Battery cell with winding structure, battery and manufacturing process of battery cell with winding structure

Abstract

The invention discloses a winding structure battery cell, a battery and a manufacturing process of the winding structure battery cell, the winding structure battery cell structure comprises a first pole piece, a second pole piece and a plurality of layers of diaphragms, the first pole piece and the second pole piece are insulated by the diaphragms, the first pole piece and the diaphragms on the two sides of the first pole piece are compounded at a winding starting position to form a composite layer, and the composite layer is formed by a plurality of layers of diaphragms. And the winding position of the composite layer and the winding position of the second pole piece form safe displacement on the battery cell. According to the winding structure battery cell, the battery and the manufacturing process of the winding structure battery cell, the head of the pole piece at the winding position and the diaphragm are compounded to form the composite layer, so that the diaphragm is prevented from being folded and folded due to relative displacement of the diaphragm and the pole piece at the winding position of the winding battery cell, the short-circuit risk is reduced, and the stability of the whole structure of the battery cell is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a wound structure battery cell, a battery, and a manufacturing process of the wound structure battery cell. Background Art

[0002] In today's booming energy industry, lithium-ion batteries are widely used in many fields such as portable electronic devices, electric vehicles, and large-scale energy storage systems due to their advantages such as high energy density and long cycle life. As a key structural form of lithium-ion batteries, the energy density of wound cells has attracted more and more attention. With the continuous improvement of the market's requirements for battery energy density, the traditional wound cell structure can no longer meet the needs of the application end, and a new wound structure cell is urgently needed. The existing cell structure, the traditional conventional wound cell structure, is to first clamp the diaphragm with a winding needle, pre-roll one circle of the diaphragm, and then wind the negative and positive electrode sheets to form a bare cell structure. The innermost electrode sheet structure of this cell is a negative-to-negative structure, which results in 6 layers of empty diaphragms and 2 layers of copper foil in the inner layer, resulting in a decrease in the volume energy density of the cell. Summary of the Invention

[0003] In response to the problems in the prior art, the present invention discloses a wound structure battery cell, a battery, and a manufacturing process for a wound structure battery cell to solve the problems of low safety and low volume energy density of the existing wound core structure.

[0004] The present invention is achieved through the following technical solutions:

[0005] The present invention first provides a wound structure battery cell, including a first pole piece, a second pole piece and several layers of diaphragms. The first pole piece and the second pole piece are insulated by the diaphragm. The first pole piece and the diaphragms on both sides of the first pole piece are combined to form a composite layer at the winding starting position. The winding starting position of the composite layer and the winding starting position of the second pole piece form a safe displacement on the battery cell.

[0006] As a further solution, the two pole tabs formed by the pole piece of a wound structure battery cell can appear on the same side or on opposite sides.

[0007] As a further solution, it includes a round winding core, a square winding core, a rectangular winding core or a special-shaped winding core adapted to the space inside the battery casing of various special electronic products.

[0008] As a further solution, the special-shaped core includes a triangular core, a trapezoidal core, a hexagonal core, a C-shaped core, a U-shaped core, etc.

[0009] As a further solution, in the circular winding core, the axial angle range between the rolling position of the composite layer and the rolling position of the second pole piece inside the battery core is 270° to 360°.

[0010] As a further solution, in the square winding core or the rectangular winding core, the rolling position of the composite layer and the rolling position of the second pole piece are arranged diagonally inside the battery core.

[0011] As a further solution, in the special-shaped winding core, the rolling-up position of the composite layer does not coincide with the rolling-up position of the second pole piece and is a preset safety displacement.

[0012] As a further solution, depending on the usage scenario or customer needs of the wound structure battery cell, the method of bonding the first electrode and the separators on both sides at the winding starting point is gluing, hot pressing, or welding. As a further solution, the separator is two layers, namely a first separator and a second separator, which are respectively located on both sides of the first electrode, and the polarity of the first electrode and the second electrode is opposite, that is, when the first electrode is a positive electrode, the second electrode is a negative electrode; correspondingly, when the first electrode is a negative electrode, the second electrode is a positive electrode.

[0013] The present invention also provides a battery, comprising a shell and the wound structure battery core.

