Cylindrical battery, battery pack, and electronic device

Abstract

The utility model provides a kind of cylindrical battery, battery pack and electronic device, cylindrical battery includes: shell;Electrode assembly is arranged in shell;Cover plate with support part;Current collector disc, current collector disc includes body, transition piece, transition piece is welded to the side of body towards cover plate and forms first welding portion, the material of body and transition piece is different, and the material of transition piece and cover plate is same;Support part and transition piece are welded and form second welding portion, and body and electrode assembly are welded and form third welding portion;Along the radial direction of shell, first welding portion and support part are set in dislocation, transition piece has center line, first welding portion is set between the radial direction inside one end of transition piece, center line, and third welding portion is set in the radial direction inside of second welding portion.The utility model at least improves the welding yield between cover plate, current collector disc.

Description

Technical Field

[0001] This utility model relates to a cylindrical battery, a battery pack, and an electronic device. Background Technology

[0002] In the field of new energy batteries, cylindrical batteries are being used more and more widely. For example, cylindrical batteries (such as lithium-ion batteries) can be used in electronic devices such as cars, energy storage, mobile phones, digital products, power tools, power units, and energy storage devices.

[0003] Cylindrical batteries typically consist of a casing and an electrode assembly. The electrode assembly includes a positive electrode, a first separator, a negative electrode, and a second separator, which are stacked sequentially to form a wound electrode assembly or a stacked electrode assembly. This assembly is then placed inside the casing and sealed by a cover that closes the casing opening. The cover also needs to be welded to the current collector, which is electrically connected to the electrode assembly. However, if the current collector and the cover are typically made of dissimilar materials, the welding yield between the cover and the current collector is low due to differences in melting points and coefficients of thermal expansion. Utility Model Content

[0004] In view of the problems existing in the related technologies, the purpose of this utility model is to provide a cylindrical battery, battery pack and electronic device to improve the welding yield between the cover plate and the current collector.

[0005] To achieve the above objectives, this utility model provides a cylindrical battery, comprising: a casing with an opening at one end; an electrode assembly disposed within the casing; a cover plate covering the opening, the cover plate having a support portion protruding towards the electrode assembly; and a current collector disposed between the cover plate and the electrode assembly, the current collector comprising a body and a transition member, the transition member being welded to the side of the body facing the cover plate to form a first weld portion, the body and the transition member being made of different materials, the transition member being made of the same material as the cover plate; the support portion being welded to the transition member to form a second weld portion, and the body being welded to the electrode assembly to form a third weld portion; wherein, along the radial direction of the casing, the first weld portion and the support portion are offset, the transition member has a center line, the first weld portion is disposed between one radially inner end of the transition member and the center line, and the third weld portion is disposed radially inner to the second weld portion.

[0006] In some embodiments, the first weld portion is disposed at one end radially inner to the transition member.

[0007] In some embodiments, an explosion-proof valve is provided on the cover plate, the electrode assembly is a wound member with a winding center hole, the current collector is provided with a weak portion, the projection of the weak portion along the axis of the housing at least partially coincides with the winding center hole, the weak portion is configured to tear in the event of thermal runaway of the cylindrical battery, and in the axial direction of the cylindrical battery, the weak portion of the current collector is offset toward the cover plate relative to the transition member.

[0008] In some embodiments, the thickness of the transition piece is less than the thickness of the main body of the manifold; and / or, the thickness of the transition piece is less than the thickness of the cover plate.

[0009] In some embodiments, the support portion forms a groove on the outer side of the cover plate, and the sidewall and bottom wall of the groove are connected by a rounded transition area, the projection of the rounded transition area on the collector plate covering the first welded portion.

[0010] In some embodiments, the electrode assembly has at least one first tab on the side facing the cover plate. Along the axial direction of the housing, the first tab is covered by the support portion to form a first region. Along the radial direction of the housing, the first tab includes a second region located radially inside the first region. The support portion presses against the first region through a collector plate. The axial height of the first region is less than the axial height of the second region.

[0011] In some embodiments, the transition member is annular, and the first weld portion is a continuously extending annular weld mark around the transition member.

