Secondary battery and electronic device

Abstract

The invention provides a secondary battery and an electronic device. The secondary battery includes an electrode assembly, a packaging bag, a first tab, and a second tab. The packaging bag comprises a main body part and a top sealing part. One end of the first tab is connected with the electrode assembly, and the other end extends out of the top sealing part; the second tab comprises a first body part and a first extension part; one end of the first body part is connected with the electrode assembly, the other end extends out of the top sealing part, and the first body part and the first tab are arranged at intervals in the first direction. The first extending part and the top sealing part are at least partially overlapped in the thickness direction of the top sealing part. The size of the first extending part is smaller than that of the first body part in the extending direction of the top sealing part. In the first direction, the first extension part is connected to one side, close to the first tab, of the first body part, and the first extension part and the first tab are arranged at an interval; and the top sealing part comprises a first sealing area positioned between the first extension part and the first tab, so that the hot box test passing rate of the secondary battery is improved, and the safety performance of the secondary battery is further improved.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to a secondary battery and an electronic device. Background Art

[0002] The packaging bag of soft-pack batteries is usually made of aluminum-plastic film or steel-plastic film. When the battery is in a high-temperature environment, the internal pressure of the packaging bag increases and swells. The top seal of the existing packaging bag is difficult to open in time to release the pressure, resulting in reduced safety performance of the battery. Summary of the invention

[0003] In view of the above situation, the present application provides a secondary battery, which is beneficial to improving safety performance.

[0004] An embodiment of the present application provides a secondary battery, the secondary battery comprising an electrode assembly, a packaging bag, a first pole tab and a second pole tab. The packaging bag comprises a main body and a top seal, and the electrode assembly is arranged in the main body. One end of the first pole tab is connected to the electrode assembly, and the other end of the first pole tab extends out of the packaging bag from the top seal. The second pole tab comprises a first main body and a first extension. One end of the first main body is connected to the electrode assembly, and the other end of the first main body extends out of the packaging bag from the top seal, and the first main body and the first pole tab are arranged at intervals along a first direction. Along the thickness direction of the top seal, the first extension overlaps the top seal at least partially. Along the extension direction of the top seal, the size of the first extension is smaller than the size of the first main body. Along the first direction, the first extension is connected to a side of the first main body close to the first pole tab, and the first extension is arranged at intervals from the first pole tab. The top seal comprises a first sealing area, and the first sealing area is located between the first extension and the first pole tab.

[0005] In the above-mentioned secondary battery, along the thickness direction of the top seal, the first extension part and the top seal part at least partially overlap. Along the extension direction of the top seal, the size of the first extension part is smaller than the size of the first main body part, so as to save the space of the head of the secondary battery and save the material cost of the second pole ear. Along the first direction, the first extension part is connected to the side of the first main body part close to the first pole ear, the first extension part and the first pole ear are arranged at intervals, and the first sealing area is located between the first extension part and the first pole ear. The first extension part can achieve the role of rigid support, so that the first sealing area is more likely to deform under stress than the part of the top seal part where the first extension part is provided. When the internal pressure of the packaging bag increases and bulges, the part of the top seal part where the first pole ear, the first main body part and the first extension part are not easy to deform compared with the first sealing area. The stress generated by the increase in the internal pressure of the packaging bag will be concentrated in the first sealing area. The first sealing area can be opened and released in time under the action of stress, thereby improving the safety performance of the secondary battery.

[0006] In some embodiments of the present application, along the first direction, the distance between the first pole ear and the first main body is W1, the length of the first sealing area is D1, 2mm≤D1≤0.4W1, so as to improve the stability of the package and facilitate stress concentration in the first sealing area so that it can be opened and pressure released in time.

[0007] In some embodiments of the present application, the first extension portion is spaced apart from the electrode assembly to improve the structural stability of the secondary battery.

[0008] In some embodiments of the present application, the first extension portion does not extend beyond the first main body portion to improve the structural stability of the secondary battery.

[0009] In some embodiments of the present application, the second pole ear includes a second extension portion, and along the thickness direction of the top seal portion, the second extension portion at least partially overlaps with the top seal portion. Along the first direction, the second extension portion is connected to the side of the first main body portion away from the first pole ear. The second extension portion can achieve the role of rigid support, so that the first sealing area is more likely to deform under stress than the part of the top seal portion where the second extension portion is provided. The second extension portion is used to optimize the stress distribution. The stress generated by the increase in the internal pressure of the packaging bag will be concentrated in the first sealing area. The first sealing area can be opened and depressurized in time under the action of stress, thereby improving the safety performance of the secondary battery.

[0010] In some embodiments of the present application, the top seal portion includes a first side edge, and along the first direction, the first side edge is located on a side of the second pole ear away from the first pole ear. The spacing between the first side edge and the first body portion is W2, and the spacing between the second extension portion and the first side edge is W3, 2mm≤W3≤0.4W2, which is beneficial to improving the structural stability of the secondary battery and can optimize the stress distribution, so that the first sealing area can generate stress concentration and can be opened and depressurized in time.

[0011] In some embodiments of the present application, both ends of the first extension portion extend out of the top seal portion, which is beneficial to improving the supporting force of the first extension portion for the top seal portion, enhancing the top seal strength, and concentrating the stress.

[0012] In some embodiments of the present application, both ends of the second extension portion extend out of the top seal portion, which is beneficial to improving the supporting force of the second extension portion for the top seal portion, enhancing the top seal strength, and concentrating the stress.

[0013] In some embodiments of the present application, along the extension direction of the top seal portion, the width of the top seal portion is H1, the first extension portion is H2, H1≤H2≤2H1, so as to improve the structural strength of the first extension portion and also help to improve the structural stability of the secondary battery.

[0014] In some embodiments of the present application, along the extension direction of the top seal portion, the width of the top seal portion is H1, the width of the second extension portion is H3, and H1≤H3≤2H1, so as to improve the structural strength of the second extension portion and also help to improve the structural stability of the secondary battery.

[0015] In some embodiments of the present application, the first pole ear includes a second body portion and a third extension portion. One end of the second body portion is connected to the electrode assembly, and the other end of the second body portion extends out of the packaging bag from the top seal portion. Along the thickness direction of the top seal portion, the third extension portion overlaps the top seal portion at least partially. Along the first direction, the third extension portion is connected to the side of the second body portion close to the second pole ear, the third extension portion is spaced from the first extension portion, and the first seal area is located between the third extension portion and the first extension portion. The third extension portion can achieve the role of rigid support, so that the first seal area is more likely to deform under stress than the portion of the top seal portion provided with the third extension portion. When the internal pressure of the packaging bag increases and bulges, the portion of the top seal portion provided with the second body portion, the third extension portion, the first body portion and the first extension portion is less likely to deform than the first seal area, and the stress generated by the increase in the internal pressure of the packaging bag will be concentrated in the first seal area, and the first seal area can be opened and released in time under the action of stress, thereby improving the safety performance of the secondary battery.

