Secondary battery, battery pack, and electronic device

Abstract

The embodiment of the utility model provides a secondary battery, a battery pack and an electronic device, the secondary battery comprises an electrode assembly, a first pole piece of the electrode assembly comprises a first current collector and a first active material layer, an uncoated area sequentially comprises a first uncoated area, a second uncoated area and a third uncoated area along the winding direction of the first pole piece, and the first current collector and the second active material layer are arranged along the height direction; the second uncoated area comprises a first tab and a connecting area connected between the first tab and the coated area, and the first uncoated area and the third uncoated area do not comprise the first tab; and an insulating layer including a first insulating region covering the first uncoated region, a second insulating region covering the connection region, and a third insulating region covering the third uncoated region. The first width of the third insulating region in the height direction is smaller than or equal to the second width of the second insulating region. The technical scheme at least can improve the safety of the battery.

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 rechargeable batteries is becoming increasingly widespread. For example, rechargeable batteries (such as lithium-ion batteries) can be used in electronic devices such as vehicles, energy storage, mobile phones, tablets, wearable devices, power banks, digital products, power tools, power units, and energy storage devices. One type of rechargeable battery is the cylindrical battery, which includes 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 stacked sequentially and wound to form the electrode assembly, and then encapsulated in the casing. However, existing rechargeable batteries still require further improvement in some 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 improve battery safety.

[0004] According to one aspect of an embodiment of this application, a secondary battery is provided, the secondary battery including an electrode assembly, the electrode assembly including a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode, the first electrode including a first current collector and a first active material layer, the first current collector including a coated area covered by the first active material layer and an uncoated area not covered by the first active material layer along the height direction of the electrode assembly, the uncoated area sequentially including a first uncoated area, a second uncoated area, and a third uncoated area along the winding direction of the first electrode, the second uncoated area including a first tab and a connection area connecting the first tab and the coated area along the opposite direction of the height direction, neither the first uncoated area nor the third uncoated area including the first tab; and an insulating layer including a first insulating area covering the first uncoated area, a second insulating area covering the connection area, and a third insulating area covering the third uncoated area, wherein the first width of the third insulating area in the height direction is smaller than the second width of the second insulating area in the height direction.

[0005] In some embodiments, the second width ranges from 1.3mm to 2.7mm.

[0006] In some embodiments, the first insulating region has a third width in the height direction, the third width being smaller than the second width.

[0007] In some embodiments, the first width ranges from 1.3mm to 3.2mm, and the first width is consistent with the third width.

[0008] In some embodiments, the diaphragm has a first end in the height direction, the third insulating region has a first end in the height direction, and the distance by which the first end of the diaphragm extends beyond the first end of the third insulating region in the height direction ranges from 0.5 mm to 2 mm.

[0009] In some embodiments, each first electrode tab includes a first side and a second side opposite to each other in the winding direction, the first side and the second side being connected to a connection area, and the first electrode extending from the beginning of the roll to the end of the roll in the winding direction, wherein the first side and the second side are inclined toward the end of the roll.

[0010] In some embodiments, the first electrode is a positive electrode, and the secondary battery is a cylindrical battery.

[0011] In some embodiments, the secondary battery further includes: a housing for accommodating an electrode assembly, the housing including a peripheral sidewall and an end wall connected to one end of the peripheral sidewall, the other end of the peripheral sidewall having an opening, wherein a first tab faces the end wall; a terminal post passing through the end wall and electrically isolated from the end wall; and a first current collector connected between the first tab and the terminal post.

[0012] Embodiments of this application also provide a battery pack, which includes any of the above-described secondary batteries.

[0013] Embodiments of this application also provide an electronic device that includes the battery pack described above.

[0014] The beneficial technical effects of this utility model are as follows:

[0015] The above-described technical solution of this application ensures safety by providing a first uncoated area and a third uncoated area on both sides of the winding direction of the second uncoated area. Furthermore, providing an insulating layer with a large second width on the second uncoated area of ​​the electrode tab provides support for the second uncoated area of ​​the electrode tab when bending the electrode tab, preventing the risk of electrode tab insertion and ensuring no burrs at the bending corners, further improving safety. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram is shown when the electronic device according to an embodiment of this application is a vehicle.

