Roll core, battery cell and battery

Abstract

The utility model provides a roll core, a battery cell and a battery, and relates to the technical field of batteries. The roll core comprises a roll core main body and a first tab, the roll core main body comprises a first pole piece, a diaphragm and a second pole piece and is provided with a first end part; the first tab is arranged at the first end part and is connected to the first pole piece; the second tab is connected to the second pole piece; the plurality of layers of first tabs are bent and laminated at the first end part to form a first tab region; the first end part is provided with a first tab-free area, the distances from the outer edge and the inner edge of the first tab-free area to the center of the roll core main body are G and H respectively, the outer diameter of the roll core main body is A, the diameter of a middle hole of the roll core main body is phi, and A / 4 + phi / 4 is more than H and less than G. In the application, by arranging the first tab-free area, the electrolyte can directly pass through the first tab-free area to infiltrate the pole piece at the center of the roll core thickness, so that the infiltration efficiency of the pole piece at the center of the roll core thickness can be improved. Therefore, the infiltration efficiency of the roll core can be improved.

Description

Technical Field

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

[0002] In related technologies, a battery includes a casing and a winding core disposed within the casing. The winding core includes a wound positive electrode sheet, a negative electrode sheet, and a separator. The electrode sheet includes a coated area and a hollow foil area surrounding the coated area. The coated area is used to apply the active material, while the hollow foil area serves as the tab.

[0003] In order to control the height of the tabs inside the battery cell, the tabs need to be flattened, that is, the tabs are bent toward the end face of the core so that two radially adjacent tabs are stacked along the axial direction of the core to form a tab area. However, the flattened tabs will block the end of the core. Therefore, in a full-tab battery, the electrolyte mainly flows down from the middle hole of the core to the bottom of the inner cavity of the battery cell, and then the electrolyte is adsorbed by the electrode and adsorbed to the top of the core to complete the infiltration of the core.

[0004] However, the existing core has poor wetting uniformity, which results in the core requiring a long wetting time to be fully wetted, thereby resulting in poor wetting efficiency of the core. Utility Model Content

[0005] The embodiments of the present application provide a winding core, a battery cell, and a battery, which can improve the wetting efficiency of the winding core.

[0006] In the first aspect, an embodiment of the present application provides a winding core, which includes a winding core body and a first pole piece; the winding core body includes a first pole piece, a diaphragm and a second pole piece that are wound together, the diaphragm is located between the first pole piece and the second pole piece, the polarity of the first pole piece and the second pole piece are opposite, and the winding core body has a first end along the axial direction of the winding core; the first pole piece is arranged at the first end and connected to the first pole piece; the second pole piece is connected to the second pole piece; wherein, multiple layers of first pole pieces are bent and stacked at the first end to form a first pole piece area; a first pole piece-free area is provided at the first end, and the first pole piece-free area is configured to allow electrolyte to flow into the interior of the winding core body, the distance from the outer edge of the first pole piece-free area to the center of the winding core body and the distance from the inner edge of the first pole piece-free area to the center of the winding core body are G and H respectively, and the diameter of the middle hole of the winding core body is φ, satisfying: H<A / 4+φ / 4<G.

[0007] In one embodiment, the first tab-free region extends in a ring shape along the circumference of the winding core body.

[0008] In one embodiment, there are a plurality of first tab-free regions, and the plurality of first tab-free regions are spaced apart along the circumference of the winding core body.

[0009] In one embodiment, 0.25A≤H≤0.325A.

[0010] In one embodiment, 0.3A≤G≤0.4A.

[0011] In one embodiment, along the radial direction of the winding core, the width of the first tab-free area is W1, and the unit thickness of the winding core body is d0, satisfying: 2d0≤W1≤8d0, where d0 is the sum of the thickness of a first pole piece, the thickness of a diaphragm, the thickness of a second pole piece, and the thickness of another diaphragm.

[0012] In one embodiment, with the axial direction of the winding core as the projection direction, the projected area of the first tab region is S1, and the area of the first end portion is S, satisfying: 0.5≤S1 / S<1.

[0013] In one embodiment, the first tab region extends in a ring shape along the circumference of the winding core body, and the outer diameter of the first tab region is smaller than the outer diameter of the winding core body.

[0014] In one embodiment, the outer diameter of the first tab region is B, satisfying: 0.8A≤B<A.

[0015] In one embodiment, the first tab region extends in a ring shape along the circumference of the winding core body, and the inner diameter of the first tab region is C, satisfying: 0.02A≤C≤0.25A.

[0016] In one embodiment, the winding core has a second end portion arranged opposite to the first end portion; the second pole tab is arranged at the second end portion; wherein, multiple layers of second pole tabs are bent and stacked on the second end portion to form a second pole tab area, and a second pole tab-free area is provided at the second end portion, and the second pole tab-free area is configured to allow electrolyte to flow into the interior of the winding core body.

