Description:BACKGROUND
[0001]
Current collector plates play a crucial role in secondary battery cells, facilitating the efficient transfer of electrical current between the electrode assembly and external terminals. These plates are typically 5 manufactured from conductive metals and are designed to provide reliable electrical connectivity while maintaining mechanical integrity throughout the operational life of the battery cell. Current collector plates may be configured with various structural features to optimize their interface with electrode assemblies and terminal connections. 10
[0002]
Current collector plates are typically connected to rivets or terminals to complete the electrical circuit within the battery cell. The design and manufacturing of current collector systems involve considerations of material selection, structural configuration, and assembly methods to ensure optimal performance in various battery applications. Current 15 collector plates may incorporate different design features and connection mechanisms depending on the specific requirements of the battery cell architecture.
BRIEF DESCRIPTION OF FIGURES 20
[0003]
Systems and/or methods, in accordance with examples of the present subject matter are described and with reference to the accompanying figures, in which:
[0004]
FIG. 1A illustrates a perspective view of a current collector plate, in accordance with an example of the present subject matter; 25
[0005]
FIG. 1B illustrates a cross-sectional view of the current collector plate, according to an example of the present subject matter;
[0006]
FIG. 2 is an exploded view of a secondary cell, in accordance with an example of the present subject matter;
3
[0007]
FIG. 3 is a cross-sectional view of a secondary cell, in accordance with an example of the present subject matter;
[0008]
FIG. 4A illustrates a perspective view of a current collector plate, in accordance with another example of the present subject matter;
[0009]
FIG. 4B illustrates a cross-sectional view of the current collector 5 plate, according to another example of the present subject matter;
[0010]
FIG. 5 is an exploded view of a secondary cell, in accordance with another example of the present subject matter; and
[0011]
FIG. 6 is a cross-sectional view of a secondary cell, in accordance with another example of the present subject matter. 10
[0012]
It may be noted that throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings provide examples and/or implementations consistent with the 15 description; however, the description is not limited to the examples and/or implementations provided in the drawings.
DETAILED DESCRIPTION
[0013]
Current collector plates in secondary battery cells face significant 20 challenges in establishing reliable electrical connections between electrode assemblies and external terminals. Traditional current collector designs often rely on single-material construction, which may limit the ability to optimize both the electrode interface characteristics and the terminal connection properties simultaneously. The electrode assembly interface 25 typically requires specific material properties for optimal current collection, while the terminal connection may benefit from different material characteristics to ensure reliable electrical connectivity and mechanical durability.
4
[0014]
Conventional current collector plates may also encounter difficulties in achieving secure mechanical and electrical connections to battery terminals while maintaining structural integrity. The connection between the current collector plate and the terminal components often requires robust bonding methods that can withstand the mechanical 5 stresses and thermal cycling experienced during battery operation. Additionally, the geometric constraints within battery cells may limit the design flexibility of current collector plates, making it challenging to optimize both the current collection efficiency and the terminal connection reliability.
[0015]
The present subject matter pertains to a secondary cell and a 10 current collector plate for the secondary cell, designed to incorporate a connection member made of a different metal than the current collector plate itself. This multi-metal configuration allows for optimization of material properties at different functional areas of the current collector assembly, enabling enhanced performance characteristics for both electrode 15 interfacing and terminal connections.
[0016]
The current collector plate may include a frame portion to facilitate coupling with an electrode assembly of the secondary cell. The frame portion provides mechanical support and electrical connectivity to the electrode components. The current collector plate may further include a 20 terminal portion that is coupled to and spaced apart from the frame portion. The terminal portion comprises a top face and a bottom face. In an example, the top face may serve as a platform for connection components and the bottom face potentially interfacing with other cell components.
[0017]
Additionally, the current collector plate may include a connection 25 member disposed on the top face of the terminal portion. The connection member is specifically designed for being coupled to a terminal of the secondary cell. In an example, the connection member is made of a different metal than that of the current collector plate.
5
[0018]
Accordingly, the present subject matter provides several advantages. The use of dissimilar metals in the current collector plate and connection member allows for the selection of materials with complementary properties that optimize both current collection efficiency and terminal connection reliability. This multi-metal approach may enable 5 improved electrical conductivity, enhanced corrosion resistance, and better thermal management characteristics compared to single-material designs. The mechanical coupling between the connection member and the terminal portion may provide secure electrical connectivity while maintaining structural integrity throughout the operational life of the battery cell. 10
[0019]
The above-mentioned implementations are further described herein with reference to the accompanying figures. It should be noted that the description and figures relate to exemplary implementations and should not be construed as a limitation to the present subject matter. It is also to be understood that various arrangements may be devised that, although not 15 explicitly described or shown herein, embody the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and embodiments of the present subject matter, as well as specific examples, are intended to encompass equivalents thereof.
[0020]
FIG. 1A illustrates a perspective view of a current collector plate 20 100 in accordance with an example of the present subject matter. The current collector plate 100 is configured for being connected to an electrode assembly (not shown) of a secondary battery and facilitate efficient electrical connectivity and mechanical coupling. In an example, the current collector plate 100 may function as either an anode current collector or a cathode 25 current collector depending on the specific battery configuration and application requirements.
[0021]
The current collector plate 100 includes a frame portion 102 for coupling with the electrode assembly. The frame portion 102 may have a configuration that corresponds to and complements the geometry of the 30
6
electrode assembly, allowing the current collector plate 100 to interface with and secure the electrode assembly within the secondary cell. The frame portion 102 may adopt various shapes including annular, ring-like, polygonal, or other geometric configurations depending on the specific design and arrangement of the electrode assembly. The configuration of the 5 frame portion 102 may be adapted to match the outer periphery or structural characteristics of the electrode assembly, ensuring optimal coupling and alignment between these components.
[0022]
In an example, the frame portion 102 may define an outer periphery 104 and an inner periphery 106, with the inner periphery 106 10 providing the coupling interface for the electrode assembly. The frame portion 102 may be a flat, conductive plate that forms a primary electrical connection between the electrode assembly and an external circuit of the secondary cell. In an example, the frame portion 102 may be made from a conductive material, such as copper, aluminum, or a coated metal to offer 15 low electrical resistance and good thermal conductivity.
