Battery cell, battery pack, and electric device

Abstract

The application provides a battery monomer, a battery pack and a power utilization device. The battery monomer comprises: a shell assembly comprising a shell and a cover plate, one end of the shell is provided with an opening, the cover plate covers the opening to define a containing cavity, and the cover plate is provided with an explosion-proof valve; an electrode assembly located in the containing cavity; a current collector disc located between the electrode assembly and the cover plate; wherein the current collector disc comprises a disc surface part and a fixed pin, the fixed pin is fixedly connected and electrically connected with the shell assembly, the disc surface part is provided with a center hole and exhaust holes, the exhaust holes are distributed along the circumference of the current collector disc at intervals, welding zones are formed between adjacent exhaust holes, the disc surface part is provided with a folding line matched with the position of the explosion-proof valve, the disc surface part is provided with a folding guide part along the folding line, and the material strength of the folding guide part is less than that of the welding zone. The above technical scheme can at least reduce the difficulty of folding and opening the current collector disc, thereby improving the safety and reliability of the battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery cell, a battery pack, and an electrical device. Background Technology

[0002] Cylindrical batteries are a common type of battery, widely used in mobile devices, power tools, and electric vehicles due to their advantages in energy density, power output, and reliability. The current collector is a crucial structural component of a cylindrical battery, primarily serving functions such as current transmission, mechanical support, and venting. In the design of individual battery cells, the openings in the current collector are designed to facilitate the smooth expulsion of gases and active materials, effectively reducing the risk of pressure buildup and lowering the possibility of battery explosion or casing rupture. However, existing current collectors still have some significant shortcomings in practical applications. Utility Model Content

[0003] In view of the problems existing in the related technologies, the purpose of this application is to provide a battery cell, battery pack and electrical equipment that can optimize the structure of the current collector, effectively reduce the difficulty of flipping and opening it after thermal runaway, thereby improving the safety and reliability of the battery.

[0004] According to one aspect of the embodiments of this application, a battery cell is provided, the battery cell comprising: a housing assembly including a housing and a cover plate, one end of the housing having an opening, the cover plate covering the opening to define a receiving cavity, the cover plate having an explosion-proof valve; an electrode assembly located within the receiving cavity; and a current collector located between the electrode assembly and the cover plate; wherein the current collector includes a disk surface and fixed pins connecting the disk surface, the fixed pins being fixedly connected to and electrically connected to the housing assembly, the disk surface having a central hole and vent holes, the vent holes being spaced apart circumferentially along the current collector, a welding area being formed between adjacent vent holes, the disk surface having a fold line matching the position of the explosion-proof valve, the disk surface having a flipping guide portion arranged along the fold line, the material strength of the flipping guide portion being less than the material strength of the welding area.

[0005] In some embodiments, the flipping guide is a through or non-through opening along the thickness direction of the disk surface; the opening is disposed on opposite sides of the vent hole along the circumferential direction and communicates with the vent hole; the openings are distributed on opposite sides of the welding area along the circumferential direction and do not interfere with each other.

[0006] In some embodiments, the welding area has weld marks formed by welding the disk surface to the electrode assembly. In the radial direction of the collector disk, the weld marks are continuous and cross the fold line, or in the radial direction of the collector disk, the weld marks are discontinuous and distributed on opposite sides of the fold line.

[0007] In some embodiments, the flipping guide portion of the disk surface is a thinned portion provided along the fold line, and the thinned portions are continuous or spaced apart along the fold line.

[0008] In some embodiments, the thickness of the disc face is the same on both sides of the upset portion.

[0009] In some embodiments, along the circumferential direction of the fold line, the circumferential length of each opening is H, the circumferential length of the disk surface is C, the total circumferential length of the disk surface between adjacent openings is L1, the total circumferential length of each opening and the connected vent is L2, and the total circumferential length of the welding area is L3, where L1 = C - L2, L1 ≥ L3 + H × n, n is the number of openings, and the value of H ranges from 1 mm to 1.5 mm.

