Must see the proper use of the battery

Have to look at the correct way to use the battery

1, cognitive memory effect (mainly talking about nickel-cadmium and nickel-metal hydride batteries, not interested can be omitted directly to see No. 2)

The battery memory effect refers to the reversible failure of the battery, that is, the performance of the battery that can be restored after the battery fails. The memory effect refers to the automatic maintenance of this specific tendency after the battery has undergone a specific working cycle for a long time. This was originally defined in nickel-cadmium batteries., Nickel-cadmium bag batteries have no memory effect, sintered batteries have memory effects, and current nickel-metal hydrogen (commonly known as nickel-metal hydrogen) batteries are not bound by this memory effect definition.

Because of the improvement of the modern nickel-cadmium battery process, the above memory effect has been greatly reduced, and another phenomenon has replaced this definition, which is the "crystallization" of nickel-based batteries. Usually, nickel-cadmium batteries are affected by these two effects. The combination of effects, the nickel-metal hydride battery is only affected by the "grid" memory effect, and the effect is smaller than that of nickel-cadmium batteries.

In practical application, the method of eliminating memory effects has strict specifications and an operation process, and improper operation can backfire.

For nickel-cadmium batteries, the normal maintenance is regular deep discharge: an average of one month (or 30 cycles) for a deep discharge (discharge to 1.0V / per section, foreigners called exercise), the usual use is to use light batteries Or use shutdown to ease the formation of memory effects, but this is not exercise, because the instrument (such as mobile phone) will not use 1.0V / every section to shut down, you must have a special equipment or line to complete the work Fortunately, many NiMH battery chargers have this feature.

For the nickel-cadmium battery that has not been carried out for a long time, because of the accumulation of memory effects, it will not be possible to restore the capacity with exercise. At this time, a deeper discharge is required (foreigners call redefinition). This is a process in which the battery is discharged to 0.4 V per section for a long time with a very small current and requires professional equipment.

For nickel-metal hydride batteries, the frequency of exercise can effectively relieve the memory effect every three months, because the cycle life of nickel-metal hydride batteries is much lower than that of nickel-cadmium batteries, and the method of redefinition is almost impossible to use.

Recommendation 1: Before each charge, discharge is unnecessary and harmful because the battery's useful life is needlessly reduced.

Recommendation 2: It is not advisable to discharge a battery with a positive or negative electrode connected to a resistor. The current can not be controlled, it is easy to overload to 0V, and even causes the battery polarity of the series battery to reverse.

2, Does the battery need to be activated?

The answer is that the battery needs to be activated, but this is not what the user needs to do. I visited the lithium ion battery manufacturing plant. The lithium ion battery has to go through the following process before it goes out of the factory:

The lithium-ion battery shell injects the electrolyte -- the seal -- into a constant pressure charge, and then discharges, so that several cycles are carried out, so that the electrode fully infiltrates the electrolyte, fully activates, and reaches the required capacity. This is the activation process -- the cell size, which is the battery capacity of the test battery. Capacity matching, etc., such as the lithium-ion battery to the user's hand has been activated, we commonly used nickel-cadmium batteries and nickel-metal hydride batteries are also such that after the activation of the factory, some of the batteries the activation process requires the battery to be in The opening state is activated and then sealed. This process can only be completed by the core manufacturer.

There is a problem here, that is, batteries from the battery factory are delivered to the user. This time will sometimes be very long, as short as 1 month, and as long as 6 months. This time, because the battery electrode material will passivation. Therefore, the manufacturer recommends that the battery used for the first time should be fully filled 3 to 5 times in order to eliminate the passivation of the electrode material and achieve maximum capacity.

In the three national standards for nickel-metal hydride, nickel-cadmium and lithium-ion batteries promulgated in 2001, the initial capacity of the batteries was clearly stipulated, and the batteries could be placed in depth and depth five times. When one meeting the requirements, the test can be stopped, which is a good explanation of what I'm talking about.

It is also possible to call it "second activation", and "new" batteries for initial use by users perform as many deep charge and discharge cycles as possible.

However, according to my tests (for lithium-ion batteries), lithium-ion batteries with a storage period of 1 to 3 months are recycled deeply and deeply. Its capacity increase is almost non-existent, (I have a test report on battery activation in the panel area)

3, the first three times to charge 12 hours?

This problem is closely attached to the above battery activation problem, and if the factory battery is set to the user's hand, there is an electrode passivation phenomenon. In order to activate the battery to perform a deep charge cycle 3 times, the question is actually whether the deep charge is to charge for 12 hours. Then another article of mine "On the charging time of mobile phone batteries" has already answered this question.

