Winding type lithium ion battery roll core, manufacturing method thereof and lithium ion battery

Abstract

The invention provides a winding type lithium ion battery roll core, a manufacturing method thereof and a lithium ion battery. The winding type lithium ion battery roll core comprises a positive pole piece and a negative pole piece, wherein the positive pole piece comprises discontinuous positive pole unit pieces (2) and continuous positive pole pieces (6); the negative pole piece comprises discontinuous negative pole unit pieces (1) and continuous negative pole pieces (5); the diaphragm (3) is arranged between the positive pole piece and the negative pole piece; the two R-angle supporting structures (4) are located at the two R angles of the innermost layer of the battery roll core, and at least part of the positive electrode unit pieces (2) and at least part of the negative electrode unit pieces (1) are stacked between the two R-angle supporting structures (4). According to the winding type lithium ion battery roll core and the manufacturing method thereof, the problem that the inner-layer pole piece of the battery roll core cracks and falls off at the bent part can be effectively solved, and the safety and reliability of the battery are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a wound lithium-ion battery core and a manufacturing method thereof, and a lithium electronic battery. Background Art

[0002] As an advanced rechargeable battery technology, lithium-ion batteries have rapidly become the preferred power source for portable electronic devices, power tools, drones and even new energy vehicles since they were commercialized in the 1990s due to their high operating voltage, high specific energy, low self-discharge rate and long cycle life. With the global trend of pursuing sustainable development and reducing carbon emissions, the sales of new energy vehicles have surged, and the demand for high-performance and high-energy-density power batteries has become increasingly urgent, driving the lithium-ion battery industry towards higher efficiency, lower cost and better performance.

[0003] In the production process of square lithium-ion batteries, winding and lamination are the two main electrode assembly technologies. Among them, the winding process is widely used due to its long history of development, mature process flow, low production cost, high product yield and significant production efficiency. The winding process forms a compact core structure by alternately winding the positive electrode sheet, the negative electrode sheet and the separator, which is conducive to improving the energy density and volume utilization of the battery.

[0004] However, the production of wound lithium-ion battery cores also has certain limitations. After winding, in order to ensure the dimensional stability of the battery and the tightness of the internal structure, the core is usually required to be pressurized and shaped, which can be achieved by cold pressing or hot pressing. However, this treatment method will cause the 1-5 circles of the pole pieces in the inner layer of the core to be subjected to greater stress at the R corner (i.e., the outer fillet of the core) due to the small bending radius, resulting in cracking and falling of the positive and negative pole pieces in these areas. Cracking and falling not only affect the structural integrity of the battery, but may also cause internal short circuits in the battery cell, and even precipitate metallic lithium during charging or discharging, affecting the safety and cycle life of the battery. Summary of the invention

[0005] The main purpose of the present invention is to provide a wound lithium-ion battery core and a manufacturing method thereof, and a lithium electronic battery, which can effectively solve the problem of cracking and falling of the inner electrode sheet of the battery core at the bending point, thereby improving the safety and reliability of the battery.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, there is provided a wound lithium-ion battery core, comprising: a positive electrode sheet, comprising a discontinuous positive electrode unit sheet and a continuous positive electrode sheet; a negative electrode sheet, comprising a discontinuous negative electrode unit sheet and a continuous negative electrode sheet; a diaphragm, arranged between the positive electrode sheet and the negative electrode sheet to form a gap; two R-angle support structures, the continuous positive electrode sheet is wrapped around the outer periphery of the positive electrode unit sheet, and the continuous negative electrode sheet is wrapped around the outer periphery of the negative electrode unit sheet, the two R-angle support structures are located at the two R-angles of the innermost layer of the battery core, at least part of the positive electrode unit sheet and at least part of the negative electrode unit sheet are stacked between the two R-angle support structures, which effectively prevents the inner electrode sheet from cracking and falling off at the bending part of the R angle, and accelerates the infiltration of the electrolyte.

[0007] In one embodiment, the R-angle support structure is provided with a central hole penetrating at least one end along the length direction, and holes are opened on the hole wall of the central hole. This design is conducive to the penetration of electrolyte, accelerates the diffusion of electrolyte inside the winding core, and increases the electrolyte infiltration speed, thereby improving the electrochemical performance of the battery and shortening the pretreatment time of the battery.