[0010] In some embodiments, the opening is rectangular or racetrack-shaped; or, the opening is triangular, with one side of the triangle connected to the vent, and the other two sides of the triangle forming a sharp angle extending away from the vent.

[0011] In some embodiments, the flip guide portion of the disk surface is a plurality of openings spaced apart along the fold line.

[0012] According to another aspect of the embodiments of this application, a battery pack is provided, which includes the battery cells described above.

[0013] According to another aspect of the embodiments of this application, an electrical device is provided, which includes a battery pack, the battery pack including the aforementioned battery cells.

[0014] The beneficial effects of this application include:

[0015] By setting a flipping guide along the flipping line of the current collector, the flipping force required to open the current collector can be reduced, thereby ensuring that the current collector can flip open more smoothly after thermal runaway, effectively promoting the discharge of gas and active materials, reducing the risk of pressure accumulation, and thus improving the safety and reliability of the battery. 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 perspective view of a battery cell according to some embodiments is shown.

[0018] Figure 2A schematic cross-sectional view of a vertical section of a battery cell according to an embodiment of this application is shown.

[0019] Figure 3 A plan view of a manifold according to an embodiment of this application is shown.

[0020] Figures 4A to 4B as well as Figures 5A to 5B Plan view diagrams of the manifolds according to other embodiments of this application are shown respectively.

[0021] Figure 6 A plan view of the collector disk for comparison is shown.

[0022] Figure 7 The curves showing the relationship between the folding force and folding displacement of the comparative collector disk and the collector disk of the embodiment of this application are presented.

[0023] Figure 8 A schematic diagram is shown when the electrical equipment according to an embodiment of this application is a vehicle. Detailed Implementation

[0024] To better understand the spirit of the embodiments of this application, the following description is based on some preferred embodiments of this application.

[0025] 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.

[0026] 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, the 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.

[0027] 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.

[0028] 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.

[0029] When a cylindrical battery experiences thermal runaway, the internal pressure generated by the thermal runaway in different parts of the current collector (such as the negative current collector) is uneven. For example, in some cases, the starting point of thermal runaway is located in a localized area of ​​the battery; in others, the forces acting between the various internal structures differ. These factors can lead to uneven internal pressure at different locations on the current collector, resulting in the current collector failing to fully open or only partially opening. This situation is also related to factors such as the uniformity of the current collector's strength at different locations and the flatness of its surface. Such uneven pressure hinders the effective discharge of active materials from the battery, potentially leading to serious failures such as battery explosion or casing rupture.

[0030] While existing technologies consider the necessity of gas release when designing current collectors, their actual performance under thermal runaway conditions fails to meet expectations. This deficiency not only affects battery safety but also poses a potential threat to the overall performance and reliability of the battery. Therefore, this application addresses the problem of how to mitigate the influence of various factors in the presence of the aforementioned conditions, thereby better guiding the rotation of different positions of the current collector. Furthermore, this application provides, at least to address the aforementioned problems, a battery cell, a battery pack, and an electrical device.

[0031] Figure 1 A perspective view of a battery cell 100 according to some embodiments is shown. Figure 2 A schematic cross-sectional view of a battery cell 100 according to an embodiment of this application is shown. (In conjunction with...) Figure 1 and Figure 2 As shown in this embodiment, the battery cell 100 is illustrated as a cylindrical battery for example. However, this application is not limited to cylindrical battery types; it can also be other battery types such as prismatic batteries with rigid housing assemblies and explosion-proof valves. In some embodiments, the battery cell 100 can be a 4680 cylindrical battery (46mm in diameter, 80mm in height), a 4695 cylindrical battery (46mm in diameter, 95mm in height), or a 46120 cylindrical battery (46mm in diameter, 120mm in height). Here, the diameter refers to the outer diameter of the housing.

