Secondary battery and electronic device

Abstract

The utility model provides a secondary battery which comprises a shell which comprises an end wall which is provided with a first assembly hole; the lower plastic is in contact with the lower surface, facing the interior of the shell, of the end wall, and the lower plastic is provided with a second assembly hole corresponding to the first assembly hole; the pole comprises a columnar part and an inner flange, the columnar part penetrates through the first assembly hole and the second assembly hole, and the inner flange is connected with one end, located in the shell, of the columnar part and clamps the lower plastic together with the end wall; the lower surface, deviating from the end wall, of the lower plastic is provided with a lower clamping groove, and the inner flange is connected with the lower clamping groove in a buckled mode. The utility model aims to provide a secondary battery and an electronic device so as to at least reinforce a matching structure between a pole and a shell and reduce the risk that the pole flies out when the secondary battery is in thermal runaway.

Description

Technical Field

[0001] This utility model relates to a secondary battery 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. Utility Model Content

[0003] In view of the problems existing in the related technologies, the purpose of this utility model is to provide a secondary battery and electronic device, so as to at least strengthen the fitting structure between the terminal and the shell, and reduce the risk of the terminal flying out when the secondary battery is thermally runaway.

[0004] To achieve the above objectives, this utility model provides a secondary battery, comprising: a housing, including an end wall having a first mounting hole; a lower plastic contacting the lower surface of the end wall facing the interior of the housing, the lower plastic having a second mounting hole corresponding to the first mounting hole; and an electrode post including a columnar portion and an inner flange, the columnar portion passing through the first and second mounting holes, the inner flange being connected to one end of the columnar portion located inside the housing and clamping the lower plastic together with the end wall; wherein, a lower retaining groove is provided on the lower surface of the lower plastic facing away from the end wall, and the inner flange is engaged with the lower retaining groove.

[0005] In some embodiments, the upper surface of the lower plastic facing the end wall is provided with an upper groove, and the end wall is provided with a protruding rib that engages with the upper groove.

[0006] In some embodiments, the inner flange is a hook-shaped structure with an opening facing the end wall, the hook-shaped structure having a tail portion that engages in a lower slot and a main body portion that connects the tail portion to the columnar portion.

[0007] In some embodiments, the end of the end wall facing the pole is extruded into the housing to form a rib.

[0008] In some embodiments, the surface of the main body of the inner flange facing the end wall is a concave surface, and the lower plastic has a protrusion that mates with the concave surface.

[0009] In some embodiments, the tail of the inner flange is a second bent portion that bends and extends toward the lower slot, and the second bent portion is engaged with the lower slot.

[0010] In some embodiments, the rib is spaced apart from the first mounting hole along the radial direction of the first mounting hole.

[0011] In some embodiments, the height H1 of the second bend is greater than 0.3 mm, and the width H2 of the second bend is greater than 0.3 mm.

[0012] In some embodiments, the width of the rib is in the range of 0.3mm-2mm, and the height of the rib is in the range of 0.3mm-2mm.

[0013] Embodiments of this application also provide an electronic device including any of the above-described secondary batteries.

[0014] The beneficial technical effects of this utility model are at least as follows:

[0015] In this embodiment, the lower surface of the plastic part away from the end wall is provided with a lower groove, and the inner flange is engaged with the lower groove, which at least strengthens the fit structure between the electrode and the shell and reduces the risk of the electrode flying out when the secondary battery experiences thermal runaway. Attached Figure Description

[0016] 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.

[0017] Figure 1 A partial cross-sectional schematic diagram of a prior art secondary battery is shown.

[0018] Figure 2 A schematic diagram is shown when the electronic device according to an embodiment of this application is a vehicle.

[0019] Figure 3 A perspective view of a secondary battery according to an embodiment of this application is shown.

[0020] Figure 4 A partial cross-sectional schematic diagram of a secondary battery according to an embodiment of this application is shown.

[0021] Figure 5 It shows Figure 4 An enlarged schematic diagram of region A in the middle.

[0022] Figure 6 A half-sectional perspective view of the lower plastic according to an embodiment of this application is shown.

