Thickness measuring device for double-layer coating sheet and use method

Abstract

The invention relates to a double-layer coating sheet thickness measuring device and a use method, the double-layer coating sheet thickness measuring device comprises a double-layer coating die head and a drying device, the double-layer coating die head comprises an upper die, a middle die, a lower die, a first material conveying channel and a second material conveying channel, one side of a coating assembly is provided with an X-ray thickness gauge, one side of the drying device is provided with a dual-energy ray thickness gauge, and the X-ray thickness gauge is provided with an X-ray thickness gauge. The dual-energy ray thickness gauge comprises a rack, a first upper sliding rail, a first lower sliding rail, a first sliding block, an X-ray generator, a second sliding block, an X-ray detector, a beta-ray detector, a beta-ray generator, a first turning roller and a second turning roller. A back roller is arranged on one side of the double-layer coating die head and provided with a rotary encoder, the first conveying channel is provided with a first conveying pipe, the first conveying pipe is provided with a first booster pump, the second conveying channel is provided with a second conveying pipe, and the second conveying pipe is provided with a second booster pump. And the surface density of the double-layer coated pole piece and the ratio of the carbon element to the silicon element can be fed back. The device is convenient to use and has a wide market prospect.

Description

Technical Field

[0001] The invention relates to the field of thickness measuring equipment for double-layer coated sheets, and in particular to a thickness measuring device for double-layer coated sheets and a use method thereof. Background Art

[0002] As an advanced electrode preparation process, double-layer coating technology has great potential in improving the performance of lithium batteries. Among them, the design of the binder layered structure is one of the key links in the double-layer coating process, which has an important impact on the structural integrity, cycle stability and electrochemical performance of the electrode. Double-layer coating is a process in which two slurries of different properties are coated on the current collector to form a double-layer structure electrode. This process can be used to design and optimize different layers of the electrode according to different needs.

[0003] Journal of Beijing Institute of Technology, Vol. 43, No. 12, December 2023, author: Bai Yu, Wang Mengyuan, Zhang Jing, Wang Zhenhua, titled "Research Progress of Silicon-Based Anodes for Lithium-Ion Batteries" The latest research progress is reviewed from three aspects: binders, surface modification of silicon materials, and silicon-carbon composites, thus providing theoretical verification for the application of silicon-based anodes as a next-generation anode material for a low-cost, high-capacity, and low-voltage platform.

[0004] The technology mentioned in the document specifically involves two slurries. The first slurry is a carbon black-containing slurry as the bottom layer, and the second slurry is a silicon-containing slurry coated on the bottom layer. During the production process, the two slurries are coated simultaneously, and the liquid supply ratio of the two slurries should be fed back in time during the coating process to meet the technical requirements for the production of double-layer coated pole pieces. In the prior art, there is a lack of corresponding technical means for the liquid supply ratio of the two slurries coated simultaneously, so as to provide an improved space utilization to measure the ratio between carbon and silicon elements, and then feedback the liquid supply ratio of the two slurries, so that on the basis of the feedback surface density data, data can be given to timely adjust the liquid supply ratio of the two slurries, thereby improving the qualified rate of the pole piece. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a thickness measuring device and a method for using a double-layer coated sheet that can provide feedback on the surface density of a lithium battery negative electrode and the ratio of carbon and silicon elements, so as to overcome the defects in the prior art.

[0006] The technical solution adopted by the present invention is: a thickness measuring device for a double-layer coated sheet, comprising a double-layer coating die head and a drying device, wherein the double-layer coating die head comprises an upper die, a middle die, a lower die, a first material feeding channel arranged on the lower die and a second material feeding channel arranged on the upper die, an X-ray thickness gauge is arranged on the side of the coating component away from the drying device, a dual-energy ray thickness gauge is arranged on the side of the drying device away from the coating component, the dual-energy ray thickness gauge comprises a frame, a first upper slide rail arranged on the frame, a first lower slide rail arranged below the first upper slide rail, a first slider arranged on the first upper slide rail, and an X-ray A generator, a second slider arranged on the first lower sliding rail, an X-ray detector arranged on the side of the second slider facing the X-ray generator, a β-ray detector arranged on one side of the X-ray detector, a β-ray generator arranged above the β-ray detector, a first steering roller arranged on the side of the β-ray detector away from the X-ray detector, and a second steering roller arranged on the side of the X-ray detector away from the β-ray detector; a back roller is arranged on one side of the double-layer coating die head, a rotary encoder is arranged on the back roller, a first feeding channel is arranged with a first conveying pipe, a first booster pump is arranged on the first conveying pipe, a second feeding channel is arranged with a second conveying pipe, and a second booster pump is arranged on the second conveying pipe.

[0007] Preferably, the dual-energy ray thickness gauge also includes an upper bracket arranged between the X-ray generator and the first slider, a lower bracket arranged between the X-ray detector and the second slider, a first linear drive device arranged between the upper bracket and the β-ray generator, and a second linear drive device arranged between the lower bracket and the β-ray detector; the first linear drive device and the second linear drive device each include a sub-bracket, a third slide rail arranged on the sub-bracket, a third slider arranged on the third slide rail, a first threaded screw arranged on the third slider and the sub-bracket, and a first servo motor arranged on the first threaded screw.

[0008] Preferably, the first upper slide rail and the first lower slide rail are parallel, the frame on one side of the first slider and the second slider is provided with a first rotating shaft, the frame on the other side of the first slider is provided with a second rotating shaft, the frame on the other side of the second slider is provided with a third rotating shaft, the first rotating shaft is provided with a first synchronous pulley and a second synchronous pulley, the second rotating shaft is provided with a third synchronous pulley, the third rotating shaft is provided with a fourth synchronous pulley, the first synchronous pulley, the third synchronous pulley and the first slider are provided with a first synchronous belt, the second synchronous pulley, the fourth synchronous pulley and the second slider are provided with a second synchronous belt, and the first rotating shaft is transmission-connected with a second servo motor.

