Battery cell structure, battery and electric device
Patent Information
- Application Number
- CN202522118542.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-30
- Publication Date
- 2026-10-27
- Estimated Expiration
- 2035-09-30
AI Technical Summary
然而，在实际涂布作业环节，为达成理想的削薄效果，往往需要反复进行调试操作
[0023]本实用新型的电芯结构，通过在与负极片的单面区和双面区交接形成的交界区相对应的正极活性物质层上设置绝缘层，在电芯结构的厚度方向上，绝缘层的投影至少部分覆盖交界区的投影，有效地使得该区域在充放电过程中无法进行锂离子脱嵌反应，从根源上避免了析锂风险，提升了电芯结构的安全性和可靠性，减少了因析锂导致短路、起火爆炸等安全隐患。同时，相较于涂布削薄调控，本实用新型仅需在正极片朝向交界区一侧的正极活性物质层上设置绝缘层，结构简单，无需改造现有涂布设备，有效避免了因反复调试造成的高物料损耗与时间成本。从而有效规避了因削薄不均带来的质量波动，有利于提高电芯结构的一致性与生产良率。
Smart Images
Figure CN224908058U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of battery technology, specifically relating to a cell structure, a battery, and an electrical device. Background Technology
[0002] Lithium-ion batteries, as a new type of rechargeable battery, have advantages such as high energy density and power density, high operating voltage, light weight, small size, long cycle life, good safety, and environmental friendliness. They have broad application prospects in portable electrical appliances, power tools, large-scale energy storage, and electric transportation power supplies.
[0003] Currently, most common battery cell structures employ a winding method where the positive electrode sheet wraps around the negative electrode sheet, with a negative electrode empty foil area at the head of the winding core. On the short negative electrode film surface in this area, there is a single-sided / double-sided material interface zone at the junction of the coating and the empty foil. Due to the abrupt change in the thickness of the negative electrode sheet in this interface zone, localized over- or under-voltage situations can easily occur in this area during the rolling process.
[0004] As the number of charge-discharge cycles of the battery cell increases, lithium deposition is highly likely to occur in this interface area. The deposited lithium can form lithium dendrites, which may puncture the separator, leading to a short circuit in the battery cell and causing serious safety accidents such as fire or even explosion.
[0005] To address this issue, the edges of the affected area are typically thinned during the coating stage. However, in actual coating operations, achieving the desired thinning effect often requires repeated adjustments. This process not only results in significant material waste but also consumes substantial machine time and labor costs, ultimately leading to a significant increase in overall production costs. Utility Model Content
[0006] The purpose of this utility model is to provide a battery cell structure that addresses the shortcomings of existing technologies. This structure solves the technical problem that in the existing technology, the junction area between the single and double-sided materials of the negative electrode sheet is prone to local over-voltage or under-voltage during rolling due to the sudden change in the thickness of the negative electrode sheet. As the number of charge and discharge cycles of the battery cell increases, lithium dendrites are easily deposited in this junction area, which can pierce the separator, causing short circuits, fires, and explosions.
[0007] To achieve the above objectives, the present invention adopts the following technical solution:
[0008] In a first aspect, this utility model provides a battery cell structure, including a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet, the separator, and the negative electrode sheet are stacked and wound together. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative electrode sheet has a single-sided region and a double-sided region connected to each other. The negative active material layer is disposed on one side of the negative current collector in the single-sided region, and the negative active material layer is disposed on both sides of the negative current collector in the double-sided region. The single-sided region and the double-sided region intersect to form a boundary region. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive active material layer is disposed on the surface of the positive current collector. An insulating layer is disposed on the positive active material layer on the side of the positive electrode sheet facing the boundary region. Along the thickness direction of the battery cell structure, the projection of the insulating layer at least partially covers the projection of the boundary region.
[0009] In some embodiments, one side of the positive electrode is a short film surface, and the other side of the positive electrode is a long film surface, with the insulating layer disposed on the long film surface of the positive electrode.
[0010] In some embodiments, the insulating layer has a covering area, and the projection of the covering area overlaps with the projection of the boundary area along the thickness direction of the cell structure.
