Cylindrical battery

Abstract

The utility model relates to the technical field of batteries, and provides a cylindrical battery which comprises a battery cell, an insulating film and a shell, the battery cell is positioned in the shell, the insulating film is arranged on the circumferential outer surface of the battery cell, the battery cell comprises a first pole piece, the first pole piece is provided with a first ending end along the winding direction of the battery cell, and the insulating film is provided with a starting end; the distance between the first ending end and the starting end is d, and d is more than or equal to 0 and less than or equal to 30mm, so that the distance difference between the first ending end of the first pole piece and the shell can be filled by utilizing the thickness of the insulating film, the reverse acting force of the shell on the first ending end of the first pole piece caused by subsequent battery cell expansion is reduced, and the stress on the first ending end of the first pole piece is reduced; therefore, the safe use performance of the cylindrical battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a cylindrical battery. Background Art

[0002] In the related art, the core of a cylindrical battery is a wound core formed by winding electrode sheets. After the core is wound, the wound core can be fixed at the end by using a tape to ensure the fixing ability of the core. However, due to the limitation of the tape setting method, it may affect the end of the electrode sheet. Summary of the Utility Model

[0003] The utility model provides a cylindrical battery to improve the safe use performance of the cylindrical battery.

[0004] The utility model provides a cylindrical battery, including a core, an insulating film and a housing. The core is located inside the housing, and the insulating film is arranged on the outer circumferential surface of the core. The core includes a first electrode sheet. Along the winding direction of the core, the first electrode sheet has a first end, the insulating film has a starting end, and the distance between the first end and the starting end is d, where 0 ≤ d ≤ 30 mm.

[0005] The cylindrical battery according to an embodiment of the utility model includes a core, an insulating film and a housing. The core is located inside the housing, and the insulating film is arranged on the outer circumferential surface of the core, so that the insulating film can form a fixation on the outer circumferential surface of the core and increase the fixing ability of the core. Along the winding direction of the core, the first electrode sheet of the core has a first end, the insulating film has a starting end, and the distance between the first end and the starting end is d, where 0 ≤ d ≤ 30 mm. Thus, the distance difference between the first end of the first electrode sheet and the housing can be filled by the thickness of the insulating film, reducing the reverse force of the housing on the first end of the first electrode sheet caused by the subsequent expansion of the core, reducing the stress on the first end of the first electrode sheet, and improving the safe use performance of the cylindrical battery. Brief Description of the Drawings

[0006] To better understand the present disclosure, reference may be made to the embodiments shown in the following drawings. The components in the drawings are not necessarily to scale, and related elements may be omitted to emphasize and clearly illustrate the technical features of the present disclosure. Additionally, related elements or components may have different arrangements as known in the art. Moreover, in the drawings, the same reference numerals represent the same or similar components in each drawing. Among them:

[0007] Figure 1 is a schematic structural diagram of a cylindrical battery shown according to an exemplary embodiment;

[0008] Figure 2It is a schematic diagram of the internal structure of a cylindrical battery shown according to the first exemplary embodiment;

[0009] Figure 3 It is a schematic diagram of the internal structure of a cylindrical battery shown according to the second exemplary embodiment;

[0010] Figure 4 It is a schematic diagram of the internal structure of a cylindrical battery shown according to the third exemplary embodiment;

[0011] Figure 5 It is a schematic diagram of the internal structure of a cylindrical battery shown according to the fourth exemplary embodiment.

[0012] The description of the reference numerals is as follows:

[0013] 10, battery cell; 11, first electrode tab; 111, first end; 12, second electrode tab; 121, second end; 13, separator; 131, third end; 20, insulating film; 21, starting end; 22, fourth end; 30, outer shell; 31, side wall; 32, inner cavity; 40, terminal assembly. Detailed Embodiments

[0014] Next, the technical solutions in the exemplary embodiments of the present disclosure will be clearly and completely described with reference to the accompanying drawings in the exemplary embodiments of the present disclosure. The exemplary embodiments described herein are only for illustrative purposes and are not intended to limit the protection scope of the present disclosure. Therefore, it should be understood that various modifications and changes can be made to the exemplary embodiments without departing from the protection scope of the present disclosure.

