Secondary battery, battery pack, and electronic device
By designing the first insulating film in the secondary battery to not exceed the negative electrode active material layer area and to be wound around the outer periphery of the electrode assembly, combined with the second insulating film to isolate the current collector and the casing, the problem of poor connection caused by the insertion and connection position of the insulating film is solved, and the stability and safety of the battery are improved.
Patent Information
- Application Number
- CN202422052264.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-22
- Publication Date
- 2025-12-30
- Estimated Expiration
- 2034-08-22
AI Technical Summary
In existing secondary batteries, the first insulating film is easily inserted into the connection position between the first current collector and the side wall of the casing, leading to poor connection.
A secondary battery structure is designed in which the edge of the first insulating film facing the opening does not exceed the negative electrode active material layer film area. By winding the first insulating film around the outer periphery of the electrode assembly and setting an overlap area in the winding direction, the insulating film is prevented from being inserted into the connection position between the current collector and the side wall of the housing. At the same time, a second insulating film is used to isolate the current collector and the housing, ensuring the stability of the electrical connection.
This effectively avoids poor connection and welding, improves battery connection stability and lifespan, and enhances battery safety and energy density.
Smart Images
Figure CN223743697U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a secondary battery, a battery pack, and an electronic device. Background Technology
[0002] In the field of new energy power batteries, the application of secondary batteries is becoming increasingly widespread. For example, secondary batteries (such as lithium-ion batteries) can be used in electronic devices such as vehicles, energy storage, mobile phones, tablets, wearable devices, power banks, e-cigarettes, digital products, power tools, power units, and energy storage devices. A secondary battery consists of a casing and an electrode assembly. The electrode assembly includes a positive electrode, a first separator, a negative electrode, and a second separator, which are sequentially stacked and wound to form the electrode assembly, and then housed within the casing. However, existing secondary batteries still require further improvement in certain aspects. Utility Model Content
[0003] In view of the problems existing in the related technologies, the purpose of this utility model is to provide a secondary battery, battery pack and electronic device, so as to at least avoid the problem of poor connection caused by the first insulating film being inserted into the connection position between the first current collector and the side wall of the housing.
[0004] To achieve the above objectives, embodiments of this application provide a secondary battery, comprising: a casing having an end wall and a side wall surrounding the end wall, the side wall having an opening on the side opposite to the end wall; a positive electrode, a first separator, a negative electrode, and a second separator, sequentially stacked and wound to form an electrode assembly, the electrode assembly being housed in the casing, the negative electrode including a negative electrode tab and a negative active material layer region; a first current collector disposed on the end of the electrode assembly facing the opening, the casing being electrically connected to the negative electrode tab through the first current collector; and a first insulating film wound and attached to the outer periphery of the electrode assembly, wherein, in a first direction from the end wall to the opening, the edge of the first insulating film facing the opening does not exceed the negative active material layer region.
[0005] In the above embodiments, in the first direction from the end wall to the opening, the edge of the first insulating film facing the opening does not exceed the negative electrode active material layer film area, which can at least prevent the first insulating film from being inserted into the connection position between the first current collector and the side wall of the housing, and at least reduce the occurrence of poor connection.
[0006] In some embodiments, the positive electrode includes a positive active material layer film region and a positive electrode tab extending from the positive active material layer film region, the positive electrode tab being disposed on one side facing the end wall, wherein, in a first direction, the edge of the first insulating film extends beyond the positive active material layer film region.
[0007] In some embodiments, a first insulating film is wound and attached to the outer periphery of the electrode assembly for at least one circumference.
[0008] In some embodiments, the first insulating film overlaps in the winding direction of the electrode assembly to form a first overlapping region, the length of the first overlapping region in the winding direction being greater than 0 and less than or equal to 3 millimeters.
[0009] In some embodiments, the secondary battery further includes: a second current collector disposed between the end wall and the positive electrode tab, and a second insulating film surrounding the outer peripheral surface of the second current collector, wherein the minimum radius of the second insulating film is larger than the radius of the second current collector by R mm, and R is greater than or equal to 6.
[0010] In some embodiments, in the height direction of the secondary battery, the second insulating film overlaps with the first insulating film, and the height of the overlapping area is greater than or equal to 3 mm and less than or equal to 20 mm.
