A secondary battery includes an outer package member, a battery device, and an insulating member. The outer package member has a flat and columnar shape and includes a first bottom part and a second bottom part opposed to each other. The battery device is contained inside the outer package member, and has a first through hole extending from the first bottom part toward the second bottom part. The insulating member is adhered in part to the battery device between the second bottom part and the battery device, and has a second through hole at a position overlapping with the first through hole.

An electrochemical apparatus formed by stacking and then winding a first separator, a negative electrode plate, a second separator, and a positive electrode plate. The negative electrode plate includes a negative electrode current collector, a first active material layer and a second active material layer. In a winding direction, a length of the first active material layer is greater than a length of the second active material layer. The first separator comprises a first substrate layer, a first coating layer and a second coating layer. The second separator comprises a second substrate layer, a third coating layer and a fourth coating layer. A bonding force between a first active material layer and a second coating layer is less than a bonding force between a second active material layer and a fourth coating layer.

Disclosed are a wound electrode assembly, and a method and manufacturing apparatus for manufacturing the wound electrode assembly. The wound electrode assembly includes an electrode sheet. The electrode sheet includes a winding ending section, the winding ending section is provided with a plurality of first tabs, the plurality of first tabs are laminated, and among the two adjacent first tabs, a width of the first tab close to a winding center of the wound electrode assembly is greater than a width of the first tab away from the winding center. Among the two adjacent first tabs, a width of the first tab close to the winding center is greater than a width of the first tab away from the winding center. After the winding ending section is wound, the amount of misalignment between the two adjacent first tabs is reduced.

According to an exemplary embodiment of the present invention, a roll press apparatus is provided. The roll press apparatus presses electrode sheets, each including a both-side coated portion where an electrode mixture is applied to both sides of a current collector and a one-side coated portion where the electrode mixture is applied to one side of a current collector, by passing the electrode sheet through a separated space between a pair of press rolls.

According to an exemplary embodiment of the present invention, a roll press apparatus is provided. The roll press apparatus presses electrode sheets, each including a both-side coated portion where an electrode mixture is applied to both sides of a current collector and a one-side coated portion where the electrode mixture is applied to one side of a current collector, by passing the electrode sheet through a separated space between a pair of press rolls.

The secondary battery includes an electrolytic solution, a positive electrode and a negative electrode, and the negative electrode includes a plurality of particulate negative electrode active materials, a first negative electrode binder, and a plurality of second negative electrode binders with an average particle size smaller than the plurality of particulate negative electrode active materials. The plurality of particulate negative electrode active materials have an average particle size of 5 μm or more and 30 μm or less. The first negative electrode binder includes one or both of a styrene butadiene rubber and a derivative thereof. The plurality of second negative electrode binders include one or both of a polyvinylidene fluoride and a derivative thereof, and the plurality of second negative electrode binders have an average particle size of 0.1 μm or more and 10 μm or less.

The secondary battery includes an electrolytic solution, a positive electrode and a negative electrode, and the negative electrode includes a plurality of particulate negative electrode active materials, a first negative electrode binder, and a plurality of second negative electrode binders with an average particle size smaller than the plurality of particulate negative electrode active materials. The plurality of particulate negative electrode active materials have an average particle size of 5 μm or more and 30 μm or less. The first negative electrode binder includes one or both of a styrene butadiene rubber and a derivative thereof. The plurality of second negative electrode binders include one or both of a polyvinylidene fluoride and a derivative thereof, and the plurality of second negative electrode binders have an average particle size of 0.1 μm or more and 10 μm or less.

A battery cell is configured such that a jelly-roll type electrode assembly is accommodated in a battery casing, and includes: the battery casing including upper, lower, and side surfaces, wherein the side surface of the battery casing includes an isolation wall providing a buffer space between the battery casing and the electrode assembly. The buffer space accommodates deformation of the electrode assembly when the electrode assembly is expanded, such that deformation of the side surface of the battery casing is prevented from occurring.

A battery cell is configured such that a jelly-roll type electrode assembly is accommodated in a battery casing, and includes: the battery casing including upper, lower, and side surfaces, wherein the side surface of the battery casing includes an isolation wall providing a buffer space between the battery casing and the electrode assembly. The buffer space accommodates deformation of the electrode assembly when the electrode assembly is expanded, such that deformation of the side surface of the battery casing is prevented from occurring.

The present application relates to an electrochemical device. Specifically, the present application provides a cell, wherein the cell is formed by winding or stacking a first electrode and a second electrode which are arranged at an interval, and a separator is disposed between the first electrode and the second electrode. Wherein the first electrode includes a first current collector, and the first current collector includes a coated region coated with a first active material and an uncoated region without the first active material; the uncoated region is at least partially provided with an insulating layer. The adhesion between the insulating layer and the first current collector is not less than about 0.5 N/m. The electrochemical device provided by the present application has improved safety performance.