[0023] Figure 7 A partial cross-sectional schematic diagram of a secondary battery according to another embodiment of this application is shown.

[0024] Figure 8 It shows Figure 7 Enlarged schematic diagram of region B in the middle.

[0025] Figures 9-11A partial cross-sectional schematic diagram of the assembly process of a secondary battery according to another embodiment of this application is shown. Detailed Implementation

[0026] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] Figure 1 A partial cross-sectional schematic diagram of a prior art secondary battery is shown; see [link / reference]. Figure 1The existing secondary battery 1 includes a casing 2, a lower plastic 3, and an electrode post with an inner flange 4. The inner flange 4 is substantially parallel to the inner surface of the casing 2 and together with it clamps the inner surface of the lower plastic 3. The inner surface of the casing 2 is also substantially planar. Furthermore, the mating interface between the lower plastic 3 and the casing 2 and the inner flange 4 is also substantially continuous and flat, without any concave-convex fit. Since the existing secondary batteries 1 are basically lithium-ion batteries, and lithium batteries undergo various electrochemical and thermodynamic reactions during storage, charging, and discharging, in the event of an extreme event, lithium batteries are prone to thermal runaway, instantaneous short circuit, and release of a large amount of heat, causing the battery temperature to rise sharply. This can lead to smoke or spontaneous combustion in electronic devices such as automobiles equipped with the existing secondary battery 1, resulting in dangerous accidents. This extreme phenomenon is often simulated through a nail penetration test at the battery level. In the nail penetration test, when a needle penetrates the casing 2 of the secondary battery 1 and a short circuit occurs, a large amount of gas is rapidly generated inside the secondary battery 1, and the internal temperature of the secondary battery 1 also rises rapidly. When high temperature and pressure are generated inside the secondary battery 1, the casing 2 will warp and deform, which in turn will cause deformation of the casing area that mates with the inner flange 4. Since the metal strength of the casing 2 is greater than that of the inner flange 4, the compressed lower plastic 3 will also rebound. The inner flange 4, originally parallel to the inner surface of the casing 2, will warp and deform accordingly, opening towards the interior of the casing 2. When the diameter of the opened end of the inner flange 4 is smaller than the aperture of the casing 2, the terminal of the secondary battery 1 will fly out. After the terminal flies out, the charged / conductive material burning inside the secondary battery 1 will further fly out from the aperture of the casing 2, leading to system-level thermal runaway. Furthermore, since the terminal of the secondary battery 1 is itself conductive, after flying out, it will connect with the positive and negative terminals of the system / other secondary batteries 1, causing further thermal runaway. Therefore, how to strengthen the fit between the inner flange of the secondary battery and the lower plastic and casing to prevent the terminal of the secondary battery from flying out and causing greater thermal runaway in the event of thermal runaway is an urgent problem to be solved.

[0032] This utility model provides an electronic device 1000. In some embodiments, the electronic device 1000 may include a battery pack, a battery group 1002, an electric vehicle, an energy storage cabinet, etc. For ease of explanation, the following embodiments will use a vehicle as an example to illustrate the electronic device 1000. Figure 2 A schematic diagram of an electronic device according to an embodiment of this application is shown when it is a vehicle. See also Figure 2The vehicle's interior may also include another electronic device 1000, which can be a battery pack 1002. The battery pack 1002 may 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 may be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles may 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 some other embodiments, the electronic device 1000 may 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'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.

[0033] Figure 3 A perspective view of a secondary battery according to an embodiment of this application is shown. Figure 4 A partial cross-sectional schematic diagram of a secondary battery according to an embodiment of this application is shown. See also: Figure 3 and Figure 4This application provides a secondary battery 100, which includes a housing 200, an electrode assembly located within the housing 200, a current collector, and terminal posts 50 mounted on the housing 200. The housing 200 includes an end wall 111 and side walls surrounding the end wall 111. The housing 200 can be formed in various ways, such as integral stamping, integral casting, or separate welding, as long as a stable seal and electrical connection can be established. A receiving cavity is formed within the housing 200 to accommodate the electrode assembly, electrolyte, current collector, and other necessary battery components. Specifically, the diameter of the housing 200 can be determined according to the specific dimensions of the electrode assembly. The housing 200 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 metallic nickel can be plated onto the surface of the housing 200. The secondary battery 100 can be a cylindrical battery, such as a 4680 cylindrical battery with a height of 80mm and a diameter of 46mm; or a battery with a height of 15mm and a diameter of 46mm.