[0009] Preferably, the dual-energy X-ray thickness gauge further comprises a second upper slide rail arranged on the side of the frame facing the β-ray generator, a fourth slide rail arranged on the second upper slide rail and the β-ray generator, a second lower slide rail arranged on the side of the frame facing the β-ray detector, and a fifth slide rail arranged on the second lower slide rail and the β-ray detector; second threaded screws are respectively arranged on the first slide rail and the frame, the second slide rail and the frame, the fourth slide rail and the frame, and the fifth slide rail and the frame, and each second threaded screw is respectively arranged with a third servo motor.

[0010] Preferably, the first steering roller and the second steering roller are both horizontally mounted on the frame, and the central axis of the gap between the β-ray detector and the β-ray generator, the central axis of the gap between the X-ray generator and the X-ray detector, the top of the first steering roller and the top of the second steering roller are located in the same plane.

[0011] A method for using the thickness measuring device of the double-layer coated sheet as described above comprises the following steps: S1. Mark the non-coating area at the edge of the copper foil. When the mark reaches the position of the X-ray thickness gauge, the X-ray thickness gauge continuously measures the thickness. Then, the copper foil after the thickness measurement by the X-ray thickness gauge is continuously conveyed to the bottom of the coating assembly. The first slurry enters the first conveying pipe, is pressurized by the first booster pump, enters the first feeding channel, and is coated on the copper foil passing through the gap between the middle mold and the lower mold to form a first coating layer. At the same time, the second slurry enters the second feeding channel through the second conveying pipe, is pressurized by the second booster pump, and is coated on the first coating layer through the gap between the upper mold and the middle mold to form a second coating layer. S2, the copper foil carrying the first coating layer and the second coating layer are continuously fed into the drying device for curing, wherein the first coating layer is cured to form a first cured layer, and the second coating layer is cured to form a second cured layer; S3, after the copper foil loads the first solidified layer and the second solidified layer and is guided by the second steering roller, the parameters fed back by the rotary encoder on the back roller are combined with the time when the mark of the non-coated area at the edge of the copper foil reaches the area where the gap between the X-ray generator and the X-ray detector is located, and the X-ray generator and the X-ray detector make reciprocating linear motion along the direction parallel to the first upper slide rail; the parameters fed back by the rotary encoder on the back roller are combined with the time when the mark of the non-coated area at the edge of the copper foil reaches the area where the gap between the X-ray β-ray detector and the β-ray generator is located, and the β-ray detector and the β-ray generator make reciprocating linear motion along the direction parallel to the first upper slide rail; the copper foil loads the first solidified layer and the second solidified layer and is guided by the first steering roller in turn and is sent to the downstream; Wherein, in step S3, the X-ray generator performs linear reciprocating motion, the X-ray generator and the X-ray detector, as well as the β-ray detector and the β-ray generator perform repeated multiple synchronous linear reciprocating motions, during which the X-ray generator is always located above the X-ray detector, the β-ray generator is always located above the β-ray detector, and the moving speed of the X-ray generator is equal to the moving speed of the β-ray generator; the distance between the X-ray generator and the β-ray generator along the direction parallel to the extension of the first upper slide rail is always ; The ,in It is the speed parameter calculated based on the parameter fed back by the rotary encoder. is the circumference of the backing roller, and R is the radius of the backing roller; is the moving speed of the X-ray generator and X-ray detector, The distance between the X-ray generator and the beta-ray generator along a direction perpendicular to the extension direction of the first upper slide rail; The time interval for the feedback of the same point data by the β-ray detector and the X-ray detector satisfies ; in, It is the speed parameter calculated based on the parameter fed back by the rotary encoder. is the circumference of the second turning roller, is the radius of the back roller, It is the distance between the X-ray generator and the β-ray generator along the direction perpendicular to the extension direction of the first upper slide rail.

[0012] Preferably, the X-rays emitted by the X-ray generator are successively absorbed by the second solidified layer, the first solidified layer and the copper foil and then fed back by the X-ray detector, and the attenuation law of the X-rays satisfies the relational expression 1: The relationship 1 is: ; in, The second solidified layer, the first solidified layer and the copper foil shield the X-ray detector to measure the X-ray count within a certain time interval. The copper foil at the measuring position blocks the X-ray thickness gauge's X-ray count within a certain time interval. The count of X-rays within a certain time interval measured by the X-ray detector is measured when the second solidified layer and the first solidified layer block the X-ray detector at the measuring position. It is the count of X-rays detected by the X-ray detector within a certain time interval when there is no obstruction. is the mass attenuation coefficient of the pole piece to X-rays (cm² / g), is the surface density of the electrode (g / cm), is the thickness of the electrode; The beta ray emitted by the beta ray generator is absorbed by the second solidified layer, the first solidified layer and the copper foil in sequence and then fed back by the beta ray detector. The attenuation law of the beta ray satisfies the relational expression 2: The second relational expression is: ; in, The count of beta rays within a certain time interval measured by the beta ray detector at the measuring position where the second solidified layer, the first solidified layer and the copper foil shielding the beta ray detector exist, The beta ray count that the beta ray detector can measure when the beta ray calculated based on the copper foil surface density parameter fed back by the X-ray thickness gauge only projects the copper foil at the measurement position. shielding the second solidified layer and the first solidified layer from the beta rays detected by the beta ray detector within a certain time interval, is the beta ray detected by the beta ray detector within a certain time interval when there is no obstruction. is the mass attenuation coefficient of the pole piece to β rays (cm² / g), is the surface density of the electrode (g / cm), is the thickness of the electrode; Assume that the mass fraction of the element with high atomic number in the electrode to be tested is , then the mass fraction of the element with low atomic number is According to the calculation rules of the mass attenuation coefficient of composite materials, the mass attenuation coefficient of the pole piece to X-rays is , the following relationship should be satisfied: The relationship three is in, is the mass attenuation coefficient of X-rays for elements with high atomic numbers in the pole piece, is the mass attenuation coefficient of the low atomic number elements in the pole piece to X-rays; further, the mass attenuation coefficient of the second solidified layer, the first solidified layer and the copper foil to low energy X-rays will increase with the increase of the high atomic number elements in the second solidified layer, the first solidified layer and the copper foil. Therefore, the logarithms of the relationship 1 and the relationship 2 are taken respectively, and the relationship 3 is brought in, and the relationship 4 is obtained after sorting. The relationship 4 is ; Let the silicon-carbon ratio in the second solidified layer, the first solidified layer and the copper foil be defined as , and have ; Thus we get relation 5: The relationship 5 is ; in ; ; ; The A is the slope coefficient, and the B is the intercept coefficient, which are related to the mass attenuation coefficient of X-rays and the mass attenuation coefficient of β-rays to elements with high atomic numbers and elements with low atomic numbers in the electrode. K is the ratio of the mass attenuation coefficients of the second solidified layer, the first solidified layer and the copper foil to X-rays and β-rays.