[0032] The battery cell 100 includes a housing assembly, which includes a housing 200 and a cover plate 220. The housing 200 may specifically include an end wall 111 and a side wall 109 surrounding the end wall 111. As long as a stable sealing and electrical connection can be formed, the connection between the end wall 111 and the side wall 109 can be achieved in various ways, such as integral stamping, integral casting, or separate welding. The side wall 109 can be cylindrical or follow any other closed-loop contour that matches the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, and the side wall 109 is cylindrical and surrounds the outer edge of the end wall 111. An opening 205 is formed at the end of the side wall 109 opposite to the end wall 111, and the cover plate 220 covers the opening 205. The cover plate 220 is fixedly connected to the end of the side wall 109 at the opening 205. The end of the cover plate 220 and the side wall 109 can be welded together, for example, by laser welding. The cover plate 220 and the side wall 109 can also be mechanically connected by other mechanical fixing methods. The fixed connection between the cover plate 220 and the side wall 109 needs to achieve a fixed and sealed connection relationship.

[0033] The casing 200 can be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy. The cover plate 220 can be made of steel, such as stainless steel or nickel-plated steel, or aluminum alloy or a composite material of steel and aluminum, or other materials that meet the battery energy density requirements while also possessing strength, reliability, and sealing properties. Furthermore, it can be adjusted to better suit the needs of lightweight battery designs. To prevent the casing 200 from rusting during long-term use, a rust-preventive material, such as nickel plating, can be applied to the surfaces of both the casing 200 and the cover plate 220.

[0034] The housing 200 and the cover plate 220 together define a receiving cavity for accommodating the electrode assembly 120, and a first current collector 210 and a second current collector 230 connected to the electrode assembly 120. The first current collector 210 and the second current collector 230 are connected to opposite ends of the electrode assembly 120 in its axial direction and can be electrically connected to the negative and positive electrode tabs of the electrode assembly 120, respectively. The receiving cavity can also be used to accommodate electrolyte and other necessary battery components. The direction of the cover plate 220 toward the end wall 111 is the height direction of the battery cell 100, which can be parallel to the axis Lx of the electrode assembly 120.

[0035] The electrode assembly 120 can be mainly formed by winding a positive electrode sheet and a negative electrode sheet, with a separator provided between the positive and negative electrode sheets. The wound electrode assembly 120 can have a central axial hole 120c, and the electrode assembly 120 and the central axial hole 120c can have a common axis Lx. The positive electrode sheet can include a positive current collector and a positive active material, with the positive active material coated on the surface of the positive current collector; the positive current collector can include a coated area coated with the active material and an uncoated area without the active material, and the uncoated area can be used to form the positive electrode tab of the electrode assembly 120 after winding. The negative electrode sheet includes a negative current collector and a negative active material, with the negative active material coated on the surface of the negative current collector; the negative current collector includes a coated area coated with the active material and an uncoated area without the active material, and the uncoated area can be used to form the negative electrode tab of the electrode assembly 120 after winding. Taking a lithium-ion battery cell as an example, the positive electrode current collector can be made of aluminum, and the positive electrode active material layer includes positive electrode active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode current collector can be made of copper, and the negative electrode active material layer includes negative electrode active material, which can be carbon or silicon, etc. The separator material can be, for example, PP (polypropylene) or PE (polyethylene). To protect and insulate the electrode assembly 120, an insulating film can be wrapped around the electrode assembly 120. The insulating film can be synthesized from PP, PE, PET (polyethylene terephthalate), PVC (polyvinyl chloride), or other polymer materials.

[0036] The terminal 160 can pass through the end wall 111, be fixedly connected to the end wall 111, and be insulated from the end wall 111. In some embodiments, the terminal 160 can be made of a conductive metallic material. For example, the material of the terminal 160 can be aluminum. In some embodiments, the terminal 160 is the positive terminal of the battery cell 100. Electrical insulation between the terminal 160 and the end wall 111 of the housing 200 can be achieved in various ways. For example, insulation can be achieved by placing an insulating gasket assembly between the terminal 160 and the end wall 111.

