A secondary battery with favorable cycle performance is provided. Alternatively, a secondary battery with higher capacity is provided. A positive electrode active material layer including a first graphene layer, a second graphene layer, and a positive electrode active material. The first graphene layer includes a first region covering the positive electrode active material. The second graphene layer includes a second region covering the positive electrode active material and a third region overlapping with the first region. The first region includes a plane positioned between the positive electrode active material and the third region and formed of arranged six-membered carbon rings. The positive electrode active material includes a fourth region with a layered rock-salt structure. A lithium layer with a layered rock-salt structure included in the fourth region is substantially perpendicular to the plane formed of six-membered carbon rings and included in the second region.

Provided is a secondary battery including an electrode assembly and an outer case configured to house the electrode assembly. The secondary battery includes a terminal member provided on the outer case with an insulating material interposed therebetween and connected to a tab of the electrode assembly. The outer case is provided with a cavity through which the tab passes, the terminal member is bonded onto a surface of the outer case with the insulating material interposed therebetween, the surface being positioned around the cavity, and a part of a width dimension of a bonding region provided to surround the cavity for the bonding is reduced.

A lithium-sulfur battery includes a casing, a top lid circumferentially welded to the casing, a negative contact surface positioned opposite the top lid, a positive terminal disposed within the casing, welded to the top lid, and configured as a mandrel, a glass insulator circumferentially wound around the mandrel, and a jelly roll including at least an anode and a cathode wound around the mandrel. The jelly roll may also include a top surface not in contact with the top lid, a bottom surface partially in contact with the negative contact surface, and partially in contact with a plurality of non-hollow carbonaceous spherical particles disposed between the bottom surface of the jelly roll and the negative contact surface. At least some of the non-hollow carbonaceous spherical particles may provide one or more electrically-conductive pathways between the bottom surface and the negative contact surface.

A battery header cap and an assembly method thereof are provided, and the battery header cap includes a battery, a battery header, an insulating sleeve, and a header cap. The battery includes a battery body and a battery case, and the battery case has a header groove near a case opening. The battery header is disposed at the case opening, and the insulating sleeve completely covers the metal surface of the battery header cap. The header cap includes an electrode plane and a sidewall, the electrode plane has a header cap opening to expose the metal electrode, the electrode plane is disposed on the insulating sleeve, the sidewall covers the end of the battery case, and the end of the sidewall is embedded into the header groove. The structure provides support and insulating protection for the header and also enhances the sealability of the case.

A battery header cap and an assembly method thereof are provided, and the battery header cap includes a battery, a battery header, an insulating sleeve, and a header cap. The battery includes a battery body and a battery case, and the battery case has a header groove near a case opening. The battery header is disposed at the case opening, and the insulating sleeve completely covers the metal surface of the battery header cap. The header cap includes an electrode plane and a sidewall, the electrode plane has a header cap opening to expose the metal electrode, the electrode plane is disposed on the insulating sleeve, the sidewall covers the end of the battery case, and the end of the sidewall is embedded into the header groove. The structure provides support and insulating protection for the header and also enhances the sealability of the case.

A terminal assembly includes a male terminal structure and a female terminal structure. The male terminal structure includes a male terminal body, a first terminal member, and a free terminal member. The first terminal member is disposed at the male terminal body. The free terminal member is disposed at the male terminal body and detachably in contact with the first terminal member. The female terminal structure includes a female terminal body, an extension portion, a tunnel, a second terminal member, and a secured terminal member. The extension portion is protruding from the female terminal body. The tunnel is recessed from the extension portion. The second terminal member is disposed at the female terminal body and received in the tunnel. The secured terminal member is disposed at the female terminal body, spaced from the second terminal member, and disposed on the extension portion.

A rechargeable lithium battery including an electrode assembly includes a positive electrode including a positive current collector and a positive active material layer disposed on the positive current collector; a negative electrode including a negative current collector, a negative active material layer disposed on the negative current collector, and a negative electrode functional layer disposed on the negative active material layer; and a separator, wherein the positive active material layer includes a first positive active material including at least one of a composite oxide of metal selected from cobalt, manganese, nickel, and a combination thereof and lithium and a second positive active material including a compound represented by Chemical Formula 1, the negative electrode functional layer includes flake-shaped polyethylene particles, and a battery capacity is greater than or equal to about 3.5 Ah.
Li.sub.aFe.sub.1−x1M.sub.x1PO.sub.4  [Chemical Formula 1] In Chemical Formula 1, 0.90≤a≤1.8, 0≤x1≤0.7, and M is Mn, Co, Ni, or a combination thereof.

An energy storage device includes: an external terminal having any one of positive and negative polarities and including a protrusion and a first terminal; a case having a polarity opposite to the external terminal and including an extension; a substrate disposed to surround an outer circumference of the protrusion of the external terminal through a hole formed at a center thereof; and a connection member located at an upper surface of the substrate and coupled to the first terminal of the external terminal, wherein the first terminal and the substrate are connected by means of the connection member, and the extension is connected to the substrate. Since positive and negative electrodes of the energy storage device are electrically connected to a substrate having a cell balancing function without a harness or any other member, it is possible to improve the economic feasibility and productivity of the energy storage device module.

Multi-cell battery packs can be made safer with certain features that mitigate the consequences of cell failure. Parameters of a cell are monitored to determine when the cell should be disconnected from the pack in case of a fault. The battery is reconfigured to continue operating in a safer mode. An over-charging prevention system reduces the maximum voltage that remaining battery pack can be charged to, so that the cells do not overcharge. Additional circuitry allows the disconnected cell to be periodically reconnected to the battery pack to determine if its conditions have sufficiently improved. The cells also include components for self-powering these cell functions while it is disconnected from the rest of the circuit.

A lithium-ion cell includes a ribbon-shaped electrode-separator assembly having an anode, a separator, and a cathode in a sequence anode/separator/cathode. The anode has a ribbon-shaped anode current collector having a first longitudinal edge, a second longitudinal edge, and two ends, wherein the anode current collector has a strip-shaped main region loaded with a layer of negative electrode material and a free edge strip extending along the first longitudinal edge that is not loaded with the electrode material. The cathode has a ribbon-shaped cathode current collector, wherein the cathode current collector has a strip-shaped main region loaded with a layer of positive electrode material and a free edge strip extending along the first longitudinal edge that is not loaded with the electrode material. The negative electrode material containing the at least one active material in a range of from 20 wt % to 90 wt %.