Composite separator, battery assembly and method of preventing slippage of electrode tabs

Abstract

The present disclosure relates to a composite separator, a battery assembly and a method for preventing the slippage of an electrode tab, comprising a main separator layer, at least one side edge of the main separator layer being provided with an edge functional area; the edge functional area comprises a guide inclined surface part and an adsorption unit, the adsorption unit has an adsorption surface with an adsorption force not lower than a preset adsorption force, the adsorption unit is integrated on at least part of the surface of the guide inclined surface part and extends towards the surface of the main separator layer; along the direction from inside to outside of the main separator layer, the thickness of the guide inclined surface part gradually increases; wherein the guide inclined surface part guides and laterally limits the position of the electrode tab, and the adsorption unit actively adsorbs the electrode tab, so as to jointly limit the slippage of the electrode tab relative to the main separator layer; after the electrode tab enters a predetermined position, the electrode tab is actively adsorbed and anchored, so that the relative position between the electrode tab and the composite separator is no longer maintained only by the winding tension, the lamination pressure or the electrolyte wetting force, and the edge positioning stability between the electrode tab and the separator is improved.

Description

Technical Field

[0001] This disclosure relates to the field of battery technology, and more specifically, to a composite separator, battery assembly, and electrode anti-slip anchoring method. Background Technology

[0002] Lithium-ion batteries are widely used in power batteries, energy storage batteries, and various portable electronic devices. The separator, located between the positive and negative electrodes, is a key functional component that primarily isolates the electrodes while allowing lithium ions to pass through. As power and energy storage batteries develop towards higher capacity, higher rate capability, and longer cycle life, the relative positional stability between the electrodes and the separator is increasingly important during winding, stacking, electrolyte injection, formation, and subsequent charge-discharge cycles. Especially under conditions such as high-speed winding or stacking assembly, vehicle vibration, and cyclic expansion and contraction of the cells, the stability of the fit between the electrode edges and the separator edges directly affects the battery's assembly consistency, safety, and lifespan.

[0003] In existing technologies, composite separators typically include polymer base films such as PP and PE, or functional layers such as ceramic coatings or polymer coatings on the base film surface to improve the separator's heat resistance, wettability, or mechanical strength. During cell assembly, the relative positioning between the electrodes and the separator usually relies on winding tension, stacking pressure, interfacial adhesion after electrolyte wetting, and the pressing effect of the electrode and separator themselves. However, the above positioning methods mainly apply to the large areas of the electrodes and separator, lacking an effective active anchoring structure for the electrode edges. When the cell is subjected to cyclic expansion and contraction, vibration impact, or high-speed assembly traction, the electrodes are prone to slight slippage relative to the separator, resulting in a deviation in the relative position between the electrode edges and the separator edges, affecting the separator's isolation and protection effect on the positive and negative electrodes.

[0004] Therefore, it is necessary to improve the diaphragm in the existing technology to solve the technical problem that the lack of an effective edge anchoring structure makes the electrode prone to slippage relative to the diaphragm. Summary of the Invention

[0005] The purpose of this disclosure is to provide a method for preventing slippage and anchoring of composite separators, battery modules, and electrode sheets, thereby solving the above-mentioned technical problems.

[0006] Other features and advantages of this disclosure will become apparent from the following detailed description, or may be learned in part from practice of this disclosure.

[0007] According to one aspect of this disclosure, a composite membrane is provided, including a main membrane layer, wherein at least one edge of the main membrane layer is provided with an edge functional area; The edge functional area includes a guide slope portion and an adsorption unit. The adsorption unit has an adsorption surface with an adsorption force not less than a preset adsorption force. The adsorption unit is integrated into at least a portion of the surface of the guide slope portion and extends toward the surface of the main diaphragm layer. Along the main diaphragm layer from the inside out, the thickness of the guide bevel gradually increases; The guide bevel provides position guidance and lateral restraint for the electrode, while the adsorption unit actively adsorbs the electrode to jointly limit the slippage of the electrode relative to the main membrane layer.

[0008] Optionally, the guide bevel has a first end close to the inner side of the main body membrane layer and a second end away from the inner side of the main body membrane layer, and the thickness of the guide bevel at the second end is greater than the thickness of the guide bevel at the first end; The thickness of the guide bevel portion ranges from 5% to 50% of the thickness of the main diaphragm layer.

[0009] Optionally, the guide bevel has a guide outer surface that is in contact with the same side surface of the main diaphragm layer, and the inclination angle of the guide outer surface relative to the same side surface of the main diaphragm layer is 30°-60°. Along the main diaphragm layer from the inside out, the relative distance between the guide outer surface and the same-side surface of the main diaphragm layer gradually increases.

[0010] Optionally, the two sides of the main diaphragm layer are respectively provided with edge functional areas, and a limiting space for the electrode edge to be arranged is formed between the two guide bevels; during assembly, the electrode is attached to the wall of the limiting space.

