Roll core and battery

Abstract

The invention discloses a roll core and a battery, the roll core comprises a positive plate, a negative plate and a diaphragm, the positive plate, the diaphragm and the negative plate are wound from the head end to the tail end along the winding direction to form the roll core; the winding core is divided into a first winding area and a second winding area; the positive tab and the negative tab are positioned in the first winding area; the first anode active layer edge, the second anode active layer edge, the first adhesive paper far away from one end of the anode lug, the second adhesive paper far away from one end of the anode lug, the first cathode active layer close to one end of the first cathode blank area, the second cathode active layer close to one end of the second cathode blank area, and the third adhesive paper far away from one end of the cathode lug; one end, far away from the negative tab, of the fourth gummed paper is positioned in the second winding area, so that the positive tab / negative tab, the edge of the active layer and the edge of the gummed paper are uniformly distributed in the circumferential direction of the winding core, and a larger step is avoided, so that the risk of breaking the positive plate / negative plate is reduced, and the overall quality and the service life of the battery are improved.

Description

Technical Field

[0001] The present invention relates to the field of batteries, and in particular to a winding core and a battery. Background Art

[0002] In the existing OOT (Out-Out-Tab) structure of the winding core, the positive and negative tabs are welded to the tail of the pole piece. In order to prevent the occurrence of lithium plating, the negative electrode sheet needs to completely wrap the positive electrode sheet; but in order to avoid material waste, the negative electrode sheet is usually only slightly larger than the positive electrode sheet. This compact structural design causes the welding edges of the pole tabs, the edges of the positive and negative electrode sheet areas, and the edges of the adhesive tape to be densely stacked in the same semicircular area of ​​the winding core, forming a large height difference in the radial direction of the winding core, the so-called "step". During the battery cycle charge and discharge process, due to the expansion and contraction of the positive and negative electrode materials, it is very easy to produce fragmentation at the step. This will not only cause abnormalities in the charging and discharging process, but may also cause more serious safety problems, such as internal short circuits and even thermal runaway, which will seriously affect the overall quality and service life of the battery. Summary of the invention

[0003] The embodiments of the present invention provide a winding core, a lithium-ion battery and a battery to solve the problem that the winding core is easily broken at the step.

[0004] Specifically, the present invention provides a winding core, comprising a positive electrode sheet, a negative electrode sheet and a separator, wherein the positive electrode sheet, the separator and the negative electrode sheet are wound from a head end to a tail end along a winding direction to form the winding core; The positive electrode sheet comprises a positive electrode current collector and a first positive electrode active layer and a second positive electrode active layer arranged on both sides of the positive electrode current collector; a first positive electrode blank area and a second positive electrode blank area are respectively arranged on both sides of the tail end of the positive electrode current collector; the second positive electrode blank area is connected to a positive electrode ear at one end of the first positive electrode blank area away from the second positive electrode active layer, a first adhesive tape is pasted on the first positive electrode blank area, and the two ends of the first adhesive tape extend to the first positive electrode active layer and the positive electrode ear respectively; a second adhesive tape is pasted on the second positive electrode blank area, and the two ends of the second adhesive tape extend to the second positive electrode active layer and the edge of the second positive electrode blank area respectively; the winding core has a first reference line along the center of the winding core pointing to the side of the positive electrode ear close to the first positive electrode active layer; The negative electrode sheet comprises a negative electrode current collector and a first negative electrode active layer and a second negative electrode active layer arranged on both sides of the negative electrode current collector; a first negative electrode blank area and a second negative electrode blank area are respectively arranged on both sides of the tail end of the negative electrode current collector; an end of the second negative electrode blank area away from the second negative electrode active layer is connected to a negative electrode ear, a third adhesive tape is pasted on the first negative electrode blank area, and the two ends of the third adhesive tape extend to the first negative electrode active layer and the negative electrode ear respectively; a fourth adhesive tape is pasted on the second negative electrode blank area, and the two ends of the fourth adhesive tape extend to the second negative electrode active layer and the edge of the second negative electrode blank area respectively; the winding core also has a second reference line along the center of the winding core pointing to the side of the negative electrode ear away from the first negative electrode active layer; the first reference line and the second reference line divide the winding core into a first winding area and a second winding area; the positive electrode ear and the negative electrode ear are located in the first winding area; One end of the first positive electrode active layer close to the first positive electrode blank area, one end of the second positive electrode active layer close to the second positive electrode blank area, one end of the first adhesive tape away from the positive electrode ear, one end of the second adhesive tape away from the positive electrode ear, one end of the first negative electrode active layer close to the first negative electrode blank area, one end of the second negative electrode active layer close to the second negative electrode blank area, one end of the third adhesive tape away from the negative electrode ear, and one end of the fourth adhesive tape away from the negative electrode ear are located in the second winding area.

