Capillary tube array structure, lithium ion battery and electrolyte conduction method of lithium ion battery

Abstract

The invention provides a capillary tube array structure, a lithium ion battery and an electrolyte conduction method of the lithium ion battery. The capillary tube array structure is a hollow cylinder; the capillary tube array structure comprises a plurality of capillary tube units which are annularly distributed around the axis of the column body; each capillary unit comprises at least three capillary tubes with different inner diameters, and the inner wall of each capillary tube is subjected to lyophilic modification treatment. According to the capillary tube array structure, the lithium ion battery and the electrolyte conduction method of the lithium ion battery, disclosed by the invention, through cooperative cooperation of at least three capillary tubes with different inner diameters in each capillary tube unit, relatively high transmission of the electrolyte is realized, high-efficiency diffusion after transmission is also ensured, and the pain point of insufficient infiltration of the electrolyte at the top of a high-height battery is solved; the capillary tube array structure applied to the middle of the roll core also has a certain supporting effect, and collapse of a core layer in the middle of the roll core due to the expansion effect in the charge-discharge cycle process of the battery cell can be prevented.

Description

Technical Field

[0001] This disclosure relates to the field of lithium-ion battery technology, and in particular to a capillary array structure, a lithium-ion battery, and a method for electrolyte conduction. Background Technology

[0002] With the rapid development of electric vehicles and large-scale energy storage systems, lithium-ion batteries, especially large cylindrical batteries, are widely used due to their high energy density and flexible assembly. However, during long-term cycling, the electrolyte distribution inside the battery is uneven due to gravity, resulting in a significantly larger electrolyte concentration at the bottom than at the top. The electrolyte is the medium for lithium ions to migrate between the positive and negative electrodes, and its uniformity directly affects the consistency of the electrochemical reactions inside the battery and its overall performance. Insufficient electrolyte wetting in the top core area leads to decreased ionic conductivity and increased resistance in that area, causing problems such as localized overcharging and lithium dendrite precipitation, ultimately resulting in accelerated battery capacity decay and shortened cycle life.

[0003] Currently, most solutions to this problem focus on optimizing electrolyte formulations or improving injection processes, but the effects are limited. Summary of the Invention

[0004] This disclosure provides a capillary array structure, a lithium-ion battery, and a method for electrolyte conduction, to at least solve the above-mentioned technical problems existing in the prior art.

[0005] According to a first aspect of this disclosure, a capillary array structure is provided, the capillary array structure being a hollow column. The capillary array structure includes multiple capillary units, which are arranged in a ring around the axis of the column. Each capillary unit comprises at least three capillaries with different inner diameters, and the inner wall of each capillary is hydrophilically modified.

[0006] In one embodiment, in each of the capillary units, the at least three capillaries with different inner diameters are evenly spaced within the capillary unit.

[0007] In one embodiment, the spacing between the capillary units is equal to the spacing between the capillaries within each capillary unit.

[0008] In one embodiment, the plurality of capillary units are arranged in multiple layers along the radial direction of the column.

[0009] In one embodiment, at least one end of the column is fitted with an annular member, the inner diameter of which is adapted to the outer diameter of the column; The annular component has multiple through holes.

[0010] In one embodiment, the annular component and the column are integrally formed.

[0011] In one embodiment, within each capillary unit, the center-to-center distance between adjacent capillaries is 1.5 to 2 times its maximum inner diameter.

[0012] In one embodiment, the hydrophilic modification treatment includes plasma treatment and hydrophilic coating treatment.

[0013] According to a second aspect of this disclosure, a lithium-ion battery is provided, comprising a capillary array structure as described in any of the preceding embodiments, the capillary array structure being disposed at the center of its core along the axial direction of the lithium-ion battery.

[0014] According to a third aspect of this disclosure, a method for electrolyte conduction in a lithium-ion battery is provided, employing the capillary array structure described in any of the above embodiments for electrolyte conduction, the electrolyte conduction method comprising: The capillary array structure is positioned at the center of the core along the axial direction of the lithium-ion battery. An electrolyte is injected into the lithium-ion battery, allowing the electrolyte to diffuse and conduct upward along the capillary tubes under the capillary action of the capillary array structure.

