Coating gasket for full-tab battery

Abstract

The utility model relates to a coating gasket for a full-tab battery, which is used for being clamped at a discharge hole of a coating machine so as to realize directional spreading of slurry on a coating surface through capillary effect and shear force control in a use process. The coating gasket comprises a gasket base body and a plurality of gasket side parts extending outwards from one side of the gasket base body, every two adjacent gasket side parts form a groove-shaped coating area, and in the gasket side parts, the groove-shaped coating area is formed by the gasket side parts. And one end of each gasket side part except the first gasket side part and the last gasket side part is provided with a double-choked flow structure so as to form a stepped flow resistance structure. The device can effectively improve the lithium precipitation phenomenon of the full-tab battery.

Description

Technical Field

[0001] This utility model belongs to the field of battery manufacturing technology, specifically relating to a coated pad for a multi-tab battery. Background Technology

[0002] All-tab batteries represent a high-performance battery design with higher energy density and faster charge / discharge rates. However, unlike traditional interleaved gap coating, all-tab coating employs a vertically interleaved continuous coating process. During the start-up and shutdown phases of the coating die, the slurry undergoes abrupt changes in rheological behavior, creating a localized thickness spike (up to 1.5 times the normal area) in the gap transition region. This results in a gradient in the distribution of active materials, leaving insufficient space for the negative electrode to receive lithium ions during charge and discharge, leading to lithium plating. Lithium plating not only degrades battery performance but also increases internal resistance, shortens battery life, and may even cause safety hazards such as short circuits and explosions. Therefore, improving lithium plating in all-tab batteries has become a crucial issue urgently needing resolution in the current battery technology field. Utility Model Content

[0003] To address the aforementioned problems in the prior art, this utility model provides a coated pad for multi-tab batteries. The technical problem to be solved by this utility model is achieved through the following technical solution:

[0004] This utility model provides a coating pad for a multi-tab battery. The coating pad is used to be clamped at the discharge port of a coating machine. The coating pad includes a pad substrate and a plurality of pad sides extending outward from one side of the pad substrate. Two adjacent pad sides form a groove-shaped coating area. Among the plurality of pad sides, except for the first pad side and the last pad side, one end of each pad side is provided with a double flow-blocking structure to form a stepped flow-blocking structure.

[0005] Optimally, the dual flow-blocking structure includes: a first flow-blocking block and a second flow-blocking block with identical structures, wherein the first flow-blocking block and the second flow-blocking block are symmetrically arranged on both sides of a gasket side.

[0006] Ideally, the first flow-blocking block is in the shape of a rectangular sheet.

[0007] Ideally, each gasket side, except for the first and last gasket sides, has the same structure, which is a rectangular sheet structure.

[0008] Ideally, along the thickness direction of the gasket substrate, the thickness difference between each gasket side (excluding the first gasket side and the last gasket side) and the first or second flow-blocking block disposed thereon is 0.195 mm to 0.205 mm.

[0009] Ideally, the first gasket side and the last gasket side are mirror symmetrical. The first gasket side or the last gasket side includes a long gasket and a short gasket that are perpendicular to each other. One end of the long gasket is connected to the gasket base, and the other end is connected to one end of the short gasket. The long gasket is provided with a plurality of first through holes at intervals.

[0010] Ideally, the number of the plurality of first through holes is 2.

[0011] Ideally, the gasket substrate is a rectangular sheet structure, and multiple sets of periodic through-hole arrays are evenly spaced on the surface of the gasket substrate along its length.

[0012] Ideally, each set of periodic through-hole arrays includes three second through-holes arranged parallel to the length direction of the gasket substrate, and the diameter of the first through-hole is equal to the diameter of the second through-hole.

[0013] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0014] To address the problem of localized thickness peaks in existing coating pads during coating, which leads to severe lithium plating in subsequent all-tab batteries, this invention provides a coating pad for all-tab batteries. This pad innovatively solves the slurry accumulation problem in the all-tab battery coating process through the synergistic effect of a stepped flow resistance structure and optimized fluid dynamics: the symmetrical layout of the dual flow resistance blocks, combined with precise thickness difference control, creates a dynamic shear force field during coating, accurately stripping redundant slurry from gap areas, resulting in a smooth transition of the coating from the center to the edge; simultaneously, the periodic through-hole array and the grooved coating area work together to regulate the slurry flow state and suppress uneven distribution of active materials. This design eliminates localized thickness peaks, ensuring optimized capacity matching between the positive and negative electrodes and suppressing lithium-ion oversaturation deposition under fast charging conditions from the source; its established ion flux balancing mechanism improves electrode interface stability, significantly extends battery cycle life, and enhances thermal safety performance, providing a core process guarantee for the compatibility of high energy density and high rate performance in all-tab batteries. Attached Figure Description

[0015] Figure 1 This is a front view of a coated pad for a multi-tab battery provided by this utility model;

[0016] Figure 2 This is a side view of a coated pad for a multi-tab battery provided by this utility model;

[0017] Figure 3 This is a partial enlarged view of the coated gasket provided by this utility model.

