Single cell

Abstract

This invention provides a single-cell battery. The first current collector of the first electrode assembly includes a coated area coated with a first active material layer and an uncoated area not coated with the first active material layer but electrically connected to the electrode terminals. The direction pointing towards the coated area is a first direction. A connecting component is located on the side of the electrode assembly adjacent to the uncoated area along the first direction and is welded to the uncoated area to form a solder mark. The welding direction is opposite to the first direction. The uncoated area of ​​the first current collector has a first bending area and a second bending area sequentially arranged in the first direction. The first bending area and the second bending area have opposite bending directions in the radial direction of the electrode assembly. The projection of the first bending area in the first direction covers the separator on the first side of the first current collector, and the projection of the solder mark in the first direction covers the separator covered by the first bending area. This technical solution at least avoids the problem of the separator being easily burned by welding heat.

Description

Technical Field

[0001] This utility model relates to the field of secondary battery technology, and more specifically, to a single-cell battery. Background Technology

[0002] In the field of new energy power batteries, secondary batteries refer to rechargeable batteries, also known as renewable batteries or accumulators. Unlike primary batteries, secondary batteries can undergo multiple charge-discharge cycles through reverse charging for reuse. A secondary battery generally includes electrode assemblies and a casing. The electrode assembly consists of a second electrode, a first electrode, and a separator located between the second and first electrodes. These second electrodes, first electrodes, and separator are stacked and wound to form the electrode assembly, which is then encapsulated within the casing. However, existing secondary batteries suffer from the problem of susceptibility to separator damage, such as being easily burned during welding. Utility Model Content

[0003] In view of the problems existing in the related technologies, the purpose of this utility model is to provide a single cell battery that can at least avoid the problem of the separator being easily burned by the welding heat.

[0004] To achieve the above objectives, this utility model provides a single-cell battery, comprising: a casing with electrode terminals; an electrode assembly housed within the casing, including a first electrode, a second electrode, and a separator disposed between the first and second electrodes, the first electrode including a first current collector and a first active material layer, the first current collector including a coated area coated with the first active material layer and an uncoated area not coated with the first active material layer, the uncoated area being electrically connected to the electrode terminals, and the direction from the coated area to the uncoated area being a first direction; and a connecting component located on the side of the electrode assembly adjacent to the uncoated area along the first direction. The adapter component is welded to the uncoated area to form a solder mark. The welding direction of the adapter component to the uncoated area is in the opposite direction to the first direction. The uncoated area of ​​the first current collector has a first bending area and a second bending area arranged sequentially in the first direction. The first bending area and the second bending area have opposite bending directions in the radial direction of the electrode assembly. The projection of the first bending area in the first direction covers the diaphragm on the first side of the first current collector. The first side is the side to which the bending direction of the first bending area points. The projection of the solder mark in the first direction covers the diaphragm covered by the first bending area.

[0005] In some embodiments, the adapter is a collector plate located on one side of the electrode assembly along a first direction and welded to the uncoated area to electrically connect the uncoated area to the electrode terminal; wherein the first bending area and the second bending area are connected by a first straight section, and the first straight section is welded to the collector plate.

[0006] In some embodiments, the adapter is a manifold located on one side of the electrode assembly along a first direction and welded to the uncoated area to electrically connect the uncoated area to the electrode terminal; wherein the first bending area and the second bending area are connected by a first straight section, and the solder mark between the manifold and the uncoated area is spaced apart from the first straight section.

[0007] In some embodiments, the uncoated area further includes a straight connecting segment connected to the end of the second bend area away from the coated area, and the straight connecting segments of the multiple uncoated areas are stacked in a first direction and welded to the manifold.

[0008] In some embodiments, the first bending area includes a rounded corner, a first straight section and a second straight section. The first straight section connects to the end of the rounded corner away from the coating area, and the second straight section connects to the end of the rounded corner adjacent to the coating area. The minimum distance between the first straight section and the second straight section in the first direction is a, where a ≥ 2b, and b is the thickness of the first current collector.

[0009] In some embodiments, the first bending region contacts the diaphragm located on the first side of the first current collector, and the diaphragm is pressed down to bend the diaphragm.

[0010] In some embodiments, the projection of the first bending region fully covers the diaphragm that contacts the first bending region.

[0011] In some embodiments, the diaphragm has a segment extending beyond the first active material layer in a first direction, the extension distance of the segment beyond the first active material layer being 0.5 mm to 3 mm.

[0012] In some embodiments, the second electrode includes a second current collector and a second active material layer covering a portion of the surface of the second current collector, wherein, in a first direction, the height of the first active material layer extending beyond the second current collector is greater than 1 mm.

[0013] In some embodiments, the second current collector includes a coated area coated with a second active material layer and an uncoated area not coated with the second active material layer. The coated area and the uncoated area of ​​the second current collector are arranged adjacent to each other in the opposite direction to the first direction. The housing is further provided with another electrode terminal, and the uncoated area of ​​the second current collector is electrically connected to the other electrode terminal.

[0014] In some embodiments, the end of the first bending region in its bending direction is inserted into a radially adjacent first bending region.

[0015] In some embodiments, the single cell further includes a tail insulating tape for fixing the tail end of the separator; wherein the electrode assembly includes a body, the body including a coating area of ​​a first active material layer and a first current collector, and there are multiple uncoated areas and any second bending area is located within the projection range of the body and the tail insulating tape in a first direction.

[0016] In some embodiments, along the first direction, the uncoated area is further provided with another first bending region on the side of the second bending region away from the first active material layer.

[0017] In some embodiments, the housing includes an end wall and a side wall connected to the edge of the end wall. One end of the side wall has an opening in a first direction. A groove protruding radially inward along the opening is provided on the side wall adjacent to the opening. The electrode assembly is located between the end wall and the groove. The adapter is a collector plate, which is connected to the side of the groove facing the electrode assembly.