[0037] The first current collector 210 is disposed between the cover plate 220 and the electrode assembly 120. The negative electrode tab of the electrode assembly 120 may face the opening 205, and the negative electrode tab may be welded to the first current collector 210 to be electrically connected to the side wall 109 of the housing 200 or the cover plate 220 through the first current collector 210. In some embodiments, the first current collector 210 is a negative current collector. The second current collector 230 is disposed between the end wall 111 and the electrode assembly 120. The positive electrode tab of the electrode assembly 120 may face the end wall 111, and the positive electrode tab may be electrically connected to the electrode post 160 through the second current collector 230. In some embodiments, the second current collector 230 is a positive current collector. In some embodiments, the axial directions of the first current collector 210, the second current collector 230, and the electrode assembly 120 may coincide, and they may extend along the axis Lx.

[0038] In some embodiments, such as Figure 2 As shown, the sidewall 109 is provided with a groove 113 adjacent to the end of the sidewall 109 at the opening 205. The groove 113, together with the end wall 111, can restrict the movement of the electrode assembly 120 in the height direction. A first collector 210 can be located between the electrode assembly 120 and the groove 113, and the first collector 210 can be welded to the side of the groove 113 facing the electrode assembly 120. The sidewall 109 is provided with a radially inwardly extending rolled edge 132 on the periphery of the opening 205. The groove 113 and the rolled edge 132 can together hold the cover plate 220. The cover plate 220 can be insulated and sealed between the groove 113 and the rolled edge 132. In some other embodiments, the cover plate 220 can be fitted into the opening 205 in other suitable ways. For example, the side wall 109 may not have the groove 113. The cover plate 220 can be sealed by laser welding to the side wall 109. In this case, the fixing pin of the first collector plate 210 can be directly welded to the inner wall of the side wall 109 or the inner wall of the cover plate 220.

[0039] An explosion-proof valve may be provided on the cover plate 220. In some embodiments, the explosion-proof valve is an annular groove on the surface of the cover plate 220 facing the electrode assembly 120. The cover plate 220 is thinner at the groove to form a weak point in the material. In some other embodiments, other suitable structures may be used to form the explosion-proof valve.

[0040] During the use of a single battery cell, gas is generated. When the internal gas pressure reaches a certain level, the explosion-proof valve opens to at least partially open the cover 220, releasing the internal pressure and preventing the battery from exploding. When a single battery cell experiences thermal runaway, the explosion-proof valve must be able to open smoothly to release gas and prevent an explosion, ensuring the battery casing remains intact and preventing the splashing of hard materials that could cause injury to the human body.

[0041] Figure 3A plan view of a manifold according to an embodiment of this application is shown. Figure 3 The collector disk 210A shown can correspond to Figure 2 The first collector disk 210 in the system. See also... Figure 3 As shown, the current collector 210A includes a disk surface 320 and fixed pins 340 connecting the disk surface 320. The fixed pins 340 can be used for fixed connection and electrical connection with the side wall 109 of the housing assembly. The disk surface 320 has a central hole 305 in its central region. The central hole 305 can be used for electrolyte injection and electrolyte wetting. The central hole 305 can also be used as a main venting channel to increase the opening efficiency of the explosion-proof valve in the event of thermal runaway inside the battery.

[0042] The disk surface 320 may also have vent holes 360. The vent holes 360 are arranged around the central hole 305 and are spaced apart along the circumferential direction Dc of the collector disk 210A. Multiple vent holes 360 can be evenly distributed along the circumferential direction Dc. By providing vent holes 360, it is beneficial for the outer ring of the electrode assembly to release air, reducing the overall strength of the disk surface to facilitate smooth opening of the disk surface under air pressure, and facilitating the wetting of the electrode assembly by the electrolyte on the negative electrode side. A welding area 370 is formed between adjacent vent holes 360. Multiple solder marks 372 are located in the welding area 370. The solder marks 372 are formed by welding the collector disk 210A to the electrode assembly.

[0043] also, Figure 3 The dotted line in the diagram shows the fold line Lf of the panel 320, which matches the position of the explosion-proof valve on the cover plate 220. The function of the fold line Lf is to cause the panel 320 to flip to the edge of the explosion-proof valve after the valve is opened; the fold line Lf can be located at the root of the flipped portion. In actual operation, the position of the fold line Lf needs to be confirmed through experiments or simulations, taking into account the diameter of the cover plate and the assembly correspondence between the manifold and the cover plate.