[0034] Electrode assemblies are components in the secondary battery 100 where electrochemical reactions occur. The housing 200 may contain one or more electrode assemblies. The electrode assembly is a wound or stacked electrode assembly, including a stacked and / or wound positive electrode, a first separator, a negative electrode, and a second separator. The positive electrode includes a positive current collector and a positive active material layer coated on the positive current collector. A first coated area coated with the positive active material layer and a first uncoated area without the positive active material layer are formed on the positive current collector. The first coated area and the first uncoated area are arranged along the height direction of the electrode assembly. The first uncoated area extends beyond the separator at one end in the height direction of the secondary battery 100, forming a bent positive electrode tab. The negative electrode includes a negative current collector and a negative active material layer coated on the negative current collector. A second coated area with the negative active material layer and a second uncoated area without the negative active material layer are formed on the negative current collector. The second coated area and the second uncoated area are arranged along the height direction of the electrode assembly. The second uncoated area also extends towards one end of the secondary battery 100 in the height direction to the outside of the separator, forming a bent negative electrode tab. The first separator and the second separator are disposed between the positive electrode and the negative electrode to isolate the positive and negative active material layers. Taking the lithium-ion secondary battery 100 as an example, the material of the positive current collector can be aluminum, and the positive active material layer includes positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The material of the negative current collector can be copper, and the negative active material layer includes negative active material, which can be carbon or silicon, etc. The substrate material of the first separator and the second separator can be PP (polypropylene) or PE (polyethylene), etc. To protect and insulate the electrode assembly, an insulating film can be wrapped around the outside of the electrode assembly. The insulating film can be synthesized from PP, PE, PET, PVC or other polymer materials.

[0035] refer to Figure 4In some embodiments, the end wall 111 has a first mounting hole 1110, the upper plastic 121 contacts the surface of the end wall 111 facing the outside of the housing 200, and the lower plastic 131 contacts the surface of the end wall 111 facing the inside of the housing 200. The upper plastic 121 has a third mounting hole 1210 corresponding to the first mounting hole 1110, and the lower plastic 131 has a second mounting hole 1310 corresponding to the first mounting hole 1110 and the third mounting hole 1210. In some embodiments, the pole post 50 includes an outer flange 51, a columnar portion 52, and an inner flange 53. The outer flange 51 is located outside the housing 200, and the columnar portion 52 passes through the first mounting hole 1110, the third mounting hole 1210, and the second mounting hole 1310. The outer flange 51 is connected to the end of the columnar portion 52 of the electrode post 50 located outside the housing 200. The inner flange 53 is connected to the end of the columnar portion 52 of the electrode post 50 located inside the housing 200. The inner flange 53 and the end wall 111 together clamp the lower plastic 131, and the outer flange 51 and the end wall 111 together clamp the upper plastic 121. The inner flange 53 of the electrode post 50 contacts the surface of the lower plastic 131 facing the electrode assembly / the surface away from the end wall 111 and fixes the lower plastic 131 to the inner side of the end wall 111 facing the inside of the housing 200. The outer flange 51 of the electrode post 50 contacts the surface of the upper plastic 121 away from the end wall 111 and fixes the lower plastic 131 to the outer side of the end wall 111 away from the inside of the housing 200. The upper plastic 121 and the lower plastic 131 surround the columnar portion 52.

