CN111175327A - Method for detecting bonding effect between lithium ion battery electrode and electronic current collector - Google Patents
Method for detecting bonding effect between lithium ion battery electrode and electronic current collector Download PDFInfo
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- CN111175327A CN111175327A CN201911421110.4A CN201911421110A CN111175327A CN 111175327 A CN111175327 A CN 111175327A CN 201911421110 A CN201911421110 A CN 201911421110A CN 111175327 A CN111175327 A CN 111175327A
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- current collector
- adhesive tape
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- 238000000034 method Methods 0.000 title claims abstract description 29
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 21
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 20
- 230000000694 effects Effects 0.000 title claims abstract description 19
- 239000002390 adhesive tape Substances 0.000 claims abstract description 61
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- 238000001035 drying Methods 0.000 description 5
- 229920003048 styrene butadiene rubber Polymers 0.000 description 5
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 4
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- 239000006257 cathode slurry Substances 0.000 description 4
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- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
- KFDQGLPGKXUTMZ-UHFFFAOYSA-N [Mn].[Co].[Ni] Chemical compound [Mn].[Co].[Ni] KFDQGLPGKXUTMZ-UHFFFAOYSA-N 0.000 description 3
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- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
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- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 2
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- 239000010949 copper Substances 0.000 description 1
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 1
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 1
- 150000002642 lithium compounds Chemical class 0.000 description 1
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
- G01N23/203—Measuring back scattering
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
- G01N23/20008—Constructional details of analysers, e.g. characterised by X-ray source, detector or optical system; Accessories therefor; Preparing specimens therefor
- G01N23/2005—Preparation of powder samples therefor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2223/00—Investigating materials by wave or particle radiation
- G01N2223/10—Different kinds of radiation or particles
- G01N2223/102—Different kinds of radiation or particles beta or electrons
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2223/00—Investigating materials by wave or particle radiation
- G01N2223/40—Imaging
- G01N2223/401—Imaging image processing
Abstract
The invention relates to a method for detecting the bonding effect between an electrode and an electronic current collector of a lithium ion battery, which comprises the following steps: cutting the electrode pole piece, and cleaning the floating powder on the surface and the edge of the pole piece to obtain a sample to be detected; covering the adhesive tape on the central position of the surface of the pole piece material area; stripping the adhesive tape in a direction parallel to the pole piece, and naming the current collector stripped of the active substance as a detection sample; sampling on a detection sample, observing by using a scanning electron microscope and taking a picture; after the amplified photos with the same times are taken, the amplified photos are processed by using graphic processing software for identifying and counting the pixel contrast depth of the pictures, and the pixel number ratio of the residual particles of the electrodes with different formulas is obtained. The invention combines the back scattering pattern of the scanning electron microscope after the pole piece is stripped from the substrate with the image processing software, can statistically analyze the size of the binding power between different electrode plates and the conductive current collector substrate, provides prospective reference for selecting the battery electrode formula, and has very high practical value.
Description
Technical Field
The invention relates to a method for detecting the bonding effect between a lithium ion battery electrode and an electronic current collector based on image analysis, belonging to the technical field of lithium ion batteries.
Background
The lithium ion battery generally comprises a positive electrode, a negative electrode, a diaphragm, an electrolyte, a packaging shell and the like, wherein the two most important parts are the positive electrode and the negative electrode respectively, and the positive electrode and the negative electrode are prepared by respectively uniformly mixing an active material, a conductive agent and a binder and then coating the mixture on an electron current collector taking an Al foil and a Cu foil as substrates. The migration of Li ions occurs between the positive and negative electrodes, the separator and the electrolyte, the migration of electrons is transferred to the electron current collector by means of the active material and the conductive agent, and the electron current collector is then transferred to an external circuit to reach the other electrode. Therefore, the electron transfer rate between the active materials of the positive and negative electrodes and the electron current collector largely determines the dynamic performance of the entire battery.
Since the active material expands and contracts in volume during charge and discharge, the following two problems are caused: firstly, the expansion and contraction of the interface between the electrode material and the electron current collector, once the expansion and contraction ratio is too large, the contact between the electrode material and the electron current collector becomes poor, so that the interface contact internal resistance is increased, and the battery performance is reduced; secondly, the overall expansion of the battery is also increased due to the problem that the electrode material is separated from the electron current collector due to expansion and contraction, which leads to deformation of the appearance of the battery and potential safety hazards.