[0012] In some embodiments, the projection of the support portion along the axis of the housing is arc-shaped, the second weld portion is an arc-shaped weld line and / or the material of the support portion of the transition piece and the cover plate is steel.

[0013] Embodiments of this application also provide a battery pack, including any of the cylindrical batteries described above.

[0014] Embodiments of this application also provide an electronic device including a battery pack of any of the above.

[0015] The beneficial technical effects of this utility model are at least as follows:

[0016] The embodiments of this application at least improve the welding yield between the cover plate and the manifold. Attached Figure Description

[0017] 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.

[0018] Figure 1 A schematic diagram of an electronic device, using a vehicle as an example, is shown.

[0019] Figure 2 A perspective view of a cylindrical battery according to an embodiment of this application is shown.

[0020] Figure 3 A top view schematic diagram of a cylindrical battery according to an embodiment of this application is shown.

[0021] Figure 4 It shows along Figure 3 A schematic diagram of a cross-section taken from section AA.

[0022] Figure 5 It shows Figure 4 A magnified view of a portion of region F in the middle.

[0023] Figure 6 It shows Figure 4 A top view of the CIMC flow plate.

[0024] Figure 7 It shows Figure 6 Schematic diagram of the BB section.

[0025] Figure 8A It shows Figure 7 A magnified view of a portion of region C.

[0026] Figure 8B It shows Figure 7 A comparative example of welding the transition piece to the body in region C.

[0027] Figure 8C It shows Figure 7 A comparative example of welding the transition piece to the body in region C.

[0028] Figure 9 A three-dimensional schematic diagram of a cover plate according to some embodiments of this application is shown.

[0029] Figure 10 Another three-dimensional schematic diagram of a cover plate according to some embodiments of this application is shown. Detailed Implementation

[0030] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] For ease of description, "first," "second," "third," etc., can be used in this article to distinguish different components of a figure or a series of figures. "First," "second," "third," etc., are not intended to describe the corresponding components.

[0035] See Figure 1 This utility model provides an electronic device 1000, which includes a battery pack 1002. The working part of the electronic device 1000 is electrically connected to the battery pack 1002 to obtain electrical power. As an example, the electronic device 1000 is a vehicle, which 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 operation or the operation of its internal electrical components. However, in other embodiments, the electronic device 1000 can also be a mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, and power tool, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; the working part can obtain electrical power from the battery pack 1002 and perform corresponding functions, such as a fan blade rotation unit or a vacuum cleaner 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.

[0036] The electrode assembly 120 of the cylindrical battery 100 is mainly formed by winding and placing a positive electrode sheet and a negative electrode sheet, and typically a first separator and a second separator are provided between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet includes a positive current collector and a positive active material layer, the positive active material layer being coated on the surface of the positive current collector; the positive current collector includes a positive electrode coating area and a positive electrode tab connected to the positive electrode coating area, the positive electrode coating area being coated with the positive active material layer, and the positive electrode tab not being coated with the positive active material layer. The negative electrode sheet includes a negative current collector and a negative active material layer, the negative active material layer being coated on the surface of the negative current collector; the negative current collector includes a negative electrode coating area and a negative electrode tab connected to the negative electrode coating area, the negative electrode coating area being coated with the negative active material layer, and the negative electrode tab not being coated with the negative active material layer. Taking a lithium-ion battery as an example, the positive electrode current collector can be made of aluminum, and the positive electrode active material layer includes positive electrode active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode current collector can be made of copper, and the negative electrode active material layer includes negative electrode active material, which can be carbon or silicon, etc. The first and second separators can be made of PP or PE, etc. To protect and insulate the electrode assembly 120, an insulating film can be wrapped around the outside of the electrode assembly 120. The insulating film can be synthesized from PP, PE, PET, PVC, or other polymer materials.

[0037] For ease of explanation, the following embodiments use a vehicle as an example to illustrate the concept of electronic device 1000. See also Figure 1 The vehicle is equipped with a battery pack 1002, 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. Figure 2 A perspective view of a cylindrical battery 100 according to an embodiment of this application is shown.

