Secondary battery and electronic apparatus

Abstract

A secondary battery and an electronic apparatus. The secondary battery comprises: a packaging bag, an electrode assembly, and a first tab. The packaging bag comprises a main body part and a first sealing part. The electrode assembly is accommodated in the main body part. The main body part comprises a first end wall, a second end wall, and a first side wall. The first sealing part is connected to the first side wall. The electrode assembly comprises an electrode assembly body and a plurality of first polar members extending from the electrode assembly body. The plurality of first polar members comprise at least two first sub-polar members and at least two second sub-polar members. The at least two first sub-polar members are folded in the direction of the first end wall and stacked to form a first current collection part. The at least two second sub-polar members are folded in the direction of the second end wall and stacked to form a second current collection part. The second current collection part and the first current collection part are both electrically connected to the first tab. By means of the above solution, wasted space in the height direction of the secondary battery can be reduced, which is beneficial to the improvement of the battery capacity.

Description

Secondary battery and electronic device

[0001] This application claims priority to the prior application with application number 202410172302.0 filed with the State Intellectual Property Office of China on February 6, 2024, entitled “Secondary Batteries and Electronic Devices”. The contents of the above-mentioned prior application are incorporated into this text by introduction. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to a secondary battery and an electronic device. Background Art

[0003] The head of a secondary battery occupies a large space, resulting in wasted space in its height direction. In the soft-pack secondary battery shown in Figure 1, the packaging bag has a sealing portion extending outward from the top surface of the main body. To reduce the possibility of contact between the metal strip and the exposed metal layer of the sealing portion, the tab glue on the tab will extend beyond the sealing portion by a certain distance. The distance S where the tab glue extends beyond the sealing portion directly affects the amount of space occupied by the side of the tab. That is, the greater the distance where the tab glue extends beyond the sealing portion, the more space occupied by the side of the tab in the height direction.

[0004] The inventors of this application have discovered through research that the spacing between the tab glue and the portion of the tab that extends beyond the top seal is related to the multiple polar components of the same polarity on the electrode assembly. This is because the metal strip is typically secured to the multiple polar components on the electrode assembly. Once the tab and electrode assembly are assembled into a housing, the multiple polar components of the same polarity all bend in the same direction, creating an uncontrolled bending rebound force. This causes the actual installation position of the tab glue to deviate significantly from the intended installation position in the height direction. After curing, the tab glue is very hard and difficult to bend. Even after bending, there are many interference areas on the tab glue, resulting in wasted space in the height direction on the side where the tab is located.

[0005] Application Contents

[0006] The purpose of this application is to provide a secondary battery and an electrical device to facilitate the subsequent disassembly and replacement of the secondary battery.

[0007] The purpose of this application is to provide a secondary battery and an electronic device, aiming to reduce space waste in the height direction to facilitate the improvement of battery capacity.

[0008] In a first aspect, the present application provides a secondary battery comprising: a packaging bag, an electrode assembly, and a first tab. The packaging bag comprises a main body and a first sealing portion. The electrode assembly is housed within the main body. The main body comprises a first end wall, a second end wall, and a first side wall. The first end wall and the second end wall are disposed opposite each other along a first direction, the first side wall is connected between the first and second end walls, and the first sealing portion is connected to the first side wall. The first tab comprises a first metal strip and a first tab adhesive wrapped around the first metal strip. The first metal strip is secured to the first sealing portion by the first tab adhesive. The electrode assembly comprises an electrode assembly body and a plurality of first polar members extending from the electrode assembly body. The plurality of first polar members comprise at least two first sub-polar members and at least two second sub-polar members. The at least two first sub-polar members converge toward the first end wall and overlap to form a first current collecting portion. The at least two second sub-polar members converge toward the second end wall and overlap to form a second current collecting portion. The second current collecting portion and the first current collecting portion are both electrically connected to the first metal strip.

[0009] The secondary battery involved in the present application is that since the total number of first sub-polar parts or the total number of second sub-polar parts is reduced compared with the total number of first polar parts bent in the same direction alone, the sum of the bending rebound forces generated after at least two first sub-polar parts are bent or the sum of the bending rebound forces generated after at least two second sub-polar parts are bent is also reduced, so that the first metal strip connected to the first sub-polar parts and the second sub-polar parts is less affected by the two, that is, the actual installation position of the first pole ear glue deviates less from the predetermined installation position of the first pole ear glue in the height direction (the direction opposite to the third direction), thereby reducing the waste of space in the height direction on the side where the first pole ear is located, which is beneficial to improving the capacity of the secondary battery.

[0010] In one or more of the above optional embodiments, a gap is formed between the first sidewall and the electrode assembly body. The secondary battery includes a first adapter positioned within the gap. The first metal strip is electrically connected to the first and second current collecting portions via the first adapter.

[0011] In one or more of the above optional embodiments, the first adapter extends along the second direction. When viewed along the third direction, the projection of the first current collecting portion and the projection of the second current collecting portion are both spaced apart from the projection of the first metal strip. The third direction, the second direction, and the first direction are all perpendicular to each other.

[0012] In one or more of the above optional embodiments, the first current collecting portion comprises at least two first conductive segments, a first curved segment, and a first connecting segment. The at least two first conductive segments extend from the electrode assembly body, the at least two first conductive segments converge toward the first end wall, one end of the first connecting segment is connected to the at least two first conductive segments via the first curved segment, and the other end of the first connecting segment extends toward the second end wall. The first connecting segment is connected to the at least two first conductive segments via the first curved segment. The second current collecting portion comprises at least two second conductive segments, a second curved segment, and a second connecting segment. The at least two second conductive segments extend from the electrode assembly body, the at least two second conductive segments converge toward the second end wall, one end of the second connecting segment is connected to the at least two second conductive segments via the second curved segment, and the other end of the second connecting segment extends toward the first end wall. The bending direction of the second curved segment is opposite to that of the first curved segment. The first metal strip is electrically connected to the first connecting segment and the second connecting segment via the first adapter.

[0013] In one or more of the above optional embodiments, the at least two first conductive segments, the first curved segment, the first connecting segment, the at least two second conductive segments, the second curved segment, and the second connecting segment collectively enclose a first installation space. The first adapter is partially housed within the first installation space and electrically connected to the first connecting segment and the second connecting segment. The portion of the first adapter not housed within the first installation space is electrically connected to the first metal strip.

[0014] In one or more of the above optional embodiments, the second connecting segment is overlapped on the surface of the first adapter facing away from the main body, and the first connecting segment is at least partially overlapped on the second connecting segment.

[0015] In one or more optional embodiments above, the second connecting segment and the first connecting segment are both superimposed on the surface of the first adapter facing away from the main body; and when viewed along the third direction, the projection of the second connecting segment is separated from the projection of the first connecting segment.

[0016] In one or more optional embodiments above, the ratio of the number of the first sub-polarity elements to the number of the second sub-polarity elements satisfies 1:1 to 1:5, or the ratio of the number of the first sub-polarity elements to the number of the second sub-polarity elements satisfies 1:1 to 5:1.

[0017] In one or more optional embodiments above, the secondary battery includes a second pole tab. The second pole tab includes a second metal strip and a second pole tab glue arranged around the second metal strip. The second metal strip is fixed to the first sealing portion by the second pole tab glue. The electrode assembly also includes a plurality of second polarity members extending from the electrode assembly body. The plurality of second polarity members include at least two third sub-polarity members and at least two fourth sub-polarity members. The at least two third sub-polarity members are gathered toward the first end wall and stacked to form a third current collecting portion. The at least two fourth sub-polarity members are gathered toward the second end wall and stacked to form a fourth current collecting portion. The fourth current collecting portion and the third current collecting portion are both electrically connected to the second metal strip.

[0018] In one or more optional embodiments above, the secondary battery includes a second adapter, which is located in the gap. The second metal strip is electrically connected to the third collector and the fourth collector via the adapter.

[0019] In one or more of the above optional embodiments, the second adapter extends in a direction opposite to the second direction. When viewed along a third direction, the projection of the third current collecting portion and the projection of the fourth current collecting portion are both spaced apart from the projection of the second metal strip. The third direction, the second direction, and the first direction are all perpendicular to each other.

[0020] In one or more optional embodiments above, the third current collecting portion includes at least two third conductive segments, a third curved segment, and a third connecting segment. The at least two third conductive segments extend from the electrode assembly body, the at least two third conductive segments converge toward the first end wall and overlap along the third direction, and the third connecting segment is connected to the at least two third conductive segments via the third curved segment. The fourth current collecting portion includes at least two fourth conductive segments, a fourth curved segment, and a fourth connecting segment. The at least two fourth conductive segments extend from the electrode assembly body, the at least two fourth conductive segments converge toward the second end wall and overlap along the third direction, and the fourth connecting segment is connected to the at least two fourth conductive segments via the fourth curved segment. The bending direction of the fourth curved segment is opposite to that of the third curved segment. The second metal strip is electrically connected to the third connecting segment and the fourth connecting segment via the second adapter.