[0018] In some embodiments, the sidewall of the housing has an opening at one end along a first direction, and the housing further includes a cover plate assembly that covers the opening. The adapter is the cover plate assembly, the uncoated area is welded to the cover plate assembly, and the cover plate assembly is electrically connected to the electrode terminals. The first bending area and the second bending area are connected by a first straight section. The first straight section is welded to the cover plate assembly, or the weld mark between the cover plate assembly and the uncoated area is spaced apart from the first straight section.

[0019] In some embodiments, in the first direction, the distance between the first bending region and the first active material layer is d, where 0.5mm≤d≤2.5mm.

[0020] In some embodiments, the uncoated area is electrically connected to the electrode terminals via a manifold or cover plate assembly, wherein the uncoated area further includes a straight connecting segment connected to the end of the second bent area away from the coated area, the straight connecting segment being stacked in a first direction and welded to the manifold or cover plate assembly.

[0021] In some embodiments, the electrode terminal is a housing, or the electrode terminal is a post connected to the housing.

[0022] Embodiments of this application also provide a battery pack, including any of the individual cells described above.

[0023] Embodiments of this application also provide an electronic device including the battery pack described above.

[0024] The beneficial technical effects of this invention include: by providing a first bending area and a second bending area on the uncoated area of ​​the first current collector used as the electrode tab, the number of layers of the uncoated area above the diaphragm is increased, which can more effectively protect the diaphragm. For example, by increasing the number of layers of the uncoated area above the diaphragm, the number of weldable layers of the electrode tab is increased, the welding process window is increased, and the diaphragm can be prevented from being burned by welding heat. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A schematic diagram is shown when the electronic device according to an embodiment of this application is a vehicle.

[0027] Figure 2A A perspective view of a secondary battery according to an embodiment of this application is shown.

[0028] Figure 2B A cross-sectional view of a secondary battery according to an embodiment of this application is shown.

[0029] Figure 3A A cross-sectional view of the existing electrode assembly is shown.

[0030] Figure 3B This is a partially enlarged schematic diagram of the cross-section of an existing electrode assembly.

[0031] Figure 4A This is a planar schematic diagram of a first electrode according to an embodiment of this application.

[0032] Figure 4B This is a perspective view of an electrode assembly according to an embodiment of this application.

[0033] Figure 5 This is a cross-sectional view of another existing electrode assembly.

[0034] Figure 6A This is a cross-sectional schematic diagram of an electrode assembly according to some embodiments.

[0035] Figure 6B yes Figure 6A A partially enlarged schematic diagram of the electrode assembly shown.

[0036] Figure 6C yes Figure 6A The diagram shows a partially enlarged view of the electrode assembly being welded to the first collector plate.

[0037] Figure 7A A partially enlarged schematic diagram of an electrode assembly on one side of the first collector plate, according to some embodiments, is shown.

[0038] Figure 7B A top view of the first collector disk in this embodiment is shown.

[0039] Figure 8 This is a cross-sectional schematic diagram of an electrode assembly according to another embodiment.

[0040] Figure 9 This is a cross-sectional schematic diagram of an electrode assembly according to another embodiment. Detailed Implementation

[0041] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.

[0042] Embodiments of this application will be described in detail below. Throughout this specification, identical or similar components and components having identical or similar functions are indicated by similar reference numerals. The embodiments described herein with reference to the accompanying drawings are illustrative and diagrammatic in nature and are intended to provide a basic understanding of this application. The embodiments of this application should not be construed as limiting this application.

[0043] As used herein, the terms “approximately,” “generally,” “substantially,” and “about” are used to describe and indicate minor variations. When used in conjunction with an event or situation, these terms may refer to examples in which the event or situation occurred precisely or in examples in which the event or situation occurred very approximately.

[0044] In this specification, unless otherwise specified or limited, relative terms such as “central,” “longitudinal,” “lateral,” “front,” “rear,” “right,” “left,” “inner,” “outer,” “lower,” “higher,” “horizontal,” “vertical,” “above,” “below,” “above,” “below,” “top,” “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to the directions described in the discussion or depicted in the accompanying drawings. These relative terms are used for descriptive convenience only and do not require that this application be constructed or operated in a particular orientation.

[0045] For ease of description, the terms "first," "second," "third," etc., are used herein to distinguish different components of a figure or a series of figures. "First," "second," "third," etc., are not intended to describe corresponding components. Furthermore, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0046] This application provides an electronic device 1000. For ease of explanation, the following embodiments use a vehicle as an example to illustrate the electronic device 1000. See also... Figure 1The vehicle has a battery pack 1002 installed inside, which can be located at the bottom, front, or rear of the vehicle body 1001. The battery pack 1002 can be used to power the vehicle; for example, it can serve as the vehicle's operating power source. The working part of the electronic device 1000 is electrically connected to the battery pack 1002 to obtain electrical power. The vehicle can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, but are not limited thereto. The working part is the vehicle body, and the battery pack 1002 is located at the bottom of the vehicle body, providing electrical power for the vehicle's movement or the operation of its internal electrical components. However, in some other embodiments, the electronic device 1000 can also be a mobile phone, portable device, laptop, ship, spacecraft, electric toy, and power tool, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; the working part can obtain electrical energy from the battery pack 1002 and perform corresponding functions, such as a fan blade rotation unit or a vacuum cleaner's suction unit. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the aforementioned electronic device 1000.

[0047] Figure 2A A perspective view of a secondary battery 100 according to an embodiment of this application is shown. Figure 2B A cross-sectional view of a secondary battery 100 according to an embodiment of this application is shown. The secondary battery 100 may also be referred to as a single-cell battery. See also... Figure 2A and Figure 2BAs shown, in an embodiment where the secondary battery 100 is a cylindrical battery, the secondary battery 100 includes a housing 200 and an electrode assembly 120 installed within the housing 200. The secondary battery 100 has a height direction h. Along the opposite direction of height h, one end of the housing 200 has an opening, and a cover assembly 220 is used to seal the opening. The housing 200 and the cover assembly 220 are components that jointly house the electrode assembly 120 and the electrolyte. The housing 200 can be made of any of a variety of available materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The housing 200 can be cylindrical and define a receiving cavity in which the electrode assembly 120 is disposed. The diameter of the housing 200 can be determined according to the specific diameter of the electrode assembly 120, such as 18mm, 21mm, 46mm, etc. In some embodiments, the secondary battery 100 may be a 4680 cylindrical battery (46mm in diameter and 80mm in height), or a 4695 cylindrical battery (46mm in diameter and 95mm in height), or a 46120 cylindrical battery (46mm in diameter and 120mm in height).