[0014] As a further solution, the battery is a cylindrical battery, a rectangular battery or a special-shaped battery adapted to various special electronic products.

[0015] As a further solution, the cylindrical battery is placed inside the battery in a wound manner, so that the space inside the battery can be fully utilized, and can accommodate more active substances, thereby having a higher energy density and providing a relatively long usage time.

[0016] As a further solution, the prismatic battery's wound-structure cell is flat. The positive and negative electrodes and separator are wound flatly and then housed in a rectangular casing. This prismatic wound-structure cell allows for increased capacity by increasing length and width while maintaining an appropriate thickness. The resulting single-cell capacity is generally greater than that of a cylindrical battery, and assembly is relatively simple.

[0017] As a further solution, the rectangular battery can be divided into soft-pack rectangular battery, aluminum shell rectangular lithium battery, and steel shell rectangular lithium battery according to the outer packaging material; and can be divided into lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, lithium polymer and other rectangular batteries according to the positive electrode material.

[0018] As a further solution, the special-shaped batteries include geometric-shaped batteries, special-shaped batteries, ultra-thin batteries, and steel-shell special-shaped batteries.

[0019] As a further solution, geometric-shaped batteries include triangular batteries, trapezoidal batteries, hexagonal batteries, etc.; the corresponding internal core structure is determined by the structure of the shell, that is, the core structure of the triangular battery is a triangular core structure, the core structure of the trapezoidal battery is a trapezoidal structure, and the core structure of the hexagonal battery is a hexagonal structure.

[0020] As a further solution, special-shaped batteries include C-shaped batteries, U-shaped batteries, arc batteries, etc.; the core structure of the C-shaped battery is a C-shaped core, and the core structure of the U-shaped battery is a U-shaped core.

[0021] The present invention also provides a manufacturing process for forming the wound structure battery cell, comprising the following steps:

[0022] S1. Insert the first electrode piece between the first diaphragm and the second diaphragm to form a composite layer by winding with a needle winding mechanism, and the distance between the electrode piece and the diaphragm is ΔX.

[0023] S2, the composite mechanism composites the composite layer domain to form a composite layer;

[0024] S3, the second diaphragm is cut by the diaphragm cutting mechanism, and the winding needle mechanism extends to clamp the composite layer and pre-winds a layer of the second diaphragm on the composite layer;

[0025] S4. The right film roller moves toward the center to insert the second pole piece into the winding. At this time, the heads of the second pole piece and the first pole piece are distributed on both sides to form a relative position.

[0026] As a further solution, the specific method in S1 is: the first electrode piece is inserted between the first diaphragm and the second diaphragm by winding through a winding needle mechanism, and the left film roller is merged toward the center, so that the process length of the first diaphragm and the second diaphragm extended is X1, and the process length of the first electrode piece extended is X2, then the spacing distance between the extended diaphragm and the first electrode piece is ΔX=X1-X2.

[0027] As a further solution, the range of ΔXmm is 0.5mm-20mm.

[0028] As a further solution, the pre-winding angle range of the winding needle mechanism in S3 is 270-360°.

[0029] The characteristics and beneficial effects of the present invention are:

[0030] In terms of wound structure batteries,

[0031] (1) The electrode head and the diaphragm at the rolling position of the present invention are combined to form a composite layer, which avoids relative displacement between the diaphragm and the electrode at the rolling position of the wound battery cell, causing wrinkles and folds of the diaphragm, reduces the risk of short circuit, and improves the stability of the overall structure of the battery cell.

[0032] (2) Compared with the traditional conventional wound battery cell structure, the wound structure battery cell provided by the present invention can reduce 6 layers of empty diaphragms and 2 layers of copper foil in the inner layer of the battery cell, which can effectively improve the volume energy density of the battery cell.

[0033] In terms of batteries:

[0034] (1) The battery provided by the present invention can be implemented with the tabs on both sides or with the positive tab and the negative tab on opposite sides. In this way, when the battery is assembled in an electric vehicle, charging and discharging diversity on both sides can be achieved, thereby improving the flexibility and compatibility of the battery system.