[0011] In some embodiments, the first insulating film overlaps in the winding direction of the electrode assembly to form a first overlapping region, and the second insulating film overlaps in the winding direction to form a second overlapping region, wherein the first overlapping region and the second overlapping region do not overlap in the winding direction.
[0012] In some embodiments, the first insulating film overlaps in the winding direction of the electrode assembly to form a first overlapping region, and the second insulating film overlaps in the winding direction to form a second overlapping region. The first overlapping region, the second overlapping region, the end position of the positive electrode, and the end position of the negative electrode do not overlap with each other in the winding direction. The secondary battery is a cylindrical battery, and the first current collector is welded to the sidewall.
[0013] Embodiments of this application also provide a battery pack, including any of the above-described secondary batteries.
[0014] Embodiments of this application also provide an electronic device including any of the above-described secondary batteries.
[0015] The beneficial technical effects of this utility model are as follows:
[0016] In this application, in the first direction from the end wall to the opening, the edge of the first insulating film facing the opening does not exceed the negative electrode active material layer film area, which can at least prevent the first insulating film from being inserted into the connection position between the first current collector and the side wall of the housing, and at least reduce the occurrence of poor connection. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1This is a schematic diagram of an electronic device in an embodiment of this application when it is a vehicle.
[0019] Figure 2 This is a front view of the electrode assembly of a secondary battery according to an embodiment of this application.
[0020] Figure 3 This is a partial cross-sectional schematic diagram of a secondary battery according to an embodiment of this application.
[0021] Figure 4 yes Figure 3 A magnified view of region B in the middle.
[0022] Figure 5 yes Figure 2 A schematic diagram of the negative active material layer region of the negative electrode sheet in region A, the positive active material layer region of the positive electrode sheet, and the first insulating film.
[0023] Figure 6 This is a partial schematic diagram of a secondary battery according to an embodiment of this application.
[0024] Figure 7 This is a schematic diagram of an electrode assembly according to an embodiment of this application. Detailed Implementation
[0025] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.
[0026] Embodiments of this application will be described in detail below. Throughout this specification, identical or similar components and components having identical or similar functions are indicated by similar reference numerals. The embodiments described herein with reference to the accompanying drawings are illustrative and diagrammatic in nature and are intended to provide a basic understanding of this application. The embodiments of this application should not be construed as limiting this application.
[0027] As used herein, the terms “approximately,” “generally,” “substantially,” and “about” are used to describe and indicate minor variations. When used in conjunction with an event or situation, these terms may refer to examples in which the event or situation occurred precisely or in examples in which the event or situation occurred very approximately.
[0028] In this specification, unless otherwise specified or limited, relative terms such as “central,” “longitudinal,” “lateral,” “front,” “rear,” “right,” “left,” “inner,” “outer,” “lower,” “higher,” “horizontal,” “vertical,” “above,” “below,” “above,” “below,” “top,” “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to the directions described in the discussion or depicted in the accompanying drawings. These relative terms are used for descriptive convenience only and do not require that this application be constructed or operated in a particular orientation.
[0029] For ease of description, "first," "second," "third," etc., can be used in this article to distinguish different components of a figure or a series of figures. "First," "second," "third," etc., are not intended to describe the corresponding components.
[0030] Furthermore, where there is no conflict, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.
[0031] This invention provides an electronic device 1000, which includes a battery pack 1002. The working part of the electronic device 1000 is electrically connected to the battery pack 1002 to obtain electrical power. As an example, the electronic device 1000 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 is the vehicle body, and the battery pack 1002 is located at the bottom of the vehicle body, providing electrical power for the vehicle's operation or the operation of electrical components within the vehicle. However, in other embodiments, the electronic device 1000 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 can obtain electrical power from the battery pack 1002 and perform corresponding functions, such as the fan blade rotation unit of a fan, or the vacuuming unit of a vacuum cleaner, etc. 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 1000.
[0032] For ease of explanation, the following embodiments use a vehicle as an example to illustrate the concept of electronic device 1000. See also Figure 1The vehicle has a battery pack 1002 installed inside, which can be located at the bottom, front, or rear of the vehicle body 1001. The battery pack 1002 can be used to power the vehicle; for example, it can serve as the vehicle's operating power source. The battery pack 1002 may include multiple secondary batteries (such as…) Figure 3 The secondary battery 300 in the middle and the casing that holds multiple secondary batteries.