[0017] In one embodiment, with the axial direction of the winding core as the projection direction, the projection of the first tab-free region partially overlaps with the projection of the second tab region.

[0018] In one embodiment, along the radial direction of the winding core, the width of the overlap between the projection of the first tab-free region and the projection of the second tab region is W2, and the width of the first tab-free region is W1, satisfying: 10% W1≤W2.

[0019] In one embodiment, with the axial direction of the winding core as the projection direction, the projection of the second tab-free region partially overlaps with the projection of the first tab region.

[0020] In one embodiment, along the radial direction of the winding core, the width of the overlap between the projection of the second tab-free region and the projection of the first tab region is W4, and the width of the second tab-free region is W3, satisfying: 10% W3≤W4.

[0021] In one embodiment, the second tab is disposed at the first end, multiple layers of second tabs are bent and stacked on the first end to form a second tab region, and the first tab-free region is located between the first tab region and the second tab region.

[0022] In a second aspect, an embodiment of the present application provides a battery cell, which includes a shell, a cover plate and the aforementioned winding core, wherein the cover plate and the shell are covered to define a accommodating cavity; the winding core is disposed in the accommodating cavity.

[0023] In a third aspect, an embodiment of the present application provides a battery comprising the aforementioned battery cell.

[0024] Beneficial effects of the embodiments of the present application:

[0025] In the embodiment of the present application, by providing a first tab-free region, and making the inner diameter of the first tab-free region smaller than the diameter at the center of the core thickness, and the outer diameter of the first tab-free region larger than the diameter at the center of the core thickness, the electrolyte can directly pass through the first tab-free region to infiltrate the electrode sheet at the center of the core thickness, thereby improving the infiltration efficiency of the electrode sheet at the center of the core thickness. In this way, the infiltration efficiency of the core can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 Schematic diagram of the structure of the winding core provided in an embodiment of the present application;

[0028] Figure 2 is a structural schematic diagram of the first end portion provided in an embodiment of the present application;

[0029] Figure 3 is a structural schematic diagram of another first end portion provided by an embodiment of the present application;

[0030] Figure 4 is a structural schematic diagram of the second end provided in an embodiment of the present application;

[0031] Figure 5 is a schematic diagram of a longitudinal section of a winding core provided in an embodiment of the present application;

[0032] Figure 6 is a schematic structural diagram of a battery cell provided in an embodiment of the present application;

[0033] Figure 7 It is a schematic structural diagram of a battery provided in an embodiment of the present application.

[0034] Description of reference numerals:

[0035] 001- core;

[0036] 011- core body;

[0037] 111-first end portion; 1111-first tab-free region;

[0038] 112- second end portion; 1121- second tab-free region;

[0039] 113-middle hole;

[0040] 012-first tab region; 121-first tab;

[0041] 013-second tab area; 131-second tab;

[0042] 002-battery cell; 021-housing; 022-cover;

[0043] 003-battery; 031-box. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0045] Furthermore, it should be understood that the specific embodiments described herein are intended only to illustrate and explain the present application and are not intended to limit the present application. In this application, unless otherwise indicated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the directions of the drawings in the accompanying drawings; whereas "inner" and "outer" refer to the outline of the device.

[0046] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0047] To facilitate understanding of the solution of the present application, the spline curves and arrows used in the drawings are explained here: the components indicated by the spline curves without arrows are solid components, that is, components with solid structures; the components indicated by the spline curves with arrows are virtual components, that is, components without solid structures.

[0048] Before introducing a winding core, a battery cell and a battery of the present application, some of the problems to be solved by the present application are first described in detail.

[0049] The outer diameter of the core is A, and the diameter of the center hole of the core (i.e., the inner diameter of the core) is φ. Along the radial direction of the core, the core thickness T is the difference between the outer radius A / 2 of the core and the radius φ / 2 of the center hole of the core, i.e., T = A / 2 - φ / 2. The center of the core thickness is half the thickness of the core, and its distance from the axis of the core is R. T =T / 2+φ / 2=(A / 2-φ / 2) / 2+φ / 2=A / 4+φ / 4.

[0050] Among them, after the winding of the core is completed, due to the deformation recovery force of the electrode pieces and other reasons, the center and periphery of the core will become loose, resulting in the adhesion between the electrode pieces near the center and periphery of the core being smaller than the adhesion at the center of the core thickness, which in turn causes the gap between the electrode pieces near the center and periphery to be larger than the gap between the electrode pieces at the center of the core thickness. As a result, more electrolyte can be filled between the electrode pieces near the periphery and the center of the core, so that the electrode pieces near the periphery and the center of the core are wetted first, and the electrode pieces at the center of the core thickness (that is, the distance R from the axis of the core) are wetted first. T As a result, the core is not evenly wetted, requiring a long time to wet the core, which ultimately leads to poor core wetting efficiency.

