A device for separating and enriching metal impurities in a battery positive electrode

Abstract

The embodiment of the application provides a battery positive electrode metal impurity separation and enrichment device, which comprises a shell, the shell comprises a containing groove, the containing groove is used for filling an electrolyte; a positive electrode back plate, the positive electrode back plate is at least partially arranged in the containing groove, and one side surface of the positive electrode back plate is provided with a positive electrode material layer; a negative electrode back plate, the negative electrode back plate is at least partially arranged in the containing groove, and one side surface of the negative electrode back plate is provided with a negative electrode material layer, wherein the negative electrode material layer is opposite to the positive electrode material layer and has a gap; a positive electrode connecting shaft for connecting a positive electrode of an external power supply, the positive electrode connecting shaft is connected with the positive electrode back plate; a negative electrode connecting shaft for connecting a negative electrode of the external power supply, the negative electrode connecting shaft is connected with the negative electrode back plate. The application separates and enriches non-magnetic metal impurities in the positive electrode material by using an electrochemical method, and improves the safety and reliability of the battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a device for separating and enriching metallic impurities in the positive electrode of a battery. Background Technology

[0002] Currently, during the production of lithium battery cathode materials, metal impurities are inevitably introduced due to the influence of processes and equipment. These metal impurities enter the lithium battery through the battery production process, dissolve at the high-potential cathode, and then precipitate along the pores of the separator, connecting the positive and negative electrodes, thus causing internal short circuits. This is one of the causes of internal short circuits in batteries, seriously threatening the safety and durability of lithium batteries. Therefore, it is necessary to strictly control the content of metal impurities in raw materials. Utility Model Content

[0003] The purpose of this application is to provide a battery cathode metal impurity separation and enrichment device to solve the technical problem in the related art that excessive impurities in lithium battery cathode materials lead to poor battery safety and durability.

[0004] This application provides a battery positive electrode metal impurity separation and enrichment device, comprising: a housing, the housing including a receiving groove for filling electrolyte; a positive electrode backplate, at least partially disposed within the receiving groove, with a positive electrode material layer disposed on one side surface of the positive electrode backplate; a negative electrode backplate, at least partially disposed within the receiving groove, with a negative electrode material layer disposed on one side surface of the negative electrode backplate, wherein the negative electrode material layer is opposite to the positive electrode material layer and has a gap; a positive electrode connecting shaft for connecting to the positive electrode of an external power source, the positive electrode connecting shaft being connected to the positive electrode backplate; and a negative electrode connecting shaft for connecting to the negative electrode of an external power source, the negative electrode connecting shaft being connected to the negative electrode backplate.

[0005] This application connects the positive electrode to the positive electrode of the power supply via a positive electrode connecting shaft and the negative electrode connecting shaft to the negative electrode of the power supply. The positive electrode backplate and the negative electrode backplate are energized. An electrochemical method is used to raise the potential of the positive electrode powder containing non-magnetic metal impurities to above the metal dissolution potential. Based on the principle that metals dissolve at high potentials and precipitate at low potentials, the metal impurities are separated onto the negative electrode backplate, thereby improving battery safety and durability.

[0006] In some embodiments, an annular spacer is provided between the positive electrode material layer and the negative electrode material layer, wherein the annular spacer is configured to sandwich the positive electrode material layer and the negative electrode material layer between them. The annular spacer exerts a certain counter-pressure on the positive electrode material layer on the positive electrode backplate and the negative electrode material layer on the negative electrode backplate, preventing the positive electrode material layer and the negative electrode material layer from falling off.

[0007] In some embodiments, the annular insulating pad contacts the edges of both the positive electrode material layer and the negative electrode material layer, effectively preventing the material layers from detaching from the edges.

[0008] In some embodiments, the housing includes a first through hole and a second through hole located on both sides of the receiving groove and communicating with the receiving groove; the positive electrode connecting shaft is slidably inserted through the first through hole, with one end of the positive electrode connecting shaft abutting against the positive electrode back plate and the other end extending out of the housing; the negative electrode connecting shaft is slidably inserted through the second through hole, with one end of the negative electrode connecting shaft abutting against the negative electrode back plate and the other end extending out of the housing.

[0009] In some embodiments, the device further includes: a first knob and a second knob; the first knob is threadedly connected to the first through hole, the positive electrode connecting shaft passes through the first knob, and a first spring is connected between the head of the first knob and the positive electrode connecting shaft; the second knob is threadedly connected to the second through hole, the negative electrode connecting shaft passes through the second knob, and a second spring is connected between the head of the second knob and the negative electrode connecting shaft. The spring force ensures that the force on the positive and negative electrode backplates is within the required range, preventing the edges of the positive electrode material layer on the positive electrode backplate and the edges of the negative electrode material layer on the negative electrode backplate from being pressed together by the annular insulating pad while remaining undamaged.