[0018] Figure 2A perspective view of a secondary battery according to an embodiment of this application is shown.

[0019] Figure 3 A cross-sectional view of a secondary battery according to an embodiment of this application is shown.

[0020] Figure 4 A cross-sectional view of an electrode assembly according to an embodiment of this application is shown.

[0021] Figure 5 A planar schematic diagram of the positive electrode sheet in its unfolded state according to an embodiment of this application is shown.

[0022] Figure 6 This is a partial cross-sectional schematic diagram of the electrode assembly at the third insulating region of the insulating layer. Detailed Implementation

[0023] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.

[0024] 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.

[0025] As used herein, the terms “approximately,” “substantially,” “substantially,” and “about” are used to describe and indicate minor variations. When used in conjunction with an event or situation, the 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.

[0026] 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.

[0027] For ease of description, the terms "first," "second," "third," etc., are used herein to distinguish different components of a figure or a series of figures. "First," "second," "third," etc., are not intended to describe corresponding components. Furthermore, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] This application provides an electronic device 1000. For ease of explanation, the following embodiments use a vehicle as an example to illustrate the electronic device 1000. See also... Figure 1 The 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 working part of the electronic device 1000 is electrically connected to the battery pack 1002 to obtain electrical power. The vehicle 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 movement or the operation of its internal electrical components. However, in some other embodiments, the electronic device 1000 can also be a mobile phone, portable device, laptop, ship, spacecraft, electric toy, and power tool, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; the working part can obtain electrical energy from the battery pack 1002 and perform corresponding functions, such as a fan blade rotation unit or a vacuum cleaner's 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 1000.

[0029] Battery pack 1002 may include multiple secondary batteries (such as cylindrical batteries). In the following description, cylindrical batteries are used as an example of secondary batteries. Figure 2 A perspective view of a cylindrical battery 100 according to an embodiment of this application is shown. Figure 3 A cross-sectional view of a cylindrical battery 100 according to an embodiment of this application is shown.

[0030] Combination Figures 2 to 3As shown, the cylindrical battery 100 includes a housing 200, which includes a peripheral sidewall 109 and an end wall 111 connected to one end of the peripheral sidewall 109. An opening 205 is provided at the other end of the peripheral sidewall 109 opposite to the end wall 111, and a cover plate 220 covers the opening 205 of the housing 200. The cover plate 220 can be used to encapsulate the electrode assembly 120 and the electrolyte together with the housing 200. The housing 200 can be made of any of a variety of available materials, such as copper, iron, aluminum, steel, or aluminum alloy. The housing 200 can be cylindrical and define a receiving cavity in which the electrode assembly 120 is disposed. The outer diameter of the housing 200 can be determined according to the specific diameter of the electrode assembly 120; for example, the outer diameter of the housing 200 can be, for example, 18 mm, 21 mm, or 46 mm. In some embodiments, the cylindrical battery 100 may be a 4680 cylindrical battery (outer diameter 46mm, height 80mm), or a 4695 cylindrical battery (outer diameter 46mm, height 95mm), or a 46120 cylindrical battery (outer diameter 46mm, height 120mm).

[0031] Electrode assembly 120 can be mainly formed by sequentially stacking and winding a positive electrode plate, a negative electrode plate, and a separator located between the positive electrode plate and the negative electrode plate (see below). Figure 4 (Detailed Description). The wound electrode assembly 120 may have a wound center hole 120c. In some embodiments, the positive electrode may include a positive current collector and a positive active material layer, the positive active material layer being coated on a portion of the surface of the positive current collector. Uncoated areas of the positive current collector not covered by the positive coating area are used to form positive electrode tabs 125. The negative electrode may include a negative current collector and a negative active material layer, the negative active material layer being coated on a portion of the surface of the negative current collector. Uncoated areas of the negative current collector not covered by the negative coating area are used to form negative electrode tabs 124.

