Collector plate and battery cell comprising same

Abstract

The utility model provides a collector plate for a battery unit, which comprises a first electric connection part capable of being directly and electrically connected to the end part of an electrode assembly of the battery unit, and a second electric connection part capable of being directly and electrically connected to the end part of the electrode assembly, and a second electrical connection portion located radially outward of the first electrical connection portion and substantially parallel to the first electrical connection portion, the second electrical connection portion being directly electrically connectable to a terminal of the battery cell, the terminal of the battery cell being located on a second side of the collector plate opposite to the first side, in which the first electrical connection portion is formed with a through groove, and wherein the second electrical connection portion protrudes in a direction toward the second side of the collector plate with respect to the first electrical connection portion. The utility model also provides a battery unit comprising the collector plate. The collector plate and the battery unit disclosed by the utility model are simple and compact, convenient to assemble and high in reliability, and the conditions of poor contact and the like are not easy to occur.

Description

TECHNICAL FIELD

[0001] The utility model relates to a battery field especially relates to a current collection plate and including current collection plate's battery unit. BACKGROUND

[0002] With the development of society, battery in energy ratio, life and so on develops rapidly, and new energy equipment with battery especially secondary battery as energy storage device gradually is favored by consumers, and various batteries gradually are applied to various electronic equipment in large area. The battery with the electric core inside as a representative of small volume battery has the characteristics of small volume and repeated charge and discharge, and is widely applied to various consumer and industrial electronic equipment, which can significantly improve the use experience of electronic equipment.

[0003] Such secondary batteries can be classified by shape as cylindrical secondary batteries, prismatic secondary batteries, or pouch-shaped secondary batteries. Cylindrical secondary batteries have advantages of high volumetric energy density, simple structure, easy grouping, and ease of standardization. With the development of technology, cylindrical batteries gradually become the mainstream direction of the market. Cylindrical secondary batteries generally include a cylindrical electrode assembly, a cylindrical housing (also referred to as a "cylindrical can") that accommodates the electrode assembly, an electrolyte injected into the can so that ions can move, and a current collector (also referred to as a "tab") for providing electrical connection between the electrode assembly and the corresponding battery terminal to lead out the current.

[0004] The current collector is usually electrically connected between the terminal of the battery unit (for example, a positive or negative terminal formed by the housing of the battery unit or integrated in the housing) and the end portion (for example, a positive or negative end portion) of the electrode assembly within the housing of the battery unit by welding or the like. During the welding operation of the current collector of the prior art, the welding heat or other factors in the welding operation usually causes a stress change of the current collector, thereby causing the current collector to deform (especially, a larger deformation is prone to occur near the central region of the current collector), which in turn causes poor adhesion of the current collector to the electrode assembly, detachment at the welding site, poor welding performance, or even poor contact.

[0005] In addition, in order to realize the electrical connection between the terminal of the battery unit and the end portion of the electrode assembly, the prior art usually welds the current collector directly with the end portion of the electrode assembly, and additionally provides a separate connecting piece to realize the electrical connection between the current collector and the terminal of the battery unit and to support the current collector. However, this way causes an increase in the number of components in the limited space inside the battery unit, a complex structure, and easy dislocation of the components, which leads to poor contact.

[0006] Therefore, there is a need for an improved current collector and a battery cell including the current collector to solve or at least mitigate the above problems and improve the welding performance, structural compactness and reliability of the battery cell. Utility Model Content

[0007] The purpose of this invention is to provide a current collector and a battery cell including the current collector, so as to solve or at least reduce the problem of poor welding caused by deformation due to stress distribution during the welding process of the current collector in the prior art, while reducing the number of internal parts of the battery cell, so as to improve the welding performance, structural compactness and reliability of the battery cell.

[0008] To at least achieve the above objectives, according to one aspect of the present invention, a current collector for a battery cell is provided, the current collector comprising: a first electrical connection portion capable of being directly electrically connected to an end of an electrode assembly of the battery cell, wherein the end of the electrode assembly of the battery cell is located on a first side of the current collector; and a second electrical connection portion located radially outward of and substantially parallel to the first electrical connection portion, the second electrical connection portion being capable of being directly electrically connected to a terminal of the battery cell, wherein the terminal of the battery cell is located on a second side of the current collector opposite to the first side, wherein the first electrical connection portion forms a through groove and wherein the second electrical connection portion protrudes relative to the first electrical connection portion toward the second side of the current collector.

[0009] The current collector of this invention can achieve electrical connections between the current collector and the end of the electrode assembly and the terminal of the battery cell through its first and second electrical connection portions, respectively. No additional connecting components are needed; the current collector itself can achieve the electrical connection between the end of the electrode assembly and the terminal of the battery cell, thereby drawing the current from the electrode assembly. Furthermore, during the welding process, different parts of the thin-film current collector are prone to stress deformation in undesirable ways and directions due to heat, leading to poor contact. The current collector of this application effectively releases stress by providing a through groove in the first electrical connection portion, preventing poor contact or disengagement caused by deformation of the current collector during or after welding. Therefore, the current collector of this invention is simple and compact, easy to assemble, highly reliable, and less prone to poor contact.

