Lithium ion battery pole piece structure with low internal resistance and manufacturing method thereof

Abstract

The invention discloses a low-internal-resistance lithium ion battery pole piece structure and a manufacturing method thereof, the pole piece structure comprises a current collector, and a first coating and a second coating which are laminated, the first coating is located between the current collector and the second coating, contains linear and dotted composite conductive agents and forms a three-dimensional conductive network, and the content of the conductive agent in the second coating is lower; the type of a conductive material, the thickness of a coating, the proportion of a conductive agent and the type of a current collector are limited. The manufacturing method comprises the steps of slurry preparation, layered coating, segmented drying, rolling compaction and the like, and dispersion, drying and rolling parameters are accurately controlled. The invention can obviously reduce the internal resistance of the pole piece, balance the conductivity and energy density, improve the structural stability of the pole piece, prolong the cycle life of the battery and control the production cost, is adaptive to the existing production line, has higher industrial value, and can meet the application requirement of the high-performance lithium ion battery.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, specifically to a low internal resistance lithium-ion battery electrode structure and its manufacturing method. Background Technology

[0002] Lithium-ion batteries are widely used in various electronic devices, energy storage, and power battery fields due to their high energy density and long cycle life. As the core component for energy storage and charge conduction, the electrode's structural design directly determines key performance characteristics such as internal resistance and energy density. Currently, most lithium-ion battery electrodes employ a single active material coating structure, with the conductive agent often being a single-point conductive material. This easily leads to problems such as discontinuous conductive networks and "conductive dead zones," resulting in high internal resistance and affecting battery charge / discharge efficiency and high-rate performance. Increasing the amount of conductive agent to reduce internal resistance occupies space filled with active material, causing a decrease in energy density. Furthermore, a single coating cannot simultaneously meet both conductivity and energy storage requirements, and the relatively high contact resistance between the current collector and the coating further restricts the improvement of electrode performance. Summary of the Invention

[0003] To overcome the shortcomings of existing technical solutions, this invention provides a low internal resistance lithium-ion battery electrode structure and its manufacturing method, which can effectively solve the problems raised in the background art.

[0004] The technical solution adopted by this invention to solve its technical problem is:

[0005] A low internal resistance lithium-ion battery electrode structure includes a current collector and an active material layer disposed on at least one surface of the current collector, wherein the active material layer includes a first coating layer and a second coating layer stacked together.

[0006] The first coating is located between the current collector and the second coating. The first coating includes first active material particles and a first conductive agent. The first conductive agent includes linear conductive material and dot-shaped conductive material. The linear conductive materials overlap to form a three-dimensional conductive network skeleton. The dot-shaped conductive material is distributed between and on the surface of the first active material particles and connects the first active material particles with the three-dimensional conductive network skeleton.

[0007] The second coating comprises second active material particles and a second conductive agent, wherein the content of the second conductive agent in the second coating is lower than the total content of the first conductive agent in the first coating.

[0008] As a further description of the above technical solution, the linear conductive material is one or more of carbon nanotubes, carbon nanofibers, or vapor-grown carbon fibers.

[0009] The dotted conductive material is one or more of conductive carbon black, acetylene black, or Ketjen black.

[0010] As a further description of the above technical solution, the thickness of the first coating is 1 / 5 to 1 / 3 of the total thickness of the active material layer.

[0011] As a further description of the above technical solution, in the first coating, the mass of the linear conductive material accounts for 0.5% to 3% of the total solid content of the first coating, and the mass of the dot-shaped conductive material accounts for 0.5% to 2% of the total solid content of the first coating.

[0012] As a further description of the above technical solution, the second coating does not contain linear conductive materials, the second conductive agent is only a dot-shaped conductive material, and its mass accounts for 0.5% to 1.5% of the total solid content of the second coating.

[0013] As a further description of the above technical solution, the current collector is a carbon-coated aluminum foil or a plain aluminum foil, and the conductive coating of the carbon-coated aluminum foil is in contact with the first coating.

[0014] A method for manufacturing a low internal resistance lithium-ion battery electrode structure includes the following steps:

[0015] Step S1: Prepare the first slurry by mixing the first active substance, the first conductive agent containing linear conductive material and dot-shaped conductive material, the first binder and the first solvent, and by using the first dispersion process to disperse the linear conductive material and allow it to overlap to form a pre-three-dimensional network;

[0016] Step S2: Prepare the second slurry by mixing the second active material, the second conductive agent, the second binder, and the second solvent, and then uniformly dispersing the components through the second dispersion process;

[0017] Step S3: The first slurry prepared in step S1 is coated onto the surface of the current collector, and after a first drying treatment, a first coating preform is formed;

[0018] Step S4: Coat the surface of the first coating blank with the second slurry prepared in step S2, and perform a second drying treatment to allow the first coating blank and the second coating to be cured and formed simultaneously to form an active material layer.