[0051] Based on this, embodiments of the present application provide a winding core, a battery cell, and a battery to solve the above-mentioned problems. This application describes the winding core, the battery cell, and the battery through the following embodiments.

[0052] See also Figure 1 , Figure 1The figure is a schematic structural diagram of a winding core 001 provided in an embodiment of the present application. The embodiment of the present application provides a winding core 001. The winding core 001 includes a winding core body 011 and a first pole piece 121. The winding core body 011 includes a first pole piece, a diaphragm, and a second pole piece that are wound together. The diaphragm is located between the first pole piece and the second pole piece. The first pole piece and the second pole piece have opposite polarities. Along the axial direction of the winding core 001, the winding core body 011 has a first end 111. A first pole piece 121 is disposed at the first end 111 and connected to the first pole piece. A second pole piece 131 is connected to the second pole piece. Multiple layers of first pole pieces 121 are stacked on the first end 111 to form a first pole piece region 012. The first pole piece region 012 extends circumferentially along the winding core body 011. A first pole piece-free region 1111 is provided at the first end 111. The first pole piece-free region 1111 is configured to allow electrolyte to flow into the interior of the winding core body 011. The distance from the outer edge of the first tab-free area 1111 to the center of the core body 011 and the distance from the inner edge of the first tab-free area 1111 to the center of the core body 011 are G and H respectively. The outer diameter of the core body 011 is A, and the diameter of the middle hole 113 of the core body 011 is φ, satisfying: H<A / 4+φ / 4<G.

[0053] Exemplarily, the first tab-free region 1111 extends in a ring shape along the circumference of the core body 011 .

[0054] It can be understood that the inner diameter and outer diameter are the diameters of the relevant parts. Before the tabs are bent, they are parallel to the axial direction of the winding core 001. After the tabs are bent, the tabs are stacked in sequence along the axial direction of the winding core 001 to form a tab area.

[0055] In addition, the first tab-free region 1111 is not provided with at least one of the bent first tab 121 , the second tab 131 , and the separator.

[0056] The first electrode sheet includes a coated area coated with an active material and an uncoated area uncoated with the active material. The first electrode tab 121 may be integrally provided as at least a portion of the uncoated area. In other embodiments, the first electrode tab 121 may be separately welded to the first electrode sheet.

[0057] In addition, the first electrode tab 121 can be a positive electrode tab or a negative electrode tab.

[0058] In this embodiment, by providing the first tab-free region 1111, and making the inner diameter of the first tab-free region 1111 smaller than the diameter at the center of the core thickness, and the outer diameter of the first tab-free region 1111 larger than the diameter at the center of the core thickness, the electrolyte can directly pass through the first tab-free region 1111 to infiltrate the electrode at the center of the core thickness, thereby improving the infiltration efficiency of the electrode at the center of the core thickness. In this way, the infiltration efficiency of the core 001 can be improved.

[0059] Furthermore, by providing a first tab-free area 1111 extending circumferentially along the winding core body 011 , expansion space can be provided for the first tab 121 that expands due to heat, thereby reducing the internal stress of the first tab 121 after thermal expansion, thereby improving the reliability of the battery.

[0060] See also Figure 2 , Figure 2 FIG. 1 is a schematic structural diagram of the first end portion 111 provided in an embodiment of the present application. In one embodiment, the first tab-free region 1111 extends in a ring shape along the circumference of the core body 011 .

[0061] In this embodiment, by extending the first tab-free area 1111 into a ring shape along the circumference of the core body 011, the electrolyte can penetrate all the pole pieces at the center of the core thickness through the first tab-free area 1111, thereby further improving the wetting efficiency of the pole pieces at the center of the core thickness.

[0062] See also Figure 3 , Figure 3 1 is a schematic diagram of another structure of the first end portion 111 provided in an embodiment of the present application. In other embodiments, there are multiple first tab-free regions 1111. The multiple first tab-free regions 1111 are spaced apart along the circumference of the core body 011.

[0063] It can be understood that the number of the first tab-free regions 1111 includes but is not limited to two, three, four, five, and six.

[0064] For example, there are five first tab-free regions 1111, and the five first tab-free regions 1111 are evenly spaced along the circumference of the winding core body 011. The central angle of the first tab-free region 1111 ranges from 45° to 68°.

[0065] In this embodiment, through the above-mentioned arrangement, on the one hand, the electrolyte can penetrate into multiple circumferential positions of the electrode sheet at the center of the core thickness through the first electrode-free area 1111, thereby improving the wetting uniformity of the electrode sheet at the center of the core thickness, and further improving the wetting efficiency of the electrode sheet at the center of the core thickness; on the other hand, the first electrode ear 121 and the current collecting disk can have a connection portion at the circumferential position of the first electrode-free area 1111, thereby improving the connection reliability between the first electrode ear 121 and the current collecting disk.

