Cylindrical battery, battery pack, and electronic device

Abstract

The utility model provides a kind of cylindrical battery, the cylindrical battery includes shell and electrode assembly installed in shell;Electrode assembly includes roll core, end tape and protective tape;Roll core includes outer circumferential surface and two end surfaces being oppositely arranged along axial direction;End tape is pasted on the outer circumferential surface of roll core along the winding direction of roll core, and the head end of end tape and the tail end of end tape form circumferential gap being arranged along the circumference of roll core, and axial non-coated area is formed between end tape and at least one end surface of roll core, and the part of outer circumferential surface of roll core is exposed in circumferential gap and axial non-coated area;Protective tape is pasted and at least covers the outer circumferential surface of at least one axial non-coated area along the winding direction of roll core, and the head of protective tape and the tail of protective tape at least partially overlap to form overlapping area;Circumferential gap and overlapping area are mutually spaced in the circumference of roll core, and the technical problem that stress imbalance is prone to occur under the common restraint of end tape and protective tape can be alleviated.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery technology, and in particular to a cylindrical battery, battery pack and electronic device. Background Technology

[0002] Cylindrical batteries typically have a winding core covered with sealing tape. To better balance the binding effect of the sealing tape on the core and the better wetting effect of the electrolyte on the core, an axial unsealed area is provided at the positive end of the core, which exposes part of the end on the positive electrode tab side.

[0003] To improve the insulation performance between the exposed area on the positive electrode tab side and the shell, a protective tape is designed to cover the exposed area on the positive electrode side. Under the combined restraint of the tail tape and the protective tape, the core is prone to stress imbalance, which can cause the core to deform into an ellipse, leading to interface problems and posing a safety risk. Utility Model Content

[0004] This invention provides a cylindrical battery, battery pack, and electronic device to alleviate the technical problem of stress imbalance that easily occurs in the core under the combined restraint of the finishing tape and protective tape.

[0005] This utility model provides a cylindrical battery, comprising: a housing and an electrode assembly installed within the housing; the electrode assembly includes a core, a finishing tape, and a protective tape; the core includes an outer peripheral surface and two end faces arranged opposite each other along the axial direction; the finishing tape is pasted onto the outer peripheral surface of the core along the winding direction of the core, a circumferential gap is formed between the first end and the last end of the finishing tape along the circumferential direction of the core, and an axially uncovered area is formed between the finishing tape and at least one end face of the core, the circumferential gap and the axially uncovered area exposing part of the outer peripheral surface of the core; the protective tape is pasted along the winding direction of the core and at least covers the outer peripheral surface of at least one axially uncovered area, the first end and the last end of the protective tape at least partially overlap to form an overlapping area; the circumferential gap and the overlapping area are spaced apart from each other in the circumferential direction of the core.

[0006] In one embodiment of the cylindrical battery of this utility model, on the cross section perpendicular to the central axis of the winding core, the central angle corresponding to the overlapping area is β, and the central angle corresponding to the circumferential gap is α, where β≥α.

[0007] In one embodiment of the cylindrical battery of this utility model, on the cross-section perpendicular to the central axis of the core, the central angle corresponding to the end face of the end tape between the first end of the end tape and the end face of the end of the protective tape is θ, where 0° < θ < 90°.

[0008] In one embodiment of the cylindrical battery of this utility model, θ is taken as 60°±1°.

[0009] In one embodiment of the cylindrical battery of this utility model, on the cross section perpendicular to the central axis of the winding core, the arc length of the circumferential gap is L1, and the arc length of the protective tape corresponding to θ is L3, then L3≥3×L1.

[0010] In one embodiment of the cylindrical battery of this utility model, on the cross-section perpendicular to the central axis of the winding core, the arc length of the overlapping area is L2, and the radius of the winding core is r, wherein the minimum value of L2 satisfies L1:

[0011]

[0012] In one embodiment of the cylindrical battery of this utility model, the maximum diameter of the electrode assembly is 46mm, the length of the overlapping area along the winding direction is 4mm to 7mm, and the length of the circumferential gap along the winding direction is 3mm to 7mm.