[0008] In one embodiment, the R angle support structure includes a flat plate segment and an arc plate segment, the arc plate segment is fixedly connected to the flat plate segment and is located on the side of the flat plate segment away from the positive electrode unit sheet and the negative electrode unit sheet. The combination of the flat plate segment and the arc plate segment allows the R angle support structure to provide support without affecting the normal winding of the winding core, and its arc design helps to increase the bending radius of the pole piece and avoid cracking.

[0009] In one embodiment, the length of the R angle support structure is the same as the length of the negative electrode unit sheet, the thickness is equal to the sum of the thickness of the positive electrode unit sheet and the negative electrode unit sheet, and the width of the separator between adjacent negative electrode unit sheets is equal to the outer circumferential arc length of the arc-shaped plate segment. By accurately matching the size of the R angle support structure and the size of the electrode sheet, the accurate placement of the R angle support structure at the innermost R angle position is ensured, while avoiding dead angles during the electrolyte infiltration process, which is conducive to uniform electrolyte infiltration.

[0010] In one embodiment, the battery injection port is aligned with the center hole of the R-angle support structure and is connected to the center hole. This design allows the electrolyte to penetrate directly from the hole of the R-angle support structure, accelerates the diffusion speed of the electrolyte into the core, shortens the battery pretreatment time, and is also conducive to improving the utilization rate of the electrolyte.

[0011] In one embodiment, the material of the R angle support structure can be selected from one or more of PP, PE, and PET. These materials have good chemical stability and high temperature resistance, are suitable for the internal environment of the battery, and have good thermal melt properties with the diaphragm, thereby ensuring the fixing effect of the R angle support structure.

[0012] In one embodiment, the number of positive electrode unit sheets and negative electrode unit sheets is 2 to 10, and the width of the positive electrode unit sheet is 3 mm to 4 mm smaller than that of the negative electrode unit sheet. This design ensures that the negative electrode completely covers the positive electrode, avoids lithium plating during overcharging or overdischarging of the lithium-ion battery, and improves the safety and cycle performance of the battery.

[0013] According to another aspect of the present invention, a method for making the above-mentioned wound lithium-ion battery roll core is provided, comprising: preparing positive electrode sheets, negative electrode sheets and separators, wherein the positive electrode sheets include positive electrode unit sheets and continuous positive electrode sheets, and the negative electrode sheets include negative electrode unit sheets and continuous negative electrode sheets; preparing R-angle support structures; fixing the R-angle support structures at the R-angle position of the separator before winding; winding the positive electrode unit sheets and the negative electrode unit sheets so that the positive electrode unit sheets and the negative electrode unit sheets are stacked between the two R-angle support structures, and the separators between adjacent positive electrode unit sheets and the separators between adjacent negative electrode unit sheets are coated outside the R-angle support structures. This method solves the problem of cracking and falling of the inner layer of the roll core by introducing the R-angle support structure, while optimizing the infiltration of the electrolyte and improving the overall performance of the battery.

[0014] In one embodiment, before the step of winding the positive electrode unit sheet and the negative electrode unit sheet, the step further includes: pre-rolling the separator to position the R angle support structure at the R angles on both sides of the innermost layer of the winding core. The step of pre-rolling the separator ensures the accurate positioning of the R angle support structure, avoiding the problem of electrode damage or poor electrolyte infiltration caused by inaccurate positioning.

[0015] In one embodiment, the steps of preparing the positive electrode sheet, the negative electrode sheet and the separator include: compounding the negative electrode unit sheet on the upper side of the upper separator; compounding the positive electrode unit sheet between the two layers of separators; and fixing the R angle support structure at the R angle position of the separator before winding includes: hot-melting and fixing the two R angle support structures at the preset positions of the upper separator, so that the width of the two R angle support structures is equal to the width of the negative electrode unit sheet. This compounding and fixing method ensures the stability of the R angle support structure and the matching with the electrode sheet, while simplifying the winding process and improving production efficiency.

[0016] According to another aspect of the present invention, a lithium electronic battery is provided, comprising a wound lithium ion battery core, wherein the wound lithium ion battery core is the wound lithium ion battery core described above. The lithium electronic battery has all the advantages of the wound lithium ion battery core described above.