[0013] Preferably, the method further comprises the following steps: SS1, adjusting the rotation speeds of the first booster pump and the second booster pump until the first booster pump reaches a preset rotation speed V1 and the second booster pump reaches a preset rotation speed V2, and setting V2 equal to 0; then, maintaining the rotation speeds of the first booster pump and the second booster pump; then, sequentially executing steps S1 to S3, and recording the data fed back by the X-ray thickness gauge, the data fed back by the X-ray detector, and the data fed back by the beta-ray generator; SS2, keeping the speed V1 of the first booster pump unchanged, repeatedly and gradually adjusting the speed V2' of the second booster pump, keeping the speed V2' of the second booster pump stable after each adjustment, and executing steps S1 to S3 again, and recording the data fed back by the X-ray thickness gauge, the data fed back by the X-ray detector, and the data fed back by the β-ray generator again; SS3, calculate according to the data obtained in step SS1 and step SS2 and ; then according to The K value is calculated, and then the copper foils carrying the second cured layer and the first cured layer are cut and compared with the measured value to obtain the relational expression 5.

[0014] The beneficial effect of the present invention is that by comparing the actual weight with the calculated weight, it can be seen that the fifth relation has high reliability and stability, and can accurately predict the coating quality under different upper layer pump speed conditions. The error is within the experimental allowable range, which supports the application of the fifth relation in actual production. Thus, the fifth relation is used to further feedback the ratio of carbon and silicon in the negative electrode sheet on the basis of the surface density of the negative electrode sheet of the lithium battery.

[0015] The invention has the advantages of simple structure, convenient operation, ingenious design, greatly improved working efficiency, good social and economic benefits, and is a product that is easy to promote and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention.

[0017] Figure 2 It is a structural schematic diagram of the dual-energy ray thickness gauge of the present invention.

[0018] Figure 3 It is a structural schematic diagram of the dual-energy ray thickness gauge of the present invention.

[0019] Figure 4 It is a structural schematic diagram of the dual-energy ray thickness gauge of the present invention. DETAILED DESCRIPTION

[0020] Example 1: Figure 1 and Figure 2As shown, a thickness measuring device for a double-layer coated sheet comprises a double-layer coating die head and a drying device, wherein the double-layer coating die head comprises an upper die 1, a middle die 2, a lower die 3, a first material feeding channel 4 arranged on the lower die 3, and a second material feeding channel 5 arranged on the upper die 1, an X-ray thickness gauge 6 is arranged on the side of the coating component away from the drying device, and a dual-energy ray thickness gauge is arranged on the side of the drying device away from the coating component, and the dual-energy ray thickness gauge comprises a frame 7, a first upper slide rail 8 arranged on the frame 7, a first lower slide rail 9 arranged below the first upper slide rail 8, a first slider 10 arranged on the first upper slide rail 8, an X-ray generator 11 arranged on the side of the first slider 10 facing the first lower slide rail 9, and a second slider arranged on the first lower slide rail 9 12, an X-ray detector 13 arranged on the side of the second slider 12 facing the X-ray generator 11, a β-ray detector 14 arranged on the side of the X-ray detector 13, a β-ray generator 15 arranged above the β-ray detector 14, a first steering roller 16 arranged on the side of the β-ray detector 14 away from the X-ray detector 13, and a second steering roller 17 arranged on the side of the X-ray detector 13 away from the β-ray detector 14; a back roller 18 is arranged on one side of the double-layer coating die head, a rotary encoder 19 is arranged on the back roller 18, a first conveying pipe 20 is arranged on the first feeding channel 4, a first boosting pump 21 is arranged on the first conveying pipe 20, a second conveying pipe 22 is arranged on the second feeding channel 5, and a second boosting pump 23 is arranged on the second conveying pipe 22.

[0021] The dual-energy X-ray thickness gauge also includes a second upper slide rail 41 arranged on the side of the frame 7 facing the β-ray generator 15, a fourth slide block 42 arranged on the second upper slide rail 41 and the β-ray generator 15, a second lower slide rail 43 arranged on the side of the frame 7 facing the β-ray detector 14, and a fifth slide block 44 arranged on the second lower slide rail 43 and the β-ray detector 14; second threaded screws 45 are respectively arranged on the first slide block 10 and the frame 7, the second slide block 12 and the frame 7, the fourth slide block 42 and the frame 7, and the fifth slide block 44 and the frame 7, and each second threaded screw 45 is respectively provided with a third servo motor 46.

[0022] The first steering roller 16 and the second steering roller 17 are both horizontally mounted on the frame 7, and the central axis of the gap between the β-ray detector 14 and the β-ray generator 15, the central axis of the gap between the X-ray generator 11 and the X-ray detector 13, the top end of the first steering roller 16 and the top end of the second steering roller 17 are located in the same plane.