[0010] In some preferred embodiments, the first electrical connection portion is formed with at least two through slots, each through slot extending radially outward from approximately the center of the current collector, wherein the at least two through slots are configured to divide the first electrical connection portion into multiple sub-parts.

[0011] In some preferred embodiments, the current collector is a negative current collector, wherein the first electrical connection portion can be soldered to the negative terminal of the electrode assembly located on a first side of the negative current collector to electrically connect the current collector to the negative terminal, and wherein the second electrical connection portion can be soldered to the negative terminal of the battery cell located on a second side of the negative current collector to electrically connect the current collector to the negative terminal.

[0012] In some preferred embodiments, the current collector further includes a central through-hole located radially inside the first electrical connection portion, wherein each of the through slots extends radially outward from the central through-hole.

[0013] According to this embodiment, the aforementioned central through hole and through groove allow electrolyte to pass through them to enter the electrode assembly (i.e., the battery core).

[0014] In some preferred embodiments, the at least two through slots are configured to be evenly distributed along the circumferential direction of the manifold to evenly divide the first electrical connection portion into a plurality of sub-parts.

[0015] In some preferred embodiments, each of the through slots is elongated and configured to extend radially outward from the central through hole to a position close to the connection area between the first electrical connection portion and the second electrical connection portion.

[0016] According to this embodiment, not only can the electrolyte pass-through area be increased, facilitating electrolyte passage, but it also helps release thermal stress in the first electrical connection portion and increases the elasticity of the first electrical connection portion.

[0017] In some preferred embodiments, the current collector further includes an annular circumferential edge portion extending radially outward from the second electrical connection portion, the circumferential edge portion extending in the same plane as the first electrical connection portion.

[0018] According to this embodiment, by setting the second electrical connection portion closer to the negative terminal on the second side of the current collector relative to the extension plane of the circumferential edge portion and the first electrical connection portion, the second electrical connection portion can fit more tightly with the negative terminal during assembly and welding, thereby improving welding reliability.

[0019] In some preferred embodiments, each sub-part of the first electrical connection portion can be welded to the end of the electrode assembly via a welding trajectory, which is a continuous bend, a dot, or a discontinuous line; and the second electrical connection portion can be welded to the terminal of the battery cell via a welding trajectory, which is a continuous bend, a dot, or a discontinuous line.

[0020] According to this embodiment, compared to the case where nickel metal is used as the whole material, using copper material as the whole material can make the negative electrode current collector have lower internal resistance and better conductivity, and the copper surface of the first electrical connection part can be better welded to the flattened part of the negative electrode part that is usually made of copper material; while nickel plating at the welding part can make it better welded to the shell, avoiding the problem that pure copper material is usually not easy to weld with other materials.

[0021] In some preferred embodiments, the manifold is an integral part obtained by stamping and removing material from a metal plate.

[0022] In some preferred embodiments, the thickness of each portion of the manifold is the same.

[0023] In some preferred embodiments, the ratio of the height by which the second electrical connection portion protrudes from the extension plane of the first electrical connection portion toward the second side of the current collector to the thickness of the current collector is approximately 1:15 to approximately 1:1.

[0024] In some preferred embodiments, the ratio of the width of the second electrical connection portion in the radial direction to the width of the first electrical connection portion in the radial direction is about 0.15 to about 0.35; and / or the ratio of the width of the circumferential edge portion in the radial direction to the width of the second electrical connection portion in the radial direction is about 0.1 to about 0.2.

[0025] In some preferred embodiments, the ratio of the diameter of the through slot to the width of the first electrical connection portion in the radial direction is about 0.1 to about 1.0.

[0026] In some preferred embodiments, the ratio of the diameter of the central through hole to the radial width of the first electrical connection portion is about 0.1 to about 1.0.

[0027] In some preferred embodiments, the second electrical connection portion is interconnected with the first electrical connection portion and / or the circumferential edge portion via an inclined transition portion, wherein the transition portion extends obliquely toward the second electrical connection portion on the second side.

[0028] In some preferred embodiments, the angle between the transition portion and the plane containing the first electrical connection portion is about 10° to about 90°.

[0029] In some preferred embodiments, the angle between the transition portion (424) and the plane containing the first electrical connection portion is about 30° to about 60°.

[0030] According to another aspect of the present invention, a battery cell is provided, comprising: a housing including a closed end and an open end opposite to the closed end; and an electrode assembly positioned within the housing between the closed end and the open end, the electrode assembly including a negative terminal portion near the closed end and a positive terminal portion near the open end, the battery cell further comprising a current collector according to any one of the above embodiments.

[0031] In some preferred embodiments, a negative terminal is integrated in the closed end of the housing, or the closed end forms a negative terminal, wherein the current collector is a negative current collector, the first electrical connection portion can be soldered to the negative terminal of the electrode assembly located on the first side of the negative current collector to electrically connect the current collector to the negative terminal, and wherein the second electrical connection portion can be soldered to the closed end of the housing located on the second side of the negative current collector to electrically connect the current collector to the negative terminal.

