Pole piece rebound thickness control method and pole piece rebound thickness control system

Abstract

The invention relates to the technical field of batteries, in particular to a pole piece rebound thickness control method and a pole piece rebound thickness control system. The pole piece rebound thickness control method comprises the following steps: carrying out first thickness detection on a rolled pole piece to obtain first thickness data; transferring the pole piece into a standing warehouse, and standing for a first preset time; transferring the pole piece from the standing warehouse to a detection station to carry out second thickness detection so as to obtain second thickness data; processing the first thickness data and the second thickness data to obtain third thickness data; comparing the third thickness data with an ex-warehouse standard, and if the third thickness data meets the ex-warehouse standard, transferring the pole piece to a starting position of a next process; and if the third thickness data does not conform to the ex-warehouse standard, returning the pole piece to the standing warehouse, and standing for a second preset time.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a pole piece rebound thickness control method and a pole piece rebound thickness control system. Background Art

[0002] The pole piece is an important component of lithium-ion batteries. In the battery production process, the pole piece usually needs to be allowed to rest and rebound for a period of time after rolling to ensure that the thickness of the pole piece tends to be consistent. If the pole piece rebound thickness is insufficient, the pole piece is prone to misalignment during subsequent winding, which in turn affects the processing and production of the battery. At the same time, insufficient pole piece rebound thickness will also affect the pole piece wetting effect and long-term cycle performance, which will directly affect the performance and service life of the battery.

[0003] In the existing production process, there is still a lack of detection and control methods for the thickness of the electrode after standing still. This easily leads to the electrode with rebound thickness that does not meet the standard after standing still entering the subsequent processing steps of the battery, thereby affecting the subsequent processing of the battery and the performance and life of the finished battery. Summary of the invention

[0004] In view of the above, an embodiment of the present invention proposes a pole piece rebound thickness control method and a pole piece rebound thickness control system to at least solve the technical problems existing in the above-mentioned prior art.

[0005] The method for controlling the rebound thickness of a pole piece according to an embodiment of the present invention comprises:

[0006] Performing a first thickness test on the rolled pole piece to obtain first thickness data;

[0007] Transferring the pole piece to a static storage and allowing it to stand for a first predetermined time;

[0008] Transferring the pole piece from the static storage to a testing station for a second thickness test to obtain second thickness data;

[0009] Processing the first thickness data and the second thickness data to obtain third thickness data;

[0010] The third thickness data is compared with the outgoing standard. If the third thickness data meets the outgoing standard, the pole piece is transferred to the starting position of the next process; if the third thickness data does not meet the outgoing standard, the pole piece is returned to the static warehouse and placed for a second predetermined time.

[0011] Optionally, the transferring of the pole piece from the static storage to a testing station for a second thickness test to obtain second thickness data comprises:

[0012] The second thickness detection is performed on the pole piece by an X-ray thickness detection device.

[0013] Optionally, the second thickness detection of the pole piece by an X-ray thickness detection device includes:

[0014] Using the X-ray tube of the X-ray thickness detection device to penetrate and irradiate the pole piece along the tangent direction of the pole piece;

[0015] The flat panel detector of the X-ray thickness detection device receives the X-ray after penetrating the pole piece and generates a grayscale image having the second thickness data.

[0016] Optionally, the method further comprises:

[0017] When the first thickness data of the pole piece is obtained, a film roll number corresponding to the pole piece is synchronously generated, and a production database associating the film roll number with the first thickness data is established.

[0018] Optionally, the step of transferring the pole piece to a static storage and placing the pole piece therein for a first predetermined time comprises:

[0019] Recording the time when the electrode enters the static storage and the film roll number;

[0020] Record the static time of the corresponding electrode in the static storage according to the film roll number;

[0021] According to the film roll number, the electrode pieces after being static for the first predetermined time are transferred out of the static storage in the order of the entry time.

[0022] Optionally, the method further comprises:

[0023] The next process starting position identifies the film roll number of the electrode;

[0024] The resting time of the electrode in the static warehouse is retrieved according to the film roll number of the electrode. If the resting time of the electrode in the static warehouse is less than the first predetermined time, the processing plan of the electrode in the next process is immediately terminated.

[0025] Optionally, the first predetermined time is 24 hours to 168 hours.

[0026] Optionally, the second predetermined time is 6 hours to 48 hours.

[0027] Optionally, the third thickness data is the ratio of a difference between the second thickness data and the first thickness data to the first thickness data.

[0028] Optionally, the lower limit value of the release standard is 2%-4%.