[0033] Figure 2 This is a front view of the electrode assembly 200 of a secondary battery according to an embodiment of this application. Figure 2 As shown, the electrode assembly 200 is formed by sequentially stacking and winding a positive electrode (not shown), a separator 210, and a negative electrode 220 around a winding center line Lc. Around the periphery of the electrode assembly 200, a first insulating film 230 is wound and attached to the outer circumference of the electrode assembly 200, and the first insulating film 230 overlaps in the winding direction, meaning that the number of turns of the first insulating film 230 around the electrode assembly 200 is greater than one, resulting in a first overlapping region 233 that is thicker than other areas of the first insulating film 230. The separator 210 includes a first separator 210 and a second separator 210. Preferably, the length of the first overlap region 233 in the winding direction is greater than 0 and less than or equal to 3 mm. The first overlap region 233 ensures the safety of the electrode assembly 200. For example, a thicker first overlap region 233 can prevent foreign objects from piercing the electrode assembly 200 and can also prevent corrosive substances from entering the electrode assembly 200. To ensure the roundness of the first insulating film 230, the number of turns of the first insulating film 230 wrapped around the outer periphery of the electrode assembly 200 should not be less than one turn. If it is less than one turn, the electrode assembly will come into contact with the inner wall of the housing, leading to corrosion of the inner wall of the housing. Furthermore, configuring the first insulating film 230 to surround the electrode assembly 200 can prevent the electrode assembly 200 from contacting other components (such as...). Figure 3 The first insulating film 230 contacts the housing 320, thus providing better protection and insulation for the electrode assembly 200. The first insulating film 230 surrounds and tightens the positive and negative electrode plates, and can be used to fix the end of the electrode assembly 200 to maintain the tightness of the winding. In some embodiments, the first insulating film 230 can be synthesized from, for example, PP, PE, PET (polyethylene terephthalate), PVC (polyvinyl chloride), or other polymer materials. In some embodiments, the first insulating film 230 is generally PET tape, non-woven tape, PAA tape, etc.
[0034] The positive electrode sheet may include a positive current collector and a positive active material layer coated on both sides of the positive current collector. The portion of the positive current collector not coated with the positive active material layer constitutes the positive electrode tab. The negative electrode sheet 220 may include a negative current collector and a negative active material layer coated on both sides of the negative current collector. The portion of the negative current collector not coated with the negative active material layer constitutes the negative electrode tab. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive active material layer may include a positive active material, such as lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The material of the negative current collector can be copper, and the negative active material layer may include a negative active material, such as carbon or silicon. Figure 2 In this diagram, the separator 210 can be either a first separator or a second separator, and the negative electrode 220 shown represents the negative electrode active material layer region. In the height direction of the electrode assembly 200 surrounded by the first insulating film 230, the separator 210 is more prominent than the negative electrode active material layer region of the negative electrode 220. Furthermore, the negative electrode active material layer region of the negative electrode 220 is more prominent than the positive electrode active material layer region of the positive electrode. This is because, for example, in a lithium-ion battery, lithium ions travel from the positive electrode active material layer region of the positive electrode to the negative electrode active material layer region of the negative electrode. To ensure the negative electrode fully receives lithium ions and prevents lithium plating on the negative electrode, the negative electrode active material layer region of the negative electrode needs to be more prominent than the positive electrode active material layer region of the positive electrode. Figure 2 In the electrode assembly 200, the negative electrode tab (not shown) of the negative electrode sheet 220 is disposed at the upper end of the negative electrode assembly 200. At the upper end of the electrode assembly 200, the negative electrode active material layer film region of the negative electrode sheet 220 protrudes more than the first insulating film 230, that is, the top of the negative electrode active material layer film region of the negative electrode sheet 220 is higher than the top of the first insulating film 230.