[0021] In one or more of the above optional embodiments, the at least two third conductive segments, the third curved segment, the third connecting segment, the at least two fourth conductive segments, the fourth curved segment, and the fourth connecting segment collectively enclose a second installation space. The second adapter is partially housed within the second installation space and electrically connected to the third connecting segment and the fourth connecting segment. The portion of the second adapter not housed within the second installation space is electrically connected to the second metal strip.

[0022] In one or more optional embodiments above, the fourth connecting segment is overlapped on the surface of the second adapter facing away from the main body, and part of the third connecting segment is overlapped on the fourth connecting segment.

[0023] In one or more optional embodiments above, the ratio of the number of the third sub-polarity elements to the number of the fourth sub-polarity elements satisfies 1:1 to 1:5. Alternatively, the ratio of the number of the third sub-polarity elements to the number of the fourth sub-polarity elements satisfies 1:1 to 5:1.

[0024] In one or more of the above optional embodiments, the first adapter includes a first conductive layer and a first insulating layer. The first insulating layer is formed on a surface of the first conductive layer facing the first sidewall. The first metal strip is electrically connected to the first collector portion and the second collector portion via the first conductive layer.

[0025] In one or more of the above optional embodiments, the second transition member includes a second conductive layer and a second insulating layer. The second insulating layer is formed on a surface of the second conductive layer facing the first sidewall. The second metal strip is electrically connected to the third and fourth current collecting portions via the second conductive layer.

[0026] In one or more optional embodiments above, the second insulating layer is integrally connected to the first insulating layer, and the second conductive layer is not in contact with the first conductive layer.

[0027] In one or more optional embodiments above, the first metal strip is fixed to the first conductive layer by welding.

[0028] In one or more optional embodiments above, the first current collecting portion is fixed to the first conductive layer by welding.

[0029] In one or more optional embodiments above, the second current collecting portion is fixed to the first conductive layer by welding.

[0030] In one or more optional embodiments above, the first insulating layer is made of a first adhesive insulating material, and the first insulating layer is adhesively fixed to the first collecting portion and the second collecting portion.

[0031] In one or more optional embodiments above, along the third direction, the thickness of the first insulating layer is T2, 0.01 mm ≤ T2 ≤ 0.2 mm.

[0032] In one or more of the above optional embodiments, the first conductive layer is made of metal material.

[0033] In one or more optional embodiments above, along the third direction, the thickness of the first conductive layer is T3, 0.01 mm ≤ T3 ≤ 2 mm.

[0034] In one or more optional embodiments above, the second metal strip is fixed to the second conductive layer by welding.

[0035] In one or more optional embodiments above, the third current collecting portion is fixed to the second conductive layer by welding.

[0036] In one or more optional embodiments above, the fourth current collecting portion is fixed to the second conductive layer by welding.

[0037] In one or more optional embodiments above, the second insulating layer is made of a second adhesive insulating material, and the second insulating layer is adhesively fixed to the third collecting part and the fourth collecting part.

[0038] In one or more optional embodiments above, along the third direction, the thickness of the second insulating layer is T4, 0.01 mm ≤ T4 ≤ 0.2 mm.

[0039] In one or more optional embodiments above, the second conductive layer is made of metal material.

[0040] In one or more optional embodiments above, along the third direction, the thickness of the second conductive layer is T5, 0.01 mm ≤ T5 ≤ 2 mm.

[0041] In one or more optional embodiments above, the first viscous insulating material and the second viscous insulating material independently include at least one of polypropylene, polyethylene, butyl rubber, acrylic glue, modified polyolefin, copolymer of styrene and butadiene, and acrylic glue.

[0042] In one or more optional embodiments above, the first metal material and the second metal material each independently include one of aluminum, copper, nickel, titanium, copper-nickel alloy, aluminum-copper alloy, and stainless steel.

[0043] In one or more optional embodiments above, in a direction opposite to the third direction, the first tab glue extends beyond the first sealing portion by a length of 0 mm to 1.7 mm. Furthermore, in a direction opposite to the third direction, the second tab glue extends beyond the first sealing portion by a length of 0 mm to 1.7 mm.

[0044] According to a second aspect of the present application, an electronic device is provided, comprising the secondary battery described above.

[0045] Additional aspects and advantages of the embodiments of the present application will be described, shown, or explained in part in the following description through implementation of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] To more clearly illustrate the specific embodiments of this application or the technical solutions in the prior art, the following briefly describes the drawings required for the specific embodiments or the description of the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. Elements or parts in the drawings are not necessarily drawn to scale.

[0047] FIG1 is a schematic structural diagram of a soft-pack secondary battery shown in the related art;

[0048] FIG2 is a schematic structural diagram of a secondary battery provided in one embodiment of the present application;

[0049] FIG3 is a schematic diagram of the secondary battery assembly structure shown in FIG2 ;

[0050] FIG4 is a schematic diagram of another assembly structure of the secondary battery shown in FIG2 ;

[0051] FIG5 is an exploded view of the structure of the secondary battery shown in FIG2 ;

[0052] FIG6 is a schematic structural diagram of the secondary battery shown in FIG5 without the packaging bag;

[0053] FIG7 is a partial enlarged view obtained by cutting along line AA in FIG6;

[0054] FIG8 is a partial enlarged view obtained by cutting along line BB in FIG6;

[0055] FIG9 is a partial enlarged view obtained by cutting along line CC in FIG6 ;

[0056] FIG10 is a partial enlarged view obtained by cutting along line DD in FIG6;

[0057] FIG11 is a schematic structural diagram of the first adapter and the second adapter in the secondary battery shown in FIG5 ;

[0058] FIG12 is an exploded view of the structure of another secondary battery provided by one embodiment of the present application;

[0059] FIG13 is a schematic structural diagram of the secondary battery shown in FIG12 without the packaging bag;

[0060] FIG14 is a schematic structural diagram of the first adapter and the second adapter in the secondary battery shown in FIG12 ;

[0061] FIG15 is a schematic structural diagram of another secondary battery provided in one embodiment of the present application.

[0062] 10. Packaging bag; 101. Main body; 102. First sealing portion; 103. Second sealing portion; 104. Third sealing portion; 11. First sheet; 111. First end wall; 112. First side wall; 113. Second side wall; 114. Third side wall; 115. Fourth side wall; 116. First connecting wall; 117. Second connecting wall; 118. Third connecting wall; 12. Second sheet; 121. Second end wall; 122. Fourth connecting wall; 123. Fifth connecting wall; 124. Sixth connecting wall;

[0063] 20. Electrode assembly; 211. First polar member; 221. Second polar member; 201. Electrode assembly body; 202. First current collecting portion; 2021. First conductive segment; 2022. First curved segment; 2023. First connecting segment; 203. Second current collecting portion; 2031. Second conductive segment; 2032. Second curved segment; 2033. Second connecting segment; 204. Third current collecting portion; 2041. Third conductive segment; 2042. Third curved segment; 2043. Third connecting segment; 205. Fourth current collecting portion; 2051. Fourth conductive segment; 2052. Fourth curved segment; 2053. Fourth connecting segment;

[0064] 30. First tab; 31. First metal strip; 311. First portion; 312. Second portion; 32. First tab glue;

[0065] 40. Second tab; 41. First metal strip; 411. Third portion; 412. Fourth portion; 42. Second tab glue;

[0066] 50. First adapter; 51. First conductive layer; 52. First insulating layer;

[0067] 60. Second adapter; 61. Second conductive layer; 62. Second insulating layer;

[0068] X, first direction; Y, second direction; Z, third direction. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0070] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0071] In the description of this application, it should be noted that, unless otherwise specified or limited, the terms "mounted" and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0072] The term "perpendicular" is used to describe the ideal state between two components. In actual production or use, there may be a state that is approximately perpendicular between the two components. For example, combined with numerical descriptions, perpendicular can refer to the angle between two straight lines being in the range of 90°±10°, perpendicular can also refer to the dihedral angle between two planes being in the range of 90°±10°, and perpendicular can also refer to the angle between a straight line and a plane being in the range of 90°±10°. The two components described as "perpendicular" may not be absolute straight lines or planes, but may be roughly straight lines or planes. From a macroscopic perspective, a component can be considered a "straight line" or a "plane" if the overall extension direction is a straight line or a plane.

