Battery cell, battery, and electric device

Abstract

The utility model provides a kind of battery monomer, comprising: shell, the opening is formed in one end of shell;End cover, sealing opening to with shell define containing space;Electrode assembly, is contained in containing space, electrode assembly has first center hole, also has the first pole piece that first center hole's axis is wound, diaphragm and second pole piece, the one end of first pole piece towards end cover has the first lug that is bent and extends towards first center hole, the length of first lug is h;Current collector, it is arranged between electrode assembly and end cover, current collector includes main part and the second center hole in the center of main part, the distance of the welding mark that main part is welded with first lug and axis is c, wherein, the diameter of first center hole is d, the maximum diameter of second center hole is D, d-s2≤D≤d+2*h+2*s1, wherein, 0≤s1≤c-d / 2, 0≤s2≤d / 3, wherein the unit of D, h, c, s1 and s2 is mm.The utility model aims at providing a kind of battery monomer, battery and electric equipment, to at least improve the safety of battery monomer.

Description

Technical Field

[0001] Embodiments of this utility model relate to a battery cell, a battery, and an electrical device. Background Technology

[0002] Due to severe gas generation inside the battery cell, the main exhaust path inside the battery cell is through the central hole area for depressurization. The gas flows towards the end cover side through the central hole area. Excessive gas pressure can easily cause the electrode plates near the central hole of the electrode assembly to move towards the end cover side, which may lead to electrode misalignment or even cause the electrode plates to bulge out of the central hole of the current collector. Utility Model Content

[0003] In view of the problems existing in the related technologies, the purpose of this utility model is to provide a battery cell, a battery and an electrical device to at least improve the safety of the battery cell.

[0004] To achieve the above objectives, this utility model provides

[0005] A battery cell includes: a housing with an opening at one end; an end cap sealing the opening to define an accommodating space with the housing; an electrode assembly housed within the accommodating space, the electrode assembly having a first central hole, and further having a first electrode plate, a separator, and a second electrode plate wound around an axis of the first central hole, the end of the first electrode plate facing the end cap having a first tab bent and extending toward the first central hole, the length of the first tab being h; and a current collector disposed between the electrode assembly and the end cap, the current collector including a main body and a second central hole located at the center of the main body, the distance between the weld mark formed by welding the main body and the first tab and the axis being c, wherein the diameter of the first central hole is d, the maximum diameter of the second central hole is D, d-s2≤D≤d+2×h+2×s1, where 0≤s1≤cd / 2, 0≤s2≤d / 3, and the units of D, h, c, s1, and s2 are all mm.

[0006] In some embodiments, the first electrode includes a current collector and an active material layer disposed on the current collector. The active material layer is disposed on a coated area of ​​the current collector, and an uncoated area of ​​the current collector is disposed at one end of the coated area facing the end cap. The uncoated area includes a transition area connecting the coated area and a first electrode tab extending from the transition area. When d≤D≤d+2×h+2×s1, the first electrode includes a head portion located on the head side and a second portion connected to the head portion along the winding direction. At least a portion of the projection of the head portion along the axial direction is located within the second central hole. The head portion does not have the transition area and the first electrode tab.

[0007] In some embodiments, at least a portion of the second portion of the first electrode tab is bent to cover the coating area of ​​the roll portion and is exposed by the second central hole.

[0008] In some embodiments, the collector plate further includes a shielding portion connected to the main body, the shielding portion shielding the portion of the electrode assembly exposed within the second central hole along the axial direction.

[0009] In some embodiments, the shielding portion is connected to the inner edge of the second central hole. The shielding portion is a plurality of extensions that extend along the plane of the main body and are circumferentially spaced along the second central hole. The plurality of extensions are symmetrically arranged about the axis. The edges of the extensions are connected to the edges of the second central hole. The minimum diameter defined between the edges of the extensions is D1, where d-s2≤D1≤d+2×h+2×s1, and the unit of D1 is mm.

[0010] In some embodiments, the shielding portion is connected to the inner edge of the second central hole, and the shielding portion is a plurality of protrusions that extend toward the electrode assembly relative to the plane of the main body portion and are circumferentially spaced along the second central hole, and the plurality of protrusions are symmetrically arranged about the axis.