[0015] This disclosure discloses a capillary array structure, a lithium-ion battery, and an electrolyte conduction method. Through the coordinated operation of at least three capillaries with different inner diameters within each capillary unit, it achieves both high-altitude electrolyte transport and efficient diffusion after transport, solving the problem of insufficient electrolyte wetting at the top of tall batteries. The annular distribution design around the column axis, combined with the coordinated transport of multiple inner diameter capillaries, enables synchronous diffusion of the electrolyte from the center of the core to the entire radial region, effectively eliminating wetting blind spots and ensuring balanced electrolyte supply to all areas of the battery core. Furthermore, the shape of the hollow cylinder can be flexibly adjusted according to the core size of different lithium-ion battery specifications, without requiring modification to existing battery production processes, and can be directly adapted to existing mass production processes, thus having a wide range of applications. Furthermore, the array is an integrated cylindrical structure with compact and robust capillary units. Under conditions such as long-term battery charge-discharge and high- and low-temperature cycling, it can maintain a stable structural shape and transmission performance, and is not prone to loosening or blockage. This capillary array structure applied in the middle of the core also provides a certain degree of support, preventing the collapse of the core layer in the middle of the core due to expansion during the charge-discharge cycle, thus ensuring structural stability and reliability. By optimizing the electrolyte wetting effect, problems such as increased resistance and lithium deposition caused by local electrolyte deficiency are reduced, effectively improving the cycle stability of the battery, extending battery life, and improving the charge-discharge consistency of the battery, significantly enhancing battery performance.

[0016] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0017] The above and other objects, features, and advantages of this disclosure will become readily apparent from the following detailed description of exemplary embodiments, taken in conjunction with the accompanying drawings. Several embodiments of this disclosure are illustrated in the drawings by way of example and not limitation, in which: In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0018] Figure 1 A schematic diagram of an overall structure of the capillary array structure according to an embodiment of the present disclosure is shown; Figure 2 A partially enlarged view of the overall structure of the capillary array structure according to an embodiment of the present disclosure is shown; Figure 3 This diagram illustrates another overall structural schematic of the capillary array structure according to an embodiment of the present disclosure; Figure 4 A partially enlarged view of another overall structure of the capillary array structure according to an embodiment of the present disclosure is shown; Figure 5A partial perspective view of a capillary array structure according to an embodiment of the present disclosure is shown; Figure 6 A partial perspective view of a lithium-ion battery according to an embodiment of the present disclosure is shown; Figure 7 A top view of the internal structure of a lithium-ion battery according to an embodiment of the present disclosure is shown.

[0019] The labels in the diagram are as follows: 1. Column; 2. Ring-shaped component; 3. Electrode; 11. Capillary; 21. Through hole; 100. Capillary array structure. Detailed Implementation

[0020] To make the objectives, features, and advantages of this disclosure more apparent and understandable, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0021] Reference Figure 1 , Figure 2 and Figure 5 As shown, this disclosure provides an exemplary embodiment of a capillary array structure 100. The capillary array structure 100 is a hollow cylinder 1, and includes a plurality of capillary units arranged in a ring around the axis of the cylinder 1. Each capillary unit includes at least three types of capillaries 11 with different inner diameters, and the inner wall of each capillary 11 is treated with a hydrophilic modification.