[0048] The housing 200 may include an end wall 111 and a side wall 112 surrounding the end wall 111. The side wall 112 is connected to the edge of the end wall 111. The end wall 111 and the side wall 112 may together define a receiving cavity to receive the electrode assembly 120 of the secondary battery 100. After the electrode assembly 120 is placed into the housing 200, the opening of the housing 200 may be closed by a cover assembly 220.

[0049] A groove 113 protruding radially inward along the opening is provided on the sidewall 112 adjacent to the opening. Along the height direction h of the secondary battery 100, the electrode assembly 120 is disposed between the end wall 111 of the housing 200 and the groove 113, the groove 113 restricting the axial movement of the electrode assembly 120 between the end wall 111 and the groove 113. The end of the sidewall 112 of the housing 200 on the opening side can be configured as a rolled edge portion 11432, extending radially inward into the housing along the opening. The rolled edge portion 11432 and the groove 113 are spaced apart along the height direction h, and the groove 113 and the rolled edge portion 11432 can jointly clamp the cover assembly 220. The cover assembly 220 can be electrically insulated from the housing 200. For example, the cover assembly 220 and the housing 200 can be electrically insulated by providing an insulating member between the edge of the cover assembly 220 and the sidewall 112.

[0050] The cover assembly 220 may have a weak point. When the battery experiences thermal runaway, the high-temperature and high-pressure emissions inside can be discharged to the outside by breaking through the weak point on the cover assembly 220 from the bottom of the battery, thereby achieving good discharge of the emissions.

[0051] In some embodiments, the end wall 111 of the housing 200 can serve as a first electrode terminal (e.g., a negative terminal) of the secondary battery. In some embodiments, the first tab (e.g., a negative tab) of the electrode assembly 120 faces the cover assembly 220, and the first tab can be electrically connected to the housing 200 via a first current collector 201 located between the cover assembly 220 and the electrode assembly 120, thereby energizing the housing 200 (e.g., making it negatively charged). In this embodiment, the first current collector 201 can be referred to as a transition component for the electrical connection between the electrode assembly 120 and the negative terminal. The first current collector 201 can be welded to the side wall 112 of the housing 200 by laser welding. Furthermore, the first current collector 201 is also welded to the first tab. In one embodiment, the welding position of the first current collector 201 to the side wall 112 is located on the side of the groove 113 facing the electrode assembly 120. In other embodiments, the first tab can be directly welded to the cover assembly 220, thereby energizing the housing 200 (e.g., making it negatively charged). In this embodiment, the cover plate assembly 220 can be referred to as a transition component for electrically connecting the electrode assembly 120 to the negative terminal.

[0052] The secondary battery 100 may further include a terminal post 80 that passes through and is insulated from the end wall 111. The terminal post 80 can serve as a second electrode terminal (e.g., a positive terminal) of the secondary battery. The terminal post 80 can be electrically connected to a second tab (e.g., a positive tab) of the electrode assembly 120 via a second current collector 202 located between the terminal post 80 and the electrode assembly 120, thereby making the terminal post 80 charged (e.g., positively charged). The second current collector 202 can be referred to as a transition component for the electrical connection between the electrode assembly 120 and the positive terminal. In some embodiments, the terminal post 80 can be welded to the second current collector 202 via laser penetration welding, and the second current collector 202 can be welded to the second tab.

[0053] The electrode assembly 120 can be mainly formed by sequentially stacking and winding a positive electrode, a negative electrode, and a separator located between the positive and negative electrode. The positive electrode, negative electrode, and separator can be wound around an axis. Furthermore, the electrode assembly 120 can have a winding center hole 120c, and the winding axis can be the axis of the winding center hole 120c.

[0054] In some embodiments, the positive electrode sheet may include a positive current collector and a positive active material layer, the positive active material layer being coated on a portion of the surface of the positive current collector. Uncoated areas of the positive current collector not covered by the positive electrode coating area are used to form positive electrode tabs. The negative electrode sheet may include a negative current collector and a negative active material layer, the negative active material layer being coated on a portion of the surface of the negative current collector. Uncoated areas of the negative current collector not covered by the negative electrode coating area are used to form negative electrode tabs.

[0055] In one example of the secondary battery 100 of the present invention, the method for manufacturing the secondary battery 100 of the present invention includes the following steps:

[0056] Winding: A winding structure is formed by stacking and winding negative electrode sheets (such as the first electrode sheet), diaphragm, and positive electrode sheets (such as the second electrode sheet). The uncoated portions of the negative current collector of the negative electrode sheet and the positive current collector of the positive electrode sheet are used as positive electrode tabs and negative electrode tabs, and the positive electrode tabs and negative electrode tabs are bent radially toward the winding center hole of the electrode assembly.

[0057] Welding of the current collector to the electrode assembly: The second current collector 202 and the first current collector 201 are welded to the surface areas of the bent positive electrode tab and negative electrode tab, respectively.

[0058] Installation into the housing: The electrode assembly 120, which has been welded to the first collector plate 201 and the second collector plate 202, is installed into the housing 200 through the opening. The method of installing the electrode assembly 120 in this step is not limited. For example, it can be installed manually or by a robot.

[0059] Install pole 80.

[0060] Inject electrolyte.

[0061] Sealing: The cover assembly 220 is sealed and installed over the opening. Various sealing methods exist, and none are limited to one. In some embodiments, a rolling groove 113 recessed towards the center of the housing 200 is first formed on the outer periphery of the housing 200 to restrict the movement of the electrode assembly 120 along the height direction h. Then, a mechanical sealing process is used to press and seal the cover assembly 220 to form a rolled edge 11432, thereby sealing the cover assembly 220 over the opening of the housing 200. This step is a mature, low-cost, and highly efficient process.

