Pole piece, battery comprising same and electronic device

Abstract

The utility model provides a kind of pole piece and including its battery, electronic device, pole piece includes: current collector, including coating area and uncoated area, coating area includes sequentially adjacent setting active material layer, first insulating part and second insulating part along preset direction;The thickness of first insulating part is greater than the thickness of second insulating part, along thickness direction, first insulating part includes first insulating layer and second insulating layer;Tab, tab projects from current collector main body along preset direction, current collector main body includes active material layer coverage area and transition zone between active material layer and tab, transition zone extends from one end of current collector to the other end along perpendicular to preset direction, part first insulating part is located on tab, part first insulating part is located on transition zone, in the thickness direction of current collector, the orthographic projection of first insulating part covers the R angle of tab. Through the pole piece and including its battery, electronic device of the application, can reduce tab burr under the premise of reducing uncoated area fold, fold.

Description

Technical Field

[0001] This utility model relates to the field of secondary battery technology, specifically to an electrode sheet and a battery and electronic device including the electrode sheet. Background Technology

[0002] Lithium-ion batteries are widely used in new energy vehicles, consumer electronics, and energy storage systems due to their advantages such as high energy density, rechargeability, safety, and environmental friendliness. Electrodes are a crucial component of lithium-ion batteries. Electrodes typically consist of an active material layer, an insulating layer, and an uncoated area. However, the uncoated area is prone to problems such as edge curling and wrinkling. Furthermore, electrode fabrication usually involves processes such as rolling, slitting, and die-cutting. During die-cutting to form the tab, a radius (R-angle) is formed at the shoulder of the tab. The size of the R-angle and the thickness at the shoulder location can lead to problems such as burrs on the cut edges, tab breakage, electrochemical risks, and increased costs. Utility Model Content

[0003] This utility model proposes an electrode sheet and a battery or electronic device including the electrode sheet. By setting a first insulating part and a second insulating part with a thickness difference, the first insulating part between the active material layer and the second insulating part supports the uncoated area. Under the premise that the first insulating part and the second insulating part work together to reduce wrinkles at the junction of the uncoated area and the second insulating part or reduce the folding of the uncoated area, the thicker first insulating part can also reduce the generation of die-cutting burrs.

[0004] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution.

[0005] This utility model also provides an electrode sheet, comprising at least:

[0006] The current collector includes a coated area and an uncoated area. The coated area includes an active material layer, a first insulating part, and a second insulating part disposed on at least one side of the current collector along a predetermined direction in the thickness direction.

[0007] In the thickness direction of the current collector, the thickness of the first insulating portion is greater than the thickness of the second insulating portion;

[0008] The electrode tab protrudes from the current collector along the preset direction. A transition zone is provided between the electrode tab and the active material layer. The second insulating portion and a portion of the first insulating portion are located on the same side of the electrode tab in the thickness direction. A portion of the first insulating portion is located on the surface of the transition zone. In the thickness direction of the current collector, the orthographic projection of the first insulating portion covers the R-angle of the electrode tab.

[0009] In one embodiment of this utility model, along the preset direction, the width of the first insulating part is W1mm, satisfying 0.3≤R / W1≤0.9; or, the radius R of the R angle is 3mm-8mm.

[0010] In one embodiment of this utility model, the value of W1 ranges from 1mm to 10mm.

[0011] In one embodiment of this utility model, along the preset direction, the width of the transition zone is d mm, satisfying 0.1 ≤ d / W1 ≤ 0.7; or

[0012] The value of W1 ranges from 1mm to 10mm.

[0013] In one embodiment of this utility model, along the preset direction, the total width D of the second insulating portion and part of the first insulating portion on the electrode tab is 4mm-24mm.

[0014] In one embodiment of this utility model, the first insulating layer and the active material layer are spaced apart;

[0015] Along the preset direction, the second insulating portion and the first insulating layer are obtained by applying the same slurry in one step.

[0016] In one embodiment of the present invention, in the thickness direction of the current collector, the overlapping range of the orthographic projections of the first insulating layer and the second insulating layer covers the transition region away from the side of the active material layer.

[0017] In one embodiment of this utility model, along the preset direction, the width of the first insulating part is W1mm, the width of the second insulating part is W2mm, and the width of the uncoated area is W3mm, satisfying 1.5≤W3 / W1≤10 and 1.6≤W3 / W2≤25.

[0018] This utility model also provides a battery, comprising at least:

[0019] A housing with an opening at the top;

[0020] Electrode assembly disposed within the housing; and

[0021] A cover plate assembly that seals the upper opening, the cover plate assembly including an adapter piece, the width direction of the adapter piece including a first electrode lug welding portion and a second electrode lug welding portion symmetrically arranged along the length direction of the adapter piece;

[0022] The electrode assembly is formed by layering a positive electrode sheet, a separator, and a negative electrode sheet and then winding or stacking them. The positive electrode sheet is the electrode sheet described in the above-mentioned item. Along a predetermined direction, the electrode assembly includes a body and an electrode tab. The electrode tab includes an uncoated area, a second insulating portion disposed on one side of the electrode tab in the same thickness direction, and a portion of the first insulating portion.

[0023] The number of electrode assemblies is two sets. The tabs of one set of electrode assemblies and the tabs of the other set of electrode assemblies are bent relative to each other and then welded to the first tab welding part and the second tab welding part of the adapter piece, respectively.

[0024] In one embodiment of the present invention, the electrode assembly includes a first adhesive tape disposed on the side of the tab facing away from the cover plate assembly. The first adhesive tape includes a first adhesive area, a second adhesive area, and a non-adhesive area located between the first adhesive area and the second adhesive area. The first adhesive area covers the main body, and the second adhesive area covers the uncoated area. In the thickness direction of the electrode assembly, the orthographic projections of the first insulating portion and the second insulating portion are completely located within the non-adhesive area.

[0025] This utility model also provides an electronic device, including the battery described above.

[0026] In summary, the electrode sheet and the battery and electronic device including it provided by this utility model, by setting a first insulating part and a second insulating part with a thickness difference between the active material layer and the uncoated area, the first insulating part between the active material layer and the second insulating part can support the uncoated area. When the electrode sheet is used to assemble bare cells for bundling when there is a thickness difference between the first insulating part and the second insulating part, the thickness transition from the first insulating part to the second insulating part can disperse stress, reduce wrinkles at the junction of the uncoated area and the second insulating part, or reduce the folding of the uncoated area. At the same time, the orthographic projection of the first insulating part covers the R-corner of the tab. During die-cutting, the thickness at the root of the tab is larger, which can reduce the generation of die-cutting burrs. Moreover, the R-corner is completely located at the first insulating part, which can avoid stress concentration points in the R-corner area of ​​the tab due to the thickness gradient difference, thereby avoiding cracking at the root of the tab due to stress concentration. It also ensures that the R-corner area occupies a sufficiently wide first insulating part, thereby playing a role in supporting the tab, preventing the tab from folding or collapsing, and improving the safety of the battery. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments 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.

[0028] Figure 1 This is a schematic diagram of an electrode sheet in one embodiment.

[0029] Figure 2 This is a schematic diagram of the tabs on the electrode sheet in one embodiment.

[0030] Figure 3 As in one embodiment, along Figure 1 A cross-sectional view of the AA-direction electrode.

[0031] Figure 4 As in one embodiment, along Figure 1 A cross-sectional view of the AA-direction electrode.

[0032] Figure 5 This is a schematic diagram of a battery in one embodiment.

[0033] Figure 6 This is a schematic diagram of an electrode assembly in one embodiment.

[0034] Figure 7 This is a schematic diagram of the electrode assembly in another embodiment.