[0073] The term "parallel" is used to describe the ideal state between two components. In actual production or use, there may be a state of approximate parallelism between the two components. For example, combined with numerical descriptions, parallel can refer to the angle between two straight lines being in the range of 180°±10°, parallel can also refer to the dihedral angle between two planes being in the range of 180°±10°, and parallel can also refer to the angle between a straight line and a plane being in the range of 180°±10°. The two components described as "parallel" may not be absolute straight lines or planes, but may be roughly straight lines or planes. From a macroscopic perspective, a component can be considered a "straight line" or a "plane" if its overall extension direction is a straight line or a plane.

[0074] The technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0075] As shown in Figures 2-15, the secondary battery includes a packaging bag 10, an electrode assembly 20, a first electrode tab 30, and a second electrode tab 40. The packaging bag 10 serves as a protective structure for the electrode assembly 20 and defines a housing cavity (not shown) within which the electrode assembly 20 is housed. The first electrode tab 30 and the second electrode tab 40 are both fixed to the packaging bag 10. The end of the first electrode tab 30 extending into the housing cavity is electrically connected to one electrode of the electrode assembly 20, and the end of the second electrode tab 40 extending into the housing cavity is electrically connected to the other electrode of the electrode assembly 20. The end of the first electrode tab 30 and the end of the second electrode tab 40 extending outside the packaging bag 10 are configured to be electrically connected to an electronic device to achieve the conversion between chemical energy and electrical energy of the secondary battery. It should be noted that the electronic device mentioned here does not only refer to electronic devices that maintain stable operation by consuming the electrical energy of the secondary battery, but also refers to electronic devices that replenish the electrical energy of the secondary battery. As such electronic devices are numerous, they will not be described in detail here.

[0076] In some embodiments, the secondary battery includes an electrolyte (not shown), the electrolyte is contained in the receiving cavity, and the electrode assembly 20 is immersed in the electrolyte.

[0077] In some embodiments, the secondary battery is a soft-pack lithium-ion secondary battery.

[0078] Next, the specific structure of a soft-pack lithium-ion secondary battery will be described using a soft-pack lithium-ion secondary battery as an example. It is understood that the secondary battery may also be other types of soft-pack lithium-ion secondary batteries in addition to soft-pack lithium-ion secondary batteries. Examples of such soft-pack secondary batteries include soft-pack sodium-ion secondary batteries, solid-state soft-pack secondary batteries, and semi-solid-state soft-pack secondary batteries.

[0079] Regarding the packaging bag 10, in some embodiments, it includes a main body 101 and a first sealing portion 102. The main body 101 includes a first end wall 111, a second end wall 121, and a peripheral wall. The first end wall 111 and the second end wall 121 are arranged opposite to each other, and the peripheral wall is located between the first end wall 111 and the second end wall 121, and is connected to the first end wall 111 and the second end wall 121 on all sides. The first end wall 111, the second end wall 121, and the peripheral wall are together arranged to form the aforementioned accommodating cavity. The peripheral wall includes a first side wall 112 located on one side of the main body 101, the first sealing portion 102 is connected to the first side wall 112 and extends out of the accommodating cavity, and the first tab 30 is fixed to the first sealing portion 102.

[0080] Next, the specific structure of the packaging bag 10 will be described in conjunction with Figures 2 to 5, Figure 12, or Figure 15. As shown in Figures 2 and 3, in some embodiments, the packaging bag 10 is generally flat and rectangular, and includes a first sheet 11 and a second sheet 12. The first sheet 11 and the second sheet 12 are sealed and connected to form the aforementioned receiving cavity.

[0081] The first body 11 includes a first end wall 111 and a peripheral wall. The peripheral wall includes a first side wall 112, a second side wall 113, a third side wall 114, and a fourth side wall 115. The first side wall 112, the second side wall 113, the third side wall 114, and the fourth side wall 115 are sequentially connected end to end and are integrally connected to the four sides of the first end wall 111. The first side wall 112, the second side wall 113, the third side wall 114, the fourth side wall 115, and the first end wall 111 collectively enclose a receiving cavity with an open opening.

[0082] In addition, the first plate 11 further includes a first connecting wall 116, a second connecting wall 117, and a third connecting wall 118. The first connecting wall 116 is integrally connected to an end of the first side wall 112 away from the first end wall 111 and extends away from the first side wall 112. The second connecting wall 117 is integrally connected to an end of the second side wall 113 away from the first end wall 111 and extends away from the first side wall 112. The third connecting wall 118 is integrally connected to an end of the fourth side wall 115 away from the first end wall 111 and extends away from the fourth side wall 115. The first connecting wall 116 is integrally connected at its ends to the second connecting wall 117 and the fourth connecting wall 122, respectively.

[0083] Continuing with FIG3 , the shape of the second sheet 12 matches that of the first sheet 11. It includes a second end wall 121, a fourth connecting wall 122, a fifth connecting wall 123, and a sixth connecting wall 124. The fifth connecting wall 123 and the sixth connecting wall 124 are integrally connected to opposite ends of the second end wall 121. The fourth connecting wall 122 is located between the fifth connecting wall 123 and the sixth connecting wall 124 and is integrally connected to the fifth connecting wall 123, the sixth connecting wall 124, and the second end wall 121, respectively.

[0084] In a specific implementation, the same multilayer sheet is separated along the dotted line into a first sheet 11 and a second sheet 12. The first sheet 11 is stamped to form a receiving cavity with an opening, and the second sheet 12 is folded along the dotted line to completely cover the opening. The fourth connecting wall 122 and the first connecting wall 116, the fifth connecting wall 123 and the second connecting wall 117, and the sixth connecting wall 124 and the third connecting wall 118 are then directly heat-pressed. Thus, the first connecting wall 116 and the fourth connecting wall 122 are bonded together to form the aforementioned first sealing portion 102; the second connecting wall 117 and the fifth connecting wall 123 are bonded together to form the second sealing portion 103; the third connecting wall 118 and the sixth connecting wall 124 are bonded together to form the third sealing portion 104; and the first end wall 111, the second end wall 121, the first side wall 112, the second side wall 113, the third side wall 114, and the fourth side wall 115 collectively constitute the aforementioned main body 101. The first end wall 111 and the second end wall 121 are arranged opposite to each other along a first direction X, and the second side wall 113 and the fourth side wall 115 are arranged opposite to each other along a second direction Y. The first side wall 112 and the third side wall 114 are arranged opposite to each other along a direction opposite to the third direction Z. For ease of understanding, the first direction X shown in Figures 2 to 15 is defined as the thickness direction of the secondary battery, the second direction Y shown is defined as the width direction of the secondary battery, and the third direction Z shown is defined as the height direction of the secondary battery. Any two of the first direction X, the second direction Y, and the third direction Z are perpendicular to each other.

[0085] Regarding the specific structure of the multilayer sheet, the embodiments of the present application do not make specific restrictions, and it is sufficient that it can block the gas-liquid exchange between the accommodating cavity and the external environment. For example, in some embodiments, the multilayer sheet is formed by stacking a first insulating material layer, a metal material layer, and a second insulating material layer in sequence. Among them, the materials used to make such a first insulating material layer and / or second insulating material layer can be listed as polyethylene, polypropylene, polycarbonate, polyamide, polyethylene terephthalate, acrylonitrile-butadiene-styrene copolymer, polyoxymethylene, polyphenylene ether, etc.; the materials used to make such a metal material layer can be listed as aluminum foil, austenitic-ferritic duplex stainless steel foil, etc. For example, the multilayer sheet is formed by stacking polyethylene terephthalate (first insulating material layer), aluminum foil (metal material layer), and polyethylene (second insulating material layer) in sequence, that is, the multilayer sheet is an aluminum-plastic film.

[0086] Of course, the first sheet 11 and the second sheet 12 are not limited to being formed by the same multi-layer sheet separated by a dotted line. For example, as shown in FIG4 , in other embodiments, the first sheet 11 and the second sheet 12 are each independent multi-layer sheets, and the specific structure of the multi-layer sheet in the first sheet 11 is the same as or different from the specific structure of the multi-layer sheet in the second sheet 12. As an example, the first sheet 11 and the second sheet 12 are both aluminum-plastic films of the same structure, or one of the first sheet 11 and the second sheet 12 is an aluminum-plastic film and the other is a steel-plastic film. The first sheet 11 and the second sheet 12 can also be directly hot-pressed or bonded together using hot melt adhesive. In this case, a sealing portion is formed on each side of the main body 101.

[0087] 2 , to enhance the structural strength of the secondary battery, in some embodiments, the second sealing portion 103 may be folded. For example, the second sealing portion 103 is double-folded and then bonded to a second sidewall 113 opposite the second sealing portion 103 .

