Secondary battery and electric device
By designing a second ear bundle shorter than the first ear bundle in the secondary battery and connecting it with the first electrode sheet, the capacity reduction and internal resistance increase caused by the break of the ear are solved, and the battery performance maintenance is achieved in the case of broken ears.
Patent Information
- Application Number
- CN202510258091.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-05
- Publication Date
- 2025-05-23
AI Technical Summary
When a multi-pole ear secondary battery is impacted or dropped, the pulling between the ear bundle and the adapter ear can easily lead to the ear breakage, which will lead to a decrease in the capacity of the secondary battery or an increase in internal resistance.
A secondary battery is designed, including a housing, an electrode assembly, a first ear bundle, a second ear bundle and a first adapter ear. The length of the second pole ear bundle is shorter than the first pole ear bundle and is connected to the first pole sheet, so as to act as a conductive function when the first pole ear bundle is broken.
Even if some of the first electrodes are broken, the second electrodes can still maintain conductive effects, ensuring that the capacity of the secondary battery is fully released and the internal resistance is reduced, and the battery performance is maintained.
Smart Images
Figure CN120033299A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the field of energy storage technology, and in particular relates to a secondary battery and electrical equipment. Background Art
[0002] At present, the tabs of multi-tab secondary batteries are usually gathered into tab bundles, which are then connected to adapter tabs, which are connected to the shell, and a portion of the adapter tabs extends out of the shell. When the secondary battery is impacted or dropped, the adapter tabs are stationary relative to the shell, while the electrode assembly and the tab bundles move relative to the shell, causing a pull between the tab bundles and the adapter tabs, which can easily lead to the breakage of some tabs. For multi-tab laminated secondary batteries, tab breakage will cause the corresponding pole piece to be unable to be connected to the external circuit, thereby causing a decrease in the capacity of the secondary battery. For multi-tab wound secondary batteries, tab breakage will increase the movement path of electrons, thereby increasing the internal resistance of the secondary battery. Summary of the invention
[0003] In view of the above situation, it is necessary to provide a secondary battery that can maintain performance when part of the tabs are broken.
[0004] The first aspect of the embodiment of the present application provides a secondary battery, which includes a housing, an electrode assembly, a first pole tab bundle, a second pole tab bundle and a first adapter pole tab. The electrode assembly includes a first pole piece, a second pole piece and a separator, the first pole piece and the second pole piece have opposite polarities, and the first pole piece, the separator and the second pole piece are stacked; the electrode assembly is accommodated in the housing. The first pole tab bundle is accommodated in the housing, the first pole tab bundle includes a plurality of first pole tabs, the plurality of first pole tabs are all connected to the first pole piece, the plurality of first pole tabs are connected to the end of the first pole piece and are arranged along the first direction, and the first direction is the thickness direction of the electrode assembly; the plurality of first pole tabs are stacked. The second pole tab bundle is accommodated in the housing, the length of the second pole tab bundle is shorter than the length of the first pole tab bundle, the second pole tab bundle includes a plurality of second pole tabs, the plurality of second pole tabs are all connected to the first pole piece, the plurality of second pole tabs are connected to the end of the first pole piece and are arranged along the first direction, and the plurality of second pole tabs are stacked. The first adapter pole tab is connected to the first pole tab bundle and extends out of the housing, and the first adapter pole tab is connected to the housing.
[0005] In this secondary battery, since the first pole piece is connected to the first pole tab bundle and the second pole tab bundle, and only the first pole tab bundle is connected to the first transfer pole tab, when the secondary battery is impacted or dropped, even if a part of the first pole tabs in the first pole tab bundle are broken, the second pole tab bundle can still play a conductive role. For a secondary battery with a laminated structure, the second pole tab bundle can maintain the connection between the multiple layers of first pole pieces, which is conducive to connecting all the first pole pieces to the circuit and fully releasing the capacity of the secondary battery; for a secondary battery with a winding structure, the second pole tab is conducive to shortening the movement path of electrons, thereby helping to reduce the internal resistance of the secondary battery. In summary, setting the second pole tab bundle is conducive to maintaining the performance of the secondary battery when a part of the first pole tab is broken. It should be noted that the length of the first pole tab bundle refers to the length of the first pole tab bundle after all the first pole tabs form the first pole tab bundle, along the extension direction of the first pole tab bundle, that is, the length of the first pole tab bundle in the expanded state, and the length of the second pole tab bundle refers to the length of the second pole tab bundle after all the second pole tabs form the second pole tab bundle, along the extension direction of the second pole tab bundle, that is, the length of the second pole tab bundle in the expanded state. The second pole tab bundle can electrically connect the pole pieces of each layer, so the second pole tab bundle can be made shorter, thereby improving the volume energy density and weight energy density of the secondary battery.
[0006] In one or more embodiments of the present application, the second pole lug bundle includes a first portion and a second portion, the second portion connects the electrode assembly and the first portion, and the first portion and the second portion are arranged at an angle. The first portion includes a first surface, the first surface faces the electrode assembly along a second direction, and the second direction is perpendicular to the first direction. In this way, the second pole lug bundle is in a bent state, which is conducive to reducing the occupation of the second pole lug bundle for the head space of the secondary battery, thereby facilitating the improvement of the energy density of the secondary battery.
[0007] In one or more embodiments of the present application, the electrode assembly includes a second surface and a third surface that are arranged opposite to each other along a first direction, and the projections of the first and second tab bundles along the second direction are located between the second and third surfaces. This helps to reduce the influence of the first and second tab bundles on the thickness of the secondary battery.