[0035] In terms of the manufacturing process of winding structure battery cells:

[0036] (1) The manufacturing process provided by the present invention is to insert the first electrode piece between the two layers of diaphragms to form a composite layer by winding through a winding needle mechanism, and the distance extending from the diaphragm is greater than the spacing distance of the first electrode piece. This method reduces the length of the diaphragm as a whole and increases the length of the first electrode piece.

[0037] (2) The manufacturing process provided by the present invention pre-rolls the composite layer and then inserts a new electrode through a winding needle mechanism for winding. In this way, even if the electrode is slightly displaced or misaligned during subsequent use or production, it can effectively avoid short circuit of the battery cell caused by contact between the positive and negative electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 Schematic diagram of a wound structure battery cell according to an embodiment of the present invention;

[0040] Figure 2 is a schematic diagram of the existing winding core structure of the present invention;

[0041] Figure 3 is a schematic diagram of a composite layer forming process according to an embodiment of the present invention;

[0042] Figure 4 Schematic diagram of a process for manufacturing a wound structure battery cell according to an embodiment of the present invention;

[0043] Figure 5 yes Figure 4 Enlarged view of part B in the middle.

[0044] Description of the accompanying drawings:

[0045] 1-first pole piece; 2-second pole piece; 3-first diaphragm; 4-second diaphragm; 5-diaphragm; A-winding needle mechanism. DETAILED DESCRIPTION

[0046] In order to facilitate understanding of the present invention, the present invention will be described in more detail below, and embodiments of the present invention are given, but the scope of the present invention is not limited thereby.

[0047] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by those skilled in the art to which this application belongs. The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned descriptions of the drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application and the above-mentioned descriptions of the drawings do not have sequential meanings or distinctions of importance, but are used to distinguish different referents with the same name.

[0048] like Figure 2 As shown, the traditional wound cell structure is to first clamp the separator with a winding needle, pre-wind the separator once, and then wind the negative and positive electrode sheets to form a bare cell structure. The innermost electrode sheet structure of this cell is negative-to-negative, resulting in six additional layers of empty separator and two layers of copper foil in the inner layer, resulting in a lower volumetric energy density of the cell.

[0049] A wound structure battery cell, such as Figure 1 and Figure 3 As shown, it includes a first pole piece 1, a second pole piece 2 and several layers of diaphragms. The first pole piece 1 and the second pole piece 2 are insulated by a diaphragm. The first pole piece 1 and the diaphragms on both sides thereof are combined to form a composite layer at the winding starting position. The rolling position of the composite layer and the rolling position of the second pole piece 2 form a safe displacement on the battery cell. Compared with the traditional conventional winding battery cell structure, the winding structure battery cell provided by the present invention can reduce 6 layers of empty diaphragms and 2 layers of copper foil in the inner layer of the battery cell, which can effectively improve the volume energy density of the battery cell. At the same time, the pole piece head and the diaphragm at the rolling position are combined to form a composite layer, which can improve the stability of the overall structure of the battery cell, avoid the relative displacement of the diaphragm and the pole piece at the rolling position of the wound battery cell, and cause the diaphragm to wrinkle and fold, thereby reducing the risk of short circuit.

[0050] In the present invention, according to different usage scenarios or customer requirements of the wound structure battery cell, the first electrode 1 and the diaphragms on both sides thereof are combined at the winding starting position by gluing, hot pressing, or welding.

[0051] In the present invention, since the first pole piece 1 and the diaphragms on both sides thereof are thermally composited at the starting position of winding to form a composite layer, relative displacement during winding is avoided, and compared with batteries manufactured with traditional cell structures, safety is effectively improved.

[0052] In the present invention, the two tabs formed by the pole piece can appear on the same side or on opposite sides according to actual needs.

[0053] In the present invention, the tab formation process is as follows: During the winding process, the positive and negative electrode sheets and the separator are wound in a certain order to form a wound structure battery cell. At this time, the blank area on the electrode sheet (the tab) will be exposed on the same side or opposite sides of the winding core.

[0054] In the present invention, the diaphragm is two layers, namely the first diaphragm 3 and the second diaphragm 4. The first diaphragm 3 and the second diaphragm 4 are respectively located on both sides of the first electrode 1. The polarities of the first electrode 1 and the second electrode 2 are opposite, that is, when the first electrode 1 is the positive electrode, the second electrode 2 is the negative electrode; correspondingly, when the first electrode 1 is the negative electrode, the second electrode 2 is the positive electrode.

