Secondary battery, battery pack, and electronic device

Abstract

The utility model provides a secondary battery, comprising: a housing comprising an end wall and a side wall surrounding the end wall, the end wall having a first assembly hole; the lower plastic is in contact with the 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 plastic is provided with a penetrating channel penetrating through the lower plastic in the thickness direction of the lower plastic. The utility model aims to provide a secondary battery, a battery pack and an electronic device so as to at least improve the safety of the secondary battery.

Description

Technical Field

[0001] The utility model relates to a secondary battery, a battery pack and an electronic device. Background Art

[0002] In the field of new energy power batteries, secondary batteries generally include an electrode assembly, a casing, and a cover plate. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator located between the positive and negative electrode sheets. These positive and negative electrode sheets and separator are stacked and wound together to form an electrode assembly, which is then encapsulated in a casing. Typically, a lower plastic is located between the electrode assembly and the end wall of the casing to prevent the electrode assembly from moving and provide insulation. Utility Model Content

[0003] In view of the problems existing in the related art, the purpose of the present invention is to provide a secondary battery, a battery pack and an electronic device, so as to at least improve the safety of the secondary battery.

[0004] To achieve the above-mentioned objectives, the present invention provides a secondary battery, comprising: a housing, comprising an end wall and a side wall surrounding the end wall, the end wall having a first assembly hole; a lower plastic, contacting a surface of the end wall facing the interior of the housing, the lower plastic having a second assembly hole corresponding to the first assembly hole; a pole, comprising a columnar portion and an inner flange, the columnar portion passing through the first assembly hole and the second assembly hole, the inner flange being connected to an end of the columnar portion located inside the housing and jointly clamping the lower plastic with the end wall; wherein, along the thickness direction of the lower plastic, the lower plastic is provided with a through-channel extending through it.

[0005] In some embodiments, a surface of the lower plastic facing the end wall includes a recessed portion recessed toward the interior of the housing, and the through channel penetrates the recessed portion.

[0006] In some embodiments, a surface of the lower plastic facing away from the end wall has a reinforcing rib arranged around the second assembly hole, and the through channel is arranged on the reinforcing rib.

[0007] In some embodiments, the through channel includes a plurality of through holes provided on the reinforcing rib, and the lower plastic further includes a non-through glue inlet hole provided on the reinforcing rib, and the distance between the through holes and the glue inlet hole is greater than 0.5 mm.

[0008] In some embodiments, the secondary battery further includes: an electrode assembly, located in the shell, the first pole ear of the electrode assembly facing the plastic downward, wherein the first pole ear includes a plurality of individually bendable conductive sheets, the plurality of conductive sheets are bent toward the axis of the electrode assembly, the through channel is a through hole, the through hole has a first diameter facing the side of the electrode assembly, and a second diameter facing the side of the end wall, the first diameter is smaller than the second diameter, and the first diameter is smaller than the width of any one of the conductive sheets close to the axis of the electrode assembly.

[0009] In some embodiments, the secondary battery further includes: an electrode assembly and a current collecting plate, which are located inside the shell, the current collecting plate being located between the electrode assembly and the lower plastic, the current collecting plate connecting the pole and the first pole ear of the electrode assembly, the current collecting plate having a weight-reducing hole, projected along the thickness direction of the lower plastic, and the through channel of the lower plastic being staggered with the weight-reducing hole.

[0010] In some embodiments, a surface of the lower plastic facing away from the end wall includes a first reinforcing rib surrounding the second assembly hole, a second reinforcing rib surrounding the first reinforcing rib, and a third reinforcing rib connecting the first reinforcing rib and the second reinforcing rib, and the through channel includes a plurality of grooves that penetrate both the first reinforcing rib and the second reinforcing rib.

[0011] In some embodiments, the secondary battery through-channel includes: a plurality of first through-holes arranged around the second assembly hole; a plurality of second through-holes arranged around the plurality of first through-holes, and the diameters of the first through-holes are different from the diameters of the second through-holes.

[0012] An embodiment of the present application further provides a battery pack comprising any one of the above-mentioned secondary batteries.