[0008] In one or more embodiments of the present application, a plurality of second tabs are welded to each other to form a first weld mark, and along the extension direction of the second tab bundle, the length of the first weld mark is L 1 , 2mm≤L 1 ≤9mm. Set L 1 ≥2mm, the length of the first weld mark is not too short, which is conducive to reducing the difficulty of welding and improving the connection stability between the second tabs; setting L 1 ≤9mm, the length of the first weld mark is not too long, which is beneficial to reducing the space occupied by the second tab bundle.
[0009] In one or more embodiments of the present application, 3.8 mm ≤ L 1 ≤4.5mm. Set L 1 ≥3.8mm, which is conducive to further reducing the difficulty of welding and further improving the connection stability between the second tabs; setting L 1 ≤4.5mm, which is conducive to further reducing the space occupied by the second tab bundle.
[0010] In one or more embodiments of the present application, the first weld mark extends in a straight line, so that the first weld mark is not bent, which is beneficial to maintaining the stability of the welding structure of the first weld mark.
[0011] In one or more embodiments of the present application, the first pole piece includes a first current collector, the first pole tab and the first current collector are an integral structure, and the second pole tab and the first current collector are an integral structure. The first pole tab bundle and the second pole tab bundle are arranged on the same side of the electrode assembly along the second direction, and the first pole tab bundle and the second pole tab bundle are arranged at intervals along the third direction; the first direction, the second direction and the third direction are perpendicular to each other. Along the third direction, the distance between the first pole tab bundle and the second pole tab bundle is D, 2mm≤D≤3mm. When D≥2mm is set, the distance between the first pole tab and the second pole tab bundle is not too small, which is conducive to reducing the possibility of mutual interference between the first pole tab and the second pole tab during the die-cutting process; when D≤3mm is set, the distance between the first pole tab and the second pole tab is not too large, which is conducive to reducing the influence of the setting of the first pole tab and the second pole tab on the width of the secondary battery.
[0012] In one or more embodiments of the present application, along the extension direction of the second tab bundle, the length of the second tab bundle is L 2 , 3mm≤L 2 ≤9mm. Set L 2 ≥3mm, the length of the second pole ear bundle is not too short, and the length of the second pole ear is not too short, which is conducive to reducing the difficulty of connecting the second pole ears; setting L 2 ≤9mm, the length of the second tab bundle is not too long, which is beneficial to reducing the space occupied by the second tab bundle in the shell and is beneficial to improving the energy density of the secondary battery.
[0013] In one or more embodiments of the present application, 3 mm ≤ L 2 ≤5mm. Set L 2 ≤5mm, which is beneficial to further reduce the space occupied by the second tab bundle in the shell.
[0014] In one or more embodiments of the present application, the second tab bundle is disposed on one side of the electrode assembly along the second direction, and along the third direction, the width of the second tab bundle is W 1 , 3mm≤W 1≤4mm; the first direction, the second direction and the third direction are perpendicular to each other. Set W 1 ≥3mm, the width of the second tab bundle is not too small, which is beneficial to improve the current carrying capacity of the second tab bundle; set W 1 ≤4mm, the width of the second tab bundle is not too large, which is beneficial to reducing the influence of the second tab bundle on the width of the secondary battery.
[0015] In one or more embodiments of the present application, along the extension direction of the first tab bundle, the length of the first tab bundle is L 3 , 8mm≤L 3 ≤10mm. Set L 3 ≥8mm, the length of the first pole ear bundle is not too short, and the length of the first pole ear is not too short, which is conducive to reducing the difficulty of connecting the first pole ears; setting L 3 ≤10mm, the length of the first tab bundle is not too long, which is beneficial to reducing the space occupied by the first tab bundle in the shell and is beneficial to improving the energy density of the secondary battery.
[0016] In one or more embodiments of the present application, the first tab bundle is disposed on one side of the electrode assembly along the second direction, and along the third direction, the width of the first tab bundle is W 2 , 3mm≤W 2 ≤4mm; the first direction, the second direction and the third direction are perpendicular to each other. Set W 2 ≥3mm, the width of the first pole lug bundle is not too small, which is beneficial to improve the current carrying capacity of the first pole lug bundle; setting W 2 ≤4mm, the width of the first tab bundle is not too large, which is beneficial to reducing the influence of the first tab bundle on the width of the secondary battery.
[0017] In one or more embodiments of the present application, the shell includes a first protective layer, a metal layer, and a second protective layer, the metal layer is sandwiched between the first protective layer and the second protective layer, and the first protective layer faces the inside of the shell. The secondary battery includes a first adhesive, a plurality of second pole tabs are welded to each other to form a first weld mark, a plurality of first pole tabs are welded to each other to form a second weld mark, a first transfer pole tab is welded to the first pole tab bundle to form a third weld mark, and the first adhesive covers at least one of the first weld mark, the second weld mark, or the third weld mark. The first adhesive is provided to reduce the possibility of the first protective layer being pierced by burrs generated during the welding process, thereby reducing the possibility of corrosion of the shell.
[0018] In one or more embodiments of the present application, the length of the first tab bundle 30 along the extension direction of the first tab bundle 30 is L 3， Along the extension direction of the second tab bundle 40, the length of the second tab bundle 40 is L 2 , L 2 , L3 Meet L 2 <L 3 Since the second tab bundle 40 does not need to consider the transfer tab, the second tab bundle can be made shorter, saving materials and space.