[0011] In some embodiments, the insulating layer further has an extension region connected to the covering region, and the extension region extends outward from at least one end of the covering region.
[0012] In some embodiments, the length L of the insulating layer satisfies the relationship: L=K+a, and 0≤a≤2mm, where K is the width of the positive electrode sheet;
[0013] And / or, the width P of the insulating layer satisfies the relationship: 5mm≤P≤12mm;
[0014] And / or, the thickness H of the insulating layer satisfies the relationship: 10μm≤H≤20μm.
[0015] In some embodiments, the insulating layer includes a substrate layer and an adhesive layer, the substrate layer being disposed on one side of the adhesive layer, and the other side of the adhesive layer being bonded to the surface of the positive electrode sheet;
[0016] Alternatively, the insulating layer may be a polymer layer;
[0017] Alternatively, the insulating layer may be a ceramic layer.
[0018] In some embodiments, both the positive electrode and the negative electrode include alternating straight sections and arc-shaped sections, the boundary region is located on the straight section of the negative electrode, and the insulating layer is located on the straight section of the positive electrode.
[0019] In some embodiments, a negative tab is provided on the negative current collector, and a positive tab is provided on the positive current collector. Along the thickness direction of the cell structure, the projections of the insulating layer, the negative tab, and the positive tab do not overlap.
[0020] Secondly, this utility model provides a battery, including the cell structure of the above embodiments.
[0021] Thirdly, this utility model provides an electrical device, including the cell structure of the above embodiments; or, the battery of the above embodiments.
[0022] Compared with the prior art, the beneficial effects achieved by this utility model are as follows:
[0023] This novel battery cell structure incorporates an insulating layer on the positive electrode active material layer corresponding to the boundary region formed by the junction of the single-sided and double-sided regions of the negative electrode sheet. In the thickness direction of the cell structure, the projection of the insulating layer at least partially covers the projection of the boundary region. This effectively prevents lithium-ion intercalation / deintercalation reactions in this area during charging and discharging, fundamentally avoiding the risk of lithium plating and improving the safety and reliability of the cell structure. It also reduces safety hazards such as short circuits, fires, and explosions caused by lithium plating. Furthermore, compared to coating thinning control, this invention only requires an insulating layer on the positive electrode active material layer facing the boundary region of the positive electrode sheet. The structure is simple, requires no modification to existing coating equipment, and effectively avoids high material losses and time costs caused by repeated adjustments. This effectively avoids quality fluctuations caused by uneven thinning, contributing to improved cell structure consistency and production yield.
[0024] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 This is one of the structural schematic diagrams of the battery cell structure of this utility model.
[0027] Figure 2 This is the second schematic diagram of the battery cell structure of this utility model.
[0028] Figure 3 This is one of the structural schematic diagrams of the positive electrode sheet of this utility model.
[0029] Figure 4 This is the second schematic diagram of the structure of the positive electrode sheet of this utility model.
[0030] Figure 5 This is a schematic diagram of the structure of the insulating layer of this utility model.
[0031] The reference numerals in the attached figures are explained as follows:
[0032] 100. Cell structure;
[0033] 10. Positive electrode plate; 11. Positive electrode current collector; 12. Positive electrode active material layer; 13. Short film surface; 14. Long film surface; 15. Positive electrode tab;
[0034] 20. Negative electrode sheet; 21. Negative electrode current collector; 22. Negative electrode active material layer; 23. Single-sided region; 24. Double-sided region; 25. Junction region; 26. Negative electrode tab;
[0035] 30. Diaphragm;
[0036] 40. Insulating layer; 41. Covered area; 42. Extension area; 43. Substrate layer; 44. Adhesive layer;
[0037] 50. Straight section;
[0038] 60. Arc-shaped segment;
[0039] b. Thickness direction of the battery cell structure. Detailed Implementation
[0040] If certain terms are used in the specification and claims to refer to specific components, those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The term "comprising" as used throughout the specification and claims is an open-ended term and should be interpreted as "comprising but not limited to." "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error.
[0041] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be interpreted as indicating or implying relative importance.
[0042] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0043] The following will be combined with the appendix Figures 1-5 The technical solutions in the embodiments of this utility model are clearly and completely described. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. 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.