[0017] By applying the technical solution of the present invention, the wound lithium-ion battery roll core includes: a positive electrode sheet, including a discontinuous positive electrode unit sheet and a continuous positive electrode sheet; a negative electrode sheet, including a discontinuous negative electrode unit sheet and a continuous negative electrode sheet; a diaphragm, which is arranged between the positive electrode sheet and the negative electrode sheet to form a gap; two R-angle support structures, the continuous positive electrode sheet is wrapped around the outer periphery of the positive electrode unit sheet, and the continuous negative electrode sheet is wrapped around the outer periphery of the negative electrode unit sheet, the two R-angle support structures are located at the two R corners of the innermost layer of the battery roll core, at least part of the positive electrode unit sheet and at least part of the negative electrode unit sheet are stacked between the two R-angle support structures, which effectively prevents the inner electrode sheet from cracking and falling off at the bending point of the R corner, and accelerates the infiltration of the electrolyte. By introducing an R-corner support structure at the R-corner bend of the inner layer of the winding core, the R-corner support structure can be used to form support at the inner bending position of the positive electrode sheet and the negative electrode sheet, thereby increasing the bending radius of the positive electrode sheet and the negative electrode sheet at the inner bending position, and avoiding the problem of cracking and falling of the positive electrode sheet and the negative electrode sheet in the inner circle R corner due to too small bending radius, thereby improving the risk of internal short circuit or lithium plating of the battery cell and improving the safety and stability of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0019] Figure 1 is a schematic structural diagram of a wound lithium-ion battery core according to an embodiment of the present invention;

[0020] Figure 2 1 is a schematic structural diagram of a wound lithium-ion battery core before winding according to an embodiment of the present invention;

[0021] Figure 3 is a structural schematic diagram of an R-angle support structure of a wound lithium-ion battery core according to an embodiment of the present invention; and

[0022] Figure 4 It is a flow chart of a method for manufacturing a wound lithium-ion battery core according to an embodiment of the present invention.

[0023] The above drawings include the following reference numerals:

[0024] 1. Negative electrode unit cell; 2. Positive electrode unit cell; 3. Diaphragm; 4. R-angle support structure; 5. Continuous negative electrode sheet; 6. Continuous positive electrode sheet; 7. Holes; 8. Flat plate segment; 9. Arc plate segment. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] See also Figures 1 to 3 As shown, according to an embodiment of the present invention, a wound lithium-ion battery core includes: a positive electrode sheet, including a discontinuous positive electrode unit sheet 2 and a continuous positive electrode sheet 6; a negative electrode sheet, including a discontinuous negative electrode unit sheet 1 and a continuous negative electrode sheet 5; a separator 3, arranged between the positive electrode sheet and the negative electrode sheet to form a gap; two R-angle support structures 4, the continuous positive electrode sheet 6 is wrapped around the outer periphery of the positive electrode unit sheet 2, and the continuous negative electrode sheet 5 is wrapped around the outer periphery of the negative electrode unit sheet 1, the two R-angle support structures 4 are located at the two R corners of the innermost layer of the battery core, and at least part of the positive electrode unit sheet 2 and at least part of the negative electrode unit sheet 1 are stacked between the two R-angle support structures 4.

[0027] The two R-corner support structures 4 are located at the two R-corners of the innermost layer of the battery roll core, and can provide additional support for the R-corners of the innermost roll core. The introduction of the R-corner support structure 4 solves the problem of cracking and falling of the pole piece caused by the small bending radius at the R-corner of the inner layer of the roll core. Since the pole piece is almost folded in half at the R-corner, the inner pole piece of the traditional roll core is prone to form a stress concentration point at this position, causing material fatigue and cracks, and then causing safety problems such as short circuit or lithium deposition. The setting of the R-corner support structure 4 greatly alleviates this problem, reduces the bending stress of the inner pole piece at the R-corner, improves the risk of short circuit or lithium deposition inside the battery cell, and improves the safety and stability of the battery.