[0029] On the other hand, an embodiment of the present invention provides a pole piece rebound thickness control system, the pole piece rebound thickness control system of the present invention comprises a controller, a first thickness detection mechanism, a static storage, a second thickness detection mechanism and a conveying mechanism;

[0030] The first thickness detection mechanism is used to detect the first thickness data of the electrode piece after rolling; the static storage is used to let the electrode piece after rolling stand for a first predetermined time; the second thickness detection mechanism is used to detect the second thickness data of the electrode piece transferred from the static storage after standing; the conveying mechanism is used to transport the electrode piece;

[0031] The controller is used to process the first thickness data and the second thickness data to obtain third thickness data, and compare the third thickness data with the outgoing standard; if the third thickness data meets the outgoing standard, the pole piece is transferred to the starting position of the next process; if the third thickness data does not meet the outgoing standard, the pole piece is returned to the static warehouse and left to stand for a second predetermined time.

[0032] Compared with the prior art, the pole piece rebound thickness control method described in the embodiment of the present invention has the following advantages:

[0033] In the pole piece rebound thickness control method described in the embodiment of the present invention, by obtaining the first thickness data of the pole piece after rolling and the second thickness data after standing still, the thickness data of the pole piece after standing still can be strictly controlled. For pole pieces whose rebound thickness does not meet the requirements after standing still, they can be sent back to the standing still warehouse to be stood still again, so as to avoid the pole piece with insufficient rebound thickness being transferred to the next process and causing adverse effects on the next process. The above method strictly controls the thickness of the pole piece during the pole piece standing still warehouse stage, ensuring that the pole pieces entering the next process are pole pieces with thickness that meet the processing standards, which is beneficial to ensure the efficiency of subsequent processing and the yield rate of the final product. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0035] Figure 1 is a flow chart of a method for controlling the rebound thickness of a pole piece according to an embodiment of the present invention;

[0036] Figure 2 is a system device diagram of a pole piece rebound thickness control method according to an embodiment of the present invention;

[0037] Figure 3 It is a schematic diagram of the grayscale signal received on the flat panel detector;

[0038] Figure numerals: 1, pole piece; 2, static storage; 3, conveyor belt; 4, X-ray tube; 5, flat panel detector; 6, copper foil image A; 7, copper foil image B; 8, starting position of the next process. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] For existing lithium batteries, pole pieces are an extremely important component. Existing pole pieces generally include copper or aluminum foil and a coating applied on both sides of the current collector foil. The coating is generally prepared by mixing raw materials such as active materials, binders and conductive agents. The coating is applied on both sides of the current collector such as copper or aluminum, and after drying to remove the solvent, it forms a pole piece together with the foil.

[0041] After the electrode is coated and dried, the bonding strength between the coating and the foil is very low. Therefore, the electrode needs to be rolled after drying to enhance the bonding strength between the coating and the foil. This can prevent the coating from peeling off during the electrolyte immersion and battery use; it can also compress the battery cell volume, increase the battery cell energy density, reduce the porosity between the active material, conductive agent, and binder inside the electrode, reduce the resistance of the battery and improve the battery performance.

[0042] However, the pole pieces after rolling usually need to stand for a period of time to allow the thickness of the pole pieces to rebound to the allowable thickness. The thickness rebound amount of the same batch of pole pieces after standing is not the same, which means that there are certain differences in the thickness of the pole pieces entering the next winding process. If the pole piece with insufficient rebound thickness directly enters the next winding process, it will cause a large misalignment of the pole ear of the pole piece after winding, which will affect the subsequent pole ear welding. At the same time, the insufficient rebound thickness of the pole piece also means that the active materials on the pole piece are still in a compressed state. This will make it difficult for the pole piece to be completely soaked by the electrolyte, and the wetting effect of the pole piece is poor, which in turn affects the performance of the battery. Pole pieces with insufficient rebound thickness are prone to lithium precipitation during long-term use, which will seriously affect the long-term cycle performance of the battery, and directly affect the service life of the battery.

[0043] In the existing production process, there is still a lack of detection and control methods for the thickness of the electrode sheet after standing still. This easily leads to the rebound thickness of the electrode sheet after standing still, which in turn affects the subsequent processing of the battery and the performance and life of the finished battery. To this end, an embodiment of the present invention provides a method for controlling the rebound thickness of the electrode sheet, so as to strictly control the rebound thickness of the electrode sheet after standing still.

[0044] For reference Figure 1 As shown, the method described in the embodiment of the present invention at least includes the following steps:

[0045] S100: Performing a first thickness test on the rolled pole piece to obtain first thickness data.

