How to judge the quality of NIMH battery?

A, The charging battery

1, the charge rate (C - rate)

C is the Capacity of the first letter, used to represent the size of the battery charge and discharge current values.

Rechargeable batteries, for example, the rated capacity is 1100mah, namely, said in a 1100mah sustainable for 1 hour, 1 C discharge time, such as 200 ma (0.2 C) discharge time sustainable 5 hours, charging can also be calculated at the controls.

2, termination voltage (Cut – off discharge voltage)

The point at which the battery discharge, the voltage drop to the battery should not continue to discharge the minimum operating voltage value.

According to the different cell types and different discharge conditions, the requirement of the capacity and life of battery is different also, so regulation of the termination of the battery discharge voltage is not the same.

Teach you how to use the multimeter to judge the stand or fall of rechargeable batteries

3, open circuit voltage (Open circuit voltage OCV)

Battery discharge, known as the open circuit voltage, has potential difference between the poles.

Open circuit voltage of battery, will be in accordance with the positive and negative battery electrolyte materials and, if the battery positive and negative materials are exactly the same, so no matter how big is the volume of the battery, the geometric structure, the open circuit voltage are the same.

4, the depth of discharge (Depth of discharge DOD)

In the process of the battery, the battery emits the percentage of the capacity of its rated capacity, called the depth of discharge.

Discharge the discretion of the depth and secondary battery charge life has a deep relationship, the deeper the depth of discharge when the secondary battery, the charging life is short, so when use should try to avoid deep discharge.

5, over discharge (Over discharge)

If batteries are in the process of discharge, more than the battery discharging termination voltage value, continue to discharge, he may be the cause of the battery internal pressure increases, positive and negative active material of reversible damage, reduce battery capacity of the.

6, charging, over charge

Battery charging, in after reaching full state, if continue to charge, may cause the battery internal pressure rise, battery case, such as deformation, midnight battery performance will be significantly reduced and damage.

Teach you how to use the multimeter to judge the stand or fall of rechargeable batteries

7, the energy density (Energy density)

Cells release by average per unit volume or the quality of electric energy.

General under the same volume, Lithium ion batteries energy density is 2.5 times that of the nickel cadmium battery is 1.8 times of NIMH batteries, so under the condition of the battery capacity is equal, lithium ion batteries will be smaller than the volume of nickel cadmium, nickel metal hydride batteries, lighter in weight.

8, self discharge (Self discharge)

Battery used or in any conditions, due to various reasons, causes the power loss phenomenon.

If in a month to calculate, lithium ion battery self discharge is about 1% - 2%, nickel metal hydride battery self discharge about 3% - 5%.

9, charging cycle life (Cycle life)

Rechargeable batteries used in repeated charge and discharge, the capacity of battery capacity gradually decreases back to the initial 60% to 80%.

10, memory effect (Memory effect)

In the battery charge and discharge process, can produce many small bubbles on the battery plate, a long period of time, the bubbles will reduce the area of the battery plate, also indirectly affect the capacity of the battery.

Second, how to use the multimeter to judge the stand or fall of rechargeable batteries

The following standard voltage of 4.2 V lithium ion batteries for example

If the full amount after the voltage is 4.2 V, can also, if you use the battery reached 0.7 times of new battery time above, means that the battery is good, if the full amount after the voltage is higher than 4.2 V, shows that there is something wrong with the charger, (pay attention to the voltmeter must be accurate).Please see below.

1, the nominal voltage of 3.7 V lithium ion batteries (3.6 V), charge cut-off voltage of 4.2 V, 4.1 V, according to the label of batteries have different design).Lithium ion batteries (specification is: lithium ion secondary battery)

2, requirements for lithium ion batteries (GB/T182872000 specification) : first of all, constant current charging, namely must be current, and battery voltage with the charging process gradually increases, when the battery voltage of 4.2 V, 4.1 V), constant voltage charging, instead of constant current charging for the voltage must be current depending on the degree of saturation batteries, as the charging process continue to gradually reduce, when reduced to 0.01 C, think charging termination.(C is a sign of nominal capacity battery control current methods, such as the battery capacity is 1000mAh, 1 C is the charging current 1000mA, attention is MA not MAH, 10mA is 0.01 C.)Normative representation is 0.01 C5A, of course, I'm here to simplify.

Teach you how to use the multimeter to judge the stand or fall of rechargeable batteries

3, why do you consider 0.01 C for the charging end: this is stipulated in the national standard GB/T18287-2000, are also discussed. Used widely to 20 ma to end, posts and telecommunications industry standard YD/T998-1999 in the same way, that no matter how much battery capacity, to stop the current 20 ma. National standard of 0.01 C help charging more full, through identification on the part of the manufacturer. In addition, national standard rules on the charging time not more than eight hours, that is to say even if haven't reached 0.01 C, 8 hours, also think charging end.(quality no problem of the battery, should be within 8 hours at 0.01 C, battery quality is bad, also meaningless wait)

4, since the battery with protection board, whether we can rest assured: no, because of the protective plate as parameter is 4.35 V (this is good, and poor in 4.4 to 4.5 V), protective plate is one thousand, if every time the overcharge, the battery will soon decay.

5, how much of a charging current is appropriate: theoretically, the smaller the battery is good. But you can't for a piece of battery such as 3 days. National standard of low charge ratio is 0.2 C (charging arbitration system), still above the 1000mah capacity of the battery, for example, is 200ma, so we can estimate the battery only can charge more than five hours. Capacity (MAH = current MA x time h) national technical supervision departments Lithium electricity charging capacity, is a high rate of 1 C, low discharge of 0.2 C, with time to calculate the capacity value, test times, 5 times capacity to one end of the test.(that is, there are 5 times, if the first test is qualified, the back of the four do not) allowed once precycling before detection, with 1 C is constant current charging 4.2 V namely stop, without following the process of constant pressure to 0.01 C, no 14 hours more.

Teach you how to use the multimeter to judge the stand or fall of rechargeable batteries

6, lithium ion battery can bear how much charging current: when the factory test can be very high, but the elevation specified as 1 c ratio, also more than the battery, for instance, can be more than an hour. Such a large charging current, battery can bear? For the current lithium ion batteries, it is something. There is no national standard for the charger, which is performed by ministry of posts and telecommunications industry standard YD/T9981999/2, which sets the current of the charger shall not be greater than 1 c.

7, what is the life: simple refers to the battery after N times, after 1 c, 1 c discharge capacity decreased to 70%, when N is life. It’s not to say that you can also use 300 times, 301 times cannot be used. National standard specified life should not be less than 300times. We usually use the condition of no detection so harsh, longer service life.

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