[0010] In some embodiments, the positive electrode connecting shaft is stepped, the first spring is sleeved on the positive electrode connecting shaft, with one end abutting against the stepped surface of the positive electrode connecting shaft and the other end abutting against the head of the first knob; the negative electrode connecting shaft is stepped, the second spring is sleeved on the negative electrode connecting shaft, with one end abutting against the stepped surface of the negative electrode connecting shaft and the other end abutting against the head of the second knob.

[0011] In some embodiments, a first sealing ring is provided between the positive electrode connecting shaft and the inner wall of the first through hole; a second sealing ring is provided between the negative electrode connecting shaft and the inner wall of the second through hole.

[0012] In some embodiments, one or more flow channels for electrolyte flow are provided on the sides of the positive electrode backplate and the negative electrode backplate. The flow channels may be semi-circular to facilitate electrolyte flow in the housing receiving tank, thereby immersing the positive electrode material layer on the positive electrode backplate and the negative electrode material layer on the negative electrode backplate.

[0013] In some embodiments, a limiting protrusion is formed in the receiving groove, the limiting protrusion dividing the receiving groove into a first receiving groove and a second receiving groove, wherein the positive electrode backplate is disposed in the first receiving groove and the negative electrode backplate is disposed in the second receiving groove; a stepped structure is formed on the top of the positive electrode backplate and the top of the negative electrode backplate respectively.

[0014] In some embodiments, it further includes: a top cover disposed on the housing and covering the receiving groove. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A perspective view of a battery cathode metal impurity separation and enrichment device provided in this application embodiment; Figure 2 A top view of a battery cathode metal impurity separation and enrichment device provided in this application embodiment; Figure 3 Provided for the embodiments of this application Figure 2 Cross-sectional view of the device for separating and enriching metallic impurities at the positive electrode of a mid-cell battery; Figure 4 This is a schematic diagram of the internal structure of a battery cathode metal impurity separation and enrichment device after removing the top cover, as provided in an embodiment of this application. Figure 5 This is a schematic diagram of the positive electrode backplate structure provided in an embodiment of this application. Detailed Implementation

[0017] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0018] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0019] During the production of lithium-ion battery cathode materials, metallic impurities are inevitably introduced due to factors such as process and equipment conditions. These impurities, once inside the lithium-ion battery through the production process, dissolve at the high-potential cathode and then precipitate along the separator pores, connecting the positive and negative electrodes, thus causing internal short circuits. This seriously threatens the safety and durability of the lithium-ion battery, necessitating strict control of the metallic impurity content in the raw materials. However, currently, there are no standardized and efficient methods for detecting metallic impurities in cathode materials.

[0020] Metallic impurities mixed in battery cathode materials, such as iron, cobalt, and nickel, are ferromagnetic and can therefore be adsorbed and separated from the material by applying a strong magnetic field. However, for other non-magnetic substances, there is currently no effective method for separation and enrichment. Meanwhile, among the many non-magnetic metallic impurities, copper and zinc pose the greatest risk of causing internal short circuits. Without effective separation methods, this will pose a significant hidden danger to lithium batteries and severely restrict their development.

[0021] In view of the above problems, this application provides a device for separating and enriching metal impurities in battery cathode materials, which uses electrochemical methods to separate and enrich non-magnetic metal impurities in cathode materials.

[0022] Figure 1 A perspective view of a battery cathode metal impurity separation and enrichment device provided in this application embodiment; Figure 2 A top view of a battery cathode metal impurity separation and enrichment device provided in this application embodiment; Figure 3 Provided for the embodiments of this application Figure 2 Cross-sectional view of the device for separating and enriching metal impurities at the positive electrode of a battery.

[0023] Please refer to Figures 1-3 This application provides a battery positive electrode metal impurity separation and enrichment device, including: a housing 10, a positive electrode back plate 21, a negative electrode back plate 22, a positive electrode connecting shaft 31, and a negative electrode connecting shaft 32.

[0024] The housing 10 includes a receiving tank 11 for filling with electrolyte. Furthermore, the receiving tank 11 is also used to place the positive electrode backplate 21 and the negative electrode backplate 22, thereby immersing them in the electrolyte. A top cover 14 can be attached to the housing 10 to seal the opening of the receiving tank 11, thus forming a sealed space within the receiving tank 11.