[0013] An embodiment of the present application further provides an electronic device including the above-mentioned battery pack.

[0014] The beneficial technical effects of the present utility model are:

[0015] The lower plastic of the embodiment of the present application is provided with a through-channel extending from the top surface to the bottom surface of the lower plastic. When the lower plastic is deformed by the squeeze of the inner flange of the pole and the shell, the through-channel promptly discharges the electrolyte between the lower plastic and the shell, thereby preventing the electrolyte from accumulating between the lower plastic and the shell and causing liquid-phase corrosion, which would lead to blackening or rusting inside the shell, reduce the shell strength, and improve the safety of the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 A perspective view of the lower plastic of the prior art is shown.

[0018] Figure 2 The surface of the lower plastic facing the electrode assembly of the prior art is shown.

[0019] Figure 3 A schematic diagram showing an electronic device according to an embodiment of the present application is a vehicle.

[0020] Figure 4 A perspective view of a secondary battery according to an embodiment of the present application is shown.

[0021] Figure 5 A top view of a secondary battery is shown.

[0022] Figure 6 Shown along Figure 5 Cross-sectional view taken along line AA.

[0023] Figure 7 and Figure 8 Shown Figure 6 An enlarged view of the portion on the side where the center pole is located.

[0024] Figure 9 One side of the top surface of the lower plastic according to the first embodiment of the present application is shown.

[0025] Figure 10 Shown along Figure 9 Cross-sectional view taken along line BB.

[0026] Figure 11 One side of the bottom surface of the lower plastic according to the first embodiment of the present application is shown.

[0027] Figure 12 One side of the top surface of the lower plastic according to the second embodiment of the present application is shown.

[0028] Figure 13 Shown along Figure 12 Cross-sectional view taken along line CC.

[0029] Figure 14 One side of the bottom surface of the lower plastic according to the second embodiment of the present application is shown.

[0030] Figure 15 One side of the top surface of the lower plastic according to the third embodiment of the present application is shown.

[0031] Figure 16 Shown along Figure 15 Cross-sectional view taken along line DD.

[0032] Figure 17 Shown Figure 15 Magnified view of area E in the middle.

[0033] Figure 18 One side of the bottom surface of the lower plastic according to the third embodiment of the present application is shown.

[0034] Figure 19 Shown Figure 18 Magnified view of region F.

[0035] Figure 20 One side of the top surface of the lower plastic according to the fourth embodiment of the present application is shown.

[0036] Figure 21 One side of the bottom surface of the lower plastic according to the fourth embodiment of the present application is shown.

[0037] Figure 22 A current collecting plate according to an embodiment of the present application is shown.

[0038] Figure 23 A partially unfolded first tab according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0039] In order to better understand the spirit of the embodiments of the present application, some preferred embodiments of the present application are further described below.

[0040] The embodiments of the present application will be described in detail below. Throughout this specification, identical or similar components and components having identical or similar functions are represented by similar reference numerals. The embodiments described herein with respect to the accompanying drawings are illustrative and diagrammatic and are intended to provide a basic understanding of the present application. The embodiments of the present application should not be construed as limiting the present application.

[0041] As used herein, the terms "substantially," "substantially," and "approximately" are used to describe and illustrate small variations. When used in conjunction with an event or circumstance, the terms may refer to instances where the event or circumstance occurred precisely as well as instances where the event or circumstance occurred very approximately.

[0042] 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 (such as "horizontally", "downwardly", "upwardly", etc.) should be interpreted as referring to the directions described in the discussion or depicted in the drawings. These relative terms are only used for convenience of description and do not require that the present application be constructed or operated in a specific orientation.

[0043] For ease of description, “first,” “second,” “third,” etc. may be used herein to distinguish different components in a figure or a series of figures. “First,” “second,” “third,” etc. are not intended to describe the corresponding components.