[0088] Similarly, the third sealing portion 104 may also be folded. For example, the third sealing portion 104 is double-folded and then fixed to the fourth side wall 115 opposite to the third sealing portion 104.

[0089] It is understood that the specific form of the packaging bag 10 is not limited to that shown in Figures 2 to 5, 12, or 15. The specific shape of the main body 101 depends on the specific shape of the electrode assembly 20, which will be described in detail below. Each sealing portion can be adaptively folded according to actual usage requirements and is not limited to the double-folded edge treatment of the second sealing portion 103 or the third sealing portion 104 described above.

[0090] Regarding the first tab 30, please refer to Figure 2 in conjunction with Figure 8 and Figure 3. In some embodiments, the first tab 30 includes a first metal strip 31 and a first tab adhesive 32 surrounding and wrapping around the first metal strip 31. The first metal strip 31 includes a first portion 311 and a second portion 312. The first tab adhesive 32 surrounds the first portion 311, with a portion of the first tab adhesive 32 extending beyond the first sealing portion 102 in the third direction Z. The first tab adhesive 32 is sandwiched between the first connecting wall 116 and the fourth connecting wall 122 to seal the gap between the first metal strip 31 and the first sealing portion 102. One end of the first portion 311, along the third direction Z, extends into the housing and connects to the second portion 312. The other end of the first portion 311, along the third direction Z, extends outside the housing and is configured to electrically connect to an electronic device. The second portion 312 is located within the housing and electrically connected to one electrode of the electrode assembly 20, forming an angle between the second portion 312 and the first portion 311. Here, by bending the first metal strip 31, the contact area between the first metal strip 31 and one pole of the electrode assembly 20 is increased, which can improve the current carrying capacity of the first electrode tab 30 and the electrode assembly 20 on the one hand, and improve the stability of the connection between the two on the other hand.

[0091] Of course, the specific structure of the first metal strip 31 is not limited to the sheet metal foil shown in FIG5 , and can be adaptively adjusted according to actual usage requirements. For example, in other embodiments, the first metal strip 31 is an unbent strip of metal foil, or the first metal strip 31 is an elongated strip structure.

[0092] In some embodiments, the first metal strip 31 includes, but is not limited to, one or more conductive metal sheets such as aluminum mesh, aluminum foil, copper foil, etc. As an example, the first metal strip 31 is made of aluminum foil.

[0093] Regarding the second tab 40, please refer to Figure 2 in conjunction with Figures 9 and 3. In some embodiments, the second tab 40 includes a second metal strip 41 and a second tab adhesive 42 wrapped around the second metal strip 41. The second metal strip 41 includes a third portion 411 and a fourth portion 412. The second tab adhesive 42 wraps around the third portion 411 and is sandwiched between the first connecting wall 116 and the fourth connecting wall 122. A portion of the second tab adhesive 42 extends beyond the first sealing portion 102 in the third direction Z. One end of the third portion 411 along the third direction Z extends into the accommodating cavity and connects to the fourth portion 412. The other end of the third portion 411 along the third direction Z extends outside the housing and is configured to be electrically connected to an electronic device. The fourth portion 412 is located within the accommodating cavity and is electrically connected to the other pole of the electrode assembly 20. The fourth portion 412 forms an angle with the third portion 411. Here, by bending the second metal strip 41, the contact area between the second metal strip 41 and the other pole of the electrode assembly 20 is increased, which can improve the current carrying capacity of the second electrode tab 40 and the electrode assembly 20 on the one hand, and improve the stability of the connection between the two on the other hand.

[0094] Of course, the specific structure of the second metal strip 41 is not limited to the sheet metal foil shown in FIG5 , and can be adaptively adjusted according to actual usage requirements. For example, in other embodiments, the second metal strip 41 is an unbent strip of metal foil, or the second metal strip 41 is an elongated strip structure.

[0095] In some embodiments, the second metal strip 41 includes, but is not limited to, one or two of conductive metal sheets such as nickel foil and copper foil. As an example, the second metal strip 41 is made of nickel foil.

[0096] For the electrode assembly 20, in some embodiments, the electrode assembly 20 includes multiple first pole pieces (not shown), multiple isolation membranes (not shown), and multiple second pole pieces (not shown) having different polarity from the first pole pieces. The multiple first pole pieces and the multiple second pole pieces are alternately stacked, and the first pole pieces and their adjacent second pole pieces are separated by isolation membranes to form a stacked structure.

[0097] Of course, the electrode assembly 20 may also be any type of electrode assembly 20 other than this stacked structure, as long as it can achieve the charge and discharge functions of the secondary battery. For example, in other embodiments, the electrode assembly 20 may include a first electrode sheet, a separator, and a second electrode sheet, which are stacked and wound in sequence to form a wound structure.

[0098] One of the first electrode and the second electrode can be a positive electrode, and the other of the first electrode and the second electrode can be a negative electrode. For ease of description, the following embodiments are all described as an example in which the first electrode is a positive electrode and the second electrode is a negative electrode.

[0099] In some embodiments, the first electrode sheet includes a first electrode sheet body (not shown) and a plurality of first polar members 211 spaced apart from the first electrode sheet body. The first electrode sheet body includes a first current collector (not shown) and a first active material layer (not shown). The first active material layer is coated on at least one surface of the first current collector. The plurality of first polar members 211 are each connected to the first current collector and extend outward from one side of the first current collector body. The plurality of first polar members 211 serve as one pole of the electrode assembly 20 and are electrically connected to the first metal strip 31.

[0100] It is understood that the various embodiments of the present application do not specifically limit the connection method between the first polar member 211 and the first current collector. For example, in some embodiments, the first polar member 211 is integrally connected to the first current collector. During implementation, the first polar member 211 and the first current collector can be die-cut from a complete metal foil. For another example, in other embodiments, the first polar member 211 is welded to the first current collector. During implementation, a portion of the first active material layer can be scraped off from the first current collector coated with the first active material layer, and then a single first polar member 211 can be fixed to the surface of the exposed first current collector by, but not limited to, laser welding.

[0101] In some embodiments, the first polar element 211 and / or the first current collector include, but are not limited to, one or more conductive metal sheets such as aluminum mesh, aluminum foil, and copper foil.

[0102] In some embodiments, the first active material layer may include, but is not limited to, one or more of lithium cobaltate, lithium nickel cobalt manganeseate, lithium nickel cobalt aluminumate, lithium manganeseate, lithium nickelate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium iron phosphate, and lithium-rich manganese-based materials.

[0103] In some embodiments, the second electrode sheet includes a second electrode sheet body (not shown) and a plurality of second polar members 221 spaced apart from the second electrode sheet body. The second electrode sheet body includes a second current collector (not shown) and a second active material layer (not shown). The second active material layer is coated on at least one surface of the second current collector. The second polar members 221 are each connected to the second current collector, and the plurality of second polar members 221 extend outward from one side of the second current collector. The plurality of second polar members 221 serve as the other pole of the electrode assembly 20 and are electrically connected to the second electrode tab 40 of the secondary battery.

[0104] It is understood that the various embodiments of the present application do not specifically limit the connection method between the second polar member 221 and the second current collector. Since the connection method between the second polar member 221 and the second current collector is similar to the connection method between the first polar member 211 and the first current collector, please refer to the connection method between the first polar member 211 and the first current collector described above and will not be further described here.

[0105] In some embodiments, the second polar member 221 and / or the second current collector may include, but is not limited to, one or both of conductive metal sheets such as nickel foil and copper foil.

[0106] In some embodiments, the second active material layer may include, but is not limited to, one or more of artificial graphite, natural graphite, soft carbon, hard carbon, graphene, mesocarbon microbeads, silicon-based materials, tin-based materials, lithium carbonate, or other metals that can form alloys with lithium.

[0107] Next, the specific structure of the electrode assembly 20 will be described in conjunction with the examples shown in Figures 5 to 10. As shown in Figure 5, in some embodiments, the electrode assembly 20 is generally flat and rectangular, and includes an electrode assembly body 201, multiple first polarity members 211, and multiple second polarity members 221. The electrode assembly body 201 is housed within the accommodating cavity, with a gap formed between the electrode assembly body 201 and the first sidewall 112. The electrode assembly body 201 is formed by alternatingly stacking multiple first pole piece bodies, multiple separators, and multiple second pole piece bodies. The multiple first polarity members 211 and the multiple second polarity members 221 extend from the same side of the electrode assembly body 201 into the gap, and are spaced apart along the second direction Y. The multiple first polarity members 211 are electrically connected to the first metal strip 31, and the multiple second polarity members 221 are electrically connected to the second metal strip 41.