[0005] Optionally, the central angle of the first winding area does not exceed 180°.

[0006] Optionally, the length of the first negative electrode active layer is greater than the length of the second negative electrode active layer; The winding core has a third reference line along the center of the winding core pointing to the side of the first negative electrode active layer close to the first negative electrode blank area; the third reference line is located in the second winding area; Along the winding direction of the winding core, the arc length between the positive electrode ear and the third reference line is not less than 3 mm.

[0007] Optionally, the length of the first positive electrode active layer is greater than the length of the second positive electrode active layer; The winding core has a fourth reference line along the center of the winding core pointing to the side of the second adhesive tape away from the positive electrode ear; the fourth reference line is located in the second winding area; Along the winding direction of the winding core, the arc length between the negative electrode ear and the fourth reference line is not less than 3 mm.

[0008] Optionally, the second winding area includes a first sub-area and a second sub-area; a boundary line between the first sub-area and the second sub-area extends along the radial direction of the winding core, and a central angle between the boundary line and the first reference line is equal to a central angle between the boundary line and the second reference line; Parts of one end of the first positive electrode active layer close to the first positive electrode blank area, one end of the second positive electrode active layer close to the second positive electrode blank area, one end of the first adhesive tape away from the positive electrode ear, one end of the second adhesive tape away from the positive electrode ear, one end of the first negative electrode active layer close to the first negative electrode blank area, one end of the second negative electrode active layer close to the second negative electrode blank area, one end of the third adhesive tape away from the negative electrode ear, and one end of the fourth adhesive tape away from the negative electrode ear are located in the first sub-region, and the rest are located in the second sub-region.

[0009] Optionally, one end of the first negative electrode active layer close to the first negative electrode blank area, one end of the second negative electrode active layer close to the second negative electrode blank area, one end of the third adhesive tape away from the negative electrode ear, and one end of the fourth adhesive tape away from the negative electrode ear are located in the first sub-region; One end of the first positive electrode active layer close to the first positive electrode blank area, one end of the second positive electrode active layer close to the second positive electrode blank area, one end of the first adhesive tape away from the positive electrode ear, and one end of the second adhesive tape away from the positive electrode ear are located in the second sub-area.

[0010] Optionally, at the tail end of the winding core, the negative electrode sheet extends beyond the positive electrode sheet along the winding direction.

[0011] Optionally, the ratio of the length of the first positive electrode blank area to the diameter of the core is 0-2 / 3, and the ratio of the length of the second positive electrode blank area to the diameter of the core is 0-1; the ratio of the length of the first negative electrode blank area to the diameter of the core is 0-1, and the ratio of the length of the second negative electrode blank area to the diameter of the core is 0-1.

[0012] The present invention further provides a battery, comprising a shell and a winding core as described in any one of the above items, wherein the winding core is arranged in the shell.

[0013] The beneficial effects of the present invention are: In the winding core and the battery provided by the present invention, since the first reference line and the second reference line divide the winding core into a first winding area and a second winding area, the positive electrode ear and the negative electrode ear are located in the first winding area, and the end of the first positive electrode active layer close to the first positive electrode blank area, the end of the second positive electrode active layer close to the second positive electrode blank area, the end of the first adhesive tape away from the positive electrode ear, the end of the second adhesive tape away from the positive electrode ear, the end of the first negative electrode active layer close to the first negative electrode blank area, the end of the second negative electrode active layer close to the second negative electrode blank area, the end of the third adhesive tape away from the negative electrode ear, and the end of the fourth adhesive tape away from the negative electrode ear are located in the second winding area, so that the positive / negative electrode ears, the edges of the active layers (including the first positive electrode active layer, the second positive electrode active layer, the first negative electrode active layer, and the second negative electrode active layer), and the edges of the adhesive tapes (including the first adhesive tape, the second adhesive tape, the third adhesive tape, and the fourth adhesive tape) are evenly distributed on the circumference of the winding core to avoid the generation of large steps, thereby reducing the risk of positive / negative electrode fragments and improving the overall quality and service life of the battery.