[0055] In the present invention, a wound structure battery cell can form a circular core, a square core, a rectangular core or a special-shaped core adapted to the space inside the battery casing of various special electronic products after winding.

[0056] In the present invention, the special-shaped core includes a triangular core, a trapezoidal core, a hexagonal core, a C-shaped core, a U-shaped core, and the like.

[0057] In the present invention, when a wound structure battery cell is wound to form a circular core, the axial angle range between the rolling position of the composite layer and the rolling position of the second pole piece 2 inside the battery cell is 270° to 360°.

[0058] In the present invention, when a wound structure battery cell is wound to form a square core or a rectangular core, the rolling position of the composite layer and the rolling position of the second pole piece 2 are arranged diagonally inside the battery cell.

[0059] In the present invention, when a wound structure battery cell is wound to form a special-shaped winding core that adapts to the space inside the battery shell of various special electronic products, the rolling position of the composite layer does not coincide with the rolling position of the second pole piece 2 and is a preset safety displacement.

[0060] As a specific example of the implementation of the present invention, a detailed case is provided as follows:

[0061] Example 1:

[0062] The first electrode piece 1 is the positive electrode piece, the second electrode piece 2 is the negative electrode piece, the diaphragm includes the first diaphragm 3 and the second diaphragm 4, and the first diaphragm 3 and the second diaphragm 4 are respectively located on both sides of the first electrode piece 1. After the battery cell is wound, a circular core is formed. The axial angle between the rolling position of the composite layer and the rolling position of the second electrode piece 2 inside the battery cell is 270°. Since the axial distance between the two is relatively far, the composite layer or the second electrode piece 2 may be slightly displaced or misaligned during subsequent use or production, which can also effectively avoid battery cell short circuit caused by contact between the positive and negative electrodes.

[0063] Example 2:

[0064] The first electrode 1 is the positive electrode, the second electrode 2 is the negative electrode, the diaphragm includes a first diaphragm 3 and a second diaphragm 4, and the first diaphragm 3 and the second diaphragm 4 are respectively located on both sides of the first electrode 1. After the battery cell is wound, a circular core is formed. The axial angle of the rolling position of the composite layer and the rolling position of the second electrode 2 inside the battery cell is less than 360° and greater than 270°. When the axial angle of the rolling position of the composite layer and the rolling position of the second electrode 2 inside the battery cell is 360°, that is, the axial angle of the rolling positions of the two is the same, but does not overlap, that is, the two are not in the same layer. When the composite layer or the second electrode 2 undergoes slight displacement or misalignment during subsequent use or production, it can also effectively avoid battery cell short circuit caused by contact between the positive and negative electrodes.

[0065] Example 3:

[0066] The first electrode piece 1 is the positive electrode piece, the second electrode piece 2 is the negative electrode piece, the diaphragm includes the first diaphragm 3 and the second diaphragm 4, and the first diaphragm 3 and the second diaphragm 4 are respectively located on both sides of the first electrode piece 1. After the battery cell is wound, a rectangular core is formed. The rolling position of the composite layer and the rolling position of the second electrode piece 2 are diagonally arranged inside the battery cell. The rolling positions of the two electrode pieces are the farthest circumferential distance apart in the same layer. This design allows the electrode pieces to be slightly displaced or misaligned during subsequent use or production, and can also effectively avoid battery cell short circuits caused by contact between the positive and negative electrodes.

[0067] Example 4:

[0068] The first electrode piece 1 is the positive electrode piece, the second electrode piece 2 is the negative electrode piece, the diaphragm includes the first diaphragm 3 and the second diaphragm 4, and the first diaphragm 3 and the second diaphragm 4 are respectively located on both sides of the first electrode piece 1. After the battery cell is wound, a trapezoidal winding core is formed to adapt to the space inside the battery shell of various special electronic products. The rolling position of the composite layer and the rolling position of the second electrode piece 2 are set diagonally inside the battery cell trapezoid. The rolling positions of the two electrode pieces are the farthest circumferential distance apart in the same layer. This design allows the electrode pieces to be slightly displaced or misaligned during subsequent use or production, and can also effectively avoid battery cell short circuits caused by contact between the positive and negative electrodes.