[0019] As a further description of the above technical solution, the first dispersion process in step S1 adopts a combination of high-speed shear dispersion and ultrasonic-assisted dispersion, the dispersion temperature is controlled between 25°C and 45°C, and the viscosity of the dispersed slurry is between 3000 mPa·s and 8000 mPa·s.

[0020] As a further description of the above technical solution, the first drying process and the second drying process in step S4 adopt a segmented drying method, including a low temperature section and a high temperature section. The temperature of the low temperature section is 50°C to 70°C, and the temperature of the high temperature section is 80°C to 120°C.

[0021] As a further description of the above technical solution, after step S4, step S5 is also included: rolling and compacting the dried electrode sheet, wherein the rolling and compaction temperature is 60°C to 90°C, so that the porosity of the first coating is controlled at 25% to 35% and the porosity of the second coating is controlled at 30% to 40%.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] The low internal resistance lithium-ion battery electrode structure and its manufacturing method of the present invention have at least one of the following beneficial effects during use:

[0024] This low-internal-resistance lithium-ion battery electrode structure and manufacturing method significantly reduces electrode internal resistance and improves battery charge / discharge efficiency and high-rate performance through layered coating design and precise process control. The composite conductive network of the first coating eliminates conductive dead zones, and the rational selection of the current collector further reduces contact resistance, achieving low-resistance conduction of both electrons and lithium ions. The second coating optimizes the conductive agent configuration, maximizing energy density while controlling costs. Precisely defining the thickness, conductive agent ratio, and porosity of each coating balances conductivity and structural stability, preventing active material shedding and coating defects. Adapted dispersion, drying, and rolling processes ensure coating quality and conductive network stability, improving electrode mechanical strength and cycle life. The overall solution balances performance and cost, is compatible with existing production lines, has strong industrial value, and can meet the application requirements of high-performance lithium-ion batteries. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of a low internal resistance lithium-ion battery electrode structure according to the present invention.

[0026] Figure 2 This is a partial structural schematic diagram of a low internal resistance lithium-ion battery electrode structure according to the present invention.

[0027] Figure 3 This is a schematic diagram of the manufacturing process of a low internal resistance lithium-ion battery electrode structure according to the present invention.

[0028] Numbering on the map:

[0029] 1. Current collector; 2. First coating; 3. Second coating; 4. First conductive agent; 5. Dot-shaped conductive material; 6. First active material particles; 7. Linear conductive material; 8. Second conductive agent; 9. Second active material particles. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0031] like Figure 1-3 As shown, the present invention provides a low internal resistance lithium-ion battery electrode structure, including a current collector 1 and an active material layer disposed on at least one surface of the current collector 1, wherein the active material layer includes a first coating layer 2 and a second coating layer 3 stacked together.

[0032] The first coating 2 is located between the current collector 1 and the second coating 3. The first coating 2 includes first active material particles 6 and first conductive agent 4. The first conductive agent 4 includes linear conductive material 7 and dot-shaped conductive material 5. The linear conductive material 7 overlaps with each other to form a three-dimensional conductive network skeleton. The dot-shaped conductive material 5 is distributed between and on the surface of the first active material particles 6 and connects the first active material particles 6 with the three-dimensional conductive network skeleton.

[0033] The first coating 2 is located between the current collector 1 and the second coating 3, serving as a "conductive transition layer." Its core function is to build an efficient conductive bridge between the current collector 1 and the active material. The first coating 2 simultaneously contains linear conductive materials 7 (carbon nanotubes, carbon nanofibers, etc.) and dot-like conductive materials 5 (conductive carbon black, Ketjen black, etc.). The linear conductive materials 7 form a three-dimensional conductive network framework by overlapping each other, which is equivalent to a "main circuit" and can quickly conduct electrons. The dot-like conductive materials 5 are distributed between and on the surface of the first active material particles 6, which is equivalent to a "branch circuit." On the one hand, they fill the gaps between the active material particles, and on the other hand, they connect the first active material particles 6 to the three-dimensional conductive network framework, ensuring that each active material particle can be connected to the conductive network and avoiding "conductive dead zones." In addition, if the current collector 1 is made of carbon-coated aluminum foil, the conductive coating on its surface is in direct contact with the first coating 2, which can further reduce the contact resistance between the current collector 1 and the first coating 2 and improve the electron conduction efficiency.