[0023] The method of using this product is as follows: Figure 1 and Figure 2 As shown, the following steps are included: S1. Mark the non-coating area at the edge of the copper foil. When the mark reaches the position of the X-ray thickness gauge 6, the X-ray thickness gauge 6 performs continuous thickness measurement. Then, the copper foil after the thickness measurement by the X-ray thickness gauge 6 is continuously conveyed to the bottom of the coating assembly. The first slurry enters the first conveying pipe 20 and is pressurized by the first booster pump 21. It enters the first feeding channel 4 and is coated on the copper foil passing through the gap between the middle mold 2 and the lower mold 3 to form a first coating layer. At the same time, the second slurry enters the second feeding channel 5 and is pressurized by the second booster pump 23 through the second conveying pipe 22. It passes through the gap between the upper mold 1 and the middle mold 2 and is coated on the top of the first coating layer to form a second coating layer. S2, the copper foil carrying the first coating layer and the second coating layer are continuously fed into the drying device for curing, wherein the first coating layer is cured to form a first cured layer, and the second coating layer is cured to form a second cured layer; S3, after the copper foil carrying the first solidified layer and the second solidified layer are guided by the second steering roller 17, the parameters fed back by the rotary encoder 19 on the back roller 18 are combined with the time when the mark of the non-coated area at the edge of the copper foil reaches the area where the gap between the X-ray generator 11 and the X-ray detector 13 is located, and the X-ray generator 11 and the X-ray detector 13 make reciprocating linear motion along the direction parallel to the first upper slide rail 8; the parameters fed back by the rotary encoder 19 on the back roller 18 are combined with the time when the mark of the non-coated area at the edge of the copper foil reaches the area where the gap between the X-ray β-ray detector 14 and the β-ray generator 15 is located, and the β-ray detector 14 and the β-ray generator 15 make reciprocating linear motion along the direction parallel to the first upper slide rail 8; the copper foil carrying the first solidified layer and the second solidified layer are sequentially sent to the downstream after passing through the gap between the X-ray generator 11 and the X-ray detector 13, the gap between the β-ray detector 14 and the β-ray generator 15, and the first steering roller 16 for guidance; In step S3, the X-ray generator 11 performs linear reciprocating motion, and the X-ray generator 11 and the X-ray detector 13 as well as the β-ray detector 14 and the β-ray generator 15 perform repeated multiple synchronous linear reciprocating motions, during which the X-ray generator 11 is always located above the X-ray detector 13, and the β-ray generator 15 is always located above the β-ray detector 14, and the moving speed of the X-ray generator 11 is equal to the moving speed of the β-ray generator 15; the distance between the X-ray generator 11 and the β-ray generator 15 along the extension direction parallel to the first upper slide rail 8 is always ; The ,in It is the speed parameter calculated based on the parameter fed back by the rotary encoder 19. is the circumference of the backing roller 18, and R is the radius of the backing roller 18; is the moving speed of the X-ray generator 11 and the X-ray detector 13, The distance between the X-ray generator 11 and the beta-ray generator 15 is perpendicular to the extending direction of the first upper slide rail 8; The time interval for the feedback of the same point data by the β-ray detector 14 and the X-ray detector 13 satisfies ; in, It is the speed parameter calculated based on the parameter fed back by the rotary encoder 19. is the circumference of the second turning roller 17, is the radius of the back roller 18, The X-ray generator 11 and the β-ray generator 15 are spaced apart along a distance perpendicular to the extending direction of the first upper rail 8 .

[0024] Furthermore, the X-rays emitted by the X-ray generator 11 are successively absorbed by the second solidified layer, the first solidified layer and the copper foil and then fed back by the X-ray detector 13. The attenuation law of the X-rays satisfies the relational expression 1: The relationship 1 is: ; in, The second solidified layer, the first solidified layer and the copper foil shield the X-ray detector 13 to measure the X-ray count within a certain time interval. The number of X-ray counts within a certain time interval measured by the X-ray thickness gauge 6 when there is copper foil blocking the measurement position. The count of X-rays within a certain time interval measured by the X-ray detector 13 is measured when the second solidified layer and the first solidified layer block the X-ray detector 13 at the measuring position. is the count of X-rays within a certain time interval detected by the X-ray detector 13 when there is no shielding, is the mass attenuation coefficient of the pole piece to X-rays (cm² / g), is the surface density of the electrode (g / cm), is the thickness of the electrode.

[0025] The beta rays emitted by the beta ray generator 15 are successively absorbed by the second solidified layer, the first solidified layer and the copper foil and then fed back by the beta ray detector 14. The attenuation law of the beta rays satisfies the relational expression 2: The second relational expression is: ; in, The count of beta rays within a certain time interval measured by the beta ray detector 14 when the second solidified layer, the first solidified layer and the copper foil shielding the beta ray detector 14 exist at the measuring position. The beta ray count that can be measured by the beta ray detector 14 when the beta ray calculated based on the copper foil surface density parameter fed back by the X-ray thickness gauge 6 only projects on the copper foil at the measuring position, The second solidified layer and the first solidified layer shield the beta rays detected by the beta ray detector 14 within a certain time interval, is the beta ray detected by the beta ray detector 14 within a certain time interval when there is no shielding, is the mass attenuation coefficient of the pole piece to β rays (cm² / g), is the surface density of the electrode (g / cm), is the thickness of the electrode; Assume that the mass fraction of the element with high atomic number in the electrode to be tested is , then the mass fraction of the element with low atomic number is According to the calculation rules of the mass attenuation coefficient of composite materials, the mass attenuation coefficient of the pole piece to X-rays is , the following relationship should be satisfied: The relationship three is in, is the mass attenuation coefficient of X-rays for elements with high atomic numbers in the pole piece, is the mass attenuation coefficient of the low atomic number elements in the pole piece to X-rays; further, the mass attenuation coefficient of the second solidified layer, the first solidified layer and the copper foil to low energy X-rays will increase with the increase of the high atomic number elements in the second solidified layer, the first solidified layer and the copper foil. Therefore, the logarithms of the relationship 1 and the relationship 2 are taken respectively, and the relationship 3 is brought in, and the relationship 4 is obtained after sorting. The relationship 4 is ; Let the silicon-carbon ratio in the second solidified layer, the first solidified layer and the copper foil be defined as , and have ; Thus we get relation 5: The relationship 5 is ; in ; ; ; The A is the slope coefficient, and the B is the intercept coefficient, which are related to the mass attenuation coefficient of X-rays and the mass attenuation coefficient of β-rays to elements with high atomic numbers and elements with low atomic numbers in the electrode. K is the ratio of the mass attenuation coefficients of the second solidified layer, the first solidified layer and the copper foil to X-rays and β-rays.