[0019] In one or more embodiments of the present application, the second tab bundle is contained in the shell and is not led out of the shell. The second tab bundle does not need to be extended out of the shell, which can improve the volume energy density and weight energy density of the secondary battery.
[0020] In one or more embodiments of the present application, the secondary battery includes a third pole lug bundle, a fourth pole lug bundle, and a second adapter pole lug. The third pole lug bundle is accommodated in the housing, the third pole lug bundle includes a plurality of third pole lugs, the plurality of third pole lugs are all connected to the second pole piece, the ends of the plurality of third pole lugs connected to the second pole piece are arranged along the first direction; the plurality of third pole lugs are stacked. The fourth pole lug bundle is accommodated in the housing, the fourth pole lug bundle includes a plurality of fourth pole lugs, the plurality of fourth pole lugs are all connected to the second pole piece, the ends of the plurality of fourth pole lugs connected to the second pole piece are arranged along the first direction, and the plurality of fourth pole lugs are stacked. The second adapter pole lug is connected to the third pole lug bundle, part of the second adapter pole lug extends out of the housing, and the second adapter pole lug is connected to the housing. Since the second pole piece is connected to the third pole lug bundle and the fourth pole lug bundle, and only the third pole lug bundle is connected to the second adapter pole lug, when the secondary battery is impacted or dropped, even if a part of the third pole lugs in the third pole lug bundle are broken, the fourth pole lug bundle can still play a conductive role. For secondary batteries with a stacked structure, the fourth pole lug bundle is conducive to connecting all the second pole pieces to the circuit, which is conducive to fully releasing the capacity of the secondary battery; for secondary batteries with a wound structure, the fourth pole lug is conducive to shortening the movement path of electrons, thereby helping to reduce the internal resistance of the secondary battery. In summary, the fourth pole lug bundle is conducive to maintaining the performance of the secondary battery when some of the third pole lugs are broken.
[0021] A second aspect of the embodiments of the present application further provides an electrical device, which includes a secondary battery as described in any of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 It is a schematic structural diagram of a secondary battery in one embodiment of the present application.
[0023] Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure at II-II.
[0024] Figure 3 yes Figure 1 Schematic diagram of the cross-sectional structure at III-III in the figure.
[0025] Figure 4It is a partial structural schematic diagram of a secondary battery in one embodiment of the present application.
[0026] Figure 5 It is a partial structural schematic diagram of a secondary battery in one embodiment of the present application.
[0027] Figure 6 yes Figure 1 Schematic diagram of the cross-sectional structure at VI-VI in the figure.
[0028] Figure 7 yes Figure 1 Schematic diagram of the cross-sectional structure at VII-VII.
[0029] Figure 8 It is a schematic diagram of the structure of an electrical device in an embodiment of the present application.
[0030] Main component symbols 100 secondary battery; 10 shell; 11 first protective layer; 12 metal layer; 13 second protective layer; 20 electrode assembly; 21 first pole piece; 211 first current collector; 22 second pole piece; 23 isolation film; 20a second side; 20b third side; 30 first pole lug bundle; 31 first pole lug; 30a second weld mark; 40 second pole lug bundle; 41 second pole lug; 42 first part; 43 second part; 40a first side; 40b first weld mark; 40c welding point; 50 first transfer pole lug; 50a third weld mark; 60 third pole lug bundle; 61 third pole lug; 70 fourth pole lug bundle; 71 fourth pole lug; 80 second transfer pole lug; 90 first adhesive; 91 first adhesive portion; 92 second adhesive portion; 1000 electrical equipment; X first direction; Y second direction; Z third direction.
[0031] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION
[0032] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.
[0033] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be a centrally disposed element at the same time. When an element is considered to be "disposed on" another element, it may be directly disposed on the other element or there may be a centrally disposed element at the same time.
[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.
[0035] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.
[0036] In the description of the embodiments of the present application, the term "perpendicular" is used to describe an ideal state between two components. In actual production or use, there may be a state that is approximately perpendicular between the two components. The two components described as "perpendicular" may not be absolutely straight lines or planes, but may be roughly straight lines or planes. From a macroscopic point of view, if the overall extension direction is a straight line or a plane, the components can be considered to be "straight lines" or "planes".
[0037] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. The various embodiments in the present application may be combined with each other in the absence of conflict.
[0038] The embodiment of the present application provides a secondary battery, which includes a shell, an electrode assembly, a first pole lug bundle, a second pole lug bundle and a first adapter pole lug. The electrode assembly includes a first pole piece, a second pole piece and a separator, the first pole piece and the second pole piece have opposite polarities, and the first pole piece, the separator and the second pole piece are stacked; the electrode assembly is accommodated in the shell. The first pole lug bundle is accommodated in the shell, the first pole lug bundle includes a plurality of first pole lugs, the plurality of first pole lugs are all connected to the first pole piece, the plurality of first pole lugs are connected to the end of the first pole piece and are arranged along the first direction, and the first direction is the thickness direction of the electrode assembly; the plurality of first pole lugs are stacked. The second pole lug bundle is accommodated in the shell, the length of the second pole lug bundle is shorter than the length of the first pole lug bundle, the second pole lug bundle includes a plurality of second pole lugs, the plurality of second pole lugs are all connected to the first pole piece, the plurality of second pole lugs are connected to the end of the first pole piece and are arranged along the first direction, and the plurality of second pole lugs are stacked. The first adapter pole lug is connected to the first pole lug bundle and extends out of the shell, and the first adapter pole lug is connected to the shell.