[0034] The three-dimensional conductive network framework constructed by the linear conductive material 7 in the first coating 2 forms a continuous and efficient electron conduction pathway. Compared with the "discrete conductivity" of traditional single-point conductive agents, it can significantly reduce the contact resistance during electron conduction. The supplementary role of the point-like conductive material 5 further eliminates the conductive gaps between active material particles, ensuring no dead zones in electron conduction and fundamentally reducing the electron conduction resistance inside the electrode. This reduces the contact resistance between the current collector 1 and the active material layer, reducing the resistance to electron conduction from the conductive network to the current collector 1. The precise control of the porosity of the layered coating reduces the path resistance during lithium-ion diffusion, achieving low resistance in both electron conduction and lithium-ion diffusion.

[0035] The second coating 3 contains second active material particles 9 and a second conductive agent 8, and the content of the second conductive agent 8 in the second coating 3 is lower than the total content of the first conductive agent 4 in the first coating 2.

[0036] The second coating 3 is located outside the first coating 2 and serves as the "main energy storage layer." Its core function is to carry a large amount of active material and ensure the energy density of the battery. The second coating 3 contains only a small amount of dot-shaped conductive material 5 (or the total content of conductive agent is lower than that of the first coating 2), and no linear conductive material 7 is added. This is because the three-dimensional conductive network of the first coating 2 can already achieve efficient electron conduction, and the second coating 3 does not need to repeatedly construct a complex conductive network. Reducing the amount of conductive agent can increase the amount of active material filling and improve the energy density. At the same time, the dot-shaped conductive material 5 can meet the electron conduction requirements between the active material particles inside the second coating 3, avoiding increased polarization due to insufficient conductivity.

[0037] The thickness, conductive agent content, and porosity of the two coating layers are precisely matched (e.g., the thickness of the first coating 2 is 1 / 5 to 1 / 3 of the total thickness of the active material layer, the porosity of the first coating 2 is 25%-35%, and that of the second coating 3 is 30%-40%). This ensures both the dominant conductive role of the first coating 2 and the energy storage capacity of the second coating 3. The electron conduction path is: active material particles → dot-shaped conductive material 5 → three-dimensional conductive network framework → current collector 1, which is short and has low resistance. The lithium-ion diffusion path is: electrolyte → pores of the second coating 3 → pores of the first coating 2 → surface of the current collector 1 (or inside the active material particles). The reasonable porosity design can reduce the lithium-ion diffusion resistance and avoid the active material from falling off due to excessively large pores, achieving synergistic optimization of electron conduction and lithium-ion diffusion, and ultimately reducing the overall internal resistance of the electrode.

[0038] Furthermore, the linear conductive material 7 is one or more of carbon nanotubes, carbon nanofibers, or vapor-grown carbon fibers.

[0039] The dotted conductive material 5 is one or more of conductive carbon black, acetylene black, or Ketjen black.

[0040] The linear conductive material 7 uses materials with higher electronic conductivity and better mechanical strength, which can effectively reduce contact resistance during electronic conduction. At the same time, it can provide stable support for the active material particles, improve the stability of the coating structure, and prevent the conductive network from breaking during cycling. The dot-shaped conductive materials 5 are all mature conductive agents in the field of lithium-ion batteries. They have the characteristics of small particle size, large specific surface area, and good dispersibility. They can uniformly fill between and on the surface of the first active material particles 6, and accurately connect the active material particles to the three-dimensional conductive network skeleton.

[0041] Furthermore, the thickness of the first coating 2 is 1 / 5 to 1 / 3 of the total thickness of the active material layer.

[0042] Its thickness range can fully exert the dominant role of conductivity. Its internal three-dimensional conductive network can fully cover the entire active material layer, realizing the efficient conduction of electrons from the second coating 3 to the current collector 1. This avoids the incomplete conductive network and increased contact resistance caused by the first coating 2 being too thin, or the excessive thickness occupying too much active material storage space and reducing the energy density of the electrode.

[0043] A thickness ratio of 1 / 5 to 1 / 3 allows the first coating 2 and the second coating 3 to form a reasonable thickness ratio. The second coating 3 (the main energy storage layer) can occupy the main space of the active material layer, maximize the filling of active material, and ensure the energy density of the electrode. At the same time, the thickness of the first coating 2 is sufficient to support the stable formation of the three-dimensional conductive network, avoiding insufficient mechanical strength and peeling off during cycling due to the coating being too thin.