[0022] In this embodiment, the capillary array structure 100 is an overall hollow cylinder 1. On the one hand, the outer diameter and height of the hollow cylinder 1 can be flexibly adjusted according to the core size of the target lithium-ion battery, especially the large cylindrical lithium-ion battery, and can be directly embedded in the middle part of the core without making significant modifications to the existing battery structure and manufacturing process, thus exhibiting strong compatibility. On the other hand, the hollow structure not only ensures the structural stability of the array itself, but also reserves reasonable space for the middle area of ​​the core, avoiding affecting the compactness of the electrode winding, while providing a channel for the bidirectional flow of electrolyte inside and outside the array, facilitating uniform diffusion. Each capillary unit contains at least three capillaries 11 with different inner diameters. Compared to capillaries 11 with a single aperture, capillaries 11 with different inner diameters work together. For example, the capillary tube 11 with a relatively small inner diameter utilizes its stronger capillary force to handle the task of transporting the electrolyte from the bottom to the top of the battery at a higher height; the capillary tube 11 with a medium inner diameter acts as a transition, balancing flow resistance and transport speed; the capillary tube 11 with a relatively large inner diameter focuses on reducing flow resistance and expanding the diffusion area of ​​the electrolyte, ensuring that the electrolyte quickly covers the edge and top area of ​​the core, achieving full wetting. Through a combination of at least three different inner diameters, a balance between high-height transport and efficient diffusion is achieved for the first time. The inner wall of each capillary tube 11 is treated with hydrophilic modification to improve the wetting effect between the electrolyte and the inner wall of the capillary tube 11. The essence of capillary climb is the balance between capillary force and gravity, and the wetting effect between the electrolyte and the tube wall directly affects the magnitude of the capillary force. After hydrophilic modification, the electrolyte can better adhere to the tube wall and climb along the tube wall, effectively increasing the height and speed of capillary climb, while reducing residual loss of electrolyte on the tube wall and improving transport efficiency. This modification treatment provides key surface properties support for efficient electrolyte transport and is an important guarantee for achieving high-level, uniform wetting.

[0023] In summary, the capillary array structure 100 disclosed herein, through the coordinated operation of at least three capillary tubes 11 with different inner diameters within each capillary unit, achieves both high-altitude electrolyte transport and efficient diffusion after transport, solving the problem of insufficient electrolyte wetting at the top of high-height batteries. The annular distribution design around the axis of the cylinder 1, combined with the coordinated transport of the multi-diameter capillary tubes 11, enables synchronous diffusion of the electrolyte from the center of the core to the entire radial region, effectively eliminating wetting blind spots and ensuring balanced electrolyte supply to all areas of the battery core. Furthermore, the shape of the hollow cylinder 1 can be flexibly adjusted according to the core size of different lithium-ion battery specifications, without requiring modification to existing battery production processes, and can be directly adapted to existing mass production processes, thus having a wide range of applications. Furthermore, the array as a whole is an integrated columnar structure 1, with a compact and robust distribution of capillary units. Under conditions such as long-term battery charge-discharge and high-low temperature cycling, it can maintain a stable structural shape and transmission performance, and is not prone to loosening or blockage. This capillary array structure 100 applied in the middle of the core also has a certain supporting function, which can prevent the collapse of the core layer in the middle of the core due to expansion during the charge-discharge cycle of the cell, making the structure stable and reliable. By optimizing the electrolyte wetting effect, problems such as increased resistance and lithium deposition caused by local electrolyte deficiency are reduced, effectively improving the cycle stability of the battery, extending the battery life, and improving the charge-discharge consistency of the battery, thus significantly improving battery performance.

[0024] In one embodiment, in each capillary unit, at least three types of capillaries 11 with different inner diameters are evenly spaced within the capillary unit.

[0025] In this embodiment, at least three capillaries 11 with different inner diameters are evenly distributed within the capillary unit. This prevents excessive density of capillaries 11 with different inner diameters, avoids the superposition of flow resistance caused by an excessive number of local capillaries 11, and ensures that the transmission path of each inner diameter capillary 11 is independent and smooth, fully utilizing their respective climbing and diffusion functions. The evenly distributed capillaries 11 allow for a more balanced electrolyte supply in each area, and the electrolyte overflowing from a single capillary unit can form a uniform diffusion surface, further ensuring the wetting effect across the entire radial area of ​​the core. The design of the inner diameter of the capillary 11 is further explained below: The capillary lift height follows the capillary rise formula derived from the Yang-Laplace equation, namely:

[0026] Where h is the capillary lift height (m); γ is the surface tension of the electrolyte (N / m); θ is the wetting angle of the electrolyte on the inner wall of capillary 11 (°); and ρ is the density of the electrolyte (kg / m³). 3 g is the acceleration due to gravity (9.8 m / s²). 2 ); r is the inner diameter (m) of capillary tube 11.