[0026] When the product continuously performs online measurement on the copper foil attached with the second solidified layer and the first solidified layer using equation 5, it is necessary to obtain the measured data. and ; and then according to The K value is calculated so that the measured data of the second solidified layer, the first solidified layer and the copper foil can be corrected by using the relational expression 5, which specifically includes the following steps: SS1, adjust the speed of the first booster pump 21 and the second booster pump 23 until the first booster pump 21 reaches a preset speed V1 and the preset speed of the second booster pump 23 is V2, and set V2 equal to 0; then, maintain the speed of the first booster pump 21 and the second booster pump 23; then, perform steps S1 to S3 in sequence, and record the data fed back by the X-ray thickness gauge 6, the data fed back by the X-ray detector 13, and the data fed back by the β-ray generator 15, and convert them into weight to obtain Table 1, as shown below: SS2, keep the speed V1 of the first boosting pump 21 unchanged, repeatedly and gradually adjust the speed V2' of the second boosting pump 23, keep the speed V2' of the second boosting pump 23 stable after each adjustment, and execute steps S1 to S3 again, and record the data fed back by the X-ray thickness gauge 6, the data fed back by the X-ray detector 13 and the data fed back by the β-ray generator 15 again; and record the data fed back by the X-ray thickness gauge 1, the data fed back by the X-ray detector 13 and the data fed back by the β-ray generator 15 again, convert them into weight and obtain Table 2, as shown below: The net weight measured after changing the preset speed V2' of the second boosting pump 23 is subtracted from the net weight of the first coating layer formed by only using the preset speed V1 of the first boosting pump 21 after curing to form the first cured layer, to obtain the net weight of the second coating layer and its proportion in the total coating weight composed of the first cured layer and the second cured layer. The calculation results are shown in Table 3: SS3, calculate according to the data obtained in step SS1 and step SS2 and ; then according to The K value is calculated as shown in Table 4, and then the copper foil of the second cured layer and the first cured layer loaded with the cut is compared with the measured value to obtain the relational expression 5.

[0027] With the actual silicon-carbon ratio and K values, we can use the least square method to derive their relationship. After determining the silicon-carbon ratio formula, we simultaneously change the speed V3 of the first booster pump 21 and the speed V4 of the second booster pump 23, and then set V3=V4 to calculate the silicon-carbon ratio and deduce the theoretical weight of the upper layer. Compare the calculated results with the actual weight when only the upper layer is applied to verify the accuracy of the formula, as shown in Table 5: The silicon-carbon ratio calculated using equation 5 and the estimated upper layer weight are shown in Table 6: Adjust the rotation speed V5 of the first boost pump 21 to zero, and fine-tune the rotation speed V6 of the second boost pump 23, and set V6=V3, execute steps S1 to S3 again to apply and measure using the weight method, as shown in Table VII, and use relationship 5 to correct the measurement data in the above process to obtain the calculated upper layer weight and compare it with the actual upper layer weight measured using the weight method, as shown in Table VIII.

[0028] According to the information in Table 8, the error range between the upper layer weight calculated by equation 5 and the actual upper layer weight is obtained, including an absolute error of +0.29g to +0.59g; a relative error of -0.52% to +0.73%; the relative errors are all controlled within 1%, indicating that the deviation between the calculated value and the actual value is very small, which meets the experimental accuracy requirements. According to the information in Table 8, the deviation distribution is obtained, among which the calculated values ​​of groups 1, 2 and 5 are slightly lower than the actual values, which may be related to the slight fluctuation of the upper layer pump speed in the experimental conditions; the overall deviation has no obvious systematic trend, which verifies the applicability of equation 5.

[0029] Through Example 1, by comparing the actual weight with the calculated weight, it can be seen that Relational Formula 5 has high reliability and stability, and can accurately predict the coating quality under different upper layer pump speed conditions. The error is within the experimental allowable range, which supports the application of Relational Formula 5 in actual production. Thus, it is realized that the ratio of carbon and silicon elements in the negative electrode sheet of the lithium battery is further fed back by using Relational Formula 5 on the basis of the surface density of the negative electrode sheet of the lithium battery.