[0023]
Further, the current collector plate 100 includes a terminal portion 108 coupled to and spaced apart from the frame portion 102. The terminal portion 108 may include a top face 110. As the name indicates, the terminal portion 108 serves as the primary interface for terminal connections and 20 provides a dedicated platform for establishing electrical connectivity with external terminal components of the secondary cell. In an example, the terminal portion 108 may be positioned centrally relative to the frame portion 102. The terminal portion 108 may have a circular, square, rectangular, or other geometric shape when viewed from above, and may be dimensioned 25 to provide adequate surface area for connection components. The spacing between the terminal portion 108 and the frame portion 102 may create a structural separation that allows for independent positioning and orientation of these components, with the spacing distance being adjustable based on design requirements. 30
7
[0024]
In an example, the current collector plate 100 may include at least two flanges 112 that extend from the inner periphery 106 of the frame portion 102 towards the terminal portion 108. As is evident from FIG. 1, the at least two flanges 112 are integral to the frame portion 102 and have a variable width. In another example, the at least two flanges 112 may have 5 constant width. In other words, the at least two flanges 112 may have various lengths, widths, and thicknesses, and may extend radially inward from the frame portion 102 at different angles and orientations. As is evident from FIG. 1, in the current collector plate 100, a plane of the frame portion 102 is same as the plane of the at least two flanges 112. The co-planarity 10 of the frame portion 102 with the at least two flanges 112 may ensure a uniform and consistent thickness across the current collector plate 100. This also facilitates maintaining structural integrity and uniform current distribution.
[0025]
In addition, the at least two flanges 112 divide an inner area of 15 the frame portion 102 to create two or more slots 114 in the frame portion 102. The two or more slots 114 are openings or gaps formed between adjacent flanges 112 and may have various widths, lengths, and shapes, including rectangular, curved, or tapered configurations. The two or more slots 114 provide pathways for connecting elements between the frame 20 portion 102 and the terminal portion 108. In an example, the two or more slots 114 may be designed to provide space to accommodate the physical expansion of the electrode assembly during charging and discharging cycles of the secondary cell. As a result, the two or more slots 114 mitigate mechanical stress and potential damage to the electrode assembly. 25
[0026]
Further, the current collector plate 100 includes at least two arms 116, positioned in the two or more slots 114, such that the at least two arms 116 are arranged radially on the frame portion 102. The at least two arms 116 may converge from the inner periphery 106 of the frame portion 102 towards a center of the frame portion 102 to connect the terminal portion 30
8
108 with the frame portion 102. As is evident from FIG. 1, the at least two arms 116 may be spaced apart from the at least two flanges 112, i.e., the arms 116 may not make contact with the flanges 112 while passing through the slots 114. In an example, the at least two arms 116 may have various cross-sectional shapes, including rectangular, circular, or other geometric 5 profiles, and may have different lengths and widths depending on the spacing requirements and structural considerations.
[0027]
The at least two arms 116 are in a plane different from the plane in which the frame portion 102 lies, creating a three-dimensional structural configuration with various vertical offsets and angular orientations. The 10 frame portion 102 may be positioned in a plane different from the plane in which the terminal portion 108 lies. For example, the plane of the frame portion 102 may be lower than the plane of the terminal portion 108, creating a stepped or tiered configuration that optimizes the spatial arrangement of the current collector plate 100 within the secondary cell. The vertical 15 separation between these planes may vary depending on the specific application requirements and cell design constraints.
[0028]
Furthermore, the current collector plate 100 may include a connection member 118 disposed on the top face 110 of the terminal portion 108. The connection member 118 may be configured to be coupled to a 20 terminal of the secondary battery and is made of a different metal than that of the current collector plate 100. The connection member 118 may be mechanically coupled to the terminal portion 110. In an example, the current collector plate 100 may be made of copper while the connection member 118 may be made of aluminum, thereby providing the benefits of 25 dissimilar metal properties in the electrical connection system. The connection member 118 may have various overall dimensions and configurations to accommodate different terminal designs and connection requirements.
9
[0029]
The connection member 118 may include a base 120 and at least two legs 122 extending away from a periphery of the base 120. The base 120 provides a mounting surface that corresponds to the geometry of the top face 110 of the terminal portion 108, while the legs 122 extend downward to engage with the terminal portion 108 and provide mechanical 5 stability during assembly operations. The base 120 may be the portion of the connection member 118 that is directly coupled to the top face 110 of the terminal portion 108 and may have various thicknesses and surface areas depending on the application requirements. The base 120 may be circular, square, rectangular, or have other geometric configurations. The at 10 least two legs 122 may extend outward from the base 120 at various angles and may have different lengths, widths, and thicknesses. In some embodiments, the at least two legs 122 may be curled or bent towards the bottom face of the terminal portion 108, creating curved or angled configurations that facilitate secure engagement with a terminal of the 15 secondary cell. The at least two legs 122 may be uniformly or non-uniformly spaced around the periphery of the base 120 and may have identical or varying dimensions.
[0030]
FIG. 1B illustrates a cross-sectional view of the current collector plate 100, according to an example of the present subject matter. FIG. 1B 20 provides a detailed cross-sectional perspective of how the connection member 118 is coupled to the terminal portion 108. The sectional view reveals the three-dimensional relationship and mechanical coupling arrangement between these components that may not be fully visible in the top view of FIG. 1A. As shown in FIG. 1B, the connection member 118 is 25 positioned on the top face 110 of the terminal portion 108, with the base 120 of the connection member 118 making direct contact with the top face 110. In an example, the base 120 of the connection member 118 is coupled to the top face 110 of the terminal portion 108 through a coining joint. The base 120 may be configured to conform to the geometry of the top face 110, 30 creating a mating interface that facilitates both electrical and mechanical
10
connection between the connection member 118 and the terminal portion 108. The base 120 may have a thickness that provides structural stability while maintaining efficient electrical conductivity between the dissimilar metals of the connection member 118 and the current collector plate 100.
[0031]
The at least two legs 122 of the connection member 118 extend 5 downward from the periphery of the base 120, wrapping around or engaging with the sides of the terminal portion 108. As depicted in FIG. 1B, the at least two legs 122 are curled towards a bottom face (not shown) of terminal portion 108 to create a secure mechanical coupling. Furthermore, FIG. 1B clearly depicts an interface between the different metals, i.e., the aluminum 10 connection member 118 is mechanically bonded to the copper terminal portion 108. In an example, the legs 122 may extend beyond the bottom face of the terminal portion 108, allowing them to engage with additional terminal components or provide enhanced mechanical stability during assembly operations. 15
[0032]
The sectional view also illustrates a vertical separation between the terminal portion 108 and the frame portion 102, clearly depicting that the terminal portion 108 is positioned in a different plane than the frame portion 102. Further, as is evident from FIG. 1B, the connection member 118 is positioned at the elevated terminal portion 108 while remaining electrically 20 connected to the frame portion 102 through the at least two arms 116.