[0011] In some embodiments, the protrusion partially covers the inner edge of the first central hole, the extending direction of the protrusion forms an angle with the plane where the main body is located, and the angle is ≥90°.

[0012] In some embodiments, the main body includes a welded portion welded to the first electrode tab and a weak portion with a strength less than the welded portion, the welded portion and the weak portion being alternately arranged around the second central hole, and the shielding portion being projected radially outward along the electrode assembly to coincide with the welded portion and offset from the weak portion.

[0013] Embodiments of this application also provide a battery, including any of the aforementioned secondary batteries.

[0014] Embodiments of this application also provide an electrical device including the battery described above.

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

[0016] The maximum diameter of the second central hole in this embodiment satisfies: d-s2≤D≤d+2×h+2×s1, where 0≤s1≤2c-d, 0≤s2≤d / 3. The exposure range of the easily pulled portion of the control electrode assembly relative to the second central hole of the collector plate is controlled to minimize or completely eliminate exposure of the first electrode tab, thus preventing short circuits even in the event of a pull. 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 embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It is worth noting that, according to industry standard practice, the components are not drawn to scale and are only used for illustrative purposes. In fact, for clarity of discussion, the dimensions of the components can be arbitrarily increased or decreased.

[0018] Figure 1 A front view of a battery cell according to an embodiment of this application is shown.

[0019] Figure 2 It shows along Figure 1 A cross-sectional view of the EE line.

[0020] Figure 3 This is a schematic diagram of the electrode assembly structure of an example of a battery cell in this application.

[0021] Figure 4 A schematic diagram of the first electrode of the electrode assembly according to an embodiment of this application is shown after unfolding.

[0022] Figure 5 A size comparison of the inner boundary, the first center hole, and the second center hole of the header portion according to the first embodiment of this application is shown.

[0023] Figure 6 A size comparison of the inner boundary, the first center hole, and the second center hole of the header portion according to the second embodiment of this application is shown.

[0024] Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 , Figure 13 , Figure 14 Bottom views of the current collectors according to different embodiments of this application are shown.

[0025] Figure 15 It shows Figure 14 A front view of the current collector in the illustrated embodiment.

[0026] Figure 16 It shows Figure 14 Left view of the current collector in the illustrated embodiment.

[0027] Figure 17 A battery according to an embodiment of this application is shown.

[0028] Figure 18 A schematic diagram is shown when the electrical device in an embodiment of this application is a vehicle. Detailed Implementation

[0029] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.

[0030] 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.

[0031] The terms “approximately,” “generally,” “substantial,” “substantial,” “about,” and “approximately” used herein are used to indicate and explain minor variations. For example, when used in conjunction with numerical values, the above terms may refer to a range of variation less than or equal to ±10% of the corresponding numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. As another embodiment, the thickness of a film or layer being “substantially uniform” may refer to the average thickness of the film or layer being less than or equal to ±10% of the standard deviation, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. The term "substantially coplanar" can refer to two surfaces that are within 50 μm along the same plane (such as within 40 μm, 30 μm, 20 μm, 10 μm, or 1 μm along the same plane). If, for example, two components overlap or overlap within 200 μm, 150 μm, 100 μm, 50 μm, 40 μm, 30 μm, 20 μm, 10 μm, or 1 μm, then the two components can be considered "substantially aligned." If the angle between two surfaces or components is, for example, 90° ± 10° (such as ± 5°, ± 4°, ± 3°, ± 2°, ± 1°, ± 0.5°, ± 0.1°, or ± 0.05°), then the two surfaces or components can be considered "substantially perpendicular." When used in conjunction with an event or situation, the terms "approximately," "generally," "substantially," "materially," "about," and "approximately" can refer to the exact occurrence of the event or situation as well as the very close approximation of its occurrence.

[0032] 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.

[0033] 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.

