Cylinder surface washing device and magnetic foreign object detection method

Abstract

This invention relates to the field of battery technology, and in particular to a washing device for the surface of a cylinder and a method for detecting magnetic materials. The washing device includes: 1) a mechanical rotation system; 2) a fluid supply system; 3) a water collection and recovery system; and 4) a central control system. The washing device for the cylindrical surface of this invention achieves complete control of washing elements, including washing angle, washing speed, washing flow rate, and washing time, through electromechanical and fluid control. This fundamentally eliminates the uncertainty of manual operation and ensures high consistency and repeatability of batch cleaning results.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to a washing device for the surface of a cylinder and a method for detecting magnetic materials. Background Technology

[0002] In the battery material production process, the incorporation of magnetic foreign matter (such as metal particles like iron, nickel, and cobalt) can lead to risks such as micro-short circuits and electrolyte contamination, severely impacting battery safety, cycle life, and energy density. Therefore, accurate detection of magnetic foreign matter in battery materials is a core aspect of quality control. Battery material development and updates are entering a phase of rapid growth. In the process of testing large quantities of various materials, mainstream and universally applicable methods for testing magnetic foreign matter content all require high levels of manual operation. However, some key steps in the entire testing process have not yet formed standardized operating procedures, making it difficult to meet the consistency requirements of batch processing. Rinsing, as one of the key steps in the magnetic foreign matter detection process, aims to separate non-magnetic impurities and residual solution adhering to the surface of magnetic foreign matter through liquid washing, ensuring that the finally collected magnetic foreign matter meets the purity standards required for testing. Currently, the main methods are ultrasonic and repeated manual rinsing. This manual rinsing mode has significant technical bottlenecks and poor consistency. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings and defects of the prior art and to provide a washing device for the surface of a cylinder and a method for detecting magnetic foreign objects.

[0004] To achieve the above objectives, this application adopts the following solution: A washing device for the surface of a cylinder, comprising: 1) Mechanical rotation system: used to clamp and drive a cylinder to rotate at a constant speed around its central axis; 2) Fluid supply system: used to provide a stable, controllable and uniformly distributed flushing fluid to the surface of the cylinder; 3) Water collection and recycling system: Located below the cylinder, it is used to collect and divert used flushing fluid to maintain a clean working environment; 4) Central control system: electrically connected to the mechanical rotation system and fluid supply system, used to control the entire rinsing process.

[0005] The mechanical rotation system includes a rigid frame and clamping components disposed at both ends of the rigid frame for clamping cylinders; one end of the clamping component is connected to the output end of a motor, and the other end of the clamping component is rotatably connected to the rigid frame.

[0006] The clamping component is a magnetic clamp; preferably, the magnetic clamp is a three-jaw chuck structure.

[0007] The fluid supply system includes a liquid storage tank and a water distributor connected to the liquid storage tank via a pipeline; the water distributor is located above the cylinder; preferably, a pump body is provided on the pipeline; preferably, the water distributor is a multi-hole spray pipe or a slit nozzle.

[0008] The present invention also includes a method for detecting magnetic foreign objects, using the aforementioned rinsing device for the surface of the cylinder.

[0009] Specifically, the steps include: 1) Adding the purified magnetic rod to a container holding the test material to fully adsorb the magnetic substances in the test material; 2) Placing the magnetic rod adsorbed with the magnetic substances in the test material on the surface of the cylinder by the two clamping parts of the mechanical rotation system of the rinsing device; starting the mechanical rotation system and the fluid supply system through the central control system, while the mechanical rotation system drives the magnetic rod to rotate, the fluid supply system rinses it; 3) Adding the cleaned magnetic rod to a container and using a digestion solution to digest the substances on the magnetic rod; 4) Detecting the magnetic substances in the obtained digestion solution.

[0010] The impurity removal of the magnetic rod in step 1) and the digestion process in step 3) are independently as follows: the magnetic rod is added to the digestion solution and heated; preferably, the heating temperature is 180-250℃ and the heating time is 10-60 min; more preferably, it is 200℃ and the heating time is 30 min; the digestion solution is a mixed acid solution, and the mixed acid is a mixture of hydrochloric acid and nitric acid; preferably, the volume ratio of hydrochloric acid to nitric acid is 1:3; the volume concentration of the mixed acid solution is 30-60%; more preferably, it is 50%.

[0011] Step 1) is as follows: Weigh the material to be tested into a clean sample container and add a solvent; preferably, the solvent is ultrapure water, NMP or anhydrous ethanol; add a clean magnetic rod, stretch the inner lid to seal it, tighten the inner lid, then cover it with the stretch film, then tighten the outer lid, and then seal the sealing film; after shaking it thoroughly, place the sample container on a grinding mill and grind it for 30-80 minutes; preferably 60 minutes, with the rotation speed set to 50-200 r / min, preferably 100 r / min, so that the magnetic rod can fully adsorb the magnetic substances in the material.