[0044] The electrical equipment of this utility model embodiment includes a cell structure 100 or a battery. The electrical equipment can be a car, mobile phone, portable device, laptop, ship, spacecraft, electric toy, and power tool, etc. Cars can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric cars, hybrid electric cars, or range-extended electric cars, etc.; spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application embodiment does not impose any special limitations on the above-mentioned electrical equipment.
[0045] The battery of this utility model embodiment includes a cell structure 100.
[0046] Please see Figures 1-5The battery cell structure 100 of this embodiment includes a positive electrode 10, a negative electrode 20, and a separator 30. The positive electrode 10, separator 30, and negative electrode 20 are stacked and wound together. The negative electrode 20 includes a negative current collector 21 and a negative active material layer 22. The negative electrode 20 has a single-sided region 23 and a double-sided region 24 connected to each other. A negative active layer is disposed on one side of the negative current collector 21 in the single-sided region 23, and a negative active material layer is disposed on both sides of the negative current collector 21 in the double-sided region 24. The negative electrode active material layer 22, the single-sided region 23 and the double-sided region 24 intersect to form a junction region 25. The positive electrode sheet 10 includes a positive electrode current collector 11 and a positive electrode active material layer 12. The positive electrode active material layer 12 is disposed on the surface of the positive electrode current collector 11. An insulating layer 40 is disposed on the positive electrode active material layer 12 on the side of the positive electrode sheet 10 facing the junction region 25. Along the thickness direction b of the cell structure 100, the projection of the insulating layer 40 at least partially covers the projection of the junction region 25.
[0047] Compared with the prior art, the cell structure 100 of this utility model, by setting an insulating layer 40 on the positive electrode active material layer 12 corresponding to the boundary region 25 formed by the intersection of the single-sided region 23 and the double-sided region 24 of the negative electrode sheet 20, ensures that the projection of the insulating layer 40 at least partially covers the projection of the boundary region 25 in the thickness direction b of the cell structure 100. This effectively prevents lithium-ion intercalation / deintercalation reactions in this area during charging and discharging, fundamentally avoiding the risk of lithium plating, improving the safety and reliability of the cell structure 100, and reducing safety hazards such as short circuits, fires, and explosions caused by lithium plating. Furthermore, compared with coating thinning control, this utility model only requires setting the insulating layer 40 on the positive electrode active material layer 12 on the side of the positive electrode sheet 10 facing the boundary region 25. The structure is simple, requires no modification to existing coating equipment, and effectively avoids high material loss and time costs caused by repeated adjustments. This effectively avoids quality fluctuations caused by uneven thinning, which is beneficial to improving the consistency and production yield of the cell structure 100.
[0048] It is understood that the negative electrode 20 has a single-sided region 23 and a double-sided region 24 connected to each other. The single-sided region 23 has a negative electrode active layer coated on one side of the negative electrode current collector 21; that is, the portion of the negative electrode 20 with a negative electrode active layer on only one side is the single-sided region 23. The double-sided region 24 has a negative electrode active layer coated on both sides of the negative electrode current collector 21; that is, the portion of the negative electrode 20 with a negative electrode active layer on both sides is the double-sided region 24.
[0049] The single-sided region 23 and the double-sided region 24 intersect to form the boundary region 25. The boundary region 25 can be understood as the part of the negative electrode sheet 20 located on both sides of the boundary between the single-sided region 23 and the double-sided region 24 in the winding direction of the cell structure 100.
[0050] In some embodiments, one side of the positive electrode 10 is a short film surface 13, and the other side is a long film surface 14. An insulating layer 40 is disposed on the long film surface 14 of the positive electrode 10. By disposing the insulating layer 40 on the long film surface 14 of the positive electrode 10, its projection in the thickness direction b of the cell structure 100 can completely cover the junction region 25. This ensures that even if a slight misalignment occurs in the electrode, the insulating layer 40 can still effectively block the lithium-ion insertion / extraction reaction, thus improving the safety and reliability of the cell structure 100.
