Storage battery system and automobile

Abstract

A storage battery system includes a battery module including nonaqueous electrolyte secondary batteries. The storage battery system further includes a temperature sensor which measures a temperature of the battery module, a voltmeter which measures a voltage of each of the nonaqueous electrolyte secondary batteries and a charge control unit which controls a maximum end-of-charge voltage V 1 (V) of the nonaqueous electrolyte secondary batteries to fall within the range defined in formula (1) given below when the temperature of the battery module is not lower than 45° C. and is not higher than 90° C.: 0.85× V 0 ≦V 1 ≦0.96× V 0   (1)

1 . A storage battery system, comprising: 
 a battery module including nonaqueous electrolyte secondary batteries, each of the nonaqueous electrolyte secondary batteries comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, the negative electrode including a negative electrode layer and a current collector having the negative electrode layer mounted thereon, and the negative electrode layer contains lithium-titanium composite oxide particles;    a temperature sensor which measures a temperature of the battery module;    a voltmeter which measures a voltage of each of the nonaqueous electrolyte secondary batteries; and    a charge control unit which controls a maximum end-of-charge voltage V 1  (V) of the nonaqueous electrolyte secondary batteries to fall within the range defined in formula (1) given below when the temperature of the battery module is not lower than 45° C. and is not higher than 90° C.:      0.85 ×V   0   ≦V   1 ≦0.96 ×V   0    (1)    where V 0  denotes a maximum end-of-charge voltage (V) of the nonaqueous electrolyte secondary batteries when the battery module is charged fully at 25° C.    
     
     
         2 . The storage battery system according to  claim 1 , wherein the current collector of the negative electrode is formed of an aluminum foil or an aluminum alloy foil.  
     
     
         3 . The storage battery system according to  claim 1 , wherein each of the nonaqueous electrolyte secondary batteries has a charging rate falling within a range of 2 C to 120 C.  
     
     
         4 . The storage battery system according to  claim 1 , wherein the lithium-titanium composite oxide particles have an average particle diameter of no larger than 1 μm.  
     
     
         5 . The storage battery system according to  claim 1 , wherein the charge control unit controls the maximum end-of-charge voltage V 1  (V) of the nonaqueous electrolyte secondary batteries to fall within the range defined in the formula (1) when the temperature of the battery module is not lower than 45° C. and is not higher than 60° C.  
     
     
         6 . The storage battery system according to  claim 1 , wherein the lithium-titanium composite oxide particles contain lithium titanate particles having a spinel structure.  
     
     
         7 . The storage battery system according to  claim 1 , wherein the positive electrode contains a lithium-nickel-cobalt-manganese composite oxide represented by Li a Ni b Co c Mn d O 2  (where the molar ratio of a, b, c and d are: 0≦a≦1.1, b+c+d=1).  
     
     
         8 . The storage battery system according to  claim 1 , wherein the nonaqueous electrolyte contains at least one kind of a solvent selected from the group consisting of γ-butyrolactone, propylene carbonate and ethylene carbonate.  
     
     
         9 . The storage battery system according to  claim 1 , wherein the maximum end-of-charge voltage V 1  (V) of the nonaqueous electrolyte secondary batteries falls within the range defined in formula (2) given below when the temperature of the battery module is not lower than 45° C. and is not higher than 90° C.:  
         b  0 . 9   ×V   0   ≦V   1 ≦0.96 ×V   0    (2)  where V 0  denotes the maximum end-of-charge voltage (V) of the nonaqueous electrolyte secondary batteries when the battery module is charged fully at 25° C.    
     
     
         10 . The storage battery system according to  claim 1 , wherein the charge control unit controls a charging capacity of the battery module such that the maximum end-of-charge voltage V 1  (V) of the nonaqueous electrolyte secondary batteries falls within the range defined in the formula (1) when the temperature of the battery module is not lower than 45° C. and is not higher than 90° C.  
     
     
         11 . A storage battery system, comprising: 
 a battery module including nonaqueous electrolyte secondary batteries, each of the nonaqueous electrolyte secondary batteries comprising a negative electrode, a positive electrode and a nonaqueous electrolyte, the negative electrode including a negative electrode layer and a current collector having the negative electrode layer mounted thereon, and the negative electrode layer contains lithium-titanium composite oxide particles;    a dynamo which forms a regenerative power for charging the battery module;    a temperature sensor which measures a temperature of the battery module;    a voltmeter which measures a voltage of each of the nonaqueous electrolyte secondary batteries; and    a charge control unit which controls a maximum end-of-charge voltage V 1  (V) of the nonaqueous electrolyte secondary batteries to fall within the range defined in formula (1) given below when the temperature of the battery module is not lower than 45° C. and is not higher than 90° C.:      0.85 ×V   0   ≦V   1 23 0.96 ×V   0    (1)    where V 0  denotes a maximum end-of-charge voltage (V) of the nonaqueous electrolyte secondary batteries when the battery module is charged fully at 25° C.    
     
     
         12 . The storage battery system according to  claim 11 , wherein the current collector of the negative electrode is formed of an aluminum foil or an aluminum alloy foil.  
     
     
         13 . The storage battery system according to  claim 11 , wherein each of the nonaqueous electrolyte secondary batteries has a charging rate falling within a range of 2 C to 120 C.  
     
     
         14 . The storage battery system according to  claim 11 , wherein the lithium-titanium composite oxide particles have an average particle diameter of no larger than 1 μm.  
     
     
         15 . The storage battery system according to  claim 11 , wherein the charge control unit controls the maximum end-of-charge voltage V 1  (V) of the nonaqueous electrolyte secondary batteries to fall within the range defined in the formula (1) when the temperature of the battery module is not lower than 45° C. and is not higher than 60° C.  
     
     
         16 . The storage battery system according to  claim 11 , wherein the lithium-titanium composite oxide particles contain lithium titanate particles having a spinel structure.  
     
     
         17 . The storage battery system according to  claim 11 , wherein the positive electrode contains a lithium-nickel-cobalt-manganese composite oxide represented by Li a Ni b Co c Mn d O 2  (where the molar ratio of a, b, c and d are: 0≦a≦1.1, b+c+d=1).  
     
     
         18 . The storage battery system according to  claim 11 , wherein the maximum end-of-charge voltage V 1  (V) of the nonaqueous electrolyte secondary batteries falls within the range defined in formula (2) given below when the temperature of the battery module is not lower than 45° C. and is not higher than 90° C.:  
         0.9 ×V   0   ≦V   1 ≦0.96 ×V   0    (2)  where V 0  denotes the maximum end-of-charge voltage (V) of the nonaqueous electrolyte secondary batteries when the battery module is charged fully at 25° C.    
     
     
         19 . The storage battery system according to  claim 11 , wherein the charging control unit controls a charging capacity of the battery module such that the maximum end-of-charge voltage V 1  (V) of the nonaqueous electrolyte secondary batteries falls within the range defined in the formula (1) when the temperature of the battery module is not lower than 45° C. and is not higher than 90° C.  
     
     
         20 . An automobile comprising the storage battery system defined in  claim 11.