[0012] The rinsing solution includes ultrapure water, NMP, or anhydrous ethanol; the rinsing speed is 0.1~1 (r / s), and 0.5 r / s during rinsing; the rinsing flow rate is 50~1000 ml, preferably 500 ml; the rinsing angle is 45° to the surface of the magnetic rod; the rinsing time is 3~10 minutes, preferably 5 minutes.

[0013] Step 4) The detection method for magnetic materials is ICP-OES detection; the magnetic foreign material is one or a mixture of iron, cobalt, chromium, nickel, and zinc; Preferably, when the substance to be tested contains lithium iron phosphate and / or iron phosphide, and the magnetic foreign object is iron, the interference of iron in lithium iron phosphate and / or iron phosphide needs to be subtracted; preferably, the content of iron to be subtracted is obtained by the lithium element concentration and / or phosphorus element concentration.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The cylindrical surface rinsing device of this invention achieves complete control over rinsing elements, including rinsing angle, rinsing speed, rinsing flow rate, and rinsing time, through electromechanical and fluid control. This fundamentally eliminates the uncertainty of manual operation and ensures high consistency and repeatability of batch cleaning results. The device is highly automated; the entire rinsing process requires no manual intervention and is completed automatically after a single button start, greatly improving cleaning efficiency and reducing labor intensity. All key process parameters (speed, flow rate, and time) are settable, monitorable, and recordable digital values, providing a solid data foundation for product quality traceability and process optimization. Simultaneously, the device is used to detect magnetic foreign objects, ultimately improving the consistency of detection results. Attached Figure Description

[0015] Figure 1 This is an overall schematic diagram of the rinsing device for the cylindrical surface of the present invention. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0017] See appendix Figure 1 A washing device for the surface of a cylinder is shown, comprising: 1) Mechanical Rotation System 3: Used to clamp and drive a cylinder to rotate uniformly around its central axis; the mechanical rotation system includes a rigid frame and clamping components disposed at both ends of the rigid frame for clamping the cylinder; one end of the clamping component is connected to the output end of a motor, and the other end of the clamping component is rotatably connected to the rigid frame. The clamping component is a magnetic clamp; the magnetic clamp is a three-jaw chuck structure.

[0018] 2) Fluid supply system 4: used to provide a stable, controllable and uniformly distributed flushing fluid to the surface of the cylinder; the fluid supply system includes a liquid storage tank and a water distributor connected to the liquid storage tank through a pipeline; the water distributor is located above the cylinder; a pump body is installed on the pipeline; the water distributor has a multi-hole spray pipe or a slit nozzle.

[0019] 3) Water collection and recycling system 2: Located below the cylinder, it is used to collect and divert used flushing liquid to keep the working environment clean; 4) Central control system 1: Electrically connected to the mechanical rotation system and fluid supply system, used to control the entire flushing process.

[0020] This invention also includes a method for detecting magnetic foreign objects, using the aforementioned rinsing device for the surface of the cylinder. Specifically, it includes the following steps: 1) After impurity removal, add the magnetic rod to the container holding the test material to fully adsorb the magnetic substances in the test material. The impurity removal process of the magnetic rod is as follows: Place the magnetic rod in a clean test tube, add 8 mL of ultrapure water, then add 6 mL of concentrated hydrochloric acid and 2 mL of concentrated nitric acid to submerge the magnetic rod. Pour 100 mL of ultrapure water into a 250 mL Erlenmeyer flask, heat the test tube through the Erlenmeyer flask in a water bath, and place the Erlenmeyer flask on a constant temperature electric heating plate at 200 ℃ for 30 min. After heating, remove the Erlenmeyer flask and allow it to cool naturally to room temperature. Then wash the magnetic rod three times with ultrapure water and set aside. Accurately weigh 200g of the test material into a clean sample container, add 300mL of ultrapure water, add the cleaned magnetic rod from the previous step, seal the inner lid with stretch film, tighten the inner lid, then cover with stretch film, tighten the outer lid, and seal with sealing film; shake thoroughly, then place the sample container on a grinding mill for 60 min at a speed of 100 r / min to allow the magnetic rod to fully adsorb the magnetic substances in the material; 2) The magnetic rod, which adsorbs the magnetic material from the test material, is placed on the surface of the cylinder by the two clamping components of the mechanical rotation system of the rinsing device; the parameters are set through the central control system: target rotation speed 'N' = 0.5 r / s, target rinsing flow rate 'Q' = 500 ml, and total rinsing time 'T' = 5 min; the mechanical rotation system and the fluid supply system are started. While the mechanical rotation system drives the magnetic rod to rotate at the set speed 'N', the fluid supply system provides rinsing liquid at the set flow rate 'Q'. The rinsing liquid is evenly sprayed from the water distributor at a vertical rinsing angle of 45°, covering the entire surface of the rotating magnetic rod; the rinsing process continues until the preset time 'T' is reached, at which point the system automatically stops; a clean beaker is placed under the magnetic rod, the operator presses the "power off" (OFF) button, and rotates the wrench counterclockwise to release the clamps, and the magnetic rod is transferred into the beaker.