[0051] In some embodiments, the insulating layer 40 has a covering area 41, and the projection of the covering area 41 overlaps with the projection of the boundary area 25 along the thickness direction b of the cell structure 100. By providing the covering area 41, the insulating layer 40 directly acts on the boundary area 25, effectively ensuring that the insulating layer 40 precisely covers the boundary area 25. This effectively blocks ion migration in this area during charging and discharging, fundamentally preventing lithium plating.
[0052] In some embodiments, the insulating layer 40 further has an extension region 42 connected to the covering region 41, and the extension region 42 extends outward from at least one end of the covering region 41. The extension region 42 provides tolerance space for the winding alignment process. Even if a slight axial misalignment occurs during electrode assembly, the extension region 42 ensures that the junction area 25 is always completely covered by the insulating layer 40, avoiding protection blind spots caused by alignment deviations and effectively improving the reliability of the cell structure 100.
[0053] In some embodiments, the length L of the insulating layer 40 satisfies the relationship: L=K+a, and 0≤a≤2mm, where K is the width of the positive electrode 10; and / or, the width P of the insulating layer 40 satisfies the relationship: 5mm≤P≤12mm; and / or, the thickness H of the insulating layer 40 satisfies the relationship: 10μm≤H≤20μm.
[0054] By setting L = K + a, and 0 ≤ a ≤ 2 mm, it is effectively ensured that the insulating layer 40 completely covers the positive electrode 10 and the junction area 25 along its length, and the allowance a provides process tolerance. This effectively avoids the exposure of the junction area 25 due to minor misalignments during electrode winding or alignment, thus effectively improving the reliability of the cell structure 100. Simultaneously, the setting of 0 ≤ a ≤ 2 mm ensures safety redundancy while avoiding material waste. Regarding the width P of the insulating layer 40, if P is too narrow, the junction area 25 is easily exposed due to minor misalignments during electrode winding or alignment, resulting in the insulating layer 40 not completely covering the junction area 25. If P is too wide, the cell capacity and energy density will be excessively sacrificed. Therefore, setting 5 mm ≤ P ≤ 12 mm effectively ensures that the insulating layer 40 not only completely covers the junction area 25 but also reduces the space occupied by the cell structure 100. By setting the thickness H of the insulating layer 40, if the thickness H is too thin, the insulating layer 40 cannot form a physical barrier to prevent lithium-ion migration; if the thickness H is too thick, it will increase the volume and weight of the battery cell and reduce its energy density. By setting the thickness H to 10μm≤H≤20μm, the insulating layer 40 can effectively prevent lithium-ion migration while also reducing the space occupied by the battery cell structure 100.
[0055] Furthermore, the width P of the insulating layer 40 is 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, or 12 mm, but is not limited to the listed values; other values within the range are also applicable. The thickness H of the insulating layer 40 is 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, or 20 μm, but is not limited to the listed values; other values within the range are also applicable.
[0056] In some embodiments, the insulating layer 40 includes a substrate layer 43 and an adhesive layer 44, with the substrate layer 43 disposed on one side of the adhesive layer 44 and the other side of the adhesive layer 44 bonded to the surface of the positive electrode 10; or, the insulating layer 40 is a polymer layer; or, the insulating layer 40 is a ceramic layer. This effectively increases the structural diversity of the insulating layer 40, allowing for selection based on actual needs during use.
[0057] Furthermore, the substrate layer 43 is a polyester film layer, a polyimide film layer, or a polypropylene layer. The adhesive layer 44 is an epoxy resin layer, an acrylate adhesive layer, or a polyolefin hot melt adhesive layer. The polymer layer is a polyester layer, a polyimide layer, or a polyolefin layer. The ceramic layer is an alumina layer, a silicon oxide layer, or a boron nitride layer.
[0058] In some embodiments, both the positive electrode 10 and the negative electrode 20 include alternating straight sections 50 and arc-shaped sections 60. A junction region 25 is located on the straight section 50 of the negative electrode 20, and an insulating layer 40 is located on the straight section 50 of the positive electrode 10. The straight section 50 is the region where the stress distribution of the electrode is relatively uniform after winding, and the interface contact is most stable. Providing the insulating layer 40 and the junction region 25 on the straight section 50 ensures a stable correspondence between the insulating layer 40 and the junction region 25, effectively avoiding fluctuations in the protection distance that may occur due to changes in the curvature of the arc-shaped section 60, thereby improving the protective effect of the insulating layer 40.