[0044] Figure 1A perspective view of the lower plastic 1 in the prior art is shown, wherein the surface thereof facing the housing (the material is generally steel) is shown, and this surface is a plane. Figure 2 The figure shows the surface of the lower plastic 1 facing the electrode assembly (JR) in the prior art. The assembly process of the secondary battery includes: placing the lower plastic 1 in the shell, then assembling the pole (usually made of aluminum) to the lower plastic 1 and the shell, and then clamping the lower plastic 1 to the shell by riveting the pole. During the riveting process, the pole will squeeze the lower plastic 1 in the radial direction, causing the edge of the lower plastic 1 to abut the shell. In other words, the center of the lower plastic 1 is subjected to a radial outward force, and the edge of the lower plastic 1 is subjected to a radial inward force, causing part of the lower plastic 1 to produce a downward concave deformation. The lower plastic 1 is a solid sheet. A cavity for electrolyte accumulation is easily formed at the deformed position. During the injection process, the secondary battery is placed with the pole facing downward, and the injection is performed from the end of the secondary battery opposite to the pole. At this time, the lower plastic 1 is located at the bottom of the shell, and the electrolyte will penetrate between the lower plastic 1 and the shell, causing corrosion to the shell due to electrolyte accumulation. Due to the deformed depression of the lower plastic 1, more electrolyte accumulates between the lower plastic 1 and the shell. After the secondary battery is circulated for a period of time, concentrated liquid phase corrosion of the shell will occur.

[0045] The present invention provides an electronic device 1000. For the convenience of description, the following embodiments are described by taking the electronic device 1000 as a vehicle as an example. Figure 3The vehicle is equipped with a battery pack 1002 inside. Battery pack 1002 can be located at the bottom, front, or rear of the vehicle body 1001. Battery pack 1002 can be used to power the vehicle, for example, as the vehicle's operating power source. The working portion of the electronic device 1000 is electrically connected to battery pack 1002 to obtain electrical energy. The vehicle can be a fuel-powered vehicle, a gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, among others, but is not limited thereto. The working portion is the vehicle body, with battery pack 1002 located at the bottom of the vehicle body and providing electrical energy for the vehicle's operation and for the operation of its electrical components. However, in other embodiments, the electronic device 1000 can also be a mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, or electric tool, among others. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, among others. The working portion can draw electrical energy from battery pack 1002 and perform corresponding operations, such as the blade rotation unit of a fan or the dust collection unit of a vacuum cleaner. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys; electric tools include metal cutting tools, grinding tools, assembly tools, and railway tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. The present embodiment of the present application does not impose any particular limitation on the electronic device 1000.

[0046] Figure 4 1 shows a perspective view of a secondary battery 100 according to an embodiment of the present application, Figure 5 shows a top view of the secondary battery 100, Figure 6 Shown along Figure 5 The cross-sectional view taken along line AA of FIG. 2 , wherein the electrode assembly and other components in the housing 200 are omitted, and line AA cuts through the third reinforcing rib 342, so Figure 6 The through channel 35 on the lower plastic 30 is not shown. Figure 7 and Figure 8 Shown Figure 6 An enlarged view of the portion on the side where the middle pole 50 is located, wherein Figure 8The figure shows a schematic diagram of the lower plastic 30 being deformed due to the squeezing of the pole 50 and the shell 200. The embodiment of the present application provides a secondary battery 100, which includes a shell 200, a lower plastic 30 located in the shell 200, an electrode assembly, a current collecting plate 150, and a pole 50 assembled on the shell 200 and the lower plastic 30. The shell 200 includes an end wall 111 and a side wall 112 surrounding the end wall 111, and the end wall 111 has a first assembly hole 1110; the lower plastic 30 is in contact with the surface of the end wall 111 facing the interior of the shell 200, and the lower plastic has a second assembly hole 300 corresponding to the first assembly hole 1110; the pole 50 includes an outer flange 53, a columnar portion 51 and an inner flange 52, the outer flange 53 is located outside the shell 200, and the columnar portion 51 passes through the first assembly hole 1110 and the second assembly hole 300. 00, the columnar portion 51 of the pole 50 is connected to the end of the outer flange 53 located outside the shell 200, and the inner flange 52 is connected to the end of the outer flange 53 located inside the shell 200, and the inner flange 52 and the end wall 111 jointly clamp the lower plastic 30. The inner flange 52 of the pole 50 contacts the surface of the lower plastic 30 facing the electrode assembly / the surface away from the end wall 111 (hereinafter referred to as the top surface 31) and fixes the lower plastic 30 to the inner side surface of the end wall 111 facing the interior of the shell 200.