[0033]
The overall configuration of the current collector plate 100 may provide an efficient current collection system that combines the electrical properties of different metals while maintaining mechanical integrity through the various structural features including the flanges 112, slots 114, arms 25 116, and the mechanically bonded connection member 118 with its base 120 and legs 122 that may be configured in various curled, bent, or extended orientations.
[0034]
FIG. 2 illustrates an exploded view of a secondary battery 200 (hereinafter referred to as a battery 200), according to an example. The 30
11
battery 200 may be a cylindrical battery. The battery 200 includes an electrode assembly 202, such as a jelly roll. The electrode assembly 202 in a cylindrical battery may refer to a coiled structure having alternating layers of a first electrode or anode (not shown) and a second electrode, or a cathode (not shown) separated by a separator layer (not shown) interposed 5 between the first electrode and the second electrode. The anode and the cathode are typically in the form of thin sheets or foils in which the active material, such as anode material and cathode material are coated, and the separator layer is a porous, electrically insulating material that allows ions to pass through while preventing direct contact between the anode and the 10 cathode, which would cause a short circuit.
[0035]
The battery 200 further includes a casing 204 to accommodate the electrode assembly 202. The casing 204 may serve as an outer enclosure and structural support for internal components of the battery 200. The casing 204 may be made of a conductive metal, e.g., aluminum, an 15 aluminum alloy or nickel-coated steel, to provide mechanical protection and electrical conductivity. As depicted in FIG. 2, the casing 204 is formed in a cylindrical shape having a side wall of a predetermined diameter. The material and thickness of the casing 204 may be selected based on factors such as strength, thermal conductivity, and compatibility with a chemistry of 20 the battery 200.The casing 204 has a closed end 206 and an open end (not shown).
[0036]
The electrode assembly 202 is thereafter electrically connected to a current collector plate 208, at one end. The current collector plate 208 may be similar to the current collector plate 100 and therefore, details 25 pertaining to the current collector plate 208 are not described again for the sake of brevity. The current collector plate 208 may act as a bridging component to collect electrical current generated at the electrode assembly 202 and connect with an external terminal. In the present subject matter, the current collector plate 208 is connected to one of the positive electrode 30
12
and the negative electrode. For example, the current collector plate 208 is connected to an uncoated portion of the positive electrode, such as an electrode foil. The current collector plate 208 features a connecting member, similar to the connection member 118, mechanically coupled to the terminal portion. The connection member may be configured to be coupled to a 5 terminal of the battery 200 and may be made of a different metal than that of the current collector plate 208. In an example, the current collector plate 208 may be made of copper while the connection member may be made of aluminum, thereby providing the benefits of dissimilar metal properties in the electrical connection system. 10
[0037]
Such configuration may eliminate bimetal rivet complexity by avoiding traditional dissimilar metal welds between copper and aluminum components. Additionally, the dissimilar metal configuration may provide enhanced thermal management properties, as different metals may have varying thermal expansion coefficients and heat dissipation characteristics 15 that can be leveraged to improve overall battery performance. By providing an aluminum-to-aluminum welding interface at the terminal connection, the design may enable easier and more reliable welding operations with reduced risk of material burning or fusion failures.
[0038]
In addition, an insulating disc or a gasket 210 is mounted on the 20 current collector plate 208, before the electrode assembly 202 is inserted inside the casing 202 through the open end. The insulating disc 210 is disposed between the current collector plate 208 and an inner surface of the closed end 204 of the casing 202. Further, the open end of the casing 202 is closed with a bottom plate (not shown) to hold the electrode assembly 25 202 in the casing 202. The bottom plate is attached with the casing 202 in such a manner that the bottom plate is in contact with the negative electrode of the electrode assembly 202. As a circumferential edge of the bottom plate is aligned with the side wall of the casing 202, the casing 202 acts as a negative terminal of the battery 200. 30
13
[0039]
In addition, the battery 200 includes a rivet 212 attached to the closed end 204 of the casing 202 through a rivet gasket 214. The rivet 212 is welded to the current collector plate 208. As a result, the rivet 212 acts as a positive terminal of the battery 200. The rivet gasket 214 provides a hermetic sealing between the rivet 212 and the closed end 204 of the casing 5 202. The rivet gasket 214 provides electrical insulation between opposite terminals of the battery 200. As may be appreciated, the current collector plate 208 may provide a shorter current flow path through the rivet 212. Thus, the current collector plate 208 may help to lower the internal resistance of the battery 200 which may improve charging and discharging 10 efficiency of the battery 200.
[0040]
FIG. 3 illustrates a cross-sectional view of a secondary battery 300, according to an example. The secondary battery 300 includes a casing 302, which serves as the structural enclosure for the internal components of the secondary battery 300. The casing 302 may be cylindrical in shape 15 and may be made of a conductive metal such as aluminum, an aluminum alloy, or nickel-coated steel to provide mechanical protection and electrical conductivity. The casing 302 is similar to the casing 202 described with respect to FIG. 2. The secondary battery 300 further includes an electrode assembly 304 accommodated within the casing 302. The electrode 20 assembly 304 is similar to the electrode assembly 202 and may comprise a jelly roll configuration that includes active materials of the secondary battery 300, including the cathode, anode, and separator layers, which are wound together in a spiral arrangement to maximize surface area within the confined space of the casing 302. 25
[0041]
The secondary battery 300 may include a current collector plate 306 positioned above and electrically connected to the electrode assembly 304. The current collector plate 306 may be welded or otherwise mechanically and electrically coupled to the electrode assembly 304 to facilitate current collection from the active materials. The current collector 30
14
plate 306 is integrated with a connection member 308 for use in cylindrical cells with reverse terminal architecture, such as Lithium Iron Phosphate (LFP) cells. The copper current collector plate 306 with an aluminum connection member 308 are strategically positioned at a terminal interface zone to facilitate aluminum-to-aluminum welding with a rivet 310. The 5 connection member 308 may be disposed on a top surface of the current collector plate 306 and may cover a central portion of the current collector plate 306 where terminal connection is required.