[0062] Figure 3A A cross-sectional view of the existing electrode assembly 120 is shown. Figure 3B This is a partially enlarged schematic diagram of the cross-section of the existing electrode assembly 120. See also... Figure 3A and Figure 3B As shown, the electrode assembly 120 includes a first electrode 10, a second electrode 20, and a diaphragm 122 disposed between the first electrode 10 and the second electrode 20.

[0063] The first electrode 10 may include a first current collector 18 and a first active material layer 16, wherein a portion of the opposing surfaces of the first current collector 18 along its thickness direction is covered by the first active material layer 16. The first current collector 18 includes a coated area 18b coated with the first active material layer 16 and an uncoated area 18a not covered by the first active material layer 16. The coated area 18b and the uncoated area 18a are adjacent to each other in the opposite direction of the height direction h. The uncoated area 18a can be used as a first electrode tab, such as a negative electrode tab. The second electrode 20 includes a second current collector 28 and a second active material layer 26, wherein at least a portion of the surfaces of the second current collector 28 along both sides of its thickness direction are covered by the second active material layer 26. The second current collector 28 includes a coated area 28b coated with the second active material layer 26 and an uncoated area 28a not covered by the second active material layer 26. The coated area 28b and the uncoated area 28a are adjacent to each other in the height direction h. The uncoated area 28a can be used as a second electrode tab, such as a positive electrode tab. In this embodiment, the electrode assembly 120 has a positive electrode tab and a negative electrode tab on opposite sides.

[0064] In some embodiments, the first electrode 10 is a negative electrode, and the second electrode 20 is a positive electrode. In such embodiments, for example, taking a lithium-ion battery, the first current collector 18 can be made of copper, and the first active material layer 16 can include a first active material (negative electrode active material), which can be carbon or silicon, etc. The second current collector 28 can be made of aluminum, and the second active material layer 26 can include a second active material (positive electrode active material), which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. In some embodiments, the separator 122 can be made of, for example, PP (polypropylene) or PE (polyethylene), etc.

[0065] To minimize the possibility of contact between the first electrode 10 and the second electrode 20, the electrode assembly 120 may further include an insulating layer 40 that covers at least a portion of the uncoated area 28a of the second current collector 28. The insulating layer 40 may be provided on both sides of the second current collector 28. The insulating layer 40 effectively prevents electrical contact between the first electrode 10 and the second electrode 20.

[0066] In some embodiments, the insulating layer 40 is mainly composed of boehmite and PVDF (polyvinylidene difluoride). Boehmite accounts for 80% and PVDF accounts for 20%. In some embodiments, the insulating layer 40 is a ceramic material layer. In some embodiments, the insulating layer 40 includes a color developer to distinguish whether the side coated with the insulating layer 40 is the front or back of the second electrode 20, including but not limited to distinguishing the areal density of the front and back of the second electrode 20. The main component of the color developer can be bismuth vanadate, which is yellow in color.

[0067] The uncoated areas 18a and 28a of the first current collector 18 and the second current collector 28 can be bent toward the winding center hole 120c of the electrode assembly 120, respectively. Multiple bent uncoated areas 18a extending from the first current collector 18 are stacked on top of each other, and multiple bent uncoated areas 28a extending from the second current collector 28 are stacked on top of each other. The electrode assembly 120 has tabs on opposite sides, with the first current collector 201 and the second current collector 202 (see...). Figure 2B The first current collector 201 can be connected to the uncoated areas 18a stacked on top of each other, and the second current collector 202 can be connected to the uncoated areas 28a stacked on top of each other. The first current collector 201 can be connected to the uncoated areas 18a stacked on top of each other, for example by welding, and further electrically connected to the housing 200. The second current collector 202 can be connected to the uncoated areas 28a stacked on top of each other, for example by welding, and further electrically connected to the electrode post 80.

[0068] The following description uses the first electrode 10 as the negative electrode and the second electrode 20 as the positive electrode. However, it should be understood that in other embodiments, the first electrode 10 can be the positive electrode, and the first tab of the first electrode 10 can be electrically connected to the terminal 80.

[0069] In some embodiments, the first tab (uncoated area 18a) is designed with a slit-and-stack configuration. Specifically, a first active material layer 16 is coated on the opposing two surfaces of the first current collector 18 along its thickness direction. The first active material layer 16 can be coated onto the first current collector 18 using a coating device. The edge portion of the first current collector 18 in the width direction W1 (corresponding to the opposite direction of the aforementioned height direction h) is a blank area where the first active material layer 16 is not coated. Please refer to [reference needed]. Figure 4A The blank area is cut to form multiple first tabs (uncoated area 18a).

[0070] After forming the first electrode 10 and the second electrode 20, the first electrode 10, the diaphragm, and the second electrode 20 can be stacked and wound together to form a wound electrode assembly. After winding, please refer to... Figure 4BThe uncoated area 18a of the first electrode 10 can be bent to form a first bent area 51 and a second bent area 52, and bent toward the winding center hole 120c and stacked on top of each other. The uncoated area 28a of the second electrode 20 can be formed in the same way as the uncoated area 18a, and then bent toward the winding center hole and stacked on top of each other. The uncoated areas 18a and 28a of this structure can be called a cut-and-stack design.

[0071] Furthermore, at the head a1 of the first current collector 18 ( Figure 4A The uncoated area 18a is not provided to avoid obscuring the winding center hole 120c of the wound electrode assembly 120; and / or, at the tail a3 of the first current collector 18 Figure 4A Similarly, no uncoated area 18a is provided to avoid the projection range of the second bending area 52 of the uncoated area 18a in the height direction h exceeding the electrode assembly 120, so as not to affect the diameter of the electrode assembly 120 and facilitate the insertion of the electrode assembly 120 into the housing.

[0072] Figure 5 This is a cross-sectional view of another existing electrode assembly 120. Figure 5 Several aspects of the electrode assembly shown can be compared with the above references. Figure 3A and Figure 3B The description is the same. Figure 5 The difference in the electrode assembly shown is that the uncoated area 18a of the first current collector 18 is provided with a bent area 50 that bends away from the winding center hole 120c.