[0014] Furthermore, such an arrangement makes it possible to avoid the existence of an active layer edge between the positive and negative electrode ears, thereby avoiding a large drop when the active layer is wound around the positive / negative electrode ears, further reducing the risk of positive / negative electrode fragmentation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0016] Figure 1 is a schematic structural diagram of a winding core in one embodiment of the present invention; Figure 2 is a schematic structural diagram of a positive electrode sheet in one embodiment of the present invention; Figure 3 Schematic diagram of the structure of a negative electrode sheet in one embodiment of the present invention.

[0017] In the figure: 10, winding core, 100, positive electrode sheet, 110, positive electrode collector, 111, first positive electrode blank area, 112, second positive electrode blank area, 120, first positive electrode active layer, 130, second positive electrode active layer, 200, negative electrode sheet, 210, negative electrode collector, 211, first negative electrode blank area, 212, second negative electrode blank area, 220, first negative electrode active layer, 230, second negative electrode active layer, 300, separator, 410, first adhesive tape, 420, second adhesive tape, 430, third adhesive tape, 440, fourth adhesive tape, 450, fifth adhesive tape, 510, first reference line, 520, second reference line, 530, third reference line, 540, fourth reference line, 610, positive electrode ear, 620, negative electrode ear. DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] In the description of the present invention, it should be understood that the terms "longitudinal", "radial", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0020] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be glue injection inside two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] Figure 1 is a schematic structural diagram of a winding core in one embodiment of the present invention, such as Figure 1 As shown, and refer to Figures 2 to 3The embodiment of the present invention provides a winding core, comprising a positive electrode sheet 100, a negative electrode sheet 200 and a separator 300, wherein the positive electrode sheet 100, the separator 300 and the negative electrode sheet 200 are wound from the head end to the tail end along the winding direction to form the winding core 10. Figure 2 As shown, the positive electrode sheet 100 includes a positive electrode collector 110 and a first positive electrode active layer 120 and a second positive electrode active layer 130 arranged on both sides of the positive electrode collector 110. A first positive electrode blank area 111 and a second positive electrode blank area 112 are respectively provided on both sides of the tail end of the positive electrode collector 110. The end of the second positive electrode blank area 112 away from the second positive electrode active layer 130 is connected to a positive electrode ear 610, and a first adhesive tape 410 is pasted on the first positive electrode blank area 111, and the two ends of the first adhesive tape 410 extend to the first positive electrode active layer 120 and the positive electrode ear 610 respectively. A second adhesive tape 420 is pasted on the second positive electrode blank area 112, and the two ends of the second adhesive tape 420 extend to the second positive electrode active layer 130 and the edge of the second positive electrode blank area 112 respectively; the winding core 10 has a first reference line 510 along the center of the winding core 10 pointing to the side of the positive electrode ear 610 close to the first positive electrode active layer 120. As shown Figure 3As shown, the negative electrode sheet 200 includes a negative electrode current collector 210 and a first negative electrode active layer 220 and a second negative electrode active layer 230 disposed on both sides of the negative electrode current collector 210. A first negative electrode blank area 211 and a second negative electrode blank area 212 are respectively disposed on both sides of the tail end of the negative electrode current collector 210. A negative electrode ear 620 is connected to one end of the second negative electrode blank area 212 away from the second negative electrode active layer 230, and a third adhesive tape 430 is pasted on the first negative electrode blank area 211, and the two ends of the third adhesive tape 430 extend to the first negative electrode active layer 220 and the negative electrode ear 620 respectively. A fourth adhesive tape 440 is pasted on the second negative electrode blank area 212, and the two ends of the fourth adhesive tape 440 extend to the second negative electrode active layer 230 and the edge of the second negative electrode blank area 212 respectively. The winding core 10 also has a second reference line 520 along the center of the winding core 10 pointing to the negative electrode tab 620 away from the first negative electrode active layer 220; the first reference line 510 and the second reference line 520 divide the winding core 10 into a first winding area and a second winding area. The positive electrode tab 610 and the negative electrode tab 620 are located in the first winding area. The first positive electrode active layer 120 is close to one end of the first positive electrode blank area 111, the second positive electrode active layer 130 is close to one end of the second positive electrode blank area 112, the first adhesive tape 410 is away from one end of the positive electrode ear 610, the second adhesive tape 420 is away from one end of the positive electrode ear 610, the first negative electrode active layer 220 is close to one end of the first negative electrode blank area 211, the second negative electrode active layer 230 is close to one end of the second negative electrode blank area 212, the third adhesive tape 430 is away from one end of the negative electrode ear 620, and the fourth adhesive tape 440 is away from one end of the negative electrode ear 620 are located in the second winding area.