[0021] 3) Add the cleaned magnetic rod to the container and digest the residue on the magnetic rod using the digestion solution. Slowly place the cleaned magnetic rod into a clean test tube, add 8 mL of ultrapure water, then add 6 mL of concentrated hydrochloric acid and 2 mL of concentrated nitric acid to submerge the magnetic rod. Pour 100 mL of ultrapure water into a 250 mL Erlenmeyer flask. Heat the test tube through the Erlenmeyer flask in a water bath, and place the Erlenmeyer flask on a constant temperature heating plate at 200 °C for 30 min. After heating, allow it to cool naturally to room temperature. Use another magnetic rod to absorb the residue from the test tube, pour the solution into a volumetric flask, dilute to the mark with ultrapure water, and shake well. Simultaneously, prepare a blank sample.

[0022] 4) Detect magnetic substances in the obtained digest. The detection method for magnetic substances is ICP-OES detection; the magnetic foreign matter is one or a mixture of iron, cobalt, chromium, nickel, and zinc; when the analyte contains lithium iron phosphate and / or iron phosphide, and the magnetic foreign matter is determined to be iron, the interference of iron in lithium iron phosphate and / or iron phosphide needs to be subtracted; preferably, the content of iron to be subtracted is obtained by the lithium element concentration and / or phosphorus element concentration.

[0023] To reduce interference from the small amount of adsorbed lithium iron phosphate, Method 1 is used for calculation. Based on the chemical formula of lithium iron phosphate (LiFePO4), the P:Fe ratio is determined to be 1:1. The iron concentration in lithium iron phosphate is calculated from the phosphorus concentration, the molar mass of phosphorus and iron, and the phosphorus-iron ratio. The iron content in the magnetic material of the sample is then calculated by subtracting the iron concentration in lithium iron phosphate from the total iron concentration detected. Alternatively, Method 2 is used. First, the Li:Fe ratio is determined to be 1:1 based on the chemical formula of lithium iron phosphate (LiFePO4). The iron concentration in lithium iron phosphate is calculated from the lithium concentration, the molar mass of lithium and iron, and the lithium-iron ratio. The iron content in the magnetic material of the sample is then calculated by subtracting the iron concentration in lithium iron phosphate from the total iron concentration detected.

[0024] However, with the continuous updates and iterations of high-performance materials, the iron phosphide content in lithium iron phosphate materials is constantly increasing. To reduce the interference from adsorbed lithium iron phosphate and iron phosphide, an upgraded detection method is adopted. First, based on the chemical formula of lithium iron phosphate (LiFePO4), the Li:Fe ratio is determined to be 1:1 and the Li:P ratio is determined to be 1:1. The iron and phosphorus concentrations in lithium iron phosphate are calculated from the lithium element concentration, the molar mass of lithium, iron, and phosphorus, the lithium-iron ratio, and the lithium-phosphorus ratio. Second, based on the chemical formula of iron phosphide (Fe2P), the P:Fe ratio is determined to be 1:2. The phosphorus concentration in iron phosphide is obtained by subtracting the phosphorus concentration in lithium iron phosphate from the total phosphorus element concentration. The iron concentration in iron phosphide is then calculated from the phosphorus concentration in iron phosphide, the molar mass of iron and phosphorus, and the phosphorus-iron ratio. Finally, the elemental iron content in the magnetic material of the sample is calculated by subtracting the iron concentrations in lithium iron phosphate and iron phosphide from the total iron concentration.

[0025] The proposed method was used to test different lithium iron phosphate slurries, and the results are shown in Table 1.

[0026] Table 1

[0027] Results Comparison: The following provides comparative data on the test and detection results of positive electrode powder and slurry. The comparative experiment shows that the magnetic rod rinsing effect is better and more consistent after the use of automated rinsing.

[0028] Table 2-3 shows the data for manual rinsing and automatic rinsing, indicating that the test data are more consistent after automatic rinsing.