[0013] In one embodiment of the cylindrical battery of this utility model, the core includes a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive and negative electrode sheets. The positive electrode sheet, negative electrode sheet, and separator are stacked and wound to form the core. The negative electrode sheet has separators on both sides along the stacking direction, and the separators form the outer peripheral surface of the core. The positive electrode sheet includes a positive current collector and a positive active material layer coated on a portion of the positive current collector. The portion of the positive current collector without the positive active material layer forms a positive electrode tab. The negative electrode sheet includes a negative current collector and a negative active material layer coated on a portion of the negative current collector. The portion of the negative current collector without the negative active material layer forms a negative electrode tab. The positive electrode tab is located on one end face, and the negative electrode tab is located on the other end face. The finishing tape is close to the positive electrode. An axially uncovered area is formed on one side of the ear, defined as the positive end axially uncovered area. A protective tape is provided on the positive end axially uncovered area, defined as the positive end protective tape. Along the axial direction of the core, the tail tape has a first edge close to the positive electrode tab, the positive active material layer has a second edge close to the positive electrode tab, the negative active material layer has a third edge close to the positive electrode tab, the diaphragm has a fourth edge close to the positive electrode tab, and the positive end protective tape has a fifth edge away from the positive electrode tab. In the axial direction of the core, the first edge is flush with the second edge, the third edge is located between the fourth edge and the first edge, and the fifth edge is located on the side of the third edge away from the positive electrode tab. The other side of the positive end protective tape away from the fifth edge at least covers the part of the end face where the positive electrode tab is located.

[0014] In one embodiment of the cylindrical battery of this utility model, the protective tape and the finishing tape overlap in the axial direction of the core to form an axial overlap area, and the height h of the axial overlap area along the axial direction of the core is ≥2mm.

[0015] This utility model also provides a battery pack, which includes any of the cylindrical batteries described above.

[0016] This utility model also provides an electronic device, which includes the battery pack described above.

[0017] The beneficial effects of this utility model are as follows: The cylindrical battery proposed in this utility model has a circumferential gap between the first and last ends of the finishing tape, and an axially uncovered area is formed between the finishing tape and at least one end face of the core. A protective tape is wrapped around the outer circumferential surface of the axially uncovered area, and the first and last ends of the protective tape at least partially overlap to form an overlapping area. The circumferential gap and the overlapping area are spaced apart from each other in the circumferential direction of the core, which can eliminate local stress concentration points, balance the binding force at each point in the circumferential direction of the core, and improve the interface problem caused by uneven expansion of the cell due to uneven tension. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0019] In the attached diagram:

[0020] Figure 1 This is a schematic diagram of the structure of a cylindrical battery provided in one embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of an electrode assembly provided in one embodiment of the present invention;

[0022] Figure 3 In one embodiment of this utility model Figure 2 A magnified view of a section at point B in the middle;

[0023] Figure 4 This is a cross-sectional view along the axis of an electrode assembly provided in one embodiment of the present invention;

[0024] Figure 5 In one embodiment of this utility model Figure 4 A magnified view of a section at point C;

[0025] Figure 6 In one embodiment of this utility model Figure 1 AA section view in the middle;

[0026] Figure 7 In one embodiment of this utility model Figure 1 AA section view in the middle;

[0027] Figure 8 This is a schematic diagram of the battery pack provided in one embodiment of the present invention;

[0028] Figure 9 This is a schematic diagram of the structure of an electronic device provided in one embodiment of the present invention.

[0029] The attached figures are labeled as follows:

[0030] 1. Electronic device; 10. Battery pack; 11. Working part; 101. Housing; 102. Housing cover; 100. Cylindrical battery; 110. Casing; 111. End wall; 112. Side wall; 113. Opening; 120. Electrode assembly; 121. Core; 1211. Positive electrode sheet; 12111. Positive current collector; 12112. Positive active material layer; 12113. Uncoated area of ​​positive electrode; 12114. Second edge; 1212. Separator; 12121. Fourth edge; 1213. Negative electrode sheet; 12131. Negative current collector; 12132, Negative electrode active material layer; 12133, Negative electrode uncoated area; 12134, Third edge; 1214, Positive electrode tab; 1215, Negative electrode tab; 1216, Outer peripheral surface; 122, Finishing tape; 1221, Circumferential gap; 1222, Axial uncoated area; 12221, Axial uncoated area at the positive electrode; 1223, First edge; 123, Protective tape; 1231, Overlapping area; 1232, Positive electrode protective tape; 12321, Fifth edge; 124, Axial overlapping area; 130, End cap; 140, Electrode post. Detailed Implementation

[0031] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0032] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0033] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present invention.

[0034] Please see Figures 1 to 9 This utility model provides a cylindrical battery 100, a battery pack 10, and an electronic device 1. The core 121 of the cylindrical battery 100 includes a covering end tape 122 and a protective tape 123. By optimizing the covering position of the end tape 122 and the protective tape 123 on the core 121, the local stress concentration caused by tape overlap is reduced, and the elliptical deformation of the core 121 due to stress imbalance is avoided, thereby reducing the interface problems and safety risks caused by this, and improving the reliability and safety of the battery.

[0035] like Figure 1 As shown, the present invention provides a cylindrical battery 100, which includes a housing 110, an electrode assembly 120, a terminal post 140, and an end cap 130.

[0036] Please see Figure 1 The housing 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111. As long as a stable sealing and electrical connection can be formed, the connection between the end wall 111 and the side wall 112 can be achieved in various ways, such as integral stamping, integral casting, or separate welding. The circumference of the side wall 112 is not limited; it can be cylindrical or prismatic, or it can follow any other closed-loop contour that matches the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, and the side wall 112 is cylindrical, surrounding the outer edge of the end wall 111, with a circular opening 113 formed at the end of the side wall 112 facing away from the end wall 111. A receiving cavity is formed within the housing 110 formed by the end wall 111 and the side wall 112 to accommodate the electrode assembly 120, electrolyte, and other necessary battery components.

[0037] Please see Figure 1 and Figure 4The electrode assembly 120 is housed within the casing 110 and is a component in the cylindrical battery 100 where electrochemical reactions occur. The casing 110 may contain one or more electrode assemblies 120. The electrode assembly 120 includes a core 121, which includes a positive electrode 1211, a negative electrode 1213, and a separator 1212 disposed between the positive electrode 1211 and the negative electrode 1213. The positive electrode 1211, the negative electrode 1213, and the separator 1212 are stacked and wound to form the core 121. The negative electrode sheet 1213 has a diaphragm 1212 on both sides along the stacking direction. The diaphragm 1212 extends beyond the negative electrode sheet 1213 along the circumference of the core 121 and continues to be wound at least one turn for the end of the core 121. The end diaphragm 1212 forms the outer circumferential surface 1216 of the core 121, which can bind the core 121 and prevent the core 121 from unwinding.

[0038] Please see Figure 4 The positive electrode 1211 includes a positive current collector 12111 and a positive active material layer 12112 coated on a portion of the positive current collector 12111. The portion of the positive current collector 12111 without the coating of the positive active material layer 12112 is called the positive uncoated region 12113. The positive uncoated region 12113 extends from the separator 1212 along the winding axis of the core 121 and forms a positive electrode tab 1214. The negative electrode 1213 includes a negative current collector 12131 and a negative active material layer 12132 coated on a portion of the negative current collector 12131. The portion of the negative current collector 12131 without the coating of the negative active material layer 12132 is called the negative uncoated region 12133. The negative uncoated region 12133 extends from the separator 1212 along the winding axis of the core 121 and forms a negative electrode tab 1215. The core 121 includes two end faces arranged opposite each other along the axial direction, with the positive electrode tab 1214 located on one end face and the negative electrode tab 1215 located on the other end face.