[0025] Specifically, at least a portion of the positive electrode backplate 21 is disposed within the receiving tank 11, and a positive electrode material layer 23 is disposed on one side surface of the positive electrode backplate 21. At least a portion of the negative electrode backplate 22 is disposed within the receiving tank 11, and a negative electrode material layer 24 is disposed on one side surface of the negative electrode backplate 22. The negative electrode material layer 24 is opposite to the positive electrode material layer 23 and there is a certain gap between them, so that electrons can move when the positive electrode backplate 21 and the negative electrode backplate 22 are energized, and positive electrode metal impurities are separated and enriched towards the negative electrode backplate. When the positive electrode backplate 21 is placed in the receiving tank 11, the positive electrode material layer on it is immersed in the electrolyte. The top of the positive electrode backplate 21 can protrude from the receiving tank 11, and the part protruding from the receiving tank 11 can be uncoated with a positive electrode material layer for easy removal and placement. Similarly, when the negative electrode backplate 22 is placed in the receiving tank 11, the positive electrode material layer on it is immersed in the electrolyte. The top of the negative electrode backplate 22 can protrude from the receiving tank 11, and the part protruding from the receiving tank 11 can be uncoated with the negative electrode material layer to facilitate removal and placement.

[0026] The positive terminal connecting shaft 31 is connected to the positive terminal back plate 21 and is used to connect to the positive terminal of an external power supply. The negative terminal connecting shaft 32 is connected to the negative terminal back plate 22 and is used to connect to the negative terminal of an external power supply. One end of the positive terminal connecting shaft 31 can be connected to or in contact with the positive terminal back plate 21, while the other end can extend outside the housing 10 to connect to the positive terminal of the power supply and energize the positive terminal back plate 21. Similarly, one end of the negative terminal connecting shaft 32 can be connected to or in contact with the negative terminal back plate 22, while the other end can extend outside the housing 10 to connect to the negative terminal of the power supply and energize the negative terminal back plate 22.

[0027] To address the critical issue of the difficulty in effectively separating and enriching non-magnetic metallic impurities in the positive electrode material on the positive electrode backplate 21, this application connects the positive electrode to the positive electrode of the power supply via a positive electrode connecting shaft 31 and a negative electrode connecting shaft 32. When the positive electrode backplate 21 and the negative electrode backplate 22 are energized, the potential of the positive electrode powder containing non-magnetic metallic impurities is raised above the metal dissolution potential using an electrochemical method. Utilizing the principle that metals dissolve at high potentials and precipitate at low potentials, the metallic impurities are separated onto the negative electrode backplate 22, thereby improving battery safety and durability.

[0028] In some embodiments, an annular insulating pad 50 is provided between the positive electrode material layer 23 and the negative electrode material layer 24, wherein the annular insulating pad 50 is configured to clamp between the positive electrode material layer 23 and the negative electrode material layer 24. A certain opposing force (axial force) can be applied to the positive electrode backplate 21 and the negative electrode backplate 22 respectively by the positive electrode connecting shaft 31 and the negative electrode connecting shaft 32, causing the positive electrode backplate 21 and the negative electrode backplate 22 to clamp the annular insulating pad 50. In this way, the annular insulating pad 50 forms a certain counter-pressure on the positive electrode material layer 23 on the positive electrode backplate 21 and the negative electrode material layer 24 on the negative electrode backplate 22, preventing the positive electrode material layer 23 and the negative electrode layer 24 from detaching.

[0029] Among them, the positive electrode material layer 23 on the positive electrode backplate 21 and the negative electrode material layer 24 on the negative electrode backplate 22 are more prone to detachment closer to the edge. In this application, the annular insulating pad 50 contacts the edges of the positive electrode material layer 23 and the negative electrode material layer 24 respectively, effectively preventing the material layer at the edge from detaching.

[0030] The aforementioned annular isolation pad 50 can be a circular isolation pad, a square isolation pad, or a square-shaped isolation pad.

[0031] In some embodiments, the housing 10 includes a first through hole 12 and a second through hole 13 located on both sides of the receiving groove 11 and communicating with the receiving groove 11. A positive electrode connecting shaft 31 is slidably inserted into the first through hole 12, with one end abutting against the back side (the side not coated with positive electrode material) of the positive electrode back plate 21, and the other end extending out of the housing 10. A negative electrode connecting shaft 32 is slidably inserted into the second through hole 13, with one end abutting against the back side (the side not coated with negative electrode material) of the negative electrode back plate 22, and the other end extending out of the housing 10. A first sealing ring 61 is provided between the positive electrode connecting shaft 31 and the inner wall of the first through hole 12; a second sealing ring 62 is provided between the negative electrode connecting shaft 32 and the inner wall of the second through hole 13, thereby preventing electrolyte leakage from the receiving groove 11.