[0028] The positive electrode sheet is divided into a discontinuous positive electrode unit sheet 2 and a continuous positive electrode sheet 6, and the negative electrode sheet is divided into a discontinuous negative electrode unit sheet 1 and a continuous negative electrode sheet 5. This design ensures that at the beginning of winding, the discontinuous positive electrode unit sheet 2 and the negative electrode unit sheet 1 are wound first. Through the guidance of the R-angle support structure 4, these units will not form excessive bends at the R angle, avoiding cracking and falling of materials. At least part of the positive electrode unit sheet 2 and at least part of the negative electrode unit sheet 1 are stacked between the two R-angle support structures 4, which can ensure the support effect of the R-angle support structure 4 on the inner layer electrode sheet at the R angle position, avoiding the inner layer electrode sheet from bending at the R angle. As the winding proceeds, the continuous positive electrode sheet 6 and the continuous negative electrode sheet 5 begin to enter the sheet, and they are wound around the outside of the R-angle support structure 4, further enhancing the support effect at the R angle, ensuring that in the subsequent continuous winding, the electrode sheet material can still maintain good integrity, reduce internal defects, and improve the overall performance of the battery.

[0029] The method of the present invention simplifies the processing process of the inner layer pole piece, avoids the common quality problems in the traditional winding process, such as cracking and material falling of the inner layer pole piece, thereby improving the production yield.

[0030] In one embodiment, the R-angle support structure 4 is provided with a central hole penetrating at least one end along the length direction, and a hole 7 is opened on the hole wall of the central hole.

[0031] The R-angle support structure 4 is hollowed out in the middle to form a central hole, and a hole 7 is opened on the side. This design not only reduces the weight of the R-angle support structure, but also increases its air permeability and electrolyte permeability. The presence of hole 7 accelerates the infiltration speed of the electrolyte, which is especially important for large-capacity battery rolls. It can ensure that the electrolyte evenly and quickly infiltrates the entire roll, thereby improving the performance and consistency of the battery, while shortening the production time and improving production efficiency. The center hole penetrates at least one end of the R-angle support structure 4 along the length direction, so that the center hole can be connected to the injection hole through the penetrated end, which is convenient for injecting liquid into the center hole through the injection hole, thereby utilizing hole 7 for electrolyte infiltration.

[0032] In one embodiment, the R-angle support structure 4 includes a flat plate segment 8 and an arcuate plate segment 9 , wherein the arcuate plate segment 9 is fixedly connected to the flat plate segment 8 and is located on a side of the flat plate segment 8 away from the positive electrode unit sheet 2 and the negative electrode unit sheet 1 .

[0033] The R-angle support structure 4 is designed as a composite structure including a flat plate segment 8 and an arc-shaped plate segment 9. The fixed connection between the flat plate segment 8 and the arc-shaped plate segment 9 ensures the integrity and stability of the structure. The arc-shaped plate segment 9 is located on the side of the flat plate segment 8 away from the positive electrode unit sheet 2 and the negative electrode unit sheet 1, which helps to form a larger bending radius at the bending position of the electrode sheet during the winding process, thereby avoiding excessive bending and possible cracking of the electrode sheet at the R angle. The negative electrode unit sheet 1 and the positive electrode unit sheet 2 are located between the two flat plate segments 8. The negative electrode unit sheet 1 can be installed and positioned by the flat plate segment 8, so that the positive electrode unit sheet 2 and the negative electrode unit sheet 1 can cooperate with the R-angle support structure 4 on both sides to form a structure similar to the bending of the electrode sheet, thereby ensuring the support effect of the positive electrode sheet and the negative electrode sheet located outside the R-angle support structure 4 at the bending position, and improving the structural stability and reliability of the battery roll core.

[0034] The R-angle support structure 4 adopts a structure combining a flat plate segment 8 and an arc-shaped plate segment 9, which is convenient for forming a center hole between the flat plate segment 8 and the arc-shaped plate segment 9, and is also convenient for setting holes 7 on the flat plate segment 8 and the arc-shaped plate segment 9 along the wall thickness direction. The holes 7 are connected to the center hole, so that the electrolyte can flow from each hole 7 to the inner and outer electrodes through the center hole, effectively promoting the diffusion of the electrolyte inside the winding core, increasing the infiltration speed, and thus improving the performance and production efficiency of the lithium-ion battery. The shape and position of the arc-shaped plate segment 9 ensure that after hot pressing and finalization, there will be no cracking and falling of the pole piece at the R corner of the winding core, further improving the safety and reliability of the battery.

[0035] In one embodiment, the flat plate segment 8 and the arc-shaped plate segment 9 are an integrally formed structure, and the outer peripheral surface includes a plane and an arc surface, and both ends of the arc surface are connected to the plane to form the outer contour of the R-angle support structure 4.

