Pole piece, battery cell and battery
By setting etching trenches of different depths on the active material layer of the electrode, the distribution of lithium ions is optimized, solving the problem that uniform hole depth design cannot improve the charging rate, and achieving more efficient lithium ion insertion and improved battery performance.
Patent Information
- Application Number
- CN202422333780.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-24
- Publication Date
- 2025-11-11
- Estimated Expiration
- 2034-09-24
AI Technical Summary
In existing technologies, uniform hole depth design cannot be optimized for uneven lithium-ion distribution, resulting in insufficient improvement in charging rate.
Etching trenches of different depths are set on the active material layer of the electrode. The etching trench depth in the conductive area of the electrode tab is greater than that in the non-electrode area to optimize lithium ion distribution and transport path.
By optimizing lithium-ion distribution, the insertion speed is improved, transmission bottlenecks and polarization are reduced, and the charging efficiency and performance of the battery are enhanced.
Smart Images
Figure CN223539606U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery technology, and in particular to an electrode, a cell, and a battery. Background Technology
[0002] As a primary energy storage device, batteries face increasingly higher demands for fast charging. Achieving fast battery charging can not only improve device efficiency but also reduce user waiting time. The rate at which lithium ions are intercalated into the active material layer is also one of the factors affecting charging speed.
[0003] To address the issue of lithium-ion insertion speed in the active material layer, a method has been proposed to construct etching grooves on the active material layer of the electrode. By forming etching grooves on the active material layer, the contact area between lithium ions and the active material layer can be increased, thereby accelerating lithium-ion insertion and improving battery charging performance to some extent, resulting in smoother lithium-ion transport during charging.
[0004] However, the depth of the etched trenches formed on the active material layer using related technologies is usually uniform. Since the lithium-ion flow rate near the tabs is higher than in other areas, this uniform depth design cannot be optimized for this uneven lithium-ion distribution, resulting in the charging rate not being maximized. Utility Model Content
[0005] The main purpose of this invention is to propose an electrode that aims to solve the problem that a uniform hole depth design cannot be optimized for uneven lithium-ion distribution and thus cannot maximize the charging rate.
[0006] To achieve the above objectives, this utility model proposes an electrode sheet, which includes:
[0007] A current collector having opposing first and second surfaces, each having connected tab conductive regions and non-tab regions.
[0008] An active material layer, wherein the active material layer is coated on at least one of the first surface and the second surface;
[0009] The surface of the active material layer corresponding to the tab conductive region is constructed with a plurality of first etching grooves, and the surface of the active material layer located in the non-tab region is constructed with a plurality of second etching grooves, wherein the depth of the first etching grooves is greater than the depth of the second etching grooves.
[0010] In some embodiments, the thickness of the active material layer is T, and the depth of the first etching trench is H, wherein the depth H of the first etching trench is 40%-60% of the thickness of the active material layer T.
[0011] In some embodiments, the depth of the second etching trench is 20%T-60%T of the thickness of the active material layer.
[0012] In some embodiments, a plurality of first etching grooves are uniformly and spaced along the width direction of the current collector and on the surface of the active material layer corresponding to the electrode conductive region, and the spacing between the plurality of first etching grooves is 0.8-2.5 mm.
[0013] In some embodiments, a plurality of second etching grooves are uniformly spaced along the width direction of the current collector and on the surface of the active material layer corresponding to the non-tab region, and the spacing between the plurality of second etching grooves is 0.8-2.5 mm.
[0014] In some embodiments, the distance between the second etched groove near the tab conductive region and the first etched groove near the non-tab region is greater than 2.5 mm.
[0015] In some embodiments, the width of the plurality of first etching grooves is 30-150 μm;
[0016] And / or, the width of the plurality of second etched parts is 30-150 μm.
[0017] In some embodiments, both back surfaces of the current collector are coated with the active material layer.
[0018] This invention further proposes a battery cell, including a separator and an electrode sheet as described in the foregoing embodiment, wherein the separator is wound or folded along with the electrode sheet to form the battery cell.
[0019] The present invention further proposes a battery, including a casing and a battery cell as described in the foregoing embodiment, wherein the casing is used to encapsulate the battery cell.