[0046] In this step, a laser thickness gauge can be used to perform the first thickness detection on the pole piece after rolling. In order to ensure the accuracy of the data, the laser thickness gauge can perform thickness detection on the pole piece after rolling at multiple points to obtain thickness data of different parts of the pole piece after rolling. The first thickness data is the average of the thickness data of these different parts. It represents the average thickness of the pole piece after rolling and is also the basis for the subsequent calculation of the thickness rebound of the pole piece. The laser thickness gauge uploads the first thickness data to the controller, and the controller records and stores the first thickness data so that the first thickness data can be read and called at any time in the subsequent steps.

[0047] The laser thickness gauge can be integrated into the roller press to obtain the thickness of the pole piece after rolling in time. The roller press can use the existing pole piece rolling equipment. During production, the pole piece enters the roller press in a flat posture, and the two rollers of the roller press roll the pole piece from the upper and lower sides. The laser thickness gauge is set on the discharge side of the roller press, and the thickness of different parts of the pole piece output from the roller press is detected.

[0048] S200: transferring the pole piece to a static storage and placing it for a first predetermined time.

[0049] The pole piece after rolling is usually wound into a pole piece roll, mounted on a bracket, and transported to a designated static storage for static storage by a conveyor belt. After the pole piece is static for a first predetermined time, the controller controls the conveyor belt to transport the pole piece out of the storage.

[0050] S300: Transferring the pole piece from the static storage to a testing station for a second thickness test to obtain second thickness data.

[0051] In this step, the electrode piece after standing still is conveyed by the conveyor belt to the inspection station. The inspection station performs a second thickness inspection on the electrode piece through the thickness inspection device. The second thickness data obtained by the second thickness inspection is the current thickness of the electrode piece after standing still. The thickness inspection device uploads the second thickness data to the controller, and the controller records and stores the second thickness data so that the second thickness data can be read and called at any time in the subsequent steps.

[0052] S400: Processing the first thickness data and the second thickness data to obtain third thickness data;

[0053] S500: Compare the third thickness data with the delivery standard. If the third thickness data meets the delivery standard, execute:

[0054] S501: transferring the pole piece to the starting position of the next process;

[0055] If the third thickness data does not meet the release standard, execute:

[0056] S502: Return the pole piece to the static storage and place it for a second predetermined time.

[0057] In step S400, the controller combines the first thickness data and the second thickness data to calculate the third thickness data of the electrode. In step S500, the controller compares the third thickness data with the outbound standard. For the electrode whose third thickness data reaches the outbound standard, the controller executes step S501: the electrode is transported to the starting position of the next process by the conveyor belt and subsequent processing is carried out. For the electrode whose third thickness data does not reach the outbound standard, the controller executes step S502: the electrode is transported back to the static warehouse by the conveyor belt and is rested for a second predetermined time until the third thickness data of these electrode reaches the outbound standard, and then it is transported to the starting position of the next process. The above method strictly controls the rebound thickness of the electrode after standing, ensuring that the electrode entering the next process is a electrode whose thickness meets the processing standard, which is conducive to ensuring the efficiency of subsequent processing and the yield rate of the final product.

[0058] Optionally, for step S300: transferring the pole piece from the static storage to a detection station for a second thickness detection to obtain second thickness data, it may further include:

[0059] The pole piece is subjected to a second thickness inspection by an X-ray thickness inspection device.

[0060] In order to facilitate transportation, the pole piece is usually wound into a roll after rolling. This means that it is not easy for general thickness detection equipment to detect the thickness of the pole piece after winding. The X-ray thickness detection device can illuminate the pole piece after winding and obtain the internal grayscale image of the pole piece after winding. The density of the foil part is relatively large, such as copper foil, which has a density of 8.97 g / cm3, so the grayscale of the part corresponding to the foil in the internal grayscale image of the pole piece is relatively large. The density of the coating part is relatively small, generally 1.57 g / cm3, so the grayscale of the part corresponding to the coating in the internal grayscale image of the pole piece is relatively small. According to the grayscale image presented by the pole piece after irradiation with X-rays, the second thickness data of the pole piece can be obtained. This thickness detection method is simpler and more direct, easy to operate, and can directly and conveniently obtain the second thickness data of the rolled pole piece after standing.

[0061] The aforementioned second thickness detection of the electrode piece by the X-ray thickness detection device may specifically include:

[0062] Step S301: using an X-ray tube of an X-ray thickness detection device to penetrate and irradiate the pole piece along a tangential direction of the pole piece;

[0063] Step S302: using the flat panel detector of the X-ray thickness detection device to receive the X-rays that have penetrated the pole piece and generate corresponding grayscale signals, and then sending the grayscale signals to the controller.