[0032] In some preferred embodiments, the second electrical connection portion can be welded to the closed end of the housing via a welding track, and the surface of the closed end of the housing facing the external space is coated with a coating that covers the welding track.

[0033] According to this embodiment, the coating can protect the weld line area between the second electrical connection part and the closed end of the housing from rust and corrosion. Attached Figure Description

[0034] To better understand the above and other objects, features, advantages, and functions of this utility model, reference can be made to the preferred embodiments shown in the accompanying drawings. The same reference numerals in the drawings refer to the same parts. Those skilled in the art should understand that the drawings are intended to schematically illustrate the preferred embodiments of this utility model and do not limit the scope of this utility model in any way; the parts in the drawings are not drawn to scale.

[0035] Figure 1 This is an exploded perspective view of a battery cell according to an embodiment of the present invention.

[0036] Figure 2 This is according to one embodiment of the present utility model. Figure 1 The diagram shows a plan view of the positive electrode, negative electrode, and separator of the battery assembly in the battery cell.

[0037] Figure 3 yes Figure 1 A schematic cross-sectional view of a portion of the battery cell shown.

[0038] Figure 4This is a perspective view of a negative current collector plate according to an embodiment of the present invention.

[0039] Figure 5 yes Figure 4 A three-dimensional view of the negative current collector from another angle.

[0040] Figure 6 yes Figure 4 The negative current collector shown is a front view viewed from the first side.

[0041] Figure 7 yes Figure 4 The negative current collector shown is viewed from the second side, opposite to the first side.

[0042] Figure 8 yes Figure 4 The cross-sectional view along the thickness direction of the negative current collector plate shown.

[0043] Explanation of reference numerals in the attached figures:

[0044] 10 Battery cell; 14 Housing; 14a Open end of housing; 14b Closed end of housing; 18 Electrode assembly; 18a Positive terminal of electrode assembly; 18b Negative terminal of electrode assembly; 62 First flattened portion; 66 Second flattened portion; 38 Positive current collector; 42 Negative current collector; 22 First insulating member; 26 Second insulating member; 70 Through hole; 30 Positive terminal; 34 Negative terminal; 46 Positive electrode sheet; 50 Negative electrode sheet; 54 Separator; 5 8. Center hole; 42a. First side of negative current collector; 42b. Second side of negative current collector; 421. First electrical connection portion of negative current collector; 4211. Through slot of first electrical connection portion; 4212. Center through hole of first electrical connection portion; 4213. First welding line; 422. Second electrical connection portion of negative current collector; 4221. Joint surface of second electrical connection portion; 4223. Second welding line; 423. Circumferential edge portion of negative current collector; 424. Transition portion. Detailed Implementation

[0045] Now, with reference to the accompanying drawings, specific embodiments of the present invention will be described in detail. The embodiments described herein are merely preferred embodiments of the present invention; those skilled in the art can conceive of other ways to implement the present invention based on these preferred embodiments, and such other ways also fall within the scope of the present invention.

[0046] First, it should be noted that the relative positions of the components within the battery cell described below are all based on the condition that the components are correctly assembled.

[0047] This utility model discloses a current collector for a battery cell, and a battery cell including the current collector. Next, we will first combine... Figure 1This describes a battery cell according to an embodiment of the present invention. The battery cell 10 includes a generally cylindrical housing 14 configured as a cylindrical can with one open end, comprising an open end 14a and a closed end 14b opposite the open end. The battery cell 10 further includes a cover capable of engaging with the open end 14a of the housing 14 to close the interior of the housing; and an electrode assembly 18, a first insulating member 22, and a second limiting member 26 located inside the housing.

[0048] The battery cell 10 also includes a positive terminal 30 located at the open end 14a of the housing 14, a negative terminal 34 located at the closed end 14b of the housing 14, and a first conductor (in this embodiment, a positive current collector 38) located in the housing 14 between the electrode assembly 18 and the positive terminal 30. Figure 1 The positive current collector is shown schematically as a roughly circular sheet component and does not represent its specific shape, and the second conductor (in this embodiment, the negative current collector 42) located between the electrode assembly 18 and the negative terminal 34 in the housing 14 is also shown. Figure 1 The negative current collector is only schematically shown as a roughly circular sheet component and does not represent its actual shape. The specific shape and structure are described in [the diagram / illustration]. Figures 4-7 (Exemplary illustration shown below and described in detail below). The positive terminal 30 and negative terminal 34 of the battery cell are used to draw out the current inside the battery cell, thereby providing electrical contact with external devices, such as electrical connection to charging devices, electrical appliances, or for realizing electrical connection between different battery cells.