[0034] During the valve opening performance test of a battery cell, it is unfavorable for the electrode assembly to be pulled out (the electrode plates of the electrode assembly are spirally pulled out from the center hole of the current collector) after the explosion-proof valve / pressure relief valve of the battery cell is opened. At the moment the explosion-proof valve opens, the diaphragm between the positive and negative electrode plates may wrinkle or shrink under the action of air pressure. If the electrode plates are pulled out, the positive and negative electrode plates will be misaligned. The positive and negative active materials of adjacent positive and negative electrode plates, the positive active material and the negative current collector (e.g., copper foil), the positive current collector (e.g., aluminum foil) and the negative active material, and the positive and negative current collectors may overlap, leading to a short circuit between the positive and negative electrodes. This can cause thermal runaway of the battery cell, posing a safety risk.

[0035] Figure 1 A front view of a battery cell 100 according to an embodiment of this application is shown. Figure 2 It shows along Figure 1 A cross-sectional view of the EE line.

[0036] Embodiments of this application provide a battery cell 100, which includes a housing 10 and an end cap. The housing 10 has an end wall 14 and a side wall 12. One end of the housing 10 is open, and the end wall 14 is disposed at the other end opposite the opening. The end cap 30 seals the opening of the housing 10 to define a receiving space with the housing 10, and an electrode assembly 20 is received within the receiving space. A current collector 40 is disposed between the electrode assembly 20 and the end cap 30 and electrically connects the electrode assembly 20 and the end cap 30.

[0037] The sidewall 12 surrounds the end wall 14. As long as a stable seal and electrical connection can be formed, the connection between the end wall 14 and the sidewall 12 can be achieved in various ways, such as integral stamping, integral casting, or separate welding. The circumference of the sidewall 12 is not limited; it can be cylindrical (for a cylindrical battery cell 100) or prismatic, or it can surround any other closed-loop contour that matches the end wall 14. In this embodiment, the outer edge of the end wall 14 is circular, and the sidewall 12 is cylindrical, surrounding the outer edge of the end wall 14, with a circular opening formed at the end of the sidewall 12 facing away from the end wall 14. A cavity is formed within the housing 10 formed by the end wall 14 and the sidewall 12 to accommodate the electrode assembly 20, electrolyte, and other necessary battery components. Specifically, the diameter of the housing 10 can be determined according to the specific size of the electrode assembly 20, such as 18mm, 21mm, or 46mm. The shell 10 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent the shell 10 from rusting during long-term use, a layer of anti-rust material such as metallic nickel can be plated on the surface of the shell 10.

[0038] Figure 3 This is a schematic diagram of the electrode assembly 20 structure of an example of a battery cell 100 according to this application. The electrode assembly 20 is disposed inside the housing 10 and is a component in the battery cell 100 where an electrochemical reaction occurs. The housing 10 may contain one or more electrode assemblies 20. The electrode assembly 20 includes electrodes of opposite polarity and a separator 26 spaced between them. The electrodes and the separator 26 are wound to form a wound structure. Specifically, in this embodiment, the electrode assembly 20 includes a first central hole 24 and a first electrode 21, a separator 26, and a second electrode 22 wound around an axis a of the first central hole 24. The first electrode 21 and the second electrode 22 have opposite polarities.

[0039] The first electrode 21 includes a current collector 210 and an active material layer 214 coated on the current collector 210. A coated area 216 with the active material layer 214 and an uncoated area 218 without the active material layer 214 are formed on the current collector 210. The coated area 216 and the uncoated area 218 are arranged along the axial direction A of the housing 10. The uncoated area 218 is located at the end of the coated area 216 facing the end cap 30. The uncoated area 218 includes a transition area 219 connecting the coated area 216 and a first tab 212 extending from the transition area 219. The end of the uncoated area 218 facing the end cap 30 extends beyond the diaphragm 26 and bends towards the axis a of the housing 10 to form stacked first tabs 212. The first electrode 21 is a negative electrode.

[0040] The second electrode 22 includes a second current collector 1211 and a second active material layer coated on the second current collector 1211. A second coated area 1212 coated with the second active material layer and a second uncoated area 1213 uncoated with the second active material layer are formed on the second current collector 1211. The second coated area 1212 and the second uncoated area 1213 are arranged along the axial direction A of the housing 10. One end of the second uncoated area 1213 extends towards the end wall 14 to the outside of the diaphragm 26 and bends towards the axis a of the housing 10 to form a stacked second electrode tab 125. The second electrode 22 is a positive electrode.