[0044] Furthermore, in the first coating 2, the mass of the linear conductive material 7 accounts for 0.5% to 3% of the total solid content of the first coating 2, and the mass of the dot-shaped conductive material 5 accounts for 0.5% to 2% of the total solid content of the first coating 2.

[0045] A mass ratio of 70.5%-3% for linear conductive materials ensures that they can be fully dispersed and interconnected to form a stable three-dimensional conductive network framework. If the proportion is too low, a continuous conductive path cannot be formed, resulting in increased resistance to electron conduction. If the proportion is too high, it will increase the cost of raw materials (linear conductive materials such as carbon nanotubes are expensive), and may also lead to difficulties in slurry dispersion, abnormal coating porosity, and hinder lithium-ion diffusion.

[0046] A dot-shaped conductive material with a mass ratio of 50.5%-2% can precisely fill the gaps between active material particles, effectively connect the active material to the three-dimensional conductive network, and eliminate conductive dead zones. If the proportion is too low, the active material and the conductive network cannot be fully connected. If the proportion is too high, it will occupy the space filled by the active material, reduce the energy density, and may also lead to a decrease in the mechanical strength of the coating.

[0047] Furthermore, the second coating 3 does not contain linear conductive material 7, and the second conductive agent 8 is only a dot-shaped conductive material 5, and its mass accounts for 0.5% to 1.5% of the total solid content of the second coating 3.

[0048] The second coating 3 does not contain linear conductive material 7, which avoids the linear conductive material 7 occupying the space for the active material filling in the second coating 3, maximizes the content of active material in the second coating 3, significantly improves the energy density of the electrode, and thus improves the battery's range; at the same time, it reduces the overall amount of linear conductive material 7, and significantly reduces the cost of raw materials.

[0049] A dot-shaped conductive agent with a mass ratio of 0.5%-1.5% can meet the electron conduction requirements between active material particles inside the second coating 3, ensuring that electrons can be smoothly transferred to the three-dimensional conductive network of the first coating 2, avoiding increased polarization and internal resistance due to insufficient conductive agent; at the same time, this proportion is lower than that of the first coating 2, which can further reduce the amount of conductive agent used, balancing conductivity and energy density.

[0050] Furthermore, the current collector 1 is a carbon-coated aluminum foil or a plain aluminum foil, and the conductive coating of the carbon-coated aluminum foil is in contact with the first coating 2.

[0051] The current collector 1 is made of either carbon-coated aluminum foil or plain aluminum foil. Both materials possess excellent conductivity, mechanical strength, and chemical stability, making them suitable for the electrochemical environment of lithium-ion batteries. They can effectively conduct electrons while supporting the entire active material layer, preventing electrode deformation and damage. The conductive coating of the carbon-coated aluminum foil is in direct contact with the first coating 2, significantly reducing the contact resistance between the current collector 1 and the first coating 2. The conductive coating on the surface of the carbon-coated aluminum foil can directly overlap with the three-dimensional conductive network of the first coating 2, reducing the resistance to electron conduction from the conductive network to the current collector 1, further reducing the overall internal resistance of the electrode, and improving battery charge and discharge efficiency, especially suitable for high-rate charge and discharge scenarios.

[0052] A method for manufacturing a low internal resistance lithium-ion battery electrode structure includes the following steps:

[0053] Step S1: Prepare the first slurry by mixing the first active substance, the first conductive agent 4 containing linear conductive material 7 and dot-shaped conductive material 5, the first binder and the first solvent, and by using the first dispersion process to disperse the linear conductive material 7 and allow them to overlap to form a pre-three-dimensional network.

[0054] A combination of high-speed shear dispersion and ultrasonic-assisted dispersion is employed. On one hand, high-speed shearing breaks down the agglomerates of the linear conductive material 7, ensuring its uniform dispersion in the slurry. On the other hand, ultrasonic-assisted dispersion promotes the bonding between the linear conductive materials 7, forming a pre-three-dimensional conductive network in advance, laying the foundation for the conductivity of the subsequent coating. The dispersion temperature is controlled between 25°C and 45°C, and the viscosity of the dispersed slurry is between 3000 mPa·s and 8000 mPa·s. This avoids excessively high temperatures that could lead to binder failure or abnormal viscosity, ensuring the coating performance and dispersion uniformity of the slurry.