[0039] Please see Figure 4 and Figure 5 A separator 1212 is disposed between the positive electrode 1211 and the negative electrode 1213 to isolate the positive active material layer 12112 and the negative active material layer 12132. Taking a lithium-ion cylindrical battery 100 as an example, the material of the positive current collector 12111 can be aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The material of the negative current collector 12131 can be copper, and the negative active material can be carbon or silicon, etc. The substrate material of the separator 1212 can be polypropylene (PP) or polyethylene (PE), etc.

[0040] Please see Figures 2 to 5The electrode assembly 120 also includes a finishing tape 122, which is adhered to the outer peripheral surface 1216 of the core 121 along the winding direction of the core 121. A circumferential gap 1221 is formed between the first and last ends of the finishing tape 122, providing a wetting channel for the electrolyte, allowing it to penetrate the core 121 more quickly and evenly. Simultaneously, the presence of the circumferential gap 1221 also partially releases the binding force of the core 121. An axially uncovered area 1222 is formed between the finishing tape 122 and at least one end face of the core 121, which further improves the wetting effect of the electrolyte on the core 121. Both the circumferential gap 1221 and the axially uncovered area 1222 expose the outer peripheral surface 1216 of the core 121.

[0041] It should be noted that the finishing tape 122 may form an axially uncovered area 1222 between only one end face of the core 121, or it may form an axially uncovered area 1222 between both end faces of the core 121. For details, please refer to [link / reference]. Figure 2 In this embodiment, an axially uncovered area 1222 is formed between the two end faces of the finishing tape 122 and the core 121.

[0042] Please see Figures 2 to 5 To prevent the positive electrode 1211 or negative electrode 1213 of the axially uncovered area 1222 from contacting the housing 110 and causing a short circuit risk, the electrode assembly 120 also includes a protective tape 123. The protective tape 123 is pasted along the winding direction of the core 121 and covers at least one axially uncovered area 1222 on the outer peripheral surface 1216 at both axial ends of the tail tape 122, thereby achieving insulation between the axially uncovered area 1222 of the core 121 and the battery housing 110. In this embodiment, the protective tape 123 covers the axially uncovered area 1222 of the core 121 near the end face where the positive electrode tab 1214 is located. The first and last ends of the protective tape 123 at least partially overlap to form an overlapping area 1231, and the overlapping area 1231 further ensures the insulation between the axially uncovered area 1222 and the battery housing 110. It should be noted that, in other embodiments, the protective tape 123 may also cover the axial uncovered area 1222 of the core 121 near the end face of the negative electrode tab 1215.

[0043] Please see Figures 2 to 3The circumferential gap 1221 and the overlapping area 1231 are spaced apart from each other in the circumferential direction of the core 121. This arrangement can avoid stress concentration caused by the circumferential gap 1221 and the overlapping area 1231, eliminate local stress concentration points, balance the binding force at various points in the circumferential direction of the core 121, and improve the interface problem caused by uneven expansion of the battery cell due to uneven tension. On the other hand, if the circumferential gap 1221 and the overlapping area 1231 overlap in the circumferential direction of the core 121 during the manufacturing process, it means that the protective tape 123 ends at the circumferential gap 1221. When the robot grips or the core 121 is picked up manually to apply the protective tape 123, the protective tape 123 needs to be cut or finished at the circumferential gap 1221, which can easily introduce foreign objects into the circumferential gap 1221. Furthermore, since the circumferential gap 1221 lacks the protection of the tape 122, its mechanical strength is lower than that of the area covered with the tape 122. Therefore, when foreign objects are introduced into the circumferential gap 1221, it is more likely to be punctured by the foreign objects, causing a short circuit within the core 121. In summary, this design improves the reliability and safety of the battery.

