Three-electrode electrochemical device, circuit system
By using triode ear electrochemical device in lithium-ion batteries, the current path is constructed using the third ear and the negative or positive electrode of the battery cell to achieve quantitative lithium supplementation in the chemical formation and circulation stages, the problems of complex lithium supplementation process and reduced energy density in the existing technology are solved, and the energy density and cycle stability of the battery cell are improved.
Patent Information
- Application Number
- CN202421061636.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-15
- Publication Date
- 2025-04-01
- Estimated Expiration
- 2034-05-15
AI Technical Summary
The existing lithium-ion battery lithium replenishment technology has the problem of complex process, inability to supplement lithium during circulation, and the use of positive electrode lithium replenishing agents to reduce the energy density of the battery cell.
The triode ear electrochemical device is adopted, including a laminated battery cell, a lithium-rich electrode sheet located on both sides of the battery cell, and a third electrode ear. The current path is constructed through the third electrode ear and the negative electrode or the positive electrode to achieve quantitative lithium supplementation in the chemical formation and circulation stages.
It realizes quantitative lithium supplementation during the cell formation and circulation process, reduces the loss of active lithium, improves the energy density and cycle stability of the cell, and is simple to operate and adapts to the existing lithium battery process.
Smart Images
Figure CN222705575U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of lithium replenishment of lithium ion batteries, in particular to a three-electrode electrochemical device and a circuit system. Background Art
[0002] The loss of active lithium is one of the important reasons for the reduction of energy density and capacity decay of lithium-ion batteries. The loss of active lithium accompanies the entire production and use cycle of lithium-ion batteries. In the formation stage, active lithium and electrolyte-related components will decompose on the surface of positive and negative active materials to form a solid electrolyte film; in the circulation stage, the formation of dead lithium and the repair of the interface solid electrolyte film will also consume a large amount of active lithium.
[0003] Therefore, in order to improve the energy density and cycle performance of lithium-ion batteries, active lithium needs to be supplemented (lithium replenishment) during the battery formation and cycle process. At present, common lithium replenishment methods are mainly divided into negative electrode electrochemical lithium replenishment and the use of positive electrode lithium replenishers. The traditional electrochemical lithium replenishment process is complicated and difficult to use on a large scale. The emerging negative electrode electrochemical lithium replenishment introduces the lithium replenishment process into the formation stage, but it is still impossible to replenish lithium during the cycle process. Although the method of using positive electrode lithium replenishers is simple to operate and can be adapted to the existing battery cell preparation process, the introduction of positive electrode lithium replenishers will reduce the content of positive electrode active substances, thereby affecting the energy density of the battery cell; in addition, the positive electrode lithium replenisher is prone to gasification during the lithium replenishment process, which may damage the positive electrode sheet and battery cell structure. Utility Model Content
[0004] The utility model aims to provide a three-electrode electrochemical device and a circuit system, which solve the technical problems in the prior art of complicated process and inability to replenish lithium during the cycle when replenishing lithium at the negative electrode, as well as the reduced energy density of the battery cell caused by the use of a positive electrode lithium replenisher, and achieves the technical effect of quantitatively replenishing lithium during the battery cell formation stage and the cycle process.
[0005] In a first aspect, the utility model provides a three-electrode electrochemical device, comprising a laminated battery core, lithium-rich electrodes located on both sides of the laminated battery core, and a third electrode;
[0006] Wherein, the lithium-rich pole pieces located on both sides of the laminated battery core are welded to each other and lead out the third pole lug.
[0007] Furthermore, the structure of the laminated battery cell ends with a negative electrode sheet.
[0008] Furthermore, the lithium-rich electrode sheets are provided on both sides of the tail of the negative electrode sheet of the battery cell.
[0009] Furthermore, the thickness of the lithium-rich electrode is 1-100 μm.
[0010] Furthermore, the lithium-rich electrode sheet and the negative electrode sheet are isolated from each other by a non-porous insulating membrane.
[0011] Furthermore, the thickness of the non-porous insulating membrane is 1-10 μm.
[0012] Furthermore, the laminated battery core and the lithium-rich pole pieces located on both sides of the laminated battery core are packaged together in an aluminum-plastic film.
