parts can be double-sided adhesive tapes well known to those skilled in the art.

[0087] In some embodiments, Figure 2 As shown, the fixing fixture 3 is formed by assembling the first supporting beam 31, the second supporting beam 33 and a plurality of limiting parts 32, and the two ends of the limiting parts 32 are connected to the first supporting beam 31 and the second supporting beam 33 by sliding connection, rivet connection, slot connection, bolt connection or interference connection, or a combination of at least two of them. Preferably, a slide rail type is adopted, specifically, as Figure 3 , Figure 4 and Figure 5 As shown, a slide rail 312 is independently provided on the surface of one side where the first supporting beam 31 and the second supporting beam 33 are close to each other, and sliders 321 are independently provided at both ends of the limiting portion 32. The sliders 321 are movably connected to the slide rail 312. During application, the distance between two adjacent limiting portions 32 is adjusted by sliding the limiting portion 32 to obtain a detection area of ​​a desired size.

[0088] In addition, the material of the fixing fixture 3 includes any one of stainless steel, ceramics, plastics and wood, or a combination of at least two of them. And the thickness of the main structure of the fixing fixture 3 is the same, that is, the main body thickness of the first supporting beam 31, the second supporting beam 33 and the limiting portion 32 is the same, specifically 1 to 5 mm, preferably 2 to 4 mm. At the same time, the first supporting beam 31, the second supporting beam 33 and the limiting portion 32 are independently provided with limiting gaskets on the surface of one side close to the sample to be tested 2, which are used to fix the sample to be tested 2 to prevent the sample from slipping during the pulling process. The specific thickness of the limiting gasket is 0.5 to 2 mm, preferably 0.5 to 1 mm. The limiting gasket can be made of elastic rubber resin materials commonly used in the field, including but not limited to fluororubber, nitrile rubber and silicone rubber, to prevent damage to the sample to be tested 2.

[0089] In the present invention, the first supporting beam 31 and the second supporting beam 33 are independently connected to the test platform 1 by snap connection, rivet connection or bolt connection, and the spacing between the first supporting beam 31 and the second supporting beam 33 can be adjusted according to the size of different test areas. The total area covered by the first supporting beam 31 and the second supporting beam 33 is 6% to 30% of the area of ​​the sample 2 to be tested. Figure 6As shown, the first supporting beam 31 and the second supporting beam 33 are both rectangular parallelepiped structures, and are arranged side by side along the length direction or width direction of the sample 2 to be tested, preferably extending along the length direction of the sample 2 to be tested, so as to be fixed by both sides of the sample 2 to be tested. The widths of the first supporting beam 31 and the second supporting beam 33 are independently 2 to 10 mm, preferably 4 to 6 mm. The lengths of the first supporting beam 31 and the second supporting beam 33 are customized according to the total length of the sample 2 to be tested.

[0090] Furthermore, the first supporting beam 31 and the second supporting beam 33 are spliced ​​structures or telescopic structures, so that the lengths of the first supporting beam 31 and the second supporting beam 33 can be adjusted according to different test requirements and sample sizes. When the first supporting beam 31 and the second supporting beam 33 are spliced ​​structures, they are specifically composed of a plurality of independent splicing blocks connected in series in sequence, and are connected in a detachable connection method commonly used by technicians in the field. The splicing blocks can be increased or decreased according to different test requirements to ensure that the lengths of the first supporting beam 31 and the second supporting beam 33 are equal. When the first supporting beam 31 and the second supporting beam 33 are telescopic structures, they can be mechanical telescopic, hydraulic telescopic or compound telescopic, and can be adjusted according to actual conditions in the field.

[0091] The number, shape and size of the limiter 32 in the present invention are adapted to the number, shape and size of the specified or selected test samples to obtain a detection area that meets the test requirements. The shape of the detection area can be any one of polygonal, circular, semicircular or elliptical, or a combination of at least two of them.

