A thickness measuring device for a double-coated sheet and a method of use

Abstract

The present application relates to a kind of double-layer coated sheet thickness measuring device and method for using, including double-layer coating die and drying device, double-layer coating die includes upper die, middle die, lower die, first material conveying channel and second material conveying channel, coating component one side is equipped with X-ray thickness gauge, drying device one side is equipped with dual-energy ray thickness gauge, dual-energy ray thickness gauge includes rack, first upper slide rail, first lower slide rail, first sliding block, X-ray generator, second sliding block, X-ray detector, beta ray detector, beta ray generator, first deflection roller and second deflection roller;Double-layer coating die one side is equipped with back roll, back roll is equipped with rotary encoder, first material conveying channel is equipped with first conveying pipe, first conveying pipe is equipped with first booster pump, second material conveying channel is equipped with second conveying pipe, second conveying pipe is equipped with second booster pump.Can feedback double-layer coated pole piece area density and carbon element and silicon element proportion.The present application is convenient to use, with wide market prospect.

Description

Technical Field

[0001] This invention relates to the field of thickness measuring equipment for double-coated sheets, and more specifically to a thickness measuring device and method for using double-coated sheets. Background Technology

[0002] Double-layer coating technology, as an advanced electrode fabrication process, holds great potential for improving lithium-ion battery performance. The design of the binder's layered structure is a key aspect of this process, significantly impacting the electrode's structural integrity, cycle stability, and electrochemical performance. Double-layer coating involves coating two slurries with different properties onto a current collector to form a double-layer electrode structure. This process allows for targeted design and optimization of the different electrode layers to meet various requirements.

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

[0004] The technology mentioned in this document specifically involves two types of slurries: a carbon black-containing slurry as the base layer and a silicon-containing slurry coated on top of the base layer. During the production process, when simultaneously coating both slurries, the liquid supply ratio of the two slurries should be fed back in a timely manner to meet the technical requirements for double-layer coated electrode production. However, existing technologies lack corresponding technical means for controlling the liquid supply ratio of the two slurries during simultaneous coating, thus providing room for improvement. This involves measuring the ratio between carbon and silicon elements to provide feedback on the liquid supply ratio of the two slurries. This allows for timely adjustment of the liquid supply ratio of the two slurries based on the areal density data, thereby improving the electrode yield. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a thickness measurement device and method for a double-layer coated sheet capable of providing feedback on the surface density and carbon-to-silicon ratio of the negative electrode sheet of a lithium battery, thereby overcoming the deficiencies in existing technologies.

[0006] The technical solution adopted in this invention is as follows: a thickness measuring device for double-layer coated sheets, comprising a double-layer coating die and a drying device. The double-layer coating die includes an upper die, a middle die, a lower die, a first feeding channel on the lower die, and a second feeding channel on the upper die. An X-ray thickness gauge is disposed on the side of the double-layer coating die away from the drying device, and a dual-energy X-ray thickness gauge is disposed on the side of the drying device away from the double-layer coating die. The dual-energy X-ray thickness gauge includes a frame, a first upper slide rail disposed on the frame, a first lower slide rail disposed below the first upper slide rail, a first slider disposed on the first upper slide rail, and an X-ray tube disposed on the side of the first slider facing the first lower slide rail. The device comprises an X-ray generator, a second slider mounted on a first sliding rail, an X-ray detector mounted on the side of the second slider facing the X-ray generator, a β-ray detector mounted on one side of the X-ray detector, a β-ray generator mounted above the β-ray detector, a first steering roller mounted on the side of the β-ray detector away from the X-ray detector, and a second steering roller mounted on the side of the X-ray detector away from the β-ray detector; a back roller is mounted on one side of the double-layer coating die head, a rotary encoder is mounted on the back roller, a first conveying pipe is mounted on the first conveying channel, a first booster pump is mounted on the first conveying pipe, a second conveying pipe is mounted on the second conveying channel, and a second booster pump is mounted on the second conveying pipe.

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

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

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

[0010] Preferably, the first and second steering rollers 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 end of the first steering roller, and the top end of the second steering roller are located on the same plane.