[0015] In the description of the present disclosure, unless otherwise clearly defined and limited, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; the term "plurality" means two or more; the term "and / or" includes any combination and all combinations of one or more of the related listed items. In particular, referring to "the / said" object or "one" object also means one of the possible multiple such objects.

[0016] Unless otherwise specified or described, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, an integral connection, an electrical connection, or a signal connection; "connection" can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0017] Furthermore, in the description of the present disclosure, it should be understood that the orientation terms such as "upper", "lower", "inner", and "outer" described in the exemplary embodiments of the present disclosure are described from the angles shown in the drawings and should not be construed as limitations on the exemplary embodiments of the present disclosure. It should also be understood that in the context, when an element or feature is referred to as being "on", "under", or "inside", "outside" of another element (one or more), it can not only be directly connected to the other element (one or more) "on", "under", or "inside", "outside", but also be indirectly connected to the other element (one or more) "on", "under", or "inside", "outside" through an intermediate element.

[0018] An embodiment of the present invention provides a cylindrical battery. Please refer to Figures 1 to 5 , the cylindrical battery includes a battery cell 10, an insulating film 20, and a housing 30. The battery cell 10 is located inside the housing 30. The insulating film 20 is disposed on the outer circumferential surface of the battery cell 10. The battery cell 10 includes a first electrode tab 11. Along the winding direction of the battery cell 10, the first electrode tab 11 has a first end 111. The insulating film 20 has a starting end 21, and the distance between the first end 111 and the starting end 21 is d, where 0 ≤ d ≤ 30 mm.

[0019] The cylindrical battery according to an embodiment of the present invention includes a battery cell 10, an insulating film 20, and a housing 30. The battery cell 10 is located inside the housing 30. The insulating film 20 is disposed on the outer circumferential surface of the battery cell 10, so that the insulating film 20 can fix the outer circumferential surface of the battery cell 10 and increase the fixing ability of the battery cell 10. The insulating film 20 can also provide insulating protection for the battery cell 10 and the housing 30. Along the winding direction of the battery cell 10, the first electrode tab 11 of the battery cell 10 has a first end 111, and the insulating film 20 has a starting end 21. The distance between the first end 111 and the starting end 21 is d, where 0 ≤ d ≤ 30 mm. Thus, the thickness of the insulating film 20 can be used to fill the distance difference between the first end 111 of the first electrode tab 11 and the housing 30, reducing the reverse force exerted by the housing 30 on the first end 111 of the first electrode tab 11 when the battery cell 10 expands later, and reducing the stress on the first end 111 of the first electrode tab 11, thereby improving the safe use performance of the cylindrical battery.

[0020] It should be noted that in combination with Figures 1 to 5As shown in the figure, the cylindrical battery includes a battery cell 10, an insulating film 20, and a housing 30. The insulating film 20 is disposed on the circumferential outer surface of the battery cell 10, that is, the insulating film 20 can form a coating on the circumferential outer surface of the battery cell 10, so as to fix and protect the battery cell 10. The battery cell 10 is located inside the housing 30, that is, the insulating film 20 can be located between the battery cell 10 and the housing 30. The insulating film 20 can also form an insulating protection for the battery cell 10, thereby improving the safety performance of the cylindrical battery. The circumferential outer surface of the battery cell 10 is the surface formed in the circumferential direction of the battery cell 10. This surface is cylindrical. The circumferential direction refers to the "circumferential direction", that is, the direction around the axis of the cylinder. A pole assembly 40 can be provided on the housing 30, and the battery cell 10 is electrically connected to the pole assembly 40.

[0021] Combined with Figure 3 As shown in the figure, the winding direction of the battery cell 10 can be represented as X, that is, the winding direction of the battery cell 10 is generally the spiral direction. The battery cell 10 is a wound core. The battery cell 10 includes a first pole piece 11, a second pole piece 12, and a separator 13. The separator 13 can be located between the first pole piece 11 and the second pole piece 12. After the first pole piece 11, the second pole piece 12, and the separator 13 are stacked, they can be wound on a winding core rod. For example, the winding core rod is a cylinder, and the winding direction of the battery cell 10 is the winding direction of the first pole piece 11, the second pole piece 12, and the separator 13 on the winding core rod. Both the separator 13 and the insulating film 20 can form insulation. The insulating film 20 is a structure independent of the battery cell 10, that is, the insulating film 20 and the separator 13 belong to different structures, and the insulating film 20 realizes the insulation between the battery cell 10 and the housing 30.