[0016] In some embodiments of the present application, the first pole ear includes a second main body and a fourth extension. One end of the second main body is connected to the electrode assembly, and the other end of the second main body extends out of the packaging bag from the top seal. Along the thickness direction of the top seal, the fourth extension at least partially overlaps with the top seal. Along the first direction, the fourth extension is connected to the side of the second main body away from the second pole ear, the second main body and the first extension are spaced apart, and the first sealing area is located between the second main body and the first extension. The fourth extension can achieve the role of rigid support, so that the first sealing area is more likely to deform under stress than the part of the top seal where the fourth extension is provided. The fourth extension is used to optimize the stress distribution. The stress generated by the increase in the internal pressure of the packaging bag will be concentrated in the first sealing area. The first sealing area can be opened and depressurized in time under the action of stress, thereby improving the safety performance of the secondary battery.

[0017] In some embodiments of the present application, the top seal portion includes a second side edge, and along the first direction, the second side edge is located on a side of the first pole ear away from the second pole ear. The spacing between the second side edge and the second body portion is W4, and the spacing between the fourth extension portion and the second side edge is W5, 2mm≤W5≤0.4W4, which is beneficial to improving the structural stability of the secondary battery and can optimize the stress distribution, so that the first sealing area can generate stress concentration and can be opened and depressurized in time.

[0018] In some embodiments of the present application, the first pole ear includes a fourth extension portion. Along the thickness direction of the top seal portion, the fourth extension portion overlaps at least partially with the top seal portion, and along the first direction, the fourth extension portion is connected to the side of the second body portion away from the second pole ear. The first extension portion, the second extension portion, the third extension portion, and the fourth extension portion are used to optimize stress distribution. The stress generated by the increase in the internal pressure of the packaging bag will be concentrated in the first sealing area. Under the action of stress, the first sealing area can be opened and depressurized in time, thereby improving the safety performance of the secondary battery.

[0019] In some embodiments of the present application, both ends of the third extension portion extend out of the top seal portion, which is beneficial to improving the supporting force of the third extension portion for the top seal portion, enhancing the top seal strength, and concentrating the stress.

[0020] In some embodiments of the present application, both ends of the fourth extension portion extend out of the top seal portion, which is beneficial to improving the supporting force of the fourth extension portion for the top seal portion, enhancing the top seal strength, and concentrating the stress.

[0021] In some embodiments of the present application, along the extension direction of the top seal portion, the width of the top seal portion is H1, the width of the third extension portion is H4, H1≤H4≤2H1, so as to improve the structural strength of the third extension portion and also help to improve the structural stability of the secondary battery.

[0022] In some embodiments of the present application, along the extension direction of the top seal portion, the width of the top seal portion is H1, the width of the fourth extension portion is H5, H1≤H5≤2H1, so as to improve the structural strength of the fourth extension portion and also help to improve the structural stability of the secondary battery.

[0023] In some embodiments of the present application, the secondary battery includes a first pole ear glue, which at least wraps the surface of the first pole ear located in the top seal portion, which is beneficial to improving the packaging strength of the top seal portion and reducing the risk of short circuit caused by contact between the first pole ear and the metal layer in the packaging film.

[0024] In some embodiments of the present application, the secondary battery includes a second pole ear glue, which at least wraps the surface of the second pole ear located in the top seal portion, which is beneficial to improving the packaging strength of the top seal portion and reducing the risk of short circuit caused by contact between the second pole ear and the metal layer in the packaging film.

[0025] In some embodiments of the present application, the first electrode tab is a negative electrode tab, and the second electrode tab is a positive electrode tab.

[0026] An embodiment of the present application further provides an electronic device, which includes any one of the secondary batteries in the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1It is a structural schematic diagram of a second battery having a first extension portion of a first size in an embodiment of the present application.

[0028] Figure 2 It is a schematic structural diagram of a top sealing portion of a secondary battery in one embodiment of the present application.

[0029] Figure 3 It is a schematic structural diagram of a second battery having a first extension portion of a second size in an embodiment of the present application.

[0030] Figure 4 It is a schematic structural diagram of a second extension portion of a secondary battery in an embodiment of the present application.

[0031] Figure 5 It is a schematic structural diagram of a third extension portion of a secondary battery in an embodiment of the present application.

[0032] Figure 6 It is a schematic structural diagram of a fourth extension portion of a secondary battery in an embodiment of the present application.

[0033] Figure 7 It is a schematic diagram of the structure of a secondary battery in one embodiment of the present application.

[0034] Figure 8 It is a schematic diagram of the structure of an electronic device in one embodiment of the present application.

[0035] Main component symbols Secondary batteries 100A, 100B, 100C, 100D, 100E Electronic device 200 Electrode assembly 10 Packaging bag 20 Packaging film 20A Molten layer 201 Metal layer 202 Nylon layer 203 Main body 21 Top wall 211 Top seal 22 First Seal Area 22A The first side 221 The second side 222 First tab 30 Second body portion 31 The third extension portion 32 Fourth extension portion 33 Second pole ear 40 First body part 41 The first extension portion 42 The second extension portion 43 First ear glue 50 Second ear glue 60 First direction X The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0037] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be a centrally disposed element at the same time. When an element is considered to be "disposed" on another element, it may be directly disposed on the other element or there may be a centrally disposed element at the same time.

[0038] When a value is considered to be "equal" to another value, it means that the two are equal within the set deviation, and the set deviation range is within 5%. In other words, when at least one of the two values ​​fluctuates within the set deviation range, even if their values ​​are not equal, they are still judged to be roughly equal. When a value is considered to have a ratio of "1:1" to another value, it means that the two are equal within the set deviation, and the set deviation range is within 5%. In other words, when at least one of the two values ​​fluctuates within the set deviation range, even if their values ​​are not equal, they are still judged to be equal in ratio.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items. The term "overlap" used herein refers to the overlap of the projections of two parts or the overlap of the projections of two parts.

[0040] An embodiment of the present application provides a secondary battery, the secondary battery comprising an electrode assembly, a packaging bag, a first pole tab and a second pole tab. The packaging bag comprises a main body and a top seal, and the electrode assembly is arranged in the main body. One end of the first pole tab is connected to the electrode assembly, and the other end of the first pole tab extends out of the packaging bag from the top seal. The second pole tab comprises a first main body and a first extension. One end of the first main body is connected to the electrode assembly, and the other end of the first main body extends out of the packaging bag from the top seal, and the first main body and the first pole tab are arranged at intervals along a first direction. Along the thickness direction of the top seal, the first extension overlaps the top seal at least partially. Along the extension direction of the top seal, the size of the first extension is smaller than the size of the first main body. Along the first direction, the first extension is connected to a side of the first main body close to the first pole tab, and the first extension is arranged at intervals from the first pole tab. The top seal comprises a first sealing area, and the first sealing area is located between the first extension and the first pole tab.