[0011] A method of using the thickness measuring device for a double-coated sheet as described above includes the following steps: S1. Mark the non-coated 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 performs continuous thickness measurement. The copper foil after the thickness measurement by the X-ray thickness gauge is continuously conveyed to the bottom of the double-layer coating die head. The first slurry enters the first conveying pipe, is pressurized by the first booster pump, and then enters the first material conveying channel. It passes through the gap between the middle die and the lower die and is coated on the copper foil to form the first coating layer. At the same time, the second slurry enters the second conveying channel after being pressurized by the second booster pump through the second conveying pipe and passes through the gap between the upper die and the middle die to be coated on the top of the first coating layer to form the second coating layer. S2. The copper foil loads the first coating layer and the second coating layer and are continuously fed into the drying device for curing. After curing, the first coating layer forms a first cured layer and the second coating layer forms a second cured layer. S3. After the copper foil carrying the first and second cured layers is guided by the second steering roller, the parameters fed back by the rotary encoder on the back roller, combined with the time it takes for the uncoated area at the edge of the copper foil to reach the gap between the X-ray generator and the X-ray detector, cause the X-ray generator and the X-ray detector to reciprocate linearly along a direction parallel to the first upper slide rail. Again, using the parameters fed back by the rotary encoder on the back roller, combined with the time it takes for the uncoated area at the edge of the copper foil to reach the gap between the X-ray β-ray detector and the β-ray generator, the β-ray detector and the β-ray generator reciprocate linearly along a direction parallel to the first upper slide rail. The copper foil carrying the first and second cured layers is then guided downstream through the gap between the X-ray generator and the X-ray detector, the gap between the β-ray detector and the β-ray generator, and the first steering roller. In step S3, the X-ray generator performs linear reciprocating motion. The X-ray generator and X-ray detector, as well as the β-ray detector and β-ray generator, all perform repeated synchronous linear reciprocating motions. During this process, the X-ray generator is always positioned above the X-ray detector, and the β-ray generator is always positioned above the β-ray detector. The moving speed of the X-ray generator and the moving speed of the β-ray generator are equal. 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 [missing information]. ; The aforementioned ,in The rotational speed parameter is calculated based on the parameters fed back from the rotary encoder. R is the circumference of the back roller, and R is the radius of the back roller; It 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 the direction perpendicular to the extension of the first upper slide rail; The time interval between the beta-ray detector and the X-ray detector feeding back data from the same point satisfies ; in, The rotational speed parameter is calculated based on the parameters fed back from the rotary encoder. The circumference of the second steering roller. Where is the radius of the back roller. It is the distance between the X-ray generator and the beta-ray generator along the direction perpendicular to the first upper slide rail.

[0012] Preferably, the X-rays emitted by the X-ray generator are absorbed sequentially by the second curing layer, the first curing layer, and the copper foil before being fed back by the X-ray detector. The attenuation law of the X-rays satisfies Equation 1. The first relational expression is: ; in, The measurement is performed to count the number of X-rays detected by the X-ray detector within a certain time interval, provided that the second cured layer, the first cured layer, and the copper foil shield the X-ray detector at the measurement location are present. The X-ray thickness gauge counts X-rays within a certain time interval at the measurement location where copper foil obstructs the view. The measurement is performed to count the X-rays within a certain time interval detected by the X-ray detector, where the second and first cured layers at the measurement location are obstructed. This refers to the count of X-rays detected by an X-ray detector within a certain time interval when there is no obstruction. The mass attenuation coefficient (cm² / g) of the electrode for X-rays. The areal density of the electrode (g / cm³) It refers to the thickness of the electrode sheet; The beta rays emitted by the beta ray generator are absorbed sequentially by the second curing layer, the first curing layer, and the copper foil, and then fed back by the beta ray detector. The attenuation law of the beta rays satisfies Equation 2. The second relation is: ; in, The measurement is performed to count the number of beta rays detected by the beta ray detector within a certain time interval, provided that the second cured layer, the first cured layer, and the copper foil shield the beta ray detector at the measurement location are present. The beta ray count that the beta ray detector can measure when the beta ray is projected only onto the copper foil at the measurement location, based on the beta ray density parameter of the copper foil fed back by the X-ray thickness gauge. The second curing layer and the first curing layer block beta rays detected by the beta ray detector within a certain time interval. This refers to the beta rays detected by the beta ray detector within a certain time interval when there is no obstruction. The mass attenuation coefficient (cm² / g) of the electrode for β-rays. The areal density of the electrode (g / cm³) It refers to the thickness of the electrode sheet; Assume that the mass fraction of elements with high atomic numbers in the tested electrode is . Then the mass fraction of elements with lower atomic numbers is According to the calculation rules for the mass attenuation coefficient of composite materials, the mass attenuation coefficient of the electrode for X-rays... The following relationship three should be satisfied. The third relation is... in, This represents the mass attenuation coefficient of high atomic number elements in the electrode for X-rays. The mass attenuation coefficient of low atomic number elements in the electrode for X-rays is given. Furthermore, the mass attenuation coefficients of the second curing layer, the first curing layer, and the copper foil for low-energy X-rays increase with the increase of high atomic number elements in these layers. Therefore, taking the logarithm of Equation 1 and Equation 2 respectively, and substituting Equation 3, we obtain Equation 4 after simplification. The fourth relation is... ; Let the silicon-to-carbon ratio in the second cured layer, the first cured layer, and the copper foil be defined as... , and have Thus, we obtain relation five: The fifth relation is... ; in ; ; ; A is the slope coefficient, and B is the intercept coefficient. They are related to the mass attenuation coefficient of X-rays and the mass attenuation coefficient of β-rays for 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 curing layer, the first curing layer, and the copper foil for X-rays and β-rays.