[0030] Example 2: Figure 1 , Figure 3 and Figure 4As shown, compared with Example 1, a thickness measuring device for a double-layer coated sheet in this embodiment comprises a double-layer coating die head and a drying device, wherein the double-layer coating die head comprises an upper die 1, a middle die 2, a lower die 3, a first material feeding channel 4 arranged on the lower die 3, and a second material feeding channel 5 arranged on the upper die 1, and is characterized in that: an X-ray thickness gauge 6 is arranged on the side of the coating component away from the drying device, and a dual-energy ray thickness gauge is arranged on the side of the drying device away from the coating component, and the dual-energy ray thickness gauge comprises a frame 7, a first upper slide rail 8 arranged on the frame 7, a first lower slide rail 9 arranged below the first upper slide rail 8, a first slider 10 arranged on the first upper slide rail 8, an X-ray generator 11 arranged on the side of the first slider 10 facing the first lower slide rail 9, and a first slider 12 arranged on the side of the first slider 10 facing the first lower slide rail 9. a second slider 12 arranged on the rail 9, an X-ray detector 13 arranged on the side of the second slider 12 facing the X-ray generator 11, a β-ray detector 14 arranged on one side of the X-ray detector 13, a β-ray generator 15 arranged above the β-ray detector 14, a first steering roller 16 arranged on the side of the β-ray detector 14 away from the X-ray detector 13, and a second steering roller 17 arranged on the side of the X-ray detector 13 away from the β-ray detector 14; a back roller 18 is arranged on one side of the double-layer coating die head, a rotary encoder 19 is arranged on the back roller 18, a first conveying pipe 20 is arranged on the first feeding channel 4, a first boosting pump 21 is arranged on the first conveying pipe 20, a second conveying pipe 22 is arranged on the second feeding channel 5, and a second boosting pump 23 is arranged on the second conveying pipe 22. The above is consistent with Example 1, but different from Example 1 is that the dual-energy ray thickness gauge in Example 2 also includes an upper bracket 24 arranged between the X-ray generator 11 and the first slider 10, a lower bracket 25 arranged between the X-ray detector 13 and the second slider 12, a first linear drive device arranged between the upper bracket 24 and the β-ray generator 15, and a second linear drive device arranged between the lower bracket 25 and the β-ray detector 14; the first linear drive device and the second linear drive device both include a sub-bracket 26, a third slide rail 27 arranged on the sub-bracket 26, a third slider 28 arranged on the third slide rail 27, a first threaded screw 29 arranged on the third slider 28 and the sub-bracket 26, and a first servo motor 30 arranged on the first threaded screw 29.The first upper slide rail 8 is parallel to the first lower slide rail 9, and the frame 7 on one side of the first slider 10 and the second slider 12 is provided with a first rotating shaft 31, and the frame 7 on the other side of the first slider 10 is provided with a second rotating shaft 32, and the frame 7 on the other side of the second slider 12 is provided with a third rotating shaft 33, and the first rotating shaft 31 is provided with a first synchronous pulley 34 and a second synchronous pulley 35, and the second rotating shaft 32 is provided with a third synchronous pulley 36, and the third rotating shaft 33 is provided with a fourth synchronous pulley 37, and the first synchronous pulley 34, the third synchronous pulley 36 and the first slider 10 are provided with a first synchronous belt 38, and the second synchronous belt pulley 35, the fourth synchronous pulley 37 and the second slider 12 are provided with a second synchronous belt 39, and the first rotating shaft 31 is transmission-connected with a second servo motor 40.

[0031] Different from step S3 of embodiment 1, embodiment 2 adopts step S3 、 Step S3 in the alternative embodiment 1 is replaced, and the other steps remain the same. Specifically, step S3 、 , the copper foil carrying the first solidified layer and the second solidified layer are guided by the second turning roller 17 and then sequentially passed through the gap between the X-ray generator 11 and the X-ray detector 13, the gap between the β-ray detector 14 and the β-ray generator 15, and the first turning roller 11 and then sent downstream; Among them, in step S3, the X-ray generator 11 performs linear reciprocating motion, and the X-ray detector 13, the β-ray detector 14 and the β-ray generator 15 all perform repeated synchronous linear reciprocating motions with the X-ray generator 11. During this period, the X-ray generator 11 is always located above the X-ray detector 13, and the β-ray generator 15 is always located above the β-ray detector 14. The linear reciprocating motion includes one forward movement and one reverse movement, and the data acquisition stage of the X-ray detector 13 and the β-ray detector 14 is only collected in one forward movement. When executing a reverse movement in the linear reciprocating motion, the corresponding first linear motor 24 completes a reverse movement at maximum power to quickly reset it. The distance between the X-ray generator 11 and the β-ray generator 15 along the extension direction parallel to the first upper slide rail 8 is always .

[0032] The second servo motor 40 drives the first rotating shaft 31 to rotate, and the first rotating shaft 31 drives the first synchronous pulley 34 and the second synchronous pulley 35 to rotate at the same time, thereby driving the second synchronous belt 39 and the first synchronous belt 38 to move, and then driving the first slider 10 and the second slider 12 to move synchronously, thereby driving the X-ray generator 11, the X-ray detector 13, the β-ray detector 14 and the β-ray generator 15 to move synchronously. The function of the first linear drive device is to adjust the distance between the X-ray generator 11 and the β-ray generator 15; the function of the second linear drive device is to adjust the distance between the X-ray detector 13 and the β-ray detector 14.

[0033] Compared with Example 1, Example 2 reduces the system error and improves the accuracy of the feedback of the X-ray detector 13 and the β-ray detector 14 on the same measurement point.

[0034] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made according to the structures, features and principles described in the patent scope of the present invention should be included in the scope of the patent application of the present invention.

Claims

1. A device for measuring the thickness of a double-layer coated sheet, comprising a double-layer coated die head and a drying device, wherein the double-layer coated die head comprises an upper die (1), a middle die (2), a lower die (3), a first material feeding channel (4) provided on the lower die (3) and a second material feeding channel (5) provided on the upper die (1), characterized in that: An X-ray thickness gauge (6) is arranged on a side of the coating component away from the drying device, and a dual-energy ray thickness gauge is arranged on a side of the drying device away from the coating component. The dual-energy ray thickness gauge comprises a frame (7), a first upper slide rail (8) arranged on the frame (7), a first lower slide rail (9) arranged below the first upper slide rail (8), a first slider (10) arranged on the first upper slide rail (8), an X-ray generator (11) arranged on a side of the first slider (10) facing the first lower slide rail (9), a second slider (12) arranged on the first lower slide rail (9), an X-ray detector (13) arranged on a side of the second slider (12) facing the X-ray generator (11), and a detector (13) arranged on one side of the X-ray detector (13). A beta-ray detector (14) is disposed on the first side of the beta-ray detector (14), a beta-ray generator (15) is disposed above the beta-ray detector (14), a first steering roller (16) is disposed on the side of the beta-ray detector (14) away from the X-ray detector (13), and a second steering roller (17) is disposed on the side of the X-ray detector (13) away from the beta-ray detector (14); a back roller (18) is disposed on one side of the double-layer coating die head, a rotary encoder (19) is disposed on the back roller (18), a first conveying pipe (20) is disposed on the first conveying pipe (20), a first boosting pump (21) is disposed on the first conveying pipe (20), a second conveying pipe (22) is disposed on the second conveying channel (5), and a second boosting pump (23) is disposed on the second conveying pipe (22).