[0041] In the above-mentioned secondary battery, along the thickness direction of the top seal, the first extension part and the top seal part at least partially overlap. Along the extension direction of the top seal, the size of the first extension part is smaller than the size of the first main body part, so as to save the space of the head of the secondary battery and save the material cost of the second pole ear. Along the first direction, the first extension part is connected to the side of the first main body part close to the first pole ear, the first extension part and the first pole ear are arranged at intervals, and the first sealing area is located between the first extension part and the first pole ear. The first extension part can achieve the role of rigid support, so that the first sealing area is more likely to deform under stress than the part of the top seal part where the first extension part is provided. When the internal pressure of the packaging bag increases and bulges, the part of the top seal part where the first pole ear, the first main body part and the first extension part are not easy to deform compared with the first sealing area. The stress generated by the increase in the internal pressure of the packaging bag will be concentrated in the first sealing area. The first sealing area can be opened and released in time under the action of stress, thereby improving the safety performance of the secondary battery.

[0042] The embodiments of the present application are further described below in conjunction with the accompanying drawings.

[0043] Example 1 Please also read Figure 1 and Figure 2 One embodiment of the present application provides a secondary battery 100A. The secondary battery 100A refers to a battery that can be used continuously by activating active materials through charging after discharge.

[0044] The secondary battery 100A includes an electrode assembly 10, a packaging bag 20, a first pole tab 30 and a second pole tab 40. The electrode assembly 10 is formed by winding or stacking a positive electrode sheet, a separator and a negative electrode sheet arranged in sequence. The electrode assembly 10 is used to convert chemical energy into electrical energy. The polarity of the first pole tab 30 is opposite to the polarity of the second pole tab 40. Optionally, the first pole tab 30 is a negative pole tab and the second pole tab 40 is a positive pole tab; or the first pole tab 30 is a positive pole tab and the second pole tab 40 is a negative pole tab.

[0045] The packaging bag 20 includes a main body 21 and a top seal 22 connected to the main body 21. Specifically, the packaging bag 20 is made of a packaging film 20A, the main body 21 refers to the part of the packaging film 20A where the punch holes are set, and the top seal 22 refers to the part where the packaging film 20A overlaps and joins. The electrode assembly 10 is arranged in the main body 21, and the top seal 22 is used to seal the main body 21 at the position corresponding to the head of the secondary battery 100A, that is, the position where the first pole tab 30 and the second pole tab 40 extend.

[0046] Specifically, the main body 21 includes a top wall 211, and the top sealing portion 22 is connected to the top wall 211. The top sealing portion 22 extends in a direction perpendicular to the top wall 211, or the top sealing portion 22 is bent toward the top wall 211. This application takes the way that the top sealing portion 22 extends in a direction perpendicular to the top wall 211 as an example for description.

[0047] One end of the first electrode tab 30 is connected to the electrode assembly 10 , and the other end of the first electrode tab 30 extends out of the packaging bag 20 from the top seal portion 22 .

[0048] Please continue reading Figure 1 and Figure 2 The second electrode tab 40 includes a first body portion 41 and a first extension portion 42. One end of the first body portion 41 is connected to the electrode assembly 10, and the other end of the first body portion 41 extends out of the packaging bag 20 from the top seal portion 22. The first body portion 41 and the first electrode tab 30 are spaced apart along the first direction X. The first electrode tab 30 and the first body portion 41 are configured to be connected to an external circuit to form a complete current loop.

[0049] Along the thickness direction of the top seal portion 22, the first extension portion 42 at least partially overlaps with the top seal portion 22. Along the extension direction of the top seal portion 22, the size of the first extension portion 42 is smaller than the size of the first body portion 41, so as to save space at the head of the secondary battery 100A and save the material cost of the second tab 40.

[0050] Along the first direction X, the first extension portion 42 is connected to a side of the first body portion 41 close to the first pole tab 30, and the first extension portion 42 is spaced apart from the first pole tab 30. The top seal portion 22 includes a first sealing area 22A, and along the first direction X, the first sealing area 22A is located between the first extension portion 42 and the first pole tab 30. The first extension portion 42 can achieve a rigid support function, so that the first sealing area 22A is more likely to deform under stress than the portion of the top seal portion 22 where the first extension portion 42 is provided.

[0051] In the above-mentioned secondary battery 100A, when the internal pressure of the packaging bag 20 increases and swells, the top seal portion 22 having the first pole ear 30, the first main body portion 41 and the first extension portion 42 is less likely to deform than the first sealing area 22A. The stress generated by the increased internal pressure of the packaging bag 20 will be concentrated in the first sealing area 22A. Under the action of the stress, the first sealing area 22A can be opened and released in time to improve the safety performance of the secondary battery 100A.

[0052] Please also read Figure 1 and Figure 3 In some embodiments, the first extension portion 42 is separated from the electrode assembly 10 to reduce the risk of interference between the first extension portion 42 and the electrode assembly 10 and improve the structural stability of the secondary battery 100A.

[0053] In some embodiments, the first extension portion 42 does not extend beyond the first body portion 41 to reduce the risk of interference between the first extension portion 42 and electronic components of the circuit board assembly on the top wall 211 , thereby improving the structural stability of the secondary battery 100A.

[0054] Please continue reading Figure 1 and Figure 2 In some embodiments, along the thickness direction of the packaging film 20A, the packaging film 20A includes a melting layer 201, a metal layer 202, and a nylon layer 203 which are sequentially stacked from the inside to the outside. The melting layer 201 includes polypropylene, and the melting layer 201 will melt at a preset temperature and have viscosity to facilitate the packaging of the packaging bag 20. In addition, the melting layer 201 can reduce the risk of the metal layer 202 being corroded by a solvent (such as an electrolyte). The metal layer 202 includes aluminum, and the metal layer 202 is used to reduce the risk of water vapor penetrating into the interior of the packaging bag 20 and to improve the structural strength of the packaging bag 20. Specifically, the aluminum material reacts with oxygen in the air to form a dense oxide film to isolate water vapor. The nylon layer 203 includes nylon, and the nylon layer 203 is used to resist external physical impact.

[0055] In some embodiments, the top seal portion 22 includes two packaging films 20A, the melting layers 201 of the two packaging films 20A are connected to each other, and the first electrode tab 30 , the first extension portion 42 and the second extension portion 43 are disposed between the two melting layers 201 .

[0056] In some embodiments, the first pole tab 30 and the second pole tab 40 are respectively made of metal materials to have good conductivity and improve structural strength. Optionally, the metal material includes at least one of aluminum, aluminum alloy, copper, copper alloy, nickel, nickel alloy or copper-plated nickel.

[0057] In some embodiments, the first body portion 41 and the first extension portion 42 are integrally provided to improve the structural stability of the second electrode tab 40 .