From the above, the bonding effect between the positive and negative electrodes and the electron current collector is very important for the overall performance of the battery. However, at present, studies on the bonding effect between the positive and negative electrodes and the electron current collector are few, and there is no mature effective method for detecting the bonding effect between the positive and negative electrodes and the electron current collector.
Disclosure of Invention
In order to solve the technical problems, the invention provides a method for detecting the bonding effect between a lithium ion battery electrode and an electronic current collector based on image analysis, which has the following specific technical scheme:
the method for detecting the bonding effect between the lithium ion battery electrode and the electronic current collector comprises the following steps:
step 1: preparing a sample: cutting the electrode plate, wherein the material area of the electrode plate faces upwards, cleaning floating powder on the surface and the edge of the electrode plate, and ensuring that no obvious dust and foreign matters exist on the surface of the electrode plate to obtain a sample to be detected;
step 2: preparing an adhesive tape: selecting an adhesive tape, and ensuring that the width of the adhesive tape is smaller than that of the sample to be detected and the length of the adhesive tape is larger than that of the sample to be detected;
and step 3: gluing: covering the adhesive tape on the central position of the surface of the pole piece material area, ensuring that the central line of the adhesive tape in the width direction is superposed with the central line of the pole piece in the width direction, enabling the two ends of the adhesive tape to exceed the corresponding ends of the pole piece, and rolling the surface of the pole piece or the adhesive tape back and forth by using a press roller to enable the adhesive tape to be in close contact with the surface of the pole piece;
and 4, step 4: stripping: respectively clamping a pole piece current collector layer and an adhesive tape layer by using a tensile machine, carrying out 180-degree reverse stretching, attaching active substances to the adhesive tape in a stripping process so as to be separated from the current collector, and naming the current collector stripped of the active substances as a detection sample;
and 5: sampling: sampling at the middle position of a detected sample, observing by using a scanning electron microscope and taking a picture;
step 6: selecting electrodes of the same type but different formulas, and repeating the steps 1-5 to respectively obtain a plurality of groups of photos;
and 7: after the magnified photos with the same times are taken, the magnified photos are processed by graphic processing software which can identify the contrast depth of the pixels of the graphics and count the number of the pixels, and the pixel number ratio of the residual particles of the electrodes with different formulas is obtained.
Further, in the step 5, the sampling position is selected from the position from the stripping start to 1/2-2/3 of the end of the pole piece.
Furthermore, a back scattering mode is required when the current collector is shot by the scanning electron microscope.
The invention has the beneficial effects that:
according to the invention, through combining the back scattering pattern of the scanning electron microscope which is shot on the substrate after the active substance is stripped with the pattern processing software, the size of the adhesive force between different electrode plates and the conductive current collector substrate can be statistically analyzed. The method is simple, has high repeatability and can statistically perform quantitative analysis. Compared with the bonding force tested by a common tensile machine, the bonding effect and the distribution of bonding points can be more truly expressed. For the rolled electrode plate, the traditional tensile machine for testing the bonding force cannot obtain a stable bonding force value between the particles and the conductive current collector substrate, so that the bonding force value cannot be compared; with the method of the present invention, quantitative analysis can be performed by reading the ratio of the number of pixels remaining on the conductive current collector substrate corresponding to the active material particles.
The invention provides guiding significance for the selection of the formula of the pole pieces of the positive and negative poles of the battery, and the service life and the performance stability of the pole pieces of the electrode are determined by testing the bonding effect of the pole pieces at the initial stage of formulation, thereby providing a very valuable reference. Can prevent the performance of the battery from being reduced due to the reduction of the bonding effect in the use process.
Drawings
Figure 1 is a scanning electron microscope backscatter image of sample a of example 1 of the invention,
figure 2 is a scanning electron microscope backscatter image of sample B of example 1 of the invention,
FIG. 3 is a photograph of a sample E' of example 3 of the present invention,
FIG. 4 is a photograph of a sample F' of example 3 of the present invention,
FIG. 5 is a photograph of an electrode sample of sample E peeled off by a tape in example 3 of the present invention,
FIG. 6 is a photograph of an electrode sample F peeled off with tape in example 3 of the present invention.