[0020] The beneficial effects of this invention are as follows: By setting etching trenches of different depths on the active material layer, with the first etching trench depth in the tab conductive region being greater than the second etching trench depth in the non-tab region, the uneven distribution of lithium ions on the electrode is effectively optimized. This design allows the tab conductive region to better accommodate and guide higher lithium ion flow rates, reducing transmission bottlenecks and polarization phenomena caused by excessively high local current densities. Simultaneously, the non-tab region maintains a shallower etching trench depth, preserving the mechanical strength and structural stability of the electrode. This overall maximizes the lithium ion insertion speed and charging rate, improving the battery's charging efficiency and performance. Attached Figure Description
[0021] Figure 1 This is a top view of the electrode sheet in one embodiment of the present invention;
[0022] Figure 2This is a schematic diagram of the electrode sheet in one embodiment of the present invention;
[0023] Figure 3 This is a schematic diagram of the electrode sheet in another embodiment of the present invention.
[0024] Explanation of icon numbers:
[0025] 10. Electrode; 100. Current collector; 101. First surface; 102. Second surface; 111. Electrode conductive area; 111a. First etching groove; 112. Non-electrode area; 112a. Second etching groove; 120. Active material layer; 200. Separating membrane; 300. Outer shell; 400. Electrode.
[0026] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0027] The solutions in the embodiments of this utility model 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 utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.
[0028] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.
[0029] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.
[0030] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.
[0031] The battery charging process is the reverse of an electrochemical reaction. An external power source applies voltage, causing lithium ions to migrate from the positive electrode to the negative electrode, thus storing electrical energy. During charging, the external power source provides electrical energy to drive lithium ions out of the positive electrode. In the positive electrode material (such as lithium cobalt oxide LiCoO2), lithium ions escape the lattice of the positive electrode, losing electrons in the process. These lithium ions then enter the electrolyte and migrate through the separator to the negative electrode.
[0032] In the negative electrode (usually graphite), lithium ions are embedded in the interlayer structure of graphite and combine with electrons flowing in from the external circuit to form a stable lithium intercalation compound (such as LiC6). Electrons are then pushed from the positive electrode to the negative electrode through the external circuit (electrically connected to the external circuit via tabs), completing charge balance and ensuring smooth binding of lithium ions and electrons at the negative electrode. At this time, the metal ions in the positive electrode material are oxidized, and the chemical potential energy increases.
[0033] It is evident that the tabs are the main entry and exit points of current, and current is more likely to concentrate in these areas, resulting in a high current density in these areas. Areas with high current density attract more lithium ions, which makes the lithium ion flow near the tabs significantly greater than that in non-tab areas.
[0034] If lithium ions accumulate in large quantities near the tabs and their insertion into the active material layer is slow, the current density in the local area will continue to increase, leading to increased localized overheating and polarization of the electrode. This limits the overall reaction rate of the electrode and reduces charging efficiency. In other words, if the insertion rate does not match the lithium ion flow rate, lithium ions may accumulate in the electrolyte, creating a transport bottleneck. This bottleneck increases the battery's internal resistance, making the charging process even slower and reducing overall efficiency.
[0035] Therefore, it is necessary to optimize the lithium-ion insertion rate, especially in high-flow areas (such as near the tabs), to make the charging process more balanced. The embodiments of this invention utilize etched holes of different depths on the active material layer; that is, the depth of the first etched hole in the tab conductive area is greater than the depth of the second etched hole in the non-tab area. This effectively optimizes the lithium-ion insertion rate into the active material layer, thereby improving charging efficiency. See details below. Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the electrode sheet in one embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of the electrode sheet in one embodiment of the present invention.
[0036] An embodiment of this utility model provides an electrode sheet, which includes:
[0037] The current collector 100 has a first surface 101 and a second surface 102 with opposite surfaces, and both the first surface 101 and the second surface 102 have connected tab conductive regions 111 and non-tab regions 112.
[0038] An active material layer 120 is coated on at least one of the first surface 101 and the second surface 102.
[0039] The surface of the active material layer 120 corresponding to the tab conductive region 111 is constructed with a plurality of first etching grooves 111a, and the surface of the active material layer 120 located in the non-tab region 112 is constructed with a plurality of second etching grooves 112a, wherein the depth of the first etching grooves 111a is greater than the depth of the second etching grooves 112a.
[0040] In this embodiment, the current collector 100 is mainly used to collect and conduct electrons, thus playing a conductive role. The material selection depends on the type of electrode 10. For example, when used as a positive electrode 10, the current collector 100 can be made of materials such as aluminum foil or aluminum mesh; when used as a negative electrode 10, the current collector 100 can be made of materials such as copper foil or copper mesh.
[0041] The active material layer 120 serves to provide sites for lithium-ion insertion and extraction, and its material varies depending on the type of electrode 10. For the positive electrode 10, the active material layer 120 can use positive active materials such as lithium iron phosphate, lithium cobalt oxide, or ternary materials; for the negative electrode 10, the active material layer 120 can use negative active materials such as graphite or silicon carbide. The first etching groove 111a and the second etching groove 112a located on the surface of the active material layer 120 can be formed by laser etching, chemical etching, mechanical processing, etc.