2. The thickness measuring device for a double-layer coated sheet according to claim 1, characterized in that: The dual-energy ray thickness gauge further comprises an upper bracket (24) arranged between the X-ray generator (11) and the first slider (10), a lower bracket (25) arranged between the X-ray detector (13) and the second slider (12), a first linear drive device arranged between the upper bracket (24) and the β-ray generator (15), and a second linear drive device arranged between the lower bracket (25) and the β-ray detector (14); the first linear drive device and the second linear drive device both comprise a sub-bracket (26), a third slide rail (27) arranged on the sub-bracket (26), a third slider (28) arranged on the third slide rail (27), a first threaded lead screw (29) arranged on the third slider (28) and the sub-bracket (26), and a first servo motor (30) arranged on the first threaded lead screw (29).

3. The thickness measuring device for a double-layer coated sheet according to claim 2, characterized in that: The first upper slide rail (8) and the first lower slide rail (9) are parallel to each other; a frame (7) on one side of the first slider (10) and the second slider (12) is provided with a first rotating shaft (31); a frame (7) on the other side of the first slider (10) is provided with a second rotating shaft (32); a frame (7) on the other side of the second slider (12) is provided with a third rotating shaft (33); a first synchronous pulley (34) and a second synchronous pulley (35) are provided on the first rotating shaft (31); a third synchronous pulley (36) is provided on the second rotating shaft (32); a fourth synchronous pulley (37) is provided on the third rotating shaft (33); a first synchronous belt (38) is provided on the first synchronous pulley (34), the third synchronous pulley (36) and the first slider (10); a second synchronous belt (39) is provided on the second synchronous pulley (35), the fourth synchronous pulley (37) and the second slider (12); and a second servo motor (40) is transmission-connected to the first rotating shaft (31).

4. The thickness measuring device for a double-layer coated sheet according to claim 1, characterized in that: The dual-energy radiographic thickness gauge further comprises a second upper slide rail (41) arranged on the side of the frame (7) facing the β-ray generator (15), a fourth slide block (42) arranged on the second upper slide rail (41) and the β-ray generator (15), a second lower slide rail (43) arranged on the side of the frame (7) facing the β-ray detector (14), and a fifth slide block (44) arranged on the second lower slide rail (43) and the β-ray detector (14); second threaded lead screws (45) are respectively arranged on the first slide block (10) and the frame (7), the second slide block (12) and the frame (7), the fourth slide block (42) and the frame (7), and the fifth slide block (44) and the frame (7), and each second threaded lead screw (45) is respectively arranged on a third servo motor (46).

5. The thickness measuring device for a double-layer coated sheet according to claim 1, characterized in that: The first steering roller (16) and the second steering roller (17) are both horizontally mounted on the frame (7); the first steering roller (16) and the second steering roller (17) are parallel to each other; the first steering roller (16) and the first upper slide rail (8) are perpendicular to each other; the central axis of the gap between the β-ray detector (14) and the β-ray generator (15), the central axis of the gap between the X-ray generator (11) and the X-ray detector (13), the top end of the first steering roller (16) and the top end of the second steering roller (17) are located in the same plane.

6. A method for using the thickness measuring device for a double-layer coated sheet as claimed in claim 1, characterized in that: The following steps are included: S1. A mark is made on the non-coating area at the edge of the copper foil. When the mark reaches the position of the X-ray thickness gauge (6), the X-ray thickness gauge (6) continuously measures the thickness. Then, the copper foil after the thickness measurement by the X-ray thickness gauge (6) is continuously transported to the bottom of the coating assembly. The first slurry enters the first conveying pipe (20) and is pressurized by the first booster pump (21). The first slurry enters the first material delivery channel (4) and is coated on the copper foil passing through the gap between the middle mold (2) and the lower mold (3) to form a first coating layer. At the same time, the second slurry enters the second material delivery channel (5) through the second conveying pipe (22) and is pressurized by the second booster pump (23). The second slurry enters the second material delivery channel (5) and is coated on the top of the first coating layer through the gap between the upper mold (1) and the middle mold (2) to form a second coating layer. S2, the copper foil carrying the first coating layer and the second coating layer are continuously fed into the drying device for curing, wherein the first coating layer is cured to form a first cured layer, and the second coating layer is cured to form a second cured layer; S3, after the copper foil is loaded with the first solidified layer and the second solidified layer and guided by the second steering roller (17), the parameters fed back by the rotary encoder (19) on the back roller (18) are combined with the time when the mark of the non-coated area at the edge of the copper foil reaches the area where the gap between the X-ray generator (11) and the X-ray detector (13) is located, and the X-ray generator (11) and the X-ray detector (13) perform reciprocating linear motion in a direction parallel to the first upper slide rail (8); the parameters fed back by the rotary encoder (19) on the back roller (18) are combined with the time when the mark of the non-coated area at the edge of the copper foil reaches the area where the gap between the X-ray generator (11) and the X-ray detector (13) is located; The time when the mark of the non-coated area at the edge of the foil reaches the area where the gap between the X-ray β-ray detector (14) and the β-ray generator (15) is located, the β-ray detector (14) and the β-ray generator (15) perform reciprocating linear motion in a direction parallel to the first upper slide rail (8); the copper foil carrying the first solidified layer and the second solidified layer sequentially pass through the gap between the X-ray generator (11) and the X-ray detector (13), the gap between the β-ray detector (14) and the β-ray generator (15), and the first steering roller (16) for guidance and then are sent downstream; In step S3, the X-ray generator (11) performs linear reciprocating motion, the X-ray generator (11) and the X-ray detector (13), as well as the β-ray detector (14) and the β-ray generator (15) perform repeated multiple synchronous linear reciprocating motions, during which the X-ray generator (11) is always located above the X-ray detector (13), the β-ray generator (15) is always located above the β-ray detector (14), and the moving speed of the X-ray generator (11) is equal to the moving speed of the β-ray generator (15); and the distance between the X-ray generator (11) and the β-ray generator (15) along the extension direction parallel to the first upper slide rail (8) is always ; The ,in It is the speed parameter calculated based on the parameter fed back by the rotary encoder (19). is the circumference of the back roller (18), and R is the radius of the back roller (18); is the moving speed of the X-ray generator (11) and the X-ray detector (13), The distance between the X-ray generator (11) and the beta-ray generator (15) along a direction perpendicular to the extension direction of the first upper slide rail (8); The time interval for the beta ray detector (14) and the X-ray detector (13) to feedback data at the same point satisfies ; in, It is the speed parameter calculated based on the parameter fed back by the rotary encoder (19). is the circumference of the second turning roller (17), is the radius of the backing roller (18), The distance between the X-ray generator (11) and the beta-ray generator (15) is perpendicular to the extension direction of the first upper slide rail (8).