[0039] In this secondary battery, since the first pole piece is connected to the first pole lug bundle and the second pole lug bundle, and only the first pole lug bundle is connected to the first transfer pole lug, when the secondary battery is impacted or dropped, even if a part of the first pole lugs in the first pole lug bundle are broken, the second pole lug bundle can still play a conductive role. For a secondary battery with a laminated structure, the second pole lug bundle can maintain the connection between multiple layers of first pole pieces, which is beneficial for connecting all the first pole pieces to the circuit and fully releasing the capacity of the secondary battery; for a secondary battery with a winding structure, the second pole lug is beneficial for shortening the movement path of electrons, thereby helping to reduce the internal resistance of the secondary battery. In summary, the provision of the second pole lug bundle is beneficial for maintaining the performance of the secondary battery when a part of the first pole lug is broken. The second pole lug bundle can electrically connect the pole pieces of each layer, so the second pole lug bundle can be made shorter, thereby improving the volume energy density and weight energy density of the secondary battery.
[0040] The embodiments of the present application are further described below in conjunction with the accompanying drawings.
[0041] like Figure 1 and Figure 2 As shown, an embodiment of the present application provides a secondary battery 100 , which includes a housing 10 and an electrode assembly 20 , wherein the electrode assembly 20 is accommodated in the housing 10 .
[0042] In some embodiments, the housing 10 is a flexible packaging bag, such as an aluminum-plastic film.
[0043] In some embodiments, the housing 10 is a hard shell, such as a plastic shell, or a metal shell including at least one of a steel alloy, an aluminum alloy, and a copper alloy.
[0044] In some embodiments, Figure 2 As shown, the electrode assembly 20 includes a first electrode sheet 21, a second electrode sheet 22 and a separator 23, and the first electrode sheet 21, the separator 23 and the second electrode sheet 22 are stacked. The polarities of the first electrode sheet 21 and the second electrode sheet 22 are opposite. Specifically, one of the first electrode sheet 21 and the second electrode sheet 22 is a positive electrode sheet, and the other is a negative electrode sheet.
[0045] In some embodiments, the first pole piece 21 , the isolation film 23 , and the second pole piece 22 are stacked in sequence and then wound to form a winding structure.
[0046] In some embodiments, a plurality of first pole pieces 21 , isolation films 23 , and a plurality of second pole pieces 22 are alternately stacked to form a stacked structure.
[0047] In some embodiments, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer that are stacked.
[0048] In some embodiments, the positive electrode current collector is a metal foil. As an illustrative example, the positive electrode current collector can be a metal foil including at least one of aluminum, nickel, tantalum, and titanium, such as aluminum foil.
[0049] In some embodiments, the positive electrode current collector is a composite current collector.
[0050] In some embodiments, the positive electrode active material layer includes a positive electrode active material. As an illustrative example, the positive electrode active material includes at least one of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium manganese iron phosphate, or lithium manganese oxide.
[0051] In some embodiments, the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer that are stacked.
[0052] In some embodiments, the negative electrode current collector is a metal foil. As an illustrative example, the negative electrode current collector can be a metal foil including at least one of copper, nickel, tantalum, and titanium, such as copper foil.
[0053] In some embodiments, the negative electrode current collector is a composite current collector.
[0054] In some embodiments, the negative electrode active material layer includes a negative electrode active material. As an illustrative example, the negative electrode active material includes at least one of graphite, hard carbon, soft carbon, silicon, silicon-oxygen material, and silicon-carbon material.
[0055] In some embodiments, the isolation film 23 is one of a polyethylene film, a polypropylene film, a polyester film, or a polyimide film.
[0056] In some embodiments, the secondary battery 100 includes an electrolyte, and the electrolyte is contained in the housing 10 .
[0057] In some embodiments, the electrolyte includes an electrolyte salt. The electrolyte salt includes at least one of an organic lithium salt or an inorganic lithium salt.
[0058] In some embodiments, the electrolyte salt is not limited to lithium hexafluorophosphate (LiPF 6 ), bis(trifluoromethanesulfonyl)imide lithium LiN (CF 3 SO 2 ) 2 (LiTFSI), lithium bis(fluorosulfonyl)imide Li(N(SO 2 F) 2 )(LiFSI), lithium hexafluorocesium oxide (LiCsF 6 ), lithium perchlorate (LiClO 4 ) or lithium trifluoromethanesulfonate (LiCF 3 SO 3 ) at least one of.