[0042] During operation, when the battery is charging, lithium ions are extracted from the positive electrode, pass through the electrolyte and separator, migrate to the negative electrode, and embed themselves in the active material layer 120 of the negative electrode. Since the tab conductive region 111 is the main area for current entry and exit, the current density and lithium ion flow rate are relatively high. By providing a deep first etched groove 111a in the tab conductive region 111, the surface area of the active material in this region can be increased, which means increasing the embedding path, reducing the lithium ion transport impedance, and thus optimizing the lithium ion embedding rate. The increased embedding rate means that lithium ions can enter the negative electrode active material layer 120 more quickly, combine with electrons to form a stable lithium intercalation compound, reduce the residence time of lithium ions in the electrolyte, and avoid transport bottlenecks and localized overheating.
[0043] Meanwhile, a shallower second etching trench 112a is provided in the non-tab region 112, which provides a lithium-ion insertion channel while maintaining the thickness of the active material layer 120, ensuring the mechanical strength and structural stability of the electrode. The two etching trenches of different depths work together to optimize the lithium-ion insertion rate of the entire electrode. Since the lithium-ion insertion rate in the negative electrode active material layer 120 directly affects the charging rate, increasing the insertion rate can reduce energy loss caused by lithium-ion transport impedance during charging, improve the utilization efficiency of the charging current, and thus significantly improve the charging efficiency of the battery.
[0044] In this embodiment, by setting etching trenches of different depths in the tab conductive region 111 and the non-tab region 112, the distribution and transport path of lithium ions are specifically optimized. The deeper first etching trench 111a effectively addresses the high current density requirement of the tab conductive region 111, improving the lithium ion insertion speed in this region and avoiding transport bottlenecks. The shallower second etching trench 112a, while ensuring the stability of the electrode structure, improves the utilization rate of the non-tab region 112. Thus, the overall design maximizes the battery's charging rate performance and enhances its fast charging capability.
[0045] Continue reading Figure 2 In this embodiment, the thickness of the active material layer 120 is T, the depth of the first etching trench 111a is H, and the depth H of the first etching trench 111a is 40%-60% of the thickness of the active material layer 120.
[0046] In this embodiment, the thickness of the active material layer 120 is T. For example, T can be 80 μm, 100 μm, or 120 μm, etc. The depth H of the first etching trench 111a is 40%T to 60%T of the thickness of the active material layer 120, that is, when T is 100 μm, H is 40 μm to 60 μm. By setting the depth of the first etching trench 111a to a certain proportion of the thickness of the active material layer 120, the lithium-ion insertion rate can be optimized while ensuring the mechanical strength of the electrode.
[0047] For example, when the thickness of the active material layer 120 is 100 μm and the depth of the first etch trench 111a is 60 μm to 40 μm, the depth of the etch trench in the tab conductive region 111 occupies most of the active material layer 120. This design allows lithium ions to have a shorter transport path in the high-flow region (near the tab 400), reducing transport impedance and improving the insertion speed.
[0048] In some embodiments, the depth of the second etching trench 112a is 20%-60% of the thickness of the active material layer 120.
[0049] In this embodiment, the depth of the second etching trench 112a is 20%T to 60%T of the thickness of the active material layer 120. The second etching trench 112a is shallower than the first etching trench 111a. This design provides an appropriate etching depth in the non-tab region 112 to meet the functional requirements of different areas.
[0050] Specifically, in the non-tab region 112, the lithium-ion flow rate is relatively small. The shallow trench design provides the necessary lithium-ion insertion channels while avoiding the loss of active material caused by excessive etching, thus ensuring the battery's capacity and energy density.
[0051] The shallower second etch groove 112a retains more of the active material layer 120 thickness in the non-tab region 112, enhancing the mechanical strength and structural stability of the electrode and preventing active material detachment or electrode breakage due to over-etching. Combined with the deeper groove (first etch groove 111a) in the tab conductive region 111, this results in a more balanced lithium-ion insertion rate across the entire electrode 10. This avoids localized polarization and battery performance degradation caused by mismatched lithium-ion insertion rates.
[0052] In this way, the shallow depth of the second etching trench 112a meets the requirements for lithium-ion transport while maintaining the thickness of the active material layer 120 and the mechanical properties of the electrode. This ensures both high capacity and high energy density of the battery, while also improving charging efficiency and overall battery performance, achieving a balance between performance and stability.