[0073] exist Figure 3A and Figure 5 In the electrode assembly 120 shown, there is a problem that the separator is easily damaged. For example, in the tab design of a large cylindrical single cell, the first tab (uncoated area 18a) usually adopts the above-mentioned folded design, which facilitates the welding of the tab to the current collector or cover plate assembly after bending. However, the separator is easily burned during the welding process, which can cause the separator to shrink due to heat and cause a short circuit between the positive and negative electrodes inside the battery.

[0074] Figure 6A This is a cross-sectional schematic diagram of an electrode assembly according to some embodiments. Figure 6B yes Figure 6A A partially enlarged schematic diagram of the electrode assembly shown. See also... Figure 6A and Figure 6BAs shown, the direction from the coated area 18b to the uncoated area 18a is direction D1 (also referred to as the first direction). Direction D1 can correspond to the opposite direction of the aforementioned height direction h. The uncoated area 18a of the first current collector 18 has a first bending area 51 and a second bending area 52 arranged sequentially in direction D1. The first bending area 51 and the second bending area 52 have opposite bending directions in the radial direction of the electrode assembly 120. In this embodiment, the first bending area 51 bends toward the winding center hole 120c, and the second bending area 52 bends away from the winding center hole 120c.

[0075] The projection of the first bending region 51 in direction D1 can cover the diaphragm 122 of the first side S1 of the first current collector 18, where the first side S1 is the side to which the bending direction of the first bending region 51 points. In this embodiment, the first side S1 is the side of the first current collector 18 facing the winding center hole 120c, and the projection of the first bending region 51 covers the diaphragm 122 of the first current collector 18 facing the winding center hole 120c.

[0076] Figure 6C yes Figure 6A A partially enlarged schematic diagram showing the electrode assembly welded to the first current collector 201. See also... Figure 6C The first current collector 201 is welded to the uncoated area 18a of the first current collector 18 to form a solder mark 205. The projection of the solder mark 205 in direction D1 covers the diaphragm 122 covered by the first bending area 51. Thus, the first bending area 51 is disposed between the solder mark 205 and the diaphragm 122 along direction D1. The welding direction of the first current collector 201 and the uncoated area 18a is in the opposite direction of direction D1, that is, from the first current collector 201 toward the electrode assembly 120. Since the thickness of the transition component (current collector or cover plate assembly) is usually much greater than the thickness of a single layer of uncoated area, even if the electrode tab adopts a stacked design, the number of stacked uncoated areas is usually limited and the superimposed thickness is still less than that of the transition component. Since welding requires melting the transition component and the uncoated area to form a solder mark, a high welding heat is required during the welding process, and the heat of the welding process is transferred from the diaphragm 122 facing below the solder mark 205.

[0077] exist Figures 6A to 6CIn the illustrated embodiment, by providing a first bending region 51 and a second bending region 52 on the uncoated area 18a of the first current collector 18, which serves as the first tab, the number of layers of the uncoated area 18a above the diaphragm 122 is increased. The increased number of uncoated area layers 18a can block the conduction of welding heat towards the diaphragm 122 below the solder mark 205, reducing the heat reaching the diaphragm 122 and lowering the temperature at the diaphragm 122 during welding. This provides more effective protection for the diaphragm, preventing it from being burned by welding heat. Furthermore, by increasing the number of uncoated area layers 18a above the diaphragm 122, the number of weldable layers between the uncoated area 18a and the first current collector 201 is increased, expanding the welding process window and also preventing the diaphragm 122 from being burned by welding heat. Furthermore, in a stacked cylindrical battery, especially when the number of layers stacked in the first direction of multiple radially adjacent uncoated areas 18a is limited, the number of layers of uncoated areas 18a above the separator 122 is further increased by providing a first bending area 51 and a second bending area 52 on each uncoated area 18a below the stacked area, thereby reducing the heat reaching the separator 122.

[0078] Specifically, the first bending area 51 may include a rounded corner 511, a first straight section 512, and a second straight section 513. The first straight section 512 is connected to the end of the rounded corner 511 away from the coating area 18b, and the second straight section 513 is connected to the end of the rounded corner 511 adjacent to the coating area 18b. The minimum distance between the first straight section 512 and the second straight section 513 in direction D1 is a, where b is the thickness of the first current collector 18, satisfying a ≥ 2b. When the minimum distance a between the first straight section 512 and the second straight section 513 is set to ≥ 2b, the gap between the first straight section 512 and the second straight section 513 can be effectively used for heat insulation, reducing the possibility of thermal shrinkage of the diaphragm 122 and preventing welding heat from being directly transferred to the diaphragm 122 and burning it. In some embodiments, the projections of adjacent first bending regions 51 in direction D1 do not overlap in the radial direction of the electrode assembly; that is, the first bending region 51 does not insert into the adjacent first bending region 51. In other embodiments, the first bending region 51 may insert into the adjacent first bending region 51, but a gap is left between them to use the gap for heat insulation, preventing welding heat from being conducted toward the diaphragm 122 below the solder stamp 205, thus avoiding the diaphragm 122 being burned by welding heat.

[0079] It should be noted that the straightness (e.g., the first straight section) involved in this application is not limited to horizontal straightness, but refers to the part of the uncoated area 18a where no bending occurs.

[0080] In some embodiments, the second bending region 52 is a rounded corner 521. The uncoated region 18a may also include a straight connecting segment 531, which is connected to the end of the second bending region 52 away from the coated region 18b. The straight connecting segments 531 of a plurality of uncoated regions 18a may be stacked in direction D1. The rounded corner 511 of the first bending region 51 is connected to the second bending region 52 by a first straight segment 512.

[0081] In some embodiments, the first collector plate 201 is located on one side of the electrode assembly 120 along direction D1, and the uncoated area 18a is welded to the first collector plate 201. Figure 7A A partially enlarged schematic diagram of the electrode assembly 120 on one side of the first collector plate 201 in this embodiment is shown. Figure 7B A schematic diagram of the structure of the first collector disk 201 in this embodiment is shown.