[0044] Please see Figure 1 Furthermore, if the positive electrode tab 1214 faces the end wall 111 or the opening 113, then the negative electrode tab 1215 faces the other end of the housing 110. In this embodiment, the positive electrode tab 1214 faces the end wall 111 and is electrically connected to the electrode post 140 so that the electrode post 140 is positively charged. The negative electrode tab 1215 faces the opening 113 and is electrically connected to the negative electrode tab 1215, thereby being negatively charged.

[0045] Please see Figure 1 The end cap 130 is sealed and installed in the opening 113; the outer edge shape of the end cap 130 corresponds to the shape of the opening 113 and is connected to the side wall 112 to seal the opening 113. The installation method of the end cap 130 includes, but is not limited to, mechanical seal or welded seal.

[0046] Please see Figure 6 and Figure 7 In one embodiment of the cylindrical battery 100 of this utility model, on a cross-section perpendicular to the central axis of the core 121, the central angle corresponding to the overlapping area 1231 is β. In the cylindrical battery 100, the included angle β can characterize the degree of overlap of the protective tape 123 along the circumferential direction of the overlapping area 1231 of the core 121. The central angle corresponding to the circumferential gap 1221 is α. In the cylindrical battery 100, the included angle α can characterize the size of the circumferential gap 1221 of the tail tape 122 along the core 121. β ≥ α is defined, that is, within the end face where the positive electrode tab 1214 is located in the electrode assembly 120, the stress concentration area of ​​the tail tape 122 is smaller than the overlapping area 1231 of the protective tape 123. It should be noted that... Figure 6 and Figure 7The two structures shown are different from the one above. Under the premise of meeting the above constraints, both can achieve the effect of better uniform stress distribution.

[0047] Please see Figure 6 and Figure 7 In one embodiment of the cylindrical battery 100 of this utility model, on a cross-section perpendicular to the central axis of the core 121, the central angle corresponding to the end face of the finishing tape 122 between the first end of the finishing tape 122 and the end face of the protective tape 123 is θ, and 0° < θ < 90°. This arrangement can limit the overlapping area 1231 and the circumferential gap 1221 to be located within a quarter circumference, thereby obtaining a higher stress neutralization effect.

[0048] Please see Figure 6 and Figure 7 In one embodiment of the cylindrical battery 100 of this utility model, the included angle θ is 60°±1°, which realizes the optimal distribution of stiffness and binding force in the circumferential direction of the core 121, thereby eliminating internal stress to the greatest extent and improving the problem of elliptical deformation.

[0049] Please see Figure 6 and Figure 7 In one embodiment of the cylindrical battery 100 of this utility model, on the cross-section perpendicular to the central axis of the core 121, the arc length of the circumferential gap 1221 is L1, and the arc length of the protective tape 123 corresponding to θ is L3, then L3≥3×L1. Under the condition of 0°<θ<90°, further limiting L3≥3×L1 can further optimize the distribution of stiffness and binding force in the circumferential direction of the core 121, thereby eliminating internal stress to a greater extent.

[0050] In one embodiment of the cylindrical battery 100 of this utility model, on a cross-section perpendicular to the central axis of the winding core 121, the arc length of the overlapping area 1231 is L2, and the radius of the winding core 121 is r, wherein the minimum value of L2 satisfies the following condition with respect to L1:

[0051]

[0052] The principle behind the above formula is explained below: Take a very small section of tape from core 121; its corresponding central angle is... The resultant force of its tension T in the radial direction is because It's very small. Based on the approximation of small angles, sin(x) ≈ x (where x is in radians), therefore... Balance the radial force projections of θ and β in the adhesive area with α in the non-adhesive area. That is, Tθ + Tβ = Tα + T 1 rad (T 1 rad is the reference). Then divide both sides by T, expressing it in angles as: θ + β = 1 rad + α; further converting to cosine form, we get: cosθ + cos(θ + β) = 1 + cosα, which is:

[0053]

[0054] The minimum value of L2 satisfies the above formula with L1, which can achieve a balance in the radial direction of the core 121 by the binding force of the finishing tape 122 and the protective tape 123 on the core 121. This ensures that the arc length L1 of the circumferential gap 1221, the arc length L2 of the overlapping area 1231, the position of the circumferential gap 1221 and the overlapping area 1231 are optimally distributed in the circumferential direction of the core 121, thereby eliminating internal stress to the greatest extent and improving the problem of elliptical deformation.