Detailed Description
The present invention will now be described in further detail with reference to the accompanying drawings.
The method for detecting the bonding effect between the lithium ion battery electrode and the electronic current collector comprises the following steps:
step 1: preparing a sample: firstly, cutting the pole piece into small pieces with the length being more than or equal to 50mm and the width being more than or equal to 35mm by using a paper cutter; the pole piece material area faces upwards, the floating powder on the surface and the edge of the pole piece is cleaned by using a small handheld dust collector, so that no obvious dust or foreign matter is generated on the surface of the pole piece, and a sample to be detected is obtained;
step 2: preparing an adhesive tape: selecting a transparent adhesive tape with the width of 20mm, and ensuring that the width of the adhesive tape is smaller than the width of the sample to be detected and the length of the adhesive tape is larger than the length of the sample to be detected;
and step 3: gluing: covering an adhesive tape on the central position of the surface of a pole piece material area, ensuring that the central line of the adhesive tape in the width direction is superposed with the central line of the pole piece in the width direction, wherein the length of the adhesive tape needs to be about 1-2 cm longer than that of the pole piece, rolling the surface of the pole piece or the adhesive tape back and forth for more than 3 times by using a press roller (2kg) with the diameter of 84mm and the height of 45mm, and keeping the rolling times of each comparison sample consistent so that the adhesive tape is in close contact with the surface;
and 4, step 4: stripping: in order to prevent the abnormity in the stripping process, the pole piece adhesive tape is slightly stripped by 5mm before formal stripping, a tensile machine is utilized to respectively clamp the current collector layer and the adhesive tape at the stripped end, 180-degree reverse stretching is carried out, in the stripping process, active substances are attached to the adhesive tape so as to be separated from the current collector, and the current collector stripped by the active substances is named as a detection sample;
and 5: sampling: sampling is carried out on a detection sample, 1/2-2/3 of the sampling position from the position where stripping starts to the tail end of the pole piece is selected, observation and photographing are carried out by using a scanning electron microscope, a backscattering mode is adopted, the magnification is 200 times, and the resolution is 1600 x 1200.
Since the adhesion force between the electrodes of the same type but different formulations and the conductive current collector substrate is different, in the process of tearing the adhesive tape, generally, the stronger the adhesion force between the active material at the bottom of the electrode and the conductive current collector substrate is, the more the number of particles left on the conductive current collector substrate will be. For commercial materials of lithium ion batteries, the positive electrode typically employs an oxygen-containing lithium compound of a transition metal element, and the conductive current collector substrate is an Al foil; graphite and silicon substances are generally adopted as the negative electrode, and a Cu foil is adopted as a conductive current collector substrate.
the back scattering electron imaging mode is very suitable for observing samples with different element components, and is mainly characterized in that (1) the back scattering electron is a primary electron reflected by the sample, has high energy from 50eV to the energy close to the incident electron, has much stronger penetrating power than the secondary electron, can escape from a deeper region (micron level) in the sample, and has quite wide lateral expansion in the depth range, so that the generated range in the sample is large, and (2) the scattered electron emission coefficient η is increased along with the increase of the atomic number Z, so that the back scattering electron mainly reflects the component characteristics of the sample surface, namely, a part with large average atomic number Z of the sample generates stronger back scattering electron signals, so that a brighter region is formed on a picture, and a part with lower average atomic number generates fewer back scattering electrons, so that a darker region is formed on the picture, so that the back scattering contrast (component contrast) is mainly applied to the observation of different component distribution conditions of the sample surface, such as inorganic mixtures, alloys and the like.
In the positive electrode of the lithium ion battery, the active material is usually a ternary material of lithium cobaltate, lithium manganate, lithium iron phosphate and nickel cobalt manganese, wherein the atomic number of elements such as Co, Ni, Mn, Fe and the like is larger than that of Al element in the current collector substrate, so that the active material is brighter and the substrate is darker in a back scattering mode of a scanning electron microscope; in the negative electrode, the active materials are usually graphite and silicon materials, and the atomic number of the active materials is smaller than that of the Cu element in the current collector substrate, so that the active materials are darker and the substrate is brighter in a back scattering mode of a scanning electron microscope.