[0064] In the embodiment of the present invention, the rolled electrode is usually placed on the conveyor belt in a horizontal posture for the convenience of transportation. In other words, during the transportation process, the electrode is placed on the conveyor belt in an axially horizontal arrangement. When the electrode arrives at the detection station, the X-ray tube of the X-ray thickness detection device can irradiate the rolled electrode from above the electrode along the tangential direction. The flat-panel detector of the X-ray thickness detection device is arranged below the electrode, receives the X-ray after penetrating the electrode and generates a corresponding grayscale signal, and then sends the grayscale signal to the controller. At this time, for the outermost part of the rolled electrode, it can be irradiated by X-rays vertically downward along its own tangential direction. Correspondingly, the flat-panel detector will also receive a strip-shaped grayscale signal. The strip with a larger grayscale is the thickness of the copper foil, and the strip with a smaller grayscale is the thickness of the coating. Since both sides of the copper foil have coatings, the distance between two adjacent strips with larger grayscale can be used as the second thickness data of the electrode. Such a measurement method can ensure the accuracy of the second thickness data, and is also convenient for value acquisition and reading. In addition, the flat panel detector can directly read the second thickness data and upload the second thickness data to the controller for recording and storage. This improves the intelligence level of the entire battery process and is conducive to improving the processing efficiency of the entire battery production process.

[0065] Optionally, the pole piece rebound thickness control method according to the embodiment of the present invention further includes:

[0066] Step A100: When the first thickness data of the pole piece is obtained, a film roll number corresponding to the pole piece is synchronously generated, and a production database associating the film roll number with the first thickness data is established.

[0067] Based on the film roll number, it is easier for the controller to track the status of each pole piece throughout the entire production process; based on the production database that associates the film roll number with the first thickness data, it is easier for the controller to know the first thickness data of each pole piece. After the second thickness detection of the pole piece, the controller can directly call the first thickness data of the pole piece based on the film roll number of the pole piece for comparison and processing. The setting of the film roll number improves the controller's ability to identify each pole piece, and further facilitates the controller's control of the pole piece during the production process.

[0068] Optionally, the aforementioned step of transferring the pole piece to a static storage and placing it in a static storage for a first predetermined time includes:

[0069] Step S201: recording the time when the electrode enters the static storage and the film roll number;

[0070] In this process, the film roll number can be attached to the corresponding electrode in the form of a QR code or barcode by a robot or manually. Correspondingly, a barcode scanner can be set at the entrance of the static warehouse. When the electrode enters the static warehouse, the barcode scanner automatically identifies the film roll number of the electrode and uploads it to the controller. The controller records the film roll number and the entry time of the electrode corresponding to the film roll number. The controller can also synchronously record the position of the electrode in the static warehouse, so as to drive the conveyor belt or the handling robot to automatically transport the electrode out of the warehouse.

[0071] Step S202: recording the static time of the corresponding electrode in the static storage according to the film roll number;

[0072] During this process, the controller automatically counts the static time of the electrode corresponding to each film roll number in the static warehouse. For the electrode whose static time reaches the first predetermined time, the controller can control the conveyor belt or the handling robot to transfer the electrode out of the warehouse.

[0073] Step S203: Controlling the electrode sheets after being static for the first predetermined time to be transferred out of the static storage in the order of the entry time according to the film roll number.

[0074] In this process, for the same batch of electrodes entering the warehouse, the controller can control the electrode to be transported out of the warehouse according to the principle of "first in, first out". In other words, for the electrode that enters the static warehouse first and whose static time reaches the first predetermined time, the controller can control the electrode to be transported out of the warehouse first. For the electrode that enters the static warehouse later and whose static time reaches the first predetermined time, the controller can control the electrode to be transported out of the warehouse later. In this way, the logic of entering and exiting the electrode in the static warehouse can be optimized, which is convenient for the controller to monitor and manage the electrode, and it can also prevent the electrode that has been static for the first predetermined time from staying in the static warehouse for too long.

[0075] Optionally, the pole piece rebound thickness control method according to the embodiment of the present invention further includes:

[0076] The film roll number of the electrode is identified at the start position of the next process;

[0077] The resting time of the electrode in the said resting warehouse is retrieved according to the film roll number of the electrode. If the resting time of the electrode in the resting warehouse is less than the first predetermined time, the processing plan of the electrode in the next process is immediately terminated.

[0078] In this process, a barcode scanner can be set at the start of the next process. When the electrode enters the start of the next process, the barcode scanner automatically identifies the film roll number of the electrode and uploads it to the controller, which queries the static time of the film roll number in the static warehouse. If the static time of the electrode in the static warehouse is less than the first predetermined time, the processing plan of the electrode in the next process is immediately terminated. This setting provides further protection for the subsequent production and processing process, and eliminates the possibility of the electrode with insufficient rebound thickness entering the subsequent process as much as possible.

