Winding battery cell and cylindrical battery
By adding a liquid storage layer to the positive electrode plate, the gap problem caused by the protruding positive electrode tab is solved, which improves the ion transport efficiency and safety of the battery and ensures the performance of the battery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-31
- Publication Date
- 2026-03-31
Smart Images
Figure CN224067876U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery energy storage, and in particular to a wound cell and a cylindrical battery. Background Technology
[0002] Currently, cylindrical batteries are manufactured by winding the positive and negative electrode sheets and separator into a casing. Typically, a cylindrical battery consists of a positive electrode sheet, a separator, and a negative electrode sheet. The positive electrode sheet has a positive tab, and the negative electrode sheet has a negative tab. These tabs are usually welded to the current collectors of the corresponding electrodes and covered with high-temperature adhesive. However, the thickness of the overlapping area of the tabs and the high-temperature adhesive is 110-120 μm, higher than other areas on the positive electrode sheet. This makes the overlapping area prone to bulging, preventing the stacked positive and negative electrode sheets from being tightly connected at the bulging edges. Gaps form between the positive and negative electrode sheets at these bulges, preventing the electrolyte from fully wetting the electrodes and increasing the internal resistance at the tab weld. Both of these phenomena hinder ion transport at the tabs, reducing the battery's capacity. Sodium ions adhere to the surface of the negative electrode sheet, causing "sodium deposition," which poses a safety hazard to the battery.
[0003] Therefore, how to solve the problem of gaps between positive and negative electrode plates caused by protruding positive electrode tabs, which obstructs ion transport in the gaps, reduces battery capacity in actual use, and poses safety hazards, is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content
[0004] The purpose of this invention is to provide a wound cell and a cylindrical battery to solve the problem in the prior art where the positive electrode tab protrudes, causing a gap between the positive and negative electrode plates, which obstructs ion transport in the gap, reduces battery capacity in actual use, and poses a safety hazard.
[0005] To solve the above-mentioned technical problems, this utility model provides a wound battery cell, including a positive electrode, a negative electrode, a separator, and a first liquid storage layer;
[0006] The positive electrode, the separator, and the negative electrode are stacked in sequence to form a cell composite layer; the cell composite layer is wound to obtain the wound cell;
[0007] The first liquid storage layer is stacked in the cell composite layer;
[0008] In the wound cell, the projection of the first liquid storage layer onto the positive electrode overlaps with the positive electrode tab of the positive electrode.
[0009] Optionally, in the wound cell, the first liquid storage layer includes a plurality of liquid storage units;
[0010] Multiple liquid storage units are spaced apart along the long axis of the cell composite layer, and the projections of all liquid storage units on the positive electrode sheet in the wound cell overlap with the positive electrode tab.
[0011] Optionally, in the wound cell, the cell composite layer includes continuous stacked regions;
[0012] The first liquid storage layer is only disposed in the stacked area.
[0013] Optionally, in the wound battery cell, the first liquid storage layer is a liquid-absorbing diaphragm layer.
[0014] Optionally, in the wound battery cell, the liquid-absorbing diaphragm layer and the diaphragm are integrally formed.
[0015] Optionally, the wound cell further includes a surface coating layer;
[0016] The surface coating layer is disposed on the outer surface of the wound cell.
[0017] Optionally, in the wound battery cell, the surface coating layer includes at least one of a second liquid storage layer, a high-temperature adhesive layer, and a rubber layer.
[0018] Optionally, in the wound cell, the thickness of the surface coating layer is not less than 12 micrometers.
[0019] A cylindrical battery, the cylindrical battery comprising a cylindrical casing and any of the wound cells described above.
[0020] Optionally, in the cylindrical battery, the wound cell includes a surface coating layer;
[0021] The filling rate of the wound battery cell when it is placed into the cylindrical housing is not less than 98%.