[0041] A separator 26 is disposed between the second electrode 22 and the first electrode 21 to isolate the active material layer 214 and the second active material layer. Taking a lithium-ion battery cell 100 as an example, the material of the second current collector 1211 can be aluminum, and the second 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 material of the current collector 210 can be copper, and the active material layer 214 includes a negative electrode active material, which can be carbon or silicon, etc. The substrate material of the separator 26 can be polypropylene (PP) or polyethylene (PE), etc. To protect and insulate the electrode assembly 20, an insulating film can also be wrapped around the electrode assembly 20. The insulating film can be synthesized from PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or other polymer materials.

[0042] Figure 4 A schematic diagram of the first electrode 21 of the electrode assembly 20 according to an embodiment of this application is shown after unfolding. Figure 5 The dimensions of the inner boundary, the first center hole 24, and the second center hole 44 of the head portion 211 formed after winding according to the first embodiment of this application are shown in comparison. Figure 6 The dimensions of the inner boundary, the first center hole 24, and the second center hole 44 of the head portion 211 formed after winding according to the second embodiment of this application are shown in comparison.

[0043] Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 12 , Figure 13 , Figure 14 Bottom views of the collector plate 40 according to different embodiments of this application are shown. Figure 15 It shows Figure 14 A front view of the collector disk 40 in the illustrated embodiment. Figure 16 It shows Figure 14 The illustration shows a left view of the current collector 40 in the embodiment shown. The current collector 40 includes a main body 42 and a second central hole 44 located at the center of the main body 42, which communicates with the first central hole 24. The current collector 40 is a negative current collector. In the prior art, when the explosion-proof valve of the battery cell 100 is opened, the electrode plates of the electrode assembly 20 will be pulled out. The first electrode plate 21 and the second electrode plate 22 near the first central hole 24 will be spirally pulled out from the second central hole 44 in a direction from the positive electrode side (the side where the electrode post is located) to the negative electrode side (the side where the end cap 30 is located) of the battery cell 100. The first electrode plate 21 and the second electrode plate 22 are misaligned, causing the exposed current collector 218 of the first electrode plate 21 to overlap with the second active material layer and / or the second current collector 1211 of the second electrode plate 22, thereby causing a short circuit and thermal runaway of the battery cell 100, which poses a safety risk.

[0044] In the embodiments of this application, the diameter of the first central hole 24 of the electrode assembly 20 is d, and the value of the diameter d of the first central hole 24 is, for example, 6mm-7mm. The maximum diameter of the second central hole 44 of the collector plate 40 is D. See also Figure 4 The uncoated area 218 of the roll head portion 211 on the roll head side of the first electrode 21 cuts off the first electrode tab 212 and cuts off at least a portion of the transition region 219, or completely cuts off the transition region 219. At least a portion of the projection of the roll head portion 211 along the axis a direction is located within the second center hole 44.

[0045] See Figures 3 to 6 After the electrode assembly 20 is wound into a coil, at least a portion of the first tab 212 of the second part connected to the head portion 211 along the winding direction is bent and covers the coating area 216 of the head portion 211 but does not cover the first center hole 24, and is exposed by the second center hole 44. That is to say, Figure 5 and Figure 6 Part of the d~d1 region shown is covered by the first tab 212.

[0046] Figure 5 This is the first embodiment of the present application, wherein d < D ≤ d1, and within the range of d1, such as Figure 3 The uncoated area 218 is completely removed, or as shown... Figure 4 As shown, a portion of the transition region 219 is removed.

[0047] In some embodiments, the diameter d of the first center hole 24 is 7 mm. The diameter of the first center hole 24 depends on the diameter of the winding needle, and 7 mm is an industry standard. The length of the winding head portion 211 is A1, for example, 680 mm. When the diameter d of the first center hole 24 is 7 mm and under a specific winding tightness, according to Archimedes' spiral theorem, the radius of the core portion formed by the winding head portion 211 after winding is 8.5 mm, and the diameter of the core portion formed by the winding head portion 211 after winding is d1. The diameter d1 of the core portion formed by the winding head portion 211 after winding is 17 mm. The length / height h of the first tab 212 (i.e., the distance extending from the bend towards the first center hole 24) is 4.5 mm. This length is designed based on the welding requirements of the first tab 212 and the current collector 40 to ensure the flat stacking, stable welding, and electrical performance requirements of the first tab 212.