[0079] Optionally, the first predetermined time is 24 hours to 168 hours. That is to say, for the pole piece that is left standing in the static warehouse after the first thickness test, the pole piece must be left standing in the static warehouse for 1 day to 7 days. If the standing time is less than one day, the thickness growth of the pole piece is limited and may not meet the requirements of the next process. If the standing time is greater than seven days, the thickness growth of the pole piece after seven days is almost negligible, and the benefit is minimal compared to the time cost. Therefore, the second predetermined time is 24 hours to 168 hours, which can ensure that the thickness of the pole piece after standing can meet the standard required by the next process as much as possible, while also avoiding meaningless time investment.

[0080] Optionally, the aforementioned second predetermined time is 6 hours to 48 hours. That is to say, for the electrode pieces whose third thickness data does not meet the delivery standards after the second thickness test, the controller will send the electrode pieces back to the static warehouse through the conveyor belt to be rested for 6 hours to 48 hours. If the resting time is less than 6 hours, the thickness growth of the electrode piece is limited, and it may still not meet the requirements of the next process. If the resting time is greater than 48 hours, the thickness growth of the electrode piece after 48 hours is also very limited, and the benefits are minimal compared to the time cost. Therefore, the second predetermined time is 6 hours to 48 hours, which can ensure that the thickness of the electrode piece after resting can meet the standards required for the next process as much as possible, while also avoiding meaningless time investment.

[0081] Optionally, the third thickness data is the ratio of the difference between the second thickness data and the first thickness data to the first thickness data. In other words, let the first thickness data be A, let the second thickness data be B, let the third thickness data be C, that is, C = (BA) / A * 100%. The third thickness data intuitively reflects the growth of the second thickness data compared to the first thickness data, so it is more convenient for the controller to screen the pole pieces that meet the outbound standards.

[0082] Optionally, the lower limit value of the aforementioned delivery standard is 2%-4%. That is, under normal circumstances, the third thickness data is greater than or equal to 2%, and the controller can determine that the thickness of the electrode after standing still meets the processing requirements of the next process. In a few cases, the lower limit value can be increased according to actual needs, such as 2.8%, 3.2%, etc. That is, the third thickness data is greater than or equal to 2.8% or 3.2%, and the controller can determine that the thickness of the electrode after standing still meets the processing requirements of the next process. The setting of this parameter can ensure that the electrode entering the next process are all electrode pieces that meet the minimum thickness requirements, thereby ensuring the processing efficiency and yield rate of the battery in the subsequent processing process.

[0083] The embodiment of the present invention also proposes a pole piece rebound thickness control system, which can be referred to Figure 2 As shown, the pole piece rebound thickness control system described in the embodiment of the present invention includes a controller, a first thickness detection mechanism, a static warehouse 2, a second thickness detection mechanism and a conveying mechanism;

[0084] The first thickness detection mechanism is used to detect the first thickness data of the electrode 1 after rolling; the static warehouse 2 is used to statically store the electrode 1 after rolling; the second thickness detection mechanism is used to detect the second thickness data of the electrode 1 transferred from the static warehouse 2 after static; the conveying mechanism is used to transport the electrode 1.

[0085] The controller is used to process the first thickness data and the second thickness data to obtain third thickness data, and compare the third thickness data with the outgoing standard; if the third thickness data meets the outgoing standard, the pole piece 1 is transferred to the starting position of the next process; if the third thickness data does not meet the outgoing standard, the pole piece 1 is returned to the static warehouse 2 and is placed for a second predetermined time.

[0086] For ease of understanding, the embodiments of the present invention further illustrate the pole piece rebound thickness control system of the present invention in conjunction with a specific production and processing process.

[0087] First, the pole piece 1 is put into the roller press for rolling, and the first thickness detection of the pole piece 1 after rolling is performed using a laser thickness gauge, and the first thickness data of the pole piece 1 after rolling is obtained. The laser thickness gauge is the first thickness detection mechanism, which can be integrated on the roller press so as to obtain the thickness of the pole piece 1 after rolling in time. The roller press can use the existing pole piece rolling equipment. During production, the pole piece 1 enters the roller press in a flat posture, and the two rollers of the roller press roll from the upper and lower surfaces of the pole piece 1. The laser thickness gauge is set on the discharge side of the roller press, and the thickness of different parts of the pole piece 1 output from the roller press is detected to obtain the thickness data of different parts on the pole piece 1 after rolling. The laser thickness gauge calculates the average of the thickness data of these different parts, and the average is the first thickness data. The first thickness data represents the average thickness of the pole piece 1 after rolling, and is also the basis for the subsequent calculation of the rebound amount of the pole piece thickness. The laser thickness measuring instrument uploads the first thickness data to the controller, and the controller records and stores the first thickness data so that the first thickness data can be read and called at any time in subsequent steps.