[0011] Optionally, the adsorption unit includes a micro-suction cup array, which includes a plurality of spaced-apart micro-suction cups; The micro-suction cups are recessed on the adsorption surface of the guide slope, and a plurality of the micro-suction cups are arranged along the extension direction of the guide slope.

[0012] Optionally, the adsorption unit includes a pressure-sensitive adsorption layer, which is applied to at least a portion of the surface of the guide slope; wherein the pressure-sensitive adsorption layer is made of pressure-sensitive adhesive material. The pressure-sensitive adsorption layer extends from the guide slope to the same side surface of the main diaphragm layer, and the outer surface of the pressure-sensitive adsorption layer constitutes the adsorption surface.

[0013] Optionally, the adsorption unit includes an electrostatic electret region, which is continuously or intermittently arranged along the extension direction of the guide slope, and is formed by high-voltage electret treatment.

[0014] Optionally, the guide bevel portion includes a transition base continuously disposed with the edge of the main body diaphragm layer and a thickened end located outside the transition base; The guide bevel extends along the length of the main diaphragm layer, and the cross-section of the guide bevel along the width of the main diaphragm layer has a wedge-shaped structure. The outer guide surface of the guide bevel extends obliquely from the transition base to the thickened end, and the oblique angle of the thickened end is greater than the oblique angle of the transition base.

[0015] The present invention also provides a method for anti-slip anchoring of electrode plates in a composite diaphragm, applied to the assembly of the composite diaphragm as described above; the method for anti-slip anchoring of electrode plates includes: Provide an electrode sheet, and wind or stack the electrode sheet with the composite separator, so that the edge of the electrode sheet moves along the guide bevel to the edge functional area, and the edge of the electrode sheet is in contact with the adsorption surface of the adsorption unit; The guide bevel provides positional guidance and lateral limitation to the edge of the electrode, and the adsorption unit actively adsorbs the edge of the electrode. After the electrode and the composite membrane form an electrode-membrane assembly, the edge of the electrode is kept in contact with the edge functional area to limit the lateral slippage of the electrode relative to the main membrane layer.

[0016] Optionally, during the process of winding or stacking the electrode sheet and the composite separator, the edge of the electrode sheet is made to enter the edge functional area along the guide bevel, and the edge of the electrode sheet and the edge functional area are arranged to correspond in the thickness direction. The edge of the electrode is attached to the guide bevel and the adsorption surface of the adsorption unit to form a local anchoring area between the edge of the electrode and the edge functional area.

[0017] The present invention also provides a battery assembly, including a composite separator and electrodes, wherein the composite separator and electrodes are assembled using the electrode anti-slip anchoring method described above.

[0018] As can be seen from the above technical solutions, the exemplary embodiments disclosed herein possess at least the following advantages and positive effects: In some embodiments of the present disclosure, the composite separator provides a guide slope with gradually increasing thickness at the edge of the main separator layer. This allows the electrode to be guided to a predetermined position along the guide slope during assembly and to be laterally restrained at the edge, reducing the possibility of electrode misalignment. Simultaneously, the adsorption unit is integrated into the guide slope and extends to the surface of the main separator layer. This allows the electrode to be actively adsorbed and anchored after it enters the predetermined position. This means that the electrode and the composite separator no longer rely solely on winding tension, stacking pressure, or electrolyte wetting force to maintain their relative position, thereby improving the edge positioning stability of the electrode, reducing electrode slippage caused by cyclic expansion and contraction, vibration, or high-speed assembly, reducing the risk of electrode edge misalignment, separator protection failure, and local short circuits, and improving battery assembly consistency and long-term reliability. This also enhances the edge positioning stability between the electrode and the separator.

[0019] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings: Figure 1 This is a schematic diagram of the assembly of the composite diaphragm and electrode in Example 1; Figure 2 for Figure 1 A magnified view of a portion of point A in the middle; Figure 3 This is a schematic diagram of the cross-sectional structure of the guide slope in Embodiment 1; Figure 4 This is a flowchart illustrating the method for preventing electrode slippage and anchoring of the composite diaphragm in Embodiment 8.

[0021] Illustration: Composite diaphragm 100, main diaphragm layer 110, guide inclined section 120, adsorption unit 130, adsorption surface 131, guide outer surface 121, transition base 122, thickened end 123; Electrode 200, positive electrode 210, negative electrode 220. Detailed Implementation

[0022] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be more thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art.

[0023] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this disclosure.

[0024] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0025] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0026] Example 1: Figure 1 This is a schematic diagram of the composite separator and electrode assembly in this embodiment. It shows that the composite separator 100 is disposed between the electrode 200. The electrode 200 includes a positive electrode 210 and a negative electrode 220. The edge position of the composite separator 100 is corresponding to the edge of the electrode 200, and a locally enlarged structure of the edge functional area is led out through point A.

