This disclosure relates generally to battery cells, and more particularly, electrolyte additives for use in lithium ion battery cells.

A main object of the present disclosure is to provide an all solid state battery wherein interface resistance between a current collector and an active material layer is low. In the present disclosure, the above object is achieved by providing an all solid state battery comprising: an electrode including a current collector, an electron conductive layer, and an active material layer, in this order, and a solid electrolyte layer formed on the active material layer side of the electrode, and the electron conductive layer is an agglutinate of metal particles or a metal foil, and electron conductivity of the electron conductive layer is 1×10.sup.3 S/cm or more at 25° C.

A hot-pressing tool mounted on a press and operable under a controlled atmosphere, a method for implementing such a hot-pressing tool, and a facility for manufacturing objects that includes such a hot-pressing tool. The tool includes a first tool portion having a first fastening device to fasten onto a first platen, a second tool portion having a second fastening device to fasten onto a second platen. The first fastening device and the second fastening device are mobile with respect to one another to define a pressing chamber having an inner volume which is heated via a heating device. The first fastening device and the second fastening device each respectively have a pressing member to exert a pressing force on opposite faces of an object to be pressed in the pressing chamber. The heating device is to heat via optical radiation that is concentrated on the object via a concentration device.

This method achieves lithium cobalt pyrophosphate in which the generation of different phases is suppressed. A powder of a lithium compound, a cobalt compound and a phosphorus compound in amounts based on the composition of lithium cobalt pyrophosphate is mixed while adding water at a prescribed temperature (T1), for example, room temperature, and the substance obtained thereby is further mixed at a higher temperature (T2), for example, 40° C.-60° C. In this way, a precursor of lithium cobalt pyrophosphate is formed that has excellent uniformity of distribution of the lithium component, the cobalt component and the phosphorus component. By firing such a precursor, a lithium cobalt pyrophosphate is obtained in which the generation of different phases is suppressed.

This method achieves lithium cobalt pyrophosphate in which the generation of different phases is suppressed. A powder of a lithium compound, a cobalt compound and a phosphorus compound in amounts based on the composition of lithium cobalt pyrophosphate is mixed while adding water at a prescribed temperature (T1), for example, room temperature, and the substance obtained thereby is further mixed at a higher temperature (T2), for example, 40° C.-60° C. In this way, a precursor of lithium cobalt pyrophosphate is formed that has excellent uniformity of distribution of the lithium component, the cobalt component and the phosphorus component. By firing such a precursor, a lithium cobalt pyrophosphate is obtained in which the generation of different phases is suppressed.

The purpose of the present invention is to provide a lithium secondary battery having a high energy density and an excellent cycle characteristic. The present invention relates to a lithium secondary battery equipped with a positive electrode, a negative electrode not having a negative electrode active material, a separator placed therebetween, and a fibrous or porous buffering function layer formed on the surface of the separator facing the negative electrode and having ionic conductivity. The positive electrode contains a positive electrode active material and a lithium-containing compound which causes an oxidation reaction and does not substantially cause a reduction reaction in a charge/discharge potential range of the positive electrode active material. In a particle size distribution by the laser diffraction method, the lithium-containing compound has a particle size D.sub.50 (S), which corresponds to a cumulative degree at 50%, of 1.0 μm or more and 20 μm or less and a particle size D.sub.95 (S), which corresponds to a cumulative degree at 95%, of 1.0 μm or more and 30 μm or less.

A unit cell including a thermochromic polymer and a defect detection method using the same are disclosed. Preferably, the unit cell includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, wherein the separator includes a thermochromic polymer configured such that the color of the thermochromic polymer changes depending on temperature, whereby the unit cell is easily checked to indicate a short circuit, as well as damage to or defects of the separator.

A secondary battery includes an outer package member, an electrode terminal, and a battery device. 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 electrode terminal is supported by the first bottom part and is insulated from the first bottom part. The battery device is contained inside the outer package member and includes a first electrode and a second electrode. The first bottom part has a recess around the electrode terminal.

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.

The present invention provides a battery module, which includes: a plurality of battery cells which include electrode tabs, respectively; and one or more bus bars connected to the electrode tabs for electrically connecting the plurality of battery cells with each other, wherein each of the one or more bus bars includes a plate having one or more openings formed therein, and a plurality of adjacent electrode tabs among the electrode tabs are inserted into any one of the one or more openings of the plate to be electrically connected with each other.