[0044] According to an embodiment of this application, the disk surface 320 may further have a flip guide 390 disposed along the fold line Lf. The flip guide 390 may be connected to at least one of the vent hole 360 ​​or the center hole 305. The flip guide 390 is a thinner area compared to the surrounding disk surface 320. The flip guide 390 may be formed by methods such as thinning, material removal, or spaced openings along the trajectory. The material strength of the flip guide 390 may be less than the material strength of the welded area 370. Figure 3 In the embodiment shown, the flip guide 390 is connected to the vent 360.

[0045] To address the issue that existing current collectors do not fully flip open after thermal runaway, the technical solution of this application provides a weak flipping guide 390 along the fold line Lf of the current collector 210A. This guides the flipping by reducing the material strength, thereby reducing the folding force required for the current collector 210A to open. This ensures that the current collector 210A can flip open more smoothly after thermal runaway, effectively promoting the discharge of gas and active materials, reducing the risk of pressure buildup, and thus improving the safety and reliability of the battery.

[0046] In some embodiments, the disc portion 320 may also have multiple gaps 328. The gaps 328 may be located between the central hole 305 and the corresponding vent hole 360, and may be radially extending strip-shaped holes. After the explosion-proof valve is opened, the disc portion 320 may be radially torn at the gaps 328 to facilitate the flipping and opening of the manifold.

[0047] exist Figure 3 In the illustrated embodiment, the flipping guide 390 is an opening 395 communicating with the vent 360; that is, the flipping guide 390 is an opening structure. In this embodiment, the opening 395 communicates with the vent 360. It can be understood that by communicating the opening 395 with the vent 360, the larger opening area of ​​the vent 360 and its relatively lower material strength compared to the welding area 370 can be utilized to strengthen the opening 395 so that it tears first at the location communicating with the vent 360. However, the solution of this application is not limited to the opening 395 necessarily communicating with the vent 360; the two can also be designed to be adjacent but not communicating. In addition, the opening 395 can be a through opening along the thickness direction of the disk surface 320, or in some other embodiments, the opening 395 can be a non-through opening along the thickness direction of the disk surface 320.

[0048] In this embodiment, each opening 395 may have a rectangular outline. Along the fold line Lf, the opening 395 may be located on opposite sides of the vent 360 along the circumferential direction Dc. The area of ​​the opening 395 is smaller than the area of ​​the vent 360 it communicates with. In some embodiments, the area of ​​the opening 395 may be, for example, 0.6 mm². 2 0.8mm 2 1mm 2 2mm 2 3mm 2 4.8mm 2 or 5.6mm 2 .

[0049] The openings 395 can be distributed on opposite sides of the welding area 370 along the circumferential direction Dc, and the openings 395 on both sides of the welding area 370 are spaced apart and do not interfere with each other. By implementing the flipping guide 390 as an opening and connecting it to the vent 360, the length of the portion of the disk surface 320 along the fold line Lf is reduced to La. This reduces the folding force required when the current collector 210A is opened, and further enhances the foldability of the current collector. The openings 395 are located on both sides of the welding area 370, which avoids affecting the flatness of the welding area 370 and ensures the welding stability, integrity, and welding quality of the current collector and the electrode assembly.

[0050] Along the circumferential direction Dc of the fold line Lf, the circumferential length of each opening 395 is H, the circumferential length of the disk surface 320 is C, the total circumferential length of the disk surface 320 between adjacent openings 395 is L1 (L1 can also be called the circumferential length of the non-opening area), the total circumferential length of each opening 395 and the connected vent 360 is L2 (L2 can also be called the circumferential length of the opening area), and the total circumferential length of the multiple welding areas 370 is L3.

[0051] The circumferential length C of the disk surface 320 is C = L1 + L2, from which L1 = C - L2 can be derived. L2 is determined based on the welding area of ​​the welding zone 370, and L2 is a fixed parameter.