[0038] Figure 3 A top view schematic diagram of a cylindrical battery 100 according to some embodiments of this application is shown. Figure 4 It shows along Figure 3 A schematic diagram of a cross-section taken from section AA. Figure 5 It shows Figure 4 A magnified view of a portion of region F in the middle. See also... Figure 3 , Figure 4 as well as Figure 5The cylindrical battery 100 includes: a housing 200, one end of which is an opening 201; an electrode assembly 120 disposed in the housing 200; a cover plate 300 covering the opening 201, the cover plate 300 having a support portion 302 protruding toward the electrode assembly 120; and a current collector 400 disposed between the cover plate 300 and the electrode assembly 120. The current collector 400 includes a body 404 and a transition member 405. The transition member 405 is welded to the side of the body 404 facing the cover plate 300 to form a first weld portion 500. The body 404 and the transition member 405 are made of different materials, while the transition member 405 and the cover plate 300 are made of the same material. The support portion 302 is welded to the transition member 405 to form a second weld portion, and the body 404 is welded to the electrode assembly 120 to form a third weld portion. Along the radial direction X of the housing, the third weld portion is disposed radially inside the second weld portion.

[0039] It should be noted that the fact that the transition piece 405 and the cover plate 300 are made of the same material means that the main components of the transition piece 405 and the cover plate 300 are the same. It does not require that the components of the two are completely identical. For example, the transition piece 405 and the cover plate 300 can be made of steel. Low carbon steel, medium carbon steel and high carbon steel are all the same material. For example, the cover plate 300 can be made of high carbon steel and the transition piece 405 can be made of medium carbon steel.

[0040] Figure 6 It shows Figure 4 A top view of CIMC 400. Figure 7 It shows Figure 6 Schematic diagram of the BB section. Figure 8A It shows Figure 7 A magnified view of a portion of region C. Please refer to [link / reference]. Figure 6 Along the radial direction X of the housing 200, the first welded portion 500 is offset from the support portion 302. For details, please refer to... Figure 8A When the transition piece 405 is welded to the body 404, a first welded part 500 (i.e., a weld mark) can be formed by welding from the side of the transition piece 405. The surface of the first welded part 500 is not flat. If the first welded part 500 and the support part 302 are not misaligned, i.e., opposite to each other, the fit between the support part 302 and the transition piece 405 will be low, i.e., a gap may be generated between the two. Then a welding gap will be generated between the transition piece 405 and the support part 302 of the cover plate 300, resulting in a low welding yield.

[0041] In one embodiment, the transition member 405 is disposed in the edge region of the body 404. Specifically, the transition member 405 may be annular, for example, the transition member 405 may overlap with the outer periphery of the body 404, or the outer periphery of the transition member 405 may overlap with the outer periphery of the body 404. In another embodiment, there may be multiple transition members 405, each transition member 405 being arc-shaped and distributed circumferentially at intervals in the body 404.

[0042] Among them, the transition member 405 has a centerline G along the radial direction of the collector plate 400. It is understood that, please refer to... Figure 6 When the transition member 405 is annular, its center line G can be a loop, and the first weld portion 500 can also be an annular weld mark surrounding the transition member 405. When the transition member 405 is arc-shaped, its center line G can be an arc, and the first weld portion 500 can also be an arc. In this application, the first weld portion 500 is disposed between one radially inner end of the transition member 405 and the center line G. Specifically, the transition member 405 has a center line G that bisects the width of the transition member 405 in the radial direction X of the housing 200. In the radial direction X, the first weld portion 500 where the body 404 and the transition member 405 are welded is located at a position offset from the center line G towards the axis H.