[0027] Figure 2 for Figure 1 The enlarged schematic diagram at point A shows that the composite membrane 100 includes a main membrane layer 110 and an edge functional area 120 disposed at the edge of the main membrane layer 110. The edge functional area 120 includes a guide bevel portion 121 and an adsorption unit 130. The adsorption unit 130 includes a plurality of micro suction cups 131. The guide bevel portion 121 forms a relative spacing d with respect to the same side surface of the main membrane layer 110.

[0028] Figure 3This is a schematic diagram of the cross-sectional structure of the guide slope portion in this embodiment. It shows that the guide slope portion 121 gradually thickens from the inside to the outside along the width direction of the main diaphragm layer. The guide slope portion 121 includes a transition base portion 122 and a thickened end portion 123. The inclination angle b of the thickened end portion 123 is greater than the inclination angle a of the transition base portion 122.

[0029] like Figure 1 As shown, the present invention provides a composite separator 100, including a main separator layer 110, with an edge functional region provided on at least one side edge of the main separator layer 110. The composite separator 100 uses the main separator layer 110 as a basic support layer, and the main separator layer 110 can adopt a porous separator structure that meets the requirements of lithium-ion battery isolation and ion conduction. The edge functional region is provided in the edge region of the main separator layer 110, and this edge region is preferably the side region in the width direction of the main separator layer 110, rather than the end region in the length direction of the main separator layer 110. By providing an edge functional region at the edge of the main separator layer 110, the composite separator 100, in addition to its conventional function of isolating the positive and negative electrodes 200, can also form an auxiliary positioning structure at the edge position of the electrodes 200, thereby improving the relative positional stability of the electrodes 200 and the composite separator 100 after assembly. The electrode 200 includes a positive electrode 210 and a negative electrode 220, which are respectively integrated on the two end faces of the main separator layer 110.

[0030] The edge functional area includes a guide slope portion 120 and an adsorption unit 130. The adsorption unit 130 has an adsorption surface 131 with an adsorption force not less than a preset adsorption force. The adsorption unit 130 is integrated into at least a portion of the surface of the guide slope portion 120 and extends toward the surface of the main diaphragm layer 110.

[0031] A guide bevel 120 is formed at the edge of the main separator layer 110. Adsorption units 130 are integrated into at least a portion of the surface of the guide bevel 120 and further extend to the surface of the main separator layer 110, enabling the adsorption units 130 to form a continuous or substantially continuous contact area when the edge of the electrode 200 enters the edge functional area. The adsorption surface 131 refers to the surface of the adsorption unit 130 facing the electrode 200 and capable of forming an adsorption fit with the electrode 200. Its adsorption force can be preset according to the electrode 200 material, separator material, and cell assembly conditions to ensure that the edge of the electrode 200 does not easily shift relative to the main separator layer 110 after assembly.

[0032] Along the main diaphragm layer 110 from the inside out, the thickness of the guide bevel 120 gradually increases; the gradual increase in thickness along this direction creates a gradually thickened structure at the edge of the main diaphragm layer 110. The thickness of the guide bevel 120 can be understood as the relative distance d between the outer surface of the guide bevel 120 and the surface of the main diaphragm layer 110 on the same side, along the diaphragm thickness direction. This gradually thickened structure allows the edge of the electrode 200 to smoothly transition along the guide bevel 120 when approaching the edge of the composite diaphragm 100, reducing the possibility of direct collisions or misalignments at the edges of the electrode 200.

[0033] The guide slope portion 120 provides position guidance and lateral restraint for the electrode 200, while the adsorption unit 130 actively adsorbs the electrode 200 to jointly restrict the slippage of the electrode 200 relative to the main membrane layer 110.

[0034] It should be noted that when the composite separator 100 and the electrode 200 are wound or stacked, the edge of the electrode 200 first contacts the guide slope portion 120 and enters the predetermined position of the edge functional area under the structural guidance of the guide slope portion 120; subsequently, the adsorption surface 131 of the adsorption unit 130 forms an adsorption relationship with the edge of the electrode 200. Thus, the guide slope portion 120 mainly guides the position and limits the lateral movement of the edge of the electrode 200 from the structural morphology, while the adsorption unit 130 actively adsorbs the edge of the electrode 200 from the interfacial bonding relationship. The two work together to ensure that the edge of the electrode 200 no longer relies solely on winding tension, stacking pressure, or electrolyte wetting force to maintain its position, thereby reducing the risk of lateral slippage of the electrode 200 relative to the main separator layer 110.

[0035] The working principle of this invention is as follows: The composite separator 100, by providing a guide slope 120 with gradually increasing thickness at the edge of the main separator layer 110, allows the electrode 200 to be guided to a predetermined position along the guide slope 120 during assembly, and is laterally restrained at the edge, reducing the possibility of electrode 200 assembly misalignment. Simultaneously, the adsorption unit 130 is integrated into the guide slope 120 and extends to the surface of the main separator layer 110, enabling active adsorption and anchoring of the electrode 200 after it enters the predetermined position. This ensures that the relative position between the electrode 200 and the composite separator 100 is no longer solely dependent on winding tension, stacking pressure, or electrolyte wetting force, thereby improving the edge positioning stability of the electrode 200, reducing electrode 200 slippage caused by cyclic expansion and contraction, vibration, or high-speed assembly, reducing the risk of electrode 200 edge misalignment, separator protection failure, and local short circuits, and contributing to improved battery assembly consistency and long-term reliability; it also enhances the edge positioning stability between the electrode 200 and the separator.

[0036] In this embodiment, the guide slope portion 120 has a first end close to the inner side of the main diaphragm layer 110 and a second end away from the inner side of the main diaphragm layer 110. The thickness of the guide slope portion 120 at the second end is greater than the thickness of the guide slope portion 120 at the first end. The thickness of the guide slope portion 120 is in the range of 5%-50% of the thickness of the main diaphragm layer 110.

[0037] It should be noted that, specifically, the thickness of the guide bevel 120 refers to the relative distance d between the outer surface of the guide bevel 120 and the same-side surface of the main diaphragm layer 110 along the thickness direction of the diaphragm. The thickness range of the guide bevel 120 can be 5%-50% of the thickness of the main diaphragm layer 110. In one specific embodiment, the thickness of the main diaphragm layer 110 can be 5-20 μm, and the maximum relative distance d of the guide bevel 120 can be 0.5-2 μm. Thus, without significantly increasing the overall thickness of the composite diaphragm 100, a gradually thickened structure is formed at the edge of the diaphragm that allows for edge adhesion and positioning of the electrode 200.

[0038] As an optional embodiment, the guide slope portion 120 has a guide outer surface 121 that is in contact with the same side surface of the main diaphragm layer 110. The tilt angle of the guide outer surface 121 relative to the same side surface of the main diaphragm layer 110 is 30°-60°. Along the direction from the inside to the outside of the main diaphragm layer 110, the relative distance between the guide outer surface 121 and the same side surface of the main diaphragm layer 110 gradually increases.

[0039] The guide bevel portion 120 has a guide outer surface 121 that contacts the same side surface of the main diaphragm layer 110. The inclination angle of the guide outer surface 121 relative to the same side surface of the main diaphragm layer 110 is 30°-60°. Within this angle range, the guide outer surface 121 can form a relatively gentle transition path, avoiding abrupt contact between the edge of the electrode 200 and the edge of the diaphragm during winding or stacking. Furthermore, along the direction from the inside to the outside of the main diaphragm layer 110, the relative distance between the guide outer surface 121 and the same side surface of the main diaphragm layer 110 gradually increases; in one specific embodiment, the inclination angle of the guide outer surface 121 can be 45° to balance the smoothness of the electrode 200 edge sliding in and the edge lateral limiting effect.

[0040] In this embodiment, it is further explained that edge functional areas are respectively provided on both sides of the main diaphragm layer 110, and a limiting space for the edge arrangement of the electrode 200 is formed between the two guide inclined surfaces 120; during assembly, the electrode 200 is attached to the wall surface of the limiting space.

[0041] Specifically, the edge functional area can extend continuously along the length of the main diaphragm layer 110, and its width in the width direction of the main diaphragm layer 110 can be 2-5 mm, so that the edge functional area can cover the area where the edge of the electrode 200 is prone to displacement. By setting edge functional areas on both sides of the main diaphragm layer 110, the two edges of the electrode 200 in the width direction can be constrained respectively, thereby reducing the possibility of the electrode 200 being tilted as a whole or shifting locally in the width direction.

[0042] In this embodiment, the guide slope portion 120 includes a transition base 122 continuously disposed with the edge of the main body diaphragm layer 110 and a thickened end portion 123 located outside the transition base 122; It should be noted that the transition base 122 can be understood as a section of the guide slope 120 near the middle region of the main diaphragm layer 110, and its transition with the edge of the main diaphragm layer 110 is a continuous transition structure, rather than an abrupt step structure; the thickened end 123 is located on the side of the transition base 122 away from the middle region of the main diaphragm layer 110, and constitutes the part of the guide slope 120 near the outer edge of the composite diaphragm 100. By setting the transition base 122, the edge of the electrode 200 can first contact the gentler transition area when approaching the edge functional area, reducing the risk of the edge of the electrode 200 scraping, hitting, or misaligning with the edge of the diaphragm; by setting the thickened end 123, a clearer edge support and lateral limit can be formed after the edge of the electrode 200 enters the edge functional area, making it less likely for the edge of the electrode 200 to continue to shift outwards towards the composite diaphragm 100.

[0043] Combination Figure 2 As shown, the guide slope portion 120 extends along the length direction of the main diaphragm layer 110, and the cross section of the guide slope portion 120 along the width direction of the main diaphragm layer 110 has a wedge-shaped structure. In other words, the guide bevel 120 is not merely located at local points on the edge of the main diaphragm layer 110, but rather forms a continuous or substantially continuous edge strip structure along the length of the main diaphragm layer 110, thereby creating a stable guiding and limiting fit along the length of the electrode 200 edge. When viewed along the width of the main diaphragm layer 110, the cross-sectional thickness of the guide bevel 120 gradually increases from the end closer to the inner side of the main diaphragm layer 110 to the end closer to the outer side of the main diaphragm layer 110, thus forming a wedge-shaped cross-section. This wedge-shaped structure allows the edge of the electrode 200 to enter the predetermined position along the gradually changing thickness surface during winding or stacking, rather than directly crossing higher edge protrusions, which helps improve the smoothness and assembly consistency of the electrode 200 edge entering the edge functional area.

[0044] Combination Figure 3As shown, the guide outer surface 121 of the guide slope portion 120 extends obliquely from the transition base 122 to the thickened end 123, and the oblique angle b of the thickened end 123 is greater than the oblique angle a of the transition base 122.

[0045] Specifically, the guide outer surface 121 of the transition base 122 can be configured as a gentle slope with a small inclination angle to form the initial guide path for the edge of the electrode 200 to enter the edge functional area; the guide outer surface 121 of the thickened end 123 can be configured as a limiting section with a larger inclination angle to improve the lateral blocking ability of the edge of the electrode 200 after it enters. Since the inclination angle of the thickened end 123 is greater than that of the transition base 122, the guide outer surface 121 forms a two-stage inclined structure that gradually becomes steeper, allowing the edge of the electrode 200 to enter smoothly first, and then be subject to a stronger limiting effect near the outer edge. This structure balances the smoothness of the electrode 200 during assembly and the anti-slip stability after assembly.

[0046] Specifically, the transition base 122 can form a relatively gentle transition section, and the thickened end 123 can form a limiting section near the outer edge of the diaphragm. When the two are combined, the edge of the electrode 200 first smoothly enters the edge functional area along the transition base 122, and then the thickened end 123 provides more specific edge blocking and fitting support, thereby improving the positioning stability of the edge of the electrode 200 after assembly.

[0047] As an optional embodiment, the adsorption unit 130 includes a micro-suction cup array, which includes a plurality of spaced micro-suction cups; the micro-suction cups are recessed in the adsorption surface 131 of the guide slope portion 120, and the plurality of micro-suction cups are arranged along the extension direction of the guide slope portion 120.

[0048] Specifically, the micro-suction cups can be micro-cavity structures recessed on the adsorption surface 131 of the guide slope portion 120. Multiple micro-suction cups are arranged along the extension direction of the guide slope portion 120, thereby forming multiple dispersed adsorption contact points when the edge of the electrode 200 is attached to the guide slope portion 120. During assembly, when the edge of the electrode 200 is pressed against the micro-suction cup array, the gas or interfacial gaps within the micro-suction cups are squeezed out, creating a localized negative pressure or tight adhesion between the micro-suction cups and the edge of the electrode 200, thereby improving the adhesion stability between the edge of the electrode 200 and the edge functional area. This micro-suction cup array can be formed on the surface of the guide slope portion 120 by molding, embossing, or roll forming, making it suitable for implementation in conjunction with existing diaphragm processing technologies.

[0049] Example 2: The difference from Embodiment 1 is that the main diaphragm layer 110 is made of PP / PE composite base film and the thickness of the main diaphragm layer 110 is 12μm; the edge functional area extends continuously along the side of the main diaphragm layer 110 and the width of the edge functional area in the width direction of the main diaphragm layer 110 is 3mm; the maximum relative distance d of the guide inclined surface 120 is 1μm and the tilt angle of the guide outer surface 121 of the guide inclined surface 120 relative to the same side surface of the main diaphragm layer 110 is 45°.

[0050] Under this parameter combination, the main separator layer 110 has good flexibility and winding adaptability, and the width of the edge functional area can cover the area where the edge of the electrode 200 is prone to displacement. The guide slope portion 120 adopts a moderate thickening height and a moderate tilt angle, which can provide a smoother guide path and a more stable edge limiting effect for the edge of the electrode 200 without significantly increasing the overall thickness of the separator. It is suitable for the edge positioning of the electrode 200 in stacked cells or conventional wound cells.

[0051] Example 3: The difference from Embodiment 1 is that the main diaphragm layer 110 is a ceramic-coated diaphragm, which includes a 9μm base film and an Al2O3 ceramic coating disposed on the surface of the base film. The thickness of the ceramic coating is 2μm. The width of the edge functional area in the width direction of the main diaphragm layer 110 is 2mm. The maximum relative distance d of the guide beveled portion 120 is 0.5μm, and the tilt angle of the guide outer surface 121 of the guide beveled portion 120 relative to the same side surface of the main diaphragm layer 110 is 30°.