[0032] An inwardly protruding crimping portion 113 (also referred to as a groove) is formed on the peripheral sidewall of the housing 200 adjacent to the opening 205. An electrode assembly 120 is disposed between the end wall 111 and the crimping portion 113, and the crimping portion 113 restricts the movement of the electrode assembly 120 in the height direction Hd and the opposite direction between the end wall 111 and the crimping portion 113. The end of the peripheral sidewall 109 of the housing 200 on the opening 205 side can be configured as a rolled edge portion 32, which extends radially inward along the housing 200. The rolled edge portion 32 and the crimping portion 113 are arranged at intervals along the height direction Hd, and the crimping portion 113 and the rolled edge portion 32 can jointly clamp the cover plate 220. The cover plate 220 is electrically insulated from the housing 200.

[0033] The negative electrode tab 124 of the electrode assembly 120 faces the opening 205 and can be electrically connected to the housing 200 via a negative electrode current collector 201 located between the cover plate 220 and the electrode assembly 120, thereby making the housing 200 negatively charged. The negative electrode current collector 201 can be welded to the housing 200 by laser welding. Specifically, the welding position of the negative electrode current collector 201 to the housing 200 is located on the side of the crimp portion 113 facing the electrode assembly 120.

[0034] The cylindrical battery 100 may further include a terminal post 160 that passes through and is insulated from the end wall 111. The terminal post 160 can be electrically connected to the positive electrode tab 125 of the electrode assembly 120 via a positive current collector 202 located between the terminal post 160 and the electrode assembly 120, thereby making the terminal post 160 positively charged. In some embodiments, the terminal post 160 can be welded to the positive current collector 202 by laser penetration welding.

[0035] In one example of the cylindrical battery 100 of the present invention, the method for manufacturing the cylindrical battery 100 of the present invention includes the following steps:

[0036] Winding: A winding structure formed by stacking and winding negative electrode sheet, separator and positive electrode sheet, the uncoated part of the negative current collector of negative electrode sheet and the positive current collector of positive electrode sheet is used as positive electrode tab 125 and negative electrode tab 124, and the positive electrode tab 125 and negative electrode tab 124 are bent along the radial direction of electrode assembly 120.

[0037] Welding of current collectors to electrode assemblies: The positive current collector 202 and the negative current collector 201 are welded to the surface areas of the bent positive electrode tab 125 and the negative electrode tab 124, respectively.

[0038] Installation into the housing: The electrode assembly 120, which has been welded to the negative current collector 201 and the positive current collector 202, is installed into the housing 200 through the opening 205. The method of installing the electrode assembly 120 in this step is not limited. For example, it can be installed manually or by a robot.

[0039] Install pole 160.

[0040] Electrolyte injection: The method of electrolyte injection is not limited, and injection can be carried out through opening 205. In this embodiment, electrolyte is injected through opening 205, which reduces the step of opening an injection hole in the end wall 111. The existing opening 205 can be used directly for injection, simplifying the process and reducing costs.

[0041] Sealing: The cover plate 220 is sealed and installed on the opening 205. There are various sealing methods, and this is not limited to one. In some embodiments, a pressing portion 113 recessed towards the center of the housing 200 is first formed by rolling the outer periphery of the housing 200 to restrict the movement of the electrode assembly 120 in the height direction Hd. Then, a mechanical sealing process is used to press and seal the cover plate 220 to form a rolled edge portion 32, thereby sealing and installing the cover plate 220 on the opening 205 of the housing 200. This step is a mature process, low in cost, and highly efficient.

[0042] Figure 4 A cross-sectional view of an electrode assembly 120 according to some embodiments is shown. See also Figure 4 As shown, the electrode assembly 120 is mainly formed by winding a negative electrode 10 and a positive electrode 20, and a separator 122 is provided between the negative electrode 10 and the positive electrode 20. Electrolyte can be filled between the negative electrode 10, the positive electrode 20 and the separator 122.