Step 6: selecting electrodes of the same type but different formulas, and repeating the steps 1-5 to respectively obtain a plurality of groups of photos of the sample to be detected;
and 7: after the magnified photos with the same times are taken, the magnified photos are processed by graphic processing software which can identify the contrast depth of the pixels of the graphics and count the number of the pixels, and the pixel number ratio of the residual particles of the electrodes with different formulas is obtained. For example, in the comparison of the lithium ion battery cathode system, after the electrodes with different formulas are respectively processed in the same way, the proportion of the number of the finally obtained dark-contrast pixels in the total pixels of the whole picture is sorted, and the highest proportion corresponds to the best bonding effect of the electrode material and the conductive agent fluid.
Example 1
Mixing the lithium ion battery negative active material artificial graphite, a thickener sodium carboxymethyl cellulose (CMCNa) and a binder Styrene Butadiene Rubber (SBR) in a weight ratio of 98.4: 0.8: 0.8, adding a proper amount of deionized water (H)2O), forming stable and uniform fluid with certain viscosity, namely cathode slurry, by a high-speed shearing action with shearing capacity such as a planetary stirrer, a high-speed dispersion disc and the like; and uniformly coating the negative electrode slurry on a copper foil of a negative electrode current collector by using special coating equipment in a certain manner, wherein the thickness of the copper foil is 6 mu m, coating the front surface and the back surface of the copper foil, and drying the coated pole piece to obtain the negative electrode pole piece A.
Mixing the lithium ion battery negative active material artificial graphite, a thickener sodium carboxymethyl cellulose (CMCNa) and a binder Styrene Butadiene Rubber (SBR) in a weight ratio of 98.2: 0.8: 1.0, adding a proper amount of deionized water (H)2O), forming stable and uniform fluid with certain viscosity, namely cathode slurry, by a high-speed shearing action with shearing capacity such as a planetary stirrer, a high-speed dispersion disc and the like; and uniformly coating the negative electrode slurry on a copper foil of a negative electrode current collector by using special coating equipment, wherein the thickness of the copper foil is 6 mu m, performing clearance coating on the front surface and the back surface of the copper foil, and drying the coated pole piece to obtain a negative electrode pole piece B.
Respectively cutting the pole pieces A and B into small pieces with the length being more than or equal to 50mm and the width being more than or equal to 35mm by using a paper cutter; the pole piece material area faces upwards, the floating powder on the surface and the edge of the pole piece is cleaned up by using a small handheld dust collector, no obvious dust or foreign matters exist on the surface of the pole piece, then a transparent adhesive tape with the width of 20mm is covered at the central position of the surface of the pole piece material area, the central line of the adhesive tape in the width direction is ensured to be superposed with the central line of the pole piece in the width direction, the length of the adhesive tape needs to be about 1-2 cm longer than that of the pole piece, a press roller (2kg) with the diameter of 84mm and the height of 45mm is used for rolling the surface of the pole piece back and forth for 3 times. In order to prevent the abnormity in the stripping process, the pole piece and the transparent adhesive tape are slightly stripped for 5mm before formal stripping, a tensile machine is utilized to respectively clamp the current collector layer and the adhesive tape at the stripped end for 180-degree reverse stretching, and in the stripping process, the active substances are attached to the adhesive tape so as to be separated from the current collector.
And (3) respectively clamping one end of the separated conductive current collector and one end of the adhesive tape adhered with the active material by using a clamp of a universal tensile machine, performing 180-degree reverse stretching, automatically recording transient tensile force change in the whole process, and taking an average value, wherein the average peeling force of the sample A is 0.18 +/-0.02N/cm, and the average peeling force of the sample B is 0.24 +/-0.03N/cm.