[0013] Preferably, the following steps are also included: SS1. Adjust the rotational speeds of the first booster pump and the second booster pump until the first booster pump reaches a preset rotational speed V1 and the second booster pump reaches a preset rotational speed V2, then set V2 to 0; then, maintain the rotational speeds of the first booster pump and the second booster pump; then, execute steps S1 to S3 sequentially, and record 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; SS2. Keep the speed V1 of the first booster pump constant, and repeatedly and gradually adjust the speed V2' of the second booster pump. After each adjustment of the speed V2' of the second booster pump, keep the adjusted speed V2' of the second booster pump stable, and execute steps S1 to S3 again, and record the data fed back by the X-ray thickness gauge, the X-ray detector, and the β-ray generator again. SS3. Calculate based on the data obtained in steps SS1 and SS2. and Then according to The K value is calculated, and then the measured value is compared by cutting the copper foil of the second curing layer and the first curing layer to obtain the relationship formula five.

[0014] The beneficial effects of this invention are as follows: By comparing the actual weight with the calculated weight, it can be seen that Equation 5 has high reliability and stability, and can accurately predict the coating quality under different upper-layer pumping speeds. The error is within the experimentally permissible range, supporting the application of Equation 5 in actual production. Thus, based on the feedback of the negative electrode surface density of the lithium battery, Equation 5 is used to further feedback the ratio of carbon and silicon elements in the negative electrode sheet.

[0015] This invention features a simple structure, convenient operation, and ingenious design, which greatly improves work efficiency and has significant social and economic benefits. It is a product that is easy to promote and use. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention.

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

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

[0019] Figure 4 This is a schematic diagram of the dual-energy X-ray thickness gauge of the present invention. Detailed Implementation

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

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

[0022] The first steering roller 16 and the second steering roller 17 are both horizontally mounted on the frame 7. 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 on the same plane.