[0022] As Figure 3 As shown in the figure, along the winding direction X of the battery cell 10, the first pole piece 11 has a first end 111, that is, the first end 111 is the last wound end of the first pole piece 11. The insulating film 20 has a starting end 21, that is, the starting end 21 is the first end of the insulating film 20 first disposed on the battery cell 10. The distance between the first end 111 and the starting end 21 is d, 0≤d≤30mm. This can reduce the stress effect of the overlapping thickness of the insulating film 20 on the first pole piece 11 and cause indentation on the first pole piece 11. At the same time, it can also relieve the sudden change in height of the first end 111 of the first pole piece 11, thereby reducing the damage probability of the first pole piece 11. When the first pole piece 11 is a negative pole piece, it can also reduce the risk of local lithium deposition. In the related art, along the winding direction X of the battery cell 10, the distance between the end of the pole piece and the starting end of the insulating film is large. The overlapping part of the insulating film at the end will cause uneven stress on the surface of the pole piece, and there will also be a distance difference at the end of the pole piece, resulting in greater stress on the pole piece at the end. When the pole piece is a negative pole piece, it is easy to form the risk of local lithium deposition.

[0023] The distance d between the first end 111 and the starting end 21 can be measured directly along the circumferential direction of the battery cell 10. For example, it can be measured using a flexible ruler along the circumferential direction of the battery cell 10. Or, a flexible body such as a line can be used first to obtain a marking line equal in length to d, and then the length of this marking line can be measured using a measuring ruler to obtain the size of d.

[0024] The thickness of the insulating film 20 can fill the distance difference between the first end 111 of the first electrode tab 11 and the outer casing 30. The distance difference between the first end 111 and the outer casing 30 is the distance between the inner side of the first end 111 away from the outer casing 30 and the outer casing 30. The distance between the starting end 21 of the insulating film 20 and the first end 111 of the first electrode tab 11 is d. Thus, the insulating film 20 can fill this distance difference.

[0025] The distance d between the first end 111 and the starting end 21 can be 0, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm or 30 mm, etc.

[0026] It should be noted that one of the first electrode tab 11 and the second electrode tab 12 is the negative electrode tab, and the other is the positive electrode tab. The electrode tab can include a current collector and an active material layer. The current collector can be a metal foil, and the active material layer is coated on the current collector, and then a wound battery cell is formed through processes such as winding.

[0027] The current collector can be copper, aluminum or a composite material. For example, the current collector includes a polymer-based film layer and a metal layer provided on the polymer-based film layer. The metal layer can be copper or aluminum, and the polymer-based film layer can be made of polypropylene (OPP) or polyethylene terephthalate (PET). The active material layer can be a positive electrode material, such as lithium cobaltate, lithium manganate, lithium iron phosphate, lithium titanate, etc. Or, the active material layer can be a negative electrode material, such as graphite, hard carbon, soft carbon, mesocarbon microbeads, silicon-carbon and lithium titanate, etc.

[0028] The above-mentioned electrode tab can be a positive electrode tab, that is, the current collector is a positive electrode current collector and the active material layer is a positive electrode active material. The positive electrode current collector can be aluminum foil.

[0029] The above-mentioned electrode tab can be a negative electrode tab, that is, the current collector is a negative electrode current collector and the active material layer is a negative electrode active material. The negative electrode current collector can be copper foil.