[0043] The negative electrode 10 may include a negative electrode current collector 18 and a negative electrode active material layer 16, wherein a portion of the opposing surfaces of the negative electrode current collector 18 along its thickness direction is covered by the negative electrode active material layer 16. The negative electrode current collector 18 includes a coated area 18a not covered by the negative electrode active material layer 16 and an uncoated area 18b not covered by the negative electrode active material layer 16. The positive electrode 20 includes a positive electrode current collector 28 and a positive electrode active material layer 26, wherein at least a portion of the opposing surfaces of the positive electrode current collector 28 along its thickness direction is covered by the positive electrode active material layer 26. The positive electrode current collector 28 includes a positive electrode coated area 28a covered by the positive electrode active material layer 26 and a positive electrode uncoated area 28b not covered by the positive electrode active material layer 26.

[0044] The uncoated area 18a of the negative current collector 18 and the uncoated positive area 28b of the positive current collector 28 are located at opposite ends in the height direction Hd of the electrode assembly 120. The uncoated area 18a of the negative current collector 18 can be used to form the negative electrode tab 124. The uncoated positive area 28b of the positive current collector 28 can be used to form the positive electrode tab 125. The uncoated negative area 18b of the negative current collector 18 can be bent toward the winding center hole 120c of the electrode assembly 120. The bent uncoated negative areas 18b can be stacked on top of each other. The stacked uncoated negative areas 18b can be welded to the negative current collector 201 and further electrically connected to the housing 200 (see...). Figure 3 ).

[0045] Taking a lithium-ion battery as an example, the material of the negative electrode current collector 18 can be, for example, copper, and the negative electrode current collector 18 can be copper foil. The negative electrode active material of the negative electrode active material layer 16 can be carbon or silicon, etc. The material of the positive electrode current collector 28 can be, for example, aluminum, and the positive electrode active material of the positive electrode active material layer 26 can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The material of the separator 122 can be PP (polypropylene) or PE (polyethylene), etc.

[0046] Figure 5 A planar schematic diagram of the positive electrode sheet in its unfolded state according to an embodiment of this application is shown. (In conjunction with...) Figure 4 and Figure 5 As shown, the positive electrode sheet 20 is wound from the beginning of the roll 20b to the end of the roll 20e along the winding direction Dj. Along the winding direction Dj, the uncoated positive electrode region 28b sequentially includes a first uncoated positive electrode region 28b1, a second uncoated positive electrode region 28b2, and a third uncoated positive electrode region 28b3. In the opposite direction of the height direction Hd, the second uncoated positive electrode region 28b2 includes a positive electrode tab 28b21 and a positive electrode connection region 28b22 connecting the positive electrode tab 28b2 and the coated positive electrode region 28a. Neither the first uncoated positive electrode region 28b1 nor the third uncoated positive electrode region 28b3 includes a positive electrode tab 28b21.

[0047] In some embodiments, the positive electrode tab 28b21 is formed by cutting a corresponding portion of the uncoated positive electrode area 28b. The positive electrode tab 28b21 can be bent toward the winding center hole 120c, and the bent positive electrode tabs 28b21 are stacked on top of each other. The stacked positive electrode tabs 28b21 can be further electrically connected to the terminal post 160 (see positive electrode current collector 202) through the positive electrode current collector 202. Figure 3 ).

[0048] To minimize the possibility of contact between the negative electrode 10 and the positive electrode 20, the electrode assembly 120 may further include an insulating layer 40. The insulating layer 40 may be provided on both sides of the uncoated positive electrode region 28b of the positive current collector 28. The insulating layer 40 effectively prevents electrical contact between the negative electrode 10 and the positive electrode 20.

