Secondary battery, battery pack, and electronic device
By designing a current collector structure with the bridging part protruding from the welding area and adopting a short straight-line welding method, the problem of unstable welding between the current collector and the groove in cylindrical batteries was solved, thus improving welding reliability and battery safety.
Patent Information
- Application Number
- CN202520251524.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-17
- Publication Date
- 2026-01-09
- Estimated Expiration
- 2035-02-17
AI Technical Summary
The welding of the current collector and groove in existing cylindrical batteries is unstable, resulting in insufficient welding reliability, which affects the safety performance and production yield of the batteries.
Design a collector plate structure in which the bridging part is configured to protrude from the welding area between the first collector plate and the groove, and is connected by short straight line welds to avoid pulling welding, improve welding reliability, and enhance stability through contact between the bridging part and the cover plate.
This improves the welding reliability of the current collector and the groove, reduces the welding difficulty, and ensures battery safety and production yield.
Smart Images
Figure CN223785276U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a secondary battery, a battery pack, and an electronic device. Background Technology
[0002] In the field of new energy power batteries, the application of secondary batteries is becoming increasingly widespread. For example, secondary batteries (such as lithium-ion batteries) can be used in electronic devices such as cars, energy storage, mobile phones, tablets, wearable devices, power banks, e-cigarettes, digital products, power tools, power devices, and energy storage devices.
[0003] One type of rechargeable battery is the cylindrical battery. Cylindrical batteries (such as the 46-series cylindrical batteries with a diameter of 46) have become increasingly popular in recent years. Cylindrical batteries, combined with Cell-to-Chassis (CTC) technology, can significantly improve the energy density of the entire battery pack. Because CTC technology requires steel casings for the cells, resulting in a heavier overall structure, 46-series cylindrical batteries often require high-energy-density positive and negative electrode materials to increase the battery's energy density. In this context, improving battery safety performance is particularly important. Another advantage of cylindrical batteries is their production cycle time, which offers a significant increase in production capacity compared to prismatic cells. Therefore, improving yield in the cylindrical battery manufacturing process is a crucial technical challenge. Utility Model Content
[0004] In view of the problems existing in the related technologies, the purpose of this utility model is to provide a secondary battery, battery pack and electronic device, so as to at least improve the reliability of the current collector welding.
[0005] To achieve the above objectives, embodiments of this application provide a secondary battery, comprising: a housing having a sidewall with an opening, and a groove protruding into the housing near the opening; an electrode assembly housed within the housing, the groove restricting movement of the electrode assembly in the height direction of the secondary battery, the electrode assembly having a tab at one end near the groove in the height direction, the tab bending toward a central hole of the electrode assembly, and the tab closest to the outer edge of the electrode assembly forming an outer ring tab of the electrode assembly; and a current collector including a main body, a plurality of second extensions, and a plurality of first extensions disposed between the main body and the plurality of second extensions. The main body is disposed between the groove and the electrode assembly. One side surface of the main body is electrically connected to the tab. The first extension is located on the same plane as the main body. The first extension extends radially outward from the outer edge of the main body to contact at least part of the outer ring tab. One end of the second extension is connected to the main body between two adjacent first extensions, and the other end is electrically connected to the groove. The second extension includes a groove fixing part and a bridging part. The two ends of the bridging part are respectively connected to the outer edge of the main body and the groove fixing part. The groove fixing part is welded to the side of the groove away from the electrode assembly and welded. The bridging part protrudes from the weld away from the electrode assembly along the height direction.
[0006] In some embodiments, the secondary battery further includes a cover plate that seals the opening; wherein a portion of the bridging portion contacts the side of the cover plate facing the electrode assembly.
[0007] In some embodiments, the bridging portion contacts one side of the cover plate in a compressed state, and the compression amount of the bridging portion along the height direction is 0.5 mm to 1.5 mm, wherein the compression amount is the compression deformation size generated along the height direction when the bridging portion is compressed into contact with the cover plate.
[0008] In some embodiments, the surface of the cover plate facing the electrode assembly has a groove, the bridging portion has a top end furthest from the electrode assembly along the height direction, and the distance between the centerline of the groove extending along the height direction and the top end in the radial direction of the housing ranges from -5 mm to 10 mm.