[0022] In the embodiment of the present invention, since the first reference line 510 and the second reference line 520 divide the winding core 10 into a first winding area and a second winding area, the positive electrode ear 610 and the negative electrode ear 620 are located in the first winding area, the first positive electrode active layer 120 is close to one end of the first positive electrode blank area 111, the second positive electrode active layer 130 is close to one end of the second positive electrode blank area 112, the first adhesive tape 410 is away from one end of the positive electrode ear 610, the second adhesive tape 420 is away from one end of the positive electrode ear 610, the first negative electrode active layer 220 is close to one end of the first negative electrode blank area 211, and the second negative electrode active layer 230 is close to the second negative electrode blank area 212. One end of the pole blank area 212, one end of the third adhesive tape 430 away from the negative electrode ear 620, and one end of the fourth adhesive tape 440 away from the negative electrode ear 620 are located in the second winding area, so that the positive / negative electrode ears 620, the edges of the active layers (including the first positive electrode active layer 120, the second positive electrode active layer 130, the first negative electrode active layer 220, and the second negative electrode active layer 230), and the edges of the adhesive tapes (including the first adhesive tape 410, the second adhesive tape 420, the third adhesive tape 430, and the fourth adhesive tape 440) are evenly distributed on the circumference of the winding core 10 to avoid the generation of large steps, so as to reduce the risk of the positive / negative electrode sheet 200 breaking and improve the overall quality and service life of the battery. Furthermore, in the first winding area, there is no edge of the active layer (including the first positive electrode active layer 120, the second positive electrode active layer 130, the first negative electrode active layer 220, and the second negative electrode active layer 230) between the positive electrode ear 610 and the negative electrode ear 620, thereby avoiding a large drop when the active layer is wound around the positive electrode ear 610 / negative electrode ear 620, further reducing the risk of the positive electrode sheet 100 / negative electrode sheet 200 breaking.

[0023] In addition, by sticking adhesive tape on the blank areas (including the first positive electrode blank area 111 and the second positive electrode blank area 112) on the positive electrode collector 110 and the blank areas (the first negative electrode blank area 211 and the second negative electrode blank area 212) on the negative electrode collector 210, the mechanical strength of the positive electrode collector 110 and the negative electrode collector 210 can be improved to avoid the risk of breaking.

[0024] In one embodiment of the present invention, the center angle of the first winding area does not exceed 180°. That is, the center angle of the second winding area is greater than 180°, so that the area where the positive electrode ear 610, the negative electrode ear 620, the end of the first positive electrode active layer 120 close to the first positive electrode blank area 111, the end of the second positive electrode active layer 130 close to the second positive electrode blank area 112, the end of the first adhesive tape 410 away from the positive electrode ear 610, the end of the second adhesive tape 420 away from the positive electrode ear 610, the end of the first negative electrode active layer 220 close to the first negative electrode blank area 211, the end of the second negative electrode active layer 230 close to the second negative electrode blank area 212, the end of the third adhesive tape 430 away from the negative electrode ear 620, and the end of the fourth adhesive tape 440 away from the negative electrode ear 620 are distributed is much greater than 180°, reducing the height difference of the formed steps.

[0025] In one embodiment of the present invention, the length of the first negative electrode active layer 220 is greater than the length of the second negative electrode active layer 230. The winding core 10 has a third reference line 530 pointing to the side of the first negative electrode active layer 220 close to the first negative electrode blank area 211 along the center of the winding core 10; the third reference line 530 is located in the second winding area. Along the winding direction of the winding core 10, the arc length between the positive electrode ear 610 and the third reference line 530 is not less than 3mm. This arrangement allows the edge of the first negative electrode active layer 220 and the positive electrode ear 610 to have a distance in the circumferential direction of the winding core 10, avoiding the two from being piled up in one place and generating a step with a large height difference, thereby further reducing the risk of the negative electrode sheet 200 breaking.