[0066] See also Figure 2 , in one embodiment, 0.225A≤H≤0.325A.

[0067] It can be understood that H includes but is not limited to: 0.225A, 0.228A, 0.23A, 0.235A, 0.24A, 0.25A, 0.26A, 0.27A, 0.28A, 0.295A, 0.3A, 0.315A, and 0.325A.

[0068] For example:

[0069] When A is 44.6mm, 10.35mm≤H≤14.495mm;

[0070] When A is 45mm, 10.125mm≤H≤14.625mm;

[0071] When A is 45.2mm, 10.17mm≤H≤14.69mm.

[0072] In this embodiment, through the above-mentioned limitation, on the one hand, it is possible to avoid the inner diameter H of the first lug-free area 1111 being too small, resulting in a smaller lug area of the first lug area 012 located on the inner diameter side of the first lug-free area 1111, thereby making the lug surface located on the inner diameter side of the first lug-free area 1111 larger, thereby improving the connection reliability between the first lug 121 located on the inner diameter side of the first lug-free area 1111 and the current collecting disk, and ensuring the current collecting area of the first lug 121, thereby controlling the internal resistance of the core 001; on the other hand, it is possible to avoid the inner diameter H of the first lug-free area 1111 being too large, resulting in poor wetting effect of the pole piece at the midpoint of the core radius, thereby enabling the first lug-free area 1111 to cover more pole pieces in the radial direction at the midpoint of the core radius, thereby improving the wetting efficiency of the pole pieces.

[0073] See also Figure 2 , in one embodiment, 0.3A≤G≤0.4A.

[0074] It can be understood that G includes but is not limited to: 0.3A, 0.31A, 0.35A, 0.33A, 0.34A, 0.346A, 0.34A, 0.35A, 0.36A, 0.37A, 0.375A, 0.38A, 0.39A, and 0.4A.

[0075] For example:

[0076] When A is 44.6mm, 13.38mm≤G≤17.84mm;

[0077] When A is 45mm, 13.5mm≤G≤18mm;

[0078] When A is 45.2mm, 13.56mm≤G≤18.08mm.

[0079] In this embodiment, through the above-mentioned limitation, on the one hand, it is possible to avoid the outer diameter G of the first lug-free area 1111 being too large, resulting in a smaller lug area of the first lug area 012 located on the outer diameter side of the first lug-free area 1111, thereby making the lug surface located on the outer diameter side of the first lug-free area 1111 larger, thereby improving the connection reliability between the first lug 121 located on the outer diameter side of the first lug-free area 1111 and the current collecting disk, and ensuring the current collecting area of the first lug 121, thereby controlling the internal resistance of the winding core 001; on the other hand, it is possible to avoid the outer diameter G of the first lug-free area 1111 being too small, resulting in poor wetting effect of the pole piece at the midpoint of the radius of the winding core, thereby enabling the first lug-free area 1111 to cover more pole pieces in the radial direction at the midpoint of the radius of the winding core, thereby improving the wetting efficiency of the pole pieces.

[0080] See also Figure 2 In one embodiment, along the radial direction of the winding core 001, the width of the first tab-free region 1111 is inch W1, and the unit thickness of the winding core body 011 is d0, satisfying: 2d0≤W1≤8d0.

[0081] The unit thickness d0 of the winding core body 011 is the sum of the thickness of a first electrode piece, the thickness of a diaphragm, the thickness of a second electrode piece, and the thickness of another diaphragm.

[0082] It can be understood that W1 includes but is not limited to: 2d0, 2.8d0, 3d0, 3.5d0, 4d0, 4.6d0, 5d0, 5.2d0, 6d0, 7.4d0, 7.6d0, 7.8d0, and 8d0.

[0083] In this embodiment, through the above-mentioned setting, on the one hand, W1 can be made to have an appropriate size to facilitate the flow of electrolyte in the first tab-free area 1111, and can cover more pole pieces in the radial direction of the core 001, so as to solve the problem of poor pole piece wetting efficiency at the midpoint of the core radius; on the other hand, it can avoid W1 being too large, resulting in a smaller area of the first tab area 012, so that the first tab 121 can meet the current collection requirements of the core 001, and the core 001 can have a suitable internal resistance.

[0084] In one embodiment, with the axial direction of the winding core 001 as the projection direction, the projected area of the first tab region 012 is S1, and the area of the first end portion 111 is S, satisfying: 0.5≤S1 / S<1.

[0085] Specifically, taking a plane perpendicular to the axial direction of the winding core as a projection plane, the area of the first tab region 012 in the projection plane is S1.