The conductive current collectors stripped of the active materials are named as samples A 'and B', samples are taken from the positions 1/2-2/3 (calculated from the position where stripping starts) of the samples A 'and B', the samples are observed and photographed by a scanning electron microscope, and the back scattering mode is adopted, the magnification is 200 times, and the resolution is 1600 x 1200. Respectively processing the scanning electron microscope pictures of the samples A 'and B' by using Image Pro Plus of a graphic processing software, setting the judgment threshold value of light and dark pixels to be 128/256, and then automatically reading the ratio of the dark pixels in the samples A 'and B' to all the pixels by the software, wherein the numerical value of the sample A 'is 33.6 percent, and the numerical value of the sample B' is 42.9 percent. It can be seen that, after the adhesion with the transparent adhesive tape, more particles remained on the conductive current collector of sample B', and thus, the adhesion between the active material and the conductive current collector in electrode sample B was considered to be stronger. This conclusion is more consistent with the addition of styrene-butadiene rubber with adhesive effect in electrode sample B.
Example 2
The negative active material of the lithium ion battery, namely artificial graphite, carbon-coated silicon monoxide, thickener sodium carboxymethyl cellulose (CMCNa) and binder Styrene Butadiene Rubber (SBR) are mixed according to the weight ratio of 77.4: 20: 1.2: 1.4, adding a proper amount of deionized water (H)2O), forming stable and uniform fluid with certain viscosity, namely cathode slurry, by a high-speed shearing action with shearing capacity such as a planetary stirrer, a high-speed dispersion disc and the like; specially adapted for negative electrode pastesThe coating equipment is uniformly coated on a copper foil of a negative current collector, the thickness of the copper foil is 8 mu m, coating is carried out on the front surface and the back surface of the copper foil, the coated pole piece is dried, and the pole piece is rolled into a compacted density of 1.65g/cm by a double-roll machine3The electrode plate is the negative electrode plate C.
The negative electrode active material of the lithium ion battery, namely artificial graphite, carbon-coated silicon oxide, thickener lithium Polyacrylate (PAALi) and binder Styrene Butadiene Rubber (SBR) are mixed according to the weight ratio of 77.4: 20: 1.2: 1.4, adding a proper amount of deionized water (H)2O), forming stable and uniform fluid with certain viscosity, namely cathode slurry, by a high-speed shearing action with shearing capacity such as a planetary stirrer, a high-speed dispersion disc and the like; uniformly coating the negative electrode slurry on a copper foil of a negative electrode current collector by using special coating, wherein the thickness of the copper foil is 8 mu m, performing clearance coating on the front side and the back side of the copper foil, drying the coated pole piece, and rolling the pole piece into a compacted density of 1.65g/cm by using a double-roll machine3The electrode plate of (1) is the negative electrode plate D.
Respectively cutting the two pole pieces C and D into small pieces with the length being more than or equal to 50mm and the width being more than or equal to 35mm by using a paper cutter; the pole piece material area faces upwards, the floating powder on the surface and the edge of the pole piece is cleaned up by using a small handheld dust collector, no obvious dust or foreign matters exist on the surface of the pole piece, then a transparent adhesive tape with the width of 20mm is covered at the central position of the surface of the pole piece material area, the central line of the adhesive tape in the width direction is ensured to be superposed with the central line of the pole piece in the width direction, the length of the adhesive tape needs to be about 1-2 cm longer than that of the pole piece, a press roller (2kg) with the diameter of 84mm and the height of 45mm is used for rolling the surface of the pole piece back and forth for 3 times. In order to prevent the abnormity in the stripping process, the pole piece and the transparent adhesive tape are slightly stripped for 5mm before formal stripping, the current collector layer and the adhesive tape are respectively clamped by a tensile machine to carry out 180-degree reverse stretching, and in the stripping process, the active substances are attached to the adhesive tape to be separated from the current collector.
And (3) respectively clamping one end of the separated conductive current collector and one end of the adhesive tape adhered with the active material by using a clamp of a universal tensile machine, performing 180-degree reverse stretching, automatically recording transient tensile force change in the whole process, and taking an average value, wherein the average peeling force of the sample C is 0.68 +/-0.25N/cm, and the average peeling force of the sample D is 0.62 +/-0.22N/cm. In addition, the active material layer on the conductive current collector after peeling was observed to exhibit a partially exposed foil substrate, a partially stuck active material layer, and a partially completely non-stuck active material layer. It can be seen that when the laminated pole pieces are tested by means of a tensile machine to measure adhesion, the test results may not be well suited to reach a definitive conclusion.