[0036] Now continue to see Figure 4 and Figure 5 , Figure 5 It shows Figure 4An enlarged schematic diagram of region A. A lower groove 1312 is provided on the lower surface of the lower plastic 131 away from the end wall 111. The inner flange 53 is engaged with the lower groove 1312. This engagement is achieved by folding a portion of the inner flange 53 upwards and embedding it into the lower groove 1312. By providing this engaging engagement between the inner flange 53 and the lower plastic 131, the stability and bonding strength of the engagement between them are improved. This strengthens the fit between the terminal post 50 and the housing 200, especially the fit strength between the inner flange 53 of the riveted terminal post 50 and the housing 200, reducing the risk of the terminal post 50 flying out during thermal runaway of the secondary battery 100. Furthermore, in some embodiments, an upper groove 1311 is provided on the upper surface of the lower plastic 131 facing the end wall 111, and a rib 1111 is provided on the end wall 111 to engage with the upper groove 1311. While improving the stability of the fit between the inner flange 53 and the lower plastic 131 through this engagement, the rib 1111 of the housing 200 is further engaged downwards with the upper groove 1311, further enhancing the stability of the fit structure between the electrode post 50 and the housing 200. It can also be understood that, due to the soft properties of the lower plastic 131 material, the rib 1111 of the housing 200 is engaged in the upper groove 1311 on the upper surface of the lower plastic 131. The rigid rib 1111 provides support for the lower plastic 131, reducing the excessive compression of the lower plastic 131 caused by the force exerted during thermal runaway of the secondary battery 100. In some embodiments, the inner flange 53 has a hook-shaped structure 300 with an opening facing the end wall 111. The hook-shaped structure 300 has a tail 301 that engages in the lower slot 1312 and a main body 302 that connects the tail 301 to the post-shaped portion 52. It can be understood that by engaging the hook-shaped tail 301 of the inner flange 53 with the lower slot 1312 to form a fastening, the fit stability between the inner flange 53 and the lower plastic 131 is improved, at least at the main body 302 of the inner flange 53, thereby at least strengthening the fit structure between the pole post 50 and the housing 200. In some embodiments, one end of the end wall 111 facing the pole post 50 is extruded into the housing 200 to form a rib 1111. It can also be understood that the rib 1111 is constructed as an annular structure surrounding the first mounting hole 1110, and the inner hole of the rib 1111 forms part of the first mounting hole 1110. In some embodiments, the width of the rib is in the range of 0.3mm-2mm, and the height of the rib is in the range of 0.3mm-2mm. In some embodiments, the surface of the main body 302 of the inner flange 53 facing the end wall 111 is a recessed surface 55, and the lower plastic 131 has a protrusion 1313 that mates with the recessed surface 55, further strengthening the convex-concave fit between the inner flange 53 and the lower plastic 131. It can be understood that... Figure 4 and Figure 5An embodiment of a secondary battery 100 shown strengthens the fit between the terminal post 50 and the housing 200, at least more so at the main body portion 302 where the tail portion 301 and the columnar portion 52 are connected.

[0037] Figure 6 A half-sectional perspective view of a lower plastic 131 according to an embodiment of this application is shown. See also Figure 6 The lower plastic 131 has a second mounting hole 1310, an upper slot 1311 and a lower slot 1312. Before the lower plastic 131 is assembled with the housing 200 and the pole post 50, the upper slot 1311 and the lower slot 1312 are provided on the lower plastic 131 to accommodate the rib 1111 of the housing 200 and the tail 301 of the inner flange 53 that will be bent into the lower slot 1312.

[0038] Figure 7 A partial cross-sectional schematic diagram of a secondary battery according to another embodiment of this application is shown. Figure 8 It shows Figure 7 A magnified view of region B in the middle. See also... Figure 7 and Figure 8 In some embodiments, the tail 301 of the inner flange 53 is a second bent portion 304 extending towards the lower slot 1312. The second bent portion 304 engages with the lower slot 1312 to form a latching connection between the inner flange 53 and the lower slot 1312. This improves the stability of the fit between the inner flange 53 and the lower plastic 131, at least at the tail 301, thereby strengthening the fit structure between the pole post 50 and the housing 200. The formation process of the second bent portion 304 will be discussed later. Figure 9-11 As described in the text. In some embodiments, the rib 1111 is spaced apart from the first mounting hole 1110 along the radial direction of the first mounting hole 1110. It can also be understood that in some embodiments, the rib 1111 is an annular structure surrounding the first mounting hole 1110, the inner diameter of the rib 1111 is larger than the diameter of the first mounting hole 1110, and it is not formed as part of the first mounting hole 1110. In some embodiments, the inner diameter of the rib 1111 is coaxial with the first mounting hole 1110. It can be understood that... Figure 7 and Figure 8 In one embodiment of the secondary battery 100 shown, the fit between the terminal 50 and the housing 200 is strengthened at least more at the tail 301 of the inner flange 53. In some embodiments, the height H1 of the second bend is greater than 0.3 mm, and the width H2 of the second bend is greater than 0.3 mm. It is understood that the second bend 304 within this numerical range is more conducive to forming.