[0055] Step S2: Prepare the second slurry by mixing the second active material, the second conductive agent 8, the second binder, and the second solvent, and then uniformly dispersing the components through the second dispersion process.

[0056] The second active material, dotted conductive agent, binder and solvent are uniformly mixed by conventional dispersion process. There is no need to build a complex conductive network. Therefore, the dispersion process is relatively simple. The key is to ensure uniform dispersion of active material and avoid uneven conductivity caused by local agglomeration. At the same time, the viscosity of the slurry is controlled to adapt to the subsequent coating requirements.

[0057] Step S3: The first slurry prepared in step S1 is coated on the surface of the current collector 1, and after a first drying treatment, a first coating 2 blank is formed;

[0058] Step S4: Coat the surface of the first coating 2 blank with the second slurry prepared in step S2, and perform a second drying treatment so that the first coating 2 blank and the second coating 3 are cured and formed simultaneously to form an active material layer.

[0059] First, a first slurry is applied and preliminarily dried to form a first coating 2 preform (not fully cured). Then, a second slurry is applied to its surface, followed by segmented drying (low-temperature segment 50°C-70°C, high-temperature segment 80°C-120°C). The low-temperature segment allows the solvent in the slurry to evaporate slowly, avoiding rapid solvent evaporation that could cause pinholes or cracking in the coating. The high-temperature segment allows the binder to fully cure, enabling the first coating 2 and the second coating 3 to cure and form simultaneously, enhancing the bonding force between the two coatings, preventing delamination, and ensuring the stable formation of the three-dimensional conductive network of the first coating 2.

[0060] Roller compaction at temperatures between 60°C and 90°C can, on the one hand, increase the areal density of the electrode, increase the amount of active material filling, and improve the energy density; on the other hand, it can precisely control the porosity of the first and second coatings 3 (225%-35% for the first coating and 330%-40% for the second coating). Excessive porosity will lead to poor contact of the active material and increased internal resistance, while insufficient porosity will hinder lithium-ion diffusion. A reasonable porosity design can achieve a balance between electron conduction and lithium-ion diffusion, further reduce the internal resistance of the electrode, and at the same time improve the mechanical strength of the electrode, preventing the active material from falling off during cycling.

[0061] Furthermore, the first dispersion process in step S1 adopts a combination of high-speed shear dispersion and ultrasonic-assisted dispersion, with the dispersion temperature controlled between 25°C and 45°C, and the viscosity of the dispersed slurry between 3000 mPa·s and 8000 mPa·s.

[0062] High-speed shearing can quickly break up the agglomerates of linear conductive material 7 and initially disperse them into the slurry system; ultrasonic-assisted dispersion can further refine the dispersed particles, promote uniform overlap between linear conductive materials 7, and form a stable pre-three-dimensional conductive network in advance, avoiding discontinuity of the conductive network and increased internal resistance caused by the agglomeration of linear conductive material 7. At the same time, it ensures that the first active material, conductive agent and binder are uniformly distributed in the slurry, and improves the consistency of the coating.

[0063] The dispersion temperature is controlled between 25°C and 45°C to effectively prevent the binder from aging and failing due to excessively high temperatures, and to prevent problems such as stratification and sedimentation in the slurry. At the same time, it avoids abnormal viscosity and dispersion difficulties caused by excessively low temperatures, ensuring a stable dispersion process and consistent slurry performance. The viscosity range of the slurry ensures smooth coating and uniform coating thickness, while also supporting the overlapping and forming of the linear conductive material 7, ensuring the structural integrity of the first coating 2.

[0064] Furthermore, the first and second drying processes in step S4 adopt a segmented drying method, including a low-temperature section and a high-temperature section. The temperature of the low-temperature section is 50°C to 70°C, and the temperature of the high-temperature section is 80°C to 120°C.

[0065] The low-temperature section allows the solvent in the slurry to evaporate slowly, preventing the rapid evaporation of the solvent from generating a large number of bubbles and avoiding problems such as pinholes, cracks, and peeling in the coating. The high-temperature section allows the binder to fully cure, enabling the first coating 2 preform and the second coating 3 to cure and form simultaneously, significantly enhancing the bonding force between the two coatings, avoiding delamination and peeling during the cycle, and ensuring the stability of the electrode structure.

[0066] Furthermore, after step S4, step S5 is also included: the dried electrode sheet is rolled and compacted at a temperature of 60°C to 90°C, so that the porosity of the first coating 2 is controlled at 25% to 35% and the porosity of the second coating 3 is controlled at 30% to 40%.