[0009] In some embodiments, the secondary battery further includes an insulating element disposed between the cover plate and the side wall of the housing; the edge portion of the surface of the cover plate is covered by the insulating element, and the bridging portion contacts the surface between the groove and the insulating element.
[0010] In some embodiments, the minimum distance between the end of the bridging portion connected to the outer edge of the main body and the outer peripheral surface of the electrode assembly along the radial direction of the housing is d1, and the range of d1 is 2.4mm-5mm.
[0011] In some embodiments, the bridging portion includes a thinned area, the thickness of which is less than the thickness of the other portions of the bridging portion.
[0012] In some embodiments, the housing is electrically connected to the negative electrode tab of the electrode assembly, the housing is made of steel, and the current collector is made of copper or nickel; or, the housing is electrically connected to the positive electrode tab of the electrode assembly, the housing is made of aluminum, and the current collector is made of aluminum.
[0013] In some embodiments, the secondary battery is a cylindrical battery.
[0014] Embodiments of this application also provide a battery pack, including any of the above-described secondary batteries.
[0015] Embodiments of this application also provide an electronic device including any of the above-described secondary batteries or battery packs.
[0016] The above-mentioned technical solution of this application, by configuring the bridging part of the collector plate to protrude from the weld mark formed by welding between the first collector plate and the groove, can avoid pulling the weld mark between the collector plate and the groove, thereby improving the welding reliability of the collector plate and the groove. 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 cross-sectional schematic diagram of a secondary battery is shown.
[0019] Figure 2 A perspective view of a secondary battery according to an embodiment of this application is shown.
[0020] Figure 3 A schematic diagram of the structure of an electrode assembly according to an embodiment of this application is shown.
[0021] Figure 4 A perspective view of a first collector disk according to an embodiment of this application is shown.
[0022] Figure 5 A top view schematic diagram of a first collector disk according to an embodiment of this application is shown.
[0023] Figure 6 The diagram shows a schematic projection of the first current collector along the Z direction onto the plane containing the outer ring electrode after the first current collector is welded to the first electrode tab according to an embodiment of this application.
[0024] Figure 7A schematic diagram showing the state of the electrode assembly with the first collector plate welded on according to an embodiment of this application placed inside the housing.
[0025] Figure 8 A schematic diagram showing the state of the welding connection process between the first manifold and the housing according to an embodiment of this application is shown.
[0026] Figure 9 A schematic diagram showing the fit between the press-fitting tooling and the groove fixing part according to an embodiment of this application is shown.
[0027] Figure 10 A schematic diagram of the structure of a secondary battery according to an embodiment of this application is shown.
[0028] Figure 11A for Figure 10 A magnified view of a portion of the image.
[0029] Figure 11B yes Figure 11A A magnified view of the contact point between the bridging section and the cover plate.
[0030] Figure 12 A top view of a secondary battery after removing the cover plate according to an embodiment of this application is shown.
[0031] Figure 13 This is a partially enlarged schematic diagram of a portion of the bridging section according to some embodiments.
[0032] Figure 14 A schematic diagram of an electronic device for a vehicle according to an embodiment of this application is shown. Detailed Implementation
[0033] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] Figure 1 A schematic cross-sectional view of a secondary battery is shown. (Reference) Figure 1 As shown, a mainstream packaging method for cylindrical batteries employs a groove sealing process, forming a groove 101 on one side of the electrode assembly 2 to restrict the movement of the electrode assembly 2 in the height direction. Alternatively, lap welding is currently a mainstream packaging method, in which the first current collector 3 is lapped and welded to the side of the groove 101 facing away from the electrode assembly 2, connecting the tabs of the electrode assembly 2 adjacent to the groove 101 to the housing via the first current collector 3. However, this current packaging method is not conducive to the charging of the bottom cover plate on the side of the groove 101, resulting in a reliability defect in this design.