[0058] Please continue reading Figure 1 and Figure 2 In some embodiments, the secondary battery 100A further includes a first pole ear glue 50, and the first pole ear 30 is connected to the top seal portion 22 through the first pole ear glue 50, which is beneficial to improve the packaging strength of the top seal portion 22 and reduce the risk of short circuit caused by the first pole ear 30 contacting the metal layer 202 in the packaging film 20A. Specifically, the first pole ear glue 50 at least wraps the surface of the first pole ear 30 located in the top seal portion 22, and the first pole ear glue 50 is melt-connected with the melting layer 201 of the two layers of the packaging film 20A of the top seal portion 22.

[0059] Optionally, the first tab glue 50 includes at least one of polypropylene, polyethylene, and polyethylene terephthalate.

[0060] In some embodiments, the secondary battery 100A further includes a second pole ear glue 60, and the second pole ear 40 is connected to the top seal portion 22 through the second pole ear glue 60, which is beneficial to improve the packaging strength of the top seal portion 22 and reduce the risk of short circuit caused by the second pole ear 40 contacting the metal layer 202 in the packaging film 20A. Specifically, the second pole ear glue 60 at least wraps the surface of the first body portion 41 and the first extension portion 42 located in the top seal portion 22, and the second pole ear glue 60 is melt-connected with the melting layer 201 of the two layers of the packaging film 20A of the top seal portion 22.

[0061] Optionally, the second tab glue 60 includes at least one of polypropylene, polyethylene, and polyethylene terephthalate.

[0062] Please continue reading Figure 1 In some embodiments, along the first direction X, the spacing between the first pole ear 30 and the first main body 41 is W1, the length of the first sealing area 22A is D1, and 2mm≤D1≤0.4W1. When D1 is too small (less than 2mm), it is easy to cause the molten layer to flow and overflow when the top seal 22 is heat-sealed. When D1 is too large (greater than 0.4W1), it is easy to disperse the stress of the first sealing area 22A. By limiting 2mm≤D1≤0.4W1, the stability of the package is improved, and it is convenient for the first sealing area 22A to generate stress concentration and be able to be opened and depressurized in time.

[0063] Optionally, L1 is one of 0.1W1, 0.2W1, 0.3W1, 0.4W1 and any other value in the range of 2mm≤D1≤0.4W1.

[0064] It should be noted that L1 is measured in the following manner: observing along the thickness direction of the top seal portion 22, selecting three measuring points on the side of the first main body portion 41 close to the first pole lug 30 along the first direction X, measuring the spacing value between each measuring point and the side of the first pole lug 30 close to the second pole lug 40 along the first direction X, and calculating the average value of the three spacing values, which is L1.

[0065] Please continue reading Figure 1 In some embodiments, along the extension direction of the top seal portion 22, the width of the top seal portion 22 is H1, the width of the first extension portion 42 is H2, and H1≤H2≤2H1. When H22H1, the first extension portion 42 is likely to interfere with the electrode assembly 10 or the electronic components of the circuit board assembly located on the top wall 211. By limiting H1≤H2≤2H1, the structural strength of the first extension portion 42 is improved, and it is also beneficial to improve the structural stability of the secondary battery 100A.<h1>

[0066] Optionally, H2 is one of H1, 1.1H1, 1.2H1, 1.3H1, 1.4H1, 1.5H1, 1.6H1, 1.7H1, 1.8H1, 1.9H1, 2H1 and any other value in the range of H1≤H2≤2H1.

[0067] It should be noted that H1 is measured in the following manner: along the extension direction of the top seal portion 22, three measuring points are selected on the side of the top seal portion 22 away from the top wall 211, and the width value of each measuring point and the side of the top seal portion 22 close to the top wall 211 along the extension direction of the top seal portion 22 is measured, and the average value of the three width values ​​is calculated, and the average value is H1. H2 is measured in the following manner: along the extension direction of the first extension portion 42, three measuring points are selected on the side of the first extension portion 42 away from the electrode assembly 10, and the width value of each measuring point and the side of the first extension portion 42 close to the electrode assembly 10 along the extension direction of the first extension portion 42 is measured, and the average value of the three width values ​​is calculated, and the average value is H2.

[0068] In some embodiments, along the extension direction of the first extension portion 42, the side of the first extension portion 42 close to the electrode assembly 10 is located inside the main body 21, and the side of the first extension portion 42 away from the electrode assembly 10 is located outside the top sealing portion 22, so as to improve the supporting stability of the first extension portion 42 on the top sealing portion 22.

[0069] Example 2 See also Figure 4 One embodiment of the present application further provides a secondary battery 100B. The difference between the secondary battery 100B and the secondary battery 100A is that: The second pole tab 40 includes a second extension portion 43, and along the thickness direction of the top seal portion 22, the second extension portion 43 at least partially overlaps with the top seal portion 22. Along the extension direction of the top seal portion 22, the size of the second extension portion 43 is smaller than the size of the first body portion 41, so as to save space at the head of the secondary battery 100B and help save the material cost of the second pole tab 40.

[0070] Along the first direction Z, the second extension portion 43 is connected to the side of the first main body portion 41 away from the first pole tab 30. The second extension portion 43 can realize the role of rigid support, so that the first sealing area 22A is more likely to deform under stress than the part of the top seal portion 22 where the second extension portion 43 is provided. The second extension portion 43 is used to optimize the stress distribution. The stress generated by the increase in the internal pressure of the packaging bag 20 will be concentrated in the first sealing area 22A. The first sealing area 22A can be opened and released in time under the action of stress, thereby improving the safety performance of the secondary battery 100B.

[0071] Please continue reading Figure 4 In some embodiments, the second extension portion 43 is separated from the electrode assembly 10 to reduce the risk of interference between the second extension portion 43 and the electrode assembly 10 and improve the structural stability of the secondary battery 100B.

[0072] In some embodiments, the second extension portion 43 does not extend beyond the first body portion 41 to reduce the risk of interference between the second extension portion 43 and electronic components of the circuit board assembly on the top wall 211 , thereby improving the structural stability of the secondary battery 100A.

[0073] In some embodiments, the first main body portion 41 , the first extension portion 42 , and the second extension portion 43 are integrally configured to improve the structural stability of the second electrode tab 40 .

[0074] Please continue reading Figure 4 In some embodiments, the top seal portion 22 includes a first side 221, and along the first direction X, the first side 221 is located on the side of the second pole ear 40 away from the first pole ear 30. The spacing between the first side 221 and the first main body 41 is W2, and the spacing between the second extension portion 43 and the first side 221 is W3, 2mm≤W3≤0.4W2. When W3 is too small (less than 2mm), the second extension portion 43 is likely to interfere with the side seal structure connected to the main body 21 along the first direction X. When W3 is too large (greater than 0.4W2), it is easy to form a weak area between the second extension portion 43 and the first side 221 to disperse stress. By limiting 2mm≤W3≤0.4W 2，This is beneficial to improving the structural stability of the secondary battery 100B and can optimize stress distribution, so that the first sealing area 22A can generate stress concentration and be able to be opened and pressure released in time.