[0092] For example, Figure 7 and Figure 8As shown, if the selected test sample is square, that is, the detection area needs to be square, a square detection area that meets the size requirements can be directly opened on the same limiting portion 32, or two limiting portions 32 with rectangular grooves can be spliced ​​to form a square detection area that meets the size requirements. If the selected test sample is circular, that is, the detection area needs to be circular, a circular detection area that meets the size requirements can be directly opened on the same limiting portion 32, or two limiting portions 32 with semicircular grooves can be spliced ​​to form a circular detection area that meets the size requirements. If the selected test sample contains both square and circular, that is, the detection area needs to contain both square and circular, any one or more limiting portions 32 can be selected to directly open a square detection area and / or a circular detection area that meets the size requirements, or any one or more limiting portions 32 can be selected to independently open corresponding grooves, so that two adjacent limiting grooves can be spliced ​​to form a square detection area and / or a circular detection area that meets the size requirements. If multiple test samples of different sizes are required for testing, the overall symmetry of the test positions must be ensured to prevent uneven force on the samples during curing.

[0093] Specifically, the limiting portion 32 may be a rectangular parallelepiped structure, the length of which is adjusted according to the size of the test sample, and the width of which may be 1 to 5 mm, preferably 2 to 4 mm. In addition, the limiting portion 32 may be a splicing structure or a telescopic structure, so that the length of the limiting portion 32 may be adjusted according to different test requirements and the size of the test sample. When the limiting portion 32 is a splicing structure, it is specifically composed of a plurality of independent splicing blocks connected in series in sequence, and is connected using a detachable connection method commonly used by those skilled in the art, and the splicing blocks may be increased or decreased according to different test requirements. When the limiting portion 32 is a telescopic structure, it may be a mechanical telescopic structure, a hydraulic telescopic structure, or a compound telescopic structure, and the art may make adjustments according to actual conditions.

[0094] In some embodiments, Fig. 9 and Fig.10 As shown, the drawing tool 4 includes a first end 41, a connecting portion 42 and a second end 43 connected in sequence along the axial direction, and the second end 43 is at least partially located inside the detection area along the axial direction and connected to the sample to be tested 2. Specifically, the surface of the second end 43 close to the side of the sample to be tested 2 is provided with a curing adhesive layer for bonding the sample to be tested 2, and is specifically made of a room temperature fast curing type adhesive. The present invention does not specifically limit the material of the drawing tool 4, including but not limited to any one of stainless steel, ceramics, plastics and wood or a combination of at least two of them, preferably stainless steel.

[0095] like Figure 1As shown, the maximum linear length d3 of the orthographic projection of the first end 41 in the detection area is smaller than the maximum linear length d2 of the orthographic projection of the second end 43 in the detection area, that is, the drawing tool 4 is a structure with a small upper end and a large lower end. The maximum linear length d1 of the detection area is greater than the maximum linear length d2 of the orthographic projection of the second end 43 in the detection area, so that after the second end 43 is placed in the detection area, the distance between the outer edge of the second end 43 and the edge of the detection area is 2 to 5 mm. Furthermore, the maximum linear length of the orthographic projection of the second end 43 in the detection area is 5 to 50 mm, preferably 10 to 30 mm. The present invention does not specifically limit the shape of the first end 41 and the second end 43, which can be circular or rectangular, and is specifically adjusted according to the shape of the detection area. And the shapes of the first end 41 and the second end 43 can be the same or different. When the first end 41 and the second end 43 are circular in shape, the maximum linear length refers to the diameter length of the first end 41 or the second end 43; when the first end 41 and the second end 43 are rectangular in shape, the maximum linear length refers to the long side length of the first end 41 or the second end 43.

[0096] The connecting portion 42 is used as an intermediate transition zone for the drawing tool 4 to fix the drawing head for drawing test. It has an upper end face and a lower end face. The upper end face is connected to the first end 41, and there is a gap between the outer edge of the upper end face and the outer edge of the first end 41, specifically 1 to 10 mm; the lower end face is connected to the second end 43, and the outer edge of the lower end face is flush with the outer edge of the second end 43. Further, the connecting portion 42 is a necking transition (such as Fig. 9 As shown), smooth transition of inclined surface (as shown Fig.10 The height of the connecting portion 42 is 10 to 50 mm, preferably 20 to 30 mm.