[0108] It is understood that the plurality of first polarity members 211 and the plurality of second polarity members 221 can be adaptively adjusted according to actual usage requirements. For example, as shown in FIG15 , in other embodiments, the plurality of first polarity members 211 still extend from the first sealing portion 102 , while the plurality of second polarity members 221 can extend from a sealing portion opposite the first sealing portion.

[0109] In the above technical solution, multiple first polar members 211 and multiple second polar members 221 all extend from the same side of the electrode assembly body 201. Corresponding to the extending directions of the multiple first polar members 211 and the multiple second polar members 221, the first pole tab 30 and the second pole tab 40 also extend from the first sealing portion 102. Compared with the first pole tab 30 and the second pole tab 40 extending from the sealing portions on different sides respectively, the manufacturing process and assembly process of the secondary battery can be simplified, thereby reducing the production cost of the secondary battery.

[0110] Referring also to the example shown in FIG7 , in some embodiments, the plurality of first polarity members 211 include at least two first sub-polarity members (not shown) and at least two second sub-polarity members (not shown). The at least two first sub-polarity members converge toward the first end wall 111 and overlap to form a first current collecting portion 202 , and the at least two second sub-polarity members converge toward the second end wall 121 and overlap to form a second current collecting portion 203 . The second current collecting portion 203 and the first current collecting portion 202 are both electrically connected to the second portion 312 .

[0111] Specifically, the first current collecting portion 202 has at least two first conductive segments 2021, a first curved segment 2022, and a first connecting segment 2023. The at least two first conductive segments 2021 extend from the electrode assembly body 201, converge toward the first end wall 111, and overlap in a direction opposite to the third direction Z. One end of the first connecting segment 2023 is connected to the at least two first conductive segments 2021 via the first curved segment 2022, and the other end of the first connecting segment 2023 extends toward the second end wall 121. The first connecting segment 2023 is electrically connected to the first electrode tab 30. The first conductive segment 2021 is the portion of a single first sub-polarity member that extends outside the first electrode body and overlaps with an adjacent first sub-polarity member. The first curved segment 2022 is formed by bending the interconnected portions of multiple first sub-polarity members away from the first end wall 111. The first connecting segment 2023 is formed by extending from one end of the first curved segment 2022 away from the first conductive segment 2021 toward away from the first curved segment 2022 .

[0112] The second current collecting portion 203 comprises at least two second conductive segments 2031, a second curved segment 2032, and a second connecting segment 2033. The at least two second conductive segments 2031 extend from the electrode assembly body 201. The at least two second conductive segments 2031 converge toward the second end wall 121 and overlap in a direction opposite to the third direction Z. One end of the second connecting segment 2033 is connected to the at least two second conductive segments 2031 via the second curved segment 2032. The second curved segment 2032 bends in a direction opposite to that of the first curved segment 2022. The other end of the second connecting segment 2033 extends toward the first end wall 111. The second connecting segment 2033 is electrically connected to the second portion 312. The second conductive segment 2031 is the portion of a single second sub-polarity member that extends outside the first electrode body and overlaps with an adjacent second sub-polarity member. The second curved segment 2032 is formed by bending the interconnected portions of multiple second sub-polarity members away from the second end wall 121. The second connecting segment 2033 is formed by extending from one end of the second curved segment 2032 away from the second conductive segment 2031 toward away from the second curved segment 2032 .

[0113] The secondary battery involved in the present application is that since the total number of first sub-polar parts or the total number of second sub-polar parts is reduced compared with the total number of first polar parts 211 bent in the same direction in the related art, the sum of the bending rebound forces generated after the bending of at least two first sub-polar parts or the sum of the bending rebound forces generated after the bending of at least two second sub-polar parts is also reduced, so that the first metal strip 31 connected to the first sub-polar part and the second sub-polar part is less affected by the two, that is, the actual installation position of the first pole ear glue 32 deviates less from the predetermined installation position of the first pole ear glue 32 in the height direction (the direction opposite to the third direction Z), thereby reducing the waste of space in the height direction on the side where the first pole ear 30 is located, which is beneficial to improving the capacity of the secondary battery.

[0114] In some embodiments, the ratio of the total number of first sub-polarity members to the total number of second sub-polarity members satisfies a range of 1:1 to 1:5. This is because if the ratio of the total number of first sub-polarity members to the total number of second sub-polarity members exceeds 1:5, it means that the total bending resilience generated by the bending of the plurality of first polarity members 211 decreases slightly, and the space occupied by the plurality of first polarity members 211 does not decrease significantly. Therefore, by limiting the ratio of the total number of first sub-polarity members to the total number of second sub-polarity members to within this range, the difference between the total number of first sub-polarity members and the total number of second sub-polarity members is small, and the difference between the total bending resilience generated by the bending of the plurality of first sub-polarity members and the total bending resilience generated by the bending of the plurality of second sub-polarity members is small. As a result, the gap between the electrode assembly body 201 and the first sidewall 112 is further reduced, and the volume energy density of the secondary battery can be further improved.

[0115] For example, the ratio of the total number of first sub-polarity components to the total number of second sub-polarity components is specifically within the range defined by any two of 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.5, 1:2, 1:3, 1:4, and 1:5. Furthermore, the ratio of the total number of first sub-polarity components to the total number of second sub-polarity components is 1:1.

[0116] Alternatively, the ratio of the total number of the first sub-polarity elements to the total number of the second sub-polarity elements may also satisfy 1:1 to 5:1. Based on the similar effects to those in the above embodiment, no further description is given here.

[0117] In some embodiments, the second portion 312, part of the first connecting segment 2023, and the second connecting segment 2033 are stacked in sequence, so that any two of the second portion 312, part of the first connecting segment 2023, and the second connecting segment 2033 can fully contact each other, thereby reducing the resistance at the connection between the three.

[0118] It should be noted that when the thickness of the electrode assembly body 201 in the first direction X is less than 4 mm, the end of the first connecting segment 2023 away from the first curved segment 2022 and the end of the second connecting segment 2033 away from the second curved segment 2032 need to be trimmed. After trimming, the electrical connection reliability of any two adjacent conductive segments in the overlapping area is improved. However, when the thickness of the electrode assembly body 201 in the first direction X is greater than or equal to 4 mm, the end of the first connecting segment 2023 away from the first curved segment 2022 and / or the end of the second connecting segment 2033 away from the second curved segment 2032 can be trimmed based on actual usage requirements.

[0119] Furthermore, the second portion 312, a portion of the first connecting segment 2023, and the second connecting segment 2033 are fixed together by welding. Since the second portion 312, a portion of the first connecting segment 2023, and the second connecting segment 2033 are stacked in sequence, there is no need to weld the first connecting segment 2023 and the second connecting segment 2033 to the second portion 312 separately, thereby reducing the number of welding operations and improving the production efficiency of the secondary battery.

[0120] As shown in FIG7 , in some embodiments, along the first direction X, the distance between the end of the first connecting segment 2023 away from the first curved segment 2022 and the second curved segment 2032 is D1 (in mm), and the thickness of the electrode assembly body 201 in the first direction X is T1 (in mm), and both satisfy the following relationship: 0.1 mm ≤ D1 ≤ T1. D1 is limited to this numerical range because, without affecting the volumetric energy density of the secondary battery, the first connecting segment 2023 is less affected by the bending resilience of the first curved segment 2022 and has a smaller degree of warping, thereby leaving sufficient area for contact with the second portion 312.

[0121] Continuing with FIG8 , in some embodiments, along the first direction X, the distance D2 (in mm) between the end of the second connecting segment 2033 distal from the second curved segment 2032 and the first curved segment 2022 satisfies the following relationship: 0.1 mm ≤ D2 ≤ T1 / 2. D2 is limited to this numerical range because, if D2 < 0.1 mm, the length of the second connecting segment 2033 is approximately the same as the thickness of the electrode assembly body 201 along the first direction X, potentially interfering with the first curved segment 2022, increasing assembly difficulty and occupying more space in the third direction Z. If D2 > T1 / 2, the first connecting segment 2023 is significantly affected by the bending rebound force of the first curved segment 2022, resulting in a greater degree of warpage. This increases assembly difficulty and reduces connection reliability. Therefore, when D2 is within this numerical range, the difficulty of assembling the two components can be reduced, the connection reliability can be improved, and the occupied space in the third direction Z can be reduced. For example, 0.3 mm ≤ D2 ≤ 1.5 mm.

[0122] Of course, the connection method between the second portion 312, the first connecting segment 2023, and the second connecting segment 2033 is not limited to this, as long as both are electrically conductive with the second portion 312. For example, in other embodiments, the second portion 312, a portion of the second connecting segment 2033, and the first connecting segment 2023 are sequentially stacked. For another example, in other embodiments, the first connecting segment 2023 and the second connecting segment 2033 are respectively in contact with the second portion 312, and when viewed along the third direction Z, the projection of the first connecting segment 2023 and the projection of the second connecting segment 2033 are separated.