[0049] In some embodiments, the insulating layer 40 is mainly composed of boehmite and PVDF (polyvinylidene fluoride). Boehmite accounts for 80% of the composition, and PVDF accounts for 20%. In some embodiments, the insulating layer is a ceramic material layer. The thickness of the insulating layer 40 is 1.5mm-2.5mm, for example, 1.5mm, 1.7mm, 2mm, 2.1mm, 2.3mm, or 2.5mm. By setting the thickness range of the insulating layer 40, it is avoided that the coating thickness of the insulating layer 40 is too thin, making it difficult to obtain the required electrical insulation and support strength; at the same time, it is avoided that the thickness of the insulating layer 40 is too thick, which may lead to a longer curing time for the coating layer and an increase in the overall structural thickness.

[0050] In some embodiments, the insulating layer 40 includes a color developer to distinguish whether the side coated with the insulating layer 40 is the front or back side of the positive electrode 20 through the color development effect of the color developer, including but not limited to distinguishing the areal density of the front and back sides of the positive electrode 20. The main component of the color developer may be bismuth vanadate, which is yellow in color.

[0051] The insulating layer 40 comprises a first insulating region 401 covering the first uncoated positive electrode region 28b1, a second insulating region 402 covering the positive electrode connection region 28b22, and a third insulating region 403 covering the third uncoated positive electrode region 28b2. In some embodiments, the third insulating region 403 has a first width d1 in the height direction Hd, and the second insulating region 402 has a second width d2 in the height direction Hd. In some embodiments, the first width d1 of the third insulating region 403 is smaller than the second width d2 of the second insulating region 402.

[0052] The positive electrode tabs 28b21 are all connected to the second positive electrode uncoated area 28b22. Since burrs may be generated during the cutting of the tabs, safety can be ensured by setting the first positive electrode uncoated area 28b1 and the third positive electrode uncoated area 28b3 without tabs on both sides of the winding direction Dj of the second positive electrode uncoated area 28b22. In the embodiments of this application, the first width d1 is further configured to be smaller than the second width d2. That is, an insulating layer 40 with a larger second width d2 is provided on the second positive electrode uncoated area 28b22 of the tab. This can provide support for the second positive electrode uncoated area 28b22 of the tab when bending the tab, prevent the tab from being inserted into the ground and causing risks, and make the bending corner burr-free, further improving safety.

[0053] In some embodiments, the second width d2 of the second insulating region 402 ranges from 1.3mm to 2.7mm. If the second width d2 is greater than 2.7mm, it will be too wide, resulting in an insufficient effective welding area for the tab. If the second width d2 is less than 1.3mm, it will be too small, leading to insufficient support and consequently poor safety.

[0054] The first insulating region 401 has a third width d3 in the height direction. In some embodiments, the third width d3 of the first insulating region 401 is smaller than the second width d2. An insulating layer 40 with a larger second width d2 is provided on the second positive uncoated region 28b22 of the electrode tab, which can provide support when bending the electrode tab, prevent the electrode tab from being inserted into the ground and thus prevent burrs at the bending corner, thereby improving safety.

[0055] In some embodiments, the first width d1 ranges from 1.3mm to 3.2mm. This size range ensures that the second width d2 is greater than the first width d1 without excessively occupying internal battery space.

[0056] In some embodiments, the first width d1 of the third insulating region 403 is the same as the third width d3 of the first insulating region 401 (considering process errors). The fact that the first width d1 and the third width d3 are the same allows the first insulating region 401 and the third insulating region 403 to be formed simultaneously through cutting, making processing easier.

[0057] The positive electrode tab 28b21 may include a first side Ea and a second side Eb opposite to each other in the winding direction Dj, and a third side Ec connecting the first side Ea and the second side Eb at the end away from the positive electrode connection region 28b22. The first side Ea and the second side Eb may be substantially parallel to each other. The first side Ea and the second side Eb extend away from the positive electrode connection region 28b22 and are inclined towards the winding end 10e. The second side Eb is closer to the winding end 10e than the first side Ea, so the angle between the second side Eb and the third side Ec is an acute angle. During the winding of the positive electrode 20, since the first side Ea and the second side Eb of the positive electrode tab 28b21 are inclined toward the winding end 10e, it is convenient to bend and smooth the positive electrode tab 28b21 toward the winding center hole 120c when winding the positive electrode 20. This can effectively reduce the force required to bend the positive electrode tab 28b21, thereby avoiding electrode deformation, reducing the material shedding of the positive electrode active material layer 26 of the positive electrode 20, and improving the yield.