[0042]
In an example, the connection member 308 is mechanically bonded to the current collector plate 306 through a combination of stamping, 10 edge curling, and coining processes that create a robust mechanical and electrical interface between the dissimilar metals. The coining operation creates a thickness reduction in a center region, where a thickness of the connection member 308 is reduced from approximately 0.5 mm to 0.3 mm, while the underlying current collector plate 306 is compressed from 0.2 mm 15 to 0.1 mm thickness. This compression creates a strong mechanical joint between the dissimilar metals through applied stress in the thickness direction, ensuring reliable electrical conductivity and mechanical stability under various operating conditions including thermal cycling and mechanical vibration. 20
[0043]
The edge curling feature secures the connection member 308 around the periphery of a welding zone, ensuring reliable structural and electrical bonding between the copper and aluminum layers. The welding zone represents the area where the connection member 308 and the rivet 310 are joined together through welding processes. The edge curling may 25 involve bending or folding the edges of the connection member 308 to create a mechanical interlock with the current collector plate 306, thereby preventing delamination or separation of the layers during battery operation. The connection member 308, composed of AL1060 grade aluminum or similar aluminum alloy, may extend beyond a surface of the copper current 30
15
collector plate 306 in a terminal contact area, providing a clean aluminum-to-aluminum interface for welding with the aluminum rivet 310.
[0044]
The rivet 310 extends through the connection member 308 and the current collector plate 306, creating a continuous electrical path from the electrode assembly 304 to an external terminal of the secondary battery 5 300. The rivet 310 may be made of aluminum or aluminum alloy to match the material properties of the connection member 308, thereby facilitating compatible welding characteristics and reducing the risk of galvanic corrosion. A rivet gasket 312 may be positioned adjacent to the rivet 310 to provide sealing functionality and electrical insulation between components. 10 The welding zone formed between the connection member 308 and the rivet 310 may be created using standard aluminum welding techniques such as resistance welding, laser welding, or ultrasonic welding, which are well-established processes with high reliability and repeatability.
[0045]
This configuration eliminates the need for expensive bimetallic 15 rivets and avoids the welding challenges associated with copper-to-copper fusion, which typically requires high-temperature laser welding processes and results in only 60% weld quality yield due to the high thermal conductivity and melting point of copper. The connection member 308 may enable standard aluminum welding techniques, reducing manufacturing 20 complexity and material costs by approximately 80% compared to copper rivet alternatives. The aluminum-to-aluminum welding interface may also provide improved weld quality and consistency, leading to better electrical performance and longer battery life.
[0046]
The dimensional specifications of the current collector plate 306 25 and connection member 308 may include the overall diameter of the current collector plate 306, which may be sized to correspond with the diameter of the electrode assembly 304 and the internal dimensions of the casing 302. The thickness of both the copper base material of the current collector plate 306 and the aluminum overlay of the connection member 308 may be 30
16
optimized to provide adequate electrical conductivity while minimizing material usage and weight. The diameter and depth of the central rivet connection zone may be designed to accommodate the rivet 310 and ensure proper mechanical engagement and electrical contact. The geometric profile of the edge curling feature may be precisely controlled to 5 achieve optimal bonding strength between the connection member 308 and the current collector plate 306. These precise dimensions ensure proper electrical conductivity, mechanical stability, and optimal integration within the secondary battery 300, particularly for reverse terminal LFP cylindrical cell applications where the anode terminal is positioned toward the rivet side 10 of the cell, contrary to conventional battery designs where the cathode terminal is typically positioned at the rivet end.
[0047]
FIG. 4A illustrates a perspective view of a current collector plate 400, in accordance with another example of the present subject matter. The current collector plate 400 is configured for being connected to an electrode 15 assembly (not shown) of a secondary battery and facilitate efficient electrical connectivity and mechanical coupling. In an example, the current collector plate 400 may function as either an anode current collector or a cathode current collector depending on the specific battery configuration and application requirements. 20
[0048]
The current collector plate 400 includes a frame portion 402 for coupling with an electrode assembly of the secondary battery. The frame portion 402 provides structural support and coupling interface for the current collector plate 400 within a battery. The frame portion 402 may have a configuration that corresponds to the geometry of the electrode assembly, 25 allowing the current collector plate 400 to interface with and secure the electrode assembly within the secondary battery. The frame portion 402 may adopt various shapes including circular, annular, polygonal, or other geometric configurations depending on the specific design requirements and spatial constraints of the secondary battery. The configuration of the 30
17
frame portion 402 may be adapted to match the outer periphery or structural characteristics of the electrode assembly, ensuring optimal mechanical coupling and electrical connectivity between these components.
[0049]
In the illustrated embodiment, the frame portion 402 may define an outer periphery and an inner periphery, with the inner periphery providing 5 the primary coupling interface for the electrode assembly. The frame portion 402 may be a substantially flat, conductive plate that forms a primary electrical connection between the electrode assembly and an external circuit of the secondary cell. The frame portion 402 may be made from a conductive material, such as copper, aluminum, nickel, or other suitable 10 metals or alloys to provide low electrical resistance and adequate thermal conductivity for efficient current collection and heat dissipation.
[0050]
The current collector plate 400 further includes a terminal portion 404 coupled to and spaced apart from the frame portion 402. The terminal portion 404 is positioned centrally relative to the frame portion 402 and 15 configured to provide a dedicated platform for establishing electrical connectivity with external terminal components. The terminal portion 404 has a substantially circular configuration and is formed as a raised or elevated region that extends upward from the general plane of the frame portion 402. The terminal portion 404 may be created through stamping, 20 coining, or other forming processes that shape the copper material to create the desired three-dimensional geometry
[0051]
The terminal portion 404 includes a top face 406 that forms the uppermost surface of the raised circular region. The top face 406 may be substantially planar and oriented parallel to the general plane of the frame 25 portion 402, creating a stable mounting platform for connection components. The top face 406 is positioned at an elevated height relative to the surrounding frame portion 402, which facilitates proper alignment and engagement with rivet components or other terminal hardware during assembly operations. In an example, the terminal portion 404 may be 30
18
integrally formed with the frame portion 402 or may be separately manufactured and subsequently joined through welding, brazing, mechanical fastening, or other suitable joining methods.