[0043] Since the transition piece 405 is first welded to the body 404 and then welded to the cover plate 300, the collector plate 400 and the transition piece 405 are dissimilar materials. Higher welding power is required during welding. The collector plate 400 and the transition piece 405 are usually made thin, which makes them prone to thermal deformation due to welding heat effects. Figure 8B It shows Figure 7 A comparative example of welding the transition piece 405 in region C to the body 404. See also Figure 8B Along the radial direction X of the housing 200, if the first welded portion 500 formed by welding the transition member 405 to the body 404 is disposed on the radial outer side of the transition member 405 (between the center line G and the radial outer end), a gap will be generated between the radial inner side of the transition member 405 and the collector plate 400 due to heat; and the support portion 302 presses against the transition member 405 at the edge region of the radial outer side of the collector plate 400, causing the collector plate 400 to tilt, and causing the edge region of the radial outer side of the collector plate 400 to be closer to the electrode assembly 120 relative to the center region of the collector plate 400. Furthermore, since there needs to be no gap between the support part 302 and the collector plate 400 when welding the support part 302 and the collector plate 400, the contact surface and compressive force between the part of the support part 302 near the radial X outer side and the transition piece 405 need to be larger. However, compressing the gap between the radial inner side of the transition piece 405 and the collector plate 400 may cause the first welded part 500 to break. If the gap between the radial inner side of the transition piece 405 and the collector plate 400 is not reduced, during the welding process between the transition piece 405 and the support part 302, due to the thinness of the transition piece 405 and the existence of this gap, defects such as bursting points or incomplete welds are likely to occur when the transition piece 405 is welded to the body 404.

[0044] As in the embodiments of this application, see Figure 8AWhen the first welded part 500 is disposed between the radial inner end of the transition member 405 and the center line G along the radial X of the housing 200, a gap will be generated between the radial outer end of the transition member 405 and the body 404 due to the thermal deformation of the welding. The support part 302 and the transition member 405 abut against each other in the edge area of ​​the collector plate 400, causing the collector plate 400 to tilt and its edge area to be closer to the electrode assembly 120 than the center area of ​​the collector plate 400. That is to say, the contact surface and the compressive force between the part of the support part 302 closer to the radial X interior and the transition member 405 are greater. And its close arrangement with the first welded part 500 can increase the contact area between the transition member 405 and the body 404, and improve the flow capacity of the collector plate 400.

[0045] Figure 8C It shows Figure 7 A comparative example of welding the transition piece 405 in region C to the body 404. See also Figure 8C Along the radial direction X of the housing 200, if the transition member 405 and the body 404 of the collector plate 400 are welded together to form two spaced first welded parts 500, the heat will cause a gap to be generated between the transition member 405 and the body 404 between the two first welded parts 500, reducing the contact area between the transition member 405 and the body 404. Compared with forming only one first welded part 500, the flow capacity of the collector plate 400 is reduced; and the contact area between the transition member 405 and the support part 302 is small, making it difficult to weld.

[0046] In some embodiments, the housing 200 is made of materials such as copper, iron, aluminum, steel, or aluminum alloy, preferably steel (e.g., SPCC) for higher strength. To prevent the housing 200 from rusting during long-term use, a rust-preventive material such as metallic nickel can be plated on the surface of the housing 200. The electrode assembly 120 is sealed and installed inside the housing 200.

[0047] Preferably, the first weld portion 500 for welding the body 404 and the transition member 405 is provided at one end of the transition member 405 along the radial X, specifically at the annular inner surface 4052, and the support portion 302 can press against the portion of the transition member 405 that is located radially outward relative to the center line G, so as to further avoid the generation of gaps between the body 404 and the transition member 405.

[0048] See also Figure 4 , Figure 5 ,and Figure 6In some embodiments, the electrode assembly 120 is a wound component with a winding center hole 121, and an explosion-proof valve is provided on the cover plate 300 for relieving pressure in the event of thermal runaway of the cylindrical battery. Specifically, the explosion-proof valve can be a notch 304. The collector plate 400 is provided with a weak portion 401, the projection of the weak portion 401 along the axis H of the housing 200 at least partially coincides with the winding center hole 121, and the weak portion 401 is configured to tear in the event of thermal runaway of the cylindrical battery 100. In the axial direction of the cylindrical battery 100 (i.e., the axial direction Z of the housing), the weak portion 401 is offset towards the cover plate 300 relative to the transition member 405. The area where the weak portion 401 is located overlaps with the center of the collector plate 400. Alternatively, the center of the collector plate 400 may have a through hole, and the weak portion 401 may be located in or near the area where the central through hole is located. The orthogonal projection of the weak portion 401 may be entirely located within the area defined by the winding center hole 121. The weak part 401 is thinner than the surrounding collector plate 400, hence it is called the weak part.