[0027] As can be seen from the formula, the smaller the aperture, the higher the theoretical lifting height. However, in practice, a balance must be struck between "lifting height" and "liquid flow efficiency." If the aperture is too small, the viscous resistance will surge, preventing the liquid from climbing quickly or even causing blockage. Therefore, when designing the inner diameter of the capillary 11, it is necessary to first determine the key parameters of the electrolyte. This involves measuring the surface tension γ, density ρ, and wetting angle θ of the target electrolyte on the inner wall of the capillary 11. Then, based on the required maximum lifting height h, the inner diameter r of the capillary 11 is calculated using the formula, while reserving a resistance redundancy of 10% to 20%. Finally, the actual pore size is corrected. If the electrolyte viscosity is high, the pore size needs to be appropriately increased by 20% to 30% compared to the theoretical value to reduce viscous resistance. If the electrolyte contains minute impurities, the pore size needs to be 5 to 10 times larger than the impurity particle size to avoid clogging; a filter layer may be necessary. Alternatively, depending on the dynamic climbing requirements, such as the need for rapid and stable climbing, the pore size is usually selected as 50 to 200 μm. If the ultimate height is desired, the pore size can be reduced to 10 to 50 μm, but it must be ensured that the electrolyte is free of significant impurities. In this disclosure, the inner diameter ranges of the three capillary tubes 11 with different inner diameters are preferably 30 to 50 μm, 60 to 100 μm, and 100 to 150 μm. The inner walls of each capillary tube 11 are all subjected to hydrophilic modification treatment, with a wetting angle ≤35°. It is understood that in actual production applications, the size of the capillary array structure is not limited to the above ranges and can be adapted to the actual situation.

[0028] Furthermore, in one embodiment, the spacing between capillary units is equal to the spacing between capillaries 11 within each capillary unit.

[0029] In this embodiment, by matching the spacing, the distribution spacing of all capillaries 11 in the entire array is made completely consistent, avoiding defects such as local dense or sparse areas, and ensuring that every region in the radial direction of the core receives uniform electrolyte coverage. The uniform spacing design across the entire area ensures consistent flow resistance during electrolyte diffusion, preventing sudden changes in resistance due to excessively small local spacing, and avoiding excessively long electrolyte transport paths due to excessively large local spacing. This achieves uniform and efficient electrolyte diffusion throughout the core, optimizing overall flow resistance. The unified spacing standard reduces the design and manufacturing difficulty of the array structure, facilitating precision control during mass production.

[0030] In one embodiment, multiple capillary units are arranged in multiple layers along the radial direction of the column 1.

[0031] In this embodiment, the multi-layer design creates multiple ring-shaped distributions of capillary units from the inside out in the radial direction of the core. Each layer corresponds to a radial depth region of the core. After the electrolyte overflows from each layer of capillary units, it can simultaneously cover regions of different radial depths of the core, eliminating the problem of insufficient wetting at the edges caused by an excessively large core diameter. The multi-layer ring distribution, in conjunction with the ring distribution of each layer, constructs a three-dimensional transport network of axial climbing and radial multi-layer diffusion. After the electrolyte climbs from the bottom through capillary 11, it diffuses synchronously throughout the entire core via the multi-layer capillary units, significantly improving wetting efficiency and uniformity.

[0032] Reference Figure 3 and Figure 4 As shown, in one embodiment, at least one end of the column 1 is fitted with an annular member 2, the inner diameter of the annular member 2 is adapted to the outer diameter of the column 1, and the annular member 2 is provided with a plurality of through holes 21.