[0059] In some embodiments, Figure 2 and Figure 3 As shown, the secondary battery 100 includes a first pole tab bundle 30 and a second pole tab bundle 40 accommodated in the housing 10, and the length of the second pole tab bundle 40 is shorter than the length of the first pole tab bundle 30. The first pole tab bundle 30 includes a plurality of first pole tabs 31, and the plurality of first pole tabs 31 are connected to the first pole sheet 21, and the plurality of first pole tabs 31 are connected to the end of the first pole sheet 21 and arranged along the first direction X, and the first direction X is the thickness direction of the electrode assembly 20; the plurality of first pole tabs 31 are stacked. The second pole tab bundle 40 includes a plurality of second pole tabs 41, and the plurality of second pole tabs 41 are connected to the first pole sheet 21, and the plurality of second pole tabs 41 are connected to the end of the first pole sheet 21 and arranged along the first direction X, and the plurality of second pole tabs 41 are stacked. Specifically, for the secondary battery 100 with a stacked structure, each first pole sheet 21 is connected to a first pole ear 31 and a second pole ear 41, and the first pole ears 31 of different layers are gathered along the first direction X to form a first pole ear bundle 30, and the second pole ears 41 of different layers are gathered along the first direction X to form a second pole ear bundle 40; for the secondary battery 100 with a wound structure, a plurality of first pole ears 31 and a plurality of second pole ears 41 are connected to a first pole sheet 21. After the first pole sheet 21 is wound, the first pole ears 31 are arranged along the first direction X, and the second pole sheets 22 are arranged along the second direction Y. The first pole ears 31 of different layers are gathered along the first direction X to form a first pole ear bundle 30, and the second pole ears 41 of different layers are gathered along the first direction X to form a second pole ear bundle 40. It should be noted that the length of the first pole tab bundle 30 refers to the length of the first pole tab bundle 30 in an expanded state after all the first pole tabs 31 form the first pole tab bundle 30, and the length of the second pole tab bundle 40 refers to the length of the second pole tab bundle 40 in an expanded state after all the second pole tabs 41 form the second pole tab bundle 40. The second pole tab bundle 40 can electrically connect the pole sheets of each layer, so the second pole tab bundle 40 can be made shorter, thereby improving the volume energy density and weight energy density of the secondary battery 100.
[0060] In some embodiments, Figure 1 and Figure 2 As shown, the secondary battery 100 includes a first transfer tab 50 , which is connected to the first tab bundle 30 and extends out of the housing 10 , and the first transfer tab 50 is connected to the housing 10 .
[0061] In this secondary battery 100, since the first pole piece 21 is connected to the first pole tab bundle 30 and the second pole tab bundle 40, and only the first pole tab bundle 30 is connected to the first transfer pole tab 50, when the secondary battery 100 is impacted or dropped, even if a part of the first pole tabs 31 in the first pole tab bundle 30 are broken, the second pole tab bundle 40 can still play a conductive role. For the secondary battery 100 with a laminated structure, the second pole tab bundle 40 can maintain the connection between the multiple layers of the first pole pieces 21, which is conducive to connecting all the first pole pieces 21 to the circuit and fully releasing the capacity of the secondary battery 100; for the secondary battery 100 with a wound structure, the second pole tab 41 is conducive to shortening the moving path of electrons, thereby helping to reduce the internal resistance of the secondary battery 100. In summary, the second pole tab bundle 40 is provided to help maintain the performance of the secondary battery 100 when a part of the first pole tabs 31 are broken.
[0062] In some embodiments, Figure 3 As shown, the second tab bundle 40 includes a first portion 42 and a second portion 43, the second portion 43 connects the electrode assembly 20 and the first portion 42, and the first portion 42 and the second portion 43 are arranged at an angle. The first portion 42 includes a first surface 40a, and the first surface 40a faces the electrode assembly 20 along a second direction Y, and the second direction Y is perpendicular to the first direction X. In this way, the second tab bundle 40 is in a bent state, which is conducive to reducing the occupation of the second tab bundle 40 for the head space of the secondary battery 100, thereby facilitating the improvement of the energy density of the secondary battery 100.
[0063] In some embodiments, Figure 2 As shown, the first tab bundle 30 is bent into a U-shape to reduce the occupation of the head space of the secondary battery 100 by the first tab bundle 30 , thereby facilitating the improvement of the energy density of the secondary battery 100 .
[0064] In some embodiments, Figure 2 and Figure 3 As shown, the electrode assembly 20 includes a second surface 20a and a third surface 20b that are arranged opposite to each other along the first direction X, and the projections of the first tab bundle 30 and the second tab bundle 40 along the second direction Y are located between the second surface 20a and the third surface 20b. In this way, it is helpful to reduce the influence of the first tab bundle 30 and the second tab bundle 40 on the thickness of the secondary battery 100.
[0065] In some embodiments, Figure 3 and Figure 4 As shown, a plurality of second tabs 41 are welded to each other to form a first weld mark 40b. Along the extension direction of the second tab bundle 40, the length of the first weld mark 40b is L. 1 , 2mm≤L 1≤9mm. The extension direction of the second tab bundle 40 corresponds to its length direction in the flattened state. The first weld mark 40b refers to the area where the weld point 40c formed during the welding process of the second tab 41 is located. Figure 4 The first weld mark 40b is indicated by a dotted line. The length of the first weld mark 40b refers to the maximum distance between the two weld points 40c that are farthest apart in the first weld mark 40b along the extension direction of the second tab bundle 40. Here, the maximum distance refers to the distance including the size of the two weld points involved in the measurement. Set L 1 ≥2mm, the length of the first weld mark 40b is not too short, which is conducive to reducing the difficulty of welding and improving the connection stability between the second tabs 41; setting L 1 ≤9mm, the length of the first weld mark 40b is not too long, which is beneficial to reducing the space occupied by the second tab bundle 40.
[0066] In some embodiments, 3.8 mm ≤ L 1 ≤4.5mm. Set L 1 ≥3.8mm, which is conducive to further reducing the difficulty of welding and further improving the connection stability between the second tabs 41; setting L 1 ≤4.5 mm, which is beneficial to further reduce the space occupied by the second tab bundle 40.