[0123] As shown in Figures 5 to 13, in some embodiments, the secondary battery includes a first adapter 50, through which the first connecting segment 2023 and the second connecting segment 2033 are electrically connected to the second portion 312. By adding the first adapter 50, the positions of the first tab 30, the first current collecting portion 202, and the second current collecting portion 203 can be flexibly arranged to meet different usage requirements of the secondary battery.

[0124] In some embodiments, as shown in Figure 6 or Figure 12, when observed along the third direction Z, the projection of the first collecting portion 202 and the projection of the second collecting portion 203 are both separated from the projection of the first electrode tab 30. In other words, the projection of the first connecting segment 2023 and the projection of the second connecting segment 2033 are both separated from the projection of the second portion 312.

[0125] Specifically, the plurality of first conductive segments 2021 , the first curved segments 2022 , the first connecting segment 2023 , the plurality of second conductive segments 2031 , the second curved segments 2032 and the second connecting segment 2033 are collectively enclosed to form a first installation space (not shown).

[0126] The first adapter 50 is a thin plate-like structure that extends generally along the second direction Y. A portion of the first adapter 50 is electrically connected to a surface of the second portion 312 facing the electrode assembly body 201. Another portion of the first adapter 50 passes through the first installation space and extends outside the first installation space. Another portion of the first adapter 50 is electrically connected to a surface of the second connecting section 2033 facing the electrode assembly body 201. The surface of the second connecting section 2033 facing away from the electrode assembly body 201 is electrically connected to a portion of the first connecting section 2023.

[0127] Of course, the first adapter 50 can also be electrically connected to the side surface of the first connecting section 2023 facing away from the electrode assembly body 201. At this time, the first adapter 50 no longer passes through the first installation space, and the first collecting part 202 and the second collecting part 203 are no longer bent separately to form the first installation space. Instead, the first collecting part 202 and the second collecting part 203 are bent separately to reduce the occupied space.

[0128] Furthermore, referring to the examples shown in Figures 7-10 in conjunction with Figure 11 , the first adapter 50 includes a first conductive layer 51 and a first insulating layer 52. The second connecting segment 2033 and the second portion 312 are both electrically connected to the first conductive layer 51 on one side facing the electrode assembly body 201. The first insulating layer 52 is formed on the surface of the first conductive layer 51 facing the first sidewall 112 and is secured to the plurality of first conductive segments 2021 and the plurality of second conductive segments 2031. The first insulating layer 52 is insulating and isolates the current collector of a different polarity from the first polarity member 211 on the electrode assembly body 201 from the first polarity member 211, thereby reducing short circuits within the secondary battery. Furthermore, due to its inherent structural characteristics, the first insulating layer 52 offers greater structural strength than the first conductive layer 51, thus minimizing damage to the electrode plates in the electrode assembly body 201 when the electrode assembly 20 is assembled into the housing.

[0129] The material of the first conductive layer 51 is diverse and is not specifically limited in the embodiments of this application. Examples of such materials include metals, including aluminum, copper, nickel, titanium, copper-nickel alloys, aluminum-copper alloys, and stainless steel. For example, the first conductive layer 51 can be made of aluminum, the same material as the first polar element 211.

[0130] In some embodiments, a side surface of the second connecting segment 2033 facing the electrode assembly body 201 and a side surface of the second portion 312 facing the electrode assembly body 201 are both welded and fixed to the first conductive layer 51 .

[0131] Alternatively, the second connecting segment 2033 and the first connecting segment 2023 are both superimposed on the surface of the first adapter 50 facing away from the main body. Furthermore, when viewed along the third direction Z, the projection of the second connecting segment 2033 is separated from the projection of the first connecting segment 2023. Specifically, the side surface of the second connecting segment 2033 facing the electrode assembly body 201 and the side surface of the first connecting segment 2023 facing the electrode assembly body 201 are both welded to the first conductive layer 51.

[0132] The material of the first insulating layer 52 is actually diverse and is not specifically limited in the embodiments of this application. Examples of such materials include adhesive insulating materials or non-adhesive insulating materials. The adhesive insulating material may include at least one of polypropylene, polyethylene, butyl rubber, acrylic glue, modified polyolefin, a copolymer of styrene and butadiene, and acrylic glue.

[0133] In some embodiments, the first insulating layer 52 is bonded and fixed to the first conductive segments 2021 and the second conductive segments 2031 . Of course, the first insulating layer 52 can also be suspended above the first conductive segments 2021 and the second conductive segments 2031 .

[0134] As shown in Figures 11 or 14 , in some embodiments, the thickness T2 of the first insulating layer 52 in the third direction Z is 0.01 mm ≤ T2 ≤ 0.2 mm, and the thickness T3 of the first conductive layer 51 in the third direction Z is 0.05 mm ≤ T3 ≤ 2 mm. Within this range, the overall structural strength of the first adapter 50 is maintained while the maximum thickness of the first adapter 50 can be less than or equal to the width of the first installation space in the third direction Z. This configuration can further reduce the gap between the electrode assembly body 201 and the first sidewall 112. Preferably, 0.02 mm ≤ T2 ≤ 0.15 mm, and 0.15 mm ≤ T3 ≤ 0.35 mm.

[0135] As shown in Figures 5 to 13, in some embodiments, the plurality of second polarity members 221 include at least two third sub-polarity members (not shown) and at least two fourth sub-polarity members (not shown). The at least two third sub-polarity members converge toward the first end wall 111 and overlap to form a third current collecting portion 204, and the at least two fourth sub-polarity members converge toward the second end wall 121 and overlap to form a fourth current collecting portion 205. The third current collecting portion 204 and the fourth current collecting portion 205 are both electrically connected to the fourth portion 412.

[0136] Specifically, the third current collecting portion 204 comprises at least two third conductive segments 2041, a third curved segment 2042, and a third connecting segment 2043. The at least two third conductive segments 2041 extend from the electrode assembly body 201. The at least two third conductive segments 2041 converge toward the first end wall 111 and overlap in a direction opposite to the third direction Z. The third connecting segment 2043 is connected to the at least two third conductive segments 2041 via the third curved segment 2042. The third connecting segment 2043 is electrically connected to the fourth portion 412. The third conductive segment 2041 is the portion of a single third sub-polarity member that extends outside the second pole piece body and connects to an adjacent third sub-polarity member. The third curved segment 2042 is formed by bending the interconnected portions of multiple third sub-polarity members away from the first end wall 111. The third connecting segment 2043 is formed by extending the end of the third curved segment 2042 away from the third conductive segment 2041 away from the third curved segment 2042.

[0137] The fourth current collecting portion 205 comprises at least two fourth conductive segments 2051, a fourth curved segment 2052, and a fourth connecting segment 2053. At least two fourth conductive segments 2051 extend from the electrode assembly body 201. The at least two fourth conductive segments 2051 converge toward the second end wall 121 and overlap in a direction opposite to the third direction Z. The fourth connecting segment 2053 connects to the at least two fourth conductive segments 2051 via the fourth curved segment 2052. The curvature of the fourth curved segment 2052 is opposite to that of the third curved segment 2042. The fourth connecting segment 2053 is electrically connected to the fourth portion 412. The fourth conductive segment 2051 is the portion of a single fourth sub-polarity member that extends outside the second pole piece body and connects to an adjacent fourth sub-polarity member. The fourth curved segment 2052 is formed by bending the interconnected portions of multiple fourth sub-polarity members away from the second end wall 121. The fourth connecting segment 2053 is formed by extending from one end of the fourth curved segment 2052 away from the fourth conductive segment 2051 toward away from the fourth curved segment 2052 .

[0138] Based on a similar principle to the arrangement of the first and second sub-polarity members, the actual installation position of the second tab adhesive 42 deviates slightly from the intended installation position of the second tab adhesive 42 in the height direction (opposite to the third direction Z), thereby reducing wasted height space on the side where the second tab 40 is located, further increasing the capacity of the secondary battery. In particular, when the first tab 30 and the second tab 40 are located on the same side of the main body 101, since the specific structures of the multiple second polarity members 221 and the multiple first polarity members 211 are substantially the same, the overall wasted height space of the secondary battery can be reduced.

[0139] In some embodiments, the fourth portion 412, part of the third connecting segment 2043, and the fourth connecting segment 2053 are stacked in sequence, so that any two of the fourth portion 412, part of the third connecting segment 2043, and the fourth connecting segment 2053 can fully contact each other, thereby reducing the resistance at the connection between the three.