The current collectors stripped of the active materials are named as samples C 'and D', the samples are sampled from the positions 1/2-2/3 (calculated from the position where stripping starts) of the samples C 'and D', observed and photographed by a scanning electron microscope, and the back scattering mode is adopted, the magnification is 200 times, and the resolution is 1600 x 1200. The scanning electron microscope pictures of the samples C 'and D' are respectively processed by using a graphic processing software Image Pro Plus, the judgment threshold value of light and dark pixels is set to be 128/256, and then the software automatically reads the ratio of the dark pixels in the samples C 'and D' to all the pixels, wherein the numerical value of the sample C 'is 78.0%, and the numerical value of the sample D' is 88.2%. From this, it can be seen that more particles remained on the conductive current collector of sample D' after the bonding with the transparent adhesive tape, and therefore, the bonding force between the active material and the conductive current collector in electrode sample D is considered to be stronger. This conclusion is consistent with the additional presence of lithium polyacrylate binder in electrode sample D and is therefore reliable.
Example 3
A positive active material of nickel-cobalt-manganese ternary material (Li (Ni)1/3Mn1/3Co1/3)O2) Conductive carbon black (SuperP) with conductive agent and thickener/binder polyvinylidene fluoride (PVDF) in a weight ratio of 97.0: 1.5: 1.5, adding a proper amount of N-methyl pyrrolidone (NMP), and forming a stable and uniform fluid with a certain viscosity, namely the anode slurry, by the high-speed shearing action of equipment with shearing capacity, such as a planetary stirrer, a high-speed dispersion disc and the like; the positive electrode slurry is uniformly coated on an aluminum foil of a positive electrode current collector by using special coating, the thickness of the aluminum foil is 12 mu m, and the positive and negative surfaces of the aluminum foil are coated with the coating at intervalsAnd drying the pole piece after being distributed to obtain the positive pole piece E.
A positive active material of nickel-cobalt-manganese ternary material (Li (Ni)1/3Mn1/3Co1/3)O2) With the conductive agent Carbon Nanotubes (CNTs) and the thickener/binder polyvinylidene fluoride (PVDF) at a weight ratio of 98.0: 0.5: 1.5, adding a proper amount of N-methyl pyrrolidone (NMP), and forming a stable and uniform fluid with a certain viscosity, namely the anode slurry, by the high-speed shearing action of equipment with shearing capacity, such as a planetary stirrer, a high-speed dispersion disc and the like; and uniformly coating the positive slurry on an aluminum foil of a positive current collector by using special coating, wherein the thickness of the aluminum foil is 12 mu m, performing gap coating on the front surface and the back surface of the aluminum foil, and drying the coated pole piece to obtain a positive pole piece F.
Cutting the two pole pieces E and F into small pieces with the length being more than or equal to 50mm and the width being more than or equal to 35mm by a paper cutter; the pole piece material area faces upwards, the floating powder on the surface and the edge of the pole piece is cleaned up by using a small handheld dust collector, no obvious dust or foreign matters exist on the surface of the pole piece, then a transparent adhesive tape with the width of 20mm is covered at the central position of the surface of the pole piece material area, the central line of the adhesive tape in the width direction is ensured to be superposed with the central line of the pole piece in the width direction, the length of the adhesive tape needs to be about 1-2 cm longer than that of the pole piece, a press roller (2kg) with the diameter of 84mm and the height of 45mm is used for rolling the surface of the pole piece back and forth for 3 times. In order to prevent the abnormity in the stripping process, the pole piece and the transparent adhesive tape are slightly stripped for 5mm before formal stripping, the current collector layer and the adhesive tape are respectively clamped by a tensile machine to carry out 180-degree reverse stretching, and in the stripping process, the active substances are attached to the adhesive tape to be separated from the current collector.
And (3) respectively clamping one end of the separated conductive current collector and one end of the adhesive tape adhered with the active material by using a clamp of a universal tensile machine, performing 180-degree reverse stretching, automatically recording transient tensile force change in the whole process, and taking an average value, wherein the average peeling force of the sample E is 0.35 +/-0.03N/cm, and the average peeling force of the sample F is 0.42 +/-0.03N/cm.