[0030] In one embodiment, as Figures 3 to 5As shown, the battery cell 10 further includes a second electrode tab 12. The polarities of the first electrode tab 11 and the second electrode tab 12 are opposite. The first electrode tab 11 and the second electrode tab 12 are stacked. Along the winding direction of the battery cell 10, the second electrode tab 12 has a second end portion 121, and the first end portion 111 extends beyond the second end portion 121. Among them, the first electrode tab 11 is a negative electrode tab, and 0≤d≤25mm, so that the stress risk of the first end portion 111 of the negative electrode tab can be effectively reduced, and the risk of lithium plating on the negative electrode tab can be reduced, thereby improving the safe use performance of the cylindrical battery.

[0031] The polarities of the first electrode tab 11 and the second electrode tab 12 are opposite. The first electrode tab 11 is a negative electrode tab, and the second electrode tab 12 is a positive electrode tab. Along the winding direction of the battery cell 10, the second electrode tab 12 has a second end portion 121, and the first end portion 111 extends beyond the second end portion 121, that is, along the winding direction of the battery cell 10, the first end portion 111 is farther than the second end portion 121. After the negative electrode tab is stressed, the risk of lithium plating on it increases. Therefore, by controlling the distance d between the first end portion 111 and the starting end 21 along the winding direction of the battery cell 10, the risk of lithium plating caused by the stress on the negative electrode tab can be further controlled.

[0032] In one embodiment, the thickness of the negative electrode tab is d1, 50μm≤d1, 0≤d≤20mm. By making the negative electrode tab have a certain thickness, the energy density of the cylindrical battery can be improved, but the distance difference between the first end portion 111 and the outer shell 30 is also increased, and the possibility that the negative electrode tab is subjected to greater stress is also increasing. Therefore, by further controlling the distance d between the first end portion 111 and the starting end 21, the stress risk of the first end portion 111 of the negative electrode tab can be reduced.

[0033] The thickness of the negative electrode tab is d1. The negative electrode tab includes a negative current collector and a negative active material layer. The thickness d1 of the negative electrode tab is the total thickness of the negative active material layer. For example, if negative active material layers are provided on both opposite sides of the negative current collector, then the thickness d1 of the negative electrode tab is the total thickness of the two negative active material layers.

[0034] The thickness d1 of the negative electrode tab can be 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, 110μm or 120μm, etc., which is not limited here.

[0035] In one embodiment, as Figures 3 to 5As shown, the battery cell 10 further includes a second electrode tab 12 and a separator 13. The first electrode tab 11 and the second electrode tab 12 have opposite polarities. A part of the separator 13 is located between the first electrode tab 11 and the second electrode tab 12. The separator 13 is used to insulate between the first electrode tab 11 and the second electrode tab 12, and a part of the separator 13 is wound to form the circumferential outer surface of the battery cell 10. In the radial direction of the battery cell 10, the number of layers of the separator 13 outside the first end 111 is n, the thickness of the insulating film 20 is m, and the thickness of the separator 13 is d2, where 0.07 ≤ d2×n / m ≤ 1.44. This can not only enable the separator 13 to form an effective insulating protection for the battery cell 10, but also the insulating film 20 can further increase the insulating ability of the battery cell 10, and can avoid excessive distance difference between the first end 111 and the outer casing 30, thereby increasing the stress on the first electrode tab 11, and further reducing the risk of lithium plating in the battery cell 10.

[0036] When the thickness d2 of the separator 13 is relatively large and the number of layers is relatively large, the distance between the battery cell 10 and the outer casing 30 increases. By increasing the thickness m of the insulating film 20, the distance between the battery cell 10 and the outer casing 30 can be reduced, reducing the reverse acting force of the outer casing 30 on the electrode tab, and further reducing the risk of stress at the end of the electrode tab.

[0037] One of the first electrode tab 11 and the second electrode tab 12 is a negative electrode tab, and the other is a positive electrode tab. The separator 13 forms an insulating protection for the first electrode tab 11 and the second electrode tab 12. A part of the separator 13 is wound to form the circumferential outer surface of the battery cell 10. That is, during the winding process of the battery cell 10, the separator 13 is the last part to be wound and can be wound several more layers, thereby making the separator 13 serve as a protective layer for the battery cell 10.

