Firstly introduce a few simple formula, the basic electricity hope to make no electronic background readers to a few physical phenomena.
Voltage (V) = current (I) x resistance (R),
Charge (Q) = current (I) x time (T),
Power (P = V x I =
Energy (W) = P * T = Q x V
Any object has impedance, plus a potential difference in both impedance will produce charge through the impedance, the impedance is unit of time (a) through the charge quantity smaller, impedance is unit of time through the charge quantity. If the potentials are unit time increases the flow volume of charge will be reduced, while magnetic unit time through the charge quantity is less. The potential difference voltage (V), called for volts (V) unit, unit of time through the charge quantity amount called current (I), unit for (A), impedance ampere resistance (R), called in ohms (.). The current (I) that flows through the unit of time, the number of charges in the flow resistance in T seconds altogether has the number of charges by T, I used to describe how the charge quantity of nouns for charge (Q), commonly known as the power, the unit is called the coulomb (Q). Resistance of power consumption (P) as I * V, unit for watt (W), representing the power the power consumption. , the energy consumption (W) for P * T, unit for the joule (J), the longer the time the same energy consumption, and the energy consumption of power consumption is bigger also.
Example: a tree in the dry batteries 1.5 V, consumption of 0.5 bulb, power consumption for triple-a current for 4.5 W, 10 seconds altogether through the coulomb’s charge, 30 45 joule energy consumption. Nickel cadmium battery material classification of battery has a lot of kinds, in chemical battery charging in just throw a battery, the battery can be called again use rechargeable batteries repeatedly called secondary battery, the battery is nickel cadmium and alkaline battery in the secondary batteries belong to one. Nickel cadmium battery anode materials are used in QingYangHuaNie oxygen, cathode using cadmium compounds active substances, electrolyte is the use of potassium hydroxide alkaline solution, etc. As for nickel cadmium battery, will be produced in the above, in QingYangHuaNie anode and cathode metal cadmium, thus it has formed in at the potentials. Will nickel cadmium battery anode and cathode ends when discharge, Yin external load extreme charged by external load flow of electrons, therefore to provide energy for anode external load consumption.

Second, excessive charging
In the process of charging the battery voltage increases with the increased power storage battery storage rise gradually, when the electrode material of saturation power battery, if cannot continue to charge, electrolyte, and will produce in the electrolysis anode and cathode generate hydrogen in oxygen, so will the internal cause in sealed battery, will rise to internal pressure inside the cell damage structure. Like this kind of phenomenon called excessive charging.
In order to avoid excessive rechargeable batteries, usually by the damage of the cathode production capacity will be better than the anode, large capacity, such as excessive charge anode can produce oxygen saturation and first, and the cathode is not saturated and won’t produce hydrogen and oxygen to produce spread to the anode and cathode after charging produced metal cadmium absorbed oxygen react, and the reaction rate and metal cadmium speed balance, so can effectively avoid the battery pressure. But if the charging current (use) will be quick charge the battery loses his balance, the pressure inside the battery will open valve, hydrogen and oxygen to battery leakage will reduce external pressure relief valve closed until just sealed battery again. But the gas leakage has made chemical material, reducing internal cause of battery life.