[0039] Figure 2 A perspective view of a secondary battery 100 according to an embodiment of this application is shown. Figure 3 A schematic diagram of the electrode assembly 2 in this embodiment is shown. The electrode assembly 2 is formed by winding a positive electrode sheet, a separator, and a negative electrode sheet. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive current collector includes a coated area and an uncoated area. The positive active material layer is coated on the coated area of the positive current collector, while the uncoated area of the positive current collector forms a positive electrode tab. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative current collector includes a coated area and an uncoated area. The negative active material layer is coated on the coated area of the negative current collector, while the uncoated area of the negative current collector forms a negative electrode tab (such as the first tab 20).
[0040] As a specific example, the positive electrode current collector can be made of aluminum, and the positive electrode active material layer includes a 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 a negative electrode active material, which can be carbon or silicon, etc. The separator can be made of PP (polypropylene) or PE (polyethylene), etc. To protect and insulate the electrode assembly 2, an insulating film can be wrapped around it. The insulating film can be synthesized from PP, PE, PET (polyethylene terephthalate), PVC (polyvinyl chloride), or other polymer materials.
[0041] Continue to refer to Figure 3 In this configuration, multiple first electrodes 20 are bent and stacked. In some embodiments, the first electrodes 20 are negative electrodes. To form such a configuration... Figure 3 The first tab 20 shown can be implemented in various ways. For example, one specific implementation method is to cut and stack the uncoated area of the negative current collector, dividing it into multiple tabs, and then flatten it from the height direction of the electrode assembly, so that the first tab 20 is parallel to the end face of the electrode assembly 2, thereby facilitating welding with the first current collector plate (such as the first current collector plate 3 described below) to be introduced later. Although Figure 3 The state of the second electrode (positive electrode) is not shown, but it can be understood that the positive electrode can have a similar state to the first electrode 20, which will not be described in detail here.
[0042] Among the multiple first tabs 20, the first tab 20 that bends towards the center hole 21 of the electrode assembly 2 and is closest to the outer edge of the electrode assembly 2 constitutes the outer ring tab 201 of the electrode assembly 2. It should be noted that the outer ring tab 201 refers to the outermost bent first tab 20, and not necessarily the outermost first tab 20. This is because, in some embodiments, such as... Figure 2 As shown (direction A is the direction away from the central hole 21), the outermost first electrode tab 20 is not bent, and this first electrode tab 20 is not the outer ring electrode tab 201 described in this article.
[0043] Figure 4 A three-dimensional schematic diagram of the first collector disk 3 in this embodiment is shown. Figure 5 A top view of the first collector plate 3 in this embodiment is shown. Although Figure 5 The first collector disk 3 in the middle is not displayed. Figure 4 The opening shown is acceptable, but it is understandable. Figure 4 The first collector plate 3 in the figure can actually have similar openings, but they are not shown in this figure.
[0044] like Figure 4As shown, the first current collector 3 includes a main body 30, a plurality of first extensions 31, and a plurality of second extensions 32, with the plurality of first extensions 31 disposed between the main body 30 and the plurality of second extensions 32. The main body 30 may be annular. In this embodiment, the four first extensions 31 are located on the same plane as the main body 30. The first extensions 31 extend radially outward from the outer edge of the main body 30, forming a petal-like shape. Here, "the first extensions 31 and the main body 30 are on the same plane" means that both the first extensions 31 and the main body 30 are mainly electrically connected to the first tabs 20 of the electrode assembly 2, and since the first tabs 20 are basically located on the same plane, the first extensions 31 and the main body 30 are also basically located on the same plane. It should be noted that "the same plane" here includes the same plane or approximately the same plane, because after the secondary battery undergoes processing, formation, and charging and discharging, the first extensions 31 and the main body 30 may undergo some deformation (e.g., some dents), but in this case, it can still be considered that the first extensions 31 and the main body 30 are on the same plane.
[0045] The second extension 32 may include a groove fixing portion 321 and a bridging portion 322. One end of the bridging portion 322 is connected to the main body portion 30 between two adjacent first extensions 31, and the other end is connected to the groove fixing portion 321. The groove fixing portion 321 is used for conductive connection with the groove 101 of the housing 1, which will be described in detail later. However, it should be noted here that since the plane where the groove 101 of the housing 1 is located is offset from the plane where the first electrode tab 20 is located in the height direction (i.e., the Z direction) of the electrode assembly 2, therefore, as Figure 4 As shown, the groove fixing part 321 is offset from the main body part 30 and the first extension part 31 in the Z direction, and the bridging part 322 has a height in the Z direction.