[0035] Figure 8 This is a schematic diagram of the negative electrode sheet in one embodiment.

[0036] Figure 9 This is a schematic diagram of the negative electrode tab on the negative electrode plate in one embodiment.

[0037] Figure 10 This is a schematic diagram of the negative electrode tab on the negative electrode plate in another embodiment.

[0038] Figure 11 This is a schematic diagram showing the connection between a portion of the electrode assembly and the cover plate assembly in one embodiment.

[0039] Figure 12 This is a schematic diagram of a portion of the electrode assembly in one embodiment.

[0040] Label Explanation:

[0041] 10. Housing; 11. Cover assembly; 12. First electrode post; 13. Second electrode post; 14. Explosion-proof valve; 15. Injection port; 20. Electrode assembly; 100. Electrode sheet; 101. Coated area; 102. Uncoated area; 103. Primer coating; 104. First insulating layer; 105. Second insulating layer; 106. Transition area; 110. Current collector; 120. Active material layer; 130. First insulating part; 140. Second insulating part; 150. Tab; 160, Current collector body; 200, Negative electrode sheet; 210, Negative electrode current collector; 220, Negative electrode active material layer; 230, Negative electrode tab area; 240, Negative electrode tab; 241, Connection area; 1112, Adapter piece; 1113, First electrode tab welding part; 1114, Second electrode tab welding part; 30, First adhesive tape; 31, First adhesive area; 32, Non-adhesive area; 33, Second adhesive area; 300, Diaphragm; 40, Second adhesive tape. Detailed Implementation

[0042] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0043] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the implementation conditions of this solution. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effectiveness and purpose achieved by this solution, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms used in this specification such as "upper," "lower," "left," "right," "middle," "below," "below," "first," "second," and "one," etc., are merely for clarity of description and are not intended to limit the scope of implementation of this solution. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the implementation of this solution.

[0044] The technical solution of this utility model will be further described in detail below with reference to the embodiments and accompanying drawings. 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 skilled in the art without creative effort are within the protection scope of this utility model.

[0045] This application provides an electronic device including at least one battery for providing electrical energy. The electronic device can be a vehicle, mobile phone, portable device, laptop, ship, spacecraft, electric toy, or power tool, etc. In one embodiment of this invention, the vehicle is, for example, a new energy vehicle, which can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. The spacecraft includes airplanes, rockets, space shuttles, and spacecraft, etc. The electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. The 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.

[0046] This application also provides a battery that can be used in the aforementioned electronic device. The battery includes a casing and an electrode assembly disposed within the casing. The electrode assembly includes positive and negative electrode plates and a separator. This invention does not limit the type and shape of the battery. The battery can be, for example, a primary battery or a secondary battery. A secondary battery can be, for example, a pouch battery, a cylindrical battery, or a prismatic battery, or, for example, a sodium-ion secondary battery or a lithium-ion secondary battery. In this embodiment, a lithium-ion secondary battery will be used as an example for illustration.

[0047] Please see Figures 1 to 2As shown, this application also provides an electrode sheet that can be used in the aforementioned battery. In one embodiment of this application, the electrode sheet 100 includes a current collector 110, which includes a coated area 101 and an uncoated area 102. The coated area 101 includes an active material layer 120, a first insulating portion 130, and a second insulating portion 140, which are sequentially arranged adjacent to each other along at least one side in the thickness direction of the current collector along a predetermined direction Y. In the thickness direction of the current collector 110, the thickness of the first insulating portion 130 is greater than the thickness of the second insulating portion 140. Adjacent means that the components are in direct contact or arranged according to a predetermined spacing, wherein the predetermined spacing ranges from 0.1 mm to 1 mm. In this embodiment, the first insulating portion 130 and the second insulating portion 140 are adjacent to each other, and the active material layer 120 and the first insulating portion 130 can be arranged at intervals. In other embodiments, the first insulating portion 130 may also partially overlap with the active material layer 120, that is, the first insulating portion 130 covers a portion of the thinned area of ​​the active material layer 120. The first insulating portion 130 includes a first insulating layer 104 and a second insulating layer 105 coated on the first insulating layer 104. The preset direction Y is, for example, the direction from the coated area 101 to the uncoated area 102. Compared to providing a single insulating layer, to improve the support at the interface between the active material layer and the insulating layer, when the insulating layer is thick, tearing of the uncoated area is easily caused during winding or stacking, or bending during coiling. When the insulating layer is thin, it cannot provide sufficient support for the uncoated area, leading to problems such as edge curling and wrinkling. In this application, by providing a first insulating portion and a second insulating portion with a thickness difference between the active material layer and the uncoated area, the first insulating portion between the active material layer and the second insulating portion can support the uncoated area. When the electrode sheet is used to assemble bare cells for coiling, the thickness transition from the first insulating portion to the second insulating portion disperses stress, reducing wrinkles at the interface between the uncoated area and the second insulating portion, or reducing edge curling of the uncoated area.

[0048] Please see Figure 1 and Figure 2As shown, in one embodiment of this utility model, the electrode 100 further includes an electrode tab 150, which protrudes from the current collector body 160 along a predetermined direction. The current collector body 160 includes an area covered by an active material layer 120 and a transition region 106 located between the active material layer 120 and the electrode tab. The transition region 106 extends from one end of the current collector 110 to the other end along a vertical direction X perpendicular to the predetermined direction. A second insulating portion 140 and a portion of a first insulating portion 130 are located on the surface of the electrode tab 150, and another portion of the first insulating portion 130 is located in the transition region 106. At this time, the height of the electrode tab includes the dimensions of the second insulating portion 140 and the portion of the first insulating portion 130 located on the electrode tab 150. In the thickness direction of the current collector 110, the orthographic projection of the first insulating portion 130 covers the radius (R-angle) of the electrode tab 150, that is, the beginning and end positions of the radius (R-angle) are all within the first insulating portion 130. By ensuring that the orthographic projection of the first insulating part covers the radius (R) of the tab, and by having the first and second insulating parts work together to reduce wrinkles at the junction of the uncoated area and the second insulating part, or to reduce folding of the uncoated area, the thickness at the base of the tab is greater during die-cutting. This reduces the generation of die-cutting burrs, and the radius (R) is completely located at the first insulating part. This avoids stress concentration points in the radius (R) area of ​​the tab due to thickness gradient differences, thus preventing cracking at the base of the tab due to stress concentration. At the same time, ensuring that the radius (R) area occupies a sufficiently wide portion of the first insulating part provides support for the tab, preventing it from folding or collapsing, and improving battery safety.

[0049] Please see Figure 1 and Figure 2 As shown, in one embodiment of this utility model, the radius R of the R-angle is, for example, 3mm-8mm. A larger R-angle allows for a larger reserved window during laser die-cutting, resulting in higher die-cutting quality. However, an excessively large R-angle leads to a larger R-angle area, increasing cost and reducing energy density. An excessively small R-angle results in insufficient support for the tab 150 after cutting, causing the tab 150 to fold or collapse. Furthermore, an excessively small R-angle also leads to excessive laser cutting variations, easily generating burrs. Therefore, controlling the R-angle within the above range allows for sufficient processing of the tab while reducing wrinkles and folds in the uncoated area and reducing die-cutting burrs. This reduces tab folding or collapse, improves tab quality, ensures die-cutting quality, reduces burrs, controls costs, and increases battery energy density.