7. The method for using the thickness measuring device for a double-layer coated sheet according to claim 6, characterized in that: The X-rays emitted by the X-ray generator (11) are absorbed by the second solidified layer, the first solidified layer and the copper foil in sequence and then fed back by the X-ray detector (13). The attenuation law of the X-rays satisfies the relational expression 1: The relationship 1 is: ; in, The count of X-rays within a certain time interval measured by the X-ray detector (13) at the measurement position where the second solidified layer, the first solidified layer and the copper foil shield the X-ray detector (13), The number of X-ray counts within a certain time interval measured by the X-ray thickness gauge (6) when there is copper foil blocking the measurement position. The count of X-rays within a certain time interval measured by the X-ray detector (13) is determined when the second solidified layer and the first solidified layer block the X-ray detector (13) at the measuring position. is the count of X-rays detected by the X-ray detector (13) within a certain time interval when there is no shielding, is the mass attenuation coefficient of the pole piece to X-rays (cm² / g), is the surface density of the electrode (g / cm), is the thickness of the electrode; The beta rays emitted by the beta ray generator (15) are absorbed by the second solidified layer, the first solidified layer and the copper foil in sequence and then fed back by the beta ray detector (14). The attenuation law of the beta rays satisfies the relational expression 2: The second relational expression is: ; in, The count of beta rays within a certain time interval measured by the beta ray detector (14) at the measuring position where the second solidified layer, the first solidified layer and the copper foil shielding the beta ray are present, The beta ray count that can be measured by the beta ray detector (14) when the beta ray calculated based on the copper foil surface density parameter fed back by the X-ray thickness gauge (6) is projected only on the copper foil at the measurement position, The second solidified layer and the first solidified layer shield the beta rays detected by the beta ray detector (14) within a certain time interval, is the beta ray detected by the beta ray detector (14) within a certain time interval when there is no shielding, is the mass attenuation coefficient of the pole piece to β rays (cm² / g), is the surface density of the electrode (g / cm), is the thickness of the electrode; Assume that the mass fraction of the element with high atomic number in the electrode to be tested is , then the mass fraction of the element with low atomic number is According to the calculation rules of the mass attenuation coefficient of composite materials, the mass attenuation coefficient of the pole piece to X-rays is , the following relationship should be satisfied: The relationship three is in, is the mass attenuation coefficient of X-rays for elements with high atomic numbers in the pole piece, is the mass attenuation coefficient of the low atomic number elements in the pole piece to X-rays; further, the mass attenuation coefficient of the second solidified layer, the first solidified layer and the copper foil to low energy X-rays will increase with the increase of the high atomic number elements in the second solidified layer, the first solidified layer and the copper foil. Therefore, the logarithms of the relationship 1 and the relationship 2 are taken respectively, and the relationship 3 is brought in, and the relationship 4 is obtained after sorting. The relationship 4 is ; Let the silicon-carbon ratio in the second solidified layer, the first solidified layer and the copper foil be defined as , and have ; Thus we get relation 5: The relationship 5 is = ; in ; ; ; The A is the slope coefficient, and the B is the intercept coefficient, which are related to the mass attenuation coefficient of X-rays and the mass attenuation coefficient of β-rays to elements with high atomic numbers and elements with low atomic numbers in the electrode. K is the ratio of the mass attenuation coefficients of the second solidified layer, the first solidified layer and the copper foil to X-rays and β-rays.

8. The method for using the thickness measuring device for a double-layer coated sheet according to claim 7, characterized in that: The following steps are also included: SS1, adjusting the pumping power of the first booster pump (21) and the second booster pump (23) until the first booster pump (21) reaches a preset speed V1 and the second booster pump (23) reaches a preset speed V2, and setting V2 equal to 0; then, maintaining the pumping power of the first booster pump (21) and the second booster pump (23); then, sequentially executing steps S1 to S3, and recording the data fed back by the X-ray thickness gauge (6), the data fed back by the X-ray detector (13), and the data fed back by the β-ray generator (15); SS2, maintaining the pumping power V1 of the first booster pump (21) unchanged, repeatedly and gradually adjusting the pumping power V2' of the second booster pump (23), maintaining the adjusted pumping power V2' of the second booster pump (23) stable after each adjustment, and executing steps S1 to S3 again, and recording the data fed back by the X-ray thickness gauge (6), the data fed back by the X-ray detector (13), and the data fed back by the β-ray generator (15); SS3, calculate according to the data obtained in step SS1 and step SS2 and ; then according to The K value is calculated, and then the copper foils carrying the second cured layer and the first cured layer are cut and compared with the measured value to obtain the relational expression 5.

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