[0082] Combination Figure 7A and Figure 7B As shown, the first current collector 201 may include a body portion 30 and at least one tab connection portion 31. The tab connection portion 31 is disposed on the body portion 30 and is electrically connected to the body portion 30. The number and structural form of the tab connection portions 31 are not limited, as long as they can form a stable electrical connection with the first tab. In some embodiments, a perforated structure 39 may be provided around the tab connection portion 31, and the perforated structure 39 is partially surrounded on the outer periphery of the tab connection portion 31. The end of the outer periphery of the tab connection portion 31 without the perforated structure 39 is electrically connected to the body portion 30, and the portion of the outer periphery of the tab connection portion 31 with the perforated structure 39 is separated from the body portion 30 by the perforated structure 39. The specific shape of the perforated structure 39 is not limited, for example, it may be an open circular ring structure, an open square ring structure, etc., as long as it can meet the conductive connection requirements of the tab connection portion 31.

[0083] In some embodiments, a bend 34 is provided at the connection position between the tab connecting portion 31 and the body portion 30. One end of the bend 34 can be integrally formed and connected to the tab connecting portion 31, and the other end of the bend 34 can be integrally formed and connected to the body portion 30. The shape of the bend 34 can be selected in various ways, as long as it can ensure the parallelism between the surface of the tab connecting portion 31 and the surface of the body portion 30. By providing the bend 34 at the connection position between the body portion 30 and the tab connecting portion 31, the bend 34 can buffer stress and improve the stability of the welded connection between the tab connecting portion 31 and the first tab.

[0084] At least one housing connection portion 32 may be provided on the body portion 30 of the first collector plate 201. The number of housing connection portions 32 can match the number of electrode connection portions 31, and the housing connection portions 32 are located on the circumferential outer side of the electrode connection portions 31. One end of the housing connection portion 32 is electrically connected to the body portion 30, and the other end of the housing connection portion 32 is fixedly electrically connected to the side wall 112 of the housing 200. The fixed electrical connection includes, but is not limited to, welding connection. The structural shape of the housing connection portion 32 is not limited, as long as it can meet the connection strength and current conduction requirements with the side wall 112. Specifically, the housing connection portion 32 may be located on the side of the groove 113 facing the electrode assembly 120, and welded and fixed to the side of the groove 113 facing the electrode assembly 120.

[0085] In some embodiments, the groove 113 is formed by the following steps: the housing connection portion 32 is connected to the side wall 112 of the housing 200; then a grooving process is performed to deform the side wall 112 to form the groove 113, and the housing connection portion 32 is connected to the side of the groove 113 facing the electrode assembly 120. Because a large deformation stress is generated on the housing connection portion 32 during the deformation of the groove 113, this stress is transmitted to the coating area 18b of the first current collector 18, causing the first active material layer 16 to detach. The first bending area 51 can provide a buffer in this grooving process, preventing the pressure in the grooving process from being transmitted to the coating area 18b of the first current collector 18, causing the first active material layer 16 to detach.

[0086] Specifically, and then combined Figure 6A and Figure 6B As shown, the straight connecting segments 531 of the multilayer uncoated area 18a are stacked in direction D1 and welded to the first current collector 201. Furthermore, the first straight segment 512 below the straight connecting segment 531 can also be welded to the first current collector 201. That is, both the straight connecting segment 531 and the first straight segment 512 can be used to weld to the first current collector 201, thus increasing the number of weldable layers in the uncoated area 18a. In this embodiment, the uncoated area 18a can be provided on the outer ring of the electrode assembly. Compared to the prior art, the number of stacked layers of the outer ring tabs is less. This application, by increasing the number of weldable layers in the uncoated area 18a, avoids the separator 122 being burned by welding heat. Furthermore, after adding the first bending area 51, the uncoated area 18a of the outer ring can also be welded to the first current collector 201, increasing the welding area between the first current collector and the tabs and reducing the battery's internal resistance.

[0087] In other embodiments, the straight connecting segment 531 may be welded to the first collector plate 201, and the first straight segment 512 may not be welded to the first collector plate 201. Thus, the straight connecting segment 531 of the uncoated area 18a is welded to the first collector plate 201 to form a solder mark (e.g., Figure 6CThe solder mark 205 in the uncoated area 18a is spaced apart from the first straight section 512. In such an embodiment, the uncoated area 18a can be set in the inner ring of the electrode assembly to be welded to the middle area of ​​the first collector plate 201. In this way, the number of stacked uncoated areas 18a will be large. By spaced apart the first straight section 512 and the solder mark of the uncoated area 18a to the first collector plate 201, heat can be blocked, preventing the welding heat from being conducted to the diaphragm 122, reducing the risk of diaphragm 122 being burned or shrinking due to heat.

[0088] In other embodiments, the uncoated area 18a can be directly welded to the cover plate assembly 220, i.e., the first collector plate 201 may not be provided. Specifically, the straight connecting segment 531 is stacked in direction D1 and directly welded to the cover plate assembly 220. In some embodiments, the first straight segment 512 may also be welded to the cover plate assembly 220. In other embodiments, the straight connecting segment 531 is welded to the cover plate assembly 220, and the first straight segment 512 may not be welded to the cover plate assembly 220, wherein the weld marks between the cover plate assembly 220 and the straight connecting segment 531 are spaced apart from the first straight segment 512.

[0089] The separator 122 has a segment 122s extending beyond the first active material layer 16 in direction D1, with the extension distance of segment 122s beyond the first active material layer 16 being 0.5mm-3mm. That is, before the separator between the positive and negative electrode plates is sequentially stacked and wound, segment 122s extends in direction D1, and the extension distance of segment 122s is the height of segment 122s in direction D1. If the extension distance of segment 122s is greater than 3mm, the separator 122 is too long, resulting in waste, and it is also easy for the separator 122, which is bent by the first bending region 51, to extend beyond the first bending region 51, making it prone to thermal shrinkage. If the extension distance of segment 122s is less than 0.5mm, assembly errors may cause the separator 122 to fail to provide effective insulation, leading to a short circuit.