The current collectors stripped of the active materials are named as samples E 'and F', and samples are taken from the positions 1/2-2/3 (calculated from the position where stripping starts) of the samples E 'and F', observed and photographed by a scanning electron microscope, and the back scattering mode is adopted, the magnification is 200 times, and the resolution is 1600 x 1200. Processing the scanning electron microscope pictures of the samples C 'and D' respectively by using a graphics processing software Matlab, setting the judgment threshold value of light and dark pixels to be 128/256, and then automatically reading the ratio of the dark pixels in the samples E 'and F' to all the pixels by using the software, wherein the numerical value of the sample E 'is 53.8 percent, and the numerical value of the sample F' is 41.6 percent. Since the dark pixels represent the contrast of the Al element in the exposed Al foil conductive current collector in the positive electrode system, it can be known that more particles remain on the conductive current collector of the sample F' after the bonding of the transparent adhesive tape, and therefore, it can be considered that the bonding force between the active material and the conductive current collector is stronger in the electrode sample F, and the carbon nanotubes have an enhancing effect on the bonding effect of the electrode and the conductive current collector substrate. Meanwhile, the testing method is also proved to be simultaneously suitable for the positive electrode system and the negative electrode system of the battery.
The results of the 3 examples are summarized in the following table:
in light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.
Claims (4)
1. The detection method for the bonding effect between the lithium ion battery electrode and the electronic current collector is characterized in that:
the method comprises the following steps:
step 1: preparing a sample: cutting the electrode plate, wherein the material area of the electrode plate faces upwards, cleaning floating powder on the surface and the edge of the electrode plate, and ensuring that no obvious dust and foreign matters exist on the surface of the electrode plate to obtain a sample to be detected;
step 2: preparing an adhesive tape: selecting an adhesive tape, and ensuring that the width of the adhesive tape is smaller than that of the sample to be detected and the length of the adhesive tape is larger than that of the sample to be detected;
and step 3: gluing: covering an adhesive tape on the central position of the surface of the pole piece material area, ensuring that the central line of the adhesive tape in the width direction is superposed with the central line of the pole piece in the width direction, enabling two ends of the adhesive tape to exceed the corresponding ends of the pole piece, and rolling the surface of the pole piece or the adhesive tape back and forth by using a press roller to enable the adhesive tape to be in close contact with the surface of the pole piece;
and 4, step 4: stripping: respectively clamping a pole piece current collector layer and an adhesive tape layer by using a tensile machine, carrying out 180-degree reverse stretching, attaching active substances to the adhesive tape in a stripping process so as to be separated from the current collector, and naming the current collector stripped of the active substances as a detection sample;
and 5: sampling: sampling at the middle position of a detected sample, observing by using a scanning electron microscope and taking a picture;
step 6: selecting electrodes of the same type but different formulas, and repeating the steps 1-5 to respectively obtain a plurality of groups of photos;
and 7: after the magnified photos with the same times are taken, the magnified photos are processed by graphic processing software which can identify the contrast depth of the pixels of the graphics and count the number of the pixels, and the pixel number ratio of the residual particles of the electrodes with different formulas is obtained.
2. The method for detecting the bonding effect between the electrode of the lithium ion battery and the electronic current collector according to claim 1, wherein: in the step 5, the sampling position is selected from the position from the stripping start to 1/2-2/3 of the tail end of the pole piece.
3. The method for detecting the bonding effect between the electrode of the lithium ion battery and the electronic current collector according to claim 1, wherein: and a back scattering mode is required when the scanning electron microscope shoots the current collector.