The answer is no need to charge 12 hours.

Early cell phone nickel-metal hydride batteries may take about five hours to reach the perfect state of fullness due to the need for replenishment and trickle-down charging. However, it does not take 12 hours, and the constant current constant pressure charging characteristics of lithium-ion batteries determine that its deep charging time does not need 12 hours.

For lithium-ion batteries, some people will ask, since the current of the lithium-ion battery in the constant voltage stage is gradually decreasing, is it true when the current is small to infinity, I have drawn the current in the constant voltage phase to reduce the time. Curve, it is fitted to the curve multiple times, and it is found that this curve can be close to zero current with the function of 1/x. In actual test, because of the self-discharge phenomenon of the lithium ion battery itself, this zero current is never reachable.

Take a 600mAh battery as an example, set the off current to 0.01C (ie 6mA), its 1C charging time does not exceed 150 minutes, then set the off current to 0.001C (ie 0.6mA), its charging time may be 10 hours - -- This is impossible to obtain accurately due to the accuracy of the instrument, but the capacity obtained from 0.01C to 0.001C is calculated to be only 1,7mAh, and more than 7 hours of multi-use is exchanged for less than three thousandths. The capacity is not of any practical significance.

Moreover, there are other ways of charging, such as pulse charging, which allows lithium ion batteries to reach a limit voltage of 4 or 2 V. It does not stop the minimum current judgment stage at all. After 150 minutes, it is 100 % full, and many mobile phones are charged with pulses.

Some people have used the mobile phone to display fullness, and then use the seat charge to charge to confirm the adequacy of the mobile phone. This test method is not rigorous, and the first green light display is not a basis for detecting true fullness.

The only final way to detect the adequacy of a lithium-ion battery is to test the voltage of the lithium-ion battery when it is not charged (and does not discharge).

The real purpose of the so-called constant voltage phase current reduction is to gradually reduce the additional voltage generated by the charging current on the battery resistance. When the current is as small as 0.01 C, such as 6mA, this current is multiplied by the internal resistance of the battery (usually within 200 mm).) Only 1mV, it can be considered that the voltage at this time is a battery voltage without current.

Second, the base voltage of the mobile phone is not necessarily equal to the base voltage of the seat. The mobile phone believes that the full battery is on the seat, but the seat is not considered to be full, but it continues to charge.

4, Is the rechargeable battery in its best condition?

There is a saying that when a rechargeable battery is used properly, it will appear to be the best state in a certain cycle range, that is, the maximum capacity. In this case, sealed nickel-metal hydride batteries and nickel-cadmium batteries, if used properly (such as regular maintenance, preventing the generation and accumulation of memory effects), generally reach the maximum capacity at 100 to 200 cycles. For example, after 120 cycles of nickel-metal hydride batteries with a factory capacity of 1000 mAh, their capacity may reach 1100 mAh. I can see this description on the diagram of the loop characteristics of nickel-based batteries in the technical specifications of almost all Japanese nickel-metal hydride battery manufacturers.

The nickel-based battery has the best state and generally reaches its maximum capacity between 100 and 200 cycles.

For liquid lithium-ion batteries, there is no such cycle capacity hump phenomenon, from the lithium ion battery factory until the final battery scrap, its capacity performance is used once and for all. I have never seen the capacity of lithium ion batteries in the cycle performance has not seen the signs of a rebound.

Lithium-ion batteries are not in optimal condition.

It is worth mentioning that lithium-ion batteries are more likely to exhibit different properties due to changes in ambient temperature. At 25 to 40 degrees ambient temperature, they will show their best performance, while at low or high temperatures. His performance is greatly reduced. To make your lithium-ion battery fully display its capacity, it is necessary to pay careful attention to the use of the environment to prevent high and low temperatures, such as the mobile phone on the front desk of the car. The direct sun at noon can easily make it more than 60 degrees. The battery standby time of users in the North is the same as that of users in the South.

5, Is it true that the larger the charge current, the faster the charge?

This issue has been discussed in the article "On the charging time of mobile phone batteries." For constant current charging nickel-based batteries, it can be said that this is not entirely correct for lithium-ion batteries.

For the charging of lithium ion batteries, the constant current value of the constant current constant voltage charging method is increased within a certain current range (1.5 C ~ 0.5 C), which does not shorten the time for filling lithium ion batteries.