[0097] In addition, the pulling force of the pulling test is different according to the size of the pulling tool 4. Specifically, when the maximum linear length of the positive projection of the second end 43 in the test area is 5 to 20 mm, the pulling force is ≤ 20 N, and the following can be used: Fig.11 The automatic pull-out test device shown in the figure measures the pull-out force; when the maximum linear length of the positive projection of the second end 43 in the test area is 20 to 50 mm, excluding 20 mm, the pull-out force is greater than 20 N, and the pull-out force can be measured using the following method: Fig.12 The test is performed using the pull-out test equipment or tensile testing machine shown in the figure. Since the test platform 1 is prone to positional changes during the test, it is necessary to use a fixture to fix the four corners of the test platform 1 on the workbench before testing.

[0098] In some embodiments, Figure 1 and Fig.13 As shown, the size of the curing plate 5 matches the size of the test platform 1, and the outer edge of the curing plate 5 is flush with the outer edge of the test platform 1. In addition, a plurality of accommodation areas 51 are provided on the surface of the curing plate 5, and the accommodation areas 51 correspond to and are coaxial with the detection area. The maximum linear length d3 of the orthographic projection of the first end 41 in the detection area is less than the maximum linear length d4 of the accommodation area 51 and less than the maximum linear length d2 of the orthographic projection of the second end 43 in the detection area, so that the accommodation area 51 is engaged with the second end 43 of the drawing tool 4 to perform the clamping and curing of the drawing tool 4.

[0099] In another specific embodiment, the present invention provides a composite current collector interface bonding force testing method, the testing method uses a composite current collector interface bonding force testing device according to a specific embodiment, and the testing method includes:

[0100] S1: Determine the test requirements and select the test platform 1, the fixing fixture 3, the drawing fixture 4 and the curing plate 5.

[0101] Specifically, the test requirements include: (1) Testing the uniformity of the binding force of different regions of the test sample 2: dividing the entire test sample 2 into multiple regions to detect the binding force of the test sample in the corresponding region and analyze its uniformity. (2) Testing the binding force of a specified region of the test sample 2: selecting any one or more specified regions from the entire test sample 2 to respectively detect the binding force of the test sample in the corresponding region.

[0102] The selection of the test platform 1 includes: customizing the material of the test platform 1 and the dimensional parameters such as length, width and thickness according to the test requirements of the sample 2 to be tested.

[0103] Selecting the fixing tool 3 includes: customizing the material, quantity, shape, connection method, and dimensional parameters such as length, width and thickness of the first supporting beam 31, the second supporting beam 33 and the limiting portion 32 according to the test requirements of the sample 2 to be tested.

[0104] Selecting the drawing tool 4 includes: customizing the material, shape, and dimensional parameters such as the maximum linear length, height, and thickness of the first end 41 , the connecting portion 42 , and the second end 43 according to the test requirements of the sample 2 to be tested.

[0105] Selecting the curing plate 5 includes: customizing the size of the curing plate 5 , the number, shape and size parameters of the accommodating areas 51 according to the test requirements of the sample 2 to be tested.

[0106] S2: Lay the sample 2 to be tested on the surface of the test platform 1, and fix the sample 2 to be tested on the test platform 1 using a fixing tool 3 to form a detection area that meets the test requirements.

[0107] Specifically, after laying the sample 2 to be tested on the test platform 1, determine the position and size of the test area, and use the pre-bonding layer to preliminarily fix the sample 2 to be tested; then use the first supporting beam 31 and the second supporting beam 33 to further assemble and fix the sample 2 to the test platform 1; then adjust the position of each limit part 32 according to the position, shape and size of the test sample to form a detection area that meets the test size and shape.

[0108] S3: Then, assemble the drawing tool 4 and fix the drawing tool 4 on the sample 2 to be tested in the testing area.