[0046] like Figure 5 As shown, the outer edges of the plurality of first extensions 31 and the plurality of second extensions 32 essentially achieve 360° circumferential coverage. It is understood that the shape of the main body 30, the number and shape of the first extensions 31, and the number and shape of the second extensions 32 shown in the illustrated embodiment are merely examples and do not constitute a limitation on the present invention. In other embodiments, the number of first extensions 31 and second extensions 32 may be three or six.
[0047] The following describes the process of connecting the first current collector 3 to the electrode assembly 2 and the housing 1. First, the first current collector 3 is welded to the first tab 20, such that the main body 30 and the first extension 31 of the first current collector 3 are connected to the first tab 20, and the first extension 31 extends radially outward from the outer edge of the main body 30 to contact at least a portion of the outer ring tab 201. Next, the electrode assembly 2 with the first current collector 3 welded to it is placed into the housing 1, i.e., the housing insertion step is performed.
[0048] Figure 6 This embodiment shows a schematic diagram of the projection of the first current collector 3 along the Z direction onto the plane where the outer ring electrode 201 is located after the first current collector 3 is welded to the first electrode tab 20. Figure 6 As shown, the projection of the first collector disk is projection 903. Since the first extension 31 is parallel to the plane where the first electrode 20 is located, and the first extension 31 is connected to the first electrode 20, the projection 9031 of the first extension and the first extension 31 are substantially completely overlapping in shape.
[0049] refer to Figure 6 ,by Figure 6 Taking the two first extension projections 9031 at the top center and the outer edge projection 9032 between the two first extension projections 9031 as examples, the left first extension projection 9031 at least partially overlaps with the outer ring tabs 201a, 201b, 201c, 201d, and 201e (each outer ring tab 201a, 201b, 201c, 201d, and 201e corresponds to one tab), and the right first extension projection 9031 at least partially overlaps with the outer ring tabs 201j, 201k, 201m, and 201n. Each of the outer ring tabs 201f, 201g, 201h, and 201i between the two first extension projections 9031 (i.e., between the two first extensions 31 corresponding to the two first extension projections 9031) at least partially overlaps with the outer edge projection 9032 of the second extension 32.
[0050] In the above text, the projection 9031 of the first extension on the left side overlaps at least partially with the outer ring tabs 201a, 201b, 201c, 201d, and 201e, indicating that the first extension 31 corresponding to the projection 9031 of the first extension is in contact with the outer ring tabs 201a, 201b, 201c, 201d, and 201e. This can prevent the outer ring tabs 201a, 201b, 201c, 201d, and 201e from turning outward due to the influence of process steps (such as airflow) during the process of entering the housing. Similarly, the projection 9031 of the first extension on the right side overlaps at least partially with the outer ring tabs 201j, 201k, 201m, and 201n, indicating that the first extension 31 corresponding to the projection 9031 contacts the outer ring tabs 201j, 201k, 201m, and 201n, thereby preventing the outer ring tabs 201j, 201k, 201m, and 201n from turning outward. The projection 9032 of the outer edge of the second extension 32 between the two projections 9031 overlaps at least partially with each of the outer ring tabs 201f, 201g, 201h, and 201i, indicating that the outer edge of the second extension 32 corresponding to the projection 9032 can prevent the outer ring tabs 201f, 201g, 201h, and 201i from turning outward during insertion into the housing, thus avoiding affecting the diameter of the electrode assembly 2.
[0051] Figure 7 This diagram illustrates the state of the electrode assembly 2, with the first collector plate 3 welded to it, after it is placed inside the housing 1 in this embodiment. Figure 7 As shown, the free end of the bridging portion 322 (i.e. the end away from the main body portion 30) can be tilted upward in the Z direction, thereby avoiding the hob 500 used for machining the groove 101, so as to avoid interference from the first collector plate 3 during the machining of the groove 101.