[0048] In some embodiments, the radius (d1 / 2) of the core portion formed after the winding of the head portion 211 minus the radius (d / 2) of the first center hole 24 minus the length (h) of the first tab 212 is the distance between the extended end of the innermost first tab 212 and the first center hole 24. This distance is s1, and s1 needs to be greater than or equal to 0 mm. In a preferred embodiment, it is 0.5 mm to 1 mm to ensure that the first tab 212 does not cover the first center hole 24 after folding. That is, s1 = d1 / 2 - d / 2 - h, i.e., d1 = d + 2 × h + 2 × s1, s1 ≥ 0 mm.

[0049] In a preferred embodiment, the radius (8.5 mm) of the core portion formed after the winding of the head portion 211 minus the radius (3.5 mm) of the first center hole 24 minus the height (4.5 mm) of the first tab 212 equals 0.5 mm, so s1 = 0.5 mm.

[0050] When welding the first tab 212 and the weld portion 422 of the current collector 40, the distance c from the weld mark formed by the welding of the first tab 212 and the current collector 40 to the axis a is sufficient. As long as the first tab 212 is present at the weld mark, the (Direct Current Resistance, DCR) requirement is met. That is, the distance c from the extended end of the first tab 212 to the axis a is ≤ c, and the distance s1 from the extended end of the innermost first tab 212 to the first central hole 24 is ≤ cd / 2. In a preferred embodiment, the distance c from the weld mark formed by the welding of the first tab 212 and the current collector 40 to the axis a is 6.5 mm, the diameter d of the first central hole 24 is 7 mm, and the distance s1 from the extended end of the innermost first tab 212 to the first central hole 24 is ≤ 3 mm.

[0051] In summary, in the first embodiment of this application, d < D ≤ d1, i.e., d < D ≤ d + 2 × h + 2 × s1, 0 ≤ s1 ≤ cd / 2. If core pulling occurs, the extraction area of ​​the electrode sheet can be controlled to avoid excessive extraction, thereby reducing the probability of wrinkling and shrinkage of the diaphragm 26 and thus reducing the probability of short circuit.

[0052] See Figure 3 and Figure 4 At least a portion of the first tab 212, which is connected to the second portion of the winding head portion 211 along the winding direction, is bent and covers the coating area 216 of the winding head portion 211 and is exposed by the second center hole 44. In the first embodiment of this application, the bent first tab 212 covers the winding head portion 211 inward to ensure the welding effect with the collector plate 40 and to ensure that the DCR will not increase.

[0053] The first embodiment of this application is within the range of d1, such as... Figure 3 The uncoated area 218 of the roll-up portion 211 is completely removed. That is, when d≤D≤d+2×h+2×s1, the roll-up portion 211 does not have a transition area 219 and a first tab 212, directly removing the exposed current collector 210 within the area of ​​the second central hole 44. The current collector 210 is flush with the active material layer 214. Even if the electrode assembly 20 undergoes localized core pulling, the pulled portion will not have exposed current collector 210, thus preventing a short circuit. Alternatively, within the range of d1 (roll-up portion 211), such as... Figure 4 The height of the transition region 219 in the uncoated area 218 is reduced, thus lowering the height of the exposed current collector 210 in the core-pulled portion even in the event of core pulling, thereby reducing the risk of short circuits. In some embodiments, outside the range d1 (outside the header portion 211), the standard height of the transition region 219 is 1.5 mm with a tolerance of 0.7 mm to 1 mm, i.e., the height of the transition region 219 is 0.8 mm to 2.2 mm; within the range d1 (head portion 211), the standard height of the transition region 219 is 0 mm to 1 mm with a tolerance of 0.7 mm, i.e., when the standard height is 1 mm, the height of the transition region 219 is 0.3 mm to 1.7 mm, and the height of the transition region 219 in the header portion 211 is reduced by at least 0.5 mm.