[0049] The positive terminal 30 can be integrated into the cover portion. In this case, the cover portion can be made of a non-conductive material such as plastic, and the electronic component serving as the positive terminal 30 can be integrated into the cover portion. Alternatively, the positive terminal 30 can be formed directly from the cover portion. In this case, the cover portion can be made of a conductive metal material such as steel, aluminum, or other materials, thus serving directly as the positive terminal. Similarly, the negative terminal 34 can be integrated into the closed end 14b of the housing 14. In this case, the housing can be made of a non-conductive material such as plastic, and the electronic component serving as the negative terminal 34 can be integrated into the closed end 14b of the housing 14. Alternatively, the negative terminal 34 can be formed directly from the housing 14. In this case, the housing can be made of a conductive metal material such as steel, aluminum, or other materials, thus serving directly as the negative terminal.

[0050] refer to Figure 2 The electrode assembly 18 includes a positive electrode 46, a negative electrode 50, and one or more separators 54 (i.e., insulating sheets 54) located between the positive electrode 46 and the negative electrode 50. Figure 3As shown, multiple sheets can be wound concentrically around the central hole 58 of the electrode assembly 18 to form a core. In some embodiments, the electrode assembly 18 is wound around a central pin, which can be removed after the winding operation is completed. After winding, the exposed or uncoated portions of the positive electrode 46 form the positive terminal 18a of the electrode assembly 18, and the exposed or uncoated portions of the negative electrode 50 form the negative terminal 18b of the electrode assembly 18. The exposed portions at the positive terminal 18a can be flattened into a flat, rough surface to form a first flattened portion 62, and the exposed portions at the negative terminal 18b can be flattened into a flat, rough surface to form a second flattened portion 66. The first flattened portion 62 provides a bonding surface for the first conductor, allowing the first conductor to be bonded (e.g., welded, fixed, adhered, fastened, etc.) to the electrode assembly 18. Similarly, the second flattened portion 66 provides a bonding surface for the second conductor.

[0051] The first insulating member 22 described above is made of plastic and / or rubber. The first insulating member 22 may be provided with a through-hole 70, which allows the first conductor to extend through the first insulating member 22 and contact the first terminal 30. A first flattened portion 62 may be arranged or disposed in the first insulating member 22 to prevent contact between the first flattened portion 62 and the housing 14. The first terminal 30 may be arranged in a second insulating member 26 supported on the first insulating member 22. Once the electrode assembly 18 and other electronic components are arranged in the housing 14, the first insulating member 22 and the second insulating member 26 are pressed onto the first terminal 30.

[0052] In this embodiment, the first conductor and the second conductor described above are formable (e.g., flexible, compliant, maneuverable, etc.) current collectors, current collectors, busbars, or other components capable of electrically connecting the positive terminal 18a and the negative terminal 18b of the electrode assembly to the positive terminal 30 and the negative terminal 34 of the battery cell, respectively.

[0053] To address the problems of poor welding and low reliability caused by deformation during welding of existing current collectors, and to solve the issues of numerous, complex, and insufficiently compact components in existing current collectors, this invention provides a current collector for a battery cell. The current collector includes: a first electrical connection portion electrically connected to the end of an electrode assembly of the battery cell, wherein the end of the electrode assembly is located on a first side of the current collector; and a second electrical connection portion located radially outward and substantially parallel to the first electrical connection portion, electrically connected to a terminal of the battery cell, wherein the terminal of the battery cell is located on a second side of the current collector opposite to the first side. The first electrical connection portion forms a through groove, and the second electrical connection portion protrudes relative to the first electrical connection portion toward the second side of the current collector.

[0054] The current collector of this invention can achieve electrical connections between the current collector and the end of the electrode assembly and the terminal of the battery cell through its first and second electrical connection portions, respectively. No additional connecting components are needed; the current collector itself can achieve the electrical connection between the end of the electrode assembly and the terminal of the battery cell, thereby drawing the current from the electrode assembly. Furthermore, during the welding process, different parts of the thin-film current collector are prone to stress deformation in undesirable ways and directions due to heat, leading to poor contact. The current collector of this application effectively releases stress by providing a through groove in the first electrical connection portion, preventing poor contact or disengagement caused by deformation of the current collector during or after welding. Therefore, the current collector of this invention is simple and compact, easy to assemble, highly reliable, and less prone to poor contact.

[0055] The current collector according to this utility model can be used as a positive current collector for the first conductor or as a negative current collector for the second conductor. Next, refer to... Figures 4 to 8 The embodiments described herein, using the negative electrode current collector 42 as an example, illustrate the current collector according to the present invention. All or part of the structures, technical features, connection relationships, etc., described herein are also applicable to the positive electrode current collector. Those skilled in the art can choose to use the current collector of the present invention for the positive or negative electrode of the battery cell according to actual needs.

[0056] Figure 4 and Figure 5Perspective views of the negative current collector according to the present invention, viewed from the second side 42b and the first side 42a, are shown respectively. The end of the electrode assembly 18 of the battery cell 10 (the negative terminal 18b in this embodiment) is located on the first side 42a of the negative current collector 42, and the terminal of the battery cell 10 (the negative terminal 34 in this embodiment) is located on the second side 42b of the negative current collector 42 opposite to the first side 42a. It should be noted that the first side and the second side mentioned above refer to the state in which the negative current collector is correctly assembled into the battery cell.