[0035] The following reference Figure 3 , Figure 3 This is a partial cross-sectional schematic diagram of a secondary battery 300 according to an embodiment of this application. See also... Figure 3 As shown, the electrode assembly 200 is housed in the casing 320 of the secondary battery 300. The negative electrode tab 221 of the negative electrode plate 220 is electrically connected to the first current collector 310. The first current collector 310 is disposed on the end of the electrode assembly 200 facing the opening 330, with its end wall (not shown) located below the opening 330. The direction in which the end wall points towards the opening 330 is the first direction. Figure 3The direction is from bottom to top, and the first current collector 310 is electrically connected to the side wall of the housing 320. Preferably, the first current collector 310 is welded to the side wall of the housing 320. It can be understood that the negative electrode tab 221 is bent and connected to the first current collector 310, and the projection of the first current collector 310 can fall within the electrode assembly 200. At this time, the negative electrode active material layer region of the negative electrode sheet 220 is coplanar with the bottom surface of the first current collector 310. Now refer to... Figure 4 , Figure 4 It shows Figure 3 Enlarged diagram of region B in the middle. Figure 4 In the diagram, the first current collector 310 is electrically connected to the side wall of the housing 320. Preferably, the first current collector 310 and the side wall of the housing 320 are welded together by the solder mark 410 of the housing 320, or by laser penetration welding. The dashed line a shows the bottom surface of the first current collector 310, which is the coplanar area of the negative electrode active material layer film region of the aforementioned negative electrode plate 220 and the first current collector 310. It can be understood that the first insulating film 230 covers the electrode assembly 200, that is, it is closer to the side wall of the housing 320 than the negative electrode plate 220. If the first insulating film 230 protrudes more along the direction towards the opening 330 than the negative electrode active material layer film region of the negative electrode plate 220, then when the first current collector 310 is electrically connected to the side wall of the housing 320, the first insulating film 230 may be inserted into the connection position between the first current collector 310 and the side wall of the housing 320. This results in poor connection defects in the produced secondary battery 300. Furthermore, if the first current collector 310 is welded to the side wall of the housing 320, the first insulating film 230 may insert into the welding position between the first current collector 310 and the side wall of the housing 320. This leads to incomplete soldering and poor welding defects in the produced secondary battery 300. If the first insulating film 230 is limited to not exceeding the negative electrode active material layer region of the negative electrode sheet 220 along the first direction, that is, the edge of the first insulating film 230 facing the opening 330 does not exceed the top of the negative electrode active material layer region of the negative electrode sheet 220 (shown by dashed line a), then at least the occurrence of poor connection can be reduced, and further, the occurrence of incomplete soldering and poor welding can be reduced.
[0036] Now for reference Figure 5 , Figure 5 It shows Figure 2The diagram shows the negative active material layer region of the negative electrode 220, the positive active material layer region of the positive electrode, and the first insulating film 230 in region A. For ease of understanding, the separator 210 is omitted. It can be understood that the electrode assembly 200 is formed by sequentially stacking and winding the positive electrode, the first separator, the negative electrode 220, and the second separator. The first insulating film 230 surrounds the positive active material layer region of the positive electrode and the negative active material layer region of the negative electrode 220. The positive electrode has a positive electrode tab extending from the positive active material layer region, and the positive electrode tab is located at the end opposite to the negative electrode tab, i.e. Figure 2 The lower end of the middle electrode assembly 200. A cross-section is taken in region A along the axial direction of the electrode assembly 200, including the outermost layer of the positive electrode, the first diaphragm, the negative electrode 220, and the second diaphragm. Ignoring the first and second diaphragms, the negative electrode 220 is further away from the winding center Lc than the positive electrode, while the first insulating film 230 is located at the outermost edge of the electrode assembly 200, meaning the first insulating film 230 is further away from the winding center Lc than the negative electrode 220. Figure 5 In the diagram, the negative electrode active material layer region of the negative electrode 220 is schematically represented as F, the positive electrode active material layer region of the positive electrode is schematically represented as Z, and the region of the first insulating film 230 is schematically represented as J. Referring to the preceding description, it can be understood that the first insulating film 230, relative