[0018] Figure label:

[0019] 1. Coated gasket; 11. Gasket substrate; 12. Several gasket sides; 13. Double flow-blocking structure; 131. First flow-blocking block; 132. Second flow-blocking block. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0021] The following is a detailed description of a coated pad for a multi-tab battery proposed in this utility model, with reference to the accompanying drawings.

[0022] Figure 1 This is a front view of a coated pad for a multi-tab battery provided by this utility model; Figure 2 This is a side view of a coated pad for a multi-tab battery provided by this utility model. Figure 1 and Figure 2 As shown, the coating pad 1 is used to be clamped at the outlet of the coating machine (not shown in the figure) so as to achieve the directional spreading of the slurry on the coating (not shown in the figure) surface through capillary effect and shear force control during use; the coating pad 1 includes: a pad substrate 11, and a plurality of pad side portions 12 extending outward from one side of the pad substrate 11. Two adjacent pad side portions form a groove-shaped coating area. Among the plurality of pad side portions 12, except for the first pad side portion and the last pad side portion, one end of each pad side portion is provided with a double flow-blocking structure 13 to form a stepped flow-blocking structure.

[0023] Here, the gasket substrate 11 is a rectangular sheet structure made of stainless steel and is manufactured by integral stamping. Along the length of the gasket substrate 11, multiple sets of periodic through-hole arrays are evenly spaced on the surface of the gasket substrate 11, and each set of periodic through-hole arrays includes three second through holes arranged parallel to the length of the gasket substrate.

[0024] Here, the first gasket side and the last gasket side are mirror-symmetrical. Each gasket side includes a long gasket and a short gasket perpendicular to each other. One end of the long gasket is connected to the gasket base, and the other end is connected to one end of the short gasket. The long gasket has a plurality of first through holes spaced apart. The diameter of each first through hole is equal to the diameter of a second through hole. For example, the number of the plurality of first through holes is two.

[0025] Please continue to refer to Figure 1 and Figure 2Except for the first and last gasket sides, each gasket side has the same structure, which is a rectangular sheet structure. For example, the number of the middle gasket sides is 2, the distance between two adjacent gasket sides in the length direction of the gasket substrate is 106.5±0.5mm, and the gap width between two adjacent coating areas is 5.5±0.5mm.

[0026] Here, each gasket at the middle position has a double flow-blocking structure 13 at its side end. To clearly see the double flow-blocking structure 13, Figure 3 This is a partially enlarged view of the coated gasket provided by this utility model. (See attached image.) Figure 3 As shown, the dual flow-blocking structure 13 includes a first flow-blocking block 131 and a second flow-blocking block 132 with identical structures, symmetrically arranged on both sides of a gasket side. The first flow-blocking block 131 is rectangular in shape. Further, along the thickness direction of the gasket substrate 11, the thickness difference between each gasket side (excluding the first and last gasket sides) and the first flow-blocking block 131 or the second flow-blocking block 132 disposed thereon is 0.195 mm to 0.205 mm. For example, the thickness of the first flow-blocking block 131 is 0.6 mm, and the thickness of the gasket side is 0.8 mm. It should be noted that the thickness of the gasket side is the same as the thickness of the gasket substrate.

[0027] The above is a detailed structural description of the coated pad. Now, with reference to the embodiments, the process of how the coated pad improves the lithium plating phenomenon in the all-tab battery will be described.

[0028] First, one end of the undistributed pad side of the coating pad is clamped at the outlet of the coating machine to ensure that the slurry flows in the grooves formed by the multiple pad sides. During use, the coating machine drives the pad to coat the material vertically and evenly, with a coating thickness of A. Before the addition of the double flow-blocking structure, due to the fluidity of the slurry, local thickness peaks accumulate in the gaps between adjacent coating areas, and the height of these local thickness peaks is greater than A. After the addition of the double flow-blocking structure, during the downward movement of the coating machine, the stepped flow-blocking structure formed by the double flow-blocking structure and the pad sides will scrape away some slurry from the side edges of the coating area, resulting in a phenomenon of thicker slurry in the middle and thinner slurry on both sides. Specifically, the thickness of the slurry at the middle position in the coating area is A (0.09 mm), and the thickness at the edge position is B (0.08 mm), where B is less than A. Due to the fluidity of the slurry, the thickness at the middle position will eventually be the same as the thickness at the edge position. Even though local thickness peaks may still appear during the coating process, the use of a stepped flow resistance structure to thin these local thickness peaks can ensure overall thickness uniformity and effectively improve the lithium plating phenomenon in all-tab batteries.