[0033] In this embodiment, the inner diameter of the annular component 2 is closely fitted to the outer diameter of the column 1, forming a positioning reference after being fitted. During assembly, the annular component 2 can precisely match the preset assembly position of the battery core, limiting the offset and tilt of the column 1 within the core. This ensures that the bottom of all capillary units is flush and precisely aligned with the electrolyte storage area at the bottom of the battery, preventing some capillary tubes 11 from failing to contact the electrolyte or having insufficient contact due to assembly deviations, thus ensuring the stability of the overall transmission efficiency of the array. At the same time, the annular component 2 can enhance the structural strength of the end of the column 1, preventing the capillary units from deforming or loosening during assembly, and improving the overall structural stability of the array. Multiple through holes 21 on the annular component 2 are evenly distributed. After the electrolyte climbs through the capillary tube 11 to the top of the column 1, it is diverted and guided through the through holes 21 of the top annular component 2, breaking the local confinement at the outlet of the capillary tube 11 and allowing the electrolyte to diffuse evenly from the through holes 21 to the entire area of ​​the top of the battery core. The diameter of the through holes 21 is slightly larger than the maximum inner diameter of the capillary tube 11, reducing the electrolyte diffusion resistance and preventing the electrolyte from accumulating at the outlet of the top capillary tube 11. This ensures that the top edge, corners and other areas of the core can obtain sufficient electrolyte, completely solving the core problem of insufficient top wetting.

[0034] Specifically, in one embodiment, the annular component 2 and the column 1 are integrally formed.

[0035] In this embodiment, the annular component 2 and the column 1 are integrally formed, eliminating connection gaps and the risk of loosening. The overall array structure has high strength and precise shape and position, can withstand the harsh working conditions of long-term battery cycling, and has stable and reliable performance over long-term use. Its service life is highly compatible with the battery body. The absence of additional assembly of the annular component 2 reduces assembly errors during mass production, improving production efficiency and product consistency. The positioning reference of the annular component 2 makes the array easy to insert into the core, ensuring accurate positioning and avoiding a decrease in transmission efficiency due to assembly deviations. The matrix material of the capillary array structure 100 is preferably a polymer with good chemical stability and compatibility with the electrolyte, such as modified polypropylene, polyphenylene sulfide, polytetrafluoroethylene, polyimide, polyphenylene ether, polyetheretherketone, etc. The porosity of the capillary 11 is controlled at 50%~70%.

[0036] In one embodiment, within each capillary unit, the center-to-center distance between adjacent capillaries 11 is 1.5 to 2 times their maximum inner diameter.

[0037] In this embodiment, the capillary tube 11 with the largest inner diameter has the lowest fluid resistance but the widest diffusion range. Using this as a benchmark for spacing design avoids both excessively small spacing leading to mutual interference and resistance superposition between adjacent capillary tubes 11, and excessively large spacing preventing insufficient diffusion density and localized wetting blind zones in the core. In the multi-inner-diameter capillary tube 11 combination, the size of the large inner-diameter capillary tube 11 determines the minimum reasonable spacing within the unit. Small inner-diameter capillary tubes 11 can fully utilize their high capillary force advantage at this spacing without requiring separate spacing adjustments. This simplifies the structural design while ensuring seamless functional coordination of capillary tubes 11 with different inner diameters.

[0038] In one embodiment, the hydrophilic modification treatment includes plasma treatment and hydrophilic coating treatment.