[0052] The composite separator 100 has a relatively small overall thickness, and the thickness increase and tilt angle of the guide bevel 120 are also relatively small. This helps to reduce local resistance between the electrode 200 and the composite separator 100 during high-speed winding, and reduces the possibility of warping or scratching when the edge of the electrode 200 passes through the edge functional area. At the same time, the ceramic coating can improve the heat resistance and dimensional stability of the main separator layer 110, making this embodiment more suitable for power battery scenarios with high requirements for assembly speed and thermal stability.

[0053] Example 4: The difference from Embodiment 1 is that the main diaphragm layer 110 is a polymer-coated diaphragm, and the total thickness of the main diaphragm layer 110 is 20 μm; the width of the edge functional area in the width direction of the main diaphragm layer 110 is 5 mm; the maximum relative spacing d of the guide beveled portion 120 is 2 μm, and the tilt angle of the guide outer surface 121 of the guide beveled portion 120 relative to the same side surface of the main diaphragm layer 110 is 60°.

[0054] The edge functional area has a large coverage width, and the guide slope 120 has a significant thickening structure and a large tilt angle, which can provide stronger edge support and lateral restraint for the edge of the electrode 200. This embodiment is suitable for battery products with large electrode 200 size, significant cyclic expansion and contraction amplitude, or complex vibration conditions, and is beneficial to improving the relative positional stability between the edge of the electrode 200 and the composite separator 100.

[0055] Example 5: In this embodiment, the adsorption unit 130 includes a micro-suction cup array, which comprises multiple spaced micro-suction cups; the diameter of each micro-suction cup is 20 μm, the depth is 3 μm, and the distribution density of the micro-suction cup array is 10. 4 pcs / mm 2 The inner wall of the micro-suction cup is covered with a modified PVDF layer with a thickness of 0.1 μm.

[0056] In this embodiment, the micro-suction cup array can be formed on the surface of the guide bevel 120 by a hot-press molding process. When the edge of the electrode 200 is attached to the guide bevel 120, the edge of the electrode 200 is pressed against the openings of multiple micro-suction cups, causing the air inside the micro-suction cups to be squeezed out, and forming a micro-negative pressure adsorption state between the micro-suction cups and the edge of the electrode 200; at the same time, the modified PVDF layer can improve the interfacial affinity between the inner wall of the micro-suction cup and the edge of the electrode 200. As a result, multiple micro-suction cups can form dispersed local adsorption points at the edge of the electrode 200, which, together with the lateral limiting effect of the guide bevel 120, improves the anti-slip stability of the edge of the electrode 200.

[0057] Example 6: The difference from Embodiment 1 is that the adsorption unit 130 includes a pressure-sensitive adsorption layer, which is applied to at least a portion of the surface of the guide slope portion 120; wherein the pressure-sensitive adsorption layer is made of pressure-sensitive adhesive; the pressure-sensitive adsorption layer extends from the guide slope portion 120 to the same side surface of the main diaphragm layer 110, and the outer surface of the pressure-sensitive adsorption layer constitutes the adsorption surface 131.

[0058] The thickness of the pressure-sensitive adsorption layer is 2 μm. The pressure-sensitive adsorption layer includes a lithium salt and a polymer matrix. The lithium salt is LiTFSI, and the polymer matrix is ​​a PEO-PVDF blend. The mass ratio of LiTFSI to PEO-PVDF blend is 3:7.

[0059] In this embodiment, the pressure-sensitive adsorption layer can remain in a solid or low-adhesion state at room temperature to reduce unintended adhesion of the separator during storage, transportation, and unwinding. When the electrode 200 and the composite separator 100 are wound or stacked, the edge of the electrode 200 is pressed against the pressure-sensitive adsorption layer under the action of winding tension, stacking pressure, or other assembly pressure, so that the pressure-sensitive adsorption layer and the edge of the electrode 200 form a localized bond and anchorage. Since the pressure-sensitive adsorption layer is located in the edge functional area, it mainly anchors the edge of the electrode 200 locally and does not cover a large area of ​​the central region of the main separator layer 110, which is beneficial to balance the positioning stability of the electrode 200 and the ion conduction performance of the main region of the composite separator 100.

[0060] Example 7: The difference from Embodiment 1 is that the adsorption unit 130 includes an electrostatic electret region, which is continuously or intermittently arranged along the extension direction of the guide slope 120, and is formed by high-voltage electret treatment.

[0061] The voltage for high-voltage electret treatment is 5-15kV, and the treatment time is 10-30s, which forms an electret region with a surface charge density of 1-5μC / m² on the 120 surface layer of the guide bevel.

[0062] In this embodiment, the electrostatic electret region is located on the surface of the guide bevel portion 120, enabling it to form an electrostatic adsorption fit with the edge of the metal foil in the electrode 200 when the edge of the electrode 200 enters the edge functional area. For the positive electrode 200, the electrostatic electret region can form an adsorption fit with the edge of the aluminum foil substrate; for the negative electrode 200, the electrostatic electret region can form an adsorption fit with the edge of the copper foil substrate. Since the electrostatic electret region does not require additional protrusion structures or adhesive layers, it can enhance the adhesion stability of the electrode 200 edges while maintaining the overall thinness of the composite separator 100, making it particularly suitable for cell structures that are sensitive to increases in separator thickness.