[0059] In some embodiments, a negative electrode tab 26 is provided on the negative electrode current collector 21, and a positive electrode tab 15 is provided on the positive electrode current collector 11. Along the thickness direction b of the cell structure 100, the projections of the insulating layer 40, the negative electrode tab 26, and the positive electrode tab 15 do not overlap. This effectively keeps the insulating layer 40 away from the area of the tab, thereby avoiding the introduction of new thickness differences into the cell structure 100 due to local expansion caused by the swelling or dissolution of the tab adhesive.
[0060] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention.
Claims
1. A battery cell structure, characterized in that: The device includes a positive electrode (10), a negative electrode (20), and a separator (30). The positive electrode (10), the separator (30), and the negative electrode (20) are stacked and wound together. The negative electrode (20) includes a negative current collector (21) and a negative active material layer (22). The negative electrode (20) has a single-sided region (23) and a double-sided region (24) connected to each other. The negative active material layer is disposed on one side of the negative current collector (21) in the single-sided region (23), and the negative active material layer (22) is disposed on both sides of the negative current collector (21) in the double-sided region (24). The single-sided region (23) and the double-sided region (24) intersect to form a boundary region (25). The positive electrode sheet (10) includes a positive current collector (11) and a positive active material layer (12). The positive active material layer (12) is disposed on the surface of the positive current collector (11). An insulating layer (40) is disposed on the positive active material layer (12) on the side of the positive electrode sheet (10) facing the boundary region (25). Along the thickness direction (b) of the cell structure (100), the projection of the insulating layer (40) at least partially covers the projection of the boundary region (25).
2. The cell structure as described in claim 1, characterized in that: One side of the positive electrode (10) is a short film surface (13), and the other side of the positive electrode (10) is a long film surface (14). The insulating layer (40) is disposed on the long film surface (14) of the positive electrode (10).
3. The cell structure as described in claim 1, characterized in that: The insulating layer (40) has a covering area (41) along the thickness direction (b) of the cell structure (100), and the projection of the covering area (41) overlaps with the projection of the boundary area (25).
4. The cell structure as described in claim 3, characterized in that: The insulating layer (40) also has an extension region (42) connected to the covering region (41), and the extension region (42) extends outward from at least one end of the covering region (41).
5. The cell structure as described in claim 1, characterized in that: The length L of the insulating layer (40) satisfies the following relationship: L=K+a, and 0≤a≤2mm, where K is the width of the positive electrode (10); And / or, the width P of the insulating layer (40) satisfies the relationship: 5mm≤P≤12mm; And / or, the thickness H of the insulating layer (40) satisfies the relationship: 10μm≤H≤20μm.
6. The cell structure as described in claim 1, characterized in that: The insulating layer (40) includes a substrate layer (43) and an adhesive layer (44). The substrate layer (43) is disposed on one side of the adhesive layer (44), and the other side of the adhesive layer (44) is attached to the surface of the positive electrode (10). Alternatively, the insulating layer (40) may be a polymer layer; Alternatively, the insulating layer (40) may be a ceramic layer.
7. The cell structure as described in claim 1, characterized in that: Both the positive electrode (10) and the negative electrode (20) include alternating straight sections (50) and arc-shaped sections (60), the junction area (25) is located on the straight section (50) of the negative electrode (20), and the insulating layer (40) is located on the straight section (50) of the positive electrode (10).
8. The cell structure as described in claim 1, characterized in that: A negative electrode tab (26) is provided on the negative electrode current collector (21), and a positive electrode tab (15) is provided on the positive electrode current collector (11). Along the thickness direction (b) of the cell structure (100), the projections of the insulating layer (40), the negative electrode tab (26), and the positive electrode tab (15) do not overlap.
9. A battery, characterized in that: Includes the cell structure described in any one of claims 1 to 8.
10. An electrical appliance, characterized in that: It includes the cell structure described in any one of claims 1 to 8; or the battery described in claim 9.