[0086] Illustratively, the ratio between the area S1 of the first tab region 012 in the projection plane and the area S of the first end portion 111 includes but is not limited to: 0.5, 0.52, 0.55, 0.58, 0.6, 0.62, 0.63, 0.64, 0.66, 0.66, 0.68, 0.7, 0.72, 0.76, 0.78, 0.8, 0.85, 0.9, and 0.95.

[0087] Further, 0.5≤S1 / S≤0.8.

[0088] In this embodiment, through the above-mentioned limitation, on the one hand, the first tab region 012 can have a sufficient area to meet the current collection requirements of the core 001; on the other hand, it can avoid the first tab region 012 being too large and causing the area of the tab-free region to be too small, thereby ensuring the wetting speed at the center of the core thickness, which is beneficial to improving the wetting efficiency of the core 001.

[0089] See also Figure 1 or Figure 2 In one embodiment, the first tab region 012 extends in a ring shape along the circumference of the core body 011 . The outer diameter of the first tab region 012 is smaller than the outer diameter of the core body 011 .

[0090] In this embodiment, by setting the outer diameter of the first pole ear area 012 to be smaller than the outer diameter of the core body 011, the first pole ear area 012 can be spaced apart from the outer periphery of the core body 011, so that after the first pole ear 121 is flattened, the first pole ear 121 can be prevented from exceeding the outer periphery of the core body 011, thereby controlling the radial size of the core 001 to facilitate the insertion of the core 001 into the shell.

[0091] See also Figure 2 In one embodiment, the outer diameter of the first tab region 012 is B, satisfying: 0.8A≤B<A.

[0092] It can be understood that B includes but is not limited to: 0.8A, 0.81A, 0.81.5A, 0.82A, 0.83A, 0.84A, 0.85A, 0.86A, 0.88A, 0.9A, 0.92A, 0.95A, and 0.99A.

[0093] For example:

[0094] When A is 44.6mm, 35.68mm≤B<44.6mm;

[0095] When A is 45mm, 36mm≤B<45mm;

[0096] When A is 45.2mm, 36.16mm≤B<45.2mm.

[0097] Furthermore, 0.8A≤B≤0.95A.

[0098] In this embodiment, through the above-mentioned limitation, on the one hand, it is possible to avoid the outer diameter of the first pole lug area 012 being too large, resulting in the spacing between it and the outer periphery of the core body 011 being too small, thereby ensuring that there is space between the outer periphery of the first pole lug area 012 and the outer periphery of the core body 011 for the first pole lug 121 to expand due to heat, thereby avoiding the first pole lug 121 to be subjected to large stress after thermal expansion; on the other hand, it is possible to avoid the outer diameter of the first pole lug area 012 being too small, resulting in a small area of the first pole lug 121, thereby ensuring the area of the first pole lug 121, so that the current collecting capacity of the first pole piece meets the requirements.

[0099] See also Figure 2 In one embodiment, the first tab region 012 extends in a ring shape along the circumference of the winding core body 011. The inner diameter of the first tab region 012 is C, which satisfies the following relationship: 0.02A≤C≤0.25A.

[0100] It can be understood that C includes but is not limited to: 0.02A, 0.06A, 0.08A, 0.1A, 0.11A, 0.12A, 0.15A, 0.18A, 0.2A, 0.4A, and 0.25A.

[0101] For example:

[0102] When A is 44.6 mm, 0.892 mm ≤ C ≤ 11.5 mm;

[0103] When A is 45mm, 0.9mm≤C≤11.25mm;

[0104] When A is 45.2mm, 0.904mm≤C≤11.3mm.

[0105] Furthermore, 0.1A≤C≤0.25A.

[0106] In this embodiment, through the above-mentioned limitation, on the one hand, it is possible to avoid the inner diameter of the first pole lug area 012 being too small, resulting in the spacing between it and the inner periphery of the core body 011 being too small, thereby ensuring that the inner periphery of the first pole lug area 012 has space for the first pole lug 121 to expand due to heat, thereby avoiding the expanded first pole lug 121 blocking the middle hole 113 of the core 001 or interfering at the center of the core 001; on the other hand, it is possible to avoid the inner diameter of the first pole lug area 012 being too large, resulting in a smaller area of the first pole lug 121, thereby ensuring the area of the first pole lug 121, so that the current collecting capacity of the first pole piece meets the requirements.

[0107] See also Figure 4 , Figure 4Schematic diagram of the structure of the second end portion 112 provided in an embodiment of the present application. In one embodiment, the winding core 001 has a second end portion 112 disposed opposite the first end portion 111. A second electrode tab 131 is disposed at the second end portion 112. Multiple layers of second electrode tabs 131 are stacked on the second end portion 112 to form a second electrode tab region 013. A second electrode tab-free region 1121 is provided at the second end portion 112. The second electrode tab-free region 1121 is configured to allow electrolyte to flow into the interior of the winding core body 011.