[0036] In one embodiment, the length of the R-angle support structure 4 is the same as the length of the negative electrode unit sheet 1, the thickness is equal to the sum of the thicknesses of the positive electrode unit sheet 2 and the negative electrode unit sheet 1, and the width of the diaphragm 3 between the innermost adjacent negative electrode unit sheets 1 is equal to the outer circumferential arc length of the arc-shaped plate segment.

[0037] The R-angle support structure 4 is embedded in the R-angle bend of the inner layer of the winding core, and can provide sufficient support to avoid stress concentration in the positive electrode unit sheet 2 and the negative electrode unit sheet 1 in this area, thereby preventing cracking and falling of the material. The length of the R-angle support structure 4 is consistent with the length of the negative electrode unit sheet 1, ensuring that it can cover the entire length of the negative electrode unit sheet 1, and the thickness is equal to the sum of the thickness of the positive electrode unit sheet 2 and the negative electrode unit sheet 1. This design enables the R-angle support structure 4 to form a whole with the positive electrode unit sheet 2 and the negative electrode unit sheet 1, so that all the positive electrode unit sheets 2 and the negative electrode unit sheets 1 are located between the two R-angle support structures 4, avoiding the positive electrode unit sheet 2 and the negative electrode unit sheet 1 from exceeding the support range of the R-angle support structure 4, causing adverse effects on the winding of the continuous positive electrode sheet 6 and the continuous negative electrode sheet 5, and enhancing the stability of the winding core structure.

[0038] In this embodiment, the length direction of the R-angle support structure 4 is consistent with the length direction of the negative electrode unit sheet 1 , both extend along the plane of the separator 3 , and are perpendicular to the winding direction of the negative electrode sheet.

[0039] The width of the diaphragm 3 located between the innermost adjacent negative electrode unit sheets 1 and cooperating with the two R-angle support structures 4 is equal to the outer circumferential arc length of the arc-shaped plate segment 9. During the winding process, the diaphragm 3 can be accurately positioned around the arc-shaped plate segment 9 of the R-angle support structure 4 to form a natural bend, and can ensure that the positive electrode unit sheet 2 and the negative electrode unit sheet 1 are completely located within the two R-angle support structures 4, thereby avoiding interference between the positive electrode unit sheet 2 and the negative electrode unit sheet 1 and the R-angle support structure 4 during the winding process, and at the same time ensuring the tensioning effect of the diaphragm 3, so that the diaphragm 3 can be fully unfolded, thereby further improving the molding quality of the battery roll core.

[0040] Along the winding direction, the width of the separator 3 between two adjacent negative electrode unit sheets 1 gradually increases, so as to adapt to the change in arc length caused by the increase in separator thickness. Specifically, the separator 3 that fits the two R-angle support structures 4 forms a first layer of wrapped separator, and the width of the first layer of wrapped separator is equal to the outer peripheral arc length of the arc-shaped plate segment 9 of the R-angle support structure 4. The separator 3 located outside the first layer of wrapped separator and fits the first layer of wrapped separator forms a second layer of wrapped separator, and the width of the second layer of wrapped separator is equal to the outer peripheral arc length of the first layer of wrapped separator. By analogy, the larger the number of layers, the larger the width of the separator 3 between two adjacent negative electrode unit sheets 1, so as to adapt to the increase in arc length caused by the increase in separator thickness.

[0041] In one embodiment, the total thickness of the positive electrode unit sheet 2 and the negative electrode unit sheet 1 may also be slightly smaller or larger than the thickness of the R-angle support structure 4 in the thickness direction of the negative electrode sheet, where the size difference is the thickness of 1 to 2 layers of the negative electrode unit sheet 1.

[0042] In one embodiment, the battery filling port is aligned with the center hole of the R-angle support structure 4 and is connected to the center hole.

[0043] Since the R-angle support structure 4 has a hole structure in the middle, the electrolyte can directly penetrate into the core through the center hole without having to rely on the electrolyte to slowly diffuse along the edge of the electrode. This greatly shortens the time for the electrolyte to completely soak the core and improves the soaking efficiency.