[0047] As long as a stable seal and electrical connection can be established, the connection between the end wall 111 and the side wall 112 can be achieved in a variety of ways, such as integral stamping, integral casting, or separate welding. The shape of the side wall 112 is not limited and can be cylindrical, prismatic, or follow any other closed-loop contour that matches the end wall. The housing 200 defines a cavity for accommodating the electrode assembly, electrolyte, lower plastic 30, current collecting tray 150, and other essential battery components. Specifically, the diameter of the housing 200 can be determined based on the specific dimensions of the electrode assembly. The housing 200 can be made of a variety of materials, such as copper, iron, aluminum, steel, and aluminum alloys. To prevent rusting during long-term use, the housing 200 can be coated with a rust-resistant material, such as nickel. The secondary battery 100 can be a cylindrical battery, such as a 4680 cylindrical battery with a height of 80 mm and a diameter of 46 mm, or a 15 mm height and a 46 mm diameter.

[0048] The electrode assembly is a component 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 laminated electrode assembly, comprising a stacked and / or wound positive electrode sheet, a first separator, a negative electrode sheet, and a second separator. The positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer coated on the positive electrode current collector. A first coated area coated with the positive electrode active material layer and a first uncoated area not coated with the positive electrode active material layer are formed on the positive electrode 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 to the outside of the separator at one end in the height direction of the secondary battery 100, forming a bent positive electrode tab. The negative electrode sheet includes a negative current collector and a negative active material layer coated on the current collector. A second coated region coated with the negative active material layer and a second uncoated region not coated with the negative active material layer are formed on the negative current collector. The second coated region and the second uncoated region are arranged along the height of the electrode assembly. The second uncoated region also extends toward one end of the height of the secondary battery 100, beyond the separator, forming a curved negative electrode tab. A first separator and a second separator are disposed between the positive and negative electrode sheets to separate the positive and negative active material layers. For example, in a lithium-ion secondary battery 100, the positive current collector can be made of aluminum, and the positive active material layer includes a positive active material such as lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative current collector can be made of copper, and the negative active material layer includes a negative active material such as carbon or silicon. The base material of the first and second separators can be polypropylene (PP) or polyethylene (PE). In order to protect and insulate the electrode assembly, an insulating film may be coated on the outside of the electrode assembly. The insulating film may be made of PP, PE, PET, PVC or other high molecular polymer materials.

[0049] Figures 9 to 11 、 Figures 12 to 14 、 Figures 15 to 19 、 Figures 20 to 21 The lower plastic 30 according to the first embodiment to the fourth embodiment of the present application is shown respectively. Figure 22 The collecting plate according to the embodiment of the present application is shown. Figure 23 The first electrode tab 122 of the embodiment of the present application is partially unfolded. The collecting plate 150 is located between the electrode assembly and the lower plastic 30. The collecting plate 150 connects the pole 50 and the first electrode tab 122 of the electrode assembly. The size of the collecting plate 150 can be as follows: Figure 22 As shown, the unit of dimensions other than angles is mm.

[0050] Figure 9 FIG. 1 shows one side of the top surface 31 (facing the electrode assembly) of the lower plastic 30 according to the first embodiment of the present application. Figure 10 Shown along Figure 9 The cross-sectional view taken along line BB is Figure 11 The figure shows the side of the lower plastic 30 facing the end wall 111 and facing away from the electrode assembly (hereinafter referred to as the bottom surface 32) according to the first embodiment of the present application. The lower plastic 30 of the embodiment of the present application is provided with a through-channel 35 that runs through the lower plastic 30 along its thickness (i.e., from the top surface 31 to the bottom surface 32 of the lower plastic 30). When the lower plastic 30 is squeezed and deformed by the inner flange 52 of the terminal 50 and the housing 200, the electrolyte between the lower plastic 30 and the housing 200 is promptly discharged, preventing the electrolyte from accumulating between the lower plastic 30 and the housing 200 and causing concentrated and aggravated corrosion of the housing 200, thereby improving the safety of the secondary battery 100.