[0026] Similarly, the length of the first positive electrode active layer 120 is greater than the length of the second positive electrode active layer 130. The winding core 10 has a fourth reference line 540 pointing from the center of the winding core 10 to the side of the second adhesive tape 420 away from the positive electrode ear 610; the fourth reference line 540 is located in the second winding area. Along the winding direction of the winding core 10, the arc length between the negative electrode ear 620 and the fourth reference line 540 is not less than 3 mm. This arrangement creates a distance between the edge of the second positive electrode active layer 130 and the negative electrode ear 620 in the circumferential direction of the winding core 10, avoiding the two from being stacked together to form a step with a large height difference, thereby further reducing the risk of the negative electrode sheet 200 breaking.

[0027] In one embodiment of the present invention, the second winding region includes a first sub-region and a second sub-region; the boundary line between the first sub-region and the second sub-region extends along the radial direction of the winding core 10, and the central angle between the boundary line and the first reference line 510 is equal to the central angle between the boundary line and the second reference line 520. Parts of the first positive electrode active layer 120 close to the first positive electrode blank area 111, the second positive electrode active layer 130 close to the second positive electrode blank area 112, the first adhesive tape 410 away from the positive electrode ear 610, the second adhesive tape 420 away from the positive electrode ear 610, the first negative electrode active layer 220 close to the first negative electrode blank area 211, the second negative electrode active layer 230 close to the second negative electrode blank area 212, the third adhesive tape 430 away from the negative electrode ear 620, and the fourth adhesive tape 440 away from the negative electrode ear 620 are located in the first sub-region, and the rest are located in the second sub-region.

[0028] In this embodiment, the second winding area is evenly divided into a first sub-area and a second sub-area, and parts of the first positive electrode active layer 120 close to one end of the first positive electrode blank area 111, the second positive electrode active layer 130 close to one end of the second positive electrode blank area 112, the first adhesive tape 410 away from one end of the positive electrode ear 610, the second adhesive tape 420 away from one end of the positive electrode ear 610, the first negative electrode active layer 220 close to one end of the first negative electrode blank area 211, the second negative electrode active layer 230 close to one end of the second negative electrode blank area 212, the third adhesive tape 430 away from one end of the negative electrode ear 620, and the fourth adhesive tape 440 away from one end of the negative electrode ear 620 are located in the first sub-area, and the rest are located in the second sub-area to avoid their accumulation in a smaller range, thereby avoiding a large height difference.

[0029] Further, one end of the first negative electrode active layer 220 close to the first negative electrode blank area 211, one end of the second negative electrode active layer 230 close to the second negative electrode blank area 212, one end of the third adhesive tape 430 away from the negative electrode ear 620, and one end of the fourth adhesive tape 440 away from the negative electrode ear 620 are located in the first sub-region. One end of the first positive electrode active layer 120 close to the first positive electrode blank area 111, one end of the second positive electrode active layer 130 close to the second positive electrode blank area 112, one end of the first adhesive tape 410 away from the positive electrode ear 610, and one end of the second adhesive tape 420 away from the positive electrode ear 610 are located in the second sub-region. In this way, the first positive electrode active layer 120 is close to one end of the first positive electrode blank area 111, the second positive electrode active layer 130 is close to one end of the second positive electrode blank area 112, the first adhesive tape 410 is away from one end of the positive electrode ear 610, the second adhesive tape 420 is away from one end of the positive electrode ear 610, the first negative electrode active layer 220 is close to one end of the first negative electrode blank area 211, the second negative electrode active layer 230 is close to one end of the second negative electrode blank area 212, the third adhesive tape 430 is away from one end of the negative electrode ear 620, and the fourth adhesive tape 440 is away from one end of the negative electrode ear 620 are evenly distributed in the second winding area, so that multiple edges (edges of the wrapped active layer, adhesive tape edges, and ear edges) are not easy to overlap each other, thereby avoiding the formation of steps with large height differences.