[0039] In this embodiment, plasma treatment employs plasma etching technology to treat the inner wall of capillary 11. Through the physical bombardment and chemical activation of plasma, oil and impurities on the inner wall of capillary 11 are removed, creating a micro-rough structure on the inner wall surface and increasing the specific surface area. Simultaneously, active groups such as hydroxyl and carboxyl groups are introduced onto the surface, enhancing the chemical bonding ability between the subsequent hydrophilic coating and the inner wall, thus solving the problem of easy peeling off of a single coating. The hydrophilic coating process involves applying a hydrophilic coating to the inner wall of the plasma-treated capillary 11. The coating material is preferably a polyethylene glycol derivative or a silane coupling agent, which has good compatibility with the electrolyte and strong chemical stability. The coating process can employ immersion or spraying methods. The hydrophilic coating itself has extremely strong hydrophilic properties, significantly reducing the wetting angle between the electrolyte and the tube wall (≤35°), and significantly improving capillary climbing force. Plasma treatment provides a strong adhesion foundation for hydrophilic coatings, while the hydrophilic coatings provide hydrophilic properties. The combination of the two not only solves the problems of insufficient hydrophilicity and poor durability of plasma treatment alone, but also overcomes the defects of weak adhesion of single coatings, achieving a dual breakthrough in hydrophilic effect and durability.

[0040] Reference Figure 6 and Figure 7 As shown, this disclosure also provides a lithium-ion battery, including a capillary array structure 100 as described in any of the above embodiments, wherein the capillary array structure 100 is disposed at the center of the core of the lithium-ion battery along the axial direction of the battery.

[0041] In this embodiment, the capillary array structure 100 is positioned along the battery axial direction at the center of the core, specifically in the hollow central region formed by the core winding. This position represents the optimal path for electrolyte transport, ensuring that the winding of the positive and negative electrode plates 3 and the separator is compact, while allowing the electrolyte to travel axially from the bottom to the top, shortening the transport distance and preventing path deviation. The height of the capillary array structure 100 is consistent with the height of the core, ensuring full height coverage from the bottom to the top of the core. The outer diameter closely matches the inner diameter of the hollow central region of the core, ensuring secure assembly while preventing excessive gaps that could lead to electrolyte retention or structural loosening.

[0042] Because the lithium-ion battery disclosed herein includes a capillary array structure 100, the coordinated operation of at least three capillaries 11 with different inner diameters within each capillary unit achieves both high-altitude electrolyte transport and efficient diffusion after transport, solving the problem of insufficient electrolyte wetting at the top of high-altitude batteries. The annular distribution design around the axis of the cylinder 1, combined with the coordinated transport of the multi-diameter capillaries 11, enables synchronous diffusion of the electrolyte from the center of the core to the entire radial region, effectively eliminating wetting blind spots and ensuring balanced electrolyte supply to all areas of the battery core. Furthermore, the shape of the hollow cylinder 1 can be flexibly adjusted according to the core size of different lithium-ion battery specifications, without requiring modification of existing battery production processes, and can be directly adapted to existing mass production processes, thus having a wide range of applications. Furthermore, the array as a whole is an integrated columnar structure 1, with a compact and robust distribution of capillary units. Under conditions such as long-term battery charge-discharge and high-low temperature cycling, it can maintain a stable structural shape and transmission performance, and is not prone to loosening or blockage. This capillary array structure 100 applied in the middle of the core also has a certain supporting function, which can prevent the collapse of the core layer in the middle of the core due to expansion during the charge-discharge cycle of the cell, making the structure stable and reliable. By optimizing the electrolyte wetting effect, problems such as increased resistance and lithium deposition caused by local electrolyte deficiency are reduced, effectively improving the cycle stability of the battery, extending the battery life, and improving the charge-discharge consistency of the battery, thus significantly improving battery performance.

[0043] This disclosure also provides a method for electrolyte conduction in a lithium-ion battery, which uses the capillary array structure 100 in any of the foregoing embodiments for electrolyte conduction. The electrolyte conduction method includes: Step 1: Position the capillary array structure 100 along the axial direction of the lithium-ion battery at the center of its core. Step 2: Inject electrolyte into the lithium-ion battery, so that the electrolyte diffuses and conducts upward from the bottom along the capillary 11 under the capillary action of the capillary array structure 100.

