Battery structure applied to high-capacity sodium ion battery

Abstract

The battery structure comprises a positive plate and a negative plate, the positive plate and the negative plate are isolated from each other through a diaphragm, the size of the negative plate is larger than that of the positive plate, the negative plate is provided with first gaps which are arranged at intervals along the length direction of the negative plate, and the first gaps are arranged at intervals along the length direction of the negative plate. The positive plate is provided with second gaps arranged at intervals along the length direction of the positive plate, the positions of the first gaps and the second gaps correspond to each other, and the positive plate is also provided with a plurality of third gaps between the second gaps. The battery structure applied to the high-capacity sodium-ion battery has the characteristics of good electrolyte penetration wettability, small electrolyte injection amount and high process applicability.

Description

Technical Field

[0001] The utility model relates to the technical field of sodium-ion batteries, and specifically refers to a battery structure applied to large-capacity sodium-ion batteries. Background Technique

[0002] Sodium-ion batteries are emerging battery technologies, and their applications in the energy storage field are receiving increasing attention. Their advantages are mainly reflected in the following aspects:

[0003] For example, in terms of the abundance of raw materials, sodium is an element widely present in the earth's crust, especially with extremely high content in seawater. Compared with lithium, sodium has a more abundant reserve and is more evenly distributed, which makes sodium-ion batteries have stronger sustainability and lower costs in terms of resource acquisition. It does not need to rely on scarce mineral deposits such as lithium or cobalt, thus reducing the risk of resource depletion and the uncertainty brought by market price fluctuations.

[0004] For example, in terms of cost-effectiveness, due to the abundance of sodium and relatively low extraction costs, the production cost of sodium-ion batteries is usually lower than that of lithium-ion batteries. This cost advantage makes sodium-ion batteries more attractive in large-scale energy storage systems. For example, when used for grid balancing and the storage of renewable energy (such as wind energy and solar energy), the lower material cost can make the entire system more economical and efficient.

[0005] For example, in terms of environmental friendliness, sodium-ion batteries have relatively less impact on the environment during production and recycling. The extraction and processing of sodium are relatively simple and do not involve the mining of rare metals that cause great damage to the environment. In addition, the recycling process of sodium-ion batteries is also relatively simple, which helps to reduce the burden of waste on the environment, and this is particularly important in the context of emphasizing sustainable development today.

[0006] For example, in terms of safety, sodium-ion batteries exhibit characteristics superior to lithium-ion batteries. Sodium-ion batteries are more stable in high-temperature environments and are not prone to hazards such as thermal runaway. Lithium-ion batteries have a risk of catching fire or exploding during charging or short-circuiting, while the risk of sodium-ion batteries is significantly reduced due to their electrochemical properties.

[0007] For example, in terms of cycle life and durability, sodium-ion batteries show good stability during charge and discharge cycles, especially in the case of deep discharge. Research shows that sodium-ion batteries have relatively high charge and discharge efficiency and long cycle life. This is of great significance in application scenarios with frequent charge and discharge, such as in power dispatching and renewable energy integration, and can effectively cope with large-scale power demand and supply fluctuations.

[0008] In terms of improving energy density, although the energy density of sodium-ion batteries is relatively lower than that of lithium-ion batteries at present, with the continuous progress of technology, the energy density of sodium-ion batteries is gradually increasing. The research and development of new materials and the optimization of battery design have continuously tapped the potential of sodium-ion batteries in energy storage, enabling them to better meet the needs of industries such as large-scale energy storage power stations, efficient power grids, and electric vehicles.

[0009] In terms of adapting to diverse applications, due to its unique characteristics, sodium-ion batteries are particularly suitable for large-scale and low-power energy storage applications, especially as load regulation and energy balance solutions in the power system. Different from lithium-ion batteries that are suitable for applications with high energy density and high-power output, sodium-ion batteries can better meet the needs of grid regulation and large-scale energy storage.

[0010] Based on this, sodium-ion batteries are gradually developing towards large-capacity and even ultra-large-capacity. Taking cylindrical batteries as an example, domestic enterprises successfully developed ultra-large cylindrical energy storage sodium batteries in 2023, with a diameter of 120mm - 200mm and a length of 300mm - 1200mm, and the monomer capacity covering 1 kWh - 10 kWh. The product applications focus on energy storage, including household energy storage, industrial and commercial energy storage, energy storage power stations and other fields.

[0011] However, the production of large-capacity or ultra-large-capacity batteries necessarily requires an increase in the area of the electrode sheets, an increase in the number of stacked layers or winding layers, and accordingly, problems of electrolyte penetration and wetting will occur. The penetration and wetting property of the electrolyte is a key factor affecting battery performance, especially in lithium-ion batteries, sodium-ion batteries, and other types of batteries. Penetration and wetting property refers to the wetting ability of the electrolyte on the electrode material, which directly affects the electrochemical reaction and overall performance of the battery. Summary of the Invention

[0012] The purpose of the present invention is to provide a battery structure applied to large-capacity sodium-ion batteries, which has the characteristics of good electrolyte penetration and wetting property, less electrolyte injection volume, and strong process applicability.

