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(Two)What's The Frequently Asked Questions About The Battery ?

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(Two)What's The Frequently Asked Questions About The Battery ?
Latest company news about (Two)What's The Frequently Asked Questions About The Battery ?

 

This article is Herculesi original article, if you need to copy, please contact: david@herculesi.com, or by phone: +86-13632987139.

Do not copy without permition,Unauthorized duplication is a violation of applicable laws.

 

The Frequently Asked Questions About The Battery?

 

21. What is the standard charge and discharge of NiMH batteries?

The IEC international standard stipulates that the standard charge and discharge of nickel-metal hydride batteries is: first discharge the battery to 1.0V / support at 0.2C, then charge at 0.1C for 16 hours, put it on for 1 hour, then put it at 1.0C / support at 0.2C, ie To charge and discharge the battery standard

 

22. What is pulse charging? What is the impact on battery performance?

Pulse charging is generally carried out by charging and discharging, that is, charging for 5 seconds, and then discharging for 1 second, so that the oxygen generated by the charging process is mostly reduced to an electrolyte under the discharge pulse. It not only limits the amount of vaporization of the internal electrolyte, but also gradually restores or approaches the original capacity after charging and discharging 5-10 times using the charging method for those old batteries that have been heavily polarized.

 

23. What is trickle charging?

Trickle charging is used to compensate for the loss of capacity due to self-discharge after the battery is fully charged. Pulse current charging is generally used to achieve the above objectives.

 

24. What is charging efficiency?

Charging efficiency refers to the measure of the amount of chemical energy consumed by a battery during its charging process into a chemical energy that can be saved by the battery. Mainly affected by the battery process and the working environment temperature of the battery, the higher the general ambient temperature, the lower the charging efficiency.

 

25. What is the discharge efficiency?

 

Discharge efficiency refers to the ratio of the actual amount of electricity discharged to the rated voltage discharged under a certain discharge condition to the rated capacity. It is mainly affected by factors such as discharge rate, ambient temperature, internal resistance, etc. Under normal circumstances, the higher the discharge rate, The lower the discharge efficiency. The lower the temperature, the lower the discharge efficiency.

 

26. What is the output power of the battery?

The output power of a battery refers to the ability to output energy in a unit of time. It is calculated based on the discharge current I and the discharge voltage, P = U * I, in watts.

The smaller the internal resistance of the battery, the higher the output power, the internal resistance of the battery should be less than the internal resistance of the electrical appliance, otherwise the power consumed by the battery itself is greater than the power consumed by the electrical appliance, which is uneconomical and may damage the battery.

 

27. What is the self-discharge of the secondary battery? What is the self-discharge rate of different types of batteries?

Self-discharge, also known as charge retention, refers to the ability of the battery to store electricity under certain environmental conditions in an open circuit state. In general, self-discharge is primarily affected by manufacturing processes, materials, and storage conditions. Self-discharge is one of the main parameters for measuring battery performance. In general, the lower the battery storage temperature, the lower the self-discharge rate, but it should also be noted that if the temperature is too low or too high, the battery may be damaged and cannot be used.

After the battery is fully charged and left on for a period of time, a certain degree of self-discharge is normal. The IEC standard stipulates that the nickel-hydrogen battery is fully charged and has an open circuit for 28 days at a temperature of 20 ° C ± 5 ° C and a humidity of (65 ± 20) %. The 0.2 C discharge capacity reaches 60% of the initial capacity.

 

28. What is the 24-hour self-discharge test?

The self-discharge test of a lithium battery is:

Generally, 24-hour self-discharge is used to quickly test its charge retention capability. The battery is discharged to 3.0V at 0.2C, constant current and constant voltage 1C is charged to 4.2V, and the off current is 10mA. After being left for 15 minutes, it is discharged to 1C at 1C. V measures its discharge capacity C1, and then charges the battery constant current constant voltage 1C to 4.2V, off current: 10mA, after 1 hour of hold, 1C capacity C2, C2/C1*100% should be greater than 99%.

 

29. What is the difference between the internal resistance of the charge state and the internal resistance of the discharge state?

The internal resistance of the charge state refers to the internal resistance when the battery is fully charged 100%; the internal resistance of the discharge state refers to the internal resistance after the battery is fully discharged.

Generally speaking, the internal resistance of the discharge state is not stable, and is too large, the internal resistance of the charge state is small, and the resistance value is relatively stable. In the use of the battery, only the internal resistance of the charge state has practical significance. In the later stage of the battery use, the internal resistance of the battery will increase to different degrees due to the depletion of the electrolyte and the decrease of the activity of the internal chemical substance.

 

30. What is a static resistance? What is dynamic resistance?

The static internal resistance is the internal resistance of the battery during discharge, and the dynamic internal resistance is the internal resistance of the battery during charging.

 

31. Is the standard overcharge test?

The standard overcharge test for nickel-metal hydride batteries specified by the IEC is:

The battery was discharged to 1.0 V/branch at 0.2 C, and continuously charged at 0.1 C for 48 hours. The battery should be free of deformation and liquid leakage, and the time for discharging 0.2 C to 1.0 V after overcharging should be greater than 5 hours.