[0109] Specifically, the second end 43 of the pulling tool 4 is bonded and fixed to the surface of the sample 2 to be tested in the detection area using a composite adhesive after degassing. The bonding effectiveness can be improved by degassing the two-component composite adhesive. The composite adhesive is a mixture of a main adhesive and a curing agent. Furthermore, the main adhesive includes any one of epoxy adhesives, phenolic adhesives, acrylate adhesives or polyurethane adhesives, or a combination of at least two; the curing agent includes any one of aliphatic polyamines, polyamides, tertiary amines and polythiols, or a combination of at least two.

[0110] S4: The drawing tool 4 is clamped and cured using a curing plate 5, and then the curing plate 5 is removed to perform a drawing force test.

[0111] Specifically, the curing plate 5 is aligned with the test platform 1 and passed through the drawing fixture 4 for one-time fixation. The drawing fixture 4 is clamped and cured at a constant pressure for 6 to 15 minutes at room temperature by the weight of the curing plate 5. The pressure of the clamping and curing is 0.05 to 0.3 MPa.

[0112] In some embodiments, the pull-out force test uses a pull-out device. The present invention selects different pull-out devices according to the pull-out force of the pull-out test. Specifically, when the pull-out force required for the test is ≤20N, the following can be used: Fig.11 The automatic pull-out test equipment shown in the figure measures the pull-out force. When the pull-out force required for the test is greater than 20N, the following can be used: Fig.12 The pull-out test equipment or tensile machine equipment shown in the figure is used for testing. In actual application, first use the automatic pull-out equipment to test the pull-out force (the maximum testable range must be >20N) to perform a pull-out test on any test sample, and the upward operation is 3mm / min. If the pull-out fixture 4 is successfully pulled out and the pull-out force reading is <20N, then the remaining test samples are pulled out in turn. If the pull-out fixture 4 cannot be pulled out, use the pull-out test equipment or tensile machine equipment for testing. Before the test, fix the test platform 1 on the equipment workbench, and then perform a pull-out test on each test sample in turn.

[0113] In some embodiments, the test method further includes: determining whether the pull-out test result is a valid pull-out. If it is determined to be a valid pull-out, the test is terminated. Otherwise, adjustments are made after clarifying the cause of the ineffective pull-out, and then the test is repeated.

[0114] Specifically, the determination method includes: (1) qualitative: it can be seen with the naked eye that the coating of the test sample is completely detached from the sample to be tested 2, and there is basically no coating left on the surface of the base film; (2) quantitative: after the drawing is completed, the surface resistance value of the test sample is measured using a resistance meter or the surface morphology of the sample is observed using a microscope.

[0115] The ineffective pulling conditions include: (1) the coating is not substantially separated from the sample; (2) the cured adhesive layer is separated from the lower surface of the second end portion 43 of the pulling tool 4;

[0116] Cause investigation: (1) The bonding strength of the adhesive in the cured bonding layer is less than the bonding strength between the base film and the coating, so replace it with an adhesive with greater bonding strength and continue the test; (2) The lower surface roughness of the second end 43 of the pulling tool 4 is too low, and it needs to be properly polished to increase the roughness before continuing the test.

[0117] Example 1

[0118] In this embodiment, the interfacial bonding force of the composite current collector is tested to compare the uniformity of the bonding force in different regions of the composite material. Fig.14 As shown, the specific steps include:

[0119] (1) Customize a 100 mm × 100 mm × 5 mm stainless steel test platform 1, cut a 100 mm × 100 mm sample 2, and spread it flat on the test platform 1. Determine the position and size of the test area, and stick double-sided tape on the four corners of the test platform 1 to form a pre-bonding layer to preliminarily fix the sample 2.