[0039] Figures 9-11 A partial cross-sectional schematic diagram of the assembly process of a secondary battery according to another embodiment of this application is shown. See also Figure 9The electrode post 50 is not yet fully engaged with the end wall 111 and the lower plastic 131. A portion of the columnar portion 52 of the electrode post 50 has not yet been folded down to form the inner flange 53. The rib 1111 is already engaged with the upper slot 1311. See also Figure 10 A portion of the columnar portion 52 of the pole post 50 is folded over to form an inner flange 53. The tail portion 301 of the inner flange 53 has not yet been engaged with the lower slot 1312 of the lower plastic 131 to form a second bent portion 304. See also Figure 11 The tail 301 of the inner flange 53 is folded upward to form a second bent portion 304 that engages with the lower slot 1312. This is understandable. Figures 9-11 The assembly process of the secondary battery 100 shown has been improved by adding a step to the original riveting process of the terminal post 50, the housing 200 and the lower plastic 131. That is, by using the contouring tooling of the lower plastic 131 and the inner flange 53, the tail 301 of the inner flange 53 is folded upward and fixed together with the lower plastic 131.

[0040] Embodiments of this application also provide an electronic device 1000, which includes a secondary battery 100 as described above, and the electronic device 1000 can have the beneficial effects described above with respect to the secondary battery 100.

[0041] 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 secondary battery, characterized in that, include: The housing includes an end wall having a first mounting hole; The lower plastic part contacts the lower surface of the end wall facing the interior of the housing, and the lower plastic part has a second mounting hole corresponding to the first mounting hole; The pole post includes a columnar portion and an inner flange. The columnar portion passes through the first mounting hole and the second mounting hole. The inner flange is connected to one end of the columnar portion located inside the housing and together with the end wall clamps the lower plastic. The lower surface of the lower plastic part facing away from the end wall is provided with a lower retaining groove, and the inner flange is fastened to the lower retaining groove.

2. The secondary battery according to claim 1, characterized in that, The lower plastic has an upper groove on its upper surface facing the end wall, and the end wall has a protruding rib that engages with the upper groove.

3. The secondary battery according to claim 1, characterized in that, The inner flange has a hook-shaped structure with an opening facing the end wall. The hook-shaped structure has a tail and a main body that connects the tail to the columnar portion, wherein the tail engages with the lower slot to form the fastening.

4. The secondary battery according to claim 2, characterized in that, The end of the end wall facing the pole is extruded into the housing to form the rib.

5. The secondary battery according to claim 3, characterized in that, The surface of the main body portion of the inner flange facing the end wall is a concave surface, and the lower plastic has a protrusion that mates with the concave surface.

6. The secondary battery according to claim 1, characterized in that, The tail of the inner flange is a second bent portion that bends and extends toward the lower slot, and the second bent portion is inserted into the lower slot to form the fastening.

7. The secondary battery according to claim 2, characterized in that, Along the radial direction of the first mounting hole, the rib is spaced apart from the first mounting hole.

8. The secondary battery according to claim 6, characterized in that, The height H1 of the second bend is greater than 0.3 mm, and the width H2 of the second bend is greater than 0.3 mm.

9. The secondary battery according to claim 2, characterized in that, The width of the rib is in the range of 0.3mm-2mm, and the height of the rib is in the range of 0.3mm-2mm.

10. An electronic device, characterized in that, Includes the secondary battery as described in any one of claims 1-9.

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