[0063] Comparison table of performance parameters of different embodiments of composite diaphragm 100 Example 8: Combination Figure 4 As shown, the present invention also provides a method for anti-slip anchoring of the electrode 200 of the composite diaphragm 100, applied to the assembly of the composite diaphragm 100 as described in Example 1; the method for anti-slip anchoring of the electrode 200 includes: S1, provide an electrode 200, and wind or stack the electrode 200 with the composite diaphragm 100, so that the edge of the electrode 200 moves along the guide slope 120 to the edge functional area, and the edge of the electrode 200 is attached to the adsorption surface 131 of the adsorption unit 130. As the electrode 200 moves relative to the composite diaphragm 100, the edge of the electrode 200 first contacts the guide slope 120 and gradually moves along the guide slope 120 to the edge functional area, causing the edge of the electrode 200 to enter the predetermined edge positioning area. At this time, the edge of the electrode 200 is in contact with or at least partially in contact with the adsorption surface 131 of the adsorption unit 130, thereby providing a contact basis for subsequent adsorption and anchoring. This step, through the gradient structure of the guide slope 120, allows the edge of the electrode 200 to enter the edge functional area more smoothly, reducing the contact, wrinkles, or misalignment between the edge of the electrode 200 and the edge of the composite diaphragm 100.

[0064] S2, the guide slope 120 forms position guidance and lateral limitation on the edge of the electrode 200, and the adsorption surface 131 of the adsorption unit 130 forms active adsorption on the edge of the electrode 200. Specifically, when the edge of the electrode 200 enters the edge functional area, the guide slope portion 120, relying on its own inclined thickening structure, guides and laterally limits the edge of the electrode 200, making it difficult for the edge of the electrode 200 to continue to shift outwards from the composite separator 100. Simultaneously, the adsorption surface 131 of the adsorption unit 130 forms an adsorption fit with the edge of the electrode 200, generating an active adsorption effect on the edge of the electrode 200. This active adsorption effect can manifest as micro-negative pressure adsorption, pressure-sensitive bonding adsorption, or electrostatic adsorption, depending on the specific form of the adsorption unit 130. Thus, the guide slope portion 120 provides structural limitation, and the adsorption unit 130 provides interfacial adsorption; both work together on the edge of the electrode 200, improving the relative fixation effect between the edge of the electrode 200 and the composite separator 100.

[0065] S3, after the electrode 200 and the composite diaphragm 100 form an electrode 200-diaphragm assembly, the edge of the electrode 200 is kept in contact with the edge functional area to limit the lateral slippage of the electrode 200 relative to the main diaphragm layer 110.

[0066] Specifically, after the electrode 200 and the composite separator 100 are wound or stacked to form the electrode 200-separator assembly, the edge of the electrode 200 remains attached to the edge functional area. At this time, the edge functional area is located at the corresponding position of the electrode 200 edge. The guide bevel 120 provides continuous edge support and lateral restraint for the electrode 200 edge, while the adsorption unit 130 maintains the adsorption connection between the electrode 200 edge and the composite separator 100. This prevents the electrode 200 from laterally slipping relative to the main separator layer 110 during subsequent handling, casing, liquid injection, formation, and charge-discharge cycles. This method reduces the risk of separator isolation and protection failure due to electrode 200 edge misalignment and improves the assembly consistency and long-term stability of the electrode 200-separator assembly.

[0067] In this embodiment, during the process of winding or stacking the electrode 200 and the composite diaphragm 100, the edge of the electrode 200 enters the edge functional area along the guide slope 120, and the edge of the electrode 200 and the edge functional area are correspondingly arranged in the thickness direction; the edge of the electrode 200 is attached to the guide slope 120 and the adsorption surface 131 of the adsorption unit 130 to form a local anchoring area between the edge of the electrode 200 and the edge functional area.

[0068] The corresponding setting in the thickness direction means that the edge of the electrode 200 is located above or below the edge functional area, and overlaps with the edge functional area in the thickness direction of the separator, so that the edge of the electrode 200 can make effective contact with the guide slope 120 and the adsorption surface 131 of the adsorption unit 130. As a result, a local anchoring area is formed between the edge of the electrode 200 and the edge functional area. This local anchoring area is mainly distributed at the edge of the electrode 200, without the need for overall bonding or fixing of the large-area main body area of ​​the electrode 200. This can improve the anti-slip ability of the edge of the electrode 200 and reduce the impact on the electrochemical performance and ion conduction performance of the main body area of ​​the electrode 200.

[0069] Example 9: The present invention also provides a battery assembly, including a composite separator 100 and an electrode 200, wherein the composite separator 100 and the electrode 200 are assembled using the electrode 200 anti-slip anchoring method as described in Example 1.