[0120] (2) Customized fixture 3, the main body of which is made of stainless steel with a thickness of 2 mm. The fixture 3 includes a first supporting beam 31, a second supporting beam 33 and twelve limiting parts 32. The first supporting beam 31 and the second supporting beam 33 are both rectangular structures with a width of 5 mm. The first supporting beam 31 and the second supporting beam 33 are arranged side by side on the sample 2 to be tested along the length direction of the sample 2 to be tested, and are independently snap-connected to the test platform 1. The two ends of each limiting part 32 are slidably connected to the first supporting beam 31 and the second supporting beam 33. Fig.15As shown, the limiting part 32 is a rectangular flat plate structure, and a semicircular groove is provided on the surface of each limiting part 32. Two limiting parts 32 are spliced ​​to form a cube with a side length of 30 mm, and there are six circular detection areas inside, and the diameter d1 of the detection area is 24 mm, and they are sequentially numbered 1 to 6. And the first supporting beam 31, the second supporting beam 33 and the limiting part 32 are all provided with a limiting gasket made of elastic rubber material with a thickness of 1 mm on the surface of the side close to the sample 2 to further fix the sample 2 to be tested.

[0121] (3) Six identical stainless steel drawing tools 4 are customized according to the inspection area. The drawing tool 4 includes a first end 41, a connecting part 42 and a second end 43 connected in sequence along the axial direction. The first end 41 is circular with a diameter d3 of 16 mm; the second end 43 is circular with a diameter d2 of 120 mm; the connecting part 42 is a necked transition with a height of 20 mm. The connecting part 42 has an upper end face and a lower end face, the upper end face is connected to the first end 41, and a gap of 3 mm is left between the outer edge of the upper end face and the outer edge of the first end 41, and the lower end face is connected to the second end 43, and the outer edge of the lower end face is flush with the outer edge of the second end 43.

[0122] (4) Mix the epoxy resin main binder and the curing agent in a certain proportion and stir evenly, use a centrifuge to degas, take an appropriate amount and evenly apply it on the lower surface of the second end face of the drawing tool 4, and bond and fix it on the sample 2 to be tested in the corresponding test area.

[0123] (5) A 100mm×100mm×5mm stainless steel curing plate 5 is customized, and six circular storage areas 51 with a diameter d4 of 18mm are opened on its surface, so that the positions of the storage areas 51 correspond to the positions of the detection areas one by one and are coaxial. The curing plate 5 is placed flush with the test platform 1 and passed through the drawing fixture 4. The second end 43 of the drawing fixture 4 is cured at a constant pressure of 0.05MPa for 10 minutes at room temperature by relying on the weight of the curing plate 5, and then the curing plate 5 is removed.

[0124] (6) Use an automatic pull-out tester to test the pull-out force (the maximum test range must be greater than 20N) and perform a pull-out test on the internal test sample in the No. 1 test area. The upward operation is 3mm / min. If the pull-out head is successfully pulled out and the pull-out force reading is less than 20N, then perform pull-out tests on the internal test samples in the No. 2 to No. 6 test areas in turn. If the pull-out head cannot be pulled out, use a pull-out tester or a tensile machine for testing. Before the test, fix the test platform 1 on the equipment platform, and then perform pull-out tests on the test samples in the No. 1 to No. 6 test areas in turn.

[0125] (7) Determine whether the pull-out test result is an effective pull-out. The determination method includes: ① Qualitative: It can be seen with the naked eye that the coating of the test sample is completely detached from the sample to be tested 2, and there is basically no coating left on the surface of the base film; ② Quantitative: After the pull-out is completed, use a resistance meter to measure the surface resistance value of the test sample or use a microscope to observe the surface morphology of the sample. When it is determined to be an effective pull-out, the test is terminated. Otherwise, the reason for the ineffective pull-out is clarified and adjustments are made before retesting. Among them, the adjustment method for ineffective pull-out includes: ① If the bonding strength of the adhesive of the cured bonding layer is less than the bonding force between the base film and the coating, it is necessary to replace the adhesive with a stronger bonding strength before continuing the test; ② The lower surface roughness of the second end 43 of the pulling tool 4 is too low, and it is necessary to grind it appropriately to increase the roughness before continuing the test.

[0126] Example 2

[0127] This embodiment tests the interfacial bonding strength of the composite current collector to evaluate the bonding strength of a specified area (different test sizes and shapes) of the composite material, specifically comprising the following steps:

[0128] (1) Customize a 100 mm × 100 mm × 6 mm stainless steel test platform 1, cut a 100 mm × 100 mm sample 2 to be tested, and spread it flat on the test platform 1. Determine the position and size of the test area, and stick double-sided tape on the four corners of the test platform 1 to form a pre-bonding layer to preliminarily fix the sample 2 to be tested.