[0029] Table 2

[0030] Table 3

[0031]

[0032] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of the equivalents of the claims be included within the invention.

[0033] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A rinsing device for the surface of a cylinder, characterized in that, include: 1) Mechanical rotation system: used to clamp and drive a cylinder to rotate at a constant speed around its central axis; 2) Fluid supply system: used to provide a stable, controllable and uniformly distributed flushing fluid to the surface of the cylinder; 3) Water collection and recycling system: Located below the cylinder, it is used to collect and divert used flushing fluid to maintain a clean working environment; 4) Central control system: electrically connected to the mechanical rotation system and fluid supply system, used to control the entire rinsing process.

2. The washing device for the surface of a cylinder according to claim 1, characterized in that, The mechanical rotation system includes a rigid frame and clamping components disposed at both ends of the rigid frame for clamping cylinders; one end of the clamping component is connected to the output end of a motor, and the other end of the clamping component is rotatably connected to the rigid frame.

3. The washing device for the cylindrical surface according to claim 1, characterized in that, The clamping component is a magnetic clamp; preferably, the magnetic clamp is a three-jaw chuck structure.

4. The washing device for the cylindrical surface according to claim 1, characterized in that, The fluid supply system includes a liquid storage tank and a water distributor connected to the liquid storage tank via a pipeline; the water distributor is located above the cylinder; preferably, a pump body is provided on the pipeline; preferably, the water distributor is a multi-hole spray pipe or a slit nozzle.

5. A method for detecting magnetic foreign objects, characterized in that, Use the rinsing device for the cylindrical surface as described in any one of claims 1-3.

6. The method for detecting magnetic foreign objects according to claim 4, characterized in that, Specifically, the steps include: 1) adding the purified magnetic rod to a container holding the test material to fully adsorb the magnetic substances in the test material; 2) placing the magnetic rod adsorbed with the magnetic substances in the test material on the two clamping components of the mechanical rotation system of the rinsing device for the cylindrical surface as described in any one of claims 1-4; starting the mechanical rotation system and the fluid supply system through the central control system, and rinsing the magnetic rod during the process of the mechanical rotation system driving the magnetic rod to rotate; 3) adding the cleaned magnetic rod to a container and using a digestion solution to digest the substances on the magnetic rod; 4) detecting the magnetic substances in the obtained digestion solution.

7. The method for detecting magnetic foreign objects according to claim 5, characterized in that, The impurity removal of the magnetic rod in step 1) and the digestion process in step 3) are independently as follows: the magnetic rod is added to the digestion solution and heated; preferably, the heating temperature is 180-250℃ and the heating time is 10-60 min; more preferably, it is 200℃ and the heating time is 30 min; the digestion solution is a mixed acid solution, and the mixed acid is a mixture of hydrochloric acid and nitric acid; preferably, the volume ratio of hydrochloric acid to nitric acid is 1:3; the volume concentration of the mixed acid solution is 30-60%; more preferably, it is 50%.

8. The method for detecting magnetic foreign objects according to claim 5, characterized in that, Step 1) is as follows: Weigh the material to be tested into a clean sample container and add a solvent; preferably, the solvent is ultrapure water, NMP or anhydrous ethanol; add a clean magnetic rod, stretch the inner lid to seal it, tighten the inner lid, then cover it with the stretch film, then tighten the outer lid, and then seal the sealing film; after shaking it thoroughly, place the sample container on a grinding mill and grind it for 30-80 minutes; preferably 60 minutes, with the rotation speed set to 50-200 r / min, preferably 100 r / min, so that the magnetic rod can fully adsorb the magnetic substances in the material.

9. The method for detecting magnetic foreign objects according to claim 5, characterized in that, The rinsing solution includes ultrapure water, NMP, or anhydrous ethanol; the rinsing speed is 0.1~1 (r / s), and 0.5 r / s during rinsing; the rinsing flow rate is 50~1000 ml, preferably 500 ml; the rinsing angle is 45° to the surface of the magnetic rod; the rinsing time is 3~10 minutes, preferably 5 minutes.

10. The method for detecting magnetic foreign objects according to claim 5, characterized in that, Step 4) The detection method for magnetic materials is ICP-OES detection; the magnetic foreign material is one or a mixture of iron, cobalt, chromium, nickel, and zinc; Preferably, when the substance to be tested contains lithium iron phosphate and / or iron phosphide, and the magnetic foreign object is iron, the interference of iron in lithium iron phosphate and / or iron phosphide needs to be subtracted; preferably, the content of iron to be subtracted is obtained by the lithium element concentration and / or phosphorus element concentration.

Images