[0030] In one embodiment of the present invention, at the end of the winding core 10, the negative electrode sheet 200 extends outside the positive electrode sheet 100 along the winding direction. Since the edges of the active layer are all located in the second winding area, the position where the negative electrode sheet 200 is wound around the positive electrode ear 610 is a blank area of ​​the negative electrode current collector. By covering the third adhesive tape 430 and the fourth adhesive tape 440 at this position, the mechanical strength of the current collector can be improved, thereby reducing the risk of breaking. Similarly, the position where the positive electrode sheet 100 is wound around the second negative electrode active layer 230 is a blank area of ​​the positive electrode current collector. By covering the first adhesive tape 410 and the second adhesive tape 420 at this position, the mechanical strength of the current collector can be improved, thereby reducing the risk of breaking.

[0031] In one embodiment of the present invention, a fifth adhesive tape 450 is pasted on the outer periphery of the core 10, which can not only reduce the risk of breaking of the negative electrode collector 210 on the outermost side of the core 10, but also prevent the winding structure of the core 10 from being loose and affecting the battery performance.

[0032] In one embodiment of the present invention, the ratio of the length of the first positive electrode blank area to the diameter of the winding core is 0-2 / 3, and the ratio of the length of the second positive electrode blank area to the diameter of the winding core is 0-1; the ratio of the length of the first negative electrode blank area to the diameter of the winding core is 0-1, and the ratio of the length of the second negative electrode blank area to the diameter of the winding core is 0-1, so that the positive electrode ear 610 and the negative electrode ear 620 fall into the first winding area. One end of the first positive electrode active layer 120 close to the first positive electrode blank area 111, one end of the second positive electrode active layer 130 close to the second positive electrode blank area 112, one end of the first adhesive tape 410 away from the positive electrode ear 610, one end of the second adhesive tape 420 away from the positive electrode ear 610, one end of the first negative electrode active layer 220 close to the first negative electrode blank area 211, one end of the second negative electrode active layer 230 close to the second negative electrode blank area 212, one end of the third adhesive tape 430 away from the negative electrode ear 620, and one end of the fourth adhesive tape 440 away from the negative electrode ear 620 fall into the second winding area.

[0033] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A winding core, characterized in that: It comprises a positive electrode sheet (100), a negative electrode sheet (200) and a separator (300), wherein the positive electrode sheet (100), the separator (300) and the negative electrode sheet (200) are wound from a head end to a tail end along a winding direction to form the winding core (10); The positive electrode sheet (100) comprises a positive electrode current collector (110) and a first positive electrode active layer (120) and a second positive electrode active layer (130) arranged on both sides of the positive electrode current collector (110); a first positive electrode blank area (111) and a second positive electrode blank area (112) are respectively arranged on both sides of the tail end of the positive electrode current collector (110); an end of the second positive electrode blank area (112) away from the second positive electrode active layer (130) is connected to a positive electrode ear (610), a first adhesive tape (410) is adhered to the first positive electrode blank area (111), and the The two ends of the first adhesive tape (410) extend to the first positive electrode active layer (120) and the positive electrode ear (610) respectively; the second adhesive tape (420) is adhered to the second positive electrode blank area (112), and the two ends of the second adhesive tape (420) extend to the second positive electrode active layer (130) and the edge of the second positive electrode blank area (112) respectively; the winding core (10) has a first reference line (510) along the center of the winding core (10) pointing to the side of the positive electrode ear (610) close to the first positive electrode active layer (120); The negative electrode sheet (200) comprises a negative electrode current collector (210) and a first negative electrode active layer (220) and a second negative electrode active layer (230) arranged on both sides of the negative electrode current collector (210); a first negative electrode blank area (211) and a second negative electrode blank area (212) are respectively arranged on both sides of the tail end of the negative electrode current collector (210); an end of the second negative electrode blank area (212) away from the second negative electrode active layer (230) is connected to a negative electrode ear (620), a third adhesive tape (430) is pasted on the first negative electrode blank area (211), and two ends of the third adhesive tape (430) extend to the first negative electrode active layer (220) and the negative electrode ear (620) respectively. ); a fourth adhesive tape (440) is pasted on the second negative electrode blank area (212), and the two ends of the fourth adhesive tape (440) extend to the second negative electrode active layer (230) and the edge of the second negative electrode blank area (212) respectively; the winding core (10) also has a second reference line (520) along the center of the winding core (10) pointing to the negative electrode ear (620) away from the first negative electrode active layer (220); the first reference line (510) and the second reference line (520) divide the winding core (10) into a first winding area and a second winding area; the positive electrode ear (610) and the negative electrode ear (620) are located in the first winding area; One end of the first positive electrode active layer (120) close to the first positive electrode blank area (111), one end of the second positive electrode active layer (130) close to the second positive electrode blank area (112), one end of the first adhesive tape (410) away from the positive electrode ear (610), one end of the second adhesive tape (420) away from the positive electrode ear (610), one end of the first negative electrode active layer (220) close to the first negative electrode blank area (211), one end of the second negative electrode active layer (230) close to the second negative electrode blank area (212), one end of the third adhesive tape (430) away from the negative electrode ear (620), and one end of the fourth adhesive tape (440) away from the negative electrode ear (620) are located in the second winding area.