[0053] Continue reading Figure 2 In this embodiment, a plurality of first etching grooves 111a are uniformly and spaced along the width direction of the current collector 100 and the surface of the active material layer 120 corresponding to the electrode conductive region 111, and the spacing between the plurality of first etching grooves 111a is 0.8-2.5mm.
[0054] In this embodiment, by arranging multiple first etching trenches 111a at a certain interval in the electrode conductive region 111, the lithium-ion transport path in this region can be further optimized, the current density can be evenly distributed, and the risk of local overheating and polarization can be reduced.
[0055] Specifically, the spacing of the first etched grooves 111a can be adjusted according to the battery design requirements. A smaller spacing (e.g., 0.8 mm) helps to provide more lithium-ion insertion channels in the electrode conductive region 111, adapting to the fast charging requirements under high current density; a larger spacing (e.g., 2.5 mm) ensures lithium-ion transport efficiency while maintaining the mechanical strength of the active material layer 120, preventing structural fragility caused by excessive etching.
[0056] This embodiment fully leverages the role of etching grooves in optimizing lithium-ion transport and current distribution by constructing multiple first etching grooves 111a at intervals in the electrode conductive region 111, with a spacing of 0.8-2.5 mm. This design improves charging rate performance while also considering the mechanical strength and manufacturing feasibility of the electrode.
[0057] Furthermore, the arrangement of the multiple second etching grooves 112a is the same as that of the first etching groove 111a. Specifically, the surface of the active material layer located in the non-tab region is uniformly spaced with multiple second etching grooves, and the spacing between the multiple second etching grooves is 0.8-2.5mm.
[0058] In some embodiments, the distance between the second etching groove 112a near the tab conductive region 111 and the first etching groove 111a near the non-tab region 112 is greater than 2.5 mm.
[0059] In this embodiment, by maintaining an appropriate distance between the tab conductive region 111 and the non-tab region 112, the electrochemical performance and mechanical stability of the electrode can be optimized.
[0060] Specifically, maintaining a certain thickness of the active material layer 120 between the tab conductive region 111 and the non-tab region 112 can prevent structural fragility caused by excessive etching, and enhance the mechanical strength and stability of the electrode. For example, the spacing between the second etching groove 112a near the tab conductive region 111 and the first etching groove 111a near the non-tab region 112 is 2.6 mm, 2.7 mm, etc. A reasonable spacing design can reduce the excessive exposure of the electrode surface area to the electrolyte, reduce the probability of side reactions, and extend the cycle life of the battery.
[0061] In some embodiments, the width of the plurality of first etching grooves 111a is 30-150 μm;
[0062] And / or, the width of multiple second etches is 30-150 μm.
[0063] In this embodiment, by setting the width of the etching trench in the range of 30-150μm, sufficient lithium-ion insertion channels can be provided while maintaining the mechanical strength and structural integrity of the active material layer 120.
[0064] Specifically, the etching trench width is set to 30-150 μm because an etching trench with a width of 30-150 μm can form a clear and continuous channel, allowing lithium ions to smoothly pass through the electrolyte and quickly embed into the active material layer 120. This helps to reduce the lithium ion transport impedance, increase the embedding speed, and thus improve charging efficiency.
[0065] Furthermore, excessively wide etching trenches may weaken the structural stability of the active material layer 120, leading to brittleness and detachment of the electrode material. Therefore, controlling the width of the etching trenches to within 150 μm can avoid excessive weakening of the active material layer 120 and ensure that the electrode has sufficient mechanical strength and durability.
[0066] See Figure 3 In this embodiment, both the first surface 101 and the second surface 102 of the current collector 100 are coated with an active material layer 120. That is, the first surface 101 and the second surface 102 of the current collector 100 are simultaneously coated with the active material layer 120, forming a double-sided electrode structure. This design allows the electrode to provide more active material within a limited volume, thereby improving the battery's capacity and energy density.
[0067] In this embodiment, the current collector 100 is coated with an active material layer 120 on both sides, allowing the electrode per unit area to carry more active material, thereby improving the energy density and capacity of the battery. This is highly advantageous for battery applications requiring high capacity and high energy density.
[0068] Meanwhile, double-sided coating allows for a more uniform current distribution within the electrode, reducing current density concentration, lowering internal electrode resistance, and improving the battery's rate performance and charge / discharge efficiency. During charge and discharge, the expansion and contraction of the active material layer 120 can cancel each other out on both sides, reducing electrode deformation and stress concentration, and improving the battery's cycle life and stability.