[0050] Please see Figure 1 and Figure 3As shown, in one embodiment of this utility model, the width of the first insulating part 130 along the preset direction Y is W1mm, satisfying 0.3≤R / W1≤0.9. In one embodiment of this utility model, the value of W1 ranges from, for example, 1mm to 10mm. That is, the radius of the R-angle should be less than or equal to the width of the first insulating part 130, so that the R-angle area has a thicker insulating layer, thereby improving the cutting effect and isolating burrs. It can also ensure that the R-angle does not cross the first insulating part 130 and the second insulating part 140, reducing burrs and avoiding stress concentration points caused by thickness gradient differences in the R-angle area, thereby preventing the root of the electrode tab 150 from cracking due to stress concentration. At the same time, it is ensured that R / W1≥0.3 to ensure that the R-angle area occupies a sufficiently wide first insulating part 130, thereby supporting the electrode tab and preventing the electrode tab from folding or collapsing.

[0051] Please see Figures 1 to 3 As shown, in one embodiment of this utility model, along the preset direction Y, the width of the first insulating portion 130 is W1mm, and the width of the uncoated area 102 is W3mm, satisfying 1.5≤W3 / W1≤10. In a specific embodiment of this utility model, the value of W3 ranges from, for example, 9mm to 36mm. Since the thickness of the first insulating portion 130 is greater than the thickness of the second insulating portion 140, by controlling the minimum width of the first insulating portion 130, it is ensured that the laser cutting stop area falls on the first insulating portion 130. The thicker first insulating portion 130 can reduce the generation of die-cutting burrs and improve battery safety. At the same time, controlling the maximum width of the first insulating portion 130 can avoid wasting space in the coating area, thereby avoiding a reduction in the volumetric energy density of the battery cell. By controlling the width ratio of the uncoated area to the first insulating part, the uncoated area can be effectively supported and wrinkles and folds can be reduced. This avoids the waste caused by an excessively large uncoated area, and also avoids the limited welding area that would affect the assembly of the uncoated area when welding it to other structures in the battery, which would be caused by an excessively small uncoated area. This ensures that the welding area is large enough to ensure the transmission of current.

[0052] Please see Figures 1 to 3As shown, in one embodiment of this utility model, the width of the second insulating portion 140 along the preset direction Y is W2mm, satisfying 1.6≤W3 / W2≤25. In a specific embodiment of this utility model, the value of W2 ranges from, for example, 1mm to 15mm. By controlling the width ratio of the uncoated area 102 and the second insulating portion 140, it is ensured that the second insulating portion 140 can provide sufficient support and a transition area, further improving the strength of the uncoated area 102 of the current collector, further reducing wrinkles, collapsed edges, etc. at the junction of the uncoated area 102 or the second insulating portion 140 and the uncoated area 102, and reducing the flanging and folding of the uncoated area. At the same time, it can extend the length of the uncoated area and the first insulating portion, making it easier to match cells with more tabs.

[0053] Please see Figures 1 to 3 As shown, in one embodiment of the present invention, the first insulating part 130 includes a first insulating layer 104 and a second insulating layer 105 arranged sequentially along the thickness direction of the electrode sheet. The second insulating part 140 and the first insulating layer 104 are obtained by coating the same slurry once. That is, the first insulating layer 104 not covered by the second insulating layer 105 is defined as the second insulating part 140. The thickness, composition and other properties of the second insulating part 140 are the same as those of the first insulating layer 104.

[0054] Please see Figures 1 to 2 As shown, in one embodiment of this invention, a tab 150 is obtained by die-cutting the uncoated area 102, the second insulating portion 140, and a portion of the first insulating portion 130. The die-cutting stop position is designated as shoulder B of the tab 150, and the tab 150 extends from shoulder B to the side of the uncoated area 102 away from the active material layer 120. By stopping the die-cutting at the first insulating portion 130, within the overlap area of ​​the first insulating layer 104 and the second insulating layer 105, the insulation portion at the die-cutting stop position has a larger thickness, which reduces burrs and improves safety performance. During die-cutting, as the cutting speed increases, the thicker first insulating portion 130 can avoid burrs, and the overlap area of ​​the upper and lower insulating layers provides a certain thickness benefit, improving the performance of the electrode and thus enhancing the safety performance of the battery including the electrode.

[0055] See Figure 1 and Figure 3As shown, in one embodiment of this utility model, the width of the transition region 106 along the preset direction Y is d mm, satisfying 0.1≤d / W1≤0.7. That is, by controlling the relationship between the width of the transition region 106 and the width of the first insulating part 130, it is ensured that the first insulating part 130 is wide enough to cover the R-angle, ensuring that the R-angle does not cross the first insulating part 130 and the second insulating part 140, avoiding uneven stress due to uneven thickness, thereby preventing cracking at the root of the tab 150. At the same time, it is ensured that the laser die-cutting position corresponds to the overlapping position of the first insulating layer 104 and the second insulating layer 105, that is, in the thickness direction of the current collector 110, the overlapping range of the orthographic projection of the first insulating layer 104 and the second insulating layer 105 covers the side of the transition region 106 away from the active material layer 120. It can ensure that the insulating layer at the die-cutting stop position has sufficient thickness while supporting the tab and preventing the tab from flipping or collapsing, thereby improving the die-cutting burr problem.

[0056] See Figure 1 and Figure 3 As shown, in one embodiment of this invention, along a preset direction Y, the total width of the second insulating portion 140 and a portion of the first insulating portion 130 on the tab 150 is D mm, where D ranges from, for example, 4 mm to 24 mm. Controlling D ≥ 4 mm serves to support and isolate burrs, while controlling D ≤ 24 mm prevents the insulating portion on the tab 150 from excessively encroaching on the tab space, thus reducing the volumetric energy density of the battery cell. Therefore, by controlling the width of the insulating portion on the tab 150, the volumetric energy density of the battery cell can be ensured while satisfying the requirements of supporting the tab and avoiding burrs.

[0057] Please see Figures 1 to 3 As shown, in one embodiment of this invention, the thickness of the first insulating portion 130 in the thickness direction of the current collector 110 is 10μm-100μm. If the thickness of the first insulating portion 130 is too small, burrs are easily generated after die-cutting, and the excessively thin thickness is not conducive to burr isolation, which is detrimental to improving the safety performance of the battery. If the thickness of the first insulating portion 130 is too large, it may exceed the thickness of the active material layer 120, leading to rolled-up edges and a decrease in charge-discharge and cycle performance. Therefore, controlling the thickness of the first insulating portion 130 can reduce burrs and improve the cycle performance of the battery.

[0058] Please see Figures 1 to 3 As shown, in one embodiment of this utility model, the thickness of the second insulating portion 140 in the thickness direction of the current collector 110 is, for example, 0.5μm-9μm. If the thickness of the second insulating portion 140 is too small, it cannot play the role of insulation and support for the electrode tab. If the thickness of the second insulating portion 140 is too large, it will affect the bending of the electrode tab. In addition, excessive thickness will also cause the current collector to roll up the edge, which is not conducive to the winding of the current collector.

[0059] Please see Figures 1 to 3 As shown in one embodiment of this invention, in the electrode sheet 100, there is a thickness gradient between the uncoated area 102, the second insulating portion 140, and the first insulating portion 130. During the subsequent tab bending process, the bending deflection of these three areas is different. By adjusting the ratio of W1, W2, and W3, the bending point and bending curve shape of the tab can be controlled. This reduces problems such as tab folding or tearing during the coiling and welding after the electrode sheet is wound or stacked, and avoids tab insertion problems.