[0049] The weak portion 401 can be a groove, tangent, or polygonal opening penetrating the collector plate 400, or it can be a thinned portion. In some embodiments, the weak portion 401 is an opening penetrating the collector plate 400, and the weak portion 401 can be a polygonal opening. In other embodiments, the weak portion 401 includes a groove or tangent. For example, the weak portion 401 can have a polygonal shape surrounded by multiple grooves or tangents, or the weak portion 401 can be multiple grooves or tangents extending radially X along the central through-hole of the collector plate 400. The weak portion 401 can also be any other suitable structure that locally thins the central region of the collector plate 400.

[0050] Along the axial direction Z, the central region of the collector plate 400 is offset toward the cover plate 300 relative to the edge region, causing the weak part 401 located in the central region to tilt and offset toward the cover plate 300 relative to the transition piece 405 located radially outside the collector plate 400, forming a collector plate structure that is raised toward the cover plate at the weak part 401.

[0051] During battery thermal runaway, the gas venting path is from the electrode assembly 120 towards the cover plate 300. By providing a weak section 401 in the central region of the current collector 400, and by setting the current collector 400 such that the weak section 401 in the central region is offset towards the cover plate 300 relative to the edge region of the current collector 400, the current collector 400 can be more easily torn at the weak section 401 during battery thermal runaway. This prevents the current collector 400 from blocking the explosion-proof valve on the cover plate 300 during thermal runaway, ensuring that the battery can release pressure normally and improving battery safety.

[0052] In some embodiments, a stress relief groove 406 is also provided on the collector plate 400. The stress relief groove 406 is disposed on the body 404, and in the radial direction of the collector plate 400, the stress relief groove 406 is located between the weak part 401 and the transition member 405. By providing the stress relief groove 406, the occurrence of stress concentration areas in the collector plate 400 can be better avoided, which facilitates the deformation of the collector plate 400 to further tilt, that is, the central area of ​​the collector plate 400 is offset towards the cover plate 300 relative to the edge area.

[0053] See Figure 7 and Figure 8A In some embodiments, the thickness of the transition member 405 is less than the thickness of the body 404 of the current collector 400; and / or, the thickness of the transition member 405 is less than the thickness of the cover plate 300. If the body 404 of the current collector 400 is thicker, it is less likely to deform and tilt; if the transition member 405 is too thick, it will waste the space within the housing 200 for accommodating the electrode assembly 120, reduce the energy density of the cylindrical battery 100, and increase the weight of the cylindrical battery 100.

[0054] See back Figure 5 In some embodiments, the support portion 302 forms a groove on the outer side of the cover plate 300, the groove having a bottom wall 3021 facing and welded to the transition member 405. Specifically, in some embodiments, the side wall 3022 of the groove and the bottom wall 3021 are connected by a rounded transition region 3023. Specifically, as long as the end of the rounded transition region 3023 that connects to the bottom wall 3021 is spaced apart from the first welded portion 500 in the radial X direction, the projection of the rounded transition region 3023 on the collector plate 400 covers the first welded portion 500, and the rounded transition region 3023 avoids the first welded portion 500, thus preventing the presence of the first welded portion 500 from affecting the fit between the support portion 302 and the transition member 405; of course, the projection of the rounded transition region 3023 on the collector plate 400 may also avoid the first welded portion 500 instead of covering it. Of course, to avoid the first weld portion 500, the rounded transition area 3023 can be omitted. Instead, in the radial direction X, the bottom wall 3021 is directly connected to the side wall 3022 of the groove closer to the axis H, and the connection point between the bottom wall 3021 and the side wall 3022 is offset from the first weld portion 500. If the body 404 is welded to the transition piece 405 on the side of the body 404 facing the electrode assembly 120, an uneven surface of the solder joint will appear on the side of the body 404 facing the electrode assembly 120, which may cause the solder joint to scratch the tabs of the electrode assembly 120.