[0023] The instructions for using this product are as follows: Figure 1 and Figure 2 As shown, it includes the following steps: S1. Mark the non-coated 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 transported to the bottom of the double-layer coating die head. The first slurry enters the first conveying pipe 20, is pressurized by the first booster pump 21, and enters the first material conveying channel 4. It is coated on the copper foil through the gap between the middle die 2 and the lower die 3 to form the first coating layer. At the same time, the second slurry enters the second material conveying channel 5 through the second conveying pipe 22 and is pressurized by the second booster pump 23. It is coated on the top of the first coating layer through the gap between the upper die 1 and the middle die 2 to form the second coating layer. S2. The copper foil loads the first coating layer and the second coating layer and are continuously fed into the drying device for curing. After curing, the first coating layer forms a first cured layer and the second coating layer forms a second cured layer. S3. After the copper foil carrying the first cured layer and the second cured layer is guided by the second steering roller 17, the parameters fed back by the rotary encoder 19 on the back roller 18, combined with the time it takes for the marked area of ​​the uncoated region at the edge of the copper foil to reach the gap area between the X-ray generator 11 and the X-ray detector 13, cause the X-ray generator 11 and the X-ray detector 13 to reciprocate linearly along a direction parallel to the first upper slide rail 8. Again, using the parameters fed back by the rotary encoder 19 on the back roller 18, combined with the time it takes for the marked area of ​​the uncoated region at the edge of the copper foil to reach the gap area between the X-ray β-ray detector 14 and the β-ray generator 15, the β-ray detector 14 and the β-ray generator 15 reciprocate linearly along a direction parallel to the first upper slide rail 8. The copper foil carrying the first cured layer and the second cured layer is guided sequentially 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 before being sent downstream. In step S3, the X-ray generator 11 performs linear reciprocating motion. The X-ray generator 11 and X-ray detector 13, as well as the β-ray detector 14 and β-ray generator 15, all perform repeated synchronous linear reciprocating motions. During this process, the X-ray generator 11 is always positioned above the X-ray detector 13, and the β-ray generator 15 is always positioned above the β-ray detector 14. The moving speed of the X-ray generator 11 and the moving speed of the β-ray generator 15 are equal. The distance between the X-ray generator 11 and the β-ray generator 15 along the direction parallel to the first upper slide rail 8 is always... ; The aforementioned ,in The rotational speed parameter is calculated based on the parameters fed back from the rotary encoder 19. R is the circumference of the back roller 18, and R is the radius of the back roller 18; It 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 the direction perpendicular to the extension of the first upper slide rail 8; The time interval between the β-ray detector 14 and the X-ray detector 13 feeding back data from the same point satisfies ; in, The rotational speed parameter is calculated based on the parameters fed back from the rotary encoder 19. The circumference of the second steering roller 17, The radius of the back roller 18, The distance between the X-ray generator 11 and the beta-ray generator 15 along the direction perpendicular to the first upper slide rail 8.

[0024] Furthermore, the X-rays emitted by the X-ray generator 11 are absorbed sequentially by the second curing layer, the first curing layer, and the copper foil before being fed back by the X-ray detector 13. The attenuation law of the X-rays satisfies Equation 1. The first relational expression is: ; in, The measurement is performed to count the X-rays detected by the X-ray detector 13 within a certain time interval, where the second cured layer, the first cured layer, and the copper foil shielding the X-ray detector 13 are present at the measurement location. The X-ray thickness gauge 6 counts X-rays within a certain time interval measured at a location where copper foil obstructs the measurement. The measurement is performed to count the X-rays detected by the X-ray detector 13 within a certain time interval, where the second cured layer and the first cured layer are present at the measurement location. This is the count of X-rays detected by X-ray detector 13 within a certain time interval when there is no obstruction. The mass attenuation coefficient (cm² / g) of the electrode for X-rays. The areal density of the electrode (g / cm³) It refers to the thickness of the electrode sheet.

[0025] The beta rays emitted by the beta ray generator 15 are absorbed sequentially by the second curing layer, the first curing layer, and the copper foil, and then fed back by the beta ray detector 14. The attenuation law of the beta rays satisfies Equation 2. The second relation is: ; in, The measurement is performed to count the number of beta rays detected by the beta ray detector 14 within a certain time interval, in the presence of the second cured layer, the first cured layer, and the copper foil shielding the beta ray detector 14 at the measurement location. The beta ray count that the beta ray detector 14 can measure when the beta ray is projected only onto the copper foil at the measurement location, based on the beta ray density parameter of the copper foil fed back by the X-ray thickness gauge 6. The second curing layer and the first curing layer block the beta rays detected by the beta ray detector 14 within a certain time interval. The beta rays detected by beta ray detector 14 within a certain time interval when there is no obstruction. The mass attenuation coefficient (cm² / g) of the electrode for β-rays. The areal density of the electrode (g / cm³) It refers to the thickness of the electrode sheet; Assume that the mass fraction of elements with high atomic numbers in the tested electrode is . Then the mass fraction of elements with lower atomic numbers is According to the calculation rules for the mass attenuation coefficient of composite materials, the mass attenuation coefficient of the electrode for X-rays... The following relationship three should be satisfied. The third relation is... in, This represents the mass attenuation coefficient of high atomic number elements in the electrode for X-rays. The mass attenuation coefficient of low atomic number elements in the electrode for X-rays is given. Furthermore, the mass attenuation coefficients of the second curing layer, the first curing layer, and the copper foil for low-energy X-rays increase with the increase of high atomic number elements in these layers. Therefore, taking the logarithm of Equation 1 and Equation 2 respectively, and substituting Equation 3, we obtain Equation 4 after simplification. The fourth relation is... ; Let the silicon-to-carbon ratio in the second cured layer, the first cured layer, and the copper foil be defined as... , and have Thus, we obtain relation five: The fifth relation is... ; in ; ; ; A is the slope coefficient, and B is the intercept coefficient. They are related to the mass attenuation coefficient of X-rays and the mass attenuation coefficient of β-rays for 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 curing layer, the first curing layer, and the copper foil for X-rays and β-rays.