[0044] In this embodiment, in step 1, the capillary array structure 100 is fixedly positioned at the center of the core along the axial direction of the lithium-ion battery. The height of the capillary array structure 100 is adapted to the height of the core, the bottom is aligned with the electrolyte storage area inside the battery casing, and the top extends to the top area of ​​the core. In step 2, electrolyte is injected into the lithium-ion battery casing, ensuring that the electrolyte covers the bottom of the capillary array structure 100 and the electrolyte surface is flush with the bottom of the core. Under the capillary action of the capillary array structure 100, the electrolyte diffuses and conducts upward along the inner wall of the capillary 11, sequentially completing a significant height increase and radial diffusion, ultimately achieving uniform wetting of the entire core. Specifically, after the electrolyte is injected, it comes into contact with the bottom of the capillary array structure 100. Under the combined action of adsorption by the hydrophilic modified inner wall and capillary force, it quickly penetrates into the interior of the capillary 11. The small-diameter capillary 11 provides strong capillary force, driving the electrolyte to climb axially from bottom to top. With the help of the array height adaptation design, it reaches the top of the core. If the array includes a top annular component 2, the electrolyte is diverted twice through the through hole 21, further improving the diffusion uniformity. The diffused electrolyte gradually penetrates to the positive and negative electrode plates 3 and the diaphragm, completing the uniform wetting of the core in all heights and radial directions.

[0045] In summary, the electrolyte conduction method for lithium-ion batteries disclosed herein significantly improves the bottom-to-top electrolyte conduction speed by leveraging the capillary action and central axial positioning of the capillary array structure 100. Relying on the structural advantages of the capillary array structure 100 itself, the capillary conduction effect is long-lasting. The electrolyte conduction method for lithium-ion batteries is simple in procedure, and the array assembly can be integrated into existing large cylindrical battery production processes without modifying the production line. The injection and settling processes are compatible with traditional processes, requiring only optimization of the conduction logic, facilitating industrial mass production. It is adaptable to lithium-ion batteries of different heights and diameters, and compatible with various electrolyte systems such as carbonates and ionic liquids, making it suitable for a wide range of applications.

[0046] Taking a lithium-ion cylindrical battery as an example, the following describes the preparation process of a lithium-ion cylindrical battery: Positive electrode preparation: LiNi with a mass percentage of 96.5% 0.95 Co 0.05 Mn 0.03 O2, 2% polyvinylidene fluoride binder, and 1.5% conductive carbon black are added together to N-methylpyrrolidone solvent and stirred thoroughly to form a uniform positive electrode slurry with a solid content of 68.9 wt%. The slurry is then uniformly coated on both sides of an aluminum foil, dried, and rolled to finally produce the desired positive electrode sheet.

[0047] Negative electrode preparation: Artificial graphite was selected as the negative electrode active material, and mixed with styrene-butadiene rubber, carboxymethyl cellulose binder, and vapor-grown carbon fiber conductive agent at a mass percentage of 95:1.5:1.5:2. The mixture was then added to deionized water and stirred to disperse, resulting in a negative electrode slurry with a solid content of 39.5 wt%. This slurry was coated on both sides of a copper foil, and after drying and rolling, the negative electrode sheet was obtained.

[0048] Electrolyte preparation: Diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, and propylene carbonate were mixed uniformly in a mass ratio of 45:20:25:10 to form the electrolyte solvent system. LiPF6, LiFSI, and LiPO2F2 were selected as electrolyte salts. All three were deeply dried before being added to the solvent. They were then added to the mixed solvent in proportions of 12.0 wt%, 2.5 wt%, and 2.5 wt%, respectively, and stirred continuously until completely dissolved, finally yielding an electrolyte with both water and oxygen contents below 0.01 ppm.

[0049] The diaphragm is selected as follows: a composite diaphragm with polyethylene as the base membrane and a base membrane thickness of 9μm is used; the diaphragm surface is coated with a ceramic mixed coating composed of polyvinylidene fluoride and boehmite with a coating thickness of 3μm. The air permeability index of this composite diaphragm is 140s / 100mL.