[0069] Example 5:

[0070] The first electrode piece 1 is the positive electrode piece, the second electrode piece 2 is the negative electrode piece, the diaphragm includes the first diaphragm 3 and the second diaphragm 4, and the first diaphragm 3 and the second diaphragm 4 are respectively located on both sides of the first electrode piece 1. After the battery cell is wound, a triangular core is formed. When the triangle is an equilateral triangle, the rolling position of the composite layer and the rolling position of the second electrode piece 2 are at any two corners of the battery cell triangle; when the triangle is a non-equilateral triangle, the rolling position of the composite layer and the rolling position of the second electrode piece 2 are located at the two corners with the farthest circumferential distance from each other on the same layer of the battery cell triangle. This design allows the electrode to be slightly displaced or misaligned during subsequent use or production, and can also effectively avoid battery cell short circuits caused by contact between the positive and negative electrodes.

[0071] Example 6:

[0072] The first electrode piece 1 is the positive electrode piece, the second electrode piece 2 is the negative electrode piece, the diaphragm includes the first diaphragm 3 and the second diaphragm 4, and the first diaphragm 3 and the second diaphragm 4 are respectively located on both sides of the first electrode piece 1. After the battery cell is wound, a hexagonal core is formed. The rolling position of the composite layer and the rolling position of the second electrode piece 2 are at two opposite corners inside the hexagon of the battery cell, so that the rolling positions of the two electrode pieces are at the farthest circumferential distance in the same layer. This design allows the electrode pieces to be slightly displaced or misaligned during subsequent use or production, and can also effectively avoid battery cell short circuits caused by contact between the positive and negative electrodes.

[0073] Example 7:

[0074] The first electrode piece 1 is the positive electrode piece, the second electrode piece 2 is the negative electrode piece, the diaphragm includes the first diaphragm 3 and the second diaphragm 4, and the first diaphragm 3 and the second diaphragm 4 are respectively located on both sides of the first electrode piece 1. After the battery cell is wound, a C-shaped core is formed. The rolling position of the composite layer and the rolling position of the second electrode piece 2 are at the two end points of the battery cell C-shape or at the upper and lower relative points, so that the rolling positions of the two electrode pieces are at the farthest circumferential distance in the same layer. This design allows the electrode pieces to be slightly displaced or misaligned during subsequent use or production, and can also effectively avoid battery cell short circuits caused by contact between the positive and negative electrodes.

[0075] Example 8:

[0076] The first electrode piece 1 is the positive electrode piece, the second electrode piece 2 is the negative electrode piece, the diaphragm includes the first diaphragm 3 and the second diaphragm 4, and the first diaphragm 3 and the second diaphragm 4 are respectively located on both sides of the first electrode piece 1. After the battery cell is wound, a U-shaped winding core is formed. The rolling position of the composite layer and the rolling position of the second electrode piece 2 are at the two end points of the U-shape of the battery cell, so that the rolling positions of the two electrode pieces are at the farthest circumferential distance in the same layer. This design allows the electrode pieces to be slightly displaced or misaligned during subsequent use or production, and can also effectively avoid battery cell short circuits caused by contact between the positive and negative electrodes.

[0077] A battery comprises a shell and the wound structure battery core.

[0078] In the present invention, the battery structure is a cylindrical battery, a square battery, a rectangular battery or a special-shaped battery adapted to various special electronic products.

[0079] The cylindrical battery provided by the present invention is placed inside the battery in a wound manner, so that the space inside the battery can be fully utilized, and can accommodate more active materials, thereby having a higher energy density and providing a relatively long service life.

[0080] The prismatic battery provided by the present invention features a flat wound cell structure. The positive and negative electrodes and separator are wound flatly and then housed in a rectangular housing. This prismatic wound cell structure allows for increased capacity by increasing length and width while maintaining an appropriate thickness. The resulting single cell capacity is generally greater than that of a cylindrical battery, and assembly is relatively simple.