[0140] It should be noted that when the thickness of the electrode assembly body 201 in the first direction X is less than 4 mm, the end of the third connecting segment 2043 away from the third curved segment 2042 and the end of the fourth connecting segment 2053 away from the fourth curved segment 2052 need to be trimmed. After trimming, the electrical connection reliability of any two adjacent conductive segments in the overlapping area is improved. However, when the thickness of the electrode assembly body 201 in the first direction X is greater than or equal to 4 mm, the end of the third connecting segment 2043 away from the third curved segment 2042 and / or the end of the fourth connecting segment 2053 away from the fourth curved segment 2052 can be trimmed based on actual usage requirements.

[0141] Furthermore, the fourth portion 412, a portion of the third connecting segment 2043, and the fourth connecting segment 2053 are fixed together by welding. Since the fourth portion 412, a portion of the third connecting segment 2043, and the fourth connecting segment 2053 are stacked in sequence, there is no need to weld the third connecting segment 2043 and the fourth connecting segment 2053 to the fourth portion 412 separately. This can reduce the number of welding operations, thereby improving the production efficiency of the secondary battery.

[0142] As shown in FIG9 , in some embodiments, along the first direction X, the distance between the end of the third connecting segment 2043 away from the third curved segment 2042 and the fourth curved segment 2052 is D3 (in mm), and the thickness of the electrode assembly body 201 in the first direction X is T1 (in mm), and the two satisfy the following relationship: 0.1 mm ≤ D3 ≤ T1. The mechanism for limiting the size of the third connecting segment 2043 is similar to that for limiting the size of the first connecting segment 2023 and will not be further described here.

[0143] Continuing with FIG. 9 , in some embodiments, along the first direction X, the distance between the end of the fourth connecting segment 2053 away from the fourth curved segment 2052 and the third curved segment 2042 is D4 (in mm), and the thickness of the electrode assembly body 201 along the first direction X is T1 (in mm), and both satisfy the following relationship: 0.1 mm ≤ D4 ≤ T1 / 2. The mechanism for limiting the size of the fourth connecting segment 2053 is similar to that for limiting the size of the second connecting segment 2033 and will not be further elaborated here.

[0144] Of course, the connection method between the fourth portion 412, the third connecting segment 2043, and the fourth connecting segment 2053 is not limited to this, and it is sufficient that all of them are electrically conductive with the fourth portion 412. For example, in other embodiments, the fourth portion 412, part of the third connecting segment 2043, and the fourth connecting segment 2053 are sequentially stacked. For another example, in other embodiments, the fourth connecting segment 2053 and the third connecting segment 2043 are respectively in contact with the fourth portion 412, and when viewed along the third direction Z, the projection of the first connecting segment 2023 and the projection of the second connecting segment 2033 are separated.

[0145] As shown in Figures 5 to 13, in some embodiments, the secondary battery includes a second adapter 60, and the third connecting segment 2043 and the fourth connecting segment 2053 are electrically connected to the fourth portion 412 via the second adapter 60. By adding the second adapter 60, the positions of the second tab 40, the third current collecting portion 204, and the fourth current collecting portion 205 can be flexibly arranged to meet different usage requirements of the secondary battery.

[0146] In some embodiments, as shown in Figure 6 or Figure 13, when observing along the third direction Z, the projection of the third collecting portion 204 and the projection of the fourth collecting portion 205 are both separated from the projection of the second pole ear 40. In other words, the projection of the third connecting segment 2043 and the projection of the fourth connecting segment 2053 are both separated from the projection of the fourth portion 412.

[0147] Specifically, the plurality of third conductive segments 2041 , the third curved segments 2042 , the third connecting segment 2043 , the plurality of fourth conductive segments 2051 , the fourth curved segments 2052 , and the fourth connecting segment 2053 are collectively enclosed to form a second installation space.

[0148] The second adapter 60 is a thin plate-like structure that extends generally in a direction opposite to the second direction Y. A portion of the second adapter 60 is electrically connected to a surface of the fourth portion 412 facing the electrode assembly body 201. Another portion of the second adapter 60 passes through the second installation space and extends outside the second installation space. Another portion of the second adapter 60 is electrically connected to a surface of the fourth connecting segment 2053 facing the electrode assembly body 201. The surface of the fourth connecting segment 2053 facing away from the electrode assembly body 201 is electrically connected to a portion of the third connecting segment 2043.

[0149] Of course, the second adapter 60 can also be electrically connected to the side surface of the third connecting section 2043 facing away from the electrode assembly body 201. At this time, the second adapter 60 no longer passes through the second installation space, and the third collecting part 204 and the fourth collecting part 205 are no longer bent separately to form the second installation space. Instead, the third collecting part 204 and the fourth collecting part 205 are bent separately to reduce the occupied space.

[0150] Furthermore, referring to the examples shown in Figures 7-10 in conjunction with Figure 11 , the second adapter 60 includes a second conductive layer 61 and a second insulating layer 62. The surface of the fourth connecting segment 2053 facing the electrode assembly body 201 and the surface of the fourth portion 412 facing the electrode assembly body 201 are both electrically connected to the second conductive layer 61. The second insulating layer 62 is formed on the surface of the second conductive layer 61 facing the first sidewall 112 and is secured to the plurality of third conductive segments 2041 and the plurality of fourth conductive segments 2051, respectively. The second insulating layer 62 has insulating properties, isolating the current collectors of different polarity from the second polarity member 221 on the electrode assembly body 201 from the second polarity member 221, thereby reducing short circuits within the secondary battery. Furthermore, due to its inherent structural characteristics, the second insulating layer 62 offers greater structural strength than the second conductive layer 61, thus minimizing damage to the electrode plates in the electrode assembly body 201 when the electrode assembly 20 is assembled into the housing.

[0151] Of course, the second adapter 60 can only be provided with the second conductive layer 61. This is because the second adapter 60 is connected to the second polarity member 221 with a negative polarity, and the electrode assembly body 201 is based on the perspective of improving the short circuit of the positive and negative electrode sheets, so that the four sides of the negative electrode sheet extend beyond the four sides of the positive electrode sheet, and even if the second conductive layer 61 contacts the four sides of the negative electrode sheet, it will not be short-circuited.

[0152] The material choices for the second conductive layer 61 are diverse and are not specifically limited in the various embodiments of this application. Examples of such materials include metals, including aluminum, copper, nickel, titanium, copper-nickel alloys, aluminum-copper alloys, and stainless steel. For example, the second conductive layer 61 can be made of copper, the same material as the second polarity member 221.

[0153] In some embodiments, a side surface of the fourth connecting segment 2053 facing the electrode assembly body 201 and a side surface of the fourth portion 412 facing the electrode assembly body 201 are both welded and fixed to the second conductive layer 61 .

[0154] Alternatively, the fourth connecting segment 2053 and the third connecting segment 2043 are both superimposed on the surface of the second adapter 60 facing away from the main body. Furthermore, when viewed along the third direction Z, the projection of the fourth connecting segment 2053 is separated from the projection of the third connecting segment 2043. Specifically, the side surface of the fourth connecting segment 2053 facing the electrode assembly body 201 and the side surface of the third connecting segment 2053 facing the electrode assembly body 201 are both welded to the second conductive layer 61.

[0155] The material of the second insulating layer 62 is actually diverse and is not specifically limited in the embodiments of this application. Examples of such materials include a second adhesive insulating material or a non-adhesive insulating material. The second adhesive insulating material may include at least one of polypropylene, polyethylene, butyl rubber, acrylic glue, modified polyolefin, a copolymer of styrene and butadiene, and acrylic glue.

[0156] In some embodiments, the second insulating layer 62 is bonded and fixed to the third conductive segments 2041 and the fourth conductive segments 2051 . Of course, the second insulating layer 62 can also be suspended above the third conductive segments 2041 and the fourth conductive segments 2051 .

[0157] As shown in Figures 11 or 14 , in some embodiments, the thickness T4 of the second insulating layer 62 in the third direction Z is 0.01 mm ≤ T4 ≤ 0.2 mm, and the thickness T5 of the second conductive layer 61 in the third direction Z is 0.05 mm ≤ T5 ≤ 2 mm. Within this numerical range, the overall structural strength of the second adapter 60 is maintained while the maximum thickness of the second adapter 60 can be less than or equal to the width of the second installation space in the third direction Z. This configuration can further reduce the gap between the electrode assembly body 201 and the first sidewall 112. Preferably, 0.02 mm ≤ T4 ≤ 0.15 mm and 0.15 mm ≤ T5 ≤ 0.35 mm.