[0060] Please see Figure 1 and Figure 4 As shown, in one embodiment of this utility model, a base coating layer 103 is further provided between the active material layer 120 and the current collector 110. Along a predetermined direction Y, one end of the base coating layer 103 extends beyond the active material layer 120, wherein the width of the base coating layer 103 extending beyond the active material layer 120 is, for example, W4 mm. In a specific embodiment of this utility model, the value of W4 ranges from, for example, 0.1 mm to 2 mm. The base coating layer 103 is, for example, a carbon coating layer. Extending the base coating layer 103 beyond the active material layer 120 prevents direct contact between the active material layer 120 and the current collector 110, thereby increasing the adhesion between the active material layer 120 and the current collector 110 and reducing the shedding of the active material layer 120. This can enhance the conductivity between the active material layer 120 and the current collector 110 while reducing folds and wrinkles in the uncoated area and ensuring the welding area.

[0061] Please see Figure 1 and Figure 4 As shown, in one embodiment of this utility model, the base coating 103 and the first insulating layer 104 are spaced apart. A preset distance G mm exists between the first insulating layer 104 and the base coating 103. In a specific embodiment of this utility model, the value of G ranges from, for example, 0.5 mm to 4 mm. By setting the preset distance G, mutual dissolution caused by direct contact between the first insulating layer 104 and the base coating 103 can be avoided. Simultaneously, the second insulating layer 105 at the preset distance G is slightly thinner than other positions (not shown in the figure), preventing interpenetration between the second insulating layer 105 and the active material layer 120. By setting the first insulating layer 104 and the second insulating layer 105, it is possible to ensure the formation of a first insulating portion and a second insulating portion with a thickness difference, ensuring a smooth transition in thickness from the first insulating portion to the second insulating portion. This disperses stress, reduces wrinkles at the junction of the uncoated area and the second insulating portion, reduces folding in the uncoated area, reduces tab insertion, and prevents the first insulating layer from shedding material, while also reducing burrs and bulging issues.

[0062] Please see Figures 3 to 4As shown, in one embodiment of this utility model, the current collector 110 is, for example, a positive current collector, and the current collector 110 is, for example, an aluminum foil, and the thickness of the current collector 110 is, for example, 5μm-20μm, or further, 10μm-15μm. The active material layer 120, the first insulating portion 130, and the second insulating portion 140 are disposed on one side surface of the current collector, or simultaneously disposed on both sides of the current collector 110.

[0063] Please see Figures 3 to 4 As shown, in one embodiment of this utility model, the first insulating layer 104 includes, for example, a first adhesive and an inorganic insulating material. The first adhesive is, for example, an aqueous adhesive, and further includes at least one of the following: polyacrylic acid (PAA), styrene-butadiene rubber (SBR), polyvinyl alcohol (PVA), polyacrylamide (PAM), methylcellulose and its salts, chitosan and its salts, alginate and its salts, etc. The inorganic insulating material includes, for example, at least one of boehmite, alumina, titanium dioxide, zirconium dioxide, zinc oxide, barium sulfate, boron nitride, aluminum nitride, or magnesium nitride, etc. In one embodiment of this utility model, the mass ratio of the first adhesive to the inorganic insulating material is, for example, 8-30:70-92.

[0064] Please see Figures 3 to 4As shown, in one embodiment of this invention, the second insulating layer 105 includes, for example, a second adhesive and an inorganic insulating material. The second adhesive is, for example, an oil-based adhesive, and may include at least one of polyvinylidene fluoride or oil-based polyimide (PI), wherein the oil-based polyimide includes, for example, at least one of pyromellitic polyimide or biphenyl / ether anhydride polyimide. The inorganic insulating material includes, for example, at least one of boehmite, alumina, titanium dioxide, zirconium dioxide, zinc oxide, barium sulfate, boron nitride, aluminum nitride, or magnesium nitride. In one embodiment of this invention, the mass ratio of the second adhesive to the inorganic insulating material is, for example, 8-30:70-92. In this embodiment, the median particle size Dv50 of the inorganic insulating material in the second insulating layer 105 is greater than that in the first insulating layer 104. This ensures the formation of a thinner first insulating layer 104 during the preparation process and improves the support of the second insulating layer 105. The median particle size Dv50 refers to the particle size value corresponding to a cumulative distribution of 50% in the particle size distribution curve. The insulating layer obtained through the inorganic insulating material and binder improves the support effect and insulation of the insulating portion. The second binder is selected from oil-based binders, and through complementary properties, it significantly improves the overall performance of the insulating portion. Furthermore, the second binder improves the flexibility, adhesion, electrolyte resistance, high insulation, and heat resistance of the second insulating layer 105, and does not react within the lithium battery charge / discharge voltage range, thus not affecting battery performance.

[0065] Please see Figures 3 to 4 As shown, in one embodiment of this invention, the active material layer 120 includes an active material, a conductive agent, and a third binder. The active material includes, for example, a lithium phosphate material, or at least one selected from lithium iron phosphate (LiFePO4) or lithium manganese iron phosphate. The conductive agent is selected from, for example, one selected from conductive carbon black, acetylene black, nano-metal powder, graphene, carbon nanotubes, or carbon nanofibers, or a combination of two or more mixed in any proportion. The third binder is selected from one or more mixtures of polyvinylidene fluoride (PVDF), oily polyimide, polyvinylidene fluoride-hexafluoropropylene, or polytetrafluoroethylene. In one embodiment of this invention, the mass ratio of the active material, conductive agent, and third binder is, for example, 90-98:1-5:1-5. This invention does not limit the thickness of the active material layer 120 on the current collector side; the thickness is selected based on battery design requirements. In this embodiment, the thickness of the active material layer 120 on the current collector side is, for example, greater than or equal to the thickness of the first insulating portion 130 on the current collector side.

[0066] Please see Figures 3 to 4As shown, in one embodiment of this invention, the base coating 103 includes, for example, a carbon material, a fourth binder, and a neutralizing agent. The carbon material includes at least one of conductive carbon black, graphite, graphene, or carbon nanotubes. The fourth binder includes at least one of polyacrylic acid, styrene-butadiene rubber, polyvinyl alcohol, polyacrylamide, methylcellulose and its salts, chitosan and its salts, alginate and its salts. The neutralizing agent includes at least one of lithium hydroxide, sodium hydroxide, calcium hydroxide, or ammonia. The thickness of the base coating 103 is, for example, 0.1 μm-2 μm. Controlling the thickness of the base coating 103 improves conductivity while reducing its impact on energy density. In one embodiment of this invention, the mass ratio of the carbon material, the fourth binder, and the neutralizing agent is, for example, 40-53:45-55:2-5.

[0067] Please see Figures 3 to 4 As shown, in one embodiment of this invention, when forming the base coating 103 and the first insulating layer 104, a first binder and an inorganic insulating material are dispersed in a first solvent at a mass ratio to obtain a first slurry. Carbon material, a fourth binder, and a neutralizing agent are dispersed in a second solvent at a mass ratio to obtain a carbon slurry. The first and second solvents include, for example, aqueous solvents such as deionized water or high-purity water. During the coating process, the first slurry and the carbon slurry are simultaneously formed on at least one side of the current collector 110 using gravure coating at a preset spacing, and then dried to obtain the first insulating layer 104 and the base coating 103. The first insulating layer 104 and the base coating 103 can also be customized at the current collector supplier stage according to usage requirements. Both the first and fourth binders are aqueous binders, which have high compatibility with the gravure coating process during preparation, low cost, and do not require organic gas recovery, simplifying the production line.

[0068] Please see Figures 3 to 4 As shown, in one embodiment of this invention, when forming the second insulating layer 105 and the active material layer 120, the second binder and inorganic insulating material are dispersed in a third solvent to obtain a second slurry, and the active material, the third binder, and the conductive agent are dispersed in a fourth solvent to obtain an active slurry. The third and fourth solvents include, for example, organic solvents such as N-methylpyrrolidone (NMP). During the coating process, the second slurry and the active slurry are simultaneously coated onto portions of the first insulating layer 104 and the base layer 103 using methods such as roller coating, spraying, or slot coating, and then dried to obtain the second insulating layer 105 and the active material layer 120.