[0022] This invention provides a battery cell comprising a positive electrode, a negative electrode, a separator, and a first electrolyte storage layer. The positive electrode, the separator, and the negative electrode are sequentially stacked to form a battery cell composite layer. The battery cell composite layer is wound to obtain a wound battery cell. The first electrolyte storage layer is stacked within the battery cell composite layer. In the wound battery cell, the projection of the first electrolyte storage layer onto the positive electrode overlaps with the positive electrode tab of the positive electrode. In this invention, a first electrolyte storage layer for storing electrolyte is added at the position of the positive electrode tab. Utilizing the excellent electrolyte absorption and retention capabilities of the first electrolyte storage layer, the gap caused by the protrusion of the positive electrode tab has relatively more electrolyte than other tightly fitted areas, facilitating sodium ion transport and reducing sodium precipitation. This ensures battery capacity during cyclic use while avoiding potential safety hazards. This invention also provides a cylindrical battery with the above-mentioned beneficial effects. Attached Figure Description
[0023] To more clearly illustrate the technical solutions of the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 A schematic diagram of a specific embodiment of the wound battery cell provided by this utility model;
[0025] Figure 2 A schematic diagram of the structure of the wound battery cell before winding, according to a specific embodiment of the present invention;
[0026] Figure 3 A schematic diagram of the structure before winding of another specific embodiment of the wound battery cell provided by this utility model;
[0027] Figure 4 A schematic diagram of another specific embodiment of the wound battery cell provided by this utility model;
[0028] Figure 5 A schematic diagram of another specific embodiment of the wound battery cell provided by this utility model;
[0029] Figure 6 This is a schematic diagram of a specific embodiment of the cylindrical battery provided by this utility model.
[0030] Figure label:
[0031] 10-Positive electrode sheet; 11-Positive electrode tab; 20-Negative electrode sheet; 30-Separator; 40-First liquid storage layer; 41-Liquid storage unit; 50-Surface coating layer; 60-Cylindrical shell. Detailed Implementation
[0032] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0033] The core of this utility model is to provide a wound battery cell, the structural schematic diagram of one specific embodiment of which is shown below. Figure 1As shown, this is referred to as Specific Implementation Method 1, which includes a positive electrode 10, a negative electrode 20, a diaphragm 30, and a first liquid storage layer 40.
[0034] The positive electrode 10, the separator 30, and the negative electrode 20 are stacked in sequence to form a cell composite layer; the cell composite layer is wound to obtain the wound cell;
[0035] The first liquid storage layer 40 is stacked in the cell composite layer;
[0036] In the wound cell, the projection of the first liquid storage layer 40 onto the positive electrode 10 overlaps with the positive electrode tab 11 of the positive electrode 10.
[0037] For reference Figure 2 , Figure 2 The diagram shows the structure of the unwound composite layer of the battery cell. It is clear that the area of the positive electrode tab 11 covered by the high-temperature adhesive protrudes from the positive electrode sheet 10. Figure 2 The first liquid storage layer 40 is located directly above the positive electrode tab 11, as shown in the schematic diagram after winding. Figure 1 As shown, it is important to note that Figure 1 In this process, the first liquid storage layer 40 is disposed on the side surface of the diaphragm 30 that is close to the negative electrode 20. In actual production, the first liquid storage layer 40 can also be disposed on the side surface of the diaphragm 30 that is close to the positive electrode 10.
[0038] In a preferred embodiment, the first liquid storage layer 40 includes a plurality of liquid storage units 41;
[0039] Multiple liquid storage units 41 are spaced apart along the long axis of the cell composite layer, and the projections of all liquid storage units 41 on the positive electrode sheet 10 in the wound cell overlap with the positive electrode tab 11.
[0040] For reference Figure 3 , Figure 3 The diagram shows the distribution of the liquid storage units 41 in the battery cell composite layer before winding, while the schematic diagram after winding is shown below. Figure 4 As shown, the first liquid storage layer 40 is dispersed into multiple liquid storage units 41. After winding, each of the battery cell composite layers overlaps above the positive electrode tab 11 (theoretically, a gap will be generated every time the battery cell composite layer passes above the positive electrode tab 11), and a corresponding liquid storage unit 41 exists, so that the electrolyte stored in the liquid storage layer can wet more gaps and further improve the ion transport effect.
[0041] Furthermore, the cell composite layer includes continuous stacked regions;
[0042] The first liquid storage layer 40 is only disposed in the stacked area.
[0043] In other words, the battery cell described in this preferred embodiment is disposed in only a single area, which can be referred to as Figure 1 Concentrating the first liquid storage layer 40 in one area can greatly reduce the difficulty of the process and improve production efficiency.