[0067] In some embodiments, the first weld mark 40b extends in a straight line, that is, the first weld mark 40b is not bent, which is conducive to maintaining the stability of the welding structure of the first weld mark 40b.
[0068] In some embodiments, Figure 3 and Figure 4As shown, the first pole piece 21 includes a first current collector 211, the first pole tab 31 and the first current collector 211 are an integral structure, and the second pole tab 41 and the first current collector 211 are an integral structure. The first pole tab bundle 30 and the second pole tab bundle 40 are arranged on the same side of the electrode assembly 20 along the second direction Y, and the first pole tab bundle 30 and the second pole tab bundle 40 are arranged at intervals along the third direction Z; the first direction X, the second direction Y and the third direction Z are perpendicular to each other. Along the third direction Z, the distance between the first pole tab bundle 30 and the second pole tab bundle 40 is D, 2mm≤D≤3mm. Here, the first pole tab 31 and the first current collector 211 are an integrated structure, which means that the first pole tab 31 and the first current collector 211 are different parts of the same material, and during preparation, the first pole tab 31 is formed by die-cutting the material of the first current collector 211; the second pole tab 41 and the first current collector 211 are an integrated structure, which means that the second pole tab 41 and the second current collector are different parts of the same material, and during preparation, the second pole tab 41 is formed by die-cutting the material of the second current collector. When D is set to ≥ 2 mm, the distance between the first pole tab 31 and the second pole tab bundle 40 is not too small, which is conducive to reducing the possibility of mutual interference between the first pole tab 31 and the second pole tab 41 during the die-cutting process; when D is set to ≤ 3 mm, the distance between the first pole tab 31 and the second pole tab 41 is not too large, which is conducive to reducing the influence of the setting of the first pole tab 31 and the second pole tab 41 on the width of the secondary battery 100.
[0069] In some embodiments, Figure 4 As shown, along the extension direction of the second tab bundle 40, the length of the second tab bundle 40 is L 2 , 3mm≤L 2 ≤9mm. Set L 2 ≥3mm, the length of the second pole ear bundle 40 is not too short, and the length of the second pole ear 41 is not too short, which is conducive to reducing the difficulty of connecting the second pole ears 41; setting L 2 ≤9mm, the length of the second tab bundle 40 is not too long, which is beneficial to reduce the space occupied by the second tab bundle 40 in the housing 10, and is beneficial to improve the energy density of the secondary battery 100. When measuring the length of the second tab bundle 40, the second tab bundle 40 can be cut off from the first pole sheet 21, and then the second tab bundle 40 can be flattened and measured.
[0070] In some embodiments, 3 mm ≤ L 2 ≤5mm. Set L 2 ≤5mm, which is beneficial to further reduce the space occupied by the second tab bundle 40 in the shell 10.
[0071] In some embodiments, Figure 4 As shown, the second tab bundle 40 is disposed on one side of the electrode assembly 20 along the second direction Y, and along the third direction Z, the width of the second tab bundle 40 is W.1 , 3mm≤W 1 ≤4mm. Set W 1 ≥3mm, the width of the second tab bundle 40 is not too small, which is beneficial to improve the current carrying capacity of the second tab bundle 40; setting W 1 ≤4 mm, the width of the second electrode tab bundle 40 is not too large, which is beneficial to reducing the influence of the second electrode tab bundle 40 on the width of the secondary battery 100 .
[0072] In some embodiments, Figure 4 As shown, along the extension direction of the first tab bundle 30, the length of the first tab bundle 30 is L 3 , 8mm≤L 3 ≤10mm. Set L 3 ≥8mm, the length of the first pole ear bundle 30 is not too short, and the length of the first pole ear 31 is not too short, which is conducive to reducing the difficulty of connecting the first pole ears 31; setting L 3 ≤10mm, the length of the first tab bundle 30 is not too long, which is beneficial to reduce the space occupied by the first tab bundle 30 in the housing 10, and is beneficial to improve the energy density of the secondary battery 100. The extension direction of the first tab bundle 30 corresponds to its length direction in the flattened state. When measuring the length of the first tab bundle 30, the first tab bundle 30 can be cut off from the first pole sheet 21, and then the first tab bundle 30 can be flattened and measured.
[0073] In some embodiments, Figure 4 As shown, the first tab bundle 30 is disposed on one side of the electrode assembly 20 along the second direction Y, and along the third direction Z, the width of the first tab bundle 30 is W. 2 , 3mm≤W 2 ≤4mm. Set W 2 ≥3mm, the width of the first tab bundle 30 is not too small, which is beneficial to improve the current carrying capacity of the first tab bundle 30; setting W 2 ≤4 mm, the width of the first electrode tab bundle 30 is not too large, which is beneficial to reducing the influence of the first electrode tab bundle 30 on the width of the secondary battery 100 .
[0074] In some embodiments, Figure 2 and Figure 5 As shown, the housing 10 includes a first protective layer 11, a metal layer 12 and a second protective layer 13, the metal layer 12 is sandwiched between the first protective layer 11 and the second protective layer 13, and the first protective layer 11 faces the inside of the housing 10. The secondary battery 100 includes a first adhesive 90, a plurality of second tabs 41 are welded to each other to form a first weld mark 40b, a plurality of first tabs 31 are welded to each other to form a second weld mark 30a, a first transfer tab 50 is welded to the first tab bundle 30 to form a third weld mark 50a, Figure 4The first weld mark 40b, the second weld mark 30a and the third weld mark 50a are indicated by dotted lines, and the first adhesive member 90 covers at least one of the first weld mark 40b, the second weld mark 30a or the third weld mark 50a. The first adhesive member 90 is provided to reduce the possibility of the first protective layer 11 being pierced by burrs generated during the welding process, thereby reducing the possibility of corrosion of the housing 10.