to the negative electrode active material layer region of the negative electrode 220, does not exceed a certain distance along the first direction, that is, within... Figure 5 In this case, the upper boundary of J does not exceed the upper boundary of F. Preferably, in the direction of the negative electrode tab of the negative electrode plate 220 (the first direction), that is... Figure 5In the direction from bottom to top, the upper boundary of J does not exceed the upper boundary of F and exceeds the upper boundary of Z. The first insulating film 230, relative to the negative electrode active material layer film region of the negative electrode plate 220, does not exceed the positive electrode active material layer film region of the positive electrode plate along the first direction, while exceeding it. If, in the first direction, the first insulating film 230 is close to the positive active material layer region of the positive electrode sheet, that is, the upper edge of the first insulating film 230 is close to the upper edge of the positive active material layer region of the positive electrode sheet but is coplanar or does not exceed it, it can be understood that the upper boundary of J in the first direction is close to the upper boundary of Z and is close to being coplanar or coplanar. Then, along the first direction, the overall thickness of the first insulating film 230, the positive active material layer region of the positive electrode sheet, and the negative active material layer region of the negative electrode sheet 220, defined on the plane perpendicular to the first direction, drops sharply from having a common three-layer thickness to having only a single layer of the negative active material layer region of the negative electrode sheet 220. This sharp drop in thickness can easily cause liquid accumulation in the electrode assembly 200, resulting in corrosion of the electrode assembly 200. To prevent liquid accumulation in the electrode assembly 200 and subsequent corrosion, the upper boundary of J is set to not exceed the upper boundary of F and exceed the upper boundary of Z. This means that the first insulating film 230, relative to the negative electrode active material layer region of the negative electrode sheet 220, does not exceed, while simultaneously exceeding, the positive electrode active material layer region of the positive electrode sheet along the first direction. This results in the overall thickness of the first insulating film 230, the positive electrode active material layer region of the positive electrode sheet, and the negative electrode active material layer region of the negative electrode sheet 220, defined on a plane perpendicular to the first direction. This thickness decreases from a total of three layers to a thickness consisting of two layers (the negative electrode active material layer region of the negative electrode sheet 220 and the first insulating film 230), and then further decreases to the thickness of a single layer (the negative electrode active material layer region of the negative electrode sheet 220). This gradual thickness variation at the negative end of the secondary battery 200 prevents liquid accumulation in the electrode assembly 200 and reduces corrosion.
[0037] Figure 6 This is a partial schematic diagram of a secondary battery 300 according to an embodiment of this application. (See reference) Figure 6The second current collector 610 is disposed between the end wall (not shown) and the positive electrode tab (not shown). The second insulating film 620 surrounds the outer peripheral surface of the second current collector 610. The minimum radius of the second insulating film 620 is larger than the radius of the second current collector by R mm, and R is greater than or equal to 6. Preferably, the material of the second insulating film 620 can be similar to that of the first insulating film 230. It is understood that the second current collector 610 can be electrically connected to the positive electrode tab and can have a radius smaller than that of the electrode assembly 200. The second insulating film 620 forming a film layer around the second current collector 610 can be slightly larger than the radius of the electrode assembly 200 and can have an overlapping area with the first insulating film 230 wound and attached to the outer periphery of the electrode assembly 200. Preferably, along the height direction of the secondary battery 300, the height of the overlapping area is greater than or equal to 3 mm and less than or equal to 20 mm. The height of the overlapping area within this range can provide a process window for the electrode assembly 200, preventing the electrode assembly 200 from being completely covered. It is understood that when the secondary battery 300 is in use, the electrode assembly 200 may expand. If the area of overlap between the first insulating film 230 and the second insulating film 620 in the height direction is too large, the expansion space between the electrode assembly 200 and the housing 320 of the secondary battery 300 will be compressed, reducing the safety of the secondary battery 300. The second insulating film 620 serves to isolate the second current collector 610 from the end wall and side wall of the housing 320. The second current collector 610 is positively charged while the housing 320 is negatively charged. The second insulating film 620 can prevent internal short circuits from occurring inside the secondary battery 300.