[0026] When the product performs continuous online measurement on the copper foil with the second and first curing layers attached using Equation 5, it is necessary to obtain the actual measurement data. and ; and then according to The K value is calculated, thereby enabling the calibration of the measured data of the second curing layer, the first curing layer, and the copper foil using the aforementioned relationship five. Specifically, this includes the following steps: SS1. Adjust the rotational speeds of the first booster pump 21 and the second booster pump 23 until the first booster pump 21 reaches a preset rotational speed V1 and the second booster pump 23 reaches a preset rotational speed V2, then set V2 equal to 0; then, maintain the rotational speeds of the first booster pump 21 and the second booster pump 23; then, execute steps S1 to S3 sequentially, and record the data fed back by the X-ray thickness gauge 6, the X-ray detector 13, and the β-ray generator 15, convert them into weight, and obtain Table 1, as shown below: SS2. Keeping the rotational speed V1 of the first booster pump 21 constant, the rotational speed V2' of the second booster pump 23 is gradually adjusted repeatedly. After each adjustment of the rotational speed V2' of the second booster pump 23, the adjusted rotational speed V2' is kept stable. Steps S1 to S3 are executed again, and the data fed back by the X-ray thickness gauge 6, the X-ray detector 13, and the β-ray generator 15 are recorded again. The data fed back by the X-ray thickness gauge 1, the X-ray detector 13, and the β-ray generator 15 are then converted into weight and the results are shown in Table 2 below. The net weight of the second coating layer and its proportion in the total coating weight composed of the first and second cured layers are obtained by subtracting the net weight of the first coating layer formed using only the first coating layer formed using the preset speed V1 of the first booster pump 21 from the net weight after changing the preset speed V2' of the second booster pump 23. The calculation results are shown in Table 3. SS3. Calculate based on the data obtained in steps SS1 and SS2. and Then according to The K value was calculated as shown in Table 4. Then, by cutting the copper foil of the second curing layer and the first curing layer and comparing it with the measured value, the relationship formula 5 was obtained.

[0027] Having obtained the actual silicon-to-carbon ratio and the value of K, we can derive their relationship using the least squares method. After determining the silicon-to-carbon ratio formula, we simultaneously vary the rotational speed V3 of the first booster pump 21 and the rotational speed V4 of the second booster pump 23, setting V3=V4, to calculate the silicon-to-carbon ratio and thus deduce the theoretical weight of the upper layer. The calculated results are compared with the actual weight when only the upper layer is coated to verify the accuracy of the formula, as shown in Table 5. The silicon-to-carbon ratio calculated using Equation 5 and the estimated weight of the upper layer are shown in Table 6: Adjust the rotational speed V5 of the first booster pump 21 to zero, and fine-tune the rotational speed V6 of the second booster pump 23, and set V6=V3. Repeat steps S1 to S3 to coat the product and measure it using the gravimetric method, as shown in Table 7. Then, use relation five 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 obtained by measuring using the gravimetric method, as shown in Table 8.

[0028] Based on the information in Table 8, the error range between the calculated upper layer weight and the actual upper layer weight using Equation 5 was obtained, including an absolute error of +0.29g to +0.59g and a relative error of -0.52% to +0.73%. The relative errors were all controlled within 1%, indicating that the deviation between the calculated and actual values ​​was very small, meeting the experimental accuracy requirements. The deviation distribution in Table 8 showed that the calculated values ​​for groups 1, 2, and 5 were slightly lower than the actual values, possibly related to minor fluctuations in the upper layer pump speed during the experiment. Overall, the deviations showed no obvious systematic trend, verifying the applicability of Equation 5.

[0029] Through Example 1, by comparing the actual weight with the calculated weight, it can be seen that Relation 5 has high reliability and stability, and can accurately predict the coating quality under different upper-layer pumping speeds. The error is within the experimentally permissible range, supporting the application of Relation 5 in actual production. Thus, based on the feedback of the negative electrode sheet surface density of the lithium battery, Relation 5 is used to further feedback the ratio of carbon and silicon elements in the negative electrode sheet.

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

[0031] Unlike step S3 in Example 1, Example 2 uses step S3. 、 Instead of step S3 in Example 1, the other steps remain the same, while the specific step S3... 、 The copper foil carrying the first cured layer and the second cured layer are guided by the second steering roller 17 and then 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 11 before being sent downstream. In step S3, the X-ray generator 11 performs a linear reciprocating motion. The X-ray detector 13, β-ray detector 14, and β-ray generator 15 all perform repeated synchronous linear reciprocating motions accompanying the X-ray generator 11. During this process, the X-ray generator 11 is always positioned above the X-ray detector 13, and the β-ray generator 15 is always positioned above the β-ray detector 14. The linear reciprocating motion includes one forward movement and one reverse movement. Data acquisition by the X-ray detector 13 and β-ray detector 14 is only performed during the forward movement. When performing the reverse movement within the linear reciprocating motion, the corresponding first linear motor 24 performs the reverse movement at maximum power, quickly resetting the device. The distance between the X-ray generator 11 and the β-ray generator 15 along the 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, which in turn drives the first synchronous pulley 34 and the second synchronous pulley 35 to rotate, thereby driving the second synchronous belt 39 and the first synchronous belt 38 to move, which in turn drives the first slider 10 and the second slider 12 to move synchronously, thereby driving the X-ray generator 11, X-ray detector 13, β-ray detector 14, and 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 to Example 1, Example 2 reduces system error and improves the accuracy of feedback from X-ray detector 13 and β-ray detector 14 at the same measurement point.

[0034] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of the present invention should be included within the scope of the present invention.

Claims

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

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

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

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

5. The thickness measuring device for double-layer coated sheets 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 on the same plane.

6. A method of using the thickness measuring device for a double-coated sheet as described in claim 1, characterized in that, Includes the following steps, S1. Mark the non-coated 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. After the thickness measurement by the X-ray thickness gauge (6), the copper foil is continuously transported to the bottom of the double-layer coating die head. The first slurry enters the first conveying pipe (20), is pressurized by the first booster pump (21), and enters the first material conveying channel (4). It passes through the gap between the middle die (2) and the lower die (3) and is coated on the copper foil to form the first coating layer. At the same time, the second slurry enters the second material conveying channel (5) after being pressurized by the second booster pump (23) through the second conveying pipe (22). It passes through the gap between the upper die (1) and the middle die (2) and is coated on the top of the first coating layer to form the second coating layer. S2. The copper foil loads the first coating layer and the second coating layer and are continuously fed into the drying device for curing. After curing, the first coating layer forms a first cured layer and the second coating layer forms a second cured layer. S3. After the copper foil carrying the first cured layer and the second cured layer is 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 it takes for the marked area of ​​the uncoated area at the edge of the copper foil to reach the gap area between the X-ray generator (11) and the X-ray detector (13). The X-ray generator (11) and the X-ray detector (13) reciprocate linearly along a direction parallel to the first upper slide rail (8). Again, the parameters fed back by the rotary encoder (19) on the back roller (18) are combined with the time it takes for the copper foil to reach the gap area between the X-ray generator (11) and the X-ray detector (13). The time it takes for the mark of the uncoated area at the edge of the foil to reach 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) reciprocate linearly along a direction parallel to the first upper slide rail (8); the copper foil carrying the first cured layer and the second cured layer passes sequentially 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 before being sent downstream; In step S3, the X-ray generator (11) performs linear reciprocating motion. The X-ray generator (11), X-ray detector (13), β-ray detector (14), and β-ray generator (15) all perform repeated synchronous linear reciprocating motions. During this process, the X-ray generator (11) is always above the X-ray detector (13), and the β-ray generator (15) is always above the β-ray detector (14). The moving speed of the X-ray generator (11) and the moving speed of the β-ray generator (15) are equal. The distance between the X-ray generator (11) and the β-ray generator (15) along the direction parallel to the first upper slide rail (8) is always... ; The aforementioned ,in The rotational speed parameter is calculated based on the parameters fed back from the rotary encoder (19). R is the circumference of the back roller (18), and R is the radius of the back roller (18); It 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 the direction perpendicular to the first upper slide rail (8); The time interval between the β-ray detector (14) and the X-ray detector (13) feeding back data from the same point satisfies ; in, The rotational speed parameter is calculated based on the parameters fed back from the rotary encoder (19). The circumference of the second steering roller (17) is... The radius of the back roller (18) is... The distance between the X-ray generator (11) and the beta-ray generator (15) along the direction perpendicular to the first upper slide rail (8).