[0052]
Further, the current collector plate 400 include a connection member 408 is disposed on the top face 406 of the terminal portion 404 for 5 being coupled to a terminal of the secondary battery. The connection member 408 has a substantially circular or disc-like shape and is positioned concentrically with respect to the terminal portion 404. The connection member 408 may cover a central region of the top face 406 where terminal connection is required. The circular configuration of the connection member 10 408 provides uniform contact area and stress distribution when interfacing with cylindrical rivet components or other circular terminal elements.
[0053]
The connection member 408 may be mechanically coupled to the terminal portion 404. For example, the connection member 408 may be coupled to the top face 406 of the terminal portion 404 through various 15 attachment methods including a coining joint, stamping, or other mechanical bonding processes. The connection member 408 is made of a different metal than that of the current collector plate 408. For example, the connection member 408 may be made of aluminum material while the underlying current collector plate 400 is made of copper, providing the 20 benefits of dissimilar metal properties in the electrical connection system. The aluminum connection member 408 enables compatible welding characteristics with aluminum rivet components, thereby facilitating easier and more reliable welding operations compared to copper-to-aluminum or copper-to-copper welding configurations. 25
[0054]
The circular shape of the connection member 408 corresponds to the geometry of standard rivet heads and welding interfaces commonly used in cylindrical battery applications. This configuration ensures optimal contact area and mechanical stability during welding operations while providing uniform current distribution across the connection interface. The 30
19
connection member 408 may be sized to match the diameter of the rivet head or welding zone to maximize the effectiveness of the electrical and mechanical connection between the current collector plate 400 and the terminal system. In some embodiments, the connection member 408 may include raised features, recessed areas, or textured surfaces that facilitate 5 mechanical engagement with terminal components or provide enhanced electrical contact areas.
[0055]
The current collector plate 400 may be manufactured using various forming processes including stamping, machining, casting, or additive manufacturing techniques. The frame portion 402 and terminal 10 portion 404 may be formed as a single integral component or may be manufactured separately and subsequently joined. The aluminum sheet layer 408 may be applied during the manufacturing process or may be added as a post-processing step through various bonding or attachment methods. 15
[0056]
FIG. 4B illustrates a cross-sectional view of the current collector plate 400, according to another example of the present subject matter. FIG. 4B provides a detailed cross-sectional perspective of how the connection member 408 is coupled to the terminal portion 404, thereby revealing the three-dimensional relationship and mechanical coupling arrangement 20 between the terminal portion 404 and the connection member 408. As shown in FIG. 4B, the connection member 408 is positioned on the top face 406 of the terminal portion 404, with the connection member 408 making direct contact with the top face 406. The connection member 408 may be configured to conform to the geometry of the top face 406, creating a mating 25 interface that facilitates both electrical and mechanical connection between the connection member 408 and the terminal portion 404.
[0057]
In an example, the connection member 408 may have a thickness that provides structural stability while maintaining efficient electrical conductivity between the dissimilar metals of the connection member 408 30
20
and the current collector plate 400. The connection member 408 may be configured as a substantially planar disc or circular element that is positioned directly on the top face 406, creating a uniform bonding interface across the contact area. Furthermore, FIG. 4B clearly depicts an interface between the different metals, i.e., the aluminum connection member 408 is 5 mechanically bonded to the copper terminal portion 404. In an example, the connection member 408 may be coined to the top face 406, allowing for enhanced electrical connectivity and mechanical stability during assembly operations.
[0058]
FIG. 4B also illustrates a vertical separation between the terminal 10 portion 404 and the frame portion 402, clearly depicting that the terminal portion 404 is positioned in a different plane than the frame portion 402. Further, as is evident from FIG. 4B, the connection member 408 is positioned at the elevated terminal portion 404 while remaining electrically connected to the frame portion 402 through the structural continuity of the 15 current collector plate 400.
[0059]
The overall configuration of the current collector plate 400 may provide an efficient current collection system that combines the electrical properties of different metals while maintaining mechanical integrity and structural stability within the secondary battery. The combination of the 20 frame portion 402, terminal portion 404, and aluminum sheet layer 408 creates a multi-material system that may optimize electrical performance, mechanical durability, and manufacturing efficiency for various battery applications and configurations.
[0060]
FIG. 5 illustrates an exploded view of a secondary battery 500 25 (hereinafter referred to as battery 500), according to an example. The battery 500 may be a cylindrical battery. The battery 500 includes an electrode assembly 502, such as a jelly roll. The electrode assembly 502 in a cylindrical battery may refer to a coiled structure having alternating layers of a first electrode or anode (not shown) and a second electrode, or a 30
21
cathode (not shown) separated by a separator layer (not shown) interposed between the first electrode and the second electrode. The anode and the cathode are typically in the form of thin sheets or foils in which the active material, such as anode material and cathode material are coated, and the separator layer is a porous, electrically insulating material that allows ions 5 to pass through while preventing direct contact between the anode and the cathode, which would cause a short circuit.
[0061]
The battery 500 further includes a casing 504 to accommodate the electrode assembly 502. The casing 504 may serve as an outer enclosure and structural support for internal components of the battery 500. 10 The casing 504 may be made of a conductive metal, e.g., aluminum, an aluminum alloy or nickel-coated steel, to provide mechanical protection and electrical conductivity. The casing 504 is formed in a cylindrical shape having a side wall of a predetermined diameter. The material and thickness of the casing 504 may be selected based on factors such as strength, 15 thermal conductivity, and compatibility with a chemistry of the battery 500. The casing 504 has a closed end 506 and an open end (not shown).
[0062]
The electrode assembly 502 is thereafter electrically connected to a current collector plate 508, at one end. The current collector plate 508 may be similar to the current collector plate 400 and therefore, details 20 pertaining to the current collector plate 508 are not described again for the sake of brevity. The current collector plate 508 may act as a bridging component to collect electrical current generated at the electrode assembly 502 and connect with external terminals. In the present subject matter, the current collector plate 508 is connected to one of the positive electrode and 25 the negative electrode. For example, the current collector plate 508 is connected to an uncoated portion of the positive electrode, such as an electrode foil. The current collector plate 508 features a connection member, similar to the connection member 408, mechanically coupled to a terminal portion of the current collector plate 508. The connection member 30
22
may be configured to be coupled to a terminal of the battery 500 and may be made of a different metal than that of the current collector plate 508. In an example, the current collector plate 508 may be made of copper while the connection member may be made of aluminum, thereby providing the benefits of dissimilar metal properties in the electrical connection system. In 5 an example, the connection member is coupled to a top face of the terminal portion of the current collector plate 508 by a coining joint.