[0044] In one specific embodiment, the first liquid storage layer 40 is a liquid-absorbing diaphragm layer.
[0045] In other words, the first liquid storage layer 40 in this specific embodiment is a layer of the same material as the diaphragm 30, and is called the liquid-absorbing diaphragm layer. After the diaphragm 30 of the battery cell composite layer is cut into small pieces, the remaining diaphragm 30 material is cut into small pieces and set in the corresponding position as the first liquid storage layer 40, which can serve as the liquid-absorbing diaphragm layer. This can further reduce the production cost of the wound battery cell.
[0046] Furthermore, the liquid-absorbing diaphragm layer and the diaphragm 30 are integrally formed.
[0047] In other words, in this specific embodiment, the liquid-absorbing diaphragm layer and the diaphragm 30 are integrated. It can be considered that the diaphragm 30 is locally thickened, and the thickened area can be regarded as the composite area of the diaphragm 30 and the liquid-absorbing diaphragm layer. This reduces the installation difficulty of the first liquid storage layer 40 and avoids the yield reduction caused by the relative displacement between the first liquid storage layer 40 and the positive electrode 10 during the winding of the battery cell composite layer. At the same time, since there is no structure that needs to be aligned separately, the process difficulty of this utility model is greatly reduced and the production cost is reduced.
[0048] This invention provides a battery cell comprising a positive electrode 10, a negative electrode 20, a separator 30, and a first electrolyte storage layer 40. The positive electrode 10, the separator 30, and the negative electrode 20 are sequentially stacked to form a battery cell composite layer. The battery cell composite layer is wound to obtain a wound battery cell. The first electrolyte storage layer 40 is stacked within the battery cell composite layer. In the wound battery cell, the projection of the first electrolyte storage layer 40 onto the positive electrode 10 overlaps with the positive electrode tab 11 of the positive electrode 10. In this invention, a first electrolyte storage layer 40 for storing electrolyte is added at the position of the positive electrode tab 11. Utilizing the excellent electrolyte absorption and retention capabilities of the first electrolyte storage layer 40, the gap caused by the protrusion of the positive electrode tab 11 has relatively more electrolyte than other tightly fitted areas, facilitating sodium ion transport, reducing sodium precipitation, and ensuring battery capacity during cyclic use while avoiding potential safety hazards.
[0049] Based on the first specific embodiment, the wound battery cell is further improved to obtain the second specific embodiment, the corresponding structural schematic diagram of which is shown below. Figure 5 As shown, it includes a positive electrode 10, a negative electrode 20, a separator 30, and a first liquid storage layer 40;
[0050] The positive electrode 10, the separator 30, and the negative electrode 20 are stacked in sequence to form a cell composite layer; the cell composite layer is wound to obtain the wound cell;
[0051] The first liquid storage layer 40 is stacked in the cell composite layer;
[0052] In the wound cell, the projection of the first liquid storage layer 40 onto the positive electrode 10 overlaps with the positive electrode tab 11 of the positive electrode 10;
[0053] It also includes a surface coating layer 50;
[0054] The surface coating layer 50 is disposed on the outer surface of the wound cell.
[0055] The difference between this specific embodiment and the above specific embodiment is that a surface wrapping layer 50 is added to the outer side of the wound battery cell in this specific embodiment. The rest of the structure is the same as the above specific embodiment, and will not be described in detail here.
[0056] In this specific embodiment, a surface coating layer 50 is added to the outer surface of the wound cell, which further increases the diameter of the cylindrical wound cell and further reduces the gap between it and the cylindrical shell 60 during packaging. After the electrolyte is poured into the cylindrical shell 60, the wound cell absorbs the liquid and expands. The tight fit between the wound cell and the cylindrical shell 60 suppresses the expansion of the wound cell. This is equivalent to the cylindrical shell 60 applying greater pressure to the wound cell, forcing the separator 30 and the first liquid storage layer 40 to fill the gap around the positive electrode tab 11, further improving ion mobility, while not affecting the expansion caused by subsequent battery cycles.