[0075] Optionally, W3 is one of 0.1W2, 0.2W2, 0.3W2, 0.4W2 and any other value in the range of 2mm≤W3≤0.4W2.

[0076] It should be noted that W2 is measured in the following manner: observing along the thickness direction of the top seal portion 22, selecting three measuring points on the first side 221, measuring the spacing value between each measuring point and the side of the first body portion 41 away from the first pole tab 30 along the first direction X, calculating the average value of the three spacing values, and the average value is W2. W3 is measured in the following manner: observing along the thickness direction of the top seal portion 22, selecting three measuring points on the first side 221, measuring the spacing value between each measuring point and the side of the second extension portion 43 away from the first body portion 41 along the first direction X, and calculating the average value of the three spacing values, and the average value is W3.

[0077] Please continue reading Figure 4 In some embodiments, along the extension direction of the top seal portion 22, the width of the top seal portion 22 is H1, the width of the second extension portion 43 is H3, and H1≤H3≤2H1. When H32H1, the second extension portion 43 is likely to interfere with the electrode assembly 10 or the electronic components of the circuit board assembly located on the top wall 211. By limiting H1≤H3≤2H1, the structural strength of the second extension portion 43 is improved, and it is also beneficial to improve the structural stability of the secondary battery 100B.<h1>

[0078] Optionally, H3 is one of H1, 1.1H1, 1.2H1, 1.3H1, 1.4H1, 1.5H1, 1.6H1, 1.7H1, 1.8H1, 1.9H1, 2H1 and any other value in the range of H1≤H3≤2H1.

[0079] It should be noted that H3 is measured in the following manner: along the extending direction of the second extension portion 43, three measuring points are selected on the side of the second extension portion 43 away from the electrode assembly 10, and the width value of each measuring point and the side of the second extension portion 43 close to the electrode assembly 10 along the extending direction of the second extension portion 43 is measured, and the average value of the three width values ​​is calculated, and the average value is H3.

[0080] In some embodiments, H3 = H2, so that the first body portion 41 is subjected to uniform force on both sides along the first direction X.

[0081] Except for the above differences, the parameters of the secondary battery 100B are substantially the same as those of the secondary battery 100A, and reference may be made to the description of the secondary battery 100A.

[0082] Example 3 See also Figure 5 One embodiment of the present application further provides a secondary battery 100C. The difference between the secondary battery 100C and the secondary battery 100B is that: The first electrode tab 30 includes a second body portion 31 and a third extension portion 32. One end of the second body portion 31 is connected to the electrode assembly 10, and the other end of the second body portion 31 extends out of the packaging bag 20 from the top seal portion 22. The second body portion 31 and the first body portion 41 are spaced apart along the first direction X. The second body portion 31 and the first body portion 41 are configured to be connected to an external circuit to form a complete current loop.

[0083] Along the thickness direction of the top seal portion 22, the third extension portion 32 at least partially overlaps with the top seal portion 22. Along the extension direction of the top seal portion 22, the size of the third extension portion 32 is smaller than the size of the second body portion 31, so as to save space at the head of the secondary battery 100C and save the material cost of the first electrode tab 30.

[0084] Along the first direction X, the third extension portion 32 is connected to a side of the second body portion 31 close to the second pole tab 40, and the third extension portion 32 is spaced apart from the first extension portion 42. The first sealing area 22A is located between the third extension portion 32 and the first extension portion 42. The third extension portion 32 can achieve a rigid support function, so that the first sealing area 22A is more likely to deform under stress than the portion of the top sealing portion 22 where the third extension portion 32 is provided.

[0085] In the above-mentioned secondary battery 100C, when the internal pressure of the packaging bag 20 increases and swells, the top seal portion 22 having the second main body portion 31, the third extension portion 32, the first main body portion 41 and the first extension portion 42 is less likely to deform than the first sealing area 22A. The stress generated by the increase in the internal pressure of the packaging bag 20 will be concentrated in the first sealing area 22A. Under the action of the stress, the first sealing area 22A can be opened and released in time to improve the safety performance of the secondary battery 100C.

[0086] Please continue reading Figure 5 In some embodiments, the third extension portion 32 is separated from the electrode assembly 10 to reduce the risk of interference between the third extension portion 32 and the electrode assembly 10 and improve the structural stability of the secondary battery 100C.

[0087] In some embodiments, the third extension portion 32 does not extend beyond the second body portion 31 to reduce the risk of interference between the third extension portion 32 and electronic components of the circuit board assembly on the top wall 211 , thereby improving the structural stability of the secondary battery 100C.

[0088] In some embodiments, the second body portion 31 and the third extension portion 32 are integrally provided to improve the structural stability of the first electrode tab 30 .

[0089] Please continue reading Figure 5 In some embodiments, along the first direction X, the distance between the third extension portion 32 and the first main body portion 41 is W1, the length of the first sealing area 22A is D1, 2mm≤D1≤0.4W1, so as to improve the stability of the package and facilitate the first sealing area 22A to generate stress concentration so that it can be opened and depressurized in time.

[0090] Along the extension direction of the top seal portion 22, the width of the top seal portion 22 is H1, and the width of the third extension portion 32 is H4, H1≤H4≤2H1. When H42H1, the third extension portion 32 is likely to interfere with the electrode assembly 10 or the electronic components of the circuit board assembly located on the top wall 211. By limiting H1≤H4≤2H1, the structural strength of the third extension portion 32 is improved, and it is also beneficial to improve the structural stability of the secondary battery 100C.<h1>

[0091] Optionally, H4 is one of H1, 1.1H1, 1.2H1, 1.3H1, 1.4H1, 1.5H1, 1.6H1, 1.7H1, 1.8H1, 1.9H1, 2H1 and any other value in the range of H1≤H4≤2H1.

[0092] It should be noted that H4 is measured in the following manner: along the extending direction of the third extension portion 32, three measuring points are selected on the side of the third extension portion 32 away from the electrode assembly 10, and the width value of each measuring point and the side of the third extension portion 32 close to the electrode assembly 10 along the extending direction of the third extension portion 32 is measured, and the average value of the three width values ​​is calculated, and the average value is H4.

[0093] In some embodiments, along the extension direction of the third extension portion 32, the side of the third extension portion 32 close to the electrode assembly 10 is located inside the main body 21, and the side of the third extension portion 32 away from the electrode assembly 10 is located outside the top sealing portion 22, so as to improve the supporting stability of the third extension portion 32 on the top sealing portion 22.

[0094] It can be understood that, in some embodiments, the second electrode tab 40 in the secondary battery 100C can be configured to have the same structure as the second electrode tab 40 in the secondary battery 100A.