[0108] It can be understood that the second tab-free region 1121 is not provided with at least one of the bent first tab 121 , the second tab 131 and the separator.

[0109] Exemplarily, the second tab-free region 1121 is extended along the circumference of the core body 011 . Specifically, the second tab-free region 1121 is extended in a ring shape along the circumference of the core body 011 .

[0110] The second electrode sheet includes a coated area coated with an active material and an uncoated area uncoated with the active material. The second electrode tab 131 can be integrally provided as at least a portion of the uncoated area. In other embodiments, the second electrode tab 131 can be separately welded to the second electrode sheet.

[0111] In addition, the first electrode tab 121 may be a positive electrode tab, and the second electrode tab 131 may be a negative electrode tab.

[0112] In this embodiment, by setting the second pole ear area 013 at the second end 112, the obstruction of the second pole ear 131 to the flow of electrolyte to the electrode at the center of the core thickness can be reduced, thereby improving the efficiency of the electrolyte infiltrating the electrode at the center of the core thickness, and ultimately improving the infiltration efficiency of the core 001.

[0113] See also Figure 5 , Figure 5 Schematic diagram of the longitudinal section of the winding core 001 provided in an embodiment of the present application. In one embodiment, with the axial direction of the winding core 001 as the projection direction, the projection of the first tab-free area 1111 partially overlaps with the projection of the second tab area 013, as shown in FIG. Figure 5 Shown on the left.

[0114] Specifically, taking the plane perpendicular to the axial direction of the winding core 001 as the projection plane, the projection of the first tab-free region 1111 partially overlaps with the projection of the second tab region 013 .

[0115] The inner diameter side of the first tab-free region 1111 may overlap with the portion of the second tab-free region 013 located inside the second tab-free region 1121, or the outer diameter side of the first tab-free region 1111 may overlap with the portion of the second tab-free region 013 located outside the second tab-free region 1121. Two radially adjacent first tab-free regions 1111 may respectively overlap with the inner and outer portions of the same second tab region 013, or the second tab region 013 may overlap with at most one first tab-free region 1111.

[0116] Specifically, the projections of the plurality of first tab-free regions 1111 partially overlap with the projections of the plurality of second tab regions 013 .

[0117] In this embodiment, through the above-mentioned limitations, when the electrode liquid entering the core 001 from the first tab-free area 1111 is discharged from the second end 112, the discharge of this part of the electrolyte is slowed down due to the obstruction of the second tab area 013, so that more electrolyte can be retained in the core 001, thereby improving the electrolyte infiltration efficiency.

[0118] Specifically, along the radial direction of the winding core, the width of the overlap between the projection of the first tab-free region 1111 and the projection of the second tab region 013 is W2, and the width of the first tab-free region 1111 is W1, satisfying: 10% W1≤W2.

[0119] It can be understood that W2 includes but is not limited to 10% W1, 12% W1, 13.6% W1, 15% W1, 18% W1, 28% W1, 30% W1, 35% W1, 40% W1, 42% W1, 45% W1, and 50% W1.

[0120] Further, 10% W1≤W2≤50% W1.

[0121] In this embodiment, through the above-mentioned limitation, it is possible to avoid the overlapping area between the projection of the first tab-free area 1111 and the projection of the second tab area 013 being too small, so that the second tab area 013 can more obviously hinder the electrolyte entering from the first tab-free area 1111, thereby allowing more electrolyte to be retained in the core 001, and ultimately improving the electrolyte infiltration efficiency.

[0122] See also Figure 5 In one embodiment, with the axial direction of the winding core 001 as the projection direction, the projection of the second tab-free area 1121 partially overlaps with the projection of the first tab area 012, as shown in FIG. Figure 5 Shown on the right.

[0123] Specifically, taking the plane perpendicular to the axial direction of the winding core 001 as the projection plane, the projection of the second tab-free region 1121 partially overlaps with the projection of the first tab region 012 .

[0124] The inner diameter side of the second tab-free region 1121 may overlap with the portion of the first tab-free region 012 located inside the first tab-free region 1111, or the outer diameter side of the second tab-free region 1121 may overlap with the portion of the first tab-free region 012 located outside the first tab-free region 1111. Two radially adjacent second tab-free regions 1121 may overlap with the inner and outer portions of the same first tab region 012, respectively, or the first tab region 012 may overlap with at most one portion of the second tab-free region 1121.

[0125] Specifically, the projections of the plurality of second tab-free regions 1121 partially overlap with the projections of the plurality of first tab regions 012 .

[0126] In this embodiment, through the above-mentioned limitation, the second tab-free area 1121 and the first tab-free area 1111 can be staggered, so that the electrolyte can infiltrate more pole pieces at the center of the core thickness, thereby further improving the infiltration efficiency at the center of the core thickness.