[0075] In some embodiments, Figure 5 As shown, the first adhesive member 90 includes a first adhesive portion 91 and a second adhesive portion 92, and the first adhesive portion 91 and the second adhesive portion 92 are arranged opposite to each other along the thickness direction of the first tab bundle 30 (in Figure 5 From the perspective, the first bonding portion 91 and the second bonding portion 92 overlap), the first bonding portion 91 bonds to the second bonding portion 92, and the first pole tab bundle 30, the second pole tab bundle 40 and the first transfer pole tab 50 located in the shell 10 are located between the first bonding portion 91 and the second bonding portion 92, so that the first bonding portion 91 and the second bonding portion 92 jointly cover the first weld mark 40b, the second weld mark 30a and the third weld mark 50a.
[0076] In some embodiments, the material of the first protective layer 11 includes, but is not limited to, polyethylene, polypropylene, polycarbonate, polyamide, polyethylene terephthalate, acrylonitrile-butadiene-styrene copolymer, polyoxymethylene, polyphenylene oxide, etc. By using the aforementioned materials, the first protective layer 11 is difficult to be dissolved or swelled by the electrolyte, which is beneficial to reduce the risk of corrosion of the metal layer 12.
[0077] In some embodiments, the material of the metal layer 12 includes but is not limited to aluminum foil, austenite-ferrite duplex stainless steel foil, etc. In this way, the metal layer 12 can react with oxygen to form a dense oxide film, thereby reducing the risk of moisture penetrating into the housing 10 .
[0078] In some embodiments, the material of the second protective layer 13 includes, but is not limited to, polyamide, polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, acrylonitrile-butadiene-styrene copolymer, polyoxymethylene, polyphenylene oxide, and the like.
[0079] In some embodiments, the second tab bundle 40 is accommodated in the housing and is not led out of the housing 10 .
[0080] The second tab bundle 40 is accommodated in the housing 10 , does not require an external adapter, and is not led out of the housing 10 , thereby improving the volume energy density and weight energy density of the secondary battery 100 .
[0081] In some embodiments, the length of the first tab bundle 30 along the extension direction of the first tab bundle 30 is L 3， Along the extension direction of the second tab bundle 40, the length of the second tab bundle 40 is L 2, L 2 , L 3 Meet L 2 <L 3 Since the second tab bundle 40 does not need to consider the transfer tab, the second tab bundle 40 can be made shorter, saving materials and space.
[0082] In some embodiments, Figure 6 and Figure 7 As shown, the secondary battery 100 further includes a third pole tab bundle 60, a fourth pole tab bundle 70 and a second adapter pole tab 80. The third pole tab bundle 60 is accommodated in the housing 10, and the third pole tab bundle 60 includes a plurality of third pole tabs 61, and the plurality of third pole tabs 61 are all connected to the second pole piece 22, and the ends of the plurality of third pole tabs 61 connected to the second pole piece 22 are arranged along the first direction X; the plurality of third pole tabs 61 are stacked. The fourth pole tab bundle 70 is accommodated in the housing 10, and the fourth pole tab bundle 70 includes a plurality of fourth pole tabs 71, and the plurality of fourth pole tabs 71 are all connected to the second pole piece 22, and the ends of the plurality of fourth pole tabs 71 connected to the second pole piece 22 are arranged along the first direction X, and the plurality of fourth pole tabs 71 are stacked. The second adapter pole tab 80 is connected to the third pole tab bundle 60, and a portion of the second adapter pole tab 80 extends out of the housing 10, and the second adapter pole tab 80 is connected to the housing 10. Since the second pole piece 22 is connected to the third pole piece bundle 60 and the fourth pole piece bundle 70, and only the third pole piece bundle 60 is connected to the second transfer pole piece 80, when the secondary battery 100 is impacted or dropped, even if a part of the third pole pieces 61 in the third pole piece bundle 60 are broken, the fourth pole piece bundle 70 can still play a conductive role. For the secondary battery 100 with a laminated structure, the fourth pole piece bundle 70 is conducive to connecting all the second pole pieces 22 to the circuit, which is conducive to the full release of the capacity of the secondary battery 100; for the secondary battery 100 with a wound structure, the fourth pole piece 71 is conducive to shortening the moving path of electrons, thereby helping to reduce the internal resistance of the secondary battery 100. In summary, the fourth pole piece bundle 70 is provided to maintain the performance of the secondary battery 100 when a part of the third pole pieces 61 are broken.
[0083] like Figure 8 As shown, the second aspect of the embodiment of the present application further provides an electric device 1000, and the electric device 1000 includes the secondary battery 100 involved in any of the above embodiments.
[0084] In some embodiments, the types of electrical devices 1000 include, but are not limited to, mobile phones, laptop computers, electronic cigarettes, power tools, and electric toys.
[0085] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present application and are not intended to be limiting of the present application. As long as they are within the spirit and scope of the present application, appropriate changes and modifications to the above embodiments are within the scope of the present application.