[0052] Figure 8 This diagram illustrates the welding process between the first collector plate 3 and the housing 1 in this embodiment. (Reference) Figure 8After the electrode assembly 2 with the first collector plate 3 welded to it is placed into the housing 1, a groove 101 recessed into the housing 1 can be formed on the side wall 10 of the housing 1 near the opening 12 using a tool such as a hobbing cutter 500. The groove 101 has a first wall 1011 and a second wall 1012 spaced apart in the Z direction. The second wall 1012 restricts the movement of the electrode assembly 2 in the Z direction within the housing 1. The free end of the bridging portion 322 is connected to the groove fixing portion 321. For the purpose of avoiding the hobbing cutter 500 as described above, the groove fixing portion 321 is tilted upwards without the action of external force, thus creating a certain distance between it and the first wall 1011. In order to weld the groove fixing portion 321 to the first wall 1011, a press-fitting fixture 8 can be used. The press-fitting fixture 8 applies external force to the second extension portion 32, causing the bridging portion 322 to bend and the groove fixing portion 321 to fit against the first wall 1011.
[0053] Figure 9 This diagram illustrates the engagement of the press-fitting fixture 8 with the groove fixing part 321 in this embodiment. (See reference) Figure 9 The press-fitting fixture 8 includes a first presser 81, a second presser 82, and a third presser 83. The first presser 81 and the second presser 82 press against the two ends of the groove fixing part 321, respectively, and the third presser 83 presses against the middle position of the groove fixing part 321. With the first presser 81, the second presser 82, and the third presser 83 pressing against the two ends and the middle position of the groove fixing part 321, welding marks are made between the first presser 81 and the third presser 83, and between the second presser 82 and the third presser 83. In this embodiment, two short straight weld marks 4 are formed. According to the above welding method, by using the press-fitting fixture 8 with the third presser 83, a pressure point is added in the middle of the groove fixing part 321, and two short straight weld marks 4 are formed, replacing the welding method in the prior art that forms a longer arc weld mark. In this way, since the welding adopts the form of short straight weld marks 4, there is no need to rotate the electrode assembly 2 during the welding process, thereby reducing the welding difficulty and improving the welding stability. At the same time, this method can effectively avoid the problem of poor contact caused by the possibility of a burst point in the middle of the weld mark when forming a long arc weld mark in the prior art. It should be understood that in other embodiments, the welding of the groove fixing part 321 and the first wall 1011 can also form weld marks with other structures.
[0054] Then, the opening 12 of the housing 1 can be sealed using the cover plate 5 to obtain the secondary battery 100. Figure 10 A schematic diagram of the secondary battery 100 in this embodiment is shown. Figure 10As shown, the secondary battery 100, as a specific example, is a cylindrical battery. The secondary battery 100 includes: a housing 1, an electrode assembly 2, terminals 7, a cover plate 5, a first current collector 3, and a second current collector 6. The housing 1 includes a cylindrical sidewall 10 and an end wall 13 located at one end of the sidewall 10. The electrode assembly 2 is housed inside the housing 1. The terminals 7 pass through mounting holes in the end wall 13 and are insulated from the end wall 13 by an insulating element. The cover plate 5 covers and seals an opening 12 at the end of the sidewall 10 away from the end wall 13. A groove 101 recessed into the housing 1 is formed on the sidewall 10 near the opening 12. The first current collector 3 is connected to the negative electrode tab of the electrode assembly 2 and the groove 101 of the housing 1, and the second current collector 6 is connected to the positive electrode tab of the electrode assembly 2 and the terminal 7.
[0055] The specific dimensions of the housing 1 can be determined based on the specific dimensions of the electrode assembly 2, for example, a diameter of 46mm and heights of 80mm, 95mm, or 120mm. The housing 1 can be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy. To prevent rusting during long-term use, a rust-preventive material, such as nickel, can be plated onto the surface of the housing 1.