[0070] Specifically, the battery assembly can be a wound cell assembly or a stacked cell assembly. The electrode 200 includes a positive electrode 200 and a negative electrode 200, and the composite separator 100 is disposed between the positive electrode 200 and the negative electrode 200. After assembly, the edge of the electrode 200 enters the edge functional area of ​​the composite separator 100 and forms a bonding and anchoring relationship with the guide bevel 120 and the adsorption unit 130, so that the edge of the electrode 200 maintains a relatively stable position inside the battery assembly. By applying the above-mentioned composite separator 100 to the battery assembly, the risk of lateral slippage of the electrode 200 during winding, stacking, handling, casing, and subsequent charge and discharge cycles can be reduced, thereby improving the assembly consistency, edge isolation reliability, and long-term use stability of the battery assembly.

[0071] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims.

[0072] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A composite diaphragm, characterized in that, It includes a main diaphragm layer, wherein at least one edge of the main diaphragm layer is provided with an edge functional area; The edge functional area includes a guide slope portion and an adsorption unit. The adsorption unit has an adsorption surface with an adsorption force not less than a preset adsorption force. The adsorption unit is integrated into at least a portion of the surface of the guide slope portion and extends toward the surface of the main diaphragm layer. Along the main diaphragm layer from the inside out, the thickness of the guide bevel gradually increases; The guide bevel provides position guidance and lateral restraint for the electrode, while the adsorption unit actively adsorbs the electrode to jointly limit the slippage of the electrode relative to the main membrane layer.

2. The composite diaphragm according to claim 1, characterized in that, The guide bevel has a first end close to the inner side of the main diaphragm layer and a second end away from the inner side of the main diaphragm layer, and the thickness of the guide bevel at the second end is greater than the thickness of the guide bevel at the first end; The thickness of the guide bevel portion ranges from 5% to 50% of the thickness of the main diaphragm layer.

3. The composite diaphragm according to claim 2, characterized in that, The guide bevel has a guide outer surface that is in contact with the same side surface of the main diaphragm layer, and the inclination angle of the guide outer surface relative to the same side surface of the main diaphragm layer is 30°-60°. Along the main diaphragm layer from the inside out, the relative distance between the guide outer surface and the same-side surface of the main diaphragm layer gradually increases.

4. The composite diaphragm according to claim 1, characterized in that, The two sides of the main diaphragm layer are respectively provided with edge functional areas, and a limiting space for the electrode edge to be arranged is formed between the two guide bevels; during assembly, the electrode is attached to the wall of the limiting space.

5. The composite diaphragm according to claim 1, characterized in that, The adsorption unit includes a micro-suction cup array, which includes multiple micro-suction cups spaced apart. The micro-suction cups are recessed on the adsorption surface of the guide slope, and a plurality of the micro-suction cups are arranged along the extension direction of the guide slope.

6. The composite diaphragm according to claim 1, characterized in that, The adsorption unit includes a pressure-sensitive adsorption layer, which is applied to at least a portion of the surface of the guide slope; wherein the pressure-sensitive adsorption layer is made of pressure-sensitive adhesive material. The pressure-sensitive adsorption layer extends from the guide slope to the same side surface of the main diaphragm layer, and the outer surface of the pressure-sensitive adsorption layer constitutes the adsorption surface.

7. The composite diaphragm according to claim 1, characterized in that, The adsorption unit includes an electrostatic electret region, which is continuously or intermittently arranged along the extension direction of the guide slope. The electrostatic electret region is formed by high-voltage electret treatment.

8. The composite diaphragm according to claim 1, characterized in that, The guide slope includes a transition base that is continuously disposed with the edge of the main body membrane layer and a thickened end located outside the transition base; The guide bevel extends along the length of the main diaphragm layer, and the cross-section of the guide bevel along the width of the main diaphragm layer has a wedge-shaped structure. The outer guide surface of the guide bevel extends obliquely from the transition base to the thickened end, and the oblique angle of the thickened end is greater than the oblique angle of the transition base.

9. A method for anchoring and preventing slippage of the electrode sheet of a composite diaphragm, characterized in that, Applied to assembling the composite diaphragm as described in any one of claims 1 to 8; the electrode anti-slip anchoring method includes: Provide an electrode sheet, and wind or stack the electrode sheet with the composite separator, so that the edge of the electrode sheet moves along the guide bevel to the edge functional area, and the edge of the electrode sheet is in contact with the adsorption surface of the adsorption unit; The guide bevel provides positional guidance and lateral limitation to the edge of the electrode, and the adsorption unit actively adsorbs the edge of the electrode. After the electrode and the composite membrane form an electrode-membrane assembly, the edge of the electrode is kept in contact with the edge functional area to limit the lateral slippage of the electrode relative to the main membrane layer.

10. A battery assembly, characterized in that, It includes a composite diaphragm and an electrode, which are assembled using the electrode anti-slip anchoring method as described in claim 9.

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