[0051] The through-channel 35 can be a through-hole (also called a leakage hole) formed during injection molding, and the through-hole has at least one circumference. For example, the through-channel includes a plurality of first through-holes 351 arranged around the second assembly hole 300, and a plurality of second through-holes 352 arranged around the plurality of first through-holes 351. The diameters of the first through-hole 351 and the second through-hole 352 can be 0.3mm to 5.0mm, preferably 1.0mm to 3.0mm. And the first through-hole 351 and the second through-hole 352 are not limited to the cylindrical shape shown in the figure, and their projected shapes can also be rectangular, runway-shaped, parallelogram or other special shapes. The diameter of the first through-hole 351 and the diameter of the second through-hole 352 can be different. If the diameter of the first through-hole 351 is smaller than the diameter of the second through-hole 352, it can avoid the overall structure of the lower plastic 30 being too weak due to the large hole in the inner circle; on the other hand, the second through-hole 352 will be exposed. Figure 22 The lightening holes 152 of the collecting plate 150 are shown, so the diameter of the second through hole 352 can be smaller. Figure 23A schematic diagram shows the multiple bendable conductive sheets 124 of the first electrode tab 122 unfolded. After the electrode sheets are wound, the multiple conductive sheets 124 are bent toward the axis of the electrode assembly. The diameter of the second through-hole 352 is smaller than the width w of any conductive sheet 124 at one end near the electrode assembly axis to prevent the first electrode tab 122 from extending into the second through-hole 352 and contacting the end wall 111. Therefore, the diameter of the second through-hole 352 can also be smaller than the diameter of the first through-hole 351. In some embodiments, the second through-hole 352 can be configured to avoid the lightening hole 152 and projected along the thickness direction of the lower plastic 30. In other words, when projected from the bottom surface 32 to the top surface 31 of the lower plastic 30, the through-channel 35 of the lower plastic 30 is staggered with the lightening hole 152. In other embodiments, the through hole can be configured such that the diameter of the portion of the top surface 31 exposed to the lightening hole 152 is smaller than the width w, and the diameter of the through hole not exposed to the lightening hole 152 can be slightly larger, for example, larger than the width w, to better discharge the electrolyte between the lower plastic 30 and the end wall 111.

[0052] The lower plastic 30 includes protruding reinforcing ribs 34 on the top surface 31 facing the electrode assembly. The reinforcing ribs 34 may include a first reinforcing rib 341 surrounding the second assembly hole 300, a second reinforcing rib 342 surrounding the first reinforcing rib 341, and a third reinforcing rib 343 connecting the first reinforcing rib 341 and the second reinforcing rib 342. In other words, the lower plastic 30 is thicker where the reinforcing ribs 34 are provided, and thinner in other parts, so that the lower plastic 30 can reduce weight as much as possible while playing an insulating role. The part with the reinforcing ribs 34 is thicker, so the hardness is also greater than that of other parts. When the lower plastic 30 is squeezed by the pole 50 and the outer edge 33 is deformed against the side wall 112, the part with the reinforcing ribs 34 is less likely to deform. The parts on both sides of the reinforcing ribs 34 are thinner and softer. After the lower plastic 30 is deformed, the recessed portion 38 is usually as follows Figure 8 As shown, it is located at the position of the reinforcing rib 34, that is, when the secondary battery 100 is as Figure 6 When placed in the direction shown, the reinforcing rib 34 is at the lowest position, and the bottom surface 32 of the lower plastic 30 at the recessed portion 38 is recessed toward the top surface 31. That is, the surface of the lower plastic 30 at the recessed portion 38 facing the end wall 111 is recessed toward the interior of the housing 200. Setting the through channel 35 to pass through the recessed portion 38 can better drain the electrolyte accumulated between the lower plastic 30 and the end wall 111. Figure 9The first through-hole 351 is provided on the first reinforcing rib 341, and the second through-hole 352 is provided in the area surrounded by the first reinforcing rib 341, the second reinforcing rib 342, and the third reinforcing rib 343. The number of the first through-hole 351 and the second through-hole 352 can be between 1 and 16. In other embodiments, a groove can be actively formed on the bottom surface 32 of the lower plastic 30 during injection molding. In other words, the lower plastic 30 has a recessed portion 38 before being deformed by extrusion, so as to actively concentrate the electrolyte in the recessed portion 38. The through-channel provided in the recessed portion 38 can then be used to drain the electrolyte for better discharge.