[0057] The negative current collector 42 includes a first electrical connection portion 421 that can be directly electrically connected to the negative terminal portion 18b of the electrode assembly 18. That is, the first electrical connection portion 421 is in direct contact and electrically connected to the negative terminal portion 18b, and no other components are provided between them for achieving the electrical connection. For example, the first electrical connection portion 421 can be soldered to the second flattened portion 66 of the negative terminal portion 18b to achieve the electrical connection between the current collector and the electrode assembly. The negative current collector 42 also includes an annular second electrical connection portion 422 extending radially outward from the first electrical connection portion 421. The second electrical connection portion 422 can be electrically connected to the negative terminal 34 of the battery cell 10. That is, the second electrical connection portion 422 is in direct contact and electrically connected to the negative terminal 34, and no other components are provided between them for achieving the electrical connection. For example, the second electrical connection portion 422 can be welded to the inner wall of the closed end 14b of the housing 14 of the battery cell 10, which integrates the negative terminal 34 or forms the negative terminal 34 itself, to achieve an electrical connection between the current collector and the housing of the battery cell.

[0058] The first electrical connection portion 421 has a through groove to release thermal stress and prevent overall deformation of the first electrical connection portion due to thermal stress during or after welding, which could lead to poor contact. The through groove also increases the overall elasticity of the current collector, ensuring good electrical connection function even if the battery cell is dropped or impacted during transportation or use. Furthermore, the through groove extends through the thickness of the current collector, allowing electrolyte to pass through.

[0059] Those skilled in the art can select the shape, location, extension direction, size, and number of the through-slots as needed. For example, the through-slot can extend from one circumferential edge of the first electrical connection to another circumferential edge, or it can extend from one circumferential edge to a radially inward position within the first electrical connection, or it can extend only within the internal region of the first electrical connection without reaching the circumferential edge. The through-slot can have a bent shape, a long strip shape extending in a generally straight direction, a teardrop shape, or a triangular shape, etc. The number of through-slots can be one or more. This utility model is not intended to limit the location, direction, number, shape, size, etc. of the through-slots, as long as the through-slots can achieve the purpose of releasing thermal stress during welding and increasing the overall elasticity of the manifold.

[0060] In a preferred embodiment, the first electrical connection portion 421 has at least two through slots 4211, each extending radially outward from approximately the center of the manifold, wherein the at least two through slots 4211 are configured to divide the first electrical connection portion into multiple sub-portions. Preferably, the at least two through slots 4211 are configured to be evenly distributed along the circumferential direction of the manifold to evenly divide the first electrical connection portion into multiple sub-portions. Figure 4 As shown, in this embodiment, three through slots are preferably provided along the circumferential direction of the manifold, and the interval angle between each pair of these three through slots is the same, that is, 120 degrees. In this way, the first electrical connection portion in this embodiment is divided into three approximately fan-shaped sub-parts with a central angle of 120 degrees by the three through slots. Preferably, the ratio of the diameter of each through slot to the width of the first electrical connection portion in the radial direction is about 0.1 to 1.0.

[0061] Furthermore, the second electrical connection portion 422 protrudes towards the second side 42b of the current collector relative to the first electrical connection portion 421. That is, the extending plane of the second electrical connection portion 422 is closer to the closed end 14b of the battery cell casing than the extending plane of the first electrical connection portion 421. This arrangement of the first and second electrical connection portions on different planes allows both connection portions to be closer to their respective connected components (negative terminal 14b and negative terminal 34), facilitating welding and assembly. This structure also increases the current collector's tolerance to stress deformation: since the first and second electrical connection components extend on different planes, stress deformation in one will not affect or will have a minimal impact on the other, thus preventing the two portions from pulling against each other and causing poor contact or disengagement between the two portions and their respective welded components.

[0062] The battery cells using the current collector according to this invention exhibit high reliability and good electrical connection characteristics. For example, when multiple battery cells using the current collector were subjected to a tumble drop test in an uncharged state with 0% remaining charge, the electrical connection characteristics of the battery cells remained undamaged, demonstrating a 100% pass rate in the test. This indicates high welding reliability between the current collector and the negative terminal of the battery assembly, as well as between the current collector and the battery cell housing.

[0063] Furthermore, the negative electrode current collector also includes a central through-hole 4212 located radially inside the first electrical connection portion 421, wherein each of the slots 4211 extends radially outward from the central through-hole 4212. Both the central through-hole 4212 and the aforementioned slots 4211 allow electrolyte to pass through them to enter the electrode assembly (i.e., the battery core). Each of the slots 4211 can be elongated (e.g.,...). Figure 4 As shown, the through-slot can also be teardrop-shaped or triangular, and is configured to extend radially outward from the central through-hole 4212 to a position close to the connection area between the first electrical connection portion 421 and the second electrical connection portion 422 (i.e., the extension length of the through-slot spans most of the radial dimension of the first electrical connection portion). This configuration not only increases the area through which the electrolyte can pass, facilitating electrolyte passage, but also helps release thermal stress in the first electrical connection portion, increasing the elasticity of the first electrical connection portion.