[0069] Please see Figures 5 to 7As shown, in one embodiment of this utility model, the battery further includes a housing 10 with an upper opening, an electrode assembly disposed within the housing 10, and a cover plate assembly 11 that closes the upper opening. The tabs of the electrode assembly 20 are electrically connected to the terminals on the housing 10. The shape of the housing 10 matches the shape of the electrode assembly 20, and the material of the housing 10 is, for example, an aluminum shell, a steel shell, or a flexible shell. The housing 10 is a receiving cavity with an upper opening for accommodating the electrode assembly 20. Specifically, after the electrode assembly 20 is placed in the housing 10 through the upper opening, the housing 10 is sealed using the cover plate assembly 11. The cover plate assembly 11 is provided with a first terminal 12, a second terminal 13, an explosion-proof valve 14, and an injection hole 15, etc. Electrolyte is injected through the injection hole 15, and then the injection hole 15 is sealed. In this embodiment, the first electrode 12 and the second electrode 13 have opposite polarities, and are either positive or negative electrodes, respectively. This invention does not limit the specific polarity category of the first electrode 12 and the second electrode 13. The first electrode 12 is electrically connected to a tab of the same polarity on the electrode assembly 20, and the second electrode 13 is also electrically connected to a tab of the same polarity on the electrode assembly 20. In this embodiment, the positions of the first electrode 12 and the second electrode 13 are not limited; they can be located at the same end of the housing or at both ends of the housing, depending on the position of the tabs on the electrode assembly 20 or the design requirements.

[0070] Please see Figure 5 As shown, in one embodiment of this utility model, when the first pole 12 and the second pole 13 are disposed at one end of the housing, the explosion-proof valve 14 and the injection port 15 are disposed between the first pole 12 and the second pole 13. The explosion-proof valve 14 is, for example, disposed at the middle position of the first pole 12 and the second pole 13, and is respectively at a preset distance from the first pole 12 and the second pole 13. The injection port 15 is disposed between the explosion-proof valve 14 and the first pole 12, or between the explosion-proof valve 14 and the second pole 13. That is, the explosion-proof valve 14, the injection port 15, the first pole 12, and the second pole 13 are arranged alternately. The explosion-proof valve 14 can open its venting function when the battery cell is working normally, allowing airflow inside and outside the battery cell to pass through while preventing the passage of particulate matter. When thermal runaway occurs in the battery cell, and the pressure difference inside and outside the battery cell reaches the preset explosion-proof value, the explosion-proof valve opens, allowing both gas and solids to be discharged from the inside of the battery cell to the outside through the explosion-proof valve, thus improving the safety performance of the battery cell.

[0071] Please see Figures 6 to 7As shown, in one embodiment of this utility model, the electrode assembly 20 includes a positive electrode sheet and a negative electrode sheet 200, and a separator 300. The positive electrode sheet is selected from the aforementioned electrode sheet 100. The separator 300 is disposed between the positive electrode sheet and the negative electrode sheet 200 to prevent contact between the positive electrode sheet and the negative electrode sheet 200, which could lead to safety issues. An electrolyte (not shown in the figure) is filled between the positive electrode sheet, the negative electrode sheet 200, and the separator 300, as well as between the electrode assembly 20 and the housing, to conduct ions between the positive and negative electrode sheets. The electrolyte can be any suitable lithium-ion battery electrolyte. This application does not specifically limit the stacking method of the positive and negative electrode sheets; the specific method is selected according to the manufacturing requirements.

[0072] In one embodiment of this invention, the electrolyte includes, for example, an organic solvent and a lithium salt. The organic solvent is selected from one or more of ethylene carbonate (EC), propylene carbonate (PC), ethyl acetate (EA), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), or diethyl carbonate (DEC). The lithium salt is selected from, for example, one or more of lithium bis(fluorosulfonyl)imide (LiFSi), lithium difluorophosphate (LiPO2F2), lithium hexafluorophosphate (LiPF6), or lithium tetrafluoroborate (LiBF4). In one embodiment of this invention, the lithium salt is selected from, for example, lithium hexafluorophosphate, and the organic solvent is selected from, for example, a mixture of ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, and propylene carbonate. Ethylene carbonate, methyl ethyl carbonate, diethyl carbonate, and propylene carbonate are mixed, for example, in a volume ratio of 1:1:1:1. The thoroughly dried LiPF6 is dissolved in the mixed organic solvent in an argon-atmosphere glove box with a water content of less than 10 ppm. After thorough mixing, an electrolyte is obtained, wherein the concentration of LiPF6 is, for example, 1 mol / L.

[0073] Please see Figures 6 to 7As shown, in one embodiment of this utility model, the electrode 100, the negative electrode 200, and the separator are formed into an electrode assembly 20 by means of winding or stacking, for example, the stacking can be, for example, a multilayer stack or a Z-shaped stack, etc., and this application does not impose specific limitations. The separator 300 is, for example, a polyethylene film (PE), a polypropylene film (PP), a glass fiber film, a polyethylene film, or a composite film, etc., and in this application, the thickness of the separator 300 is not limited, as long as it meets the usage requirements.

[0074] Please see Figure 8 As shown, in one embodiment of this utility model, the negative electrode 200 includes a negative electrode current collector 210 and a negative electrode active material layer 220 coated on at least one surface of the negative electrode current collector 210. That is, the negative electrode current collector 210 has two surfaces opposite each other in its thickness direction, and the negative electrode active material layer 220 can be disposed on either or both of the two surfaces in the thickness direction of the negative electrode current collector 210. The negative electrode current collector 210 can be a copper foil current collector, with a thickness of, for example, 5 μm-20 μm. The negative electrode current collector 210 can also be a composite current collector, which includes a polymer matrix and copper layers located on the upper and lower surfaces of the polymer matrix. The polymer matrix can be selected from polyethylene terephthalate, polypropylene, polyimide, polystyrene, or polyamide, etc.

[0075] Please see Figure 8 As shown, in one embodiment of this utility model, on the negative electrode current collector 210, the area coated with the negative electrode active material layer 220 is defined as the electrode area, and the area of ​​the negative electrode current collector 210 without the negative electrode active material layer 220 is defined as the negative electrode tab area 230, used to form the negative electrode tab. The electrode area and the negative electrode tab area 230 are arranged adjacent to each other. The negative electrode active material layer 220 includes, for example, a negative electrode active material, a negative electrode binder, a thickener, and a negative electrode conductive agent. The negative electrode active material is selected from, for example, any one or a combination of at least two of soft carbon, hard carbon, artificial graphite, silicon, silicon oxide, silicon carbide, or lithium titanate. The negative electrode binder is selected from, for example, any one or more of polypropylene, polyacrylic acid and its derivatives, or styrene-butadiene rubber. The negative electrode conductive agent is selected from, for example, any one or more of conductive carbon black, acetylene black, carbon nanotubes, and graphene. The thickener is selected from, for example, sodium carboxymethyl cellulose. This application does not limit the mass ratio of the negative electrode active material, negative electrode binder, thickener, and negative electrode conductive agent, and the selection is made according to the preparation requirements. In one embodiment of this application, the mass ratio of the negative electrode active material, negative electrode binder, thickener and negative electrode conductive agent is, for example, 90-97:1-5:1-2:1-3.

[0076] Please see Figure 9 and Figure 10As shown, in one embodiment of this utility model, the negative electrode sheet 200 includes a plurality of negative electrode tabs 240, and a portion of the negative electrode active material layer 220 covers at least a portion of the surface of the negative electrode tabs 240; or a connection region 241 is provided between the negative electrode tabs 240 and the negative electrode active material layer 220, and the connection region 241 is continuously provided within the negative electrode tab region 230, that is, the negative electrode active material layer 220 is not provided on the connection region 241, and the negative electrode active material layer 220 does not cover the negative electrode tabs 240.