[0052] The circumferential length of the non-perforated area, L1, is equal to L3 plus the total circumferential length of the multiple perforations 395. The circumferential length of each perforation 395, H, is equal to the total circumferential length of the multiple perforations 395 divided by n. Therefore, the total circumferential length of the multiple perforations 395 is H × n. Thus, L1 = L3 + H × n. The appropriate value of H can be determined by comprehensively considering the values ​​of L1, L2 (related to the area of ​​the region), and L3 to ensure the ease with which the disk surface 320 flips along the fold line Lf and to ensure the welding area of ​​the welding zone 370, thereby guaranteeing DCR.

[0053] In some embodiments, the circumferential length H of a single opening 395 ranges from 1 mm to 1.5 mm. This range of circumferential length H ensures that the opening 395 can completely avoid the solder marks 372 in the welding area 370. In some embodiments, the circumferential length of a single welding area 370 ranges from 7.5 mm to 8 mm. The circumferential length of a single welding area 370 can refer to the distance along the fold line Lf on the circumferential direction Dc between the two outermost solder marks 372 in the welding area 370.

[0054] In some embodiments, solder stamp 372 can be a discontinuous solder stamp, such as... Figure 3As shown. Discontinuous solder marks 372 can be radially distributed on opposite sides of the fold line Lf. Each discontinuous solder mark 372 is a two-segment solder line distributed on both sides of the fold line Lf. In this way, the discontinuous solder marks 372 can avoid the fold line Lf; and the fact that a portion of solder marks 372 is provided on both sides of the fold line Lf can ensure the welding area, ensure that the current flow area is not affected, and avoid affecting the welding quality, avoiding soldering through the tabs, and causing electrode assembly failure. In some embodiments, the thickness of the disk surface 320 is the same on opposite sides of the fold line Lf radially. In this way, the flip guide portion 390 at the fold line Lf can not affect the thickness of the welding area 370, so as to ensure the welding quality. In some embodiments, the thickness of the un-upset area of ​​the disk surface 320 can be about 2 mm, and the thickness of the upset area can be about 0.07 mm.

[0055] The welding area 370 has a solder mark 372 formed by welding the disk surface 320 to the electrode assembly. The solder mark 372 can extend radially. In some embodiments, the solder mark 372 can be a continuous solder mark, and the continuous solder mark 372 can cross the fold line Lf radially. The continuous solder mark 372 can avoid the solder line being interrupted by interference, and can ensure that the current-carrying area is not affected, so as to ensure that the DCR (Direct Current Resistance) is not affected.

[0056] Figure 4A and Figure 4B Plan view diagrams of collector disks 210B and 210C according to other embodiments of this application are shown respectively. Figure 4A and Figure 4B Several aspects of the collector panels 210B and 210C shown above are consistent with the above references. Figure 3 The described collector panel 210A is the same as or similar to the one mentioned above. Figure 3 The beneficial effects described are mainly described below. Figure 4A and Figure 4B The differences between the collectors 210B and 210C are shown.

[0057] See Figure 4A As shown, in this embodiment, the flipping guide portion 390 of the disk surface 320 is an opening 395 communicating with the vent 360. The opening 395 has a triangular profile. The triangular opening 395 communicates with the vent 360 at one side, and a sharp angle 395c is formed between the other two sides of the triangular opening 395, extending away from the vent 360. The fold line Lf can extend through the sharp angle 395c of each opening 395.

[0058] See Figure 4BAs shown, in this embodiment, the opening 395 extends along the fold line Lf and has an elongated profile. The opening 395 may have two long sides 3951 and 3952 located on opposite sides of the fold line Lf. The two long sides 3951 and 3952 may be arc-shaped sides, and the curvature of the two arc-shaped long sides 3951 and 3952 may be substantially the same as the curvature of the fold line Lf.

[0059] It should be understood that, although Figures 3 to 4B The embodiments show that the opening 395 can have rectangular, triangular, and elongated outlines, but other shapes such as trapezoidal, racetrack-shaped, etc., can be selected according to actual needs. This diverse design choice of the opening 395 can be flexibly adjusted according to different engineering requirements and production processes to ensure process realization and optimize the flipping effect.