[0032] The positive electrode connecting shaft 31 and the negative electrode connecting shaft 32 can be pushed by external force to move towards each other against the positive electrode back plate 21 and the negative electrode back plate 22 respectively, thereby clamping the annular isolation pad 50.

[0033] Furthermore, the first through hole 12 and the second through hole 13 can be threaded through holes, with the first knob 41 and the second knob 42 threadedly connected to the first through hole 12 and the second through hole 13, respectively. The positive electrode connecting shaft 31 passes through the first knob 41, and a first spring 43 is connected between the head of the first knob 41 and the positive electrode connecting shaft 31. The negative electrode connecting shaft 32 passes through the second knob 42, and a second spring 44 is connected between the head of the second knob and the negative electrode connecting shaft 32. The two ends of the first spring 43 can be fixedly connected to the head of the first knob 41 and the positive electrode connecting shaft 31, respectively, or they can abut against the head of the first knob 41 and the positive electrode connecting shaft 31, respectively. Similarly, the two ends of the second spring 44 can be fixedly connected to the head of the second knob 42 and the negative electrode connecting shaft 32, respectively, or they can abut against the head of the second knob 42 and the negative electrode connecting shaft 32, respectively.

[0034] In use, screw in the first knob 41 and the second knob 42. The first knob 41 and the second knob 42 respectively compress the springs. The springs push the positive electrode connecting shaft 31 and the negative electrode connecting shaft 32 toward the positive electrode back plate 21 and the negative electrode back plate 22 respectively, pushing the positive electrode back plate 21 and the negative electrode back plate 22 to press against the annular insulating pad 50. The elastic force of the springs ensures that the force on the positive and negative electrode back plates is within the required range, preventing the edges of the positive electrode material layer on the positive electrode back plate 21 and the edges of the negative electrode material layer on the negative electrode back plate 22 from being pressed by the annular insulating pad 50 without being damaged.

[0035] Furthermore, the positive electrode connecting shaft 31 can be stepped, with the first spring 43 sleeved on the positive electrode connecting shaft 31, one end abutting against the stepped surface of the positive electrode connecting shaft 31 and the other end abutting against the head end face of the first knob; the negative electrode connecting shaft 32 can also be stepped, with the second spring 44 sleeved on the negative electrode connecting shaft 32, one end abutting against the stepped surface of the negative electrode connecting shaft 32 and the other end abutting against the head end face of the second knob 42.

[0036] In some embodiments, refer to Figure 5 One or more flow channels 211 for electrolyte flow are provided on the side of the positive electrode backplate 21 and the side of the negative electrode backplate 22. The flow channels 211 may be semi-circular to facilitate electrolyte flow in the housing receiving tank 11.

[0037] In one example, the top of the positive electrode backplate 21 and the top of the negative electrode backplate 22 are respectively formed with stepped structures. A limiting protrusion is formed in the housing receiving groove 11, which divides the receiving groove 11 into a first receiving groove and a second receiving groove. The positive electrode backplate 21 is disposed in the first receiving groove, and the negative electrode backplate 22 is disposed in the second receiving groove. The positive electrode backplate 21 can move toward the negative electrode backplate 22 in the first receiving groove, and the negative electrode backplate 22 can move toward the positive electrode backplate 21 in the second receiving groove, limited by the intermediate limiting protrusion.

[0038] In one example, the battery cathode metal impurity separation and enrichment device of this application is used as follows: First, place the positive electrode backplate 21 and the negative electrode backplate 22 into the housing receiving groove 11, so that the positive electrode material layer 23 on the positive electrode backplate 21 is opposite to the negative electrode material layer 24 on the negative electrode backplate 22, and place an annular isolation pad 50 between the positive electrode material layer 23 and the negative electrode material layer 24. Then, install sealing rings on the positive electrode connecting shaft 31 and the negative electrode connecting shaft 32 respectively, and then install them into the first through hole 12 and the second through hole 13 on the housing 10 respectively. One end of the positive electrode connecting shaft 31 and the negative electrode connecting shaft 32 extends into the receiving groove of the housing 10 and abuts against the positive electrode backplate 21 and the negative electrode backplate 22 respectively. Next, install the spring, screw in the hand-tightening bolt, and inject electrolyte into the housing groove, which is higher than the annular isolation pad 50. The water flow grooves 211 on both sides of the positive and negative electrode backplates help the electrolyte flow. Finally, install the top cover 14 to seal. Tighten the first knob 41 and the second knob 42. The knobs compress the springs, which in turn push the positive electrode connecting shaft 31 and the negative electrode connecting shaft 32 to move towards each other, ultimately pressing the positive and negative electrode back plates against the annular separator 50. Then, connect the positive and negative electrode power sources to the positive and negative electrode connecting shafts 31 and 32 extending from the housing 10 to energize the battery. When the positive electrode back plate 21 and the negative electrode back plate 22 are energized, an electrochemical method is used to raise the potential of the positive electrode powder containing non-magnetic metal impurities above the metal dissolution potential. Utilizing the principle that metals dissolve at high potentials and precipitate at low potentials, the metal impurities are separated onto the negative electrode back plate 22, thereby improving battery safety and durability.