[0090] In some embodiments, in direction D1, the first active material layer 16 extends beyond the second current collector 28 by a height H1, where H1 is greater than 1 mm. Since the first active material layer 16 can be used to provide support for the uncoated area 18a, H1 being greater than 1 mm ensures that the height of the second current collector 28 is not higher than the first active material layer 16, guaranteeing a gap between the first bending area 51 and the second current collector 28, and a gap between the first bending area 51 and the second current collector 28 and the second active material layer 26, thus avoiding short overlaps.

[0091] In direction D1, the distance between the first bending region 51 and the first active material layer 16 is d, where 0.5mm ≤ d ≤ 2.5mm. In an embodiment with two first bending regions 51, d is the distance between the first bending region 51 closest to the first active material layer 16 and the first active material layer 16. If d is too small, the first active material layer 16 may detach due to stress caused by its proximity to the first bending region 51. If d is too large, it will waste the height space of the battery.

[0092] The secondary battery can also have a termination insulating strip on the periphery of the electrode assembly to fix the termination end of the separator 122. The main body of the electrode assembly 120 may include a first active material layer and a coating area of ​​the first current collector 18. Any second bending area 52 (i.e., including the outermost second bending area 52) is located within the projection range of the main body of the electrode assembly 120 and the termination insulating strip in direction D1. That is, the outermost edge of the outwardly bent second bending area 52 does not exceed the outermost edge of the electrode assembly (including the termination insulating strip), so as not to affect the diameter of the electrode assembly and to facilitate the insertion of the electrode assembly into the casing.

[0093] Figure 8 This is a cross-sectional schematic diagram of an electrode assembly according to another embodiment. Figure 8 Several aspects of the illustrated embodiments are related to the above references. Figures 2A to 7B The descriptions are similar; the following mainly describes... Figure 8 The differences between the illustrated embodiments are as follows. See also: Figure 8 As shown, in this embodiment, the end of the first bending region 51 in its bending direction is inserted into the radially adjacent first bending region 51, and a gap may be left between the ends of the two first bending regions 51 in their bending direction to utilize the gap for heat insulation. By setting the adjacent first bending regions 51 to be intercalated, the number of uncoated areas 18a layers above the same diaphragm 122 can be increased, and the first bending regions 51 are continuous in the radial direction without gaps, which can reduce the risk of light leakage and further avoid the risk of burns to the diaphragm 122.

[0094] In this embodiment, the end of the second bending region 52 in its bending direction is also inserted into the radially adjacent second bending region 52. By setting the adjacent second bending regions 52 to be interlocked, the number of uncoated regions 18a layers on the same diaphragm 122 can be increased, and the second bending regions 52 are continuous and gapless in the radial direction, which can reduce the risk of light leakage and further avoid the risk of burns to the diaphragm 122. In some embodiments, the first straight section 512 of the adjacent first bending region 51 can be welded to the first collector plate 201, increasing the number of uncoated regions 18a layers that can be welded to the first collector plate 201 above the diaphragm 122.

[0095] In this embodiment, at least the outermost ring of the electrode assembly 120 may not have tabs with a first bending region 51 and a second bending region 52, thus preventing the first bending region 51 and the second bending region 52 from exceeding the outer diameter of the body of the electrode assembly 120.

[0096] Figure 9 This is a cross-sectional schematic diagram of an electrode assembly according to another embodiment. Figure 9 Several aspects of the illustrated embodiments are related to the above references. Figure 8 The descriptions are similar; the following mainly describes... Figure 9 The differences between the illustrated embodiments are as follows. See also: Figure 9 As shown, the first bending area 51 bends towards the first side S1, that is, towards the winding center hole 120c. The first bending area 51 contacts the diaphragm 122 located on the first side S1 of the first current collector 18 and presses down on the diaphragm 122 to bend it. When the bending point of the first bending area 51 is lower than the end of the diaphragm 122 away from the first active material layer 16, the diaphragm 122 will be squeezed and bent below the first bending area 51. This increases the distance between the welding area of ​​the first current collector 201 and the diaphragm 122, reducing the possibility of the diaphragm 122 being burned. This avoids the heat generated during welding of the second bending area 52 from affecting the diaphragm 122 and causing the diaphragm 122 to be burned.

[0097] In some embodiments, the projection of the first bending region 51 in direction D1 can completely cover the diaphragm 122 in contact with the first bending region 51. That is, the bent diaphragm 122 does not extend beyond the first bending region 51. Thus, the portion of the diaphragm 122 that extends beyond the first bending region 51 can be prevented from shrinking due to welding heat, which could lead to an internal short circuit.

[0098] More specifically, the diaphragm 122 has a segment 122s that extends beyond the first active material layer 16 in direction D1. The extension distance of segment 122s beyond the first active material layer 16 is 0.5mm-3mm. In this embodiment, segment 122s contacts and bends with the first bending region 51. The extension distance of segment 122s refers to the length of segment 122s itself in a straight state. If the extension distance of segment 122s is greater than 3mm, the diaphragm 122 is too long, resulting in waste, and it is also easy for the diaphragm 122 to extend beyond the first bending region 51, which is prone to heat shrinkage. If the extension distance of segment 122s is less than 0.5mm, assembly errors may cause the diaphragm 122 to fail to provide effective insulation, leading to a short circuit.

[0099] It should also be understood that although only one first bending region 51 is shown in the above embodiment, in other embodiments, along direction D1, the uncoated area 18a may also have another first bending region 51 on the side of the second bending region 52 away from the first active material layer 16. Therefore, in direction D1, the uncoated area 18a may have two first bending regions 51, and the second bending region 52 is located between the two first bending regions 51. The two first bending regions 51 have the same bending direction in the radial direction (e.g., both towards the winding center hole 120c), and the two first bending regions 51 and the second bending region 52 have opposite bending directions in the radial direction. In such an embodiment, the first bending region 51 located at the upper end (farther from the first active material layer 16) can be used for welding with the first manifold 201 or the cover plate assembly 220, and the first bending region 51 located at the lower end (closer to the first active material layer 16) can serve as an obstacle in the laser path or form a heat insulation space. This can improve the laser welding process window, improve the welding quality, and avoid burning the diaphragm 122. In addition, setting two first bending zones 51 can avoid wasting space due to an excessive number of first bending zones 51.