[0095] Except for the above differences, the parameters of the secondary battery 100C and the secondary battery 100B are substantially the same, and reference may be made to the description of the secondary battery 100B.

[0096] Example 4 See also Figure 6 One embodiment of the present application further provides a secondary battery 100D. The difference between the secondary battery 100D and the secondary battery 100B is that: The first electrode tab 30 includes a second body portion 31 and a fourth extension portion 33. One end of the second body portion 31 is connected to the electrode assembly 10, and the other end of the second body portion 31 extends out of the packaging bag 20 from the top seal portion 22, and the second body portion 31 and the first body portion 41 are spaced apart along the first direction X. The second body portion 31 and the first body portion 41 are configured to be connected to an external circuit to form a complete current loop.

[0097] Along the thickness direction of the top seal portion 22, the fourth extension portion 33 at least partially overlaps with the top seal portion 22. Along the extension direction of the top seal portion 22, the size of the fourth extension portion 33 is smaller than the size of the second body portion 31, so as to save space at the head of the secondary battery 100D and save the material cost of the first electrode tab 30.

[0098] Along the first direction X, the fourth extension portion 33 is connected to the side of the second body portion 31 away from the second pole ear 40, the second body portion 31 and the first extension portion 42 are arranged at intervals, and the first sealing area 22A is located between the second body portion 31 and the first extension portion 42. The fourth extension portion 33 can realize the role of rigid support, so that the first sealing area 22A is more likely to deform under stress than the part of the top seal portion 22 where the fourth extension portion 33 is provided. The fourth extension portion 33 is used to optimize the stress distribution. The stress generated by the increase in the internal pressure of the packaging bag 20 will be concentrated in the first sealing area 22A. The first sealing area 22A can be opened and released in time under the action of stress, thereby improving the safety performance of the secondary battery 100D.

[0099] Please continue reading Figure 6 In some embodiments, the fourth extension portion 33 is separated from the electrode assembly 10 to reduce the risk of interference between the fourth extension portion 33 and the electrode assembly 10 and improve the structural stability of the secondary battery 100D.

[0100] In some embodiments, the fourth extension portion 33 does not extend beyond the second body portion 31 to reduce the risk of interference between the fourth extension portion 33 and electronic components of the circuit board assembly on the top wall 211 , thereby improving the structural stability of the secondary battery 100D.

[0101] In some embodiments, the second body portion 31 and the fourth extension portion 33 are integrally provided to improve the structural stability of the first electrode tab 30 .

[0102] Please continue reading Figure 6 In some embodiments, the top seal portion 22 includes a second side 222, and along the first direction X, the second side 222 is located on the side of the first pole ear 30 away from the second pole ear 40. The spacing between the second side 222 and the second main body 31 is W4, and the spacing between the fourth extension portion 33 and the second side 222 is W5, 2mm≤W5≤0.4W4. When W4 is too small (less than 2mm), the fourth extension portion 33 is likely to interfere with the side seal structure connected to the main body 21 along the first direction X. When W4 is too large (greater than 0.4W2), it is easy to form a weak area between the fourth extension portion 33 and the second side 222 to disperse stress. By limiting 2mm≤W5≤0.4W 4， This is beneficial to improving the structural stability of the secondary battery 100D and can optimize stress distribution, so that the first sealing area 22A can generate stress concentration and be able to be opened and pressure released in time.

[0103] Optionally, W5 is one of 0.1W4, 0.2W4, 0.3W4, 0.4W4 and any other value in the range of 2mm≤W5≤0.4W4.

[0104] It should be noted that W4 is measured in the following manner: observing along the thickness direction of the top seal portion 22, selecting three measuring points on the second side 222, measuring the spacing between each measuring point and the side of the second body portion 31 away from the second pole tab 40 along the first direction X, calculating the average value of the three spacing values, and the average value is W4. W5 is measured in the following manner: observing along the thickness direction of the top seal portion 22, selecting three measuring points on the second side 222, measuring the spacing between each measuring point and the side of the fourth extension portion 33 away from the second body portion 31 along the first direction X, calculating the average value of the three spacing values, and the average value is W5.

[0105] Please continue reading Figure 6 In some embodiments, along the extension direction of the top seal portion 22, the width of the top seal portion 22 is H1, the width of the fourth extension portion 33 is H5, and H1≤H5≤2H1. When H52H1, the fourth extension portion 33 is likely to interfere with the electrode assembly 10 or the electronic components of the circuit board assembly located on the top wall 211. By limiting H1≤H5≤2H1, the structural strength of the fourth extension portion 33 is improved, and it is also beneficial to improve the structural stability of the secondary battery 100D.<h1>

[0106] Optionally, H5 is one of H1, 1.1H1, 1.2H1, 1.3H1, 1.4H1, 1.5H1, 1.6H1, 1.7H1, 1.8H1, 1.9H1, 2H1 and any other value in the range of H1≤H5≤2H1.

[0107] It should be noted that H5 is measured in the following manner: along the extending direction of the fourth extension portion 33, three measuring points are selected on the side of the fourth extension portion 33 away from the electrode assembly 10, and the width value of each measuring point and the side of the fourth extension portion 33 close to the electrode assembly 10 along the extending direction of the fourth extension portion 33 is measured, and the average value of the three width values ​​is calculated, and the average value is H5.

[0108] It can be understood that, in some embodiments, the second electrode tab 40 in the secondary battery 100D can be configured to have the same structure as the second electrode tab 40 in the secondary battery 100A.

[0109] Except for the above differences, the parameters of the secondary battery 100D and the secondary battery 100B are substantially the same, and reference may be made to the description of the secondary battery 100B.

[0110] Example 5 See also Figure 7 One embodiment of the present application further provides a secondary battery 100E. The difference between the secondary battery 100E and the secondary battery 100B is that: The first electrode tab 30 includes a second body portion 31, a third extension portion 32, and a fourth extension portion 33. One end of the second body portion 31 is connected to the electrode assembly 10, and the other end of the second body portion 31 extends out of the packaging bag 20 from the top seal portion 22, and the second body portion 31 and the first body portion 41 are spaced apart along the first direction X. The second body portion 31 and the first body portion 41 are configured to be connected to an external circuit to form a complete current loop.

[0111] Along the thickness direction of the top seal portion 22, the third extension portion 32 and the fourth extension portion 33 at least partially overlap with the top seal portion 22. Along the extension direction of the top seal portion 22, the size of the second extension portion 43 is smaller than the size of the first body portion 41, and the size of the fourth extension portion 33 is smaller than the size of the second body portion 31, so as to save space at the head of the secondary battery 100B and help save the material cost of the second tab 40.