[0039] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0040] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the aforementioned scope of rights.

[0041] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A device for separating and enriching metallic impurities in the positive electrode of a battery, characterized in that, include: A housing, the housing including a receiving tank for filling an electrolyte; A positive electrode backplate, wherein at least part of the positive electrode backplate is disposed within the receiving groove, and a positive electrode material layer is disposed on one side surface of the positive electrode backplate; A negative electrode backplate, wherein the negative electrode backplate is at least partially disposed within the receiving groove, and a negative electrode material layer is disposed on one side surface of the negative electrode backplate, wherein the negative electrode material layer is opposite to the positive electrode material layer and has a gap; A positive terminal connecting shaft for connecting to the positive terminal of an external power source, the positive terminal connecting shaft being connected to the positive terminal backplate; A negative terminal connecting shaft for connecting to the negative terminal of an external power supply, the negative terminal connecting shaft being connected to the negative terminal backplate.

2. The battery cathode metal impurity separation and enrichment device according to claim 1, characterized in that, An annular insulating pad is disposed between the positive electrode material layer and the negative electrode material layer, wherein the annular insulating pad is configured to be sandwiched between the positive electrode material layer and the negative electrode material layer.

3. The battery cathode metal impurity separation and enrichment device according to claim 2, characterized in that, The annular insulating pad is in contact with the edges of the positive electrode material layer and the negative electrode material layer, respectively.

4. The battery cathode metal impurity separation and enrichment device according to claim 2, characterized in that, The housing includes a first through hole and a second through hole located on both sides of the receiving groove and communicating with the receiving groove; The positive electrode connecting shaft is slidably inserted into the first through hole, with one end of the positive electrode connecting shaft abutting against the positive electrode back plate and the other end extending out of the housing; The negative electrode connecting shaft is slidably inserted into the second through hole, with one end of the negative electrode connecting shaft abutting against the negative electrode back plate and the other end extending out of the housing.

5. The battery cathode metal impurity separation and enrichment device according to claim 4, characterized in that, Also includes: A first knob and a second knob, wherein the first knob is threadedly connected to the first through hole, the positive electrode connecting shaft passes through the first knob, and a first spring is connected between the head of the first knob and the positive electrode connecting shaft; the second knob is threadedly connected to the second through hole, the negative electrode connecting shaft passes through the second knob, and a second spring is connected between the head of the second knob and the negative electrode connecting shaft.

6. The battery cathode metal impurity separation and enrichment device according to claim 5, characterized in that, The positive electrode connecting shaft is stepped, and the first spring is sleeved on the positive electrode connecting shaft, with one end abutting against the stepped surface of the positive electrode connecting shaft and the other end abutting against the head of the first knob. The negative electrode connecting shaft is stepped, and the second spring is sleeved on the negative electrode connecting shaft, with one end abutting against the stepped surface of the negative electrode connecting shaft and the other end abutting against the head of the second knob.

7. The battery cathode metal impurity separation and enrichment device according to claim 4, characterized in that, A first sealing ring is provided between the positive electrode connecting shaft and the inner wall of the first through hole; A second sealing ring is provided between the negative electrode connecting shaft and the inner wall of the second through hole.

8. The battery cathode metal impurity separation and enrichment apparatus according to any one of claims 1-7, characterized in that, The top of the positive electrode backplate and the side of the negative electrode backplate are provided with one or more water channels for the flow of electrolyte.

9. The battery cathode metal impurity separation and enrichment device according to claim 8, characterized in that, A limiting protrusion is formed in the receiving groove, and the limiting protrusion divides the receiving groove into a first receiving groove and a second receiving groove, wherein the positive electrode back plate is disposed in the first receiving groove and the negative electrode back plate is disposed in the second receiving groove; The top of the positive electrode backplate and the top of the negative electrode backplate are respectively formed with stepped structures.

10. The battery cathode metal impurity separation and enrichment device according to claim 8, characterized in that, Also includes: The cover is disposed on the housing and seals the receiving groove.

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