[0055] See also Figure 5In some embodiments, the electrode assembly 120 has at least one tab at each end of the cylindrical battery 100 in the height direction (a first tab 1201 on the side of the electrode assembly 120 facing the cover plate 300 and a second tab on the opposite side of the first tab 1201), and the first tab 1201 and the second tab have opposite polarities, with the first tab 1201 being the negative tab. It should be noted that in other embodiments, the first tab 1201 may also be the positive tab, and the second tab may be the negative tab. In some embodiments, both the first tab 1201 and the second tab are both double tabs.

[0056] In some embodiments, along the axial direction Z of the housing 200, the area covered by the support portion 302 of the first electrode tab 1201 is a first region 1211; along the radial direction X of the housing 200, the area radially inner to the first region 1211 of the first electrode tab 1201 is a second region 1212; the support portion 302 presses against the first region 1211 through the collector plate 400, and the height of the first region 1211 along the axial direction Z is less than the height of the second region 1212 along the axial direction Z. It can be understood that by welding the bottom wall 3021 of the support portion 302 to the transition member 405, the bottom wall 3021 of the support portion 302 is press-fitted to the transition member 405, so that the height of the first region 1211 of the first electrode tab 1201 within the area covered by the transition member 405 along the axial direction Z is less than the height of the second region 1212 along the axial direction Z. Over-pressing can be understood as the support portion 302 over-pressing the transition piece 405 so that the transition piece 405 just presses against the tab 1201 without applying pressure to the tab 1201, until the tab 1201 is further compressed to compress the first region 1211 of the tab 1201. Compared to the second region 1212 that is not pressed by the support portion 302, the first region 1211 of the first tab 1201 has a smaller height in the axial Z direction. By over-pressing the transition piece 405 in this way, the fit and contact area between the body 404 of the current collector 400 and the transition piece 405 are increased, and the current flow area when the current flows from the current collector 400 to the cover plate 300 is increased accordingly.

[0057] See also Figure 5 In some embodiments, the thickness of the transition member 405 in the axial direction Z is less than the thickness H1 of the cover plate 300. The transition member 405 and the support portion 302 of the cover plate 300 are made of steel, and the body 404 of the collector plate 400 is made of copper. Figure 5 The thickness of cover plate 300 is illustrated by H1. In fact, cover plate 300 can be a one-piece molded part formed by stamping.

[0058] See Figure 5As mentioned above, the first surface of the body 404 facing the electrode assembly 120 is welded to the first tab 1201 to form a third welded portion. It is understood that before welding the body 404 to the first tab 1201 of the electrode assembly 120, a nickel layer can be plated on the second surface of the body 404 facing away from the first surface. The welding of the body 404 to the electrode assembly 120 can be performed using laser penetration welding. By placing this nickel layer on the second surface where the laser is incident, problems such as reflection and bursts during welding can be prevented, thus avoiding affecting the welding effect. After welding is completed, the plated nickel layer will remain on the second surface of the body 404. Of course, since the third welded portion can be a weld mark formed by the melting of the body 404 and the first tab 1201, nickel will also be present in the weld mark formed by the melting of the body 404 and the first tab 1201.

[0059] See further Figure 6 and Figure 8A In some embodiments, the transition member 405 is lap-welded to the side of the body 404 facing the transition member 405 via a first weld portion 500, the first weld portion 500 being a circumferential weld mark extending continuously around the axis H. This circumferential weld portion 500 avoids the problem of deformation and bulging of the non-welded area of ​​the annular inner surface 4052 of the transition member 405 caused by intermittent welding. Furthermore, it is understood that the aforementioned lap welding, for example, involves the transition member 405 lapping onto the body 404, with a laser beam obliquely entering from the joint to complete the welding.

[0060] In some embodiments, a first weld portion 500 is formed by laser welding on the annular inner surface 4052 of the manifold 400 on the side where the transition member 405 is provided. It is understood that the welding laser starts from the transition member 405 side to avoid the difficulty of determining the position of the transition member 405 when welding from the body 404 side, thus increasing the positioning difficulty. It should be understood that in the aforementioned welding position, the formed first weld portion 500 penetrates the transition member 405 and extends into the interior of the body 404.