[0081] The rectangular batteries provided by the present invention can be divided into soft-pack rectangular batteries, aluminum-shell rectangular lithium batteries, and steel-shell rectangular lithium batteries according to the outer packaging materials; and can be divided into lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, lithium polymer and other rectangular batteries according to the positive electrode materials.

[0082] In the present invention, the special-shaped batteries include geometric-shaped batteries, special-shaped batteries, ultra-thin batteries, and steel-shell special-shaped batteries.

[0083] In the present invention, geometric-shaped batteries include triangular batteries, trapezoidal batteries, hexagonal batteries, etc.; the corresponding core structure inside them is determined by the structure of the shell. Preferably, the core structure of the triangular battery is a triangular core structure, the core structure of the trapezoidal battery is a trapezoidal structure, and the core structure of the hexagonal battery is a hexagonal structure.

[0084] In the present invention, special shape batteries include C-shaped batteries, U-shaped batteries, arc batteries, etc. Preferably, the winding core structure of the C-shaped battery is a C-shaped winding core, and the winding core structure of the U-shaped battery is a U-shaped winding core.

[0085] The special-shaped battery provided by the present invention can also be used in Bluetooth headsets, etc. By being designed into a special shape, it can better utilize limited space and enhance the endurance of the lithium-ion battery.

[0086] A manufacturing process for a wound structure battery cell, such as Figure 4 and Figure 5 As shown, the following steps are included:

[0087] S1. Winding by the winding needle mechanism A, inserting the first pole piece 1 between the two layers of diaphragms to form a composite layer, and the distance between the protruding diaphragm and the first pole piece 1 is ΔX mm;

[0088] Specifically, the first electrode piece 1 is inserted between the first diaphragm 3 and the second diaphragm 4, and the left film rollers are merged toward the center, so that the process length of the first diaphragm 3 and the second diaphragm 4 extending out is X1mm, and the process length of the first electrode piece 1 extending out is X2mm. Then, the spacing distance between the extending diaphragm and the first electrode piece 1 is ΔXmm=X1mm-X2mm; this method reduces the length of the diaphragm as a whole and increases the length of the first electrode piece 1.

[0089] Preferably, the range of ΔXmm is 0.5mm-20mm.

[0090] As a specific example of the implementation of the present invention, a detailed case is provided as follows:

[0091] Insert the first electrode 1 between the first diaphragm 3 and the second diaphragm 4, and merge the left film rollers toward the center, so that the process length of the first diaphragm 3 and the second diaphragm 4 extending out is 1.5 mm, and the process length of the first electrode 1 extending out is 2 mm. The spacing distance between the extending diaphragm and the first electrode 1 is ΔXmm=2mm-1.5mm=0.5mm; this method reduces the length of the diaphragm as a whole and increases the length of the first electrode 1.

[0092] As a specific example of the implementation of the present invention, a detailed case is provided as follows:

[0093] Insert the first electrode 1 between the first diaphragm 3 and the second diaphragm 4, and merge the left and right film rollers toward the center, so that the process length of the first diaphragm 3 and the second diaphragm 4 extending out is 0.5 mm, and the process length of the first electrode 1 extending out is 2 mm. The spacing distance between the extending diaphragm and the first electrode 1 is ΔXmm=2mm-0.5mm=1.5mm; this method reduces the length of the diaphragm as a whole and increases the length of the first electrode 1.

[0094] As a specific example of the implementation of the present invention, a detailed case is provided as follows:

[0095] Insert the first electrode 1 between the first diaphragm 3 and the second diaphragm 4, and merge the left and right film rollers toward the center, so that the process length of the first diaphragm 3 and the second diaphragm 4 extending out is 3 mm, and the process length of the first electrode 1 extending out is 5 mm. The spacing distance between the extending diaphragm and the first electrode 1 is ΔXmm=5mm-3mm=2mm; this method reduces the length of the diaphragm as a whole and increases the length of the first electrode 1.

[0096] As a specific example of the implementation of the present invention, a detailed case is provided as follows:

[0097] Insert the first electrode 1 between the first diaphragm 3 and the second diaphragm 4, and merge the left film rollers toward the center, so that the process length of the first diaphragm 3 and the second diaphragm 4 extending out is 6 mm, and the process length of the first electrode 1 extending out is 10 mm. The spacing distance between the extending diaphragm and the first electrode 1 is ΔXmm=10mm-6mm=4mm; this method reduces the length of the diaphragm as a whole and increases the length of the first electrode 1.