[0013] Furthermore, the three-electrode electrochemical device is provided with a negative electrode lithium replenishing module;
[0014] The third electrode tab and the negative electrode construct a current path to form the negative electrode lithium replenishing module.
[0015] Furthermore, the three-electrode electrochemical device is provided with a positive electrode lithium replenishing module;
[0016] The third electrode tab and the positive electrode construct a current path to form the positive electrode lithium replenishing module.
[0017] In a second aspect, a circuit system comprises the three-electrode electrochemical device described in any one of the above items.
[0018] Compared with the prior art, the utility model has the following beneficial effects:
[0019] The three-electrode electrochemical device provided by the utility model can construct a current path between the third electrode and the negative electrode in the formation stage, so that lithium can be replenished to the negative electrode, reducing the loss of the positive electrode active lithium in the process of forming a solid electrolyte film on the surface of the negative electrode in the formation stage; in the circulation stage, the third electrode and the positive electrode can construct a current path, so that lithium can be replenished to the positive electrode active material and the capacity of the battery cell can be restored. In short, the three-electrode electrochemical device of the utility model is simple to operate, adapted to the existing lithium battery process, and can realize quantitative lithium replenishment of the battery cell in the formation stage and the circulation stage, so as to effectively maintain the energy density and cycle stability of the battery cell.
[0020] The circuit system provided by the present invention has the same advantages as the above-mentioned three-electrode electrochemical device, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0022] Figure 1 A schematic diagram of the internal structure of a three-electrode electrochemical device provided in one embodiment of the utility model;
[0023] Figure 2 A schematic diagram of the external structure of a three-electrode electrochemical device provided in one embodiment of the utility model;
[0024] Figure 3 A schematic diagram of lithium replenishment of a three-electrode electrochemical device in a formation stage provided in one embodiment of the utility model;
[0025] Figure 4 A schematic diagram of lithium replenishment during the cycle of a three-electrode electrochemical device provided in one embodiment of the utility model.
[0026] Icons: 1-lithium-rich electrode; 2-porous insulating diaphragm; 3-negative electrode; 4-diaphragm; 5-positive electrode; 6-positive electrode tab; 7-negative electrode tab; 8-third tab; 9-negative electrode lithium replenishing module; 10-positive electrode lithium replenishing module. DETAILED DESCRIPTION
[0027] The technical solution of the utility model will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0028] The utility model provides a three-electrode electrochemical device, comprising a laminated battery core, lithium-rich pole pieces located on both sides of the laminated battery core, and a third pole lug;
[0029] The lithium-rich pole pieces on both sides of the laminated battery cell are welded to each other and lead out the third pole ear.
[0030] The three-electrode electrochemical device provided by the utility model can construct a current path between the third electrode and the negative electrode in the formation stage, so that lithium can be replenished to the negative electrode, reducing the loss of active lithium of the positive electrode in the process of forming a solid electrolyte film on the surface of the negative electrode in the formation stage; in the circulation stage, the third electrode can construct a current path with the positive electrode, so that lithium can be replenished to the positive electrode active material and the capacity of the battery cell can be restored.
[0031] In summary, the three-electrode electrochemical device of the utility model is simple to operate, is compatible with existing lithium battery processes, and can achieve quantitative lithium replenishment of the battery cell in the formation stage and the cycle stage, thereby effectively maintaining the energy density and cycle stability of the battery cell.
[0032] In a preferred embodiment, the structure of the laminated battery cell may be terminated with a negative electrode sheet.
[0033] The utility model adopts a battery cell prepared by stacking sheets as the main battery cell structure, which ends with a negative electrode sheet. Lithium-rich electrodes are introduced on both sides of the negative electrode of the battery cell. The lithium-rich electrodes on both sides are welded to each other and lead out a third electrode ear. The lithium-rich electrode sheet and the third electrode ear can be connected by welding.
[0034] The internal structure diagram of the three-electrode electrochemical device of the utility model is shown in Figure 1 A battery cell prepared by stacking sheets is used as the main battery cell structure, and the main battery cell structure ends with a negative electrode sheet 3. Lithium-rich electrodes 1 are introduced on both sides of the negative electrode of the main battery cell. The material of the lithium-rich electrode sheet 1 can be a pure lithium sheet, a lithium-copper composite sheet, and lithium powder. A non-porous insulating diaphragm 2 can be used to isolate the lithium-rich electrode sheet 1 from the negative electrode sheet 3, and a diaphragm 4 can be used to isolate the negative electrode sheet 3 from the positive electrode sheet 5.