[0057] In a preferred embodiment, the surface coating layer 50 includes at least one of a second electrolyte storage layer, a high-temperature adhesive layer, and a rubber layer. Besides increasing the diameter of the wound battery cell, the surface coating layer 50 can also be given certain functionalities. For example, if the surface coating layer 50 is the second electrolyte storage layer, it gives the surface coating layer 50 additional electrolyte absorption capacity, providing a larger energy storage space for the battery and increasing battery capacity. Similarly, the second electrolyte storage layer will expand after absorbing liquid, providing additional pressure and compressing the gap at the positive electrode tab 11. If the surface coating layer 50 is the high-temperature adhesive layer or the rubber layer, it can improve the elasticity of the surface coating layer 50 and provide greater pressure. Of course, other materials can also be selected as the surface coating layer 50 according to actual conditions; this utility model does not limit this.
[0058] Furthermore, the thickness of the surface coating layer 50 is not less than 12 micrometers. The above parameter range is the optimal range obtained through a large number of theoretical calculations and actual tests. If the surface coating layer 50 is less than 12 micrometers thick, it cannot provide a large pressure to compress the diaphragm 30 and the first liquid storage layer 40 to reduce the gap at the positive electrode tab 11 after the wound cell absorbs liquid and expands.
[0059] This utility model also provides a cylindrical battery, the structural schematic diagram of one specific embodiment of which is shown below. Figure 6 As shown, this is referred to as Specific Embodiment Three. The cylindrical battery includes a cylindrical casing 60 and any of the above-described wound cells.
[0060] The cylindrical battery in this specific embodiment corresponds to the wound battery cell mentioned above. For specific technical details, please refer to the previous text. This utility model will not be described in detail here.
[0061] In a preferred embodiment, the wound battery cell includes a surface coating layer 50;
[0062] The filling rate of the wound battery cell when it is placed into the cylindrical housing 60 is not less than 98%.
[0063] The above specific embodiments define the filling rate when the wound battery cell is placed into the cylindrical housing 60. Here, it refers to the filling rate when the wound battery cell is placed into the cylindrical housing 60 without electrolyte injection. In the relevant prior art, the filling rate is generally around 91%, while this preferred embodiment increases the filling rate to facilitate the cylindrical housing 60 to apply pressure to the wound battery cell to compress the gap after liquid absorption and expansion, thereby improving ion flow.
[0064] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.
[0065] It should be noted that, in this specification, relational terms such as "first" and "second" are used only 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.
[0066] The wound battery cell and cylindrical battery provided by this utility model have been described in detail above. Specific examples have been used to illustrate the principle and implementation of this utility model. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core idea of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of this utility model.
Claims
1. A wound cell, characterized by, The positive electrode sheet, the separator, and the negative electrode sheet are sequentially stacked to form an electrode core composite layer, and the electrode core composite layer is wound to form the wound electrode core. The first liquid storage layer is stacked in the electrode core composite layer. In the wound electrode core, a projection of the first liquid storage layer on the positive electrode sheet overlaps with the positive electrode tab. The first liquid storage layer includes a plurality of liquid storage units.
2. The wound cell core of claim 1, wherein, The plurality of liquid storage units are arranged at intervals in a long axis direction of the electrode core composite layer, and projections of all the liquid storage units on the positive electrode sheet overlap with the positive electrode tab in the wound electrode core. The electrode core composite layer includes a continuous stacking area.
3. The wound cell according to claim 1, wherein The first liquid storage layer is arranged only in the stacking area. The first liquid storage layer is a liquid-absorbing separator layer.
4. The wound cell according to claim 1, wherein The liquid-absorbing separator layer and the separator are integrally formed.
5. The wound cell according to claim 4, wherein The surface wrapping layer includes at least one of a second liquid storage layer, a high-temperature adhesive layer, and a rubber layer.
6. The wound cell according to any one of claims 1 to 5, wherein The thickness of the surface wrapping layer is not less than 12 microns. The cylindrical battery includes a cylindrical shell and the wound electrode core according to any one of claims 1 to 8.
7. The wound cell according to claim 6, wherein The wound electrode core includes a surface wrapping layer.
8. The wound cell according to claim 6, wherein When the wound electrode core is placed in the cylindrical shell, the filling rate is not less than 98%.
9. A cylindrical battery, characterized by 10. The cylindrical battery of claim 9, wherein the positive electrode is a lithium cobalt oxide electrode.