[0053] See also Figure 9 A glue hole 306 is provided at the position where the first reinforcing rib 341 connects to the third reinforcing rib 343. The glue hole 306 is a non-through blind hole, and its projection shape can be Figure 9 The circular shape shown can also be rectangular, and the glue hole 309 and the first through-hole 351 do not overlap. The number of glue holes 306 can be four as shown, or three or another number. During injection molding, glue is injected from the location of the glue hole 306. The glue hole 306 is set on the reinforcing rib 34 and is set at the location where the first reinforcing rib 341 connects to the third reinforcing rib 343. This is because during injection, the molten plastic extends from the glue hole 306 to the surrounding area and flows from high to low. The location of the glue hole 306 connects the highest first reinforcing rib 341, second reinforcing rib 342, and third reinforcing rib 343, and does not affect the formation of the reinforcing rib 34. The glue hole 306 is separated from the first through-hole 351, and the distance between the two is greater than 0.5 mm. This is because the injection mold has a protrusion at the location corresponding to the first through-hole 351. If the distance to the glue hole 306 is too close, it will affect the flow of plastic.

[0054] Figure 12 FIG. 1 shows one side of the top surface 31 (facing the electrode assembly) of the lower plastic 30 according to the second embodiment of the present application. Figure 13 Shown along Figure 12 The cross-sectional view taken along the CC line is Figure 14 The second embodiment of the present application shows a side of the bottom surface 32 (facing the end wall 111 ) of the lower plastic 30 . The difference from the first embodiment is that the first through hole 351 is provided between the reinforcing rib 34 and the second assembly hole 300 .

[0055] Figure 15 FIG. 1 shows one side of the top surface 31 (facing the electrode assembly) of the lower plastic 30 according to the third embodiment of the present application. Figure 16 Shown along Figure 15 The cross-sectional view taken along line DD is as follows: Figure 17 Shown Figure 15 The enlarged view of the E area in the middle Figure 18FIG. 1 shows one side of the bottom surface 32 (facing the end wall 111 ) of the lower plastic 30 according to the third embodiment of the present application. Figure 19 Shown Figure 18 An enlarged view of region F in the middle. The first through third embodiments share a common feature: their second through-holes 352 are all located in the "hollowed-out" area surrounded by the first, second, and third reinforcing ribs 341, 342, and 343. Even though this area lacks reinforcing ribs 34, it is completely surrounded by the relatively rigid reinforcing ribs 34, resulting in greater overall strength and less prone to deformation. Therefore, the second through-holes 352 are also located in the recessed portion 38. Providing this area facilitates the drainage of electrolyte between the recessed portion 38 and the end wall 111.

[0056] Compared to the first and second embodiments, the third embodiment differs in that it does not include the first through-hole 351. Another difference is that, while the diameter of the through-holes in the first and second embodiments remains constant, in the third embodiment, the diameter of the second through-hole 352 varies. The first diameter d1 on the top surface 31 side (i.e., the side facing the electrode assembly) is smaller than the second diameter d2 on the bottom surface 32 side (i.e., the side facing the end wall). In other words, the second through-hole 352 is funnel-shaped, enlarging the electrolyte discharge channel between the end wall 111 and the lower plastic 30. This makes it easier for the electrolyte to be discharged from between the end wall 111 and the lower plastic 30, facilitating electrolyte circulation.