[0129] (2) Customized fixing fixture 3, the main body of which is made of stainless steel with a thickness of 3 mm. The fixing fixture 3 includes a first supporting beam 31, a second supporting beam 33 and twelve limiting parts 32. The first supporting beam 31 and the second supporting beam 33 are both rectangular structures with a width of 5 mm. The first supporting beam 31 and the second supporting beam 33 are arranged side by side on the sample 2 to be tested along the length direction of the sample 2 to be tested, and are independently snap-connected to the test platform 1. The two ends of each limiting part 32 are slidably connected to the first supporting beam 31 and the second supporting beam 33 respectively. Eight limiting parts 32 are provided with semicircular grooves, and four limiting parts 32 are provided with rectangular grooves. The limiting parts 32 are spliced ​​in pairs to form a Fig.16 The six detection areas shown include two square detection areas and four circular detection areas, where each square detection area has two circular detection areas on both sides, the side length of the square detection area is 20 mm, and the diameter of the circular detection area is 24 mm. The first supporting beam 31, the second supporting beam 33 and the limiting portion 32 are all provided with a limiting gasket made of elastic rubber material with a thickness of 1.2 mm on the surface of the side close to the sample 2 to be tested, so as to further fix the sample 2 to be tested.

[0130] (3) Six stainless steel drawing tools 4 were customized according to the detection area. The drawing tool 4 includes a first end 41, a connecting part 42 and a second end 43 connected in sequence along the axial direction. The first end 41 and the second end 43 of two of the drawing tools 4 are square, the side length of the first end 41 is 12 mm, the side length of the second end 43 is 16 mm, the connecting part 42 is a bevel smooth transition, and the height is 20 mm. The first end 41 and the second end 43 of the other four drawing tools 4 are circular, the diameter of the first end 41 is 16 mm, the diameter of the second end 43 is 20 mm, the connecting part 42 is a necking transition, and the height is 20 mm. The connecting part 42 has an upper end face and a lower end face, the upper end face is connected to the first end 41, and a gap of 2 mm is left between the outer edge of the upper end face and the outer edge of the first end 41, and the lower end face is connected to the second end 43, and the outer edge of the lower end face is flush with the outer edge of the second end 43.

[0131] (4) Mix the epoxy resin main binder and the curing agent in a certain proportion and stir evenly, use a centrifuge to degas, take an appropriate amount and evenly apply it on the lower surface of the second end face of the drawing tool 4, and bond and fix it on the sample 2 to be tested in the corresponding test area.

[0132] (5) A 100 mm × 100 mm × 5 mm stainless steel curing plate 5 is customized, and six receiving areas 51 are opened on its surface, of which two receiving areas 51 are square and the other four receiving areas 51 are circular, so that the positions of the receiving areas 51 correspond to the positions of the detection areas one by one and are coaxial. The curing plate 5 is placed flush with the test platform 1 and passed through the drawing fixture 4. The second end 43 of the drawing fixture 4 is cured at a constant pressure of 0.1 MPa for 12 minutes at room temperature by the weight of the curing plate 5, and then the curing plate 5 is removed.

[0133] (6) Use an automatic pull-out tester to test the pull-out force (the maximum test range must be greater than 20N) and perform a pull-out test on the internal test sample in the No. 1 test area. The upward operation is 3mm / min. If the pull-out head is successfully pulled out and the pull-out force reading is less than 20N, then perform pull-out tests on the internal test samples in the No. 2 to No. 6 test areas in turn. If the pull-out head cannot be pulled out, use a pull-out tester or a tensile machine for testing. Before the test, fix the test platform 1 on the equipment platform, and then perform pull-out tests on the test samples in the No. 1 to No. 6 test areas in turn.