[0061] Figure 9 and Figure 10 A three-dimensional schematic diagram of a cover plate 300 according to some embodiments of this application is shown.

[0062] Figure 9 The example shown is the side of the cover plate 300 facing outwards from the housing 200 when it is assembled into the housing 200.

[0063] Figure 10The example shown is the side of the cover plate 300 facing inwards from the housing 200 when assembled into the housing 200. In some embodiments, the cover plate 300 has an outer peripheral edge 301 welded to the opening 201, and the cover plate 300 is also provided with a plurality of support portions 302 arranged circumferentially around the axis H of the housing 200, with an exhaust passage 303 formed between each two adjacent support portions 302 located inside the housing 200, and the exhaust passage 303 extending radially.

[0064] Embodiments of this application also provide a battery pack 1002, including any of the cylindrical battery 100 described above, and the battery pack 1002 may have the beneficial effects described above with respect to the cylindrical battery 100.

[0065] Embodiments of this application also provide an electronic device 1000, including a battery pack 1002 of any of the above, and the electronic device 1000 may have the beneficial effects described above with respect to the cylindrical battery 100.

[0066] The above-mentioned technical solution provided in this application at least prevents welding gaps from forming between the transition piece and the support part of the cover plate, resulting in a low welding yield.

[0067] 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 cylindrical battery, characterized in that, include: A housing, one end of which is open; Electrode assembly, disposed within the housing; A cover plate that covers the opening, the cover plate having a support portion that protrudes toward the electrode assembly; A current collector is disposed between the cover plate and the electrode assembly. The current collector includes a body and a transition member. The transition member is welded to the side of the body facing the cover plate to form a first welded part. The body and the transition member are made of different materials, while the transition member and the cover plate are made of the same material. The support part is welded to the transition member to form a second welded part. The body and the electrode assembly are welded to form a third welded part. In this configuration, the first welded portion is offset from the support portion along the radial direction of the housing. The transition member has a center line. The first welded portion is located between the radially inner end of the transition member and the center line. The third welded portion is located radially inner to the second welded portion.

2. The cylindrical battery according to claim 1, characterized in that, The first welded portion is disposed at one end of the radially inner side of the transition member.

3. The cylindrical battery according to claim 1, characterized in that, An explosion-proof valve is provided on the cover plate. The electrode assembly is a wound component with a central winding hole. The current collector has a weak portion, the projection of which along the axis of the housing at least partially coincides with the central winding hole. The weak portion is configured to tear in the event of thermal runaway of the cylindrical battery. Wherein: in the axial direction of the cylindrical battery, the weak part of the current collector is offset toward the cover plate relative to the transition member.

4. The cylindrical battery according to claim 3, characterized in that, The thickness of the transition piece is less than the thickness of the body of the collector plate; and / or, the thickness of the transition piece is less than the thickness of the cover plate.

5. The cylindrical battery according to claim 2, characterized in that, The support portion forms a groove on the outer side of the cover plate, and the sidewall and bottom wall of the groove are connected by a rounded transition area. The projection of the rounded transition area on the collector plate covers the first welded portion.

6. The cylindrical battery according to claim 3, characterized in that, The electrode assembly has at least one first electrode tab on the side facing the cover plate. Along the axial direction of the housing, the area covered by the support portion of the first electrode tab is a first region; along the radial direction of the housing, the first electrode tab includes a second region located radially inside the first region; The support portion presses against the first region via the collection plate, and the height of the first region along the axial direction is less than the height of the second region along the axial direction.

7. The cylindrical battery according to claim 1, characterized in that, The transition piece is annular, and the first welded portion is a continuous annular weld mark extending around the transition piece.

8. The cylindrical battery according to any one of claims 1 to 7, characterized in that, The projection of the support portion along the axis of the housing is arc-shaped, and the second weld portion is an arc-shaped weld line; and / or, The transition piece and the support portion of the cover plate are made of steel.

9. A battery pack, characterized in that, The cylindrical battery includes any one of claims 1 to 8.

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

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