[0013] The present invention can be realized through the following technical solutions:

[0014] The present invention discloses a battery structure applied to large-capacity sodium-ion batteries, including a positive electrode sheet and a negative electrode sheet. The positive electrode sheet and the negative electrode sheet are mutually isolated by a separator. The size of the negative electrode sheet is larger than that of the positive electrode sheet. The negative electrode sheet is provided with first gaps arranged at intervals along the length direction of the negative electrode sheet, and the positive electrode sheet is provided with second gaps arranged at intervals along the length direction of the positive electrode sheet. The positions of the first gaps and the second gaps correspond to each other. The positive electrode sheet is also provided with a plurality of third gaps between the second gaps.

[0015] Furthermore, the positive electrode sheet includes a positive electrode current collector and a positive electrode material layer coated on the surface of the positive electrode current collector. The positive electrode current collector is coated with a positive electrode material layer having a thickness lower than the normal value in the third gap. This not only realizes the electrolyte penetration channel but also fully utilizes the space to improve the energy density of the battery.

[0016] Furthermore, the positive electrode material layer at the third gap is coated on the positive electrode current collector in a stepped or inclined stepped recessed manner. By forming a stepped or inclined stepped shape, it is convenient for the electrolyte to penetrate into the interior of the electrode sheet.

[0017] Furthermore, the negative electrode sheet includes a negative electrode current collector and a negative electrode material layer coated on the surface of the negative electrode current collector. The negative electrode current collector is not coated with a negative electrode material layer having a thickness lower than the normal value at the first gap. This not only forms an electrolyte penetration channel but also fully utilizes the space of the winding core to improve the energy density.

[0018] Furthermore, the positive electrode current collector is coated with a positive electrode material layer having a thickness lower than the normal value at the second gap. This not only forms an electrolyte penetration channel but also fully utilizes the space of the winding core to improve the energy density.

[0019] Furthermore, the size of the first gap is smaller than that of the second gap, effectively forming an excessive area of the negative electrode relative to the positive electrode and avoiding potential safety hazards caused by the precipitation of sodium metal.

[0020] Furthermore, the positive electrode current collector and the negative electrode current collector are aluminum foil, aluminum mesh, copper foil or copper mesh, and different current collector types can be flexibly selected according to actual needs.

[0021] Furthermore, the positive electrode material layer of the positive electrode sheet is a polyanion material layer, a layered oxide material layer or a Prussian blue material layer, meeting the usage requirements of different positive electrode materials.

[0022] Furthermore, the negative electrode material layer is a hard carbon material layer, a soft carbon material layer or an alloy negative electrode material layer, meeting the applicability requirements of different negative electrode materials.

[0023] Furthermore, the sodium-ion battery is formed by winding or stacking. For the sodium-ion battery formed by winding, the first gap and the second gap correspond radially along the winding core. For the sodium-ion battery formed by stacking, the first gap and the second gap correspond vertically, forming a uniformly distributed electrolyte penetration channel.

[0024] The battery structure of the present utility model applied to a large-capacity sodium-ion battery has the following beneficial effects:

[0025] First, the electrolyte penetration and wettability are good. By setting the first gap, the second gap, and the third gap, an electrolyte penetration and infiltration channel is formed between the large-size and multi-layer battery electrode sheets, facilitating the uniform penetration of the electrolyte into the interior of the electrode sheet and ensuring the conductivity of the battery.

[0026] Second, the amount of electrolyte used is small. By setting the first gap, the second gap, and the third gap, the electrolyte forms a permeation and infiltration channel through the above gaps and enters the interior of the electrolyte, eliminating the need to achieve electrolyte permeation by using an excessive amount during the electrode liquid injection process, thus effectively reducing the amount of electrolyte injection.

[0027] Third, it has strong process applicability. The battery structure of the present invention only requires simple structural design on the positive electrode sheet and the negative electrode sheet, which can be achieved either through the coating process during coating or through scraping treatment after coating. The processes of other battery manufacturing are not different from those of the prior art, showing good applicability. Description of the Drawings

[0028] Appendix Figure 1 It is a schematic diagram of the positive electrode sheet structure of a battery structure applied to a large-capacity sodium-ion battery according to the present invention;

[0029] Appendix Figure 2 It is a schematic diagram of the negative electrode sheet structure of a battery structure bubble applied to a large-capacity sodium-ion battery according to the present invention;

[0030] The marks in the drawings include: 100, positive electrode sheet; 110, positive current collector; 120, positive electrode material layer; 130, second gap; 140, third gap; 200, negative electrode sheet; 210, negative current collector; 220, negative electrode material layer; 230, first gap. Detailed Embodiments

[0031] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the products of the present invention will be further described in detail below with reference to the embodiments.