[0064] More preferably, such as Figure 8 As shown, the negative electrode current collector 42 may further include an annular circumferential edge portion 423 extending radially outward from the second electrical connection portion 422, the circumferential edge portion 423 extending in the same plane as the first electrical connection portion 421. When the first electrical connection portion 421 is connected to the negative terminal of the electrode assembly, the circumferential edge portion 423 and the first electrical connection portion 421 simultaneously abut against the negative terminal of the electrode assembly, which is beneficial for the positioning of the first electrical connection portion 421. At the same time, since the second electrical connection portion 422 is supported on both sides, it can also prevent the second electrical connection portion 422 from deforming in the axial direction. When the second electrical connection portion 422 is electrically connected to the closed end of the housing of the battery cell 10, the second electrical connection portion 422 abuts against the closed end to form a planar contact, and the second electrical connection portion 422 fits more tightly with the inner side of the closed end 14b of the housing 14, thereby improving the welding reliability. Preferably, the area ratio of the second electrical connection portion (422) to the current collector (42) is about 0.3 to about 0.6. The welding area of ​​the second electrical connection portion 422 is large, which effectively improves the welding yield. In the process of assembling the battery cell into a battery pack, the welding portion needs to be welded to the conductor. The large welding area can ensure the yield of secondary welding.

[0065] Preferably, the first electrical connection portion 421 of the negative current collector of this application can be electrically connected to the negative terminal of the electrode assembly by welding, and the second electrical connection portion 422 can be electrically connected to the closed end 14b of the housing by welding. The welding can be laser welding. The welding trajectory can be a continuous weld line (e.g., a continuously bent weld line), a discontinuous weld line, or a dotted weld line, etc. In one embodiment, the welding trajectory can be a continuous weld line, which greatly increases the welding contact area and can significantly improve the charging and discharging rate of the battery cell.

[0066] In a preferred embodiment of this invention, the welding trajectories of the first and second electrical connection portions are both continuous welding lines, and laser welding is performed along these welding lines. Each sub-part of the first electrical connection portion 421 can be laser welded to the negative end portion of the electrode assembly (e.g., via a continuous first welding line 4213 extending from the radially inward side to the radially outward side of that sub-part through multiple bends). Figure 6 An exemplary first weld line 4213 of one sub-part of the first electrical connection portion 421 is shown. It is understood that other sub-parts can be welded to the negative terminal using the same or similar weld lines. This multi-bending extension of the first weld line significantly increases the weld line length, thereby increasing the electrical contact area between the first electrical connection portion and the negative terminal, and improving the current transmission rate. The second electrical connection portion 422 can be laser-welded to the terminals of the battery cell (e.g., via a loop-shaped second weld line 4223 extending parallel to the second electrical connection portion) Figure 7 (The opening shown is a ring-shaped weld line).

[0067] Furthermore, the ratio of the radial width of the second electrical connection portion to the radial width of the first electrical connection portion is approximately 0.15 to approximately 0.35. The ratio of the radial width of the circumferential edge portion to the radial width of the second electrical connection portion is approximately 0.1 to approximately 0.2. Thus, both the first and second electrical connection portions have a large area for welding. In particular, the first electrical connection portion has a larger proportion in the current collector, which is beneficial for its direct welding operation with the battery core.

[0068] Preferably, the ratio of the diameter of the central through hole 4212 to the width of the first electrical connection portion in the radial direction is about 0.1 to about 1.0.

[0069] Preferably, the closed end 14b of the housing 14 is coated with a coating that covers the welding trace of the second electrical connection portion (in this embodiment, it covers the second welding line 4223, and the coating is preferably an annular coating corresponding to the position and shape of the second welding line). The coating is used to protect the second welding line 4223 on the side of the closed end facing the external space and prevent the housing from rusting and being corroded by the second welding line and the annular area around it.

[0070] In the welding step of the battery manufacturing process, the negative current collector is welded to the negative end of the electrode assembly (in this step, the first side of the negative current collector is first made to be in close contact with the negative end of the electrode assembly, and then a laser is applied from the second side of the negative current collector to form the aforementioned continuous first welding line); then the electrode assembly together with the negative current collector is placed into the housing of the battery cell, and a laser is applied from the closed end of the housing facing the outside of the external space to form the aforementioned continuous second welding line.

[0071] Since the welding area between the current collector and the negative terminal is located inside the housing, the laser welding process for forming the first weld line does not damage the housing. Therefore, there is no need to apply an additional protective layer or material to the first electrical connection area. However, forming the second weld line involves applying a laser directly to the closed end of the housing. Therefore, a protective coating needs to be applied to the weld path corresponding to the second electrical connection portion at the closed end of the housing during the UV spraying process to prevent rusting and thus protect the second weld line from failure.