[0077] Please see Figure 2 , Figures 10 to 12 As shown, in one embodiment of this utility model, the electrode 100, negative electrode 200, and diaphragm 300 are formed into an electrode assembly 20 by means of winding or stacking, for example. The electrode assembly 20 includes a main body 1 and an electrode tab 150 and a negative electrode tab 240 located at one end of the main body 1. The electrode tab 150 is a positive electrode tab. The main body 1 is formed by laminating the shoulder B of the electrode tab. The two electrode assemblies 20 are disposed opposite to each other in the housing 10. Each set of electrode assemblies 20 has an electrode tab 150 and a negative electrode tab 240 at the end facing the cover plate assembly 11. The electrode tab 150 and the negative electrode tab 240 are bent and fixedly connected to the adapter piece 1112 of the cover plate assembly 11. The cover plate assembly 11 has two sets of adapter pieces 1112, which are respectively connected to the positive electrode tab and the negative electrode tab. The adapter piece 1112 has a width direction W including a first tab welding portion 1113 and a second tab welding portion 1114 symmetrically arranged along the length direction W of the adapter piece 1112. There are two sets of electrode assemblies 20. The tabs 150 of one set of electrode assemblies 20 and the tabs 150 of the other set of electrode assemblies 20 are bent relative to each other and then welded to the first tab welding portion 1113 and the second tab welding portion 1114 of one adapter piece 1112, respectively. The negative tabs 240 of one set of electrode assemblies 20 and the negative tabs 240 of the other set of electrode assemblies 20 are bent relative to each other and then welded to the first tab welding portion 1113 and the second tab welding portion 1114 of the other adapter piece 1112, respectively. The two sets of electrode assemblies 20 are then bent relative to each other and installed into the housing 10.

[0078] Please see Figure 4 , Figures 10 to 12As shown, in one embodiment of this utility model, the tab 150 includes an uncoated area 102, a second insulating portion 140 disposed on one side of the tab 150 in the same thickness direction, and a portion of a first insulating portion 130. The uncoated area 102 is fixedly connected to the welding portion of the adapter piece 1112, and the second insulating portion 140 and at least a portion of the first insulating portion 130 are connected between the main body 1 and the uncoated area 102. The combined thickness of the first insulating portion 130 and the second insulating portion 140 provides good support, and when the tab 150 is bent and welded to the tab welding portion, the bending of the tab 150 is not affected, reducing problems such as tab folding. A first adhesive tape 30 is provided on the side of the tab 150 facing away from the cover plate assembly 11 to protect the tab 150. The first adhesive tape 30 includes a first adhesive area 31, a second adhesive area 33, and a non-adhesive area 32 located between the first adhesive area 31 and the second adhesive area 33. The first adhesive area 31 covers the main body 1, and the second adhesive area 33 covers the uncoated area 102. In the thickness direction of the electrode assembly, the orthogonal projections of the first insulating portion 130 and the second insulating portion 140 are completely located within the non-adhesive area 32, thereby preventing the insulating portion from falling off when the tab is static or during tab assembly. A second adhesive tape 40 is provided on the negative electrode tab 240 facing away from the cover plate assembly 11 to protect the negative electrode tab 240. The tape improves the safety of the foil leakage, and the non-adhesive area covers the insulating portion to prevent the insulating portion from falling off. The tape provides support and can prevent the tab from being inserted into or torn.

[0079] The present invention will be explained in more detail below by referring to embodiments, which should not be construed as limiting. Appropriate modifications may be made within the scope of the present invention, and all such modifications shall fall within the technical scope of the present invention.

[0080] Example 1

[0081] Preparation of the electrode sheet: Polyacrylic acid and boehmite were dispersed in deionized water at a mass ratio of 12:88 to obtain the first slurry. Conductive carbon black, polyacrylic acid, and calcium hydroxide were dispersed in deionized water at a mass ratio of 45:52:3 to obtain the carbon slurry. Polyvinylidene fluoride and boehmite were dispersed in NMP at a mass ratio of 97:2 to obtain the second slurry. LiFePO4, polyvinylidene fluoride, and acetylene black were dispersed in NMP at a mass ratio of 97:2:1 to obtain the active slurry.

[0082] The first slurry and carbon slurry are simultaneously and alternately formed on one side of the current collector using a gravure coating process, and then dried to obtain the first insulating layer and the base coating layer. The second slurry and the active slurry are simultaneously coated onto a portion of the first insulating layer and the base coating layer using a roller coating process, and then dried to obtain the second insulating layer and the active material layer. The positive electrode sheet is then obtained through cold pressing, slitting, die-cutting, and sheet cutting processes.

[0083] In the positive electrode sheet, along a predetermined direction, the width W1 of the first insulating portion is 10 mm, the radius of the R-angle is 6 mm, the width W2 of the second insulating portion is 5 mm, the width d of the transition region is 8 mm, and the total width D of the insulating portions on the tab is 9 mm. The width W3 of the uncoated area is 15 mm, the thickness of the first insulating portion is 30 μm, the thickness of the second insulating portion is 5 μm, one end of the undercoating layer extends 0.2 mm beyond the active material layer, the thickness of the undercoating layer is 1 μm, and the predetermined spacing G between the first insulating layer and the undercoating layer is 0.5 mm.

[0084] Preparation of the negative electrode sheet: Artificial graphite, conductive carbon black, sodium carboxymethyl cellulose, and styrene-butadiene rubber were mixed in a mass ratio of 96:1:1:2, deionized water was added, and the mixture was stirred evenly under vacuum to obtain a negative electrode slurry. The negative electrode slurry was coated onto a 6μm thick copper foil, transferred to an oven for drying, and then subjected to rolling, slitting, die-cutting, and sheet cutting processes to obtain the negative electrode sheet.

[0085] Preparation of electrolyte: Ethylene carbonate, methyl ethyl carbonate, diethyl carbonate and propylene carbonate are mixed in a volume ratio of 1:1:1:1. In an argon atmosphere glove box with a water content of less than 10 ppm, fully dried LiPF6 is dissolved in the mixed organic solvent and mixed evenly to obtain the electrolyte. The concentration of LiPF6 is, for example, 1 mol / L.

[0086] Selection of diaphragm: 9μm thick polyethylene was used as the diaphragm.

[0087] Battery fabrication: The positive electrode, separator, and negative electrode are stacked sequentially and wound, with the separator positioned between the positive and negative electrodes to act as a separator. Except for the innermost and outermost rings, each ring of the negative electrode has a tab, resulting in a wound bare cell. The bare cell is then placed in an aluminum casing, a top cover assembly is assembled, electrolyte is injected, and the casing is sealed to obtain a lithium-ion battery.

[0088] Example 2

[0089] In the positive electrode sheet, along the preset direction, the width W1 of the first insulating part is 10mm, the radius of the R angle is 8mm, and the rest of the operation is the same as in Example 1.

[0090] Example 3

[0091] In the positive electrode sheet, along the preset direction, the width W1 of the first insulating part is 10mm, the radius of the R angle is 3mm, and the rest of the operation is the same as in Example 1.

[0092] Example 4

[0093] In the positive electrode sheet, along the preset direction, the width W1 of the first insulating part is 20mm, the radius of the R angle is 6mm, and the rest of the operation is the same as in Example 1.

[0094] Example 5

[0095] In the positive electrode sheet, along the preset direction, the width W1 of the first insulating part is 12mm, the radius of the R angle is 6mm, and the rest of the operation is the same as in Example 1.