[0035] In a preferred embodiment, the thickness of the lithium-rich electrode 1 may be 1-100 μm.
[0036] In a preferred embodiment, the thickness of the non-porous insulating membrane 2 may be 1-10 μm.
[0037] In a preferred embodiment, the laminated battery core and the lithium-rich pole pieces located on both sides of the laminated battery core can be packaged together in an aluminum-plastic film.
[0038] The utility model introduces lithium-rich pole pieces on both sides of the laminated battery cell, welds the lithium-rich pole pieces to the third pole ear, and packages them together with the original battery cell structure in an aluminum-plastic film to form a three-pole ear battery cell. Because the lithium supplement structure is integrated inside the battery cell, there is no need to remove the lithium supplement structure after formation.
[0039] In a preferred embodiment, a negative electrode lithium replenishment module is provided on the three-electrode electrochemical device, and the third electrode and the negative electrode form a current path to form the negative electrode lithium replenishment module;
[0040] A positive electrode lithium replenishing module is provided on the three-electrode electrochemical device, and the third electrode and the positive electrode form a current path to form the positive electrode lithium replenishing module.
[0041] The utility model utilizes an external circuit system, which can not only quantitatively supplement lithium to the negative electrode in the formation stage, but also quantitatively supplement lithium to the positive electrode in the circulation stage.
[0042] In summary, the utility model integrates the electrochemical lithium replenishment structure into the soft-pack battery. Through the negative electrode lithium replenishment module, the negative electrode can be replenished with lithium in the formation stage, thereby alleviating the loss of active lithium caused by the formation of a solid electrolyte film on the surface of the negative electrode; and through the positive electrode lithium replenishment module, the positive electrode can be replenished with lithium in the circulation stage, thereby increasing the gram capacity of the positive electrode active material and alleviating the degradation of the positive electrode structure.
[0043] Example 1
[0044] A three-electrode electrochemical device comprises a laminated battery core, lithium-rich electrodes located on both sides of the laminated battery core, and a third electrode;
[0045] The laminated battery cell and the lithium-rich pole pieces on both sides of the laminated battery cell are encapsulated together in an aluminum-plastic film;
[0046] Among them, the lithium-rich pole pieces on both sides of the stacked battery cell are welded to each other and lead out the third pole lug;
[0047] The internal structure diagram of the three-electrode electrochemical device is shown in Figure 1 , a battery cell prepared by stacking sheets is used as the main battery cell structure, the main battery cell structure ends with a negative electrode sheet 3, lithium-rich electrodes 1 are introduced on both sides of the negative electrode end of the main battery cell, the thickness of the lithium-rich electrode sheet 1 is 50 μm, the material of the lithium-rich electrode sheet 1 is a lithium-copper composite sheet, and the lithium-rich electrode sheet 1 is isolated from the negative electrode sheet 3 by a non-porous insulating diaphragm 2, and the thickness of the non-porous insulating diaphragm 2 is 1 μm;
[0048] At the same time, the negative electrode sheet 3 and the positive electrode sheet 5 are isolated by a separator 4;
[0049] The external structure diagram of the three-electrode electrochemical device is shown in Figure 2 A positive electrode tab 6 and a negative electrode tab 7 are arranged on the outside, and the lithium-rich electrode sheet 1 is connected to the third tab 8 by welding.
[0050] In the three-electrode electrochemical device provided in this embodiment, when replenishing lithium in the formation stage, the negative electrode tab 7 is connected to the third electrode tab 8 through the external circuit negative electrode lithium replenishing module 9. Figure 3 , discharge treatment is carried out, the discharge rate I1 is set to 0.1C or less, the discharge time t1 is adjusted according to the lithium replenishment amount q1 and the battery cell capacity Q1, t1 = q1 / (Q1*I1); after the discharge is completed, the constant voltage time T1 hour is required at the current voltage V1; lithium ions are released through the lithium-rich electrode sheet 1 to participate in the construction of the solid electrolyte layer on the surface of the negative electrode, reducing the subsequent formation consumption of active lithium from the positive electrode.