[0072] Therefore, using the current collector according to this invention means that only the surface of the closed end 14b of the housing 14 facing the external space needs to be coated with an annular coating corresponding to the position and shape of the second electrical connection portion, and it is not necessary to coat other areas of this surface of the closed end with a protective coating. This saves materials and simplifies the manufacturing process.

[0073] More preferably, the negative current collector 42 is made of a conductive material, such as copper, nickel, or an alloy. In one embodiment, the negative current collector 42 comprises copper, and the mating surface 4221 of the second electrical connection portion 422 facing the battery cell terminal and engaging with the terminal is plated with nickel. That is, the base of the negative current collector is made of copper, and nickel is plated only on the mating surface 4221 where welding to the housing is required. Compared to using nickel as the entire material, the use of copper as the entire material in this embodiment allows the negative current collector to have lower internal resistance and better conductivity, and the copper surface of the first electrical connection portion can be better welded to the flattened portion of the negative terminal, which is usually made of copper; while nickel plating at the welding point allows for better welding to the housing, avoiding the problem that pure copper is generally not easy to weld with other materials.

[0074] Preferably, the aforementioned manifold is an integral part obtained by stamping and removing material from a metal plate, and its thickness is uniform, meaning that the thickness of each part of the manifold is substantially the same. More preferably, the ratio of the height h of the second electrical connection portion protruding from the extension plane of the first electrical connection portion toward the second side of the manifold to the thickness t of the manifold is approximately 1:15 to approximately 1:1.

[0075] Preferably, the second electrical connection portion 422 is interconnected with the first electrical connection portion 421 and / or the circumferential edge portion 423 via an inclined transition portion 424, wherein the transition portion extends obliquely toward the second electrical connection portion 422 from the second side 42b. This arrangement allows for a smoother transition between the portions of the negative current collector, making it less prone to breakage when the current collector undergoes stress deformation due to heat. Preferably, the angle formed between the transition portion 424 and the plane containing the first electrical connection portion 421 is approximately 10° to approximately 90°; more preferably, the angle formed between the transition portion 424 and the plane containing the first electrical connection portion is approximately 30° to approximately 60°; even more preferably, the angle formed between the transition portion 424 and the plane containing the first electrical connection portion 421 is 30°, 45°, or 60°.

[0076] The present invention also provides a battery cell 10, comprising: a housing 14, the housing including a closed end 14b and an open end 14a opposite to the closed end; and an electrode assembly 18, the electrode assembly being positioned inside the housing 14, located between the closed end 14b and the open end 14a, the electrode assembly 18 including a negative terminal portion 18b near the closed end 14b and a positive terminal portion 18a near the open end 14a, wherein the battery cell also includes the current collector discussed above.

[0077] It should be noted that the embodiments of this utility model can be combined and / or modified in various ways, and the results of such combinations and / or modifications should also be considered as embodiments of this utility model. The above description of various embodiments of this utility model is provided for descriptive purposes to a person skilled in the art. It is not intended to exclude or limit this utility model to a single disclosed embodiment. Those skilled in the art will understand various alternatives and variations of this utility model based on the above teachings. Therefore, although some alternative embodiments have been specifically described, those skilled in the art will understand or relatively easily develop other embodiments. This utility model is intended to include all alternatives, modifications, and variations of the utility model described herein, as well as other embodiments falling within the spirit and scope of the utility model described above.

Claims

1. A current collector (42) for a battery cell (10), characterized in that The current collecting plate comprises: a first electrical connection portion (421) capable of being directly electrically connected to an end of an electrode assembly of the battery cell, wherein the end of the electrode assembly of the battery cell is located at a first side (42a) of the current collecting plate; and a second electrical connection portion (422) located radially outward of the first electrical connection portion and substantially parallel to the first electrical connection portion, the second electrical connection portion being capable of being directly electrically connected to a terminal of the battery cell, wherein the terminal of the battery cell is located at a second side (42b) of the current collecting plate opposite to the first side (42a), wherein the first electrical connection portion (421) is formed with a through slot (4211), and wherein the second electrical connection portion (422) protrudes towards the second side (42b) of the current collecting plate relative to the first electrical connection portion (421).

2. The current collector plate (42) according to claim 1, characterized in that The first electrical connection portion (421) is formed with at least two through slots (4211), each of which extends outward in a radial direction from a substantially central position of the current collecting plate, wherein the at least two through slots (4211) are configured to divide the first electrical connection portion into a plurality of sub-portions.

3. The current collector plate (42) according to claim 1 or 2, characterized in that The current collecting plate is a negative current collecting plate, wherein the first electrical connection portion (421) is capable of being welded to a negative end (18b) of the electrode assembly (18) located at the first side (42a) of the negative current collecting plate to electrically connect the current collecting plate to the negative end, and wherein the second electrical connection portion (422) is capable of being welded to a negative terminal of the battery cell located at the second side (42b) of the negative current collecting plate to electrically connect the current collecting plate to the negative terminal.