[0038] Now for reference Figure 7 , Figure 7 This is a schematic diagram of an electrode assembly 200 according to an embodiment of this application, with reference to... Figure 7As shown, the first insulating film 230 has a first overlapping region 233, and the second insulating film 620, similar to the first insulating film 230, may also have a second overlapping region 622. The first overlapping region 233 and the second overlapping region 622 do not overlap in the winding direction (JL). Due to the overlap, the first overlapping region 233 has a thickness greater than that of a single layer of the first insulating film 230, and the second overlapping region 622 also has a thickness greater than that of a single layer of the second insulating film 620. Since the first insulating film 230 and the second insulating film 620 have overlapping areas, and the first overlapping region 233 and the second overlapping region 622 do not overlap in the winding direction (JL), the diameter of the electrode assembly 200 in a local area can be reduced, that is, the maximum cylindrical diameter can be reduced, thereby ensuring the energy density of the secondary battery 300, improving the overall roundness of the electrode assembly 200, avoiding uneven diameter of the electrode assembly 200, and preventing the electrode assembly 200 from contacting the housing 320 and corroding the housing in areas with high diameter, thus improving the service life of the secondary battery 300. In some embodiments, it can be understood that the positive electrode sheet has a termination position, and the negative electrode sheet 220 also has a termination position and can be surrounded by the overlapping area of the first insulating film 230 and the second insulating film 620. Preferably, the first overlapping area 233, the second overlapping area 622, the termination position of the positive electrode sheet, and the termination position of the negative electrode sheet 220 do not overlap with each other in the winding direction (JL). This further reduces the local diameter of the electrode assembly 200, improves the overall roundness of the electrode assembly 200, avoids uneven diameter of the electrode assembly 200, and improves the service life of the secondary battery 300. In some embodiments, the secondary battery 300 is a cylindrical battery.
[0039] Embodiments of this application also provide a battery pack (such as the battery pack 1002 described above), which may include a secondary battery 300 of any of the above embodiments, and the battery pack may have the beneficial effects described above regarding the secondary battery 300.
[0040] Embodiments of this application also provide an electronic device that may include the secondary battery 300 of any of the above embodiments, and the electronic device may have the beneficial effects described above regarding the secondary battery 300.
[0041] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A secondary battery characterized by comprising: Comprising: a case having an end wall and a side wall surrounding the end wall, an opening being formed on a side of the side wall facing away from the end wall; a positive electrode tab, a first separator, a negative electrode tab, and a second separator, which are sequentially stacked and wound to form an electrode assembly, the electrode assembly being accommodated in the case, the negative electrode tab including a negative electrode tab and a negative active material layer film region; a first current collector disc provided on an end of the electrode assembly facing the opening, the case being electrically connected to the negative electrode tab through the first current collector disc, a first insulating film wound and attached to an outer periphery of the electrode assembly, wherein, in a first direction pointing from the end wall toward the opening, an edge of the first insulating film facing the opening does not exceed the negative active material layer film region.
2. The secondary battery according to claim 1, characterized in that the positive electrode tab includes a positive active material layer film region and a positive electrode tab extending from the positive active material layer film region, the positive electrode tab being provided on a side facing the end wall, wherein, in the first direction, the edge of the first insulating film exceeds the positive active material layer film region.
3. The secondary battery according to claim 1 or 2, characterized in that the first insulating film is wound and attached to the outer periphery of the electrode assembly at least one turn.
4. The secondary battery according to claim 1 or 2, characterized by the first insulating film has an overlap in a winding direction of the electrode assembly to form a first overlap region, a length of the first overlap region in the winding direction being greater than 0 and less than or equal to 3 mm.
5. The secondary battery according to claim 2, characterized by Further comprising: a second current collector disc provided between the end wall and the positive electrode tab; and a second insulating film surrounding an outer peripheral surface of the second current collector disc, wherein a minimum radius of the second insulating film is greater than a radius of the second current collector disc by Rmm, and the Rmm is greater than or equal to 6. In a height direction of the secondary battery, the second insulating film overlaps the first insulating film, a height of an area of the overlap being greater than or equal to 3 mm and less than or equal to 20 mm.
6. The secondary battery according to claim 5, characterized by the first insulating film has an overlap in a winding direction of the electrode assembly to form a first overlap region, the second insulating film having an overlap in the winding direction to form a second overlap region, 7. The secondary battery according to claim 5, characterized by wherein the first overlap region and the second overlap region do not overlap in the winding direction. the first insulating film has an overlap in a winding direction of the electrode assembly to form a first overlap region, the second insulating film having an overlap in the winding direction to form a second overlap region, 8. The secondary battery according to claim 5, characterized by wherein the first overlap region, the second overlap region, an end position of the positive electrode tab, and an end position of the negative electrode tab do not overlap with each other in the winding direction; the secondary battery is a cylindrical battery; the first current collector disc is welded to the side wall. The secondary battery according to any one of claims 1 to 8.
9. A battery pack characterized by comprising: The secondary battery according to any one of claims 1 to 8.
10. An electronic device, comprising: