Nonaqueous electrolyte battery and battery pack

Abstract

According to one embodiment, a nonaqueous electrolyte battery includes a positive electrode, a negative electrode, and a nonaqueous electrolyte. The positive electrode includes at least one oxide selected from the group consisting of a first oxide having a spinel structure and represented by Li x Ni 0.5 Mn 1.5 O 4 , a second metal phosphate having an olivine structure and represented by Li x Mn 1-w Fe w PO 4 , and a third oxide having a layered structure and represented by Li x Ni y Mn z Co 1-y-z O 2 . The nonaqueous electrolyte includes a first solvent. The first solvent includes at least one compound selected from the group consisting of trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, and fluorinated phosphate ester.

What is claimed is: 
     
         1 . A nonaqueous electrolyte battery comprising:
 a positive electrode comprising at least one oxide selected from the group consisting of a first oxide having a spinel structure and represented by Li x Ni 0.5 Mn 1.5 O 4  (0<x≦1.1), a second metal phosphate having an olivine structure and represented by Li x Mn 1-w Fe w PO 4  (0<x≦1.1, 0≦w≦0.5), and a third oxide having a layered structure and represented by Li x Ni y Mn z Co 1-y-z O 2  (0<x≦1.1, 0.3≦y<1,0≦z≦0.5);   a negative electrode comprising a titanium-containing oxide; and   a nonaqueous electrolyte comprising a nonaqueous solvent and an electrolyte dissolved in the nonaqueous solvent, wherein the nonaqueous solvent comprises a first solvent comprising at least one compound selected from the group consisting of trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate and fluorinated phosphate ester.   
     
     
         2 . The nonaqueous electrolyte battery according to  claim 1 , wherein the first solvent comprises the fluorinated phosphate ester. 
     
     
         3 . The nonaqueous electrolyte battery according to  claim 1 , wherein the positive electrode comprises the third oxide. 
     
     
         4 . The nonaqueous electrolyte battery according to  claim 1 , wherein the fluorinated phosphate ester comprise at least one selected from the group consisting of trifluoromethyl phosphate, trifluoroethyl phosphate, trifluoropropyl phosphate, and trifluorobutyl phosphate. 
     
     
         5 . The nonaqueous electrolyte battery according to  claim 1 , wherein the electrolyte comprises LiPF 6 . 
     
     
         6 . The nonaqueous electrolyte battery according to  claim 1 , wherein the nonaqueous solvent further comprises a second solvent comprising at least one selected from the group consisting of propylene carbonate, ethylene carbonate, butylene carbonate, diethyl carbonate, ethylmethyl sulfone, and ethylisopropyl sulfone, and a content of the first solvent in the nonaqueous solvent is 30 to 90% by volume. 
     
     
         7 . The nonaqueous electrolyte battery according to  claim 1 , wherein the titanium-containing oxide comprises at least one selected from the group consisting of a lithium titanium oxide, a titanium oxide, and a niobium titanium composite oxide. 
     
     
         8 . A battery pack comprising the nonaqueous electrolyte battery according to  claim 1 . 
     
     
         9 . A nonaqueous electrolyte battery comprising:
 a positive electrode comprising at least one of a first oxide having a spinel structure and represented by Li x Ni 0.5 Mn 1.5 O 4  (0<x≦1.1), and a second metal phosphate having an olivine structure and represented by Li x Mn 1-w Fe w PO 4  (0<x≦1.1, 0≦w≦0.5);   a negative electrode comprising a titanium-containing oxide; and   a nonaqueous electrolyte comprising a nonaqueous solvent and LiPF 6  dissolved in the nonaqueous solvent, wherein the nonaqueous solvent comprises a first solvent comprising at least one compound selected from the group consisting of trimethyl phosphate, triethyl phosphate, tripropyl phosphate, and tributyl phosphate, and/or fluorinated phosphate esters of the at least one compound.   
     
     
         10 . The nonaqueous electrolyte battery according to  claim 9 , wherein the nonaqueous solvent further comprises a second solvent comprising at least one selected from the group consisting of propylene carbonate, ethylene carbonate, butylene carbonate, ethylmethyl sulfone, and ethylisopropyl sulfone, and a content of the first solvent in the nonaqueous solvent is 30 to 90% by volume. 
     
     
         11 . The nonaqueous electrolyte battery according to  claim 9 , wherein the nonaqueous solvent further comprises a second solvent comprising at least one selected from the group consisting of propylene carbonate, ethylene carbonate, butylene carbonate, diethyl carbonate, ethylmethyl sulfone, and ethylisopropyl sulfone, and a content of the first solvent in the nonaqueous solvent is 30 to 90% by volume. 
     
     
         12 . The nonaqueous electrolyte battery according to  claim 9 , wherein the titanium-containing oxide comprises at least one selected from the group consisting of a lithium titanium oxide, a titanium oxide, and a niobium titanium composite oxide. 
     
     
         13 . A battery pack comprising the nonaqueous electrolyte battery according to  claim 9 .