[0056] Figure 11A for Figure 10 A magnified view of a portion of the image. (Reference) Figure 11A The main body 30 of the first collector plate 3 is located between the groove 101 and the electrode assembly 2 in the Z direction. The surface 51 of the main body 30 facing the electrode assembly 2 is adjacent to the first tab 20 on the negative electrode side of the electrode assembly 2. Figure 11A (Not shown in the image) Conductive connection.
[0057] The secondary battery 100 is a cylindrical battery 100. For the cylindrical battery 100, the electrode assembly 2 is inserted into the housing 1 from the negative electrode side and sealed on the negative electrode side. The cylindrical battery 100 has a notch 400 on the cover plate 5 on the negative electrode side. The notch 400 can be annular in shape. The notch 400 can be a weak area of the cover plate 5, and therefore can be used as an explosion-proof valve to relieve pressure on the negative electrode side. Therefore, the assembly process, assembly quality, and structure from the insertion of the electrode assembly 2 into the housing 1 to the sealing will affect the pressure relief effect of the cylindrical battery 100. The main functions of the explosion-proof valve include pressure release, prevention of explosion, protection of battery structure, and safety protection. When the internal pressure of the lithium battery rises abnormally, the explosion-proof valve will automatically open to release the gas accumulated inside, thereby reducing the pressure and preventing the battery from rupturing or exploding.
[0058] Figure 12This diagram shows a top view of the secondary battery 100 after the cover plate 5 has been removed in this embodiment. At this time, the first current collector 3 is electrically connected to the first tab 20 and the groove 101. In this embodiment, when the first current collector 3 is electrically connected to the first tab 20 but not yet electrically connected to the groove 101, this is a projection diagram of the first current collector 3 along the Z direction onto the plane containing the outer tab 201. Although the position of the second extension 32 changes slightly before and after being electrically connected to the groove 101, this change is subtle. Therefore, it can be referenced... Figure 6 To understand the projection of the first current collector 3 along the Z direction onto the plane where the outer ring tab 201 is located in the secondary battery 100 after it leaves the factory.
[0059] In some embodiments, reference Figure 11A The second extension 32 includes a groove fixing portion 321 and a bridging portion 322. The two ends of the bridging portion 322 are respectively connected to the outer edge of the main body 30 and the groove fixing portion 321. The groove fixing portion 321 is welded to the side of the groove 101 away from the electrode assembly 2 and a solder mark 4 is formed (see, for example, see...). Figure 9 The bridging portion 322 protrudes from the solder stamp away from the electrode assembly 2 in the Z direction (i.e., protrudes from the surface of the groove fixing portion 321 facing away from the groove 101). In some embodiments, the bridging portion 322 is a bent portion that partially protrudes from the solder stamp.
[0060] The above-mentioned technical solution of this application, by configuring the bridging part 322 of the first collector plate 3 to protrude from the weld mark formed by welding between the first collector plate 3 and the groove 101, can avoid the first collector plate 3 pulling on the weld mark between it and the groove 101, thereby improving the welding reliability of the first collector plate 3 and the groove 101.
[0061] Furthermore, a portion of the bridging portion 322 contacts the cover plate 5 facing the surface 51 of the electrode assembly 2. By setting the bridging portion 322 to partially contact the cover plate 5, it is ensured that the bridging portion 322 protrudes from the solder mark between the first collector plate 3 and the groove 101, and the robustness of the fit between the first collector plate 3 and the cover plate 5 is ensured.
[0062] Figure 11B yes Figure 11A A partially enlarged schematic diagram of the contact point between the bridging portion 322 and the cover plate 5. (See also...) Figure 11BIn some embodiments, the bridging portion 322 contacts the surface 51 of the cover plate 5 in a compressed state, and the compression amount d3 of the bridging portion 322 along the height direction is 0.5 mm to 1.5 mm. The compression amount d3 can refer to the compression deformation size generated along the height direction when the bridging portion 322 of the first collector plate 3 contacts the cover plate 5. This compression deformation may be caused by the large protrusion of the bridging portion 322 away from the electrode assembly 2. When the cover plate 5 is closed, the bridging portion 322 will be compressed by the pressure of the cover plate 5, forming a compression deformation. When the cover plate 5 is removed, the bridging portion 322 will recover and rebound 0.5 mm to 1.5 mm of the compression amount d3 along the height direction away from the electrode assembly 2. Preferably, d3 is 1 mm. The above-mentioned range of values for d3 can ensure the reliability of the fit between the first collector plate 3 and the cover plate 5, and will not cause damage to the first collector plate due to excessive compression of the bridging portion 322.