[0063]
Such configuration may eliminate bimetal rivet complexity by avoiding traditional dissimilar metal welds between copper and aluminum components. Additionally, the dissimilar metal configuration may provide 10 enhanced thermal management properties, as different metals may have varying thermal expansion coefficients and heat dissipation characteristics that can be leveraged to improve overall battery performance. By providing aluminum-to-aluminum welding interfaces at the terminal connections, the design may enable easier and more reliable welding operations with 15 reduced risk of material burning or fusion failures. The multiple connection member configuration may also provide improved mechanical stability and reliability compared to single-point connection systems, while enabling better load distribution across the current collector plate 508, potentially reducing stress concentrations that could lead to mechanical failure during 20 battery operation or thermal cycling.
[0064]
In addition, an insulating disc or a gasket 510 is mounted on the current collector plate 508, before the electrode assembly 506 is inserted inside the casing 502 through the open end. The insulating disc 510 is disposed between the current collector plate 508 and an inner surface of 25 the closed end 504 of the casing 502. Further, the open end of the casing 502 is closed with a bottom plate (not shown) to hold the electrode assembly 506 in the casing 502. The bottom plate is attached with the casing 502 in such a manner that the bottom plate is in contact with the negative electrode of the electrode assembly 506. As a circumferential edge of the bottom plate 30
23
is aligned with the side wall of the casing 502, the casing 502 acts as a negative terminal of the battery 500.
[0065]
In addition, the battery 500 includes rivets 512 attached to the closed end 504 of the casing 502. The rivets 512 are welded to the current collector plate 508 at multiple locations. As a result, the rivets 512 5 collectively act as positive terminals of the battery 500, providing multiple connection points for external electrical connections. The multiple rivet configuration may provide electrical insulation between opposite terminals of the battery 500 while enabling distributed current collection. As may be appreciated, the current collector plate 508 may provide multiple shorter 10 current flow paths through the rivets 512. Thus, the current collector plate 508 may help to lower the internal resistance of the battery 500 which may improve charging and discharging efficiency of the battery 500.
[0066]
FIG. 6 illustrates a cross-sectional view of a secondary battery 600, according to an example. The secondary battery 600 includes a casing 15 602, which serves as the structural enclosure for the internal components of the secondary battery 600. The casing 602 may be cylindrical in shape and may be made of a conductive metal such as aluminum, an aluminum alloy, or nickel-coated steel to provide mechanical protection and electrical conductivity. The casing 602 may be similar to the casings described with 20 respect to previous figures and may provide structural support and electrical connectivity for the secondary battery.
[0067]
The secondary battery 600 further includes an electrode assembly 604 accommodated within the casing 602. The electrode assembly 604 may comprise a jelly roll configuration that includes active 25 materials of the secondary battery 600, including the cathode, anode, and separator layers, which are wound together in a spiral arrangement to maximize surface area within the confined space of the casing 602. The electrode assembly 604 may be similar to the electrode assemblies
24
described in previous embodiments and may provide the electrochemical functionality for energy storage and release.
[0068]
The secondary battery 600 may include a current collector plate 606 positioned above and electrically connected to the electrode assembly 604. The current collector plate 606 may be welded or otherwise 5 mechanically and electrically coupled to the electrode assembly 604 to facilitate current collection from the active materials. The current collector plate 606 may be similar to the current collector plate 400 described with respect to FIG. 4 and may include a frame portion and terminal portion configured to interface with the electrode assembly 604 and external 10 terminal components. In an example, the current collector plate 606 may be made of copper (T2 grade) to provide optimal electrical conductivity for current collection.
[0069]
As illustrated in FIG. 6, a connection member 608 is disposed on a top surface of the current collector plate 606. The connection member 608 15 may cover a central portion of the current collector plate 606 where terminal connection is required and may be made of a different metal than the current collector plate 606. In an example, the current collector plate 606 may be made of copper while the connection member 608 may be made of aluminum, providing the benefits of dissimilar metal properties in the 20 electrical connection system. For example, the connection member 608 may be made of aluminum material (AL1060 H14 grade) and has a diameter of approximately 20 mm and an initial thickness of approximately 0.5 mm. The connection member 608 may be mechanically bonded to the current collector plate 606, such as through coining process. In an example, after 25 the coining process, the thickness of the connection member 608 is reduced to approximately 0.3 mm in the central region, while a thickness of the underlying current collector plate 606 is reduced from approximately 0.2 mm to 0.1 mm in the coined area.
25
[0070]
The secondary battery 600 further includes a rivet 610 that extends through the connection member 608 and the current collector plate 606, creating a continuous electrical path from the electrode assembly 604 to an external terminal of the secondary battery 600. The rivet 610 may be made of aluminum or aluminum alloy to match the material properties of the 5 connection member 608, thereby facilitating compatible welding characteristics and reducing the risk of galvanic corrosion between dissimilar metals. Further, a rivet gasket 612 may be positioned adjacent to the rivet 610 to provide sealing functionality and electrical insulation between components. The rivet gasket 612 may be made of an insulating 10 material such as rubber, plastic, or other suitable sealing materials to prevent electrical short circuits and provide environmental protection.
[0071]
In an example, a welding zone may be formed between the connection member 608 and the rivet 610. For instance, the welding zone may represent the area where the connection member 608 and the rivet 610 15 are joined together through welding processes. The welding zone may be created using standard aluminum welding techniques such as resistance welding, laser welding, or ultrasonic welding, which may provide reliable and repeatable joining characteristics. The aluminum-to-aluminum interface at the welding zone may enable easier and more reliable welding operations 20 compared to copper-to-aluminum or copper-to-copper welding configurations, potentially reducing manufacturing complexity and improving weld quality consistency.
[0072]
The configuration shown in FIG. 6 may provide enhanced electrical performance and manufacturing efficiency by eliminating the need 25 for expensive bimetallic rivets and avoiding the welding challenges associated with dissimilar metal fusion. The connection member 608 may enable standard aluminum welding techniques while maintaining the electrical conductivity benefits of the copper current collector plate 606,
26
creating an optimized multi-material system for current collection and terminal connection applications in cylindrical battery cells.
[0073]
Although examples for the present disclosure have been described in language specific to structural features and/or methods, it is to be understood that these examples are not necessarily limited to the specific 5 features or methods described. Rather, the specific features and methods are disclosed and explained as examples of the present description.