4. The current collector plate (42) according to claim 2, characterized in that The current collecting plate further comprises a central through hole (4212) located radially inward of the first electrical connection portion (421), wherein each of the through slots (4211) extends outward in a radial direction from the central through hole (4212).

5. The current collector plate (42) according to claim 2, characterized in that The at least two through slots (4211) are configured to be evenly distributed along a circumferential direction of the current collecting plate to evenly divide the first electrical connection portion into a plurality of sub-portions.

6. The current collector plate (42) according to claim 4, characterized in that Each of the through slots (4211) is in a long strip shape and is configured to extend outward in a radial direction from the central through hole to a position close to a connection region of the first electrical connection portion (421) and the second electrical connection portion (422).

7. The current collector plate (42) according to claim 1 or 2, characterized by The current collecting plate further comprises: a ring-shaped circumferential edge portion (423) extending outward in a radial direction from the second electrical connection portion (422), the circumferential edge portion (423) extending in the same plane as the first electrical connection portion (421).

8. The current collecting plate (42) according to claim 5, characterized in that, each sub-portion of the first electrical connection portion (421) is capable of being welded to the end of the electrode assembly via a welding trace, the welding trace being a continuously bent extension line, a dot or a discontinuous line; and The second electrical connection portion (422) is solderable to the terminal of the battery cell via a soldering track, which is a continuous extension, a dot or a discontinuous line.

9. The current collector plate (42) according to claim 1 or 2, characterized by The current collecting plate is a monolithic piece obtained by a stamping operation and a material removal operation on a metal sheet.

10. The current collector plate (42) according to claim 1 or 2, characterized by The thickness of each portion of the current collecting plate is the same.

11. The current collector plate (42) according to claim 1, characterized in that The ratio of the height (h) by which the second electrical connection portion (422) protrudes from the extension plane of the first electrical connection portion (421) towards the second side of the current collecting plate to the thickness (t) of the current collecting plate is about 1:15 to about 1:

1.

12. The current collecting plate (42) according to claim 7, characterized in that The ratio of the width of the second electrical connection portion in the radial direction to the width of the first electrical connection portion in the radial direction is about 0.15 to about 0.35; and / or The ratio of the width of the circumferential edge portion in the radial direction to the width of the second electrical connection portion in the radial direction is about 0.1 to about 0.

2.

13. The current collecting plate (42) according to claim 1 or 2, characterized in that The ratio of the diameter of the through slot (4211) to the width of the first electrical connection portion in the radial direction is about 0.1 to about 1.

0.

14. The current collecting plate (42) according to claim 4, characterized in that The ratio of the diameter of the central through hole (4212) to the width of the first electrical connection portion in the radial direction is about 0.1 to about 1.

0.

15. The current collecting plate (42) according to claim 7, characterized in that The second electrical connection portion (422) is connected to the first electrical connection portion (421) and / or the circumferential edge portion (423) by a beveled transition portion (424), wherein the transition portion extends obliquely towards the second electrical connection portion (422) at the second side (42b).

16. The current collecting plate (42) according to claim 15, characterized in that The angle formed by the transition portion (424) and the plane of the first electrical connection portion is about 10° to about 90°.

17. The current collecting plate (42) according to claim 16, characterized in that The angle formed by the transition portion (424) and the plane of the first electrical connection portion is about 30° to about 60°.

18. A battery cell (10) comprising: a housing (14) comprising a closed end portion (14b) and an open end portion (14a) opposite the closed end portion; and an electrode assembly (18) positioned within the housing (14) between the closed end portion (14b) and the open end portion (14a), the electrode assembly (18) comprising a negative end portion (18b) proximate the closed end portion (14b) and a positive end portion (18a) proximate the open end portion (14a), characterized in that the battery cell further comprises a current collecting plate (42) according to any one of claims 1 to 17.

19. The battery cell (10) according to claim 18, characterized in that ​ a negative terminal (34) is integrated in the closed end (14b) of the housing (14), or the closed end forms the negative terminal (34), wherein the current collector plate is a negative current collector plate, the first electrical connection portion (421) is capable of being welded to a negative end portion (18b) of the electrode assembly located at a first side (42a) of the negative current collector plate to electrically connect the current collector plate to the negative end portion, and wherein the second electrical connection portion (422) is capable of being welded to a closed end (14b) of the housing located at a second side (42b) of the negative current collector plate to electrically connect the current collector plate to the negative terminal (34).

20. The battery cell (10) according to claim 19, characterized in that the second electrical connection portion (422) is capable of being welded to the closed end of the housing via a welding track, and a surface of the closed end (14b) of the housing (14) facing an outer space is coated with a coating covering the welding track.

21. The battery cell (10) according to claim 20, characterized in that the coating is a layer of a conductive material.

22. The battery cell (10) according to claim 21, characterized in that the layer of the conductive material is a layer of a conductive adhesive.

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