[0063] The bridging portion 322 has a tip 322a furthest from the electrode assembly 2 along the height direction. It should be understood that this tip 322a can refer to the end of the bridging portion 322 in the state not compressed by the cover plate 5. The distance d2 between the centerline Lc of the notch 400 and this tip 322a in the radial direction of the housing is given by the distance d2, where the centerline Lc is located at the center of the notch 400 and extends in the direction Z along the radial direction of the housing. In some embodiments, d2 ranges from -5 mm to 10 mm. The tip 322a of the bridging portion 322 is typically located outside the annular region of the notch 400 to avoid the bridging portion 322 compressing the weak area of the cover plate 5 (i.e., the notch 400) and causing a reduction in the explosion-proof pressure. By avoiding the influence of the contact position between the bridging portion 322 and the cover plate 5 on the notch 400, the robustness of the explosion-proof valve is ensured. In a preferred embodiment, d2 can be 3 mm. In some embodiments, the top end 322a of the bridging portion 322 may also be within the annular region of the notch 400, in which case d2 is defined as a negative value.
[0064] More specifically, in combination Figure 11A and Figure 11B As shown, an insulating member 180 may be provided between the cover plate 5 and the side wall 10 of the housing to electrically insulate the side wall 10 from the cover plate 5. The edge portion of the surface 51 of the cover plate 5 facing the electrode assembly 2 is covered by the insulating member 180. The bridging portion 322 contacts the surface 51 of the cover plate 5 between the notch 400 and the insulating member 180, that is, the contact position between the bridging portion 322 and the surface 51 is located in the area between the notch 400 and the insulating member 180. By setting the bridging portion 322 to contact the cover plate 5 between the notch 400 and the insulating member 180, interference of the bridging portion 322 with the explosion-proof area of the notch 400 can be avoided, ensuring the robustness of the explosion-proof valve and improving battery safety.
[0065] The minimum radial distance d1 between the end of the bridging portion 322 connected to the outer edge of the main body 30 and the outer peripheral surface of the electrode assembly 2 is d1, and d1 ranges from 2.4mm to 5mm. In a preferred embodiment, d1 can be 2.8mm. The above-mentioned range of d1 can increase the effective area for welding the first current collector and the electrode assembly, and reduce the internal resistance of the battery. This ensures that the welding area meets the resistance requirements of the cell, while avoiding increased pulling on the d1 position when the bridging portion 322 is pressed down.
[0066] Figure 13 This is a partially enlarged schematic diagram of the bridging portion 322 according to some embodiments. (See reference) Figure 13 As shown, the bridging portion 322 is a bent portion. The bending angle of the bent portion can be designed to reach the range of values for parameters such as d1, d2, and d3 mentioned above. Upsetting design or adding scribing lines can be used to bend the bridging portion 322. Preferably, the bridging portion 322 includes an upsetting region 322t, the thickness of which can be less than the thickness of the other parts 322e of the bridging portion 322. The upsetting design can prevent breakage during bending to form the bridging portion 322, ensuring bending reliability.
[0067] The material of the first current collector 3 can be determined according to the corresponding electrode polarity. When the housing 1 is electrically connected to the positive electrode tab of the electrode assembly 2 (i.e., the first electrode tab 20 is the positive electrode tab), the first current collector 3 is used to connect the positive current collector. The material of the housing is aluminum, and the material of the current collector is aluminum.
[0068] When the housing 1 is electrically connected to the negative electrode tab of the electrode assembly (i.e., the first tab 20 is the negative electrode tab), the first current collector 3 is used to connect to the negative current collector. The housing is made of steel, and the current collector is made of copper or nickel, or copper plated with nickel. The above material selection for the first current collector 3 can reduce the bending stiffness of the first current collector 3, improve the bending effect, and expand the application scenarios of lap welding in lithium-ion batteries.