10
27
I/We Claim:
1. A current collector plate (100, 208, 306, 400, 508, 606) for being connected to an electrode assembly (202, 304, 502, 604) of a secondary battery (200, 300, 500, 600), the current collector plate (100, 208, 306, 400, 5 508, 606) comprising:
a frame portion (102, 402) for coupling with the electrode assembly (202, 304, 502, 604);
a terminal portion (108, 404) coupled to and spaced apart from the frame portion (102, 402), the terminal portion (108, 404) comprises a top 10 face (110, 406); and
a connection member (118, 308, 408, 608), disposed on the top face (110, 406) of the terminal portion (108, 404), for being coupled to a terminal of the secondary battery (200, 300, 500, 600), wherein the connection member (118, 308, 408, 608) is made of a different metal than that of the 15 current collector plate (100, 208, 306, 400, 508, 606).
2. The current collector plate (100, 208, 306, 400, 508, 606) as claimed in claim 1, wherein the current collector plate (100, 208, 306, 400, 508, 606) is made of Copper and the connection member (118, 308, 408, 608) is made of Aluminum. 20
3. The current collector plate (100, 208, 306, 400, 508, 606) as claimed in claim 1, wherein the connection member (118, 308, 408, 608) is mechanically coupled to the terminal portion (108, 404).
4. The current collector plate plate (100, 208, 306, 400, 508, 606) as claimed in claim 3, wherein the connection member (408, 608) is coupled to the top 25 face (406) of the terminal portion (404) through a coining joint.
5. The current collector plate (100, 208, 306) as claimed in claim 1, wherein the current collector plate (100, 208, 306) comprises:
28
at least two flanges (112) extending from an inner periphery (106) of the frame portion (102) to create two or more slots (114) in the frame portion (102); and
at least two arms (116) positioned in the two or more slots (114) and converging from the inner periphery (106) of the frame portion (102) towards 5 a center of the frame portion (102) to connect the terminal portion (108) with the frame portion (102), wherein the at least two arms (116) are spaced apart from the at least two flanges (112).
6. The current collector plate (100, 208, 306) as claimed in claim 5, wherein the at least two arms (116) are in a plane different from the plane in which 10 the frame portion (102) lies.
7. The current collector plate (100, 208, 306) as claimed in claim 5, wherein the frame portion (102) is in a plane different from the plane in which the terminal portion (108) lies.
8. The current collector plate (100, 208, 306) as claimed in claim 7, wherein 15 the plane of the frame portion (102) is lower than the plane of the terminal portion (108).
9. The current collector plate (100, 208, 306) as claimed in claim 5, wherein the connection member (118) comprises a base (120) and at least two legs (122) extending away from a periphery of the base (120). 20
10. The current collector plate (100, 208, 306) as claimed in claim 9, wherein the base (120) of the connection member (118) is coupled to the top face (110) through a coining joint.
11. The current collector plate (100, 208, 306) as claimed in claim 10, wherein the at least two legs (122) are curled towards a bottom face of the 25 terminal portion (108).
12. A secondary battery (200, 300, 500, 600) comprising:
29
an electrode assembly (202, 304, 502, 604) comprising a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode;
a casing (104, 504) to accommodate the electrode assembly ; and
a current collector plate (100, 208, 306, 400, 508, 606) connected to 5 one of the positive electrode and the negative electrode, wherein the current collector plate comprises:
a frame portion (102, 402) coupled with the electrode assembly (202, 304, 502, 604);
a terminal portion (108, 404) coupled to and spaced apart from 10 the frame portion (102, 402), the terminal portion (108, 404) comprises a top face (110, 406); and
a connection member (118, 308, 408, 608), disposed on the top face (110, 406) of the terminal portion (108, 404), to connect to a terminal of the secondary battery (200, 300, 500, 600), wherein the 15 connection member (118, 308, 408, 608) is made of a different metal than that of the current collector plate (100, 208, 306, 400, 508, 606).
13. The secondary battery (200, 300, 500, 600) as claimed in claim 12, wherein the current collector plate (100, 208, 306, 400, 508, 606) is made of Copper and the connection member (118, 308, 408, 608) is made of 20 Aluminum.
14. The secondary battery (200, 300, 500, 600) as claimed in claim 12, wherein the connection member (118, 308, 408, 608) is mechanically bonded to the terminal portion (108, 404).
15. The secondary battery (200, 300, 500, 600) as claimed in claim 14, 25 wherein the connection member (118, 308, 408, 608) is coupled to the top surface of the terminal portion (108, 404) through a coining joint.
16. The secondary battery (200, 300) as claimed in claim 12, wherein the current collector plate (100, 208, 306) comprises:
30
at least two flanges (112) extending from an inner periphery (106) of the frame portion (102) to create two or more slots (114) in the frame portion (102); and
at least two arms (116) positioned in the two or more slots (114) and converging from the inner periphery (106) of the frame portion (102) towards 5 a center of the frame portion (102) to connect the terminal portion (108) with the frame portion (102), wherein the at least two arms (116) are spaced apart from the at least two flanges (112).
17. The secondary battery (200, 300) as claimed in claim 16, wherein the at least two arms (116) are in a plane different from the plane in which the 10 frame portion (102) lies.
18. The secondary battery (200, 300) as claimed in claim 17, wherein the frame portion (102) is in a plane different from the plane in which the terminal portion (108) lies.
19. The secondary battery (200, 300) as claimed in claim 18, wherein a 15 plane of the frame portion (102) is lower than the plane of the terminal portion (108).
20. The secondary battery (200, 300) as claimed in claim 16, wherein the connection member (118, 308) comprises a base (120) and at least two legs (122, 310) extending away from a periphery of the base (120). 20
21. The secondary battery (200, 300) as claimed in claim 20, wherein the base (120) of the connection member (108, 308) is coupled to the top face (110) through coining.
22. The secondary battery (200, 300) as claimed in claim 20, wherein the at least two legs (122, 310) are curled towards the bottom face of the terminal 25 portion (108).