[0096] Example 6

[0097] In the positive electrode, the width d of the transition region is 1 mm along a predetermined direction. The remaining operations are the same as in Example 1.

[0098] Example 7

[0099] In the positive electrode sheet, the width d of the transition zone is 7mm along the preset direction, and the rest of the operation is the same as in Example 1.

[0100] Example 8

[0101] In the positive electrode sheet, the width d of the transition zone is 5mm along a preset direction, and the rest of the operation is the same as in Example 1.

[0102] Example 9

[0103] In the positive electrode sheet, along the preset direction, the width W3 of the uncoated area is 36mm, the width W1 of the first insulating part is 6mm, and the rest of the operation is the same as in Example 1.

[0104] Example 10

[0105] In the positive electrode sheet, along the preset direction, the width W3 of the uncoated area is 60mm, the width W1 of the first insulating part is 6mm, and the rest of the operation is the same as in Example 1.

[0106] Example 11

[0107] In the positive electrode sheet, along the preset direction, the width W3 of the uncoated area is 0 mm, the width W1 of the first insulating part is 6 mm, and the rest of the operation is the same as in Example 1.

[0108] Example 12

[0109] In the positive electrode sheet, along the preset direction, the width W3 of the uncoated area is 72mm, the width W1 of the first insulating part is 6mm, and the rest of the operation is the same as in Example 1.

[0110] Example 13

[0111] In the positive electrode sheet, along the preset direction, the width W3 of the uncoated area is 25mm, the width W2 of the second insulating part is 1mm, and the rest of the operation is the same as in Example 1.

[0112] Example 14

[0113] In the positive electrode sheet, along the preset direction, the width W3 of the uncoated area is 25mm, the width W2 of the second insulating part is 15mm, and the rest of the operation is the same as in Example 1.

[0114] Example 15

[0115] In the positive electrode sheet, along the preset direction, the width W3 of the uncoated area is 25mm, the width W2 of the second insulating part is 20mm, and the rest of the operation is the same as in Example 1.

[0116] Example 16

[0117] In the positive electrode sheet, along the preset direction, the width W3 of the uncoated area is 28mm, the width W2 of the second insulating part is 0.8mm, and the rest of the operation is the same as in Example 1.

[0118] Comparative Example 1

[0119] In the positive electrode sheet, along a preset direction, the width W1 of the first insulating part is 30mm, the radius of the R angle is 6mm, and the rest of the operation is the same as in Example 1.

[0120] Comparative Example 2

[0121] In the positive electrode sheet, along the preset direction, the width W1 of the first insulating part is 6mm, the radius of the R angle is 6mm, and the rest of the operation is the same as in Example 1.

[0122] In one embodiment of this invention, to obtain the thickness of the first insulating layer and the second insulating layer on the current collector, a scanning electron microscope (SEM) is used to examine the electrode along its surface. Figure 1 The cross-section along the AA direction is scanned, and the maximum thickness of the first insulating part and the second insulating part is recorded as the thickness of the first insulating part and the second insulating part along the thickness direction of the current collector.

[0123] In one embodiment of this utility model, to obtain the tab wrinkling performance, after obtaining the bare cell, the distance from the side of each tab furthest from the active material layer to the active material layer is measured using a camera (if it is the design value after battery disassembly, for tabs of equal height, the maximum value of the width of the uncoated area, the first insulating part, and the second insulating part is used; if the tabs are of unequal height, the measurement is performed in the initial state first, then the tabs are stretched straight, and the maximum and minimum values ​​of each uncoated area are compared to determine the tab deviation value), and the average value of the difference is obtained, which is defined as the tab deviation value (if the deviation value of the uncoated area is obtained, the distance from the side of the uncoated area furthest from the active material layer to the side adjacent to the active material layer of each layer is obtained using a camera). The tab deviation value is used to characterize the tab wrinkling performance; the smaller the tab deviation value, the fewer the tabs wrinkle. In this application, the uncoated areas of the individual batteries in Examples 1-16 and Comparative Examples 1-2 are all set at the same height.

[0124] In one embodiment of this utility model, in order to obtain the tab folding situation, after obtaining the bare cell, the orthographic projection area of ​​each tab on the plane where the current collector is located is obtained by a CCD camera and denoted as S1. The orthographic projection area of ​​each tab on the plane where the current collector is located after being flattened is denoted as S2 (if the folding situation of the uncoated area is obtained, the orthographic projection area of ​​the uncoated area of ​​each layer on the plane where the current collector is located, and the orthographic projection area of ​​the uncoated area of ​​each layer on the plane where the current collector is located after being flattened are obtained by a CCD camera). The calculation error is (S2-S1) / S2×100%. Tabs with an error greater than 5% are defined as tabs that have folded. The ratio of the number of tabs that have folded to the total number of tabs is calculated.

[0125] In one embodiment of this utility model, during the coating process, after every 3000m of electrode sheet is completed, a comprehensive inspection is performed on the electrode sheet, and the frequency of tearing in the uncoated areas or on the tabs is counted. A tearing frequency of ≤1 / 1000 is considered acceptable; a frequency greater than 1 / 1000 may cause subsequent safety issues with the battery cell.

[0126] Table 1. Some characteristics and properties of the positive electrode sheets in Examples 1-5 and Comparative Examples 1-2

[0127]

[0128] Please refer to Table 1. Comparing Examples 1-5 and Comparative Examples 1-2, it can be seen that as the R-angle size and the R / W1 ratio of the first insulating portion width increase, the proportion of tab tearing first decreases and then increases, while the proportion of uncoated area folding increases. When the R / W1 ratio is too small, the R-angle area does not occupy a sufficiently wide first insulating portion, thus weakening the support of the tab and increasing the proportion of tab and uncoated area folding. When the R / W1 ratio is large, the R-angle area may span the first and second insulating portions. Due to the thickness gradient difference, stress concentration points are generated in the R-angle area, increasing the likelihood of tab root cracking due to stress concentration, and also increasing the proportion of uncoated area folding. Therefore, controlling the ratio of the R-angle size to the width of the first insulating portion within a set range can reduce tab tearing and reduce uncoated area folding and wrinkling, thereby improving battery safety.

[0129] Table 2. Some characteristics and performance of the positive electrode sheets in Examples 1 and 6-8

[0130]

[0131] Referring to Table 2, a comparison of Examples 1 and 6-8 shows that the tab tearing rate increases with the increase of the ratio of the transition zone width to the width of the first insulating portion (d / W1). This is because as the d / W1 ratio increases, the first insulating portion is not wide enough to cover the radius (R-angle), causing the R-angle to span across the first and second insulating portions. This uneven thickness leads to uneven stress, resulting in root cracking of the tab. Therefore, by controlling the relationship between the width of the transition zone and the width of the first insulating portion, a sufficiently wide first insulating portion can be ensured to cover the R-angle, reducing root cracking of the tab. Simultaneously, ensuring that the laser die-cutting position corresponds to the overlap of the first and second insulating layers, and ensuring that the insulating layer at the die-cutting stop position has sufficient thickness, improves the die-cutting burr problem.

[0132] Table 3. Some characteristics and performance of the positive electrode sheets in Examples 1 and 9-12.