[0112] Along the first direction X, the third extension portion 32 is connected to the side of the second body portion 31 close to the second pole ear 40, and the third extension portion 32 is spaced apart from the first extension portion 42. The first sealing area 22A is located between the third extension portion 32 and the first extension portion 42. The fourth extension portion 33 is connected to the side of the second body portion 31 away from the second pole ear 40. The first extension portion 42, the second extension portion 43, the third extension portion 32 and the fourth extension portion 33 are used to optimize the stress distribution. The stress generated by the increase in the internal pressure of the packaging bag 20 will be concentrated in the first sealing area 22A. The first sealing area 22A can be opened and released in time under the action of the stress, thereby improving the safety performance of the secondary battery 100E.

[0113] It should be noted that the parameters of the third extending portion 32 of the secondary battery 100E and the third extending portion 32 of the secondary battery 100C are substantially the same, and the parameters of the fourth extending portion 33 of the secondary battery 100E and the fourth extending portion 33 of the secondary battery 100D are substantially the same.

[0114] In some embodiments, H5=H4, so that the second body portion 31 is subjected to uniform force on both sides along the first direction X.

[0115] It can be understood that, in some embodiments, the second electrode tab 40 in the secondary battery 100E can be configured to have the same structure as the second electrode tab 40 in the secondary battery 100A.

[0116] Except for the above differences, the parameters of the secondary battery 100E and the secondary battery 100B are substantially the same, and reference may be made to the description of the secondary battery 100B.

[0117] See also Figure 8 In some embodiments, an embodiment of the present application further provides an electronic device 200. The electronic device 200 includes the secondary battery (100A, 100B, 100C, 100D, 100E) in any of the above embodiments. The electronic device 200 can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc.

[0118] In the secondary battery (100A, 100B, 100C, 100D, 100E) and the electronic device 200, the first extension portion 42 at least partially overlaps the top seal portion 22 along the thickness direction of the top seal portion 22. Along the first direction X, the first extension portion 42 is connected to the side of the first body portion 41 close to the first pole tab 30, the first extension portion 42 is spaced apart from the first pole tab 30, and the first sealing area 22A is located between the first extension portion 42 and the first pole tab 30. The first extension portion 42 can achieve the role of rigid support, so that the first sealing area 22A is more likely to deform under stress than the portion of the top seal portion 22 where the first extension portion 42 is provided. When the internal pressure of the packaging bag 20 increases and bulges, the top seal portion 22 provided with the first pole ear 30, the first main body portion 41 and the first extension portion 42 is less likely to deform than the first sealing area 22A. The stress generated by the increased internal pressure of the packaging bag 20 will be concentrated in the first sealing area 22A. Under the action of the stress, the first sealing area 22A can be opened and released in time to improve the safety performance of the secondary battery (100A, 100B, 100C, 100D, 100E).

[0119] The specific implementation of the secondary battery in the examples and comparative examples is described below.

[0120] 1. Secondary battery hot box test: First, the secondary battery to be tested is pretreated. The pretreatment conditions are as follows: after standing at a test temperature of 20℃ (±5℃) for 60 minutes, discharge to 3.0V with a constant current of 0.7C and stand for 10 minutes; then charge to 4.25V with a constant current of 0.5C, and then charge to 0.05C with a constant voltage of 4.25V. After the pretreatment is completed, the secondary battery is placed vertically in a hot box for hot box testing, in which the temperature in the hot box is raised to 130±2℃ at 5±2℃ / min and maintained for 60 minutes. During the test, if the secondary battery does not burn or explode, it means that the hot box test has passed, otherwise, the hot box test has failed. 100 secondary batteries were tested, and the number of cells that passed the test was X, and the test pass rate was X / 100.

[0121] Embodiment 1: A secondary battery with an initial thickness of 4.8 mm, a length of 87 mm, and a width of 64 mm at 50% SOC. The assembly process is as follows: (1) Preparation of negative electrode sheet: Mix the negative electrode active materials artificial graphite, conductive carbon black (Super P), and styrene-butadiene rubber (SBR) in a weight ratio of 96:1.5:2.5, add deionized water as a solvent, prepare a slurry with a weight percentage of 50wt%, and stir evenly. The slurry is evenly coated on one surface of the copper foil, and then dried at 110°C to obtain a negative electrode sheet coated with a negative electrode active material layer on one side. When preparing a double-sided coated negative electrode sheet, repeat the above steps on the other surface of the negative electrode sheet to obtain a negative electrode sheet coated with a negative electrode active material layer on both sides. Then the coated electrode sheet is cold pressed to a thickness of 105mm, and the negative electrode tab is welded on the copper foil at the edge of the negative electrode sheet. The structure of the negative electrode tab is shown in Table 1, and the material of the negative electrode tab is copper.

[0122] (2) Preparation of positive electrode sheet: The positive electrode active material lithium cobalt oxide (LiCoO2), conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) are mixed in a weight ratio of 97.5:1.0:1.5, and N-methylpyrrolidone (NMP) is added as a solvent to prepare a slurry with a solid content of 75wt%, and stirred evenly. The slurry is evenly coated on one surface of the aluminum foil, and then dried at 90°C to obtain a positive electrode sheet coated with positive electrode active material on one side. When preparing a double-sided coated positive electrode sheet, repeat the above coating steps on the other surface of the aluminum foil. Then the coated electrode sheet is cold pressed to a thickness of 95mm, and the positive electrode ear is welded on the aluminum foil at the edge of the positive electrode sheet. The structure of the positive electrode ear is shown in Table 1, and the material of the positive electrode ear is aluminum.

[0123] (3) Preparation of electrolyte: In a dry argon atmosphere, ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) were first mixed in a mass ratio of EC:EMC:DEC = 30:50:20 to form a basic organic solvent. Then, lithium salt lithium hexafluorophosphate (LiPF6) was added to the basic organic solvent to dissolve and mix well to obtain an electrolyte with a lithium salt concentration of 1.15 mol / L.

[0124] (4) Preparation of diaphragm: A three-layer diaphragm is used, which includes a stacked adhesive layer, a substrate layer and an adhesive layer. The first substrate layer is made of polyethylene (PE), the adhesive in the adhesive layer is PVDF, and the adhesive layer also contains inorganic particles of boehmite.

[0125] (5) Preparation of electrode assembly: winding the positive electrode sheet, separator and negative electrode sheet.

[0126] (6) Assembly of electrode assembly: Place the aluminum-plastic film with a dent in the assembly fixture, with the dent facing upward, place the electrode assembly in the dent, and apply external force to compress it. Then cover the electrode assembly with another aluminum-plastic film with a dent facing downward, and heat-seal the two aluminum-plastic films around by hot pressing to obtain an assembled electrode assembly. Among them, the positive electrode tab has a first extension portion, but not a second extension portion, and the negative electrode tab does not have a third extension portion and a fourth extension portion. The first sealing area D1 is 2 mm. Along the extension direction of the top seal portion, the width of the top seal portion is H1, and the width of the first extension portion is H2, H2 / H1=2. The spacing between the first tab and the second tab is W1, W1=20 mm.

