Sony Corporation

Mamoru Hosoya

Yuzuru Fukushima

Kimio Takahashi

Junji Kuyama

Hideki Sakai

Masami Miyake

Tsuyoshi Okawa

Takahiro Endo

Shuji Goto

A non-aqueous electrolyte cell is provided having improved cell characteristics and which maintains a cell shape encapsulated in a laminate film even when overdischarged to a cell voltage of 0 V. The cell includes an anode, an electrolyte, and a cathode containing a compound having the formula LiFeMPO, wherein 0.05&#x2266;x&#x2266;1.2 and 0&#x2266;y&#x2266;0.8, and wherein M is at least one element selected from the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B and Nb. Exposed portions of an anode current collector and a cathode current collector prevent internal shorting of the cell.

Non-aqueous electrolyte cell and solid electrolyte cell

A cell in which liquid leakage or destruction may be prevented as the apparent energy density per unit volume of the cell is maintained. The cell uses, as a cathode active material, a compound of an olivinic crystal structure having the formula LiFeMPO, where M is at least one selected from the group of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B and Nb, with 0.05&#x2266;x&#x2266;1.2 and 0&#x2266;y&#x2266;0.8. By adjusting the amount of the electrolyte solution, the amount of the void in the container is set so as to be not less than 0.14 cc and not more than 0.3 cc per 1 Ah of the cell capacity.

Non-aqueous electrolyte secondary cell with a lithium metal phosphate cathode

A LiFePOcarbon composite material is to be synthesized in a single phase satisfactorily to prevent the deterioration of the performance of the cathode active material from occurring and achieve superior cell characteristics. In preparing a cathode active material, starting materials for synthesis of a compound represented by the general formula LiFePO, where 0&#x3c;x&#x2266;1, are mixed, milled and a carbon material is added to the resulting mass at an optional time point in the course of mixing, milling and sintering. LiPO, Fe(PO)or its hydrates Fe(PO).nHO, where n denotes the number of hydrates, are used as the starting materials for synthesis of LiFePO. The temperature of a product from said sintering is set to 305&#xb0; C. or less when said product from said sintering is exposed to atmosphere.

Method for the preparation of cathode active material and method for the preparation of non-aqueous electrolyte

A non-aqueous electrolyte cell having high discharge capacity, an improved capacity upkeep ratio and optimum cyclic characteristics. The non-aqueous electrolyte cell has a cell device including a strip-shaped cathode material and a strip-shaped anode material, layered and together via a separator and coiled a plural number of times, a non-aqueous electrolyte solution, and a cell can for accommodating cell device and the non-aqueous electrolyte solution. The cathode employs a cathode active material containing a compound of the olivinic structure represented by the general formula LiFeMPO, where M is at least one selected from the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B and Nb, with 0.05&#x2266;x&#x2266;1.2 and 0&#x2266;y&#x2266;0.8, with the compound being used either singly or in combination with other materials. The ratio of an inner diameter d to an outer diameter D of cell device is selected so that 0.05&#x3c;d/D&#x3c;0.5.

Non-aqueous electrolyte cell

A method for producing a cathode active material having superior cell characteristics through single-phase synthesis of a composite material composed of a compound represented by the general formula Li Fe M PO and a carbon material positively and a method for producing a non-aqueous electrolyte cell employing the so produced cathode active material. To this end, the cathode active material is prepared by a step of mixing the starting materials for synthesis of the compound represented by the general formula Li Fe M PO , a step of milling a mixture obtained by the mixing step, a step of compressing the mixture obtained by the mixing step to a preset density and a step of sintering the mixture obtained by the compressing step. A carbon material is added in any one of the above steps prior to the sintering step. The density of the mixture in the compressing step is set to not less than 1.71 g/cm and not larger than 2.45 g/cm .

Method for producing cathode active material and method for producing non-aqueous electrolyte cell

A LiFePO carbon composite material is to be synthesized in a single phase satisfactorily to achieve superior cell characteristics. In preparing a cathode active material, a starting material for synthesis of a compound represented by the general formula Li FePO , where 0<x&lE;1, is mixed, milled and sintered and a carbon material is added to the resulting mass at an optional time point in the course of mixing, milling and sintering. Li PO , Fe (PO ) or its hydrates Fe (PO ) H O, where n denotes the number of hydrates, are used as the starting material for synthesis of Li FePO . The particle size distribution of particles of the starting material for synthesis following the milling with the particle size not less than 3 &mgr;m is set to 2.2% or less in terms of the volumetric integration frequency.

A LiFePO carbon composite material is to be synthesized in a single phase satisfactorily to achieve superior cell characteristics. In preparing a cathode active material, starting materials for synthesis of a compound represented by the general formula Li FePO , where 0<x&lE;1, are mixed, milled and a carbon material is added to the resulting mass at an optional time point in the course of mixing, milling and sintering. Li PO , Fe (PO ) or its hydrates Fe (PO ) &middot;nH O, where n denotes the number of hydrates, are used as the starting materials for synthesis of Li FePO . The the temperature of a product from said sintering is set to 305&deg; C. or less when said product from said sintering is exposed to atmosphere. The oxygen concentration in a sintering atmosphere is set to 1012 ppm in volume or less at the time point of sintering.

A solid electrolyte cell in which cell characteristics are not deteriorated even on overdischarge to the cell voltage of 0V, such that the shape of the cell encapsulated in the laminate film is maintained. The cell includes a cathode containing a compound represented by the general formula Li Fe M PO where 0.05&lE;x&lE;1.2, 0&lE;y&lE;0.8, and M is at least one selected from the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B and Nb, an anode and a solid electrolyte. An electrode unit comprised of the cathode and the anode layered together with interposition of the solid electrolyte is encapsulated with a laminate film

Solid electrolyte cell

A non-aqueous electrolyte secondary cell containing a compound of an olivinic structure as a cathode active material is to be improved in load characteristics and cell capacity. To this end, there is provided a non-aqueous electrolyte secondary cell including a cathode having a layer of a cathode active material containing a compound represented by the general formula Li Fe M PO , where M is at least one selected from the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B and Nb, with 0.05&lE;x&lE;1.2 and 0&lE;y&lE;0.8, an anode having a layer of a cathode active material containing the anode active material and a non-aqueous electrolyte, wherein the layer of the cathode active material has a film thickness in a range from 25 to 110 &mgr;m. If a layer of a cathode active material is provided on each surface of a cathode current collector, the sum of the film thicknesses of the layers of the cathode active material ranges between 50 and 220 &mgr;m. The non-aqueous electrolyte may be a liquid-based electrolyte or a polymer electrolyte.

Growing community of inventors

Kanagawa, Japan

Mamoru Hosoya