[0067] The rolling compaction temperature is controlled between 60°C and 90°C, falling within the category of low-temperature rolling. This allows for increased electrode areal density while preventing structural damage to the active material and softening and failure of the binder caused by high temperatures. Precise control of the porosity of the first coating 2 (25%-35%) and the second coating 3 (30%-40%) achieves a balance between conductivity and lithium-ion diffusion efficiency. The rolling compaction process increases the areal density of the electrode, enhances the amount of active material filling, and further improves the electrode's energy density.

[0068] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A low internal resistance lithium-ion battery electrode structure, comprising a current collector and an active material layer disposed on at least one surface of the current collector, characterized in that, The active material layer includes a first coating layer and a second coating layer stacked together. The first coating is located between the current collector and the second coating. The first coating includes first active material particles and a first conductive agent. The first conductive agent includes linear conductive material and dot-shaped conductive material. The linear conductive materials overlap to form a three-dimensional conductive network skeleton. The dot-shaped conductive material is distributed between and on the surface of the first active material particles and connects the first active material particles with the three-dimensional conductive network skeleton. The second coating comprises second active material particles and a second conductive agent, wherein the content of the second conductive agent in the second coating is lower than the total content of the first conductive agent in the first coating.

2. The low internal resistance lithium-ion battery electrode structure according to claim 1, characterized in that: The linear conductive material is one or more of carbon nanotubes, carbon nanofibers, or vapor-grown carbon fibers. The dotted conductive material is one or more of conductive carbon black, acetylene black, or Ketjen black.

3. The low internal resistance lithium-ion battery electrode structure according to claim 1, characterized in that: The thickness of the first coating is 1 / 5 to 1 / 3 of the total thickness of the active material layer.

4. The low internal resistance lithium-ion battery electrode structure according to claim 1, characterized in that: In the first coating, the mass of the linear conductive material accounts for 0.5% to 3% of the total solid content of the first coating, and the mass of the dot-shaped conductive material accounts for 0.5% to 2% of the total solid content of the first coating.

5. The low internal resistance lithium-ion battery electrode structure according to claim 1, characterized in that: The second coating does not contain linear conductive materials, and the second conductive agent is only a dot-shaped conductive material, and its mass accounts for 0.5% to 1.5% of the total solid content of the second coating.

6. The low internal resistance lithium-ion battery electrode structure according to claim 1, characterized in that: The current collector is a carbon-coated aluminum foil or a plain aluminum foil, and the conductive coating of the carbon-coated aluminum foil is in contact with the first coating.

7. A method for manufacturing a low internal resistance lithium-ion battery electrode structure, characterized in that: Includes the following steps: Step S1: Prepare the first slurry by mixing the first active substance, the first conductive agent containing linear conductive material and dot-shaped conductive material, the first binder and the first solvent, and by using the first dispersion process to disperse the linear conductive material and allow it to overlap to form a pre-three-dimensional network; Step S2: Prepare the second slurry by mixing the second active material, the second conductive agent, the second binder, and the second solvent, and then uniformly dispersing the components through the second dispersion process; Step S3: The first slurry prepared in step S1 is coated onto the surface of the current collector, and after a first drying treatment, a first coating preform is formed; Step S4: Coat the surface of the first coating blank with the second slurry prepared in step S2, and perform a second drying treatment to allow the first coating blank and the second coating to be cured and formed simultaneously to form an active material layer.

8. The method for manufacturing a low internal resistance lithium-ion battery electrode structure according to claim 7, characterized in that: The first dispersion process in step S1 adopts a combination of high-speed shear dispersion and ultrasonic-assisted dispersion, with the dispersion temperature controlled between 25°C and 45°C, and the viscosity of the dispersed slurry between 3000 mPa·s and 8000 mPa·s.

9. A method for manufacturing a low internal resistance lithium-ion battery electrode structure according to claim 7, characterized in that: The first and second drying processes in step S4 adopt a segmented drying method, including a low-temperature section and a high-temperature section. The temperature of the low-temperature section is 50°C to 70°C, and the temperature of the high-temperature section is 80°C to 120°C.

10. A method for manufacturing a low internal resistance lithium-ion battery electrode structure according to claim 7, characterized in that: After step S4, step S5 is also included: the dried electrode sheet is rolled and compacted at a temperature of 60°C to 90°C, so that the porosity of the first coating is controlled at 25% to 35% and the porosity of the second coating is controlled at 30% to 40%.

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