[0038] Combined Figure 4 and Figure 5 As shown, the radial direction of the battery cell 10 can be represented as Y. The number of layers of the separator 13 outside the first end 111 is n, that is, the number of layers of the separator 13 that can cover the first end 111 is n. For example, taking Figure 4 and Figure 5 as an example, in the radial direction of the battery cell 10, the number of layers of the separator 13 outside the first end 111 can be 2 layers.

[0039] d2×n / m can be 0.07, 0.08, 0.09, 0.1, 0.12, 0.14, 0.15, 0.16, 0.18, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4 or 1.44, etc.

[0040] In one embodiment, as Figure 4 shown, along the winding direction of the battery cell 10, the separator 13 has a third end 131. Along the radial direction of the battery cell 10, the first end 111 and the third end 131 are on the same straight line, and 0.07 ≤ d2×n / m ≤ 0.7. On the basis of ensuring reliable insulation between the battery cell 10 and the outer shell 30, it is also possible to avoid too large a distance difference between the first end 111 and the outer shell 30, increase the stress on the first end 111, and thus effectively reduce the risk of lithium plating on the first electrode sheet 11.

[0041] Combined with Figure 4 shown, along the radial direction Y of the battery cell 10, the first end 111 and the third end 131 are on the same straight line, that is, it can be considered that the first end 111 and the third end 131 can overlap in space along the radial direction Y of the battery cell 10. When winding the battery cell 10, the separator 13 and the first electrode sheet 11 can be cut simultaneously, improving the winding efficiency. However, this also increases the distance difference between the first end 111 and the outer shell 30, the outer shell acts more strongly on the first electrode sheet 11, and the risk of damage to the first electrode sheet 11 is greater. By increasing the thickness m of the insulating film 20, the insulating film 20 can make up for the distance difference, thereby reducing the reverse force of the outer shell 30 on the first end 111 caused by the subsequent expansion of the battery cell 10 and reducing the stress on the first end 111.

[0042] Along the radial direction of the battery cell 10, the number of layers n of the separator 13 outside the first end 111 is greater than 1 and less than or equal to 4. If the number of layers n of the separator 13 outside the first end 111 is too small, the insulation performance between the first electrode sheet 11 and the outer shell 30 cannot be guaranteed; if the number of layers n of the separator 13 outside the first end 111 is too large, the distance difference between the first electrode sheet 11 and the outer shell 30 is too large, increasing the stress on the electrode sheet.

[0043] In one embodiment, as Figure 5 shown, along the winding direction of the battery cell 10, the separator 13 has a third end 131. Along the radial direction of the battery cell 10, the first end 111 and the third end 131 are not on the same straight line, and 0.1 ≤ d2×n / m ≤ 1.44. This can not only ensure the insulation ability between the battery cell 10 and the outer shell 30, but also avoid too large a force on the first end 111, and thus effectively reduce the risk of lithium plating on the first electrode sheet 11.

[0044] Combined with Figure 5As shown, along the radial direction Y of the battery cell 10, the first end 111 and the third end 131 are not on the same straight line. That is, it can be considered that the first end 111 and the third end 131 do not overlap in space along the radial direction Y of the battery cell 10. Further, it can be considered that the first end 111 and the third end 131 are in different radial directions Y of the battery cell 10, such as Figure 5 shown.

[0045] Along the radial direction Y of the battery cell 10, the first end 111 and the third end 131 are not on the same straight line. For example, taking Figure 5 as an example, along the winding direction of the battery cell 10, the third end 131 is arranged beyond the first end 111. The separator 13 forms a protection for the first electrode tab 11, reducing the overlapping risk between the first electrode tab 11 and the outer shell 30, and enabling the acting force of the outer shell 30 to act on the separator 13 preferentially. A part of the reverse acting force of the outer shell 30 on the first electrode tab 11 can be absorbed by the separator 13, and the force on the first end 111 is weakened. Thus, the thickness m of the insulating film 20 can be reduced; or, along the winding direction of the battery cell 10, the first end 111 can be arranged beyond the third end 131.