[0158] Furthermore, as shown in Figure 14, the second insulating layer 62 is integrally connected to the first insulating layer 52, and the second conductive layer 61 does not contact the first conductive layer 51. The advantage of this arrangement is that when the first polarity member 211 and the second polarity member 221 have similar structures, the first adapter 50 and the second adapter 60 can be a single integral component, thereby reducing the number of components required to assemble the secondary battery and improving the assembly efficiency of the secondary battery.

[0159] In some embodiments, the length of the first tab glue extending beyond the first sealing portion in a direction opposite to the third direction Z is 0 mm to 1.7 mm. Furthermore, the length of the second tab glue extending beyond the first sealing portion in a direction opposite to the third direction Z is 0 mm to 1.7 mm. Compared to related art techniques in which both the length of the first tab glue extending beyond the first sealing portion and the length of the second tab glue extending beyond the first sealing portion are 0 mm to 2.5 mm, the first and second tab glues in this application extend much shorter, thereby occupying less space and improving the space utilization of the secondary battery.

[0160] One embodiment of the present application further provides an electronic device comprising any of the above-mentioned secondary batteries. The electronic device of the present application may include, but is not limited to, a laptop computer, a pen-type computer, a mobile computer, an e-book player, a portable phone, a portable fax machine, a portable copier, a portable printer, a head-mounted stereo headset, a video recorder, an LCD television, a portable cleaner, a portable CD player, a mini-disc, a transceiver, an electronic notepad, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, an automobile, a motorcycle, a power-assisted bicycle, a lighting fixture, a toy, a game console, a clock, a power tool, a flashlight, a camera, a large household battery, and a lithium-ion capacitor.

[0161] The above description is merely an embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A secondary battery comprising a packaging bag, an electrode assembly, and a first tab, wherein the packaging bag comprises a main body and a first sealing portion, the electrode assembly is accommodated in the main body, the main body comprises a first end wall, a second end wall, and a first side wall, wherein the first end wall and the second end wall are oppositely disposed along a first direction, the first side wall is connected between the first end wall and the second end wall, and the first sealing portion is connected to the first side wall; The first tab includes a first metal strip and a first tab glue surrounding the first metal strip, and the first metal strip is fixed to the first sealing portion by the first tab glue; The electrode assembly includes an electrode assembly body and a plurality of first polarity parts extending from the electrode assembly body, the plurality of first polarity parts include at least two first sub-polarity parts and at least two second sub-polarity parts, the at least two first sub-polarity parts are gathered toward the first end wall and stacked to form a first collecting part, the at least two second sub-polarity parts are gathered toward the second end wall and stacked to form a second collecting part, and the second collecting part and the first collecting part are both electrically connected to the first metal strip.

2. The secondary battery according to claim 1, wherein A gap is formed between the first side wall and the electrode assembly body, and the secondary battery includes a first adapter, and the first adapter is located in the gap; The first metal strip is electrically connected to the first current collecting portion and the second current collecting portion through the first adapter.

3. The secondary battery according to claim 2, wherein The first adapter extends along the second direction; When viewed along a third direction, a projection of the first collecting portion and a projection of the second collecting portion are both separated from a projection of the first metal strip, wherein any two of the third direction, the second direction and the first direction are perpendicular to each other.

4. The secondary battery according to claim 1, wherein The first current collecting portion comprises at least two first conductive segments, a first curved segment, and a first connecting segment. The at least two first conductive segments extend from the electrode assembly body and converge toward the first end wall. One end of the first connecting segment is connected to the at least two first conductive segments via the first curved segment, and the other end of the first connecting segment extends toward the second end wall. The second current collecting portion comprises at least two second conductive segments, a second curved segment, and a second connecting segment, wherein the at least two second conductive segments extend from the electrode assembly body and converge toward the second end wall, one end of the second connecting segment is connected to the at least two second conductive segments via the second curved segment, and the other end of the second connecting segment extends toward the first end wall, wherein the curvature direction of the second curved segment is opposite to that of the first curved segment; The first metal strip is electrically connected to the first connecting section and the second connecting section through the first adapter.

5. The secondary battery according to claim 4, wherein The at least two first conductive segments, the first curved segment, the first connecting segment, the at least two second conductive segments, the second curved segment, and the second connecting segment are collectively arranged to form a first installation space; The first adapter is partially accommodated in the first installation space and is electrically connected to the first connecting section and the second connecting section. The portion of the first adapter not accommodated in the first installation space is electrically connected to the first metal strip.

6. The secondary battery according to claim 5, characterized in that The second connecting section is overlapped with a surface of the first adapter facing away from the main body, and the first connecting section is at least partially overlapped with the second connecting section.

7. The secondary battery according to claim 5, characterized in that The second connecting section and the first connecting section are both superimposed on a surface of the first adapter facing away from the main body; and When viewed along the third direction, a projection of the second connecting segment is separated from a projection of the first connecting segment.

8. The secondary battery according to any one of claims 1 to 7, characterized in that: The ratio of the number of the first sub-polarity elements to the number of the second sub-polarity elements satisfies: 1:1 to 1:5; or The ratio of the number of the first sub-polarity elements to the number of the second sub-polarity elements satisfies: 1:1 to 5:

1.

9. The secondary battery according to any one of claims 2 to 6, characterized in that: The secondary battery includes a second tab, the second tab including a second metal strip and a second tab glue surrounding the second metal strip, the second metal strip being fixed to the first sealing portion by the second tab glue; The electrode assembly also includes a plurality of second polarity members extending from the electrode assembly body, the plurality of second polarity members including at least two third sub-polarity members and at least two fourth sub-polarity members, the at least two third sub-polarity members being gathered and stacked toward the first end wall to form a third current collecting portion, the at least two fourth sub-polarity members being gathered and stacked toward the second end wall to form a fourth current collecting portion, the fourth current collecting portion and the third current collecting portion being both electrically connected to the second metal strip.

10. The secondary battery according to claim 9, wherein The secondary battery includes a second adapter, and the second adapter is located in the gap; The second metal strip is electrically connected to the third current collecting portion and the fourth current collecting portion through the adapter.

11. The secondary battery according to claim 10, wherein The second adapter extends in a direction opposite to the second direction; When viewed along a third direction, a projection of the third collecting portion and a projection of the fourth collecting portion are both separated from a projection of the second metal strip, wherein any two of the third direction, the second direction and the first direction are perpendicular to each other.

12. The secondary battery according to claim 11, wherein The first adapter comprises a first conductive layer and a first insulating layer, wherein the first insulating layer is formed on a surface of the first conductive layer facing the first side wall; The first metal strip is electrically connected to the first power collecting portion and the second power collecting portion through the first conductive layer.

13. The secondary battery according to claim 12, characterized in that The second transition member includes a second conductive layer and a second insulating layer, wherein the second insulating layer is formed on a surface of the second conductive layer facing the first side wall; The second metal strip is electrically connected to the third power collecting portion and the fourth power collecting portion through the second conductive layer.

14. The secondary battery according to claim 13, wherein The second insulating layer is integrally connected to the first insulating layer, and the second conductive layer is not in contact with the first conductive layer.

15. The secondary battery according to claim 14, characterized in that The secondary battery satisfies at least one of the following conditions: (1) The first metal strip is welded and fixed to the first conductive layer; (2) the first current collecting portion is welded and fixed to the first conductive layer; (3) The second current collecting portion is welded and fixed to the first conductive layer; (4) The first insulating layer is made of a first adhesive insulating material, and the first insulating layer is adhesively fixed to the first collector portion and the second collector portion; (5) Along the third direction, the thickness of the first insulating layer is T2, 0.01 mm ≤ T2 ≤ 0.2 mm; (6) The first conductive layer is made of metal material; (7) Along the third direction, the thickness of the first conductive layer is T3, 0.01 mm ≤ T3 ≤ 2 mm; (8) The second metal strip is welded and fixed to the second conductive layer; (9) The third current collecting portion is welded and fixed to the second conductive layer; (10) The fourth current collecting portion is welded and fixed to the second conductive layer; (11) The second insulating layer is made of a second adhesive insulating material, and the second insulating layer is adhesively fixed to the third collector portion and the fourth collector portion; (12) Along the third direction, the thickness of the second insulating layer is T4, 0.01 mm ≤ T4 ≤ 0.2 mm; (13) The second conductive layer is made of metal material; (14) Along the third direction, the thickness of the second conductive layer is T5, 0.01 mm ≤ T5 ≤ 2 mm.

16. The secondary battery according to claim 9, characterized in that In a direction opposite to the third direction, the first tab glue extends out of the first sealing portion by a length of 0 mm to 1.7 mm; and in a direction opposite to the third direction, the second tab glue extends out of the first sealing portion by a length of 0 mm to 1.7 mm.

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

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