 

32. What is the IEC standard cycle life test?

The IEC standard nickel-hydrogen battery standard cycle life test is: after the battery is placed at 0.2C / 1.0V / support

01) Charge at 0.1C for 16 hours, then discharge at 0.2C for 2 hours and 30 minutes (one cycle)

02) 0.25C charging for 3 hours and 10 minutes, discharging at 0.25C for 2 hours and 20 minutes (2-48 cycles)

03) 0.25C charging for 3 hours and 10 minutes, to 0.25C to 1.0V (49th cycle)

04) Charge at 0.1 C for 16 hours, set aside for 1 hour, and discharge 0.2 C to 1.0 V (50th cycle). For nickel-metal hydride batteries, after repeating 1-4 for 400 cycles, the 0.2 C discharge time should be greater than 3 hours; for nickel-cadmium batteries, repeat 1-4 for 500 cycles, and the 0.2 C discharge time should be greater than 3 hours.

 

33. What is the internal pressure of the battery?
Refers to the internal air pressure of the battery, which is caused by the gas generated during the charging and discharging process of the sealed battery, and is mainly affected by factors such as battery material, manufacturing process, and battery structure. The reason for this is mainly due to the accumulation of gas inside the battery and the gas generated by the decomposition of the organic solution in the battery. Generally, the internal pressure of the battery is maintained at a normal level. In the case of overcharge or overdischarge, the internal pressure of the battery may increase:
For example, overcharge, positive: 4OH- - 4e → 2H2O + O2↑; 1
The generated oxygen reacts with the hydrogen evolved on the negative electrode to form water 2H2 + O2 → 2H2O 2
If the rate of reaction 2 is lower than the rate of reaction 1, the generated oxygen is too late to be consumed, resulting in an increase in the internal pressure of the battery.

 

34. What is the standard charge retention test?
The IEC specifies the standard charge retention test for NiMH batteries: after the battery is placed at 1.0V to 1.0V, it is charged at 0.1C for 16 hours, and stored at a temperature of 20 °C ± 5 °C and a humidity of 65% ± 20%. After 28 days, discharge to 1.0 V at 0.2 C, while the NiMH battery should be greater than 3 hours.
The national standard stipulates that the standard charge retention test for lithium batteries is: (IEC has no relevant standard) The battery is placed at 3.0C to 3.0/branch, and then charged to 4.2V with a constant current of 1C, the off current is 10mA, and the temperature is 20 At °C±5°C, after 28 days of storage, discharge to 0.25V at 0.2C to calculate the discharge capacity, which should be no less than 85% of the initial capacity compared with the nominal capacity of the battery.

 

35. What is a short circuit test?
Connect the fully charged battery to the positive and negative terminals with a wire with internal resistance ≤100mΩ in the explosion-proof box. The battery should not explode or ignite.

 

36. What is the high temperature and high humidity test?
The high-temperature and high-humidity test of Ni-MH battery is as follows: after the battery is fully charged, it is stored under constant temperature and humidity conditions for several days, and no leakage occurs during storage.
High-temperature and high-humidity test of lithium battery: (national standard) Charge 1C constant current and constant voltage to 4.2V, cut off current 10mA, then put in (40±2) °C, relative humidity of 90%-95% constant temperature and humidity After leaving the box for 48 hours, the battery was taken out and placed at (20 ± 5) °C for 2 hours. The appearance of the battery should be observed without abnormality, and then discharged at a constant current of 1 C to 2.75 V, and then at (20 ± 5) °C. , 1 C charging, 1 C discharge cycle, until the discharge capacity is not less than 85% of the initial capacity, but the number of cycles is not more than 3 times.

 

37. What is the temperature rise experiment?
After the battery is fully charged, it is placed in an oven, and the temperature is raised from room temperature at a rate of 5 ° C / min. The oven temperature is maintained at 130 ° C for 30 minutes, and the battery should not explode or ignite.

 

38. What is the temperature cycle experiment?
The temperature cycling experiment consists of 27 cycles, each consisting of the following steps:
01) The battery is switched from normal temperature to 66±3°C and placed at 15±5% for 1 hour.
02) Switch to a temperature of 33 ± 3 ° C, humidity of 90 ± 5 ° C for 1 hour,
03) Condition changed to -40 ± 3 ° C, placed for 1 hour
04) The battery is left at 25 ° C for 0.5 hours.
After 4 steps, the battery should be leak-free, climbing alkali, rust or other abnormal conditions.

 

39. What is the drop test?
After the battery or battery pack is fully charged, it is dropped from a height of 1 m three times onto the concrete (or cement) floor to obtain a random direction impact.

 

40. What is a vibration experiment?
The nickel-hydrogen battery vibration test method is:
After the battery was discharged to 1.0 V at 0.2 C, it was charged at 0.1 C for 16 hours, and after being left for 24 hours, it was vibrated

under the following conditions:
Amplitude: 0.8 mm The battery was vibrated between 10 Hz and 55 Hz and was incremented or decremented at a rate of 1 Hz per minute. The battery voltage should be within ±0.02V and the internal resistance should be within ±5mΩ. (Vibration time is 90min)
The lithium battery vibration test method is as follows: after the battery is discharged to 3.0V at 0.2C, the 1C charge constant current constant voltage is charged to 4.2V, the off current is 10mA, and after being left for 24 hours, the following is as follows:
Conditional vibration: A vibration experiment was performed with a vibration frequency of 10 Hz to 60 Hz and then 10 Hz for a cycle with an amplitude of 0.06 inches. The battery vibrates in the triaxial direction and vibrates for half an hour per axis. The battery voltage should be within ±0.02V and the internal resistance should be within ±5mΩ.

 

This article is Herculesi original article, if you need to copy, please contact: david@herculesi.com, or by phone: +86-13632987139.

Do not copy without permition,Unauthorized duplication is a violation of applicable laws.

Pub Time : 2019-04-15 16:12:25 >> News list
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