[0134] (7) Determine whether the pull-out test result is an effective pull-out. The determination method includes: ① Qualitative: It can be seen with the naked eye that the coating of the test sample is completely detached from the sample to be tested 2, and there is basically no coating left on the surface of the base film; ② Quantitative: After the pull-out is completed, use a resistance meter to measure the surface resistance value of the test sample or use a microscope to observe the surface morphology of the sample. When it is determined to be an effective pull-out, the test is terminated. Otherwise, the reason for the ineffective pull-out is clarified and adjustments are made before retesting. Among them, the adjustment method for ineffective pull-out includes: ① If the bonding strength of the adhesive of the cured bonding layer is less than the bonding force between the base film and the coating, it is necessary to replace the adhesive with a stronger bonding strength before continuing the test; ② The lower surface roughness of the second end 43 of the pulling tool 4 is too low, and it is necessary to grind it appropriately to increase the roughness before continuing the test.

[0135] The present invention can change the shape and size of the test sample according to demand, minimize the sample test size, and can select the area to test the bonding force. At the same time, multiple samples can be cured and tested together to improve the test efficiency. During the application process, a combination of fixed shape + elastic rubber limit gasket is adopted to effectively fix the sample 2 to be tested, and the deformation around the sample can be controlled or homogenized to a certain extent. In addition, the present invention can adjust the test area size of the fixed tool 3 and change the size of the drawing tool 4. The relationship between the sample deformation amount and the interface bonding force can be studied within a certain range, and it has high flexibility.

[0136] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A composite current collector interface bonding strength testing device, characterized in that: It includes a test platform, a fixing tool, a drawing tool and a curing plate; the surface of the test platform is paved with a sample to be tested; the fixing tool includes a first supporting beam, a second supporting beam and a plurality of limiting parts, the first supporting beam and the second supporting beam are arranged side by side on the sample to be tested, and are independently and detachably connected to the test platform for fixing the sample to be tested, the two ends of the limiting part are movably connected to the first supporting beam and the second supporting beam respectively, and a detection area is opened on the limiting part or two adjacent limiting parts are spliced ​​to form a detection area; the drawing tool is located in the detection area and is connected to the sample to be tested; the curing plate and the test platform are stacked and arranged for clamping and curing the drawing tool.

2. The composite current collector interface bonding force testing device according to claim 1, characterized in that: The surface of the test platform is provided with a pre-bonding layer; Preferably, the pre-bonding layer includes a plurality of bonding parts, and the plurality of bonding parts are evenly distributed on a surface of one side of the test platform on which the sample to be tested is laid; Preferably, at least part of the bonding portions are arranged at intervals on the edge of the test platform; Preferably, the test platform is connected by snap-fitting, riveting or bolting the first supporting beam and the second supporting beam respectively.

3. The composite current collector interface bonding force testing device according to claim 1, characterized in that: The detection area is in any one of polygonal, circular, semicircular or elliptical shapes or a combination of at least two of them; Preferably, the first supporting beam, the second supporting beam and the limiting portion are independently spliced ​​structures or telescopic structures; Preferably, both ends of the limiting portion are connected to the first supporting beam and the second supporting beam by any one of sliding connection, rivet connection, slot connection, bolt connection or interference connection or a combination of at least two of them; Preferably, a slide rail is independently provided on the surface of one side of the first supporting crossbeam and the second supporting crossbeam close to each other, and sliders are independently provided at both ends of the limiting portion, and the sliders are movably connected to the slide rail; Preferably, the first supporting crossbeam, the second supporting crossbeam and a surface of the limiting portion on one side close to the sample to be tested are independently provided with limiting gaskets; Preferably, the first supporting beam and the second supporting beam are independently rectangular parallelepiped structures.

4. The composite current collector interface bonding force testing device according to claim 3, characterized in that: The first supporting beam, the second supporting beam and the limiting portion have the same thickness; Preferably, the thickness of the first supporting beam, the second supporting beam and the limiting portion are independently 1 to 5 mm; Preferably, the total area of ​​the sample to be tested covered by the first supporting beam and the second supporting beam is 6% to 30% of the area of ​​the sample to be tested; Preferably, the width of the first supporting beam and the second supporting beam are independently 2 to 10 mm; Preferably, the limiting gasket has a thickness of 0.5 to 2 mm; Preferably, the material of the fixing tool includes any one of stainless steel, ceramic, plastic and wood, or a combination of at least two of them.