[0054] In the first embodiment of this application, d < D ≤ d1, which controls the core-pulling range of the electrode assembly 20 and avoids the current collector 210 exposed within the core-pulling range from overlapping with the active material of the misaligned second electrode 22 or the end of the second coating area 1212 facing the end cap 30 after core-pulling, which would cause a short circuit and thermal runaway. This greatly improves the safety performance of the battery cell 100 and has no impact on the energy density of the battery cell 100.

[0055] Figure 6This is the second embodiment of the present application, wherein D ≤ d, and the second central hole 44 of the current collector 40 is at least aligned with the first central hole 24 of the electrode assembly 20, or is smaller than the first central hole 24. By setting a second central hole 44 equivalent to the first central hole 24, the electrode assembly 20 can be prevented from pulling out of the core as much as possible, directly avoiding the occurrence of core pulling, or controlling the range of core pulling as much as possible. Of course, D cannot be too small, as this will affect the injection of electrolyte, or when performing a needle penetration test on the housing of the battery cell 100, the heat dissipation path will be blocked due to the second central hole 44 being too small, resulting in probabilistic failure. In some embodiments, d-s2 ≤ D ≤ d, 0 ≤ s2 ≤ d / 3. In a preferred embodiment, the diameter of the first central hole 24 is d = 6 mm, and s2 = 1 mm. The second embodiment of the present application avoids the occurrence of core pulling or controls the range of core pulling as much as possible by designing and controlling the diameter of the second central hole 44 of the current collector 40. It retains the gas generation and heat release channels of the electrode assembly 20, and avoids thermal runaway caused by the core being pulled out of the electrode assembly 20 after the valve of the battery cell 100 is opened, thus greatly improving the safety performance of the battery cell 100.

[0056] In summary, the maximum diameter D of the second central hole 44 in this embodiment satisfies: d-s2≤D≤d+2×h+2×s1, where 0≤s1≤2c-d, 0≤s2≤d / 3. Based on this, the maximum range of D is dd / 3≤D≤d+2×h+2×(2c-d). While meeting the gas generation requirements of the electrode assembly 20 and the stable welding requirements between the manifold 40 and the first electrode tab 212, the core-pulling range of the electrode assembly 20 is controlled to minimize or completely expose the first electrode tab 212. Even if core-pulling occurs, short circuits are less likely to occur.

[0057] See Figures 7 to 11 , Figures 14 to 16 In the first or second embodiment, the collector plate 40 further includes a shielding portion (extension 46 / protrusion 47) connected to the main body portion 42. The shielding portion shields the portion of the electrode assembly 20 exposed within the second central hole 44 along the direction of axis a. Embodiments of this application ensure the flatness of the central region by providing a shielding portion in the central region of the electrode assembly 20 (the portion exposed within the second central hole 44) where core pulling is likely to occur. The shielding portion can be any protruding structure connected to the main body portion that can reduce the size of the second central hole 44, further preventing core pulling of the electrode assembly 20.

[0058] See Figures 7 to 11The shielding portion is the inner edge connected to the second central hole 44. The shielding portion consists of a plurality of extensions 46 extending along the plane of the main body portion 42 and spaced circumferentially along the second central hole 44. The plurality of extensions 46 are symmetrically arranged about axis a. The plurality of extensions 46 extend in the horizontal direction (perpendicular to axis a) to shield the end face of the electrode assembly 20, prevent the electrode assembly 20 from being pulled out, and ensure the pressure relief of the first central hole 24 and the second central hole 44.

[0059] The edge of the extension 46 connects to the edge of the second central hole 44. The minimum diameter defined between the edges of the extension 46 is D1 (in mm), where d-s2≤D1≤d+2×h+2×s1, and 0≤s1≤2c-d, 0≤s2≤d / 3. The minimum diameter D1 limits the protrusion size of the extension 46, ensuring the pressure relief effect of the first central hole 24 and the second central hole 44, and preventing failure during the needle penetration test.

[0060] Figure 7 In the first embodiment, the maximum diameter D of the second central hole 44 is 12 mm and the minimum diameter D1 is 6 mm. The collector plate 40 includes four extensions 46, and the extensions 46 are fan-shaped structures with a radius R1 of 3 mm.

[0061] Figure 8 In the first embodiment, the maximum diameter D of the second central hole 44 is 12 mm and the minimum diameter D1 is 6 mm. The collector plate 40 includes two extensions 46, which are fan-shaped structures with a radius R1 of 3 mm.