[0088] When the controller obtains the first thickness data of the pole piece 1, it synchronously generates the film roll number corresponding to the pole piece 1, and establishes a production database that associates the film roll number with the first thickness data. Based on the film roll number, it is easier for the controller to track the status of each pole piece 1 during the entire production process; based on the production database that associates the film roll number with the first thickness data, it is easier for the controller to know the first thickness data of each pole piece 1.

[0089] Secondly, the electrode 1 is transferred to the static storage 2 through the conveying mechanism and is placed in a static storage 2 for a first predetermined time. In the embodiment described in the present invention, the conveying mechanism generally uses a conveyor belt 3, and can also use a handling robot and other equipment. The electrode 1 after rolling is usually wound into a electrode roll, placed on a pallet, and transported to a designated static storage 2 by a conveyor belt 3 for static placement. After the electrode 1 is placed in a static state for the first predetermined time, the controller controls the conveyor belt 3 to transport the electrode 1 out of the static storage 2. The process specifically includes:

[0090] The controller records the entry time and film roll number of the electrode 1 into the static warehouse 2. In this process, the film roll number can be attached to the corresponding electrode 1 in the form of a QR code or a barcode by a robot or manually. Correspondingly, a barcode scanner can be set at the entrance of the static warehouse 2. When the electrode 1 enters the static warehouse 2, the barcode scanner automatically identifies the film roll number of the electrode 1 and uploads it to the controller, and the controller records the film roll number and the entry time of the electrode 1 corresponding to the film roll number. The controller can also synchronously record the position of the electrode 1 in the static warehouse 2, so as to drive the conveyor belt 3 or the handling robot to automatically transport the electrode 1 out of the warehouse.

[0091] The controller records the static time of the corresponding electrode 1 in the static warehouse 2 according to the film roll number. In this process, the controller automatically counts the static time of the electrode 1 corresponding to each film roll number in the static warehouse 2. For the electrode 1 whose static time reaches the first predetermined time, the controller can control the conveyor belt 3 or the handling robot to transfer the electrode 1 out of the warehouse.

[0092] The controller controls the electrode 1 to be transferred out of the static warehouse 2 according to the order of the entry time after being static for the first predetermined time according to the film roll number. In this process, for the same batch of electrode 1 entering the static warehouse 2, the controller can control the electrode 1 to be transported out of the static warehouse 2 according to the principle of "first in, first out". In other words, for the electrode 1 that enters the static warehouse 2 first and whose static time reaches the first predetermined time, the controller can control the electrode 1 to leave the static warehouse 2 first. For the electrode 1 that enters the static warehouse 2 later and whose static time reaches the first predetermined time, the controller can control the electrode 1 to leave the static warehouse 2 later. In this way, the entry and exit logic of the electrode 1 in the static warehouse 2 can be optimized, which makes it convenient for the controller to monitor and manage the electrode 1, and at the same time, it can also prevent the electrode 1 that has been static for the first predetermined time from staying in the static warehouse 2 for too long.

[0093] The first predetermined time is 24 hours to 168 hours. That is, for the pole piece 1 that is left in the static storage 2 after the first thickness detection, the pole piece 1 must be left in the static storage 2 for 1 day to 7 days.

[0094] Again, the electrode piece 1 after standing still is conveyed by the conveyor belt 3 to the inspection station; the inspection station performs a second thickness inspection on the electrode piece 1 through the second thickness inspection device. The second thickness data obtained by the second thickness inspection is the current thickness of the electrode piece 1 after standing still. The second thickness inspection device uploads the second thickness data to the controller, and the controller records and stores the second thickness data so that the second thickness data can be read and called at any time in the subsequent steps. This process can be specifically performed by performing a second thickness inspection on the electrode piece 1 through an X-ray thickness inspection device, that is, the second thickness inspection device is preferably an X-ray thickness inspection device. In order to facilitate transportation, the electrode piece 1 is usually wound into a roll after rolling. This means that it is not easy for general thickness inspection equipment to detect the thickness of the electrode piece 1 after winding. The X-ray thickness inspection device can illuminate the electrode piece 1 after winding and obtain the internal grayscale image of the electrode piece 1 after winding. The density of the foil part is relatively large, such as copper foil, which has a density of 8.97 g / cm3, so the grayscale of the corresponding part of the foil in the internal grayscale image of the electrode piece 1 is relatively large. The density of the coating part is relatively small, generally 1.57 g / cm3, so the grayscale of the part corresponding to the coating in the internal grayscale image of the electrode 1 is relatively small. According to the grayscale image presented by the electrode 1 after irradiation with X-rays, the second thickness data of the electrode 1 can be obtained. This process may specifically include:

[0095] Using an X-ray tube 4 of an X-ray thickness detection device to penetrate and irradiate the pole piece 1 along a tangential direction of the pole piece 1;

[0096] The flat panel detector 5 of the X-ray thickness detection device receives the X-ray after penetrating the pole piece 1 and generates a grayscale image having the second thickness data.