[0055] Please see Figure 2 and Figures 6 to 7 In one embodiment of the cylindrical battery 100 of this utility model, the maximum diameter of the electrode assembly 120 is 46 mm, and the length of the overlapping area 1231 along the winding direction is 4 mm to 7 mm. Figure 6 and Figure 7 As shown in L2. If L2 > 7mm, the overlapping area 1231 will have excessive local rigidity, becoming a stress concentration point. If L2 < 4mm, the adhesion may be weak, posing a risk of delamination. Therefore, 4 ≤ L2 ≤ 7mm balances adhesion reliability and stress uniformity. The circumferential gap 1221 has a length of 3mm to 5mm along the winding direction, as shown in... Figure 6 and Figure 7 As shown in L1. If L1 > 5mm, it will weaken the overall binding force of the finishing adhesive, while if L1 < 3mm, it will weaken the ability of the electrolyte to quickly and evenly penetrate into the core of the roll core 121. Therefore, 3mm ≤ L2 ≤ 5mm ensures both the wetting effect and maintains the necessary overall binding force.

[0056] Please see Figure 4 and Figure 5In one embodiment of the cylindrical battery 100 of this utility model, an axially uncovered area 1222 is formed on the side of the finishing tape 122 near the positive electrode tab 1214, defined as the positive end axially uncovered area 12221. A protective tape 123 is provided on the positive end axially uncovered area 12221, defined as the positive end protective tape 1232. Along the axial direction of the core 121, the finishing tape 122 has a first edge 1223 near the positive electrode tab 1214, the positive electrode active material layer 12112 has a second edge 12114 near the positive electrode tab 1214, and the negative electrode active material layer 12132 has a third edge 1223 near the positive electrode tab 1214. 2134, the diaphragm 1212 has a fourth edge 12121 near the positive electrode tab 1214, and the positive electrode protective tape 1232 has a fifth edge 12321 away from the positive electrode tab 1214. In the axial direction of the core 121, the first edge 1223 is flush with the second edge 12114, the third edge 12134 is located between the fourth edge 12121 and the first edge 1223, and the fifth edge 12321 is located on the side of the third edge 12134 away from the positive electrode tab 1214. The other side of the positive electrode protective tape 1232 opposite to the fifth edge 12321 at least covers the end face where the positive electrode tab 1214 is located.

[0057] The above configuration achieves the following: On the one hand, the height difference between the second edge 12114 of the positive electrode active material layer 12112, the fourth edge 12121 of the separator 1212, and the third edge 12134 of the negative electrode active material layer 12132 can form a stepped insulating barrier, blocking the burr path and preventing the burrs generated during the cutting of the positive electrode sheet 1211 from reaching the negative electrode active material layer 12132. On the other hand, along the axial direction of the core 121, the first edge 1223 of the finishing tape 122 is flush or nearly flush with the second edge 12114 of the positive electrode active material layer 12112, but does not completely cover the negative electrode active material layer 12132. This allows the negative electrode graphite exposed outside the finishing tape 122 along the axial direction of the core 121 to preferentially react with residual oxygen and moisture in the electrolyte, forming a protective effect of the sacrificial anode.