[0044] The holes 7 of the R-angle support structure 4 help the electrolyte to be evenly distributed inside the coil, avoiding the accumulation of electrolyte in some areas and the lack of electrolyte in some areas, thereby ensuring the consistency and stability of the battery cell.

[0045] In one embodiment, the material of the R-angle supporting structure 4 includes one or more of PP, PE, and PET.

[0046] PP, PE, and PET materials have good chemical stability, can resist the erosion of the electrolyte inside the battery, maintain the integrity and stability of their structure, and thus ensure that the R-angle support structure continues to function throughout the battery life. These materials are heat-resistant to a certain extent, can withstand the heat generated by the battery during the charging and discharging process, are not easy to deform or melt, and ensure the reliability of the structure under high temperature conditions. PP, PE, and PET are all good insulating materials that can effectively prevent the positive and negative pole pieces from short-circuiting at the R angle, improve the safety of the battery, and are lightweight. They will not significantly increase the overall weight of the battery, which helps to maintain the lightweight design of the battery. The material cost is relatively low, easy to process, suitable for large-scale production, and conducive to reducing the manufacturing cost of the battery. They are easy to process into the required shape, such as the center hole in the R-angle support structure and the hole 7 on the side, to achieve its design function.

[0047] In one embodiment, the number of positive electrode unit sheets 2 and the number of negative electrode unit sheets 1 are 2 to 10. Two layers of discontinuous negative electrode unit sheets are one circle, and generally the inner layer cracking occurs in 1-5 circles, so the number of discontinuous negative electrode unit sheets 1 is 2-10. Different cells adjust the number of discontinuous negative electrode unit sheets 1 according to the number of inner layer cracking circles.

[0048] The width of the positive electrode unit sheet 2 is 3 mm to 4 mm smaller than that of the negative electrode unit sheet 1 , so that the negative electrode unit sheet 1 can cover the positive electrode unit sheet 2 during the winding process.

[0049] See also Figure 4As shown, according to an embodiment of the present invention, the method for manufacturing the wound lithium-ion battery core includes:

[0050] Prepare positive electrode sheets, negative electrode sheets and separators, wherein the positive electrode sheets include a positive electrode unit sheet 2 and a continuous positive electrode sheet 6, and the negative electrode sheets include a negative electrode unit sheet 1 and a continuous negative electrode sheet 5;

[0051] Prepare R angle support structure 4;

[0052] Before winding, the R-angle support structure 4 is fixed at the R-angle position of the diaphragm 3;

[0053] Winding the positive electrode unit sheet 2 and the negative electrode unit sheet 1, so that the positive electrode unit sheet 2 and the negative electrode unit sheet 1 are stacked between two R-angle support structures 4, and the separator 3 between adjacent positive electrode unit sheets 2 and the separator 3 between adjacent negative electrode unit sheets 1 are coated outside the R-angle support structure 4;

[0054] Continue to wind the continuous positive electrode sheet 6 and the continuous negative electrode sheet 5;

[0055] Heat pressing.

[0056] Due to the introduction of the R-angle support structure 4, the stress of the inner electrode at the R-angle bend is effectively relieved, avoiding the problem of cracking and falling of the positive and negative electrode sheets at the bend, and significantly reducing the risk of internal short circuit or lithium deposition in the battery cell.

[0057] The positive electrode unit sheet 2 and the negative electrode unit sheet 1 are located between the R-angle support structures 4 on both sides, which helps to avoid excessive bending of the electrode sheet at the R angle, thereby preventing cracking and material falling problems. The diaphragm 3 between adjacent positive electrode unit sheets 2 and the diaphragm 3 between adjacent negative electrode unit sheets 1 are coated outside the R-angle support structure 4, which can ensure the stability of the R-angle support structure 4 during the winding process, and ensure the continuity and integrity of the battery cell winding structure. At the same time, the presence of the diaphragm provides additional insulation and protection to prevent the positive electrode sheet and the negative electrode sheet from directly contacting each other and causing a short circuit.

[0058] In one embodiment, before the step of winding the positive electrode unit sheet 2 and the negative electrode unit sheet 1, the method further includes:

[0059] The separator 3 is pre-rolled to position the R-corner support structure 4 at the R corners on both sides of the innermost layer of the winding core.