[0046] In one embodiment, the thickness of the first electrode tab 11 is d0, and the thickness of the insulating film 20 is m, where 0.4 ≤ d0 / m ≤ 4. The thicker the thickness d0 of the first electrode tab 11, the greater the distance difference between the first end 111 of the first electrode tab 11 and the outer shell 30. When the battery cell 10 expands, the stress on the first electrode tab 11 is greater, and a larger thickness m of the insulating film 20 is required. However, the thickness m of the insulating film 20 cannot be too thick either. If the thickness m of the insulating film 20 is too thick, it will affect the heat dissipation of the battery cell 10. By controlling the ratio of the thickness d0 of the first electrode tab 11 to the thickness m of the insulating film 20, the risk of lithium plating in the battery cell 10 can be effectively reduced, and it is beneficial to ensure the heat dissipation capacity of the battery cell 10.

[0047] The thickness d0 of the first electrode tab 11 is the total thickness of the active material layer. For example, if active material layers are provided on both sides of the current collector, then the thickness d0 of the first electrode tab 11 is the sum of the thicknesses of the two active material layers.

[0048] In one embodiment, the thickness of the insulating film 20 is m, and m is 50 μm - 200 μm. On the basis of ensuring that the insulating film 20 can have a reliable insulating ability, it is also possible to avoid the insulating film 20 being too thick and affecting the heat dissipation ability of the battery cell 10, thereby ensuring the safe use performance of the cylindrical battery.

[0049] If the thickness m of the insulating film 20 is too small, the insulating and protective ability of the insulating film 20 for the battery cell 10 will be relatively poor, and there may be a short-circuit risk between the electrode plate and the outer shell 30; while if the thickness m of the insulating film 20 is too large, the insulating film 20 will not only occupy a large space of the outer shell 30, which is not conducive to improving the energy density of the cylindrical battery, but also the insulating film 20 will affect the heat dissipation ability of the battery cell 10.

[0050] The thickness m of the insulating film 20 can be 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, 195μm or 200μm, etc., and there is no limitation here.

[0051] In one embodiment, the ratio of the diameter of the battery cell 10 to the diameter of the inner cavity 32 of the outer shell 30 is k, and the wall thickness of the side wall 31 of the outer shell 30 is f, k / f≥1.2 / mm, 0≤d≤25mm, which can not only ensure that the battery cell 10 has a reliable expansion space, but also reduce the stress risk of the first electrode plate 11, so as to ensure the safe use performance of the cylindrical battery.

[0052] The larger k / f is, the larger the ratio of the diameter of the battery cell 10 to the diameter of the inner cavity 32 of the outer shell 30 is, the smaller the expansion space of the battery cell 10 is, and the greater the reverse acting force of the outer shell 30 on the first electrode plate 11 is. And the smaller f is, the greater the reverse acting force of the outer shell 30 on the first electrode plate 11 is. Therefore, when k / f is larger and f is smaller, d needs to be relatively smaller, so as to form protection for the first end 111 of the first electrode plate 11.

[0053] Combined with Figure 2 As shown, the outer shell 30 has an inner cavity 32 for accommodating the battery cell 10. The inner cavity 32 is a cylindrical cavity, and the diameter of the inner cavity 32 is the diameter of the end face of the cylindrical cavity, while the diameter of the battery cell 10 is the diameter of the circumferential outer surface of the battery cell 10.

[0054] Combined with Figure 1 and Figure 2 As shown, the outer shell 30 includes a side wall 31 arranged along the circumferential direction of the battery cell 10.

[0055] k / f can be 1.2 / mm, 1.3 / mm, 1.4 / mm, 1.5 / mm or 1.6 / mm, etc.

[0056] The wall thickness f of the side wall 31 can be 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm or 0.7mm, etc.

[0057] In one embodiment, asFigure 3 As shown, along the winding direction of the battery cell 10, the insulating film 20 has a fourth end 22, and the distance between the first end 111 and the fourth end 22 is 0 - 40 mm. This can prevent the fourth end 22 of the insulating film 20 from being too far away from the first end 111 of the first electrode tab 11, resulting in the position of the fourth end 22 of the insulating film 20 being damaged due to the overlapping area and the force on the fourth end 22 of the insulating film 20.