[0057] The funnel-shaped second through hole 352 is also more convenient for demolding. The protrusion of the injection mold corresponding to the second through hole 352 is a frustum with a larger bottom size and a smaller end size, rather than a cylindrical shape with a uniform diameter. The lower plastic 30 is easier to separate from the injection mold.

[0058] In addition, the first diameter d1 of the second through hole 352 facing the electrode assembly is smaller than Figure 23 The conductive sheet 124 shown has a width w near one end of the electrode assembly axis. The most important function of the lower plastic 30 is insulation. If the first diameter d1 is too large, foreign matter may enter the lower plastic 30, thereby affecting the insulation effect. The first tab 122 is, for example, a positive tab. Figure 22 The collecting plate 150 shown is a positive electrode collecting plate. The collecting plate 150 is provided with four weight-reducing holes 152 for reducing weight. The collecting plate 150 also includes a pole welding portion 154 and a pole tab welding portion 156 located around the pole welding portion. The pole tab welding portion 156 is welded to the first pole tab 122. The top surface 31 of the lower plastic 30 directly faces the collecting plate 150, and directly faces the first pole tab 122 at the position of the weight-reducing holes 152, which is equivalent to partially exposing the first pole tab 122 and not being covered by the collecting plate 150. Figure 23The figure shows the unfolded first tabs 122. The width w of each conductive sheet 124 ranges from 3 mm to 4 mm. The spacing between the first tabs 122 is 0.5 mm. The height of the first tabs 122 is 6.5 ± 0.7 mm. The first tabs 122 are tilted at 15°. During the cycle of the secondary battery 100, the electrode assembly will produce gas, which will bulge outward, causing the portion of the first tab 122 exposed at the lightening hole 152 to warp toward the lower plastic 30. If the first diameter d1 of the second through-hole 352 facing the electrode assembly is larger than the width of the first tab 122, the first tab 122 may penetrate into the second through-hole 352, causing the first tab 122 to contact the negatively charged end wall 111 and short-circuit the secondary battery 100. The first diameter d1 of the second through-hole 352 facing the electrode assembly is smaller than the width w of the conductive sheet 124 at the end near the electrode assembly axis, thereby preventing the above short-circuit.

[0059] In some embodiments, the difference between the first diameter d1 and the second diameter d2 of the funnel-shaped second through-hole 352 ranges from 0.03 mm to 4 mm, such as 0.03 mm to 0.5 mm, 0.2 mm to 4.0 mm, or 1.0 mm to 2.0 mm. Furthermore, the first through-hole 351 and the second through-hole 352 in the first and second embodiments can also be configured as funnel-shaped holes similar to those in the third embodiment.

[0060] Figure 20 FIG. 4 shows one side of the top surface 31 (facing the electrode assembly) of the lower plastic 30 according to the fourth embodiment of the present application. Figure 21 The bottom surface 32 (facing the end wall 111) of the lower plastic 30 according to the fourth embodiment of the present application is shown. In the fourth embodiment, the through-channel 35 includes a plurality of slots that at least partially separate the material of the lower plastic 30, for example, simultaneously penetrating the first reinforcing rib 341 and the second reinforcing rib 342. The slots can extend all the way to the outer edge of the lower plastic 30. The slots can be formed after injection molding, for example, by cutting or shearing the finished lower plastic 30. Compared to the slots in the fourth embodiment, the through-holes in the first to third embodiments reduce the material of the lower plastic 30, further reducing the weight of the lower plastic 30. The slots can also drain the electrolyte between the lower plastic 30 and the end wall 111. The number of slots is not limited to four as shown, and can be any number from 1 to 16. The number of slots can be adjusted according to the size of the secondary battery 100 to achieve better leakage while maintaining insulation. Similar to the first to third embodiments, the grooves can also be set to avoid the weight-reducing holes 152 of the collecting plate 150 to prevent the first pole ear 122 from extending into the grooves and contacting the end wall 111 to cause a short circuit. In other words, the number and position of the grooves can also be adjusted according to the number and position of the weight-reducing holes 152 of the collecting plate 150.