Claims
1. A secondary battery, characterized in that: include: case; An electrode assembly, comprising a first electrode piece, a second electrode piece and a separator, wherein the first electrode piece and the second electrode piece have opposite polarities, and the first electrode piece, the separator and the second electrode piece are stacked; the electrode assembly is accommodated in the housing; A first pole tab bundle is accommodated in the housing, the first pole tab bundle includes a plurality of first pole tabs, the plurality of first pole tabs are all connected to the first pole sheet, the plurality of first pole tabs are connected to the ends of the first pole sheet and are arranged along a first direction, the first direction being the thickness direction of the electrode assembly; the plurality of first pole tabs are stacked; A second pole tab bundle is accommodated in the housing, the length of the second pole tab bundle is shorter than the length of the first pole tab bundle, the second pole tab bundle includes a plurality of second pole tabs, the plurality of second pole tabs are all connected to the first pole piece, the plurality of second pole tabs are connected to the end of the first pole piece and are arranged along the first direction, and the plurality of second pole tabs are stacked; and The first transfer tab is connected to the first tab bundle and extends out of the shell, and the first transfer tab is connected to the shell.
2. The secondary battery according to claim 1, wherein: The second electrode tab bundle includes a first part and a second part, the second part connects the electrode assembly and the first part, and the first part and the second part are arranged at an angle; The first portion includes a first surface, the first surface faces the electrode assembly along a second direction, and the second direction is perpendicular to the first direction.
3. The secondary battery according to claim 2, characterized in that: The electrode assembly includes a second surface and a third surface that are opposite to each other along the first direction, and projections of the first electrode tab bundle and the second electrode tab bundle along the second direction are located between the second surface and the third surface.
4. The secondary battery according to claim 1 or 3, characterized in that: A plurality of the second electrode tabs are welded to each other to form a first weld mark. Along the extension direction of the second electrode tab bundle, the length of the first weld mark is L1, 2mm≤L1≤9mm.
5. The secondary battery according to claim 4, characterized in that: 3.8mm≤L1≤4.5mm.
6. The secondary battery according to claim 4, characterized in that: The first weld mark extends in a straight line.
7. The secondary battery according to claim 1, wherein: The first pole piece includes a first current collector, the first pole tab and the first current collector are an integrated structure, and the second pole tab and the first current collector are an integrated structure; The first pole tab bundle and the second pole tab bundle are arranged on the same side of the electrode assembly along the second direction, and the first pole tab bundle and the second pole tab bundle are arranged at intervals along the third direction; the first direction, the second direction and the third direction are perpendicular to each other; Along the third direction, a distance between the first electrode tab bundle and the second electrode tab bundle is D, and 2 mm ≤ D ≤ 3 mm.
8. The secondary battery according to claim 1, wherein: Along the extension direction of the second tab bundle, the length of the second tab bundle is L2, 3mm≤L2≤9mm; and / or The second electrode tab bundle is arranged on one side of the electrode assembly along the second direction. Along the third direction, the width of the second electrode tab bundle is W1, 3mm≤W1≤4mm; the first direction, the second direction and the third direction are perpendicular to each other.
9. The secondary battery according to claim 8, characterized in that Along the extending direction of the second pole tab bundle, the length of the second pole tab bundle is L2, and 3mm≤L2≤5mm.
10. The secondary battery according to claim 1, wherein: Along the extension direction of the first electrode tab bundle, the length of the first electrode tab bundle is L3, 8mm≤L3≤10mm; and / or The first electrode tab bundle is arranged on one side of the electrode assembly along the second direction. Along the third direction, the width of the first electrode tab bundle is W2, 3mm≤W2≤4mm; the first direction, the second direction and the third direction are perpendicular to each other.
11. The secondary battery according to claim 1, wherein The shell comprises a first protective layer, a metal layer and a second protective layer, the metal layer is sandwiched between the first protective layer and the second protective layer, and the first protective layer faces the interior of the shell; The secondary battery includes a first adhesive, a plurality of the second pole tabs are welded to each other to form a first weld mark, a plurality of the first pole tabs are welded to each other to form a second weld mark, the first transfer pole tab and the first pole tab bundle are welded to form a third weld mark, and the first adhesive covers at least one of the first weld mark, the second weld mark or the third weld mark.
12. The secondary battery according to claim 1, wherein: The secondary battery comprises: A third pole lug bundle is accommodated in the housing, the third pole lug bundle comprises a plurality of third pole lugs, the plurality of third pole lugs are all connected to the second pole piece, and ends of the plurality of third pole lugs connected to the second pole piece are arranged along the first direction; the plurality of third pole lugs are stacked; a fourth pole lug bundle, accommodated in the housing, the fourth pole lug bundle comprising a plurality of fourth pole lugs, the plurality of fourth pole lugs are all connected to the second pole piece, ends of the plurality of fourth pole lugs connected to the second pole piece are arranged along the first direction, and the plurality of fourth pole lugs are stacked; The second transfer tab is connected to the third tab bundle, a portion of the second transfer tab extends out of the shell, and the second transfer tab is connected to the shell.
13. The secondary battery according to claim 1, wherein: Along the extension direction of the first pole tab bundle, the length of the first pole tab bundle is L3, and along the extension direction of the second pole tab bundle, the length of the second pole tab bundle is L2, and L2 and L3 satisfy L2<L3.
14. The secondary battery according to claim 1, characterized in that: The second tab bundle is accommodated in the shell and is not led out of the shell.
15. An electrical equipment, characterized in that: Comprising the secondary battery according to any one of claims 1 to 14.