[0058] Please see Figure 2 and Figure 5The fifth edge 12321 of the protective tape 123 is located on the side opposite to the third edge 12134 of the negative electrode active material layer 12132, i.e., along the axial direction of the core 121. The protective tape 123 covers the area of ​​the negative electrode active material layer 12132 exposed outside the finishing tape 122. This arrangement ensures the isolation of the negative electrode graphite area, which preferentially reacts with residual oxygen and moisture in the electrolyte, from the metal casing 110, further improving safety performance. The other side of the positive electrode protective tape 1232 opposite to the fifth edge 12321 at least covers a portion of the end face where the positive electrode tab 1214 is located. That is, the protective tape 123 starts from an axially uncovered area 1222, extends first along the axial direction of the core 121, then extends radially along the end face of the core 121, and covers a portion of the end face of the core 121. This continuous, large-area wrapping method provides a more uniform and complete binding force locally, further improving the insulation effect between the positive electrode tab 1214 on the outer layer of the core 121 and the battery casing 110. Furthermore, it binds and shapes the positive electrode tab 1214 on the outer layer of the core 121, facilitating the insertion of the electrode assembly 120 into the casing. It should be noted that the protective tape 123 can directly cover the end face of the core 121 where the positive electrode tab 1214 is located. In some embodiments, a current collector (not shown in the figure) is welded to the end face where the positive electrode tab 1214 is located; in this case, the protective tape 123 covers the current collector.

[0059] Please see Figure 2 and Figure 3 In one embodiment of the cylindrical battery 100 of this utility model, the protective tape 123 and the finishing tape 122 overlap in the axial direction of the core 121 to form an axial overlap area 124, and the height h of the axial overlap area 124 along the axial direction is ≥2mm. This ensures that the protective tape 123 and the finishing tape 122 overlap in the axial direction of the core 121. This arrangement achieves absolutely reliable full-area insulation and completely eliminates the risk of short circuit caused by the exposure of the axially uncovered area 1222 on the side where the positive electrode tab 1214 is located.

[0060] Please see Figure 8 This utility model also provides a battery pack 10, which includes the cylindrical battery 100 described above. In one embodiment of the battery pack 10, the battery pack 10 includes a housing 101, a cover 102, and multiple cylindrical batteries 100. The multiple cylindrical batteries 100 are placed in the housing 101 and connected in series or parallel, or a combination of series and parallel connections. The cover 102 seals the housing 101 to protect the multiple cylindrical batteries 100. It should be noted that, in addition to the cylindrical battery 100 of this utility model, the battery pack 10 may also include a thermal management system, circuit board, etc. The battery pack 10 can be a battery module, a battery pack, an energy storage cabinet, etc.; these will not be described in detail here.

[0061] Please see Figure 9 This utility model also provides an electronic device 1, which includes the aforementioned battery pack 10. A working part 11 is electrically connected to the battery pack 10 to obtain electrical power. As an example, the electronic device 1 is a vehicle, which can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, but are not limited thereto. The working part 11 is the vehicle body, and the battery pack 10 is located at the bottom of the vehicle body, providing electrical power for the vehicle's operation or the operation of its internal electrical components. However, in other embodiments, the electronic device 1 can also be a mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, and power tool, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; the working part 11 can be a unit component capable of obtaining electrical power from the battery pack 10 and performing corresponding work, such as a fan blade rotation unit or a vacuum cleaner suction unit. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the aforementioned electronic device 1.

[0062] This invention discloses a cylindrical battery with a circumferential gap between the beginning and end of a sealing tape, forming an axially uncovered area between the sealing tape and at least one end face of the core. A protective tape is then wrapped around the outer circumferential surface of this axially uncovered area, with the beginning and end of the protective tape at least partially overlapping to form an overlapping area. The circumferential gap and overlapping area are staggered in the circumferential direction of the core, which eliminates local stress concentration points, balances the binding force at various points in the circumferential direction of the core, and improves the interface problems caused by uneven cell expansion due to uneven tension.