[0097] In the embodiment of the present invention, the rolled electrode 1 is usually placed on the conveyor belt 3 in a horizontal posture for the convenience of transportation. In other words, during the transportation process, the electrode 1 is placed on the conveyor belt 3 in an axially horizontal posture. When the electrode arrives at the detection station, the X-ray tube 4 of the X-ray thickness detection device can irradiate the rolled electrode 1 from above the electrode 1 along the tangential direction. The flat-panel detector 5 of the X-ray thickness detection device is arranged below the electrode 1, receives the X-ray after penetrating the electrode 1 and generates a corresponding grayscale signal, and then sends the grayscale signal to the controller. At this time, for the outermost circle of the rolled electrode 1, it can be irradiated by X-rays vertically downward along its own tangential direction. Correspondingly, the flat-panel detector 5 will also receive a grayscale signal in the form of a strip. The strip with a larger grayscale is the thickness of the copper foil, and the strip with a smaller grayscale is the thickness of the coating. Since there is a coating on both sides of the copper foil, the distance between two adjacent strips with a larger grayscale can be used as the second thickness data of the electrode. Please refer to Figure 3 As shown, after the X-ray irradiates the electrode, copper foil image A7 and copper foil image B8 with a large grayscale are generated on the flat panel detector 5, and the distance between copper foil image A7 and copper foil image B8 is the second thickness data. This measurement method can ensure the accuracy of the second thickness data, and it is also convenient for taking and reading values. In addition, the flat panel detector 5 can directly read the second thickness data and upload the second thickness data to the controller for recording and storage. This improves the intelligence level of the entire battery process and is conducive to improving the processing efficiency of the entire battery production process.

[0098] Finally, the controller processes the first thickness data and the second thickness data to obtain the third thickness data. The controller compares the third thickness data with the outgoing standard. If the third thickness data meets the outgoing standard, the pole piece 1 is transferred to the starting position 8 of the next process; if the third thickness data does not meet the outgoing standard, the pole piece is returned to the static warehouse and left to stand for a second predetermined time.

[0099] In the above process, the controller combines the first thickness data and the second thickness data to calculate the third thickness data of the electrode 1. The controller compares the third thickness data with the outbound standard, and transports the electrode 1 whose third thickness data reaches the outbound standard to the starting position 8 of the next process through the conveyor belt 3 for subsequent processing. For the electrode 1 whose third thickness data does not reach the outbound standard, the controller transports the electrode 1 back to the static warehouse 2 through the conveyor belt 3 and allows it to rest for a second predetermined time until the third thickness data of these electrode 1 reaches the outbound standard, and then transports it to the starting position 8 of the next process. In this way, the thickness of the electrode is strictly controlled during the static outbound stage of the electrode, ensuring that the electrode 1 entering the next process is the electrode 1 whose thickness meets the processing standard, which is beneficial to ensure the efficiency of subsequent processing and the yield rate of the final product.

[0100] Among them, the second predetermined time is 6 hours to 48 hours. That is to say, for the pole piece 1 whose third thickness data does not meet the outbound standard after the second thickness detection, the controller will send the pole piece 1 back to the static warehouse 2 through the conveyor belt 3 for another 6 hours to 48 hours. The third thickness data is the ratio of the difference between the second thickness data and the first thickness data to the first thickness data. In other words, let the first thickness data be A, the second thickness data be B, and the third thickness data be C, that is, C = (BA) / A * 100%. The third thickness data intuitively reflects the growth of the second thickness data compared to the first thickness data, so it is more convenient for the controller to screen the pole piece 1 that meets the outbound standard. The lower limit value of the outbound standard is 2%-4%. That is, under normal circumstances, the third thickness data is greater than or equal to 2%, and the controller can determine that the thickness of the pole piece 1 after static meets the processing requirements of the next process. In a few cases, the lower limit value can be increased according to actual needs, such as 2.8%, 3.2%, etc. That is, if the third thickness data is greater than or equal to 2.8% or 3.2%, the controller can determine that the thickness of the electrode 1 after being left at rest meets the processing requirements of the next step.