[0098] As a specific example of the implementation of the present invention, a detailed case is provided as follows:

[0099] Insert the first electrode 1 between the first diaphragm 3 and the second diaphragm 4, and merge the left film rollers toward the center, so that the process length of the first diaphragm 3 and the second diaphragm 4 is 4 mm, and the process length of the first electrode 1 is 10 mm. The spacing distance between the protruding diaphragm and the first electrode 1 is ΔXmm=10mm-4mm=6mm; this method reduces the length of the diaphragm as a whole and increases the length of the first electrode 1.

[0100] As a specific example of the implementation of the present invention, a detailed case is provided as follows:

[0101] Insert the first electrode 1 between the first diaphragm 3 and the second diaphragm 4, and merge the left film rollers toward the center, so that the process length of the first diaphragm 3 and the second diaphragm 4 extending out is 10 mm, and the process length of the first electrode 1 extending out is 20 mm. The spacing distance between the extending diaphragm and the first electrode 1 is ΔXmm=20mm-10mm=10mm; this method reduces the length of the diaphragm as a whole and increases the length of the first electrode 1.

[0102] S2, the composite mechanism composites the composite layer domain to form a composite layer;

[0103] Specifically, the hot pressing mechanism sets the hot pressing temperature to [T1]°C (selected based on the material properties of the first electrode sheet and diaphragm), the pressure to [Y1] MPa, and the hot pressing time to [t1] seconds. After hot pressing, a composite layer is obtained, tightly bonded between the first electrode sheet 1 and the diaphragm. This process design of the composite layer avoids relative displacement during winding, significantly improving safety compared to batteries manufactured with traditional cell structures.

[0104] S3, the second diaphragm 4 is cut by the diaphragm cutting mechanism, and the winding needle mechanism extends to clamp the composite layer and pre-rolls a layer of diaphragm on the composite layer;

[0105] Preferably, the pre-winding angle range of the winding needle mechanism is 270°-360°;

[0106] S4. The right film roller moves toward the center to insert the second pole piece 2 for winding. At this time, the heads of the second pole piece 2 and the first pole piece 1 are distributed on both sides to form a relative position.

[0107] The composite layer of the separator and the first electrode 1 is pre-rolled, and the second electrode 2 is then inserted and wound using a winding needle mechanism, so that the second electrode 2 and the first electrode 1 are located on both sides of the battery cell. In this way, even if the electrode is slightly displaced or misaligned during subsequent use or production, it can effectively prevent the battery cell from short-circuiting due to contact between the positive and negative electrodes.

[0108] The present invention provides a manufacturing process for wound-structured battery cells that can be implemented with either tabs on both sides or with the positive and negative tabs located on opposite sides. This allows for diverse charging and discharging capabilities on both sides when the battery is assembled in an electric vehicle. For example, in certain special charging facilities or when the vehicle is in motion, charging and discharging can be performed from different sides as needed, improving the flexibility and compatibility of the battery system.

[0109] As a specific example of the implementation of the present invention, a detailed case is provided as follows:

[0110] Take the production of lithium-ion batteries for electric vehicles as an example. First, prepare the positive and negative electrodes according to the battery design requirements, as well as the separator material specifically for the battery. For the positive electrode, the positive active material is lithium cobalt oxide (LiCoO2, LCO), the thickness of the positive electrode is 70μm, and the negative active material is silicon-based material (Si / SiO x ), with a thickness of 89μm, and a diaphragm thickness of 9μm. During the manufacturing process, operations are carried out in accordance with the new wound battery cell head composite process. The negative electrode pole piece is placed between the two layers of diaphragm through the winding needle mechanism, and then the hot pressing mechanism goes deep into the head composite area for hot pressing and composite. The hot pressing temperature is set between 60-150°C (selected here according to the characteristics of the negative electrode pole piece and diaphragm material), the pressure is between 80-300MPa, and the hot pressing time is between 3-8S. After the hot pressing is completed, a composite layer in which the negative electrode pole piece and the diaphragm are tightly composited is obtained. The same operation is performed on the positive electrode pole piece in the same way.