[0060] The step of pre-rolling the diaphragm to position the R-corner support structure 4 at the R-corners on both sides of the innermost layer of the winding core can ensure that the R-corner support structure 4 is accurately placed at the required position, namely, at the R-corners on both sides of the innermost layer of the winding core.

[0061] When the pre-rolling separator step is performed, the separator with the R-angle support structure 4 is pre-rolled one or more times to ensure that the R-angle support structure 4 is fixed in the correct position at the beginning of winding. Subsequently, the discontinuous positive electrode unit sheet 2 and the negative electrode unit sheet 1 are compounded in the appropriate position of the separator 3 and start winding. This action of pre-rolling the separator ensures the stability of the R-angle support structure 4 during the entire winding process, avoiding the problem of folding and cracking of the electrode sheet due to inaccurate positioning during the winding process.

[0062] In one embodiment, the separator 3 is pre-wound once during winding so that the R-corner support structure is located at the R-corners on both sides of the innermost layer of the winding core, and then the discontinuous positive electrode unit sheet 2 and the negative electrode unit sheet 1 are wound, and then the continuous negative electrode sheet 5 and the continuous positive electrode sheet 6 are inserted and wound until the winding is completed.

[0063] In one embodiment, the steps of preparing the positive electrode sheet, the negative electrode sheet and the separator include: compounding the negative electrode unit sheet 1 on the upper side of the upper separator; compounding the positive electrode unit sheet 2 between the two layers of separators; the step of fixing the R-angle support structure 4 at the R-angle position of the separator 3 before winding includes: hot-melting and fixing the two R-angle support structures 4 at the preset positions of the upper separator, so that the width of the two R-angle support structures 4 is equal to the width of the negative electrode unit sheet 1.

[0064] In this embodiment, the diaphragm is two layers, namely, an upper diaphragm located on the upper side and a lower diaphragm located on the lower side, the upper diaphragm and the lower diaphragm are spaced apart, the negative electrode unit sheet 1 is composited on the upper side of the upper diaphragm, the positive electrode unit sheet 2 is composited between the lower side of the upper diaphragm and the upper side of the lower diaphragm, and two R angle support structures 4 are fixed on the upper diaphragm and spaced apart. Through the above structure, the insulation spacing between the positive electrode unit sheet 2 and the negative electrode unit sheet 1 can be achieved.

[0065] The R-angle support structure 4 is located at the R-angles on both sides of the innermost layer of the winding core. Since its thickness is equal to the sum of the thickness of the discontinuous positive and negative electrode sheets, it can significantly increase the bending radius at the R-angle, thereby avoiding cracks or material loss due to excessive bending of the inner electrode sheets at the R-angle position, and effectively reducing the risk of short circuit or lithium deposition inside the battery cell. Fixing the R-angle support structure 4 by hot melting can not only ensure its position accuracy during the winding process, but also ensure the stability of the structure, avoiding displacement of the R-angle support structure 4 during subsequent processing such as pressurization and shaping, which affects battery performance.

[0066] According to an embodiment of the present invention, a lithium electronic battery comprises a wound lithium ion battery core, which is the wound lithium ion battery core described above. The lithium electronic battery has all the advantages of the wound lithium ion battery core described above.

[0067] The wound lithium-ion battery core of the present invention has the following technical effects:

[0068] By introducing the R-angle support structure at the R-angle bend of the inner layer of the winding core, the problem of cracking and falling of the inner electrode due to the too small bending radius at the bend is solved, the risk of internal short circuit or lithium precipitation of the battery cell is avoided, and the safety and stability of the battery are improved. At the same time, the hole design of the R-angle support structure accelerates the infiltration of the electrolyte, improves the electrochemical performance and production efficiency of the battery, and is of great significance for the production and application of large-capacity batteries. The selection of materials and precise matching of sizes enable the R-angle support structure to adapt to the internal environment of the battery and ensure the long-term stable operation of the battery. The step of pre-rolling the diaphragm further optimizes the positioning of the R-angle support structure, avoids errors in the production process, and improves the quality consistency of the battery. Overall, this technology effectively improves the structural design and production process of wound lithium-ion batteries, and improves the performance and production efficiency of the battery.

