Charging method and charging device

Abstract

A charging method of a secondary battery having plural cells includes: connecting the plural cells in series and conducting constant current charging by a first power source; measuring voltages of the plural cells; and connecting the plural cells in parallel and conducting constant voltage charging by a second power source, a voltage of which is lower than a voltage of the first power source, in the case where a measured voltage difference among the plural cells is smaller than a specified value.

What is claimed is: 
     
         1 . A charging method for charging plural cells, comprising:
 connecting the plural cells in series and conducting constant current charging by a first power source;   measuring voltages of the plural cells; and   connecting the plural cells in parallel and conducting constant voltage charging by a second power source, a voltage of which is lower than a voltage of the first power source, in a case where a measured voltage difference among the plural cells is smaller than a specified value.   
     
     
         2 . The charging method according to  claim 1 , wherein the constant current charging is stopped when at least one of the plural cells or predetermined number of the cells reach a specified voltage. 
     
     
         3 . The charging method according to  claim 1 , wherein, in the charging method, a charging device that includes: a conductive pin that is connected to a terminal of each of the plural cells and supplies electric power to each of the plural cells; and a voltage measuring pin that is connected to the terminal and measures the voltage of each of the plural cells and, in which the voltage measuring pin comes in contact with the terminal ahead of the conductive pin, is used,
 wherein, in conducting the constant current charging or in conducting the constant voltage charging, when the plural cells are connected to the first power source or the second power source, the voltage measuring pin is brought into contact with the terminal so as to measure the voltage of each of the plural cells, and   wherein, in a case where the measured voltage does not fall within a specified range, contact between each of the plural cells and the conductive pin is prohibited.   
     
     
         4 . The charging method according to  claim 1 , wherein:
 in the charging method, a charging device that includes: a conductive pin that is connected to a terminal of each of the plural cells and supplies electric power to each of the plural cells; and a voltage measuring pin that is connected to the terminal and measures the voltage of each of the plural cells and, in which the voltage measuring pin is detached from the terminal ahead of the conductive pin when the voltage measuring pin and the conductive pin are displaced in a direction along a terminal surface on which the terminal is arranged, is used;   in conducting the constant current charging or in conducting the constant voltage charging, the voltages of the plural cells are measured; and   in a case where the measured voltage does not fall within a specified range, connection between the plural cells and the first power source or the second power source is cancelled.   
     
     
         5 . The charging method according to  claim 1 , wherein in a case where the voltage difference among the plural cells after the constant current charging is smaller than the specified value, the plural cells are connected in parallel and are subjected to the constant voltage charging by the second power source. 
     
     
         6 . The charging method according to  claim 5 , wherein in a case where it is determined that the voltage difference among the plural cells after the constant current charging is at least equal to the specified value, connection of one or some of the cells is cancelled such that the voltage difference among the plural cells becomes smaller than the specified value. 
     
     
         7 . A charging device for charging plural cells, comprising:
 a first power source;   a second power source, a voltage of which is lower than that of the first power source; and   a voltage measuring section for measuring voltages of the plural cells,   wherein the plural cells are connected in series and are subjected to constant current charging by the first power source, and   wherein the plural cells are connected in parallel and are subjected to constant voltage charging by the second power source in a case where a voltage difference among the plural cells after the constant current charging is smaller than a specified value.   
     
     
         8 . The charging device according to  claim 7 , wherein the constant current charging is stopped when at least one of the plural cells or predetermined number of the cells reach a specified voltage. 
     
     
         9 . A charging device comprising:
 a positive electrode terminal conductive pin that is connected to a positive electrode terminal of a cell and supplies electric power to the cell;   a positive electrode terminal voltage measuring pin that is connected to the positive electrode terminal of the cell and measures a voltage of the cell;   a negative electrode terminal conductive pin that is connected to a negative electrode terminal of the cell, is paired with the positive electrode terminal conductive pin, and supplies the electric power to the cell; and   a negative electrode terminal voltage measuring pin that is connected to the negative electrode terminal of the cell, is paired with the positive electrode terminal voltage measuring pin, and measures the voltage of the cell,   wherein a tip position of the positive electrode terminal voltage measuring pin is closer to the positive electrode terminal than that of the positive electrode terminal conductive pin, and a tip position of negative electrode terminal voltage measuring pin is closer to the negative electrode terminal than that of the negative electrode terminal conductive pin, and   wherein tips of the positive electrode terminal voltage measuring pin and the negative electrode terminal voltage measuring pin are retractable when respectively abutting against the positive electrode terminal and the negative electrode terminal.   
     
     
         10 . The charging device according to  claim 9 , wherein, on a terminal surface of the cell, on which the positive electrode terminal and the negative electrode terminal are arranged, the positive electrode terminal conductive pin is positioned in a vicinity of a center of the positive electrode terminal, the negative electrode terminal conductive pin is positioned in a vicinity of a center of the negative electrode terminal, the positive electrode terminal voltage measuring pin is positioned on an outer side of the positive electrode terminal conductive pin when seen from a middle point between the positive electrode terminal conductive pin and the negative electrode terminal conductive pin, and the negative electrode terminal voltage measuring pin is positioned on an outer side of the negative electrode terminal conductive pin when seen from the middle point.