4. The method for detecting the bonding effect between the electrode of the lithium ion battery and the electronic current collector according to claim 1, wherein: in the step 6, when a plurality of groups of samples to be detected are peeled, the peeling angle is consistent with the peeling speed.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111965092A (en) * | 2020-07-17 | 2020-11-20 | 重庆市紫建电子股份有限公司 | Method and device for detecting dust particles of pole piece |
| CN113029881A (en) * | 2021-04-12 | 2021-06-25 | 惠州亿纬创能电池有限公司 | Method and device for detecting dispersion effect of battery conductive agent |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1529917A (en) * | 2001-04-10 | 2004-09-15 | 三菱麻铁里亚尔株式会社 | Lithium ion polymer secondary battery, its electrode and method for synthesizing polymer compound in binder used in adhesion layer thereof |
| CN101399329A (en) * | 2007-09-26 | 2009-04-01 | 北京化工大学 | Positive pole plate of lithium-sulfur cell and manufacturing method thereof |
| CN102323249A (en) * | 2011-08-29 | 2012-01-18 | 东莞新能源科技有限公司 | Qualitative analysis method for adhesive property of adhesive |
| CN103326027A (en) * | 2013-05-29 | 2013-09-25 | 宁德新能源科技有限公司 | Lithium ion battery cathode and lithium ion battery |
| CN106769845A (en) * | 2016-12-27 | 2017-05-31 | 深圳市星源材质科技股份有限公司 | The characterizing method of cohesive force between a kind of polymer-coated lithium battery diaphragm and pole piece |
| WO2017193571A1 (en) * | 2016-05-12 | 2017-11-16 | 华为技术有限公司 | Conductive adhesive for lithium-ion battery and preparation method therefor, lithium-ion battery electrode plate and preparation method therefor, and lithium-ion battery |
| CN109632630A (en) * | 2017-10-09 | 2019-04-16 | 深圳先进技术研究院 | The test method and test equipment of battery pole piece adhesive force |
-
2019
- 2019-12-31 CN CN201911421110.4A patent/CN111175327B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1529917A (en) * | 2001-04-10 | 2004-09-15 | 三菱麻铁里亚尔株式会社 | Lithium ion polymer secondary battery, its electrode and method for synthesizing polymer compound in binder used in adhesion layer thereof |
| CN101399329A (en) * | 2007-09-26 | 2009-04-01 | 北京化工大学 | Positive pole plate of lithium-sulfur cell and manufacturing method thereof |
| CN102323249A (en) * | 2011-08-29 | 2012-01-18 | 东莞新能源科技有限公司 | Qualitative analysis method for adhesive property of adhesive |
| CN103326027A (en) * | 2013-05-29 | 2013-09-25 | 宁德新能源科技有限公司 | Lithium ion battery cathode and lithium ion battery |
| WO2017193571A1 (en) * | 2016-05-12 | 2017-11-16 | 华为技术有限公司 | Conductive adhesive for lithium-ion battery and preparation method therefor, lithium-ion battery electrode plate and preparation method therefor, and lithium-ion battery |
| CN106769845A (en) * | 2016-12-27 | 2017-05-31 | 深圳市星源材质科技股份有限公司 | The characterizing method of cohesive force between a kind of polymer-coated lithium battery diaphragm and pole piece |
| CN109632630A (en) * | 2017-10-09 | 2019-04-16 | 深圳先进技术研究院 | The test method and test equipment of battery pole piece adhesive force |
Non-Patent Citations (2)
| Title |
|---|
| I.V. BARSUKOV ET AL.: "NEW DEVELOPMENTS IN THE ADVANCED GRAPHITE FOR LITHIUM-ION BATTERIES", 《NEW CARBON BASED MATERIALS FOR ELECTROCHEMICAL ENERGY STORAGE SYSTEMS》 * |
| 周朝辉等: "PAA 黏结剂用于高比容量锂离子电池磷@碳负极", 《储能科学与技术》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111965092A (en) * | 2020-07-17 | 2020-11-20 | 重庆市紫建电子股份有限公司 | Method and device for detecting dust particles of pole piece |
| CN113029881A (en) * | 2021-04-12 | 2021-06-25 | 惠州亿纬创能电池有限公司 | Method and device for detecting dispersion effect of battery conductive agent |
| CN113029881B (en) * | 2021-04-12 | 2023-01-13 | 惠州亿纬创能电池有限公司 | Method and device for detecting dispersion effect of battery conductive agent |
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Denomination of invention: Testing method for the bonding effect between lithium-ion battery electrodes and electronic current collectors Granted publication date: 20220419 Pledgee: Lujiang County small and medium-sized enterprises financing Company limited by guarantee Pledgor: Boselis (Hefei) Co.,Ltd. Registration number: Y2024980004260 |