6, direct charging output current is equal to charging current?

This involves discussing the charging method of the mobile phone. For charging management in the mobile phone, set the output of the same direct charge (actually called the power adapter) as: 5.3 V600mA

A, charging management is the switch mode(high frequency pulse width adjustment PWM mode), this charging mode, the mobile phone does not fully use the output capacity of direct charge, direct charge work in the constant pressure section, output 5.3 V, At this point, the real charging current is adjusted by the charging management of the mobile phone, and it must be less than 600mA, usually between 300 and 400mA, at this time, The direct output current you see is not the charging current of the mobile phone. For example, many of the direct charges of Motorola have an output of 5.0 V1A. The actual use of 500 mA for charging the battery is sufficient because the battery capacity of the mobile phone is only 580 mAh.

At this time, the output current directly charged with the standard does not equal the actual charging current

B, charging management for the pulse method, this charging method, the mobile phone completely uses the direct charge current limit, that is, use 600mA on the battery, this time, the direct charge output current is the charging current.

Of course, the above refers to the constant current phase of lithium ion batteries or the charging of nickel-metal hydrogen batteries.

If the phone does not have charge management, the charge management is moved to the direct charge. For example, many CDMA mobile phones are like this. This is nothing to say. Its output is clearly written, such as output: 4.2 V500mA, this is the constant current and constant pressure of the lithium-ion battery.

7. Is a cycle of charge and discharge one less than one life?

The cycle is the use, we are using the battery, we are concerned with the use of time, in order to measure the rechargeable battery can be used for how long such a performance, the definition of the number of cycles, the actual user use is ever-changing. Because tests with different conditions are not comparable, the definition of cyclic life must be standardized if there is to be a comparison.

The national standard stipulates the conditions and requirements for the cyclic life test of lithium-ion batteries: charging at 25 degrees room temperature with a constant current constant pressure 1C charging system for 150 minutes, and discharging at a constant current 1C discharge system to 2.75 V as a cycle. When a discharge time is less than 36 minutes, the test ends and the number of cycles must be greater than 300 times.

Explanation:

This definition stipulates that the test of the cyclic life is conducted in a deep and deep way

The cycle life must exceed 300 times after execution in this mode. After that, the capacity is still more than 60 %

In fact, the number of cycles obtained by different circulation systems is completely different. For example, the above other conditions are unchanged. Only the constant voltage of 4.2V is changed to a constant voltage of 4.1V. The cycle life test of the same type of battery is performed. So, this battery is not a deep charge method. In the end, the cycle life can be increased by nearly 60%. If the cutoff voltage is increased to 3.9V, the number of cycles should be increased several times.

The idea that the cycle is one life short at a time has already been discussed by many friends, and I'm just adding that when you talk about the number of cycles, you can't ignore the conditions of the cycle.

There is no point in putting aside the rules and talking about the number of cycles, because the number of cycles is a means of detecting battery life, not an end!

Myth: Many people like to use their phone lithium-ion batteries for automatic shutdown and recharging. This is completely unnecessary.

In fact, it is impossible for the user to use the battery in accordance with the national standard test mode. No mobile phone will be turned off at 2.75 V, and its discharge mode is not a high current constant current discharge, but the pulse discharge of GSM and the usual small electric discharge. Mixed way.

There is another measure of the cycle life, that is, time, some experts have proposed that the life of a lithium-ion battery for general civilian use is 2 to 3 years, combined with the actual situation, such as the end of life with a capacity of 60 %. With the aging effect of lithium-ion batteries (see point 9), I think it is more reasonable to use time to describe the cycle life.

The charging mechanism of lead batteries is similar to that of lithium-ion batteries. It is a method of limiting current and pressure. The method of use is shallow and shallow. His life expression is time, no number of times, such as 10 years.

Therefore, for lithium-ion batteries, there is no need to use shutdown and recharging. Lithium-ion batteries are originally suitable for use by charging at any time. This is one of his biggest advantages for nickel-metal hydride batteries. Please make good use of this feature.

8, The higher the battery capacity, the better?

The higher the capacity of different models (especially different volumes), the longer the service time, regardless of the factors of volume and weight. Of course, the higher the capacity, the better.

But the same battery model, the nominal capacity (such as 600mAh) is also the same, and the actual initial capacity is different: for example, one is 660mAh, and the other is 605mAh, then 660mAh is better than 605mAh.