[0069] During the manufacturing process, processes such as coating, drying, and compaction can be used to uniformly coat the active material slurry onto both sides of the current collector 100. Subsequently, according to design requirements, a first etching groove 111a and a second etching groove 112a are formed on the active material layer 120 to optimize the lithium ion transport path and insertion speed.
[0070] In this embodiment, an active material layer 120 is coated on both back-to-back surfaces of the current collector 100 to construct a double-sided electrode structure, thereby improving the battery's capacity and performance.
[0071] This utility model further proposes a battery cell, including a separator 200 and an electrode 10 as described in the foregoing embodiments. The specific structure of the electrode 10 is as described in the foregoing embodiments. Since this battery cell adopts all the technical solutions of all the foregoing embodiments, it has at least all the technical effects brought about by the technical solutions of the foregoing embodiments, and will not be described in detail here. The separator 200 is wound or folded along with the electrode 10 to form the battery cell, ensuring electrical isolation between the positive and negative electrodes while allowing lithium ions to pass freely.
[0072] By setting a relatively deep first etched trench 111a in the tab conductive region 111, the lithium-ion insertion speed in this region is optimized to meet the fast charging requirements under high current density. The shallow trench design in the non-tab region 112 maintains the thickness and mechanical strength of the active material layer 120. Overall, the charging efficiency of the cell is significantly improved.
[0073] The varying depths of the etched trenches optimize the lithium-ion transport path within the electrodes, reducing transport impedance. This results in better performance of the battery cell during high-rate charging and discharging, meeting the needs of applications requiring fast charging and high-current discharging.
[0074] This utility model further proposes a battery including the battery cell of the aforementioned embodiments. The specific structure of the battery cell is as described in the above embodiments. Since this battery adopts all the technical solutions of all the above embodiments, it has at least all the technical effects brought about by the technical solutions of the above embodiments, which will not be repeated here. The outer casing 300 is used to encapsulate the battery cell to protect it from the influence of the external environment and ensure the safety and reliability of the battery.
[0075] In this embodiment, by optimizing the design of the electrode 10 and the cell structure, the battery's charging efficiency, rate performance, and cycle life are significantly improved. The enhanced fast-charging capability allows the battery to better meet the demands of high-performance devices.
[0076] The above description is only a part or preferred embodiment of this utility model. Neither the text nor the drawings should limit the scope of protection of this utility model. All equivalent structural transformations made using the content of this utility model specification and drawings under the overall concept of this utility model, or direct / indirect applications in other related technical fields, are included within the scope of protection of this utility model.
Claims
1. An electrode sheet, characterized in that, include: A current collector having opposing first and second surfaces, each having connected tab conductive and non-tab regions. An active material layer is coated on at least one of the first surface and the second surface; The surface of the active material layer corresponding to the tab conductive region is constructed with a plurality of first etching grooves, and the surface of the active material layer located in the non-tab region is constructed with a plurality of second etching grooves, wherein the depth of the first etching grooves is greater than the depth of the second etching grooves.
2. The electrode sheet according to claim 1, characterized in that, The thickness of the active material layer is T, and the depth of the first etching trench is H, wherein the depth H of the first etching trench is 40%T-60%T of the thickness of the active material layer.
3. The electrode sheet according to claim 2, characterized in that, The depth of the second etching trench is 20%T-40%T of the thickness of the active material layer.
4. The electrode sheet according to claim 1, characterized in that, A plurality of first etching grooves are uniformly and spaced along the width direction of the current collector and on the surface of the active material layer corresponding to the electrode conductive region, with the spacing between the plurality of first etching grooves being 0.8-2.5 mm.
5. The electrode sheet according to claim 1 or 4, characterized in that, A plurality of second etching grooves are uniformly spaced along the width direction of the current collector and on the surface of the active material layer corresponding to the non-tab region, with the spacing between the plurality of second etching grooves being 0.8-2.5 mm.
6. The electrode sheet according to claim 5, characterized in that, The distance between the second etching groove near the electrode conductive area and the first etching groove near the non-electrode area is greater than 2.5 mm.
7. The electrode sheet according to claim 6, characterized in that, The width of the plurality of first etching grooves is 30-150 μm; and / or, The width of the plurality of second etched sections is 30-150 μm.
8. The electrode sheet according to claim 7, characterized in that, The first and second surfaces of the current collector are both coated with the active material layer.
9. A battery cell, characterized in that, It includes a separator and an electrode as described in any one of claims 1 to 8, wherein the separator is wound or folded along with the electrode to form a battery cell.
10. A battery, characterized in that, It includes a housing and a battery cell as described in claim 9, wherein the housing is used to encapsulate the battery cell.