[0111] In multiple simulated collision and vibration tests, no internal short circuit occurred, while 15% of batteries with traditional cell structures showed varying degrees of increased risk of internal short circuit in the same test. In terms of energy density, the theoretical capacity of lithium batteries in traditional silicon-based systems is 4200mah / g, while ours can reach 5200mah / g. The active material loading capacity of the cell provided by the present invention is increased by 20% compared with traditional cells, which increases the cruising range of electric vehicles by 100km-150km at the same power level. In terms of charge and discharge efficiency, the charging time of the new cell is shortened by 10%-15% compared with traditional cells, greatly improving the user's charging experience. Through this specific implementation case, it can be seen that this new winding structure cell and its manufacturing process have significant advantages in improving battery performance, safety, compatibility and other aspects.

[0112] In summary, the present invention provides a wound-structure battery cell with a composite layer formed by combining the electrode head and the diaphragm at the start of the winding process. This prevents relative displacement between the diaphragm and the electrode at the start of the winding process, which can lead to diaphragm wrinkling and folding, reduces the risk of short circuits, and improves the stability of the overall battery cell structure. Compared with conventional wound-structure batteries, the inner layer of the battery cell can be reduced by six layers of empty diaphragm and two layers of copper foil, effectively improving the volumetric energy density of the battery cell.

[0113] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A wound structure battery cell, characterized in that: It includes a first pole piece, a second pole piece and several layers of diaphragms. The first pole piece and the second pole piece are insulated by the diaphragm. The first pole piece and the diaphragms on both sides are combined to form a composite layer at the winding starting position. The winding starting position of the composite layer and the winding starting position of the second pole piece form a safe displacement on the battery cell.

2. A wound structure battery cell according to claim 1, characterized in that: The two tabs formed by the pole piece can appear on the same side or on opposite sides.

3. The wound structure battery cell according to claim 1, characterized in that: Including round cores, square cores, rectangular cores or special-shaped cores to adapt to the space inside the battery casing of various special electronic products.

4. A wound structure battery cell according to claim 4, characterized in that: In the circular winding core, the axial angle range between the rolling position of the composite layer and the rolling position of the second pole piece inside the battery core is 270° to 360°.

5. A wound structure battery cell according to claim 4, characterized in that: In the square winding core or the rectangular winding core, the rolling position of the composite layer and the rolling position of the second pole piece are arranged diagonally inside the battery core.

6. The wound structure battery cell according to claim 4, characterized in that: In the special-shaped winding core, the rolling-up position of the composite layer does not coincide with the rolling-up position of the second pole piece and is a preset safety displacement.

7. A battery, characterized in that: The invention comprises a shell and a wound structure battery core according to any one of claims 1 to 6.

8. The battery according to claim 7, characterized in that The battery is a cylindrical battery, a rectangular battery or a special-shaped battery adapted to various special electronic products.

9. A manufacturing process for forming a wound structure battery cell according to any one of claims 1 to 6, characterized in that: The steps include: S1. Insert the first electrode piece between the first diaphragm and the second diaphragm to form a composite layer by winding with a needle winding mechanism, and the distance between the electrode piece and the diaphragm is ΔX. S2, the composite mechanism composites the composite layer domain to form a composite layer; S3, the second diaphragm is cut by the diaphragm cutting mechanism, and the winding needle mechanism extends to clamp the composite layer and pre-rolls a layer of the second diaphragm on the composite layer; S4. The right film roller moves toward the center to insert the second pole piece into the winding. At this time, the heads of the second pole piece and the first pole piece are distributed on both sides to form a relative position.

10. The manufacturing process of the wound structure battery cell according to claim 9, characterized in that: The specific method in S1 is: the first electrode piece is inserted between the first diaphragm and the second diaphragm by winding through the needle winding mechanism, and the left film roller is merged toward the center, so that the process length of the first diaphragm and the second diaphragm extending out is X1, and the process length of the first electrode piece extending out is X2, then the spacing distance between the extending diaphragm and the first electrode piece is ΔX=X1-X2.

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