[0127] Furthermore, the inner diameter side of the first pole lug-free region 1111 overlaps with the portion of the second pole lug region 013 located inside the second pole lug-free region 1121, and the outer diameter side of the second pole lug-free region 1121 overlaps with the portion of the first pole lug region 012 located outside the first pole lug-free region 1111, or, the outer diameter side of the first pole lug-free region 1111 overlaps with the portion of the second pole lug region 013 located outside the second pole lug-free region 1121, and the inner diameter side of the second pole lug-free region 1121 overlaps with the portion of the first pole lug region 012 located inside the first pole lug-free region 1111.

[0128] In one embodiment, along the radial direction of the winding core 001 , the width of the overlap between the projection of the second tab-free region 1121 and the projection of the first tab region 012 is W4 , and the width of the second tab-free region 1121 is W3 , satisfying: 10% W3 ≤ W4 .

[0129] It can be understood that W4 includes but is not limited to 10% W3, 12% W3, 13.6% W3, 15% W3, 18% W3, 28% W3, 30% W3, 35% W3, 40% W3, 42% W3, 45% W3, and 50% W3.

[0130] Further, 10% W3≤W4≤50% W3.

[0131] In this embodiment, through the above-mentioned limitation, it is possible to avoid the overlapping portion of the projection of the second tab-free area 1121 and the projection of the second tab-free area 013 being too small, so that the relative portion of the first tab-free area 1111 and the second tab-free area 1121 can be made smaller, so that the second tab area 013 can more obviously hinder the electrolyte from entering the first tab-free area 1111, thereby allowing more electrolyte to be retained in the core 001, and ultimately improving the electrolyte infiltration efficiency.

[0132] In one embodiment, the axial direction of the winding core 001 is the projection direction, the plane where the second end portion 112 is located is the projection plane, the area of the second tab region 013 in the projection plane is S2, the area of the second end portion 112 is S, and the following conditions are satisfied: 0.5≤S 2 / S<1. Further, 0.5≤S2 / S≤0.8.

[0133] It can be understood that the areas of both ends of the winding core 001 are equal, so the area of the second end 112 is also S.

[0134] Illustratively, the ratio between the area S2 of the second tab region 013 in the projection plane and the area S of the second end portion 112 includes but is not limited to: 0.5, 0.52, 0.55, 0.58, 0.6, 0.62, 0.63, 0.64, 0.66, 0.66, 0.68, 0.7, 0.72, 0.76, 0.78, 0.8, 0.85, 0.9, 0.95.

[0135] Further, 0.5≤S2 / S≤0.8.

[0136] In this embodiment, through the above-mentioned limitation, on the one hand, the second tab region 013 can have a sufficient area to meet the current collection requirements of the core 001; on the other hand, it can avoid the area of the second tab region 013 being too large, which would result in the area of the tab-free region being too small, thereby ensuring the wetting speed at the center of the core thickness, which is beneficial to improving the wetting efficiency of the core 001.

[0137] The outer diameter and inner diameter of the second tab-free region 1121 are I and J, respectively, and the outer diameter of the core body 011 is A, satisfying: J < A / 2 + φ / 2 < I, and J < H, I < G, or J > H, and I > G. The second tab-free region 1121 has a width W2, satisfying: 2d0 ≤ W2 ≤ 8d0.

[0138] In addition, the inner and outer diameters of the second tab region 013 are consistent with those of the first tab region 012. Specifically, the outer diameter of the second tab region 013 is D, which satisfies: 0.8A ≤ D < A, and further, 0.8A ≤ D ≤ 0.95A. The inner diameter of the second tab region 013 is F, which satisfies: 0.02A ≤ F ≤ 0.25A, and further, 0.1A ≤ F ≤ 0.25A.

[0139] In another embodiment, the second tab 131 is disposed at the first end 1111. Multiple layers of second tabs 131 are bent and stacked at the first end 1111 to form a second tab region 013. The first tab-free region 1121 is located between the first tab region 012 and the second tab region 013.

[0140] See also Figure 6 , Figure 6 Schematic diagram of the structure of a battery cell 002 provided in an embodiment of the present application. Accordingly, an embodiment of the present application provides a battery cell 002 comprising a housing 021, a cover plate 022, and the aforementioned winding core 001; the cover plate 022 and the housing 021 are combined to define a receiving cavity; the winding core 001 is disposed within the receiving cavity.

[0141] In this embodiment, by adopting the aforementioned winding core 001, the electrolyte can directly penetrate the electrode at the center of the winding core thickness through the first tab-free area 1111, thereby improving the wetting efficiency of the electrode at the center of the winding core thickness, and further improving the wetting efficiency of the battery cell 002.

[0142] See also Figure 7 , Figure 7 003 is a schematic diagram of the structure of a battery 003 provided in an embodiment of the present application. The embodiment of the present application provides a battery 003, and the battery 003 includes the aforementioned battery cell 002.