[0058] The insulating film 20 has a fourth end 22, and the first electrode tab 11 has a first end 111. Along the winding direction of the battery cell 10, the distance between the first end 111 and the fourth end 22 can be measured as follows: It can be directly measured along the circumferential direction of the battery cell 10. For example, a flexible ruler can be used to measure the distance between the first end 111 and the fourth end 22 along the circumferential direction of the battery cell 10. Or, a flexible body such as a line can be used to obtain a marking line with the same length as the distance between the first end 111 and the fourth end 22, and then a measuring ruler can be used to measure the length of this marking line to obtain the distance between the first end 111 and the fourth end 22.

[0059] The distance between the first end 111 and the fourth end 22 can be 0, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm, 31 mm, 32 mm, 33 mm, 34 mm, 35 mm, 36 mm, 37 mm, 38 mm, 39 mm or 40 mm, etc.

[0060] In one embodiment, the insulating film 20 forms an overlapping area, and along the winding direction of the battery cell 10, the length of the overlapping area is greater than 0 and less than or equal to 10 mm. This can not only ensure the fixing ability of the insulating film 20 but also reduce the probability of the insulating film 20 being damaged by force, thereby ensuring the insulating protection ability of the insulating film 20.

[0061] The insulating film 20 forms an overlapping area. If the overlapping area is too small, the fixing ability of the insulating film 20 will be relatively poor, and there may be a risk of edge curling and even detachment from the battery cell 10. If the overlapping area is too large, it will cause the fourth end 22 of the insulating film 20 to be too far away from the first end 111 of the first electrode tab 11, and the fourth end 22 of the insulating film 20 will also have pits due to stress, thus affecting the insulating protection ability of the insulating film 20.

[0062] The overlapping area of the insulating film 20 is where a part of the insulating film 20 forms an overlay, thus forming the overlapping area. Further, it can be considered that two layers of the insulating film 20 overlap to form the overlapping area, as shown in Figure 4 and Figure 5 . The overlapping area of the insulating film 20 basically extends circumferentially. Measuring its length is relatively simple. For example, it can be measured using a tape measure.

[0063] The length of the overlapping area can be greater than 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm, etc.

[0064] In one embodiment, the insulating film 20 is bonded to the outer circumferential surface of the battery cell 10, thereby ensuring the fixing ability of the insulating film 20 and reducing the risk of the insulating film 20 detaching.

[0065] The insulating film 20 can be a tape, or the insulating film 20 can be a plastic film with an adhesive layer coated thereon, and then bonded to the outer circumferential surface of the battery cell 10.

[0066] It should be noted that the above-mentioned first end 111, second end 121, third end 131, and fourth end 22 can be respectively considered as the last wound ends of the first electrode tab 11, the second electrode tab 12, the separator 13, and the insulating film 20. Here, the specific winding process is not limited, but only described in terms of the structural form.

[0067] One embodiment of the present utility model also provides a battery pack, which includes the above-mentioned cylindrical battery.

[0068] The cylindrical battery of the battery pack according to an embodiment of the present utility model includes a battery cell 10, an insulating film 20, and a housing 30. The battery cell 10 is located inside the housing 30, and the insulating film 20 is disposed on the outer circumferential surface of the battery cell 10, thereby enabling the insulating film 20 to fix the outer circumferential surface of the battery cell 10 and increasing the fixing ability of the battery cell 10. Along the winding direction of the battery cell 10, the first electrode tab 11 of the battery cell 10 has a first end 111, the insulating film 20 has a starting end 21, and the distance between the first end 111 and the starting end 21 is d, where 0 ≤ d ≤ 30 mm. Thus, the thickness of the insulating film 20 can be used to fill the distance difference between the first end 111 of the first electrode tab 11 and the housing 30, reducing the reverse force exerted by the housing 30 on the first end 111 of the first electrode tab 11 due to the subsequent expansion of the battery cell 10, and reducing the stress on the first end 111 of the first electrode tab 11, thereby improving the safe use performance of the battery pack.

[0069] In one embodiment, the battery pack is a battery module or a battery pack. The battery pack may include a plurality of cylindrical batteries.