[0069] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0070] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A wound lithium-ion battery core, characterized in that: include: A positive electrode sheet, comprising a discontinuous positive electrode unit sheet (2) and a continuous positive electrode sheet (6); A negative electrode sheet, comprising a discontinuous negative electrode unit sheet (1) and a continuous negative electrode sheet (5); A diaphragm (3) is arranged between the positive electrode sheet and the negative electrode sheet to form a gap; Two R-angle support structures (4), the continuous positive electrode sheet (6) is wrapped around the outer periphery of the positive electrode unit sheet (2), the continuous negative electrode sheet (5) is wrapped around the outer periphery of the negative electrode unit sheet (1), the two R-angle support structures (4) are located at the two R corners of the innermost layer of the battery roll core, and at least part of the positive electrode unit sheet (2) and at least part of the negative electrode unit sheet (1) are stacked between the two R-angle support structures (4).

2. The wound lithium-ion battery core according to claim 1, characterized in that: The R-angle support structure (4) is provided with a central hole penetrating at least one end along the length direction, and a hole (7) is opened on the hole wall of the central hole.

3. The wound lithium-ion battery core according to claim 1, characterized in that: The R-angle support structure (4) comprises a flat plate segment (8) and an arc-shaped plate segment (9), wherein the arc-shaped plate segment (8) is fixedly connected to the flat plate segment (8) and is located on a side of the flat plate segment (8) away from the positive electrode unit sheet (2) and the negative electrode unit sheet (1).

4. The wound lithium-ion battery core according to claim 3, characterized in that: The length of the R-angle support structure (4) is the same as that of the negative electrode unit sheet (1), and the thickness is equal to the sum of the thicknesses of the positive electrode unit sheet (2) and the negative electrode unit sheet (1). The width of the diaphragm (3) located between the innermost adjacent negative electrode unit sheets (1) is equal to the outer circumferential arc length of the arc-shaped plate segment.

5. The wound lithium-ion battery core according to claim 2, characterized in that: The battery liquid filling port is arranged to align with the central hole of the R-angle supporting structure (4) and is communicated with the central hole.

6. The wound lithium-ion battery core according to claim 1, characterized in that: The material of the R-angle support structure (4) includes one or more of PP, PE, and PET.

7. The wound lithium-ion battery core according to claim 1, characterized in that: The number of the positive electrode unit sheets (2) and the number of the negative electrode unit sheets (1) are 2 to 10; and / or the width of the positive electrode unit sheet (2) is 3 mm to 4 mm smaller than the width of the negative electrode unit sheet (1).

8. A method for manufacturing a wound lithium-ion battery core according to any one of claims 1 to 7, characterized in that: include: Prepare a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet comprises a positive electrode unit sheet (2) and a continuous positive electrode sheet (6), and the negative electrode sheet comprises a negative electrode unit sheet (1) and a continuous negative electrode sheet (5); Preparing an R-angle support structure (4); Before winding, the R-angle support structure (4) is fixed at the R-angle position of the diaphragm (3); Winding the positive electrode unit sheet (2) and the negative electrode unit sheet (1) such that the positive electrode unit sheet (2) and the negative electrode unit sheet (1) are stacked between two R-angle support structures (4), and the separator (3) between adjacent positive electrode unit sheets (2) and the separator (3) between adjacent negative electrode unit sheets (1) are wrapped outside the R-angle support structure (4); Continue to wind the continuous positive electrode sheet (6) and the continuous negative electrode sheet (5); Heat pressing.

9. The manufacturing method according to claim 8, characterized in that: Before the step of winding the positive electrode unit sheet (2) and the negative electrode unit sheet (1), the method further includes: The pre-rolled diaphragm (3) is used to position the R-corner support structure (4) at the R-corners on both sides of the innermost layer of the winding core.

10. The manufacturing method according to claim 8, characterized in that: The steps of preparing the positive electrode sheet, the negative electrode sheet and the separator include: Compounding the negative electrode unit sheet (1) on the upper side of the upper separator; Compounding the positive electrode unit sheet (2) between two layers of separators; The step of fixing the R-angle support structure (4) at the R-angle position of the diaphragm (3) before winding comprises: The two R-angle support structures (4) are fixed at preset positions of the upper separator by hot melting, so that the width of the two R-angle support structures (4) is equal to the width of the negative electrode unit sheet (1).

11. A lithium electronic battery, comprising a wound lithium ion battery core, characterized in that: The wound lithium-ion battery core is the wound lithium-ion battery core according to any one of claims 1 to 7.

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