A lithium secondary battery includes a cathode formed from a cathode active material including a first cathode active material particle and a second cathode active material particle, an anode and a separator interposed between the cathode and the anode. The first cathode active material particle includes a lithium metal oxide including a continuous concentration gradient in at least one region between a central portion and a surface portion. The second cathode active material particle includes a lithium metal oxide including at least two metals except for lithium which have constant concentrations from a central portion to a surface, and the second cathode active material particle includes an excess amount of nickel among the metals except for lithium.

To provide a battery connecting body and a power supply device capable of maintaining a state where a cover portion covers a connecting member. A bus bar module includes a plurality of bus bars that each connects electrodes of adjacent ones of a plurality of batteries arranged such that the electrodes thereof are arranged on a straight line to electrically connect the plurality of batteries in series and a casing that houses the plurality of bus bars. The casing includes a plurality of bus bar housing portions that each house each of the bus bars and the cover portions that each cover an opening of each of the bus bar housing portions, and the cover portions are each retained by the bus bar.

A battery management device includes an SOC estimation unit, a storage unit, and a lithium deposition determination unit. The lithium deposition determination unit compares a differential coefficient of a battery voltage with respect to an SOC estimated by the SOC estimation unit and a differential coefficient of a battery voltage with respect to a reference SOC read from the storage unit, and determines that, if a difference is observed between the differential coefficients, lithium is deposited in a lithium ion secondary battery.

A power storage module is provided with: a pair of end plates for clamping a plurality of secondary cells arranged in parallel in one direction; first and second cover members fixed to one end plate of the pair of end plates, the first and second cover members being arranged facing the top surface of an enclosure, an electrode terminal being provided on the top surface; through-holes formed in the first and second cover members, the through-holes extending in the one direction; and engaging protrusions provided to first cell holders, the engaging protrusions protruding in the direction in which the first and second cover members are arranged, and being engaged with the first and second cover members, with the engaging protrusions passed through the through-holes.

The present disclosure relates to a separator for an electrochemical device with pores having predetermined diameter, permeation time, and tortuosity, to allow for smooth movement of lithium ions and a method for manufacturing the same, and smooth movement of lithium ions may be optimized by the separator for an electrochemical device.

The present application provides a top cover of a power battery, including a top cover plate, a first electrode unit and a second electrode unit, the top cover plate is provided with a deformable plate connecting hole and an insulation piece accommodating portion, the first electrode unit includes a deformable plate, a conductive plate and a first insulation piece, the deformable plate seals the deformable plate connecting hole, the conductive plate is located underneath the deformable plate, the first insulation piece includes a top cover plate connecting portion and a conductive plate connecting portion, the top cover plate connecting portion extends into the insulation piece accommodating portion and is fixed thereof, the conductive plate is insulated and fixed with the top cover plate through the conductive plate connecting portion. The present application further provides a power battery, including the top cover of the power battery.

Provided is a top cap assembly for a cylindrical type secondary battery, including a CID short-circuiting member, which interrupts an electric current when a high voltage is generated in the cylindrical type secondary battery, a safety vent connected to an upper part of the CID short-circuiting member and including a plurality of notches, which are broken when a voltage equal to or greater than an allowable voltage of the CID short-circuiting member is generated, to discharge gas from the cylindrical type secondary battery, a top cap connected to the safety vent and disposed on the uppermost end of an upper opening part of the cylindrical type secondary battery, a gasket surrounding and sealing an outer circumferential surface of the CID short-circuiting member, and a heat resistant member preventing heat transfer between the gasket and the safety vent.

Battery separators are presented having improved temperature ranges for battery shutdown. The battery separators include a first layer having a first shutdown temperature range, a second layer having a second shutdown temperature range, and a third layer having a third shutdown temperature range. The first shutdown temperature range and the second shutdown temperature range have a first overlap in temperature. The second shutdown temperature range and third shutdown temperature range have a second overlap in temperature. In some embodiments, the second layer is disposed between the first layer and the third layer to create a sandwiched structure.

A square secondary battery includes a generating element having an electrode; a battery can holding the generating element; a battery lid that seals an opening of the battery can; an external terminal arranged on the battery lid; and a current collector connecting the electrode of the generating element to the external terminal. The external terminal has a bus bar joint to which a bus bar is connected and a current collector joint to which the current collector is connected, the bus bar joint and the current collector joint being integrally juxtaposed on the battery lid. The current collector joint has a cylindrical insertion part to be inserted into a through hole in the battery lid and also has a sealing part arranged at an outer periphery of the insertion part, the sealing part pressing down a sealing member.

An electrolytic: solution for electrochemical devices includes: a salt consisting of a bifluoride anion and a cation; a compound containing boron; and an organic solvent.