The actual situation may be that the high capacity is due to the increase in the initial capacity of the electrode material, and the reduction of the electrode stability, the result is that after the recycling of dozens of times, the high-capacity battery rapidly fails. The low-capacity batteries are still strong. Many domestic core manufacturers often use this method to obtain high-capacity batteries. After half a year of user use, the standby time is a mess.

The civilian AA nickel-metal hydride batteries (ie, the No. 5 battery) are generally 1400mAh, but they also have ultra-high capacity(1600mAh), and the same is true.

The price of increasing capacity is to sacrifice the cycle life. The manufacturer does not discuss the modification of the battery material. It is impossible to really "increase" the battery capacity.

9, Will full batteries be stored

One of the very bad features of lithium-ion batteries is the aging of lithium-ion batteries (or aging, referred to by foreigners as aging), which means that even if the lithium-ion batteries are stored for a period of time, even if they are not recycled, some of their capacity will be permanently lost. This is because the positive and negative electrode material of the lithium ion battery has begun its failure process, different temperatures, and battery fullness from the factory. The aging consequences are different. The following data are taken from the references [ 1] , listed as a percentage of capacity:

Storage temperature-40 % charging state-100 % charging state

0 degrees-98 % (one year later)-94 % (one year later)

25 degrees -- 96 per cent (one year later) -- 80 per cent (one year later)

40 degrees-85 % (one year later)-65 % (one year later)

60 degrees -- 75 per cent (one year later) -- 60 per cent (three months later)

It can be seen that the higher the storage temperature and the fuller the battery is, the greater the capacity loss, so long-term preservation of lithium ion batteries is not recommended, and vice versa. The manufacturer should recycle it as if it were rotten food, and users should pay close attention to the date of production of the battery.

If the user has an idle battery, experts recommend a storage level of 40 % and a storage temperature of less than 15 degrees or less.

Nickel hydride batteries and nickel-cadmium batteries are almost immune to this aging effect, and long-stored nickel-based batteries can restore their original capacity after several deep charges.

10, Would it be useful to fill the seat with green light for an additional hour after it has turned on?

The green light is only an indication. Whether it is really full or not depends on the control and judgment of the battery charging process. This issue is discussed in the case of 4.2 V lithium ion batteries.

The first is the control. The output of the control to the battery is the first constant current, and the subsequent constant pressure (the current gradually decreases).

Then it is judged that when the current is less than a certain current value, the green light is displayed because the accuracy of the modulus conversion and its own voltage accuracy are limited. The seat charge usually sets the current value to 50mA, and the green light is displayed at this time. So the battery is actually less than 10 % from its true fullness (according to my measurement, the current lithium-ion battery can reach 95 % capacity if it is powered by 50mA, and the charging acceptance capacity is greatly improved. The question is what is the seat charging going on:

A. If it continues, the charger completely shuts down the charging circuit and does not continue to perform constant voltage charging. Then it is not helpful to place it for 10 hours on the charger. Many charger design schemes are like this, such as TI (Texas Instruments). The BQ2057 series charging chip is the same as the linear LT1800 series.

B, seat charge continues to carry out constant pressure charging, and strictly control the voltage does not exceed 4.2 V, no doubt for another hour, can indeed increase the battery capacity.

C, seat charge continues to charge, but its current control is very bad, accidentally makes the battery exceed 4.2 V, and continues to run up, because the lithium ion battery can not absorb any overcharge and continue to exert current on the battery, this will cause This consequence, then overcharging occurs. This is of course a poorly designed seat filling, such as the common "egg filling" that can charge lithium ion batteries and charge nickel-metal hydride batteries.

D. There is also a charging management chip, such as Maxim's 1679 chip, which is the same as many mobile phone charging management. It uses pulsed charging. When it displays green light, the lithium-ion battery is 100% full, of course. After another hour, it will not overcharge, and obviously it is doing nothing.

The user does not actually know what the cradle is doing after the green light is on, A or B or D, it is possible that the cradle instruction does not write these things, and excludes the unqualified cradle. We should actually believe the qualified and original seat. If the green light is on, why not take it down? This does not have much impact on the user. The filling is not enough and does not affect the cycle life (as mentioned in point 7 above). 95% of the capacity is also acceptable, unless there is a lover who can analyze his own charger in depth. In that way, charging, otherwise we may wish to ------ after the green light is taken down.

11, seat charging ratio full?

There is no saying that there must be more filling than the full filling, and there is no saying that there is more filling than the full filling. What is important is whether their charging method can be the fastest and largest filling battery.

The page contains the contents of the machine translation.