[0029] It should be understood that when using the coated pad provided by this utility model as a positive electrode pad, it can improve the lithium plating phenomenon in all-tab batteries. When used as a negative electrode pad, it can prevent roll breakage and cycle expansion breakage. Here, roll breakage mainly manifests as continuous mechanical fracture of battery electrodes during the roll forming process caused by material defects (such as dark cracks in the substrate, insufficient coating adhesion), process parameter mismatch (pressure exceeding limits, sudden changes in linear speed), or abnormal equipment status (roller system skew, correction failure). Specific characteristics include sudden tearing of the electrode in the transverse or longitudinal direction, irregular burrs or delamination at the fracture edge, and accompanying debris accumulation contaminating the roll gap. This phenomenon directly leads to the interruption of electrode production, a large waste of materials, and the difficulty in repairing the broken area easily causes microcrack propagation and uneven coating thickness in subsequent processes, ultimately resulting in battery capacity decay, shortened cycle life, and a sharp increase in safety hazards. Cyclic expansion fracture mainly manifests as the accumulation of stress inside the electrode due to the repeated lithium insertion / extraction of the active material (such as silicon-based anode) during long-term charge-discharge cycles, which causes volume expansion and contraction (expansion rate > 300%). Specific characteristics include the gradual formation of network microcracks on the electrode surface, which expand into penetrating transverse fractures. The fracture surface exhibits irregular serrated delamination or coating peeling. Accompanying this is the infiltration of electrolyte along the cracks, which causes the active material to pulverize and deactivate. The battery's internal resistance increases sharply (increase > 50%), and the capacity decays rapidly (loss > 1% per cycle). In severe cases, the fracture fragments pierce the separator, causing local short circuits, accompanied by gas bulging and signs of impending thermal runaway (abnormal temperature fluctuations > 5℃ / min), ultimately leading to the complete loss of battery function.

[0030] To address the problem of localized thickness peaks in existing coating pads during coating, which leads to severe lithium plating in subsequent all-tab batteries, this invention provides a coating pad for all-tab batteries. This pad innovatively solves the slurry accumulation problem in the all-tab battery coating process through the synergistic effect of a stepped flow resistance structure and optimized fluid dynamics: the symmetrical layout of the dual flow resistance blocks, combined with precise thickness difference control, creates a dynamic shear force field during coating, accurately stripping redundant slurry from gap areas, resulting in a smooth transition of the coating from the center to the edge; simultaneously, the periodic through-hole array and the grooved coating area work together to regulate the slurry flow state and suppress uneven distribution of active materials. This design eliminates localized thickness peaks, ensuring optimized capacity matching between the positive and negative electrodes and suppressing lithium-ion oversaturation deposition under fast charging conditions from the source; its established ion flux balancing mechanism improves electrode interface stability, significantly extends battery cycle life, and enhances thermal safety performance, providing a core process guarantee for the compatibility of high energy density and high rate performance in all-tab batteries.

[0031] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0032] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the present invention's conception through the foregoing teachings or related technical or knowledge. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A coated gasket for use in a full tab cell, characterized by, The coating pad is used for being arranged at the discharge port of a coating machine, and comprises a pad base and a plurality of pad sides extending outward from one side of the pad base, and each adjacent two pad sides forms a groove-shaped coating area, wherein, one end of each pad side except the first pad side and the last pad side is provided with a double flow resistance structure to form a stepped flow resistance structure.

2. The coated gasket for a full tab cell of claim 1, wherein, The double flow resistance structure comprises a first flow resistance block and a second flow resistance block which are symmetrically arranged on both sides of the pad side.

3. The coated gasket for a full-ear cell of claim 2, wherein, The first flow resistance block is in the shape of a rectangular sheet.

4. The coated gasket for a full-ear cell of claim 3, wherein, Each pad side except the first pad side and the last pad side is in the shape of a rectangular sheet.

5. The coated gasket for a full-ear cell of claim 4, wherein, The thickness difference between each pad side except the first pad side and the last pad side and the first flow resistance block or the second flow resistance block arranged thereon along the thickness direction of the pad base is 0.195mm-0.205mm.

6. The coated gasket for a full-ear cell of claim 1, wherein, The first pad side and the last pad side are mirror-symmetric, and the first pad side or the last pad side comprises a long pad and a short pad which are perpendicular to each other, one end of the long pad is connected with the pad base, the other end is connected with one end of the short pad, and a plurality of first through holes are arranged on the long pad at intervals.

7. The coated gasket for a full-ear battery of claim 6, wherein, The number of the plurality of first through holes is 2.

8. The coated gasket for a full-ear cell of claim 6, wherein, The pad base is in the shape of a rectangular sheet, and a plurality of groups of periodic through hole arrays are arranged on the surface of the pad base at equal intervals along the length direction of the pad base.

9. The coated gasket for a full-ear battery of claim 8, wherein, Each group of periodic through hole arrays comprises three second through holes which are arranged parallel to the length direction of the pad base, and the diameter of the first through hole is equal to the diameter of the second through hole.

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