[0069] Embodiments of this application also provide a battery pack, such as the battery pack 1002 described above. The battery pack may include a secondary battery 100 of any of the above embodiments, and the battery pack may have the beneficial effects described above regarding the secondary battery 100.
[0070] Embodiments of this application also provide an electronic device that may include the secondary battery 100 of any of the above embodiments, and the electronic device may have the beneficial effects described above with respect to the secondary battery 100.
[0071] This utility model 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 14The 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. An electronic device 1000 includes the 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, power tool, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; the working unit can obtain electrical energy from the battery pack 1002 and perform corresponding work, such as the fan blade rotation unit of a fan, the vacuuming unit of a vacuum cleaner, etc. 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. The embodiments of this application do not impose special limitations on the above-mentioned electronic device 1000.
[0072] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A secondary battery, characterized in that, include: A housing having a sidewall with an opening, and a groove protruding inward into the housing from a position adjacent to the opening. An electrode assembly is housed in the housing. The groove restricts the movement of the electrode assembly in the height direction of the secondary battery. The electrode assembly has a tab at one end in the height direction near the groove. The tab is bent toward the central hole of the electrode assembly, and the tab closest to the outer edge of the electrode assembly constitutes the outer ring tab of the electrode assembly. as well as The collector plate includes a main body, a plurality of second extensions, and a plurality of first extensions disposed between the main body and the plurality of second extensions. The main body is disposed between the groove and the electrode assembly, and one side surface of the main body is electrically connected to the tab. The first extension portion is located on the same plane as the main body portion, and the first extension portion extends radially outward from the outer edge of the main body portion until it contacts at least a portion of the outer ring tab. One end of the second extension is connected to the main body portion between two adjacent first extensions, and the other end is electrically connected to the groove. The second extension includes a groove fixing part and a bridging part. The two ends of the bridging part are respectively connected to the outer edge of the main body and the groove fixing part. The groove fixing part is welded to the side of the groove away from the electrode assembly to form a weld mark. The bridging part protrudes from the weld mark away from the electrode assembly along the height direction.
2. The secondary battery according to claim 1, characterized in that, Also includes: Cover plate, sealing the opening; A portion of the bridging portion contacts the side of the cover plate facing the electrode assembly.
3. The secondary battery according to claim 2, characterized in that, The bridging portion contacts one side of the cover plate under compressed conditions, and the compression amount of the bridging portion along the height direction is 0.5 mm to 1.5 mm. Wherein, the compression amount is the compression deformation size generated along the height direction when the bridging part comes into compression contact with the cover plate.
4. The secondary battery according to claim 2, characterized in that, in, The cover plate has grooves on its surface facing the electrode assembly. The bridging portion has a top end furthest from the electrode assembly along the height direction, and the distance between the centerline of the groove extending along the height direction and the top end in the radial direction of the housing ranges from -5mm to 10mm.
5. The secondary battery according to claim 4, characterized in that, Also includes: An insulating element is disposed between the cover plate and the side wall of the housing; The edge portion of the surface of the cover plate is covered by the insulating element, and the bridging portion contacts the surface of the cover plate between the groove and the insulating element.
6. The secondary battery according to claim 4, characterized in that, The minimum distance between the end of the bridging portion connected to the outer edge of the main body and the outer peripheral surface of the electrode assembly along the radial direction of the housing is d1, and the range of d1 is 2.4mm-5mm.
7. The secondary battery according to claim 1, characterized in that, The bridging portion includes a thin upsetting area, the thickness of which is less than the thickness of the other portions of the bridging portion.
8. The secondary battery according to claim 2, characterized in that, The housing is electrically connected to the negative electrode tab of the electrode assembly; the housing is made of steel, and the current collector is made of copper or nickel; or The housing is electrically connected to the positive electrode tab of the electrode assembly, and the housing is made of aluminum, as is the current collector. The secondary battery is a cylindrical battery.
9. A battery pack, characterized in that, Includes the secondary battery as described in any one of claims 1 to 8.
10. An electronic device, characterized in that, Includes the battery pack as described in claim 9.