[0100] Embodiments of this application also provide a battery pack 1002 (see...) Figure 1 The battery pack 1002 includes any of the aforementioned secondary batteries 100, and the battery pack 1002 may have the beneficial effects described above regarding the secondary battery 100.

[0101] Embodiments of this application also provide an electronic device 1000 (see Figure 1 The electronic device 1000 includes the aforementioned battery pack 1002, and the electronic device 1000 may have the beneficial effects described above with respect to the secondary battery 100 and / or battery pack 1002.

[0102] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A single-cell battery, characterized in that, include: The housing is equipped with electrode terminals; An electrode assembly, housed within the housing, includes a first electrode, a second electrode, and a diaphragm disposed between the first electrode and the second electrode. The first electrode includes a first current collector and a first active material layer. The first current collector includes a coated area coated with the first active material layer and an uncoated area not coated with the first active material layer. The uncoated area is electrically connected to the electrode terminal. The direction from the coated area to the uncoated area is a first direction. An adapter component is located on the side of the electrode assembly adjacent to the uncoated area along the first direction. The adapter component is welded to the uncoated area to form a solder mark. The welding direction between the adapter component and the uncoated area is in the opposite direction to the first direction. The uncoated area of ​​the first current collector has a first bending area and a second bending area arranged sequentially in the first direction. The first bending area and the second bending area bend in opposite directions in the radial direction of the electrode assembly. The projection of the first bending area in the first direction covers the diaphragm on a first side of the first current collector. The first side is the side to which the bending direction of the first bending area points. The projection of the solder mark in the first direction covers the diaphragm covered by the first bending area.

2. The single-cell battery according to claim 1, characterized in that, The adapter is a collector plate, wherein the first bending area and the second bending area are connected by a first straight section, and the first straight section is welded to the collector plate.

3. The single-cell battery according to claim 1, characterized in that, The adapter is a collector plate, wherein the first bending area and the second bending area are connected by a first straight section, and the solder mark between the collector plate and the uncoated area is spaced apart from the first straight section.

4. The single-cell battery according to claim 2 or 3, characterized in that, The uncoated area also includes a straight connecting section, which is connected to the end of the second bending area away from the coated area. The straight connecting sections of the multiple uncoated areas are stacked in the first direction and welded to the collector plate.

5. The single-cell battery according to any one of claims 1 to 3, characterized in that, The first bending area includes a rounded corner, a first straight section, and a second straight section. The first straight section connects to the end of the rounded corner that is away from the coating area, and the second straight section connects to the end of the rounded corner that is adjacent to the coating area. The minimum distance between the first straight section and the second straight section in the first direction is a, where a ≥ 2b, and b is the thickness of the first current collector.

6. The single-cell battery according to claim 1, characterized in that, The first bending area contacts the diaphragm located on the first side of the first current collector, and presses down on the diaphragm to bend it.

7. The single-cell battery according to claim 6, characterized in that, The projection of the first bending area fully covers the diaphragm that contacts the first bending area.

8. The single-cell battery according to claim 7, characterized in that, The diaphragm has a segment that extends beyond the first active material layer in the first direction, and the extension distance of the segment beyond the first active material layer is 0.5 mm to 3 mm.

9. The single-cell battery according to claim 1, characterized in that, The second electrode includes a second current collector and a second active material layer covering a portion of the surface of the second current collector. In the first direction, the height of the first active material layer exceeding the second current collector is greater than 1 mm.

10. The single-cell battery according to claim 9, characterized in that, The second current collector includes a coated area coated with the second active material layer and an uncoated area not coated with the second active material layer. The coated area and the uncoated area of ​​the second current collector are arranged adjacent to each other in the opposite direction to the first direction. The housing is further provided with another electrode terminal, and the uncoated area of ​​the second current collector is electrically connected to the other electrode terminal.

11. The single-cell battery according to any one of claims 1 to 3, characterized in that, The first bending region is inserted at its end in the bending direction into the first bending region adjacent in the radial direction.

12. The single-cell battery according to claim 1, characterized in that, Also includes: A finishing insulating tape is used to secure the end of the diaphragm. The electrode assembly includes a body, which includes the coating area of ​​the first active material layer and the first current collector. There are multiple uncoated areas, and each of the second bending areas is located within the projection range of the body and the tail insulating tape in the first direction.

13. The single-cell battery according to claim 1, characterized in that, Along the first direction, the uncoated area also has another first bending area on the side of the second bending area away from the first active material layer.

14. The single-cell battery according to claim 1, characterized in that, The housing includes an end wall and a side wall connected to the edge of the end wall. One end of the side wall along the first direction has an opening, and a groove protruding radially inward along the opening is provided on the side wall adjacent to the opening. The electrode assembly is located between the end wall and the groove. The adapter is a collector plate, which is connected to the side of the roller groove facing the electrode assembly.

15. The single-cell battery according to claim 1, characterized in that, The housing has an opening at one end of its sidewall along the first direction, and the housing further includes a cover plate assembly that covers the opening; the connecting component is the cover plate assembly. The uncoated area is welded to the cover plate assembly, and the cover plate assembly is electrically connected to the electrode terminal; The first bending area and the second bending area are connected by a first straight section; the first straight section is welded to the cover plate assembly, or the weld mark between the cover plate assembly and the uncoated area is spaced apart from the first straight section.

16. The single-cell battery according to any one of claims 1 to 3, 6-10, and 12-15, characterized in that, In the first direction, the distance between the first bending area and the first active material layer is d, 0.5mm≤d≤2.5mm.

17. The single-cell battery according to claim 1, characterized in that, The electrode terminal is the housing, or the electrode terminal is a pole connected to the housing.

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