[0070] Those skilled in the art will readily conceive of other embodiments of the present disclosure after considering the specification and practicing the inventive concept disclosed herein. The present disclosure is intended to cover any variations, uses, or adaptations of the present invention, which follow the general principles of the present disclosure and include common general knowledge or conventional technical means in the technical field not disclosed herein. The specification and the example embodiments are only regarded as exemplary, and the true scope and spirit of the present disclosure are pointed out by the appended claims.

[0071] It should be understood that the present disclosure is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The protection scope of the present disclosure is only limited by the appended claims.

Claims

1. A cylindrical battery, characterized in that: The invention comprises a battery cell (10), an insulating film (20) and a shell (30), wherein the battery cell (10) is located in the shell (30), the insulating film (20) is arranged on the circumferential outer surface of the battery cell (10), the battery cell (10) comprises a first pole piece (11), and along the winding direction of the battery cell (10), the first pole piece (11) has a first tail end (111), the insulating film (20) has a starting end (21), and the distance between the first tail end (111) and the starting end (21) is d, 0≤d≤30mm.

2. The cylindrical battery according to claim 1, characterized in that: The battery cell (10) further comprises a second pole piece (12); the first pole piece (11) and the second pole piece (12) have opposite polarities; the first pole piece (11) and the second pole piece (12) are stacked; along the winding direction of the battery cell (10), the second pole piece (12) has a second tail end (121); and the first tail end (111) is arranged beyond the second tail end (121); Wherein, the first pole piece (11) is a negative pole piece, 0≤d≤25mm.

3. The cylindrical battery according to claim 2, characterized in that: The thickness of the negative electrode plate is d1, 50 μm≤d1, 0≤d≤20 mm.

4. The cylindrical battery according to claim 1, characterized in that: The battery cell (10) further comprises a second pole piece (12) and a diaphragm (13); the first pole piece (11) and the second pole piece (12) have opposite polarities; a portion of the diaphragm (13) is located between the first pole piece (11) and the second pole piece (12); and a portion of the diaphragm (13) is wound to form a circumferential outer surface of the battery cell (10); along the radial direction of the battery cell (10), the number of layers of the diaphragm (13) located outside the first tail end (111) is n; the thickness of the insulating film (20) is m; the thickness of the diaphragm (13) is d2, and 0.07≤d2×n / m≤1.

44.

5. The cylindrical battery according to claim 4, characterized in that: Along the winding direction of the battery core (10), the diaphragm (13) has a third tail end (131), and along the radial direction of the battery core (10), the first tail end (111) and the third tail end (131) are located on the same straight line, 0.07≤d2×n / m≤0.

7.

6. The cylindrical battery according to claim 4, characterized in that: Along the winding direction of the battery cell (10), the diaphragm (13) has a third tail end (131), and along the radial direction of the battery cell (10), the first tail end (111) and the third tail end (131) are not located on the same straight line, 0.1≤d2×n / m≤1.

44.

7. The cylindrical battery according to claim 1, characterized in that: The thickness of the first pole piece (11) is d0, the thickness of the insulating film (20) is m, and 0.4≤d0 / m≤4.

8. The cylindrical battery according to any one of claims 1 to 7, characterized in that: The thickness of the insulating film (20) is m, and m is 50 μm-200 μm.

9. The cylindrical battery according to any one of claims 1 to 7, characterized in that: The ratio of the diameter of the battery core (10) to the diameter of the inner cavity (32) of the outer shell (30) is k, the wall thickness of the side wall (31) of the outer shell (30) is f, k / f≥1.2 / mm, 0≤d≤25mm.

10. The cylindrical battery according to any one of claims 1 to 7, characterized in that: Along the winding direction of the battery core (10), the insulating film (20) has a fourth tail end (22), and the distance between the first tail end (111) and the fourth tail end (22) is 0-40 mm.

11. The cylindrical battery according to any one of claims 1 to 7, characterized in that: The insulating film (20) is formed with an overlapping area, and along the winding direction of the battery core (10), the length of the overlapping area is greater than 0 and less than or equal to 10 mm.

12. The cylindrical battery according to any one of claims 1 to 7, characterized in that: The insulating film (20) is bonded to the circumferential outer surface of the battery core (10).

Images