[0133]

[0134] Please refer to Table 3. Comparing Examples 1, 9-10, and Example 12, it can be seen that when W3 / W1 meets the ratio of 1.5-10, the proportion of folds in the uncoated area is relatively small, indicating that wrinkles and folds in the uncoated area are less. Furthermore, in Example 10, the proportion of folds is slightly higher than in Example 9, but overall it is less than 0.5%. This is because the width of the uncoated area is larger, and the first insulating part cannot provide effective support, leading to increased defects such as folds and wrinkles in the uncoated area. In Example 11, when no uncoated area is provided, there is no weldable part for the tab, which does not meet the battery manufacturing requirements. When the width of the uncoated area is too large, the first insulating part cannot provide effective support, and the uncoated area is more prone to folds and wrinkles, increasing the proportion of folds. Additionally, an excessively large width of the uncoated area affects welding, resulting in failure to meet battery manufacturing requirements. Therefore, controlling the width ratio of the uncoated area to the width of the first insulating part within a set range, while simultaneously controlling the width of the uncoated area, reduces defects such as folds and wrinkles in the uncoated area, while meeting the battery manufacturing requirements.

[0135] Table 4. Some characteristics and performance of the negative electrode sheets in Examples 1, 13-16

[0136]

[0137] Please refer to Table 4. Comparing Examples 1 and 13-16, it can be seen that as the ratio of the width W3 / W2 of the uncoated area and the second insulating part increases, the tab deviation value first decreases and then increases, while the proportion of folding in the uncoated area increases. When the ratio of W3 / W2 is small, the proportion of tab folding is small, but the supporting effect of the second insulating part is weakened, which leads to an increase in defects such as wrinkles and folds in the uncoated area. When the ratio of W3 / W2 is large, the width of the second insulating part is small, and the transition from the first insulating part to the second insulating part is too small, resulting in the uncoated area being prone to folding and tab deviation. Therefore, controlling the ratio of the width of the uncoated area and the second insulating part within a set range can reduce defects such as folding and wrinkling in the uncoated area and improve battery safety.

[0138] In summary, the electrode sheet and the battery and electronic device including it provided by this utility model, by setting a first insulating part and a second insulating part with a thickness difference between the active material layer and the uncoated area, the first insulating part between the active material layer and the second insulating part can support the uncoated area. When the electrode sheet is used to assemble bare cells for bundling when there is a thickness difference between the first insulating part and the second insulating part, the thickness transition from the first insulating part to the second insulating part can disperse stress, reduce wrinkles at the junction of the uncoated area and the second insulating part, or reduce the folding of the uncoated area. At the same time, the orthographic projection of the first insulating part covers the R-corner of the electrode tab. During die-cutting, the thickness at the root of the electrode tab is larger, which can reduce the generation of die-cutting burrs. Moreover, the R-corner is completely located at the first insulating part, which can avoid stress concentration points in the R-corner area of ​​the electrode tab due to the thickness gradient difference, thereby avoiding cracking at the root of the electrode tab due to stress concentration. At the same time, it ensures that the R-corner area occupies a sufficiently wide first insulating part, thereby playing a role in supporting the electrode tab and preventing Folding or collapsing the tabs improves battery safety and prevents stress concentration points in the tab's radius (R-angle) area due to thickness gradient differences, thus avoiding cracking at the tab root caused by stress concentration. By controlling the width ratio of the uncoated area to the first insulation part, the uncoated area is effectively supported and wrinkled or folded, avoiding waste due to excessively large uncoated area. It also avoids the limited welding area that would affect the assembly of the uncoated area when welding it to other battery structures, ensuring sufficient welding area for current transmission. Furthermore, controlling the width ratio of the uncoated area to the first insulation part ensures that the laser-cut cutoff area falls on the first insulation part during die-cutting, reducing die-cutting burrs and improving battery safety. Finally, controlling the width ratio of the uncoated area to the second insulation part allows for extending the overall tab length while ensuring sufficient support, facilitating the matching of cells with more tabs.

[0139] The above description is only a preferred embodiment of this application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the utility model involved in this application is not limited to the technical solutions formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the concept of the utility model. For example, technical solutions formed by replacing the above features with technical features with similar functions disclosed in this application (but not limited to) each other.

[0140] Apart from the technical features described in the specification, the other technical features are known to those skilled in the art. To highlight the innovative features of this utility model, the other technical features will not be described in detail here.

Claims

1. An electrode sheet, characterized in that, include: A current collector, comprising a coated area and an uncoated area, wherein the coated area comprises an active material layer, a first insulating portion, and a second insulating portion disposed sequentially adjacent to each other on at least one side of the current collector along a predetermined direction in the thickness direction of the current collector; In the thickness direction of the current collector, the thickness of the first insulating portion is greater than the thickness of the second insulating portion, and the first insulating portion includes a first insulating layer and a second insulating layer coated on the first insulating layer; The electrode tab protrudes from the current collector body in the preset direction. The current collector body includes the active material layer covering area and a transition area located between the active material layer and the electrode tab. The transition area extends from one end of the current collector to the other end in a direction perpendicular to the preset direction. The second insulating portion and a portion of the first insulating portion are located on the surface of the electrode tab, and another portion of the first insulating portion is located in the transition area. In the thickness direction of the current collector, the orthographic projection of the first insulating portion covers the radius (R) of the electrode tab.

2. The electrode sheet according to claim 1, characterized in that, Along the preset direction, the width of the first insulating part is W1 mm, satisfying 0.3≤R / W1≤0.9; or, the radius R of the R angle is 3mm-8mm.

3. The electrode sheet according to claim 2, characterized in that, Along the preset direction, the width of the transition zone is dmm, satisfying 0.1≤d / W1≤0.7; or The value of W1 ranges from 1mm to 10mm.

4. The electrode sheet according to claim 1, characterized in that, Along the preset direction, the total width D of the second insulating portion and part of the first insulating portion on the electrode tab is 4mm-24mm.

5. The electrode sheet according to claim 1, characterized in that, The first insulating layer and the active material layer are spaced apart; Along the preset direction, the second insulating portion and the first insulating layer are obtained by applying the same slurry in one step.

6. The electrode sheet according to claim 5, characterized in that, In the thickness direction of the current collector, the overlapping range of the orthographic projections of the first insulating layer and the second insulating layer covers the transition region away from the side of the active material layer.

7. The electrode sheet according to claim 1, characterized in that, Along the preset direction, the width of the first insulating part is W1 mm, the width of the second insulating part is W2 mm, and the width of the uncoated area is W3 mm, satisfying 1.5≤W3 / W1≤10 and 1.6≤W3 / W2≤25.

8. A battery, characterized in that, At least including: A housing with an opening at the top; Electrode assembly disposed within the housing; as well as A cover plate assembly that seals the upper opening, the cover plate assembly including an adapter piece, the width direction of the adapter piece including a first electrode lug welding portion and a second electrode lug welding portion symmetrically arranged along the length direction of the adapter piece; The electrode assembly is formed by winding or stacking positive electrode sheets, a separator and negative electrode sheets, wherein the positive electrode sheet is the electrode sheet described in any one of claims 1-7; Along a predetermined direction, the electrode assembly includes a body and a tab, the tab including an uncoated area, a second insulating portion disposed on one side of the tab in the same thickness direction, and a portion of the first insulating portion; The number of electrode assemblies is two sets. The tabs of one set of electrode assemblies and the tabs of the other set of electrode assemblies are bent relative to each other and then welded to the first tab welding part and the second tab welding part of the adapter piece, respectively.

9. The battery according to claim 8, characterized in that, The electrode assembly includes a first adhesive tape disposed on the side of the tab facing away from the cover plate assembly. The first adhesive tape includes a first adhesive area, a second adhesive area, and a non-adhesive area located between the first adhesive area and the second adhesive area. The first adhesive area covers the main body, and the second adhesive area covers the uncoated area. In the thickness direction of the electrode assembly, the orthographic projections of the first insulating portion and the second insulating portion are completely located within the non-adhesive area.

10. An electronic device, characterized in that, Includes the battery as described in any one of claims 8-9.

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