[0143] It can be understood that the battery 003 may also include a box or a base plate, and the battery cell 002 is arranged in the box, or the battery cell 002 is installed on the base plate.

[0144] In this embodiment, by using the aforementioned battery cell 002, the electrolyte can directly penetrate the electrode sheet at the center of the core thickness through the first tab-free region 1111, thereby improving the wetting efficiency of the electrode sheet at the center of the core thickness, and further improving the wetting efficiency of the battery cell 002. As a result, the wetting efficiency of the battery 003 can be improved.

[0145] The above is a detailed introduction to the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of the present application. At the same time, for those skilled in the art, based on the ideas of the present application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A winding core, characterized in that: include: A winding core body, comprising a first pole piece, a diaphragm, and a second pole piece wound together, wherein the diaphragm is located between the first pole piece and the second pole piece, the first pole piece and the second pole piece having opposite polarities, and the winding core body having a first end along the axial direction of the winding core; a first pole lug, disposed at the first end portion and connected to the first pole piece; a second pole lug connected to the second pole piece; wherein the multiple layers of the first tabs are bent and stacked at the first end portion to form a first tab region; The first end portion is provided with a first tab-free area, which is configured to allow electrolyte to flow into the interior of the core body. The distance from the outer edge of the first tab-free area to the center of the core body and the distance from the inner edge of the first tab-free area to the center of the core body are G and H respectively. The outer diameter of the core body is A, and the diameter of the middle hole of the core body is φ, satisfying: H<A / 4+φ / 4<G.

2. The winding core according to claim 1, characterized in that The first tab-free region extends in a ring shape along the circumference of the winding core body.

3. The winding core according to claim 1, characterized in that There are a plurality of first tab-free regions, and the plurality of first tab-free regions are spaced apart along the circumferential direction of the winding core body.

4. The winding core according to claim 1, wherein: 0.225A≤H≤0.325A.

5. The winding core according to claim 1, characterized in that 0.3A≤G≤0.4A.

6. The winding core according to any one of claims 1 to 5, characterized in that: Along the radial direction of the winding core, the width of the first tab-free area is W1, and the unit thickness of the winding core body is d0, satisfying: 2d0≤W1≤8d0, wherein d0 is the sum of the thickness of the first pole piece, the thickness of the diaphragm, the thickness of the second pole piece and the thickness of another diaphragm.

7. The winding core according to any one of claims 1 to 5, characterized in that: Taking the axial direction of the winding core as the projection direction, the projected area of the first tab region is S1, and the area of the first end portion is S, satisfying: 0.5≤S1 / S<1.

8. The winding core according to any one of claims 1 to 5, characterized in that: The first tab region extends in a ring shape along the circumference of the winding core body, and an outer diameter of the first tab region is smaller than an outer diameter of the winding core body.

9. The winding core according to claim 8, characterized in that The outer diameter of the first tab region is B, satisfying: 0.8A≤B<A.

10. The winding core according to any one of claims 1 to 5, characterized in that: The first tab region extends in a ring shape along the circumference of the winding core body. The inner diameter of the first tab region is C, satisfying the following: 0.02A≤C≤0.25A.

11. The winding core according to any one of claims 1 to 5, characterized in that: The winding core has a second end portion disposed opposite to the first end portion; the second tab is disposed at the second end portion; The plurality of second tabs are bent and stacked at the second end to form a second tab region. The second end is provided with a second tab-free region, which is configured to allow electrolyte to flow into the interior of the core body.

12. The winding core according to claim 11, characterized in that Taking the axial direction of the winding core as the projection direction, the projection of the first tab-free area partially overlaps with the projection of the second tab area.

13. The winding core according to claim 12, characterized in that Along the radial direction of the winding core, the width of the overlap between the projection of the first tab-free region and the projection of the second tab region is W2, and the width of the first tab-free region is W1, satisfying: 10% W1≤W2.

14. The winding core according to claim 11, characterized in that Taking the axial direction of the winding core as the projection direction, the projection of the second tab-free area partially overlaps with the projection of the first tab area.

15. The winding core according to claim 14, characterized in that Along the radial direction of the winding core, the width of the overlap between the projection of the second tab-free region and the projection of the first tab region is W4, and the width of the second tab-free region is W3, satisfying: 10% W3≤W4.

16. The winding core according to any one of claims 1 to 5, characterized in that: The second tab is disposed at the first end portion, and multiple layers of the second tab are bent and stacked on the first end portion to form a second tab region. The first tab-free region is located between the first tab region and the second tab region.

17. A battery cell, characterized in that: include: case; a cover plate, covering the shell to define a receiving cavity; And, the winding core according to any one of claims 1 to 16 is arranged in the accommodating cavity.

18. A battery, characterized in that: Comprising the battery cell as claimed in claim 17.

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