[0058] Figure 6 This is a partial cross-sectional schematic diagram of the electrode assembly at the third insulating region 403 of the insulating layer 40. (Reference) Figure 6As shown, the separator 122 has a first end 122a in the height direction Hd, and the third insulating region 403 of the insulating layer 40 has a first end 403a in the height direction. The first end 403a of the third insulating region 403 extends beyond the first end 122a of the separator 122 in the height direction Hd. Specifically, the distance by which the first end 403a of the third insulating region 403 extends beyond the first end 122a of the separator 122 in the height direction Hd is d4. In some embodiments, the distance d4 ranges from 0.5mm to 2mm. The separator 122 extending beyond the insulating layer 40 in the height direction Hd can prevent positive electrode misalignment and other situations under vibration conditions, thereby improving battery safety.

[0059] The above describes an embodiment of this application with an insulating layer disposed on the positive electrode. However, in other embodiments, the various embodiments of the insulating layer of this application can also be applied to the negative electrode.

[0060] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A secondary battery, characterized in that, include: The electrode assembly includes a first electrode, a second electrode, and a diaphragm disposed between the first electrode and the second electrode. The first electrode includes a first current collector and a first active material layer. Along the height direction of the electrode assembly, the first current collector includes a coated area covered by the first active material layer and an uncoated area not covered by the first active material layer. Along the winding direction of the first electrode, the uncoated area sequentially includes a first uncoated area, a second uncoated area, and a third uncoated area. Along the opposite direction of the height direction, the second uncoated area includes a first electrode tab and a connecting area between the first electrode tab and the coated area. Neither the first uncoated area nor the third uncoated area includes the first electrode tab. as well as The insulating layer includes a first insulating region covering the first uncoated area, a second insulating region covering the connection area, and a third insulating region covering the third uncoated area. Wherein, the first width of the third insulating region in the height direction is smaller than the second width of the second insulating region in the height direction.

2. The secondary battery according to claim 1, characterized in that, The second width ranges from 1.3mm to 2.7mm.

3. The secondary battery according to claim 1, characterized in that, The first insulating region has a third width in the height direction, the third width being smaller than the second width.

4. The secondary battery according to claim 3, characterized in that, The first width ranges from 1.3mm to 3.2mm, and the first width is consistent with the third width.

5. The secondary battery according to claim 3, characterized in that, The diaphragm has a first end in the height direction, the third insulating region has a first end in the height direction, and the distance by which the first end of the diaphragm extends beyond the first end of the third insulating region in the height direction is in the range of 0.5mm-2mm.

6. The secondary battery according to claim 1, characterized in that, The first electrode tab includes a first side and a second side opposite to each other in the winding direction, the first side and the second side being connected to the connection area, and the first electrode extending from the beginning of the winding to the end of the winding in the winding direction, wherein the first side and the second side are inclined toward the end of the winding.

7. The secondary battery according to claim 1, characterized in that, The first electrode is a positive electrode, and the secondary battery is a cylindrical battery.

8. The secondary battery according to claim 1, characterized in that, Also includes: A housing for accommodating the electrode assembly, the housing including a peripheral sidewall and an end wall connected to one end of the peripheral sidewall, the other end of the peripheral sidewall having an opening, wherein the first electrode tab faces the end wall; The electrode post passes through the end wall and is electrically isolated from the end wall; The first collector plate is connected between the first tab and the pole post.

9. A battery pack, characterized in that, Includes the secondary battery as described in any one of claims 1-8.

10. An electronic device, characterized in that, Includes the battery pack as described in claim 9.

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