[0062] Figure 9 In the first embodiment, the maximum diameter D of the second central hole 44 is 12 mm and the minimum diameter D1 is 6 mm. The collector plate 40 includes two extensions 46, which are triangular in structure.

[0063] Figure 10 In the first embodiment, the maximum diameter D of the second central hole 44 is 12 mm and the minimum diameter D1 is 6 mm. The collector plate 40 includes two extensions 46, which are rectangular structures with a width W of 2 mm.

[0064] Figure 11 In the first embodiment, the maximum diameter D of the second central hole 44 is 7mm, and the collector plate 40 does not include the extension 46.

[0065] Figure 12 In the second embodiment, the maximum diameter D of the second central hole 44 is 6 mm, and the collector plate 40 does not include the extension 46.

[0066] Figures 14 to 16In the second embodiment, with the second central hole 44 perfectly aligned with the first central hole 24, a shielding portion is connected to the inner edge of the second central hole 44. The shielding portion consists of multiple protrusions 47 extending relative to the plane of the main body 42 towards the electrode assembly 20 and spaced circumferentially along the second central hole 44. These protrusions 47 are symmetrically arranged about axis a. The protrusions 47 extend into the first central hole 24, partially shielding its edge. While shielding the electrode assembly 20 from core pulling, they also help to position the current collector 40 relative to the first central hole 24, improving the stability of the current collector 40 and preventing deviations in the welding position between the current collector 40 and the first tab 212, which would affect the welding quality and the stability of the electrical performance of the battery cell 100. The protrusions 47 partially shield the inner edge of the first central hole 24. The protrusion 47 does not completely block the inner edge of the first central hole 24, and its large area will not significantly increase the strength of the collector plate 40 at the second central hole 44. This avoids affecting the tearing of the collector plate 40 when the valve is opened, ensuring the elasticity and pressure relief of the collector plate 40, and preventing damage to the electrode assembly 20 or obstruction of pressure relief. In some embodiments, a single protrusion 47 blocks the inner edge of the first central hole 24 within an angle β of 50°, and the height i of the protrusion 47 in the axial direction A is 3.5 mm.

[0067] See Figure 15 The extending direction of the protrusion 47 forms an angle α with the plane containing the main body 42, and the angle α ≥ 90°. When the protrusion 47 extends into the first central hole 24, the distance between the ends of the protrusion 47 is not greater than the distance between the roots, making the positioning of the protrusion 47 and the first central hole 24 easier and avoiding damage to the electrode assembly 20. See also Figure 16 The end of the protrusion 47 has a fan-shaped shape with a radius R2 of 1 mm, instead of a sharp corner shape, to further avoid damage to the electrode assembly 20.

[0068] The outer side of the protrusion 47 facing the second central hole 44 abuts against the inner wall of the first central hole 24. Precise positioning with the first central hole 24 increases the contact area between the protrusion 47 and the inner wall of the first central hole 24, providing resistance to the first central hole 24 when the valve is opened to release pressure, stabilizing and blocking the electrode plates of the electrode assembly 20, and preventing core pulling.

[0069] See Figures 7 to 11 , Figures 14 to 16The main body 42 includes a welded portion 422 welded to the first electrode tab 212, and a weak portion 424 with less strength than the welded portion 422 (less strong than the welded portion 422, for example, thinner or directly a through hole, to facilitate tearing when the valve is opened). The welded portion 422 and the weak portion 424 are alternately arranged around the second central hole 44. The projection of the shielding portion outward along the radial R of the electrode assembly 20 coincides with the welded portion 422 and is offset from the weak portion 424. This prevents the presence of the shielding portion from affecting the tearing and folding of the manifold 40 when the valve is opened, ensuring the pressure relief effect.

[0070] See Figure 17 This application also provides a battery 300, which includes the aforementioned battery cells 100. In one embodiment of the battery 300, the battery 300 includes a housing 101, a cover 102, and multiple battery cells 100. The multiple battery cells 100 are placed in the housing 101 and are connected in series or parallel, or a combination of series and parallel connections. The cover 102 seals the housing 101 to protect the multiple battery cells 100. It should be noted that the battery 300 may also include a battery thermal management system, circuit board, etc., in addition to the battery cells 100. The battery 300 may be a battery module, a battery pack, an energy storage cabinet, etc.; these will not be described in detail here.