5. The composite current collector interface bonding force testing device according to any one of claims 1 to 4, characterized in that: The drawing tool comprises a first end, a connecting portion and a second end connected in sequence along the axial direction, wherein the second end is at least partially located inside the detection area along the axial direction and connected to the sample to be tested; Preferably, the maximum linear length of the orthographic projection of the first end in the detection area is smaller than the maximum linear length of the orthographic projection of the second end in the detection area; Preferably, the connecting portion has an upper end surface and a lower end surface, the upper end surface and the lower end surface are respectively connected to the first end portion and the second end portion, a gap is left between the outer edge of the upper end surface and the outer edge of the first end portion, and the outer edge of the lower end surface is flush with the outer edge of the second end portion; Preferably, the connecting portion is in the form of a necked transition, an inclined smooth transition or a curved smooth transition; Preferably, a cured adhesive layer is provided on a surface of the second end portion close to the sample to be tested.

6. The composite current collector interface bonding force testing device according to claim 5, characterized in that: After the second end is placed in the detection area, the distance between the outer edge of the second end and the edge of the detection area is 2 to 5 mm; Preferably, the maximum linear length of the orthographic projection of the second end in the detection area is 5 to 50 mm; Preferably, the height of the connecting portion is 10 to 50 mm; Preferably, the length of the gap between the outer edge of the upper end surface of the connecting portion and the outer edge of the first end portion is 1 to 10 mm; Preferably, the material of the drawing tool includes any one of stainless steel, ceramic, plastic and wood, or a combination of at least two of them.

7. The composite current collector interface bonding force testing device according to claim 5 or 6, characterized in that: The curing plate surface is provided with a plurality of accommodating areas, the accommodating areas corresponding to the detection areas, so that the accommodating areas are engaged with the second end of the drawing tool; Preferably, the outer edge of the curing plate is flush with the outer edge of the testing platform; Preferably, the maximum linear length of the orthographic projection of the first end in the detection area is less than the maximum linear length of the accommodating area and less than the maximum linear length of the orthographic projection of the second end in the detection area.

8. A method for testing the interfacial bonding strength of a composite current collector, characterized in that: The test method adopts the composite current collector interface bonding force test device according to any one of claims 1 to 7, and the test method comprises: (1) Determine the test requirements and select the test platform, fixture, drawing fixture and curing plate; (2) Laying the sample to be tested on the surface of the test platform, fixing the sample to be tested on the test platform using a fixing tool, and forming a test area that meets the test requirements; (3) then assembling the drawing tool and fixing the drawing tool on the sample to be tested in the testing area; (4) Use a curing plate to fix the pulling tool in place and then remove the curing plate to perform a pulling force test.

9. The method for testing the interfacial bonding strength of a composite current collector according to claim 8, characterized in that: The test requirements include: testing the uniformity of the binding force of different regions of the sample to be tested or testing the binding force of a specified region of the sample to be tested; Preferably, the testing method comprises: using a degassing treated composite adhesive to bond and fix the drawing tool to the surface of the sample to be tested in the testing area; Preferably, the composite binder comprises a mixture of a main binder and a curing agent; Preferably, the main adhesive comprises any one of epoxy adhesive, phenolic adhesive, acrylate adhesive or polyurethane adhesive, or a combination of at least two thereof; Preferably, the curing agent comprises any one or a combination of at least two of aliphatic polyamines, polyamides, tertiary amines and polythiol; Preferably, the time for the said carding and curing is 6 to 15 minutes; Preferably, the pressure of the locking and curing is 0.05-0.3 MPa.

10. The method for testing the interfacial bonding strength of a composite current collector according to claim 8 or 9, characterized in that: The pull-out force test uses a tensile device; Preferably, the test method further comprises: determining whether the pull-out test result is a valid pull-out, and when it is determined to be a valid pull-out, terminating the test; otherwise, making adjustments after clarifying the cause of the ineffective pull-out, and then retesting.

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