7. The method of using the thickness measuring device for double-layer coated sheets according to claim 6, characterized in that, The X-rays emitted by the X-ray generator (11) are absorbed sequentially by the second curing layer, the first curing layer, and the copper foil, and then fed back by the X-ray detector (13). The attenuation law of the X-rays satisfies Equation 1. The first relational expression is: ; in, To measure the count of X-rays detected by the X-ray detector (13) within a certain time interval at the location where the second cured layer, the first cured layer, and the copper foil shielding exist, The X-ray thickness gauge (6) counts X-rays within a certain time interval measured by the X-ray thickness gauge when there is copper foil obstruction at the measurement location. The measurement is performed to count the X-rays detected by the X-ray detector (13) within a certain time interval, where the second curing layer and the first curing layer at the measurement location are present. This is the count of X-rays detected by the X-ray detector (13) within a certain time interval when there is no obstruction. The mass attenuation coefficient (cm² / g) of the electrode for X-rays. The areal density of the electrode (g / cm³) It refers to the thickness of the electrode sheet; The beta rays emitted by the beta ray generator (15) are absorbed sequentially by the second curing layer, the first curing layer, and the copper foil, and then fed back by the beta ray detector (14). The attenuation law of the beta rays satisfies Equation 2. The second relation is: ; in, To measure the count of β rays detected by the β-ray detector (14) within a certain time interval at the location where the second curing layer, the first curing layer, and the copper foil shielding are present, The β-ray count that the β-ray detector (14) can measure when the β-ray is only projected onto the copper foil at the measurement location, based on the copper foil surface density parameter fed back by the X-ray thickness gauge (6). The second curing layer and the first curing layer shield the β rays detected by the β-ray detector (14) within a certain time interval. The beta rays detected by the beta ray detector (14) within a certain time interval when there is no obstruction. The mass attenuation coefficient (cm² / g) of the electrode for β-rays. The areal density of the electrode (g / cm³) It refers to the thickness of the electrode sheet; Assume that the mass fraction of elements with high atomic numbers in the tested electrode is . Then the mass fraction of elements with lower atomic numbers is According to the calculation rules for the mass attenuation coefficient of composite materials, the mass attenuation coefficient of the electrode for X-rays... The following relationship three should be satisfied. The third relation is... in, This represents the mass attenuation coefficient of high atomic number elements in the electrode for X-rays. The mass attenuation coefficient of low atomic number elements in the electrode for X-rays is given. Furthermore, the mass attenuation coefficients of the second curing layer, the first curing layer, and the copper foil for low-energy X-rays increase with the increase of high atomic number elements in these layers. Therefore, taking the logarithm of Equation 1 and Equation 2 respectively, and substituting Equation 3, we obtain Equation 4 after simplification. The fourth relation is... ; Let the silicon-to-carbon ratio in the second cured layer, the first cured layer, and the copper foil be defined as... , and have Thus, we obtain relation five: The fifth relation is... = ; in ; ; ; A is the slope coefficient, and B is the intercept coefficient. They are related to the mass attenuation coefficient of X-rays and the mass attenuation coefficient of β-rays for 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 curing layer, the first curing layer, and the copper foil for X-rays and β-rays.

8. The method of using the thickness measuring device for double-layer coated sheets according to claim 7, characterized in that, It also includes the following steps: SS1. Adjust the pumping power of the first booster pump (21) and the second booster pump (23) until the first booster pump (21) reaches the preset speed V1 and the preset speed of the second booster pump (23) is V2, and set V2 equal to 0; then, maintain the pumping power of the first booster pump (21) and the second booster pump (23); then, execute 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); SS2. Keep the pumping power V1 of the first booster pump (21) unchanged, and repeatedly adjust the pumping power V2` of the second booster pump (23) step by step. After each adjustment of the pumping power V2` of the second booster pump (23), keep the pumping power V2` of the second booster pump (23) stable after 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. SS3. Calculate based on the data obtained in steps SS1 and SS2. and Then according to The K value is calculated, and then the measured value is compared by cutting the copper foil of the second curing layer and the first curing layer to obtain the relationship formula five.

Images