[0061] The lower plastic 30 of the embodiment of the present application is provided with a through channel 35 extending from the top surface 31 to the bottom surface 32 of the lower plastic 30. The through channel 35 can be a through hole or a slot. When the lower plastic 30 is squeezed and deformed by the inner flange 52 of the terminal 50 and the shell 200, the through channel 35 promptly discharges the electrolyte between the lower plastic 30 and the shell 200, thereby preventing the electrolyte from accumulating between the lower plastic 30 and the shell 200 and causing concentrated and aggravated corrosion of the shell 200, thereby improving the safety of the secondary battery 100.

[0062] An embodiment of the present application further provides a battery pack 1002 , including any one of the secondary batteries 100 described above, and the battery pack 1002 can have the beneficial effects described above with respect to the secondary battery 100 .

[0063] An embodiment of the present application further provides an electronic device 1000 , including the battery pack 1002 . The electronic device 1000 can have the beneficial effects described above with respect to the secondary battery 100 and / or the battery pack 1002 .

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A secondary battery, characterized in that: include: The housing comprises an end wall and a side wall surrounding the end wall, wherein the end wall has a first assembly hole; a lower plastic, in contact with a surface of the end wall facing the interior of the housing, the lower plastic having a second assembly hole corresponding to the first assembly hole; The pole comprises a columnar portion and an inner flange, wherein the columnar portion passes through the first assembly hole and the second assembly hole, and the inner flange is connected to one end of the columnar portion located inside the housing and clamps the lower plastic together with the end wall; Wherein, along the thickness direction of the lower plastic, the lower plastic is provided with a through channel penetrating the lower plastic.

2. The secondary battery according to claim 1, wherein The surface of the lower plastic facing the end wall includes a recessed portion recessed toward the interior of the shell, and the through channel penetrates the recessed portion.

3. The secondary battery according to claim 1, wherein The surface of the lower plastic facing away from the end wall has a reinforcing rib arranged around the second assembly hole, and the through channel is arranged on the reinforcing rib.

4. The secondary battery according to claim 3, wherein The through channel includes a plurality of through holes provided on the reinforcing rib, and the lower plastic also includes a non-through glue inlet hole provided on the reinforcing rib, and the distance between the through hole and the glue inlet hole is greater than 0.5 mm.

5. The secondary battery according to claim 1, wherein Also includes: The electrode assembly is located in the shell, and the first tab of the electrode assembly faces the lower plastic, wherein the first tab includes a plurality of individually bendable conductive sheets, and the plurality of conductive sheets are all bent toward the axis of the electrode assembly. The through-channel is a through-hole having a first diameter facing the electrode assembly and a second diameter facing the end wall. The first diameter is smaller than the second diameter, and the first diameter is smaller than the width of any one of the conductive sheets close to the axis of the electrode assembly.

6. The secondary battery according to claim 1, wherein Also includes: The electrode assembly and the current collecting plate are located in the shell. The current collecting plate is located between the electrode assembly and the lower plastic. The current collecting plate connects the pole and the first pole ear of the electrode assembly. The collecting plate has a weight-reducing hole, which is projected along the thickness direction of the lower plastic. The through channel of the lower plastic is staggered with the weight-reducing hole.

7. The secondary battery according to claim 1, wherein The surface of the lower plastic facing away from the end wall has a first reinforcing rib surrounding the second assembly hole, a second reinforcing rib surrounding the first reinforcing rib, and a third reinforcing rib connecting the first reinforcing rib and the second reinforcing rib. The through channel includes a plurality of slots that penetrate the first reinforcing rib and the second reinforcing rib at the same time.

8. The secondary battery according to claim 1, wherein The through passage comprises: A plurality of first through holes are arranged around the second assembly hole; A plurality of second through holes are arranged around the plurality of first through holes, and a diameter of the first through holes is different from a diameter of the second through holes.

9. A battery pack, characterized in that: A secondary battery comprising the secondary battery according to any one of claims 1 to 8.

10. An electronic device, characterized in that: A battery pack comprising the battery pack according to claim 9.

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