[0060] In some embodiments, see Figure 5A The shown collector plate 210D has a flip guide 390 on the plate surface 320, which can be a upset portion 397 provided along the fold line Lf. Figure 5A In one embodiment, the thinned portion 397 is continuous along the fold line Lf between adjacent vent holes 360. Alternatively, in other embodiments, the thinned portion 397 may be spaced apart along the fold line Lf between adjacent vent holes 360. The thinned portion 397 can be formed by upsetting the side of the manifold 210A facing the explosion-proof valve of the cover plate 220. In one example, the thinned portion 397 may be a groove formed by a stamping process. The thinned portion 397 can weaken the material at the fold line Lf, and the provision of the thinned portion 397 allows the manifold to flip with less force when subjected to internal pressure. Furthermore, the thinned portion 397 provided along the fold line Lf can be relatively uniform and continuous, ensuring the consistency of the manifold's flipping.

[0061] In some embodiments, the solder mark 372 can be a discontinuous solder mark. The discontinuous solder mark 372 can be radially distributed on both sides of the upset portion 397 at the fold line Lf. Each discontinuous solder mark 372 is a two-segment weld line distributed on both sides of the fold line Lf. In this way, the discontinuous solder mark 372 can avoid the upset portion 397 at the fold line Lf. As described above, providing a portion of solder mark 372 on both sides of the fold line Lf can ensure the welding area, ensure that the flow area is not affected, and avoid affecting the welding quality, avoiding soldering through the tab, and causing failure of the electrode assembly. In some embodiments, the thickness of the disk surface 320 on both sides of the upset portion 397 is the same in the radial direction. In this way, the upset portion 397 at the fold line Lf can not affect the thickness of the welding area 370, so as to ensure the welding quality. In some embodiments, the thickness of the un-upset area of ​​the disk surface 320 can be about 2 mm, and the thickness of the upset portion 397 can be about 0.07 mm. The radial width of the upset portion 397 can range from approximately 0.5 mm to 1 mm, which provides sufficient space for welding the manifold and electrode assembly.

[0062] In some embodiments, see Figure 5B The collector plate 210E shown has a flip guide 390 on its surface 320, which can be a plurality of openings 398 spaced along the fold line Lf. Figure 5B In the example, the opening 398 is a circular opening. In other embodiments, the opening 398 may also have other suitable shapes, such as a strip-shaped hole extending along the fold line Lf. By forming the flip guide 390 as a plurality of openings 398, the material at the fold line Lf can be weakened, allowing the manifold to flip with less force when subjected to internal pressure. In addition, the opening 398 can also facilitate the flow and wetting of the electrolyte.

[0063] As described above, by setting the flipping guide 390, the flipping force required when the collector plate is opened is reduced, and the flipping ease of the collector plate is enhanced. This beneficial effect has been verified by simulation analysis. Figure 6 A plan view of the collector disk is provided as a comparative example. For example... Figure 6 As shown, unlike the aforementioned collector trays 210A, 210B, and 210C, this collector tray 10 does not have the aforementioned flipping guide 390. The length of the portion of the tray surface 32 along the fold line Lf is Lb. Compared to Figure 3 In the embodiment shown, the length of the portion of the disk surface 320 along the fold line Lf is La. Because... Figure 6 The collector disk 10 in the middle does not have a flip guide 390, so Lb is greater than La.

[0064] To each Figure 6 The collector plate 10 shown and Figure 3Simulation was performed on the 210A collector disk shown, and the results were obtained. Figure 7 The diagram shows the relationship curves between the folding force and folding displacement of the collector disk 10 and collector disk 210A. Curve S1 represents the relationship between the folding force and folding displacement of collector disk 10, and curve S2 represents the relationship between the folding force and folding displacement of collector disk 210A. Figure 7 As shown, the maximum folding force corresponding to curve S1 is greater than the maximum folding force corresponding to curve S2, which indicates that the folding force of the collector plate 210A with the folding guide 390 is significantly reduced.

