The present invention provides: a composition with which the surface of a stainless steel is sufficiently roughened in an efficient manner with few steps; a method for roughening a stainless steel; and the like. The above are achieved by means of a composition for roughening the surface of a stainless steel, said composition containing from 0.1% by mass to 25% by mass of one or more substances that are selected from the group consisting of persulfuric acid and persulfuric acid salts based on the total amount of the composition, and from 1% by mass to 30% by mass of halide ions based on the total amount of the composition.

The steel foil for a current collector according to the present disclosure includes a ferritic stainless steel foil. In an X-ray diffraction profile with CoK rays of the ferritic stainless steel foil according to the present disclosure, the half width Fw of the peak for the {110} plane is 0.40 to 0.52.

An apparatus for manufacturing an electrode according to an embodiment of the present disclosure includes: a supply portion supplying an electrode plate to which an electrode active material is applied; at least one thickness measuring portion measuring a thickness of the electrode plate; and at least one thickness reinforcing portion adding at least one reinforcing material to the electrode plate. An electrode assembly according to an embodiment of the present disclosure includes: a positive electrode plate to which a positive active material is applied, a negative electrode plate to which a negative active material is applied, and at least one of the positive electrode plate and the negative electrode plate includes at least one reinforcing material in at least a partial region thereof.

A nonaqueous electrolyte secondary battery including: an electrode group including a first electrode having a first current collector, a second electrode having a second current collector, and a separator interposed therebetween; a nonaqueous electrolyte; all housed in a battery case. The first electrode and the second electrode are wound with the separator interposed therebetween, with an outermost layer of the first electrode disposed further outside than an outermost layer of the second electrode. The winding-finish end of the first electrode is an end of an excess portion which is wound around an outer surface of the first electrode on an inner layer side, without the second electrode interposed therebetween. The circumferential length L1 of the excess portion is 90% or more of the circumferential length L of the first electrode of the outermost layer. The excess portion has a functional layer disposed on a surface of the first current collector.

An embodiment of this application provides a current collector and a preparation apparatus thereof, an electrode plate, a battery, and an electrical device. The current collector includes a main region and a tab region disposed along a first direction. The main region includes a first metal. The first metal includes at least one of Ni, Fe, or stainless steel. The tab region includes a second metal. The second metal includes at least one of Cu, Ag, Au, or W, and optionally includes Cu.

An object is to provide a nickel-plated steel sheet where both the adhesiveness of a plated layer to a substrate and the adhesiveness of the plated layer to another member are ensured and that has a reduced total thickness including a roughened layer. This is solved by means of a nickel-plated steel sheet having a substrate made of a steel sheet, a roughened nickel layer provided on the substrate, and an iron-nickel alloy layer provided between the substrate and the roughened nickel layer.

To provide a power storage device whose charge and discharge characteristics are unlikely to be degraded by heat treatment. To provide a power storage device that is highly safe against heat treatment. The power storage device includes a positive electrode, a negative electrode, a separator, an electrolytic solution, and an exterior body. The separator is located between the positive electrode and the negative electrode. The separator contains polyphenylene sulfide or solvent-spun regenerated cellulosic fiber. The electrolytic solution contains a solute and two or more kinds of solvents. The solute contains LiBETA. One of the solvents is propylene carbonate.

An electrochemical device including a bipolar current collector. The bipolar current collector is hermetically connected to an outer package. Cavities independent of each other are formed on two opposite sides of the bipolar current collector. Each cavity contains an electrode assembly and an electrolytic solution. An electrode active material is disposed on at least one surface of the bipolar current collector. Adjacent electrode assemblies are connected in series. The electrochemical device according to this application not only improves the safety of the electrochemical device, but the electrode active material on the surface of the bipolar current collector also participates in a reaction process in the electrochemical device, so that the electrochemical device achieves both a high-voltage output and a relatively high energy density.

A method for manufacturing an anode electrode includes supplying an anode current collector; coating a first portion of the anode current collector with a precursor coating; not coating a second portion of the anode current collector with the precursor coating; treating the anode current collector with plasma to at least one of decrease lithium wettability of the first portion and to increase lithium wettability of the second portion; and coating the anode current collector with lithium metal to form an anode active material layer.

Provided herein is a modified current collector for a secondary battery, comprising a substrate and a conductive layer applied on one side or both sides of the substrate, wherein the conductive layer comprises a conductive material and binder material, wherein the binder material comprises a copolymer. Also provided herein is an electrode for a secondary battery, comprising the modified current collector and an electrode layer, wherein the electrode layer is located on the surface of the conductive layer(s). Within an electrode comprising the modified current collector disclosed herein, the presence of the conductive layer inhibits corrosion of the substrate and reduces interfacial resistance between the electrode layer and the substrate. Consequently, batteries comprising such an electrode exhibit exceptional electrochemical performance.