[0127] (7) Liquid injection packaging: The electrolyte is injected into the assembled electrode assembly, and after vacuum packaging, static standing, hot pressing, shaping and other processes, a secondary battery is produced.

[0128] Comparative Example 1: Conventional tabs are used for both the positive and negative tabs. It should be noted that the parameters of Comparative Example 1 are the same as those of Example 1 except for the structures of the positive and negative tabs.

[0129] It can be seen from Comparative Example 1 and Examples 1-5 that the passing rate of the hot box test of the secondary battery can be improved by providing the first extension portion on the second electrode tab (positive electrode tab).

[0130] It can be seen from Examples 1-2 that by providing the first extension portion and the second extension portion on the second electrode tab (positive electrode tab), the passing rate of the hot box test of the secondary battery can be further improved.

[0131] It can be seen from Examples 3-5 that by providing the fourth extension portion on the first electrode tab (negative electrode tab), the passing rate of the hot box test of the secondary battery can be further improved.

[0132] It can be seen from Examples 4 and 6-9 that the passing rate of the hot box test of secondary batteries can be improved by satisfying 2mm≤D1≤0.4W1.

[0133] It can be seen from Examples 4 and 10-12 that 2mm≤W3≤0.4W2 can improve the pass rate of the secondary battery hot box test. It should be noted that when W3<2mm, the second extension portion is likely to interfere with the side seal portion connected to the main body in the first direction, so an embodiment with W3<2mm is not provided.

[0134] It can be seen from Examples 4, 13-16 that the passing rate of the hot box test of the secondary battery can be improved by setting H1≤H2≤2H1, H1≤H3≤2H1, H1≤H4≤2H1, and H1≤H5≤2H1. It should be noted that when H2>2H1, it is easy for the second extension to interfere with the electronic components of the electrode assembly or the circuit board assembly located on the top wall.

[0135] In addition, those skilled in the art may also make other changes within the spirit of the present application. Of course, these changes made according to the spirit of the present application should be included in the scope disclosed in the present application.

Claims

1. A secondary battery, characterized in that: The secondary battery comprises: Electrode assembly; A packaging bag, the packaging bag comprising a main body and a top seal, the electrode assembly being disposed in the main body; a first electrode tab, one end of which is connected to the electrode assembly, and the other end of which extends out of the packaging bag from the top seal portion; A second electrode tab, the second electrode tab includes a first main body and a first extension portion, one end of the first main body is connected to the electrode assembly, the other end of the first main body extends out of the packaging bag from the top seal portion, the first main body and the first electrode tab are spaced apart along a first direction, along the thickness direction of the top seal portion, the first extension portion and the top seal portion at least partially overlap, along the extending direction of the top seal portion, the size of the first extension portion is smaller than the size of the first main body, along the first direction, the first extension portion is connected to a side of the first main body close to the first electrode tab, the first extension portion and the first electrode tab are spaced apart, the top seal portion includes a first sealing area, and the first sealing area is located between the first extension portion and the first electrode tab.

2. The secondary battery according to claim 1, wherein: Along the first direction, the distance between the first electrode tab and the first main body is W1, the length of the first sealing area is D1, and 2mm≤D1≤0.4W1.

3. The secondary battery according to claim 1, wherein: The first extension portion is spaced apart from the electrode assembly.

4. The secondary battery according to claim 1, wherein: The first extension portion does not extend beyond the first main body portion.

5. The secondary battery according to claim 1, wherein: The second pole tab includes a second extension portion, which at least partially overlaps the top seal portion along a thickness direction of the top seal portion, and is connected to a side of the first body portion away from the first pole tab along the first direction.

6. The secondary battery according to claim 5, characterized in that: The top seal portion includes a first side edge, and along the first direction, the first side edge is located on a side of the second pole ear away from the first pole ear, the distance between the first side edge and the first main body portion is W2, and the distance between the second extension portion and the first side edge is W3, 2mm≤W3≤0.4W2.

7. The secondary battery according to claim 5, characterized in that: Both ends of the first extension portion extend out of the top sealing portion, and / or both ends of the second extension portion extend out of the top sealing portion.

8. The secondary battery according to claim 7, characterized in that Along the extending direction of the top sealing portion, the width of the top sealing portion is H1, the width of the first extending portion is H2, H1≤H2≤2H1, and / or the width of the second extending portion is H3, H1≤H3≤2H1.

9. The secondary battery according to claim 1 or 5, characterized in that: The first electrode tab includes a second main body portion and a third extension portion, one end of the second main body portion is connected to the electrode assembly, the other end of the second main body portion extends out of the packaging bag from the top seal portion, along the thickness direction of the top seal portion, the third extension portion at least partially overlaps with the top seal portion, along the first direction, the third extension portion is connected to a side of the second main body portion close to the second electrode tab, the third extension portion is spaced apart from the first extension portion, and the first sealing area is located between the third extension portion and the first extension portion.

10. The secondary battery according to claim 1 or 5, characterized in that: The first electrode tab includes a second main body portion and a fourth extension portion, one end of the second main body portion is connected to the electrode assembly, the other end of the second main body portion extends out of the packaging bag from the top seal portion, along the thickness direction of the top seal portion, the fourth extension portion at least partially overlaps with the top seal portion, along the first direction, the fourth extension portion is connected to a side of the second main body portion away from the second electrode tab, the second main body portion and the first extension portion are spaced apart, and the first sealing area is located between the second main body portion and the first extension portion.

11. The secondary battery according to claim 10, characterized in that: The top seal portion includes a second side edge, and along the first direction, the second side edge is located on a side of the first pole ear away from the second pole ear, the distance between the second side edge and the second body portion is W4, and the distance between the fourth extension portion and the second side edge is W5, 2mm≤W5≤0.4W4.

12. The secondary battery according to claim 9, wherein: The first pole tab includes a fourth extension portion, which at least partially overlaps with the top seal portion along a thickness direction of the top seal portion, and is connected to a side of the second body portion away from the second pole tab along the first direction.

13. The secondary battery according to claim 12, characterized in that: Both ends of the third extending portion extend out of the top sealing portion, and / or both ends of the fourth extending portion extend out of the top sealing portion.

14. The secondary battery according to claim 13, characterized in that: Along the extending direction of the top sealing portion, the width of the top sealing portion is H1, the width of the third extending portion is H4, H1≤H4≤2H1, and / or the width of the fourth extending portion is H5, H1≤H5≤2H1.

15. The secondary battery according to claim 1, wherein: The secondary battery comprises: A first electrode ear glue, wherein the first electrode ear glue at least wraps the surface of a portion of the first electrode ear located in the top seal portion; and / or The second electrode tab glue at least wraps the surface of the portion of the second electrode tab located in the top seal portion.

16. The secondary battery according to claim 1, wherein: The first electrode tab is a negative electrode tab, and the second electrode tab is a positive electrode tab.

17. An electronic device, characterized in that: The electronic device includes the secondary battery according to any one of claims 1 to 16.

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