[0051] The three-electrode electrochemical device provided in this embodiment disconnects the circuit between the positive and negative electrodes when replenishing lithium in the cycle stage, and connects the positive electrode tab 6 to the third electrode tab 8 through the external circuit positive electrode lithium replenishment module 10. Figure 4 , discharge treatment is carried out, the discharge rate I2 is set to 0.1C or less, the discharge time t2 is adjusted according to the lithium replenishment amount q2 and the battery cell capacity Q2, t2 = q2 / (Q2*I2); after the discharge is completed, the constant voltage time T2 hours is required at the current voltage V1; lithium ions are released through the lithium-rich electrode sheet 1 to make up for the active lithium consumed by the positive electrode active material during multiple cycles, which is beneficial to improve the positive electrode capacity and structural stability.
[0052] It can be seen that the three-electrode electrochemical device provided in this embodiment can achieve quantitative lithium replenishment of the battery cell during the formation and cycle process, thereby reducing the loss of active lithium inside the battery cell and improving the energy density and cycle life of the battery cell.
[0053] Comparative Example 1
[0054] The difference between this comparative example and Example 1 is that in this comparative example, the lithium-rich electrode sheet 1 is introduced only on one side of the negative electrode tail of the main battery cell, while the lithium-rich electrode sheet 1 is not introduced on the other side of the negative electrode tail;
[0055] The rest is the same as in Example 1, and a three-electrode electrochemical device is obtained.
[0056] Compared with Example 1, the defect of the three-electrode electrochemical device of this comparative example is that the lithium replenishment electrode plate cannot uniformly replenish lithium to the battery cell on one side. The side with the lithium replenishment electrode plate can achieve excellent lithium replenishment effect, and the lithium replenishment amount on the side without the lithium replenishment electrode plate is low and uneven.
[0057] Comparative Example 2
[0058] The difference between this comparative example and Example 1 is that in this comparative example, the lithium-rich electrode sheet 1 is not arranged on both sides of the laminated battery cell, but the lithium-rich electrode sheet 1 is arranged in the middle of the laminated battery cell;
[0059] The rest is the same as in Example 1, and a three-electrode electrochemical device is obtained.
[0060] Compared with Example 1, the defect of the three-electrode electrochemical device of this comparative example is that the battery cell cannot be charged and discharged.
[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.
Claims
1. A three-electrode electrochemical device, characterized in that: It includes a laminated battery core, lithium-rich pole pieces located on both sides of the laminated battery core, and a third pole ear; Wherein, the lithium-rich pole pieces located on both sides of the laminated battery core are welded to each other and lead out the third pole lug.
2. The three-electrode electrochemical device according to claim 1, characterized in that: The structure of the laminated battery cell ends with a negative electrode sheet.
3. The three-electrode electrochemical device according to claim 2, characterized in that: The lithium-rich electrode sheets are arranged on both sides of the negative electrode sheet of the battery cell.
4. The three-electrode electrochemical device according to claim 3, characterized in that: The thickness of the lithium-rich electrode is 1-100 μm.
5. The three-electrode electrochemical device according to claim 3, characterized in that: The lithium-rich electrode sheet is isolated from the negative electrode sheet by a non-porous insulating diaphragm.
6. The three-electrode electrochemical device according to claim 5, characterized in that: The non-porous insulating membrane has a thickness of 1-10 μm.
7. The three-electrode electrochemical device according to any one of claims 1 to 6, characterized in that: The laminated battery core and the lithium-rich pole pieces located on both sides of the laminated battery core are packaged together in an aluminum-plastic film.
8. The three-electrode electrochemical device according to any one of claims 1 to 6, characterized in that: The three-electrode electrochemical device is provided with a negative electrode lithium replenishing module; The third electrode tab and the negative electrode construct a current path to form the negative electrode lithium replenishing module.
9. The three-electrode electrochemical device according to any one of claims 1 to 6, characterized in that: The three-electrode electrochemical device is provided with a positive electrode lithium replenishing module; The third electrode tab and the positive electrode construct a current path to form the positive electrode lithium replenishing module.
10. A circuit system, characterized in that: A three-electrode electrochemical device comprising any one of claims 1-9.