[0050] Battery assembly and forming: First, the prepared positive and negative electrode sheets are sequentially rolled, baked, slit, and laser-cut with tabs. Then, an automatic winding machine sequentially winds the positive electrode sheet, separator, and negative electrode sheet to form a battery core, and folds the positive and negative electrode tabs of the core. After welding the positive and negative busbars of the core, the core is inserted into a cylindrical steel shell, further welding the negative busbar to the steel shell and the positive busbar to the positive terminal block connector. Finally, the positive terminal block is sealed and welded to the steel shell. Subsequent processes include cell baking, electrolyte injection, negative pressure formation, and sealing welding, ultimately producing a cylindrical lithium-ion battery with a diameter of 46mm, a height of 120mm, and a rated capacity of 35Ah.

[0051] Finally, the electrical performance of the lithium-ion cylindrical battery was tested: the lithium-ion battery including the capillary array structure 100 in this disclosure and the comparative battery without the capillary array structure 100 were subjected to charge-discharge tests. The battery was charged at a constant current of 1C to 4.20V, charged at a constant voltage to 0.05C cutoff, and discharged at a constant current of 1C to 0.05V until 500 cycles were completed and the capacity retention rate was recorded to obtain the performance comparison results.

[0052] Table 2 Performance Comparison Table

[0053] It is evident that the lithium-ion cylindrical battery using the capillary array structure 100 has a significantly higher capacity retention rate after 500 cycles compared to the cylindrical lithium-ion battery without the capillary array structure 100. At the same time, its DCIR (direct current internal resistance) and ACIR (alternating current internal resistance) are lower than those of the traditional lithium-ion cylindrical battery without the capillary array structure 100. This is mainly due to the sufficient wetting of the top of the cell.

[0054] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this disclosure can be achieved, and this is not limited herein.

[0055] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0056] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure 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 disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A capillary array structure, characterized in that, The capillary array structure (100) is a hollow column (1). The capillary array structure (100) includes multiple capillary units, which are arranged in a ring around the axis of the column (1). Each of the capillary units includes at least three capillaries (11) with different inner diameters, and the inner wall of each capillary (11) is treated with hydrophilic modification.

2. The capillary array structure according to claim 1, characterized in that, In each capillary unit, the at least three capillaries with different inner diameters are evenly spaced within the capillary unit.

3. The capillary array structure according to claim 2, characterized in that, The spacing between the capillary units is equal to the spacing between the capillaries (11) within each capillary unit.

4. The capillary array structure according to any one of claims 1 to 3, characterized in that, The multiple capillary units are arranged in multiple layers along the radial direction of the column (1).

5. The capillary array structure according to claim 1, characterized in that, At least one end of the column (1) is fitted with an annular piece (2), the inner diameter of which is adapted to the outer diameter of the column (1); The annular component (2) has multiple through holes (21).

6. The capillary array structure according to claim 5, characterized in that, The annular component (2) and the column (1) are integrally formed.

7. The capillary array structure according to any one of claims 1 to 3, characterized in that, Within each capillary unit, the center-to-center distance between adjacent capillaries (11) is 1.5 to 2 times their maximum inner diameter.

8. The capillary array structure according to claim 1, characterized in that, The hydrophilic modification treatment includes plasma treatment and hydrophilic coating treatment.

9. A lithium-ion battery, characterized in that, Includes a capillary array structure (100) as described in any one of claims 1-8, wherein the capillary array structure (100) is disposed at the center of the core along the axial direction of the lithium-ion battery.

10. A method for electrolyte conduction in a lithium-ion battery, characterized in that, Electrolyte conduction is performed using the capillary array structure (100) according to any one of claims 1-8, wherein the electrolyte conduction method comprises: The capillary array structure (100) is positioned at the center of the core along the axial direction of the lithium-ion battery. Electrolyte is injected into the lithium-ion battery, so that the electrolyte diffuses and conducts upward from the bottom along the capillary tubes (11) under the capillary action of the capillary array structure (100).

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