[0101] In addition, the pole piece rebound thickness control method according to the embodiment of the present invention further includes:

[0102] The next process start position 8 identifies the film roll number of the electrode 1 and feeds back the identification result to the controller. The controller retrieves the static time of the electrode 1 in the static warehouse 2 according to the film roll number of the electrode 1. If the static time of the electrode 1 in the static warehouse 2 is less than the first predetermined time, the processing plan of the electrode 1 in the next process is immediately terminated.

[0103] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

[0104] It should be noted that for those of ordinary skill in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the scope of protection of the present invention. Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0105] The above is a detailed introduction to a pole piece rebound thickness control method and a pole piece rebound thickness control system provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the structure of the present invention and its core idea; at the same time, for general technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for controlling the rebound thickness of a pole piece, characterized in that: The method comprises: Performing a first thickness test on the rolled pole piece to obtain first thickness data; Transferring the electrode to a static storage and allowing it to stand for a first predetermined time; Transferring the pole piece from the static storage to a testing station for a second thickness test to obtain second thickness data; Processing the first thickness data and the second thickness data to obtain third thickness data; The third thickness data is compared with the outgoing standard. If the third thickness data meets the outgoing standard, the pole piece is transferred to the starting position of the next process; if the third thickness data does not meet the outgoing standard, the pole piece is returned to the static warehouse and placed for a second predetermined time.

2. The pole piece rebound thickness control method according to claim 1, characterized in that: The step of transferring the pole piece from the static storage to the detection station for a second thickness detection to obtain second thickness data includes: The second thickness detection is performed on the pole piece by an X-ray thickness detection device.

3. The pole piece rebound thickness control method according to claim 2, characterized in that: The second thickness detection of the pole piece by an X-ray thickness detection device includes: Using the X-ray tube of the X-ray thickness detection device to penetrate and irradiate the pole piece along the tangent direction of the pole piece; The flat panel detector of the X-ray thickness detection device receives the X-ray after penetrating the pole piece and generates a grayscale image having the second thickness data.

4. The pole piece rebound thickness control method according to any one of claims 1 to 3, characterized in that: The method further comprises: When the first thickness data of the pole piece is obtained, a film roll number corresponding to the pole piece is synchronously generated, and a production database associating the film roll number with the first thickness data is established.

5. The pole piece rebound thickness control method according to claim 4, characterized in that: The step of transferring the electrode piece to a static storage and allowing it to stand for a first predetermined time comprises: Recording the time when the electrode enters the static storage and the film roll number; Record the static time of the corresponding electrode in the static storage according to the film roll number; According to the film roll number, the electrode pieces after being static for the first predetermined time are transferred out of the static storage in the order of the entry time.

6. The pole piece rebound thickness control method according to claim 5, characterized in that: The method further comprises: The next process starting position identifies the film roll number of the electrode; The resting time of the electrode in the static warehouse is retrieved according to the film roll number of the electrode. If the resting time of the electrode in the static warehouse is less than the first predetermined time, the processing plan of the electrode in the next process is immediately terminated.

7. The pole piece rebound thickness control method according to any one of claims 1 to 3, characterized in that: The first predetermined time is 24 hours to 168 hours.

8. The pole piece rebound thickness control method according to any one of claims 1 to 3, characterized in that: The second predetermined time is 6 hours to 48 hours.

9. The pole piece rebound thickness control method according to any one of claims 1 to 3, characterized in that: The third thickness data is a ratio of a difference between the second thickness data and the first thickness data to the first thickness data.

10. The pole piece rebound thickness control method according to claim 9, characterized in that: The lower limit value of the release standard is 2%-4%.

11. A pole piece rebound thickness control system, characterized in that: It comprises a controller, a first thickness detection mechanism, a static storage (2), a second thickness detection mechanism and a conveying mechanism; The first thickness detection mechanism is used to detect first thickness data of the electrode piece (1) after rolling; the static storage (2) is used to allow the electrode piece (1) after rolling to stand for a first predetermined time; the second thickness detection mechanism is used to detect second thickness data of the electrode piece (1) transferred from the static storage (2) after standing; the conveying mechanism is used to transport the electrode piece (1); The controller is used to process the first thickness data and the second thickness data to obtain third thickness data, and compare the third thickness data with the outgoing standard; if the third thickness data meets the outgoing standard, the pole piece (1) is transferred to the starting position (8) of the next process; if the third thickness data does not meet the outgoing standard, the pole piece (1) is returned to the static storage (2) and is statically placed for a second predetermined time.

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