[0032] As Figure 1-2 shown, the present invention discloses a battery structure applied to a large-capacity sodium-ion battery, including a positive electrode sheet 100 and a negative electrode sheet 200. The positive electrode sheet 100 and the negative electrode sheet 200 are isolated from each other by a separator. The size of the negative electrode sheet 200 is larger than that of the positive electrode sheet 100. The negative electrode sheet 200 is provided with a first gap 230 arranged at intervals along the length direction of the negative electrode sheet. The positive electrode sheet 100 is provided with a second gap 130 arranged at intervals along the length direction of the positive electrode sheet. The positions of the first gap 240 and the second gap 130 correspond to each other. The positive electrode sheet 100 is further provided with a plurality of third gaps 140 between the second gaps 130. Although only one third gap is shown in Figure 1 , in practice, it can be flexibly set according to needs.

[0033] As Figure 1As shown in the figure. The positive electrode sheet 100 includes a positive electrode current collector 110 and a positive electrode material layer 120 coated on the surface of the positive electrode current collector 110. The positive electrode current collector 110 is coated with a positive electrode material layer 120 having a thickness lower than the normal value at the third gap 140. Specifically, for the convenience of the electrolyte, the positive electrode material layer at the third gap 140 is coated on the positive electrode current collector 110 in a stepped or inclined stepped recessed manner. Similarly, the positive electrode current collector 110 is coated with a positive electrode material layer having a thickness lower than the normal value at the second gap 130.

[0034] As Figure 2 As shown in the figure, the negative electrode sheet 200 includes a negative electrode current collector 210 and a negative electrode material layer 220 coated on the surface of the negative electrode current collector 210. The negative electrode current collector 210 is not coated with a negative electrode material layer having a thickness lower than the normal value at the first gap 230.

[0035] In the present utility model, in order to ensure the safety of the battery by making the negative electrode excessive, the size of the first gap is smaller than that of the second gap.

[0036] In the present utility model, there are no special restrictions on the materials. For example, the positive electrode current collector and the negative electrode current collector are aluminum foil, aluminum mesh, copper foil or copper mesh; for example, the positive electrode material layer of the positive electrode sheet is a polyanion material layer, a layered oxide material layer or a Prussian blue material layer; for example, the negative electrode material layer is a hard carbon material layer, a soft carbon material layer or an alloy negative electrode material layer.

[0037] In the present utility model, there are no special requirements for the process either. The sodium-ion battery is formed by winding or laminating. For the sodium-ion battery formed by winding, the first gap and the second gap correspond along the radial direction of the winding core. For the sodium-ion battery formed by laminating, the first gap and the second gap correspond up and down.

[0038] The above embodiments are only specific embodiments of the present utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present utility model, several deformations and improvements can be made, and these obvious replacement forms all belong to the protection scope of the present utility model.

Claims

1. A battery structure for a large-capacity sodium-ion battery, comprising a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet and the negative electrode sheet are separated from each other by a diaphragm, characterized in that: The size of the negative electrode sheet is larger than that of the positive electrode sheet. The negative electrode sheet is provided with first gaps spaced along the length direction of the negative electrode sheet, and the positive electrode sheet is provided with second gaps spaced along the length direction of the positive electrode sheet. The positions of the first gap and the second gap correspond to each other, and the positive electrode sheet is further provided with a plurality of third gaps between the second gaps.

2. The battery structure for large-capacity sodium-ion batteries according to claim 1, characterized in that: The positive electrode sheet comprises a positive electrode current collector and a positive electrode material layer coated on the surface of the positive electrode current collector. The positive electrode current collector is coated with a positive electrode material layer having a thickness lower than a normal value in the third gap.

3. The battery structure for large-capacity sodium-ion batteries according to claim 2, characterized in that: The positive electrode material layer at the third gap is concavely coated on the positive electrode current collector in a step-like or inclined step-like manner.

4. The battery structure for large-capacity sodium-ion batteries according to claim 3 is characterized in that: The negative electrode sheet comprises a negative electrode current collector and a negative electrode material layer coated on the surface of the negative electrode current collector, and the negative electrode current collector is not coated with a negative electrode material layer having a thickness lower than a normal value at the first gap.

5. The battery structure for large-capacity sodium-ion batteries according to claim 4, characterized in that: The positive electrode current collector is coated with a positive electrode material layer having a thickness lower than a normal value in the second gap.

6. The battery structure for large-capacity sodium-ion batteries according to claim 5, characterized in that: The first gap is smaller in size than the second gap.

7. The battery structure for large-capacity sodium-ion batteries according to claim 6, characterized in that: The positive electrode current collector and the negative electrode current collector are aluminum foil, aluminum mesh, copper foil or copper mesh.

8. The battery structure for large-capacity sodium-ion batteries according to claim 7, characterized in that: The positive electrode material layer of the positive electrode sheet is a polyanion material layer, a layered oxide material layer or a Prussian blue material layer.

9. The battery structure for large-capacity sodium-ion batteries according to claim 8, characterized in that: The negative electrode material layer is a hard carbon material layer, a soft carbon material layer or an alloy negative electrode material layer.

10. The battery structure for large-capacity sodium-ion batteries according to claim 9, characterized in that: The sodium ion battery is formed by winding or stacking. The first gap and the second gap of the sodium ion battery formed by winding correspond to each other along the radial direction of the winding core, and the first gap and the second gap of the sodium ion battery formed by stacking correspond to each other up and down.

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