[0063] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A cylindrical battery, comprising a housing and an electrode assembly mounted within the housing, characterized in that, The electrode assembly includes: The core includes an outer peripheral surface and two end faces arranged opposite each other along the axial direction; A finishing tape is attached to the outer circumferential surface of the core along the winding direction of the core. A circumferential gap is formed between the first end and the last end of the finishing tape, and an axially uncovered area is formed between the finishing tape and at least one end face of the core. The circumferential gap and the axially uncovered area expose a portion of the outer circumferential surface of the core. A protective tape is applied along the winding direction of the core and covers at least one of the axially uncovered areas on the outer peripheral surface, wherein the beginning and end of the protective tape at least partially overlap to form an overlapping area. The circumferential gap and the overlapping area are spaced apart from each other in the circumferential direction of the core.

2. The cylindrical battery according to claim 1, characterized in that, On a cross-section perpendicular to the central axis of the core, the central angle corresponding to the overlapping area is β, the central angle corresponding to the circumferential gap is α, and β ≥ α.

3. The cylindrical battery according to claim 2, characterized in that, On a cross-section perpendicular to the central axis of the roll core, the central angle between the beginning of the finishing tape and the end face of the tail of the protective tape is θ, where 0° < θ < 90°.

4. The cylindrical battery according to claim 3, characterized in that, The value of θ is 60°±1°.

5. The cylindrical battery according to claim 3, characterized in that, On a cross-section perpendicular to the central axis of the core, the arc length of the circumferential gap is L1, and the arc length of the protective tape corresponding to θ is L3, then L3≥3×L1.

6. The cylindrical battery according to claim 5, characterized in that, On a cross-section perpendicular to the central axis of the core, the arc length of the overlapping area is L2, and the radius of the core is r, wherein the minimum value of L2 satisfies the following condition:

7. The cylindrical battery according to claim 2, characterized in that, The electrode assembly has a maximum diameter of 46 mm, the overlapping area has a length of 4 mm to 7 mm along the winding direction, and the circumferential gap has a length of 3 mm to 7 mm along the winding direction.

8. The cylindrical battery according to claim 1, characterized in that, The core includes a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive and negative electrode sheets. The positive electrode sheet, the negative electrode sheet, and the separator are stacked and wound to form the core. The negative electrode sheet has the separator on both sides along the stacking direction, and the separator forms the outer peripheral surface of the core. The positive electrode sheet includes a positive current collector and a positive active material layer coated on a portion of the positive current collector. The portion of the positive current collector not coated with the positive active material layer forms a positive electrode tab. The negative electrode sheet includes a negative current collector and a negative active material layer coated on a portion of the negative current collector. The portion of the negative current collector not coated with the negative active material layer forms a negative electrode tab. The positive electrode tab is located on one end face, and the negative electrode tab is located on the other end face. The finishing tape has the [missing information - likely a label or marking] formed on the side near the positive electrode tab. An axially uncovered area, defined as the positive end axially uncovered area, is provided with the protective tape, defined as the positive end protective tape. Along the axial direction of the core, the finishing tape has a first edge near the positive electrode tab, the positive active material layer has a second edge near the positive electrode tab, the negative active material layer has a third edge near the positive electrode tab, the diaphragm has a fourth edge near the positive electrode tab, and the positive end protective tape has a fifth edge away from the positive electrode tab. In the axial direction of the core, the first edge is flush with the second edge, the third edge is located between the fourth edge and the first edge, and the fifth edge is located on the side of the third edge away from the positive electrode tab. The other side of the positive end protective tape away from the fifth edge at least covers the portion of the end face where the positive electrode tab is located.

9. The cylindrical battery according to claim 1, characterized in that, The protective tape and the finishing tape overlap in the axial direction of the core to form an axial overlap area, and the height h of the axial overlap area along the axial direction of the core is ≥2mm.

10. A battery pack, characterized in that, The cylindrical battery includes any one of claims 1 to 9.

11. An electronic device, characterized in that, Includes the battery pack as described in claim 10.

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