[0065] See Figure 8 This application also provides an electrical device 1000. For ease of explanation, the following embodiments use a vehicle as an example. A battery pack 1002 is installed inside the vehicle. The battery pack 1002 can be located at the bottom, head, 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 battery pack 1002 can include multiple battery cells, such as the battery cell 100 described above. Typically, multiple battery cells can be connected in series and / or in parallel to form a battery module, and then the battery modules can be connected in series and / or in parallel to form a battery pack. The battery pack can then be used as an energy system to power the vehicle or as an energy storage system. In another embodiment, the battery pack 1002 can also be a CTP (cell-to-pack) type battery pack, which omits the step of forming battery cells into battery modules, instead directly integrating multiple battery cells into a battery pack.

[0066] The working part of the electrical device 1000 is electrically connected to the battery pack 1002 to obtain electrical power. The vehicle can be a gasoline vehicle, a natural gas vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, but are not limited thereto. The working part is the vehicle body 1001, and the battery pack 1002 is located at the bottom of the vehicle body 1001, providing electrical power for the vehicle's operation or the operation of its internal electrical components. However, in some 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 obtain electrical power from the battery pack 1002 and perform corresponding functions, such as a fan blade rotation unit or a vacuum cleaner suction unit. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical equipment 1000. In some embodiments, the battery cells disclosed in this application can be applied to energy storage devices. Energy storage devices can be, but are not limited to, energy storage containers, energy storage cabinets, energy storage power stations, energy storage battery packs, or portable energy storage systems, etc. Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems, etc.

[0067] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, include: A housing assembly includes a housing and a cover plate, one end of the housing having an opening, the cover plate closing onto the opening to define a receiving cavity, and the cover plate having an explosion-proof valve; The electrode assembly is located within the receiving cavity; A collector plate is located between the electrode assembly and the cover plate; The collector plate includes a plate surface and fixed pins connecting the plate surface. The fixed pins are fixedly and electrically connected to the housing assembly. The plate surface has a central hole (305) and vent holes. The vent holes are spaced apart circumferentially along the collector plate, and a welding area is formed between adjacent vent holes. The disc surface has a fold line that matches the position of the explosion-proof valve, and the disc surface has a flipping guide portion that is arranged along the fold line. The material strength of the flipping guide portion is less than the material strength of the welding area.

2. The battery cell according to claim 1, characterized in that, The flipping guide is a through or non-through opening along the thickness direction of the disk surface; the opening is located on opposite sides of the vent hole along the circumference and communicates with the vent hole; the openings are distributed on opposite sides of the welding area along the circumference and do not interfere with each other.

3. The battery cell according to claim 2, characterized in that, The welding area has weld marks formed by welding the disk surface to the electrode assembly; In the radial direction of the manifold, the solder marks are continuous and cross the fold line; or, in the radial direction of the manifold, the solder marks are discontinuous and distributed on opposite sides of the fold line.

4. The battery cell according to claim 1, characterized in that, The flipping guide portion of the disc surface is a upset portion provided along the fold line, and the upset portions are continuous or spaced apart along the fold line.

5. The battery cell according to claim 4, characterized in that, The thickness of the disc surface is the same on both sides of the upsetting section.

6. The battery cell according to claim 2, characterized in that, Along the circumferential direction of the fold line, the circumferential length of each opening is H, the circumferential length of the disk surface is C, the total circumferential length of the disk surface between adjacent openings is L1, the total circumferential length of each opening and the connected vent is L2, and the total circumferential length of the welding area is L3. Where L1 = C - L2, L1 ≥ L3 + H × n, and n is the number of openings. The value of H ranges from 1 mm to 1.5 mm.

7. The battery cell according to claim 2, characterized in that, The opening is rectangular or racetrack-shaped; or The opening is triangular in shape, with one side of the triangle connected to the vent, and the other two sides of the triangle forming a sharp angle extending away from the vent.

8. The battery cell according to claim 1, characterized in that, The flipping guide portion of the disc surface consists of a plurality of openings spaced apart along the flipping line.

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

10. An electrical appliance, characterized in that, The battery pack includes the battery cells according to any one of claims 1 to 8.

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