31
ABSTRACT
CURRENT COLLECTOR PLATES FOR SECONDARY CELLS
Example current collector plates (100, 208, 306, 400, 508, 606) for being connected to an electrode assembly (202, 304, 502, 604) of a 5 secondary battery (200, 300, 500, 600) are described. The current collector plate (100, 208, 306, 400, 508, 606) comprises a frame portion (102, 402) for coupling with the electrode assembly (202, 304, 502, 604) and a terminal portion (108, 404) coupled to and spaced apart from the frame portion (102, 402). The terminal portion (108, 404) comprises a top face (110, 406). 10 Further, the current collector plate (100, 208, 306, 400, 508, 606) comprises a connection member (118, 308, 408, 608), disposed on the top face (110, 406) of the terminal portion (108, 404), for being coupled to a terminal of the secondary battery. The connection member (118, 308, 408, 608) is made of a different metal than that of the current collector plate. 15
<> , Claims:I/We Claim:
1. A current collector plate (100, 208, 306, 400, 508, 606) for being connected to an electrode assembly (202, 304, 502, 604) of a secondary battery (200, 300, 500, 600), the current collector plate (100, 208, 306, 400, 5 508, 606) comprising:
a frame portion (102, 402) for coupling with the electrode assembly (202, 304, 502, 604);
a terminal portion (108, 404) coupled to and spaced apart from the frame portion (102, 402), the terminal portion (108, 404) comprises a top 10 face (110, 406); and
a connection member (118, 308, 408, 608), disposed on the top face (110, 406) of the terminal portion (108, 404), for being coupled to a terminal of the secondary battery (200, 300, 500, 600), wherein the connection member (118, 308, 408, 608) is made of a different metal than that of the 15 current collector plate (100, 208, 306, 400, 508, 606).
2. The current collector plate (100, 208, 306, 400, 508, 606) as claimed in claim 1, wherein the current collector plate (100, 208, 306, 400, 508, 606) is made of Copper and the connection member (118, 308, 408, 608) is made of Aluminum. 20
3. The current collector plate (100, 208, 306, 400, 508, 606) as claimed in claim 1, wherein the connection member (118, 308, 408, 608) is mechanically coupled to the terminal portion (108, 404).
4. The current collector plate plate (100, 208, 306, 400, 508, 606) as claimed in claim 3, wherein the connection member (408, 608) is coupled to the top 25 face (406) of the terminal portion (404) through a coining joint.
5. The current collector plate (100, 208, 306) as claimed in claim 1, wherein the current collector plate (100, 208, 306) comprises:
28
at least two flanges (112) extending from an inner periphery (106) of the frame portion (102) to create two or more slots (114) in the frame portion (102); and
at least two arms (116) positioned in the two or more slots (114) and converging from the inner periphery (106) of the frame portion (102) towards 5 a center of the frame portion (102) to connect the terminal portion (108) with the frame portion (102), wherein the at least two arms (116) are spaced apart from the at least two flanges (112).
6. The current collector plate (100, 208, 306) as claimed in claim 5, wherein the at least two arms (116) are in a plane different from the plane in which 10 the frame portion (102) lies.
7. The current collector plate (100, 208, 306) as claimed in claim 5, wherein the frame portion (102) is in a plane different from the plane in which the terminal portion (108) lies.
8. The current collector plate (100, 208, 306) as claimed in claim 7, wherein 15 the plane of the frame portion (102) is lower than the plane of the terminal portion (108).
9. The current collector plate (100, 208, 306) as claimed in claim 5, wherein the connection member (118) comprises a base (120) and at least two legs (122) extending away from a periphery of the base (120). 20
10. The current collector plate (100, 208, 306) as claimed in claim 9, wherein the base (120) of the connection member (118) is coupled to the top face (110) through a coining joint.
11. The current collector plate (100, 208, 306) as claimed in claim 10, wherein the at least two legs (122) are curled towards a bottom face of the 25 terminal portion (108).
12. A secondary battery (200, 300, 500, 600) comprising:
29
an electrode assembly (202, 304, 502, 604) comprising a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode;
a casing (104, 504) to accommodate the electrode assembly ; and
a current collector plate (100, 208, 306, 400, 508, 606) connected to 5 one of the positive electrode and the negative electrode, wherein the current collector plate comprises:
a frame portion (102, 402) coupled with the electrode assembly (202, 304, 502, 604);
a terminal portion (108, 404) coupled to and spaced apart from 10 the frame portion (102, 402), the terminal portion (108, 404) comprises a top face (110, 406); and
a connection member (118, 308, 408, 608), disposed on the top face (110, 406) of the terminal portion (108, 404), to connect to a terminal of the secondary battery (200, 300, 500, 600), wherein the 15 connection member (118, 308, 408, 608) is made of a different metal than that of the current collector plate (100, 208, 306, 400, 508, 606).
13. The secondary battery (200, 300, 500, 600) as claimed in claim 12, wherein the current collector plate (100, 208, 306, 400, 508, 606) is made of Copper and the connection member (118, 308, 408, 608) is made of 20 Aluminum.
14. The secondary battery (200, 300, 500, 600) as claimed in claim 12, wherein the connection member (118, 308, 408, 608) is mechanically bonded to the terminal portion (108, 404).
15. The secondary battery (200, 300, 500, 600) as claimed in claim 14, 25 wherein the connection member (118, 308, 408, 608) is coupled to the top surface of the terminal portion (108, 404) through a coining joint.
16. The secondary battery (200, 300) as claimed in claim 12, wherein the current collector plate (100, 208, 306) comprises:
30
at least two flanges (112) extending from an inner periphery (106) of the frame portion (102) to create two or more slots (114) in the frame portion (102); and
at least two arms (116) positioned in the two or more slots (114) and converging from the inner periphery (106) of the frame portion (102) towards 5 a center of the frame portion (102) to connect the terminal portion (108) with the frame portion (102), wherein the at least two arms (116) are spaced apart from the at least two flanges (112).
17. The secondary battery (200, 300) as claimed in claim 16, wherein the at least two arms (116) are in a plane different from the plane in which the 10 frame portion (102) lies.
18. The secondary battery (200, 300) as claimed in claim 17, wherein the frame portion (102) is in a plane different from the plane in which the terminal portion (108) lies.
19. The secondary battery (200, 300) as claimed in claim 18, wherein a 15 plane of the frame portion (102) is lower than the plane of the terminal portion (108).
20. The secondary battery (200, 300) as claimed in claim 16, wherein the connection member (118, 308) comprises a base (120) and at least two legs (122, 310) extending away from a periphery of the base (120). 20
21. The secondary battery (200, 300) as claimed in claim 20, wherein the base (120) of the connection member (108, 308) is coupled to the top face (110) through coining.
22. The secondary battery (200, 300) as claimed in claim 20, wherein the at least two legs (122, 310) are curled towards the bottom face of the terminal 25 portion (108).