2. The winding core according to claim 1, characterized in that: The central angle of the first winding area does not exceed 180°.

3. The winding core according to claim 1, characterized in that: The length of the first negative electrode active layer (220) is greater than the length of the second negative electrode active layer (230); The winding core (10) has a third reference line (530) along the center of the winding core (10) pointing to a side of the first negative electrode active layer (220) close to the first negative electrode blank area (211); the third reference line (530) is located in the second winding area; Along the winding direction of the winding core (10), the arc length between the positive electrode tab (610) and the third reference line (530) is not less than 3 mm.

4. The winding core according to claim 1, characterized in that: The length of the first positive electrode active layer (120) is greater than the length of the second positive electrode active layer (130); The winding core (10) has a fourth reference line (540) along the center of the winding core (10) pointing to the side of the second adhesive tape (420) away from the positive electrode tab (610); the fourth reference line (540) is located in the second winding area; Along the winding direction of the winding core (10), the arc length between the negative electrode ear (620) and the fourth reference line (540) is not less than 3 mm.

5. The winding core according to claim 1, characterized in that: The second winding area comprises a first sub-area and a second sub-area; a boundary line between the first sub-area and the second sub-area extends along the radial direction of the winding core (10), and a central angle between the boundary line and the first reference line (510) and a central angle between the boundary line and the second reference line (520) are equal; Parts of one end of the first positive electrode active layer (120) close to the first positive electrode blank area (111), one end of the second positive electrode active layer (130) close to the second positive electrode blank area (112), one end of the first adhesive tape (410) away from the positive electrode ear (610), one end of the second adhesive tape (420) away from the positive electrode ear (610), one end of the first negative electrode active layer (220) close to the first negative electrode blank area (211), one end of the second negative electrode active layer (230) close to the second negative electrode blank area (212), one end of the third adhesive tape (430) away from the negative electrode ear (620), and one end of the fourth adhesive tape (440) away from the negative electrode ear (620) are located in the first sub-region, and the rest are located in the second sub-region.

6. The winding core according to claim 5, characterized in that: One end of the first negative electrode active layer (220) close to the first negative electrode blank area (211), one end of the second negative electrode active layer (230) close to the second negative electrode blank area (212), one end of the third adhesive tape (430) away from the negative electrode ear (620), and one end of the fourth adhesive tape (440) away from the negative electrode ear (620) are located in the first sub-area; One end of the first positive electrode active layer (120) close to the first positive electrode blank area (111), one end of the second positive electrode active layer (130) close to the second positive electrode blank area (112), one end of the first adhesive tape (410) away from the positive electrode ear (610), and one end of the second adhesive tape (420) away from the positive electrode ear (610) are located in the second sub-area.

7. The winding core according to any one of claims 1 to 6, characterized in that: At the tail end of the winding core (10), the negative electrode sheet (200) extends outside the positive electrode sheet (100) along the winding direction.

8. The winding core according to claim 1, characterized in that: The ratio of the length of the first positive electrode blank area (111) to the diameter of the winding core (10) is 0-2 / 3, and the ratio of the length of the second positive electrode blank area (112) to the diameter of the winding core (10) is 0-2 / 3; the ratio of the length of the first negative electrode blank area (211) to the diameter of the winding core (10) is 0-1, and the ratio of the length of the second negative electrode blank area (212) to the diameter of the winding core (10) is 0-1.

9. A battery, characterized in that: It comprises a shell and a winding core (10) according to any one of claims 1 to 8, wherein the winding core (10) is arranged in the shell.

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