[0071] See Figure 18 This application also provides an electrical device 1000, which includes the aforementioned battery 300. The working part of the electrical device 1000 is connected to the battery 300 to obtain electrical power. As an example, the electrical 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 battery 300 is, for example, located at the bottom of the vehicle 1001 and provides electrical power for the vehicle's operation or the operation of electrical components within the vehicle. However, in other embodiments, the electrical device 1000 can also be a mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, and power tool, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; the working part can be a unit component capable of obtaining electrical power from the battery 300 and performing corresponding work, such as a fan blade rotation unit or a vacuum cleaner suction unit. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the aforementioned electrical device 1000.

[0072] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A battery cell, characterized in that, include: A housing, wherein one end of the housing is formed with an opening; End cap, sealing the opening to define an accommodating space with the housing; An electrode assembly is housed within the receiving space. The electrode assembly has a first central hole and also has a first electrode plate, a diaphragm, and a second electrode plate wound around the axis of the first central hole. The end of the first electrode plate facing the end cap has a first electrode tab that is bent and extends toward the first central hole. The length of the first electrode tab is h. A current collector is disposed between the electrode assembly and the end cap. The current collector includes a main body and a second central hole located at the center of the main body. The distance between the weld mark formed by welding the main body to the first electrode tab and the axis is c. Wherein, the diameter of the first central hole is d, the maximum diameter of the second central hole is D, d-s2≤D≤d+2×h+2×s1, where 0≤s1≤cd / 2, 0≤s2≤d / 3, and the units of D, h, c, s1 and s2 are all mm.

2. The battery cell according to claim 1, characterized in that, The first electrode includes a current collector and an active material layer disposed on the current collector. The active material layer is disposed on a coated area of ​​the current collector. An uncoated area of ​​the current collector is disposed at one end of the coated area facing the end cap. The uncoated area includes a transition area connecting the coated area and a first electrode tab extending from the transition area. When d≤D≤d+2×h+2×s1, the first electrode includes a head portion located on the head side and a second portion connected to the head portion along the winding direction, and at least a portion of the projection of the head portion along the axial direction is located in the second central hole. The beginning portion of the scroll does not have the transition area and the first tab.

3. The battery cell according to claim 2, characterized in that, At least a portion of the second portion of the first electrode tab is bent to cover the coating area of ​​the roll portion and is exposed by the second central hole.

4. The battery cell according to claim 1 or 2, characterized in that, The collector plate also includes a shielding portion connected to the main body, which shields the portion of the electrode assembly exposed in the second central hole along the axial direction.

5. The battery cell according to claim 4, characterized in that, The shielding portion is connected to the inner edge of the second central hole. The shielding portion is a plurality of extensions that extend along the plane of the main body and are circumferentially spaced along the second central hole. The plurality of extensions are symmetrically arranged about the axis. The edge of the extension is connected to the edge of the second central hole, and the minimum diameter defined between the edges of the extension is D1, where d-s2≤D1≤d+2×h+2×s1, and the unit of D1 is mm.

6. The battery cell according to claim 4, characterized in that, The shielding portion is connected to the inner edge of the second central hole. The shielding portion is a plurality of protrusions that extend toward the electrode assembly relative to the plane of the main body portion and are circumferentially spaced along the second central hole. The plurality of protrusions are symmetrically arranged about the axis.

7. The battery cell according to claim 6, characterized in that, The protrusion partially obscures the inner edge of the first central hole. The extension direction of the protrusion forms an angle with the plane of the main body, and the angle is ≥90°.

8. The battery cell according to claim 4, characterized in that, The main body includes a welded portion welded to the first electrode tab and a weak portion with a strength less than the welded portion. The welded portion and the weak portion are alternately arranged around the second central hole. The projection of the shielding portion along the radial outward of the electrode assembly coincides with the welded portion and is offset from the weak portion.

9. A battery, characterized in that, Includes the battery cell according to any one of claims 1 to 8.

10. An electrical appliance, characterized in that, Includes the battery as described in claim 9.

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