What is Battery Health?
Battery testing is something that many companies must do before they can sell, but at this point there is no way to fully and comprehensively test a battery for all conditions that can occur. Battery health (SOH) cannot be accurately measured, we can only judge the condition of the battery based on some conditions we see, if the battery appears to be not particularly clear or non-existent, then basically it is impossible to determine the health of the battery.
Usually, test the battery, be sure to assess three indicators.
- Capacity, the ability to store energy
- Internal resistance, the ability to provide current, and
- Self-discharge, which reflects mechanical integrity and stress-related conditions
Some of the conditions that often occur in batteries
First of all, we must understand that the battery itself will have many similar situations appear, for example, some weaker batteries, if in a charging situation, it will generally perform better; likewise, some stronger batteries, in a low charge mode, maybe the same as a battery pack that has already experienced capacity loss. Moreover, some of our recent treatments for the battery, including charging, discharging, and long-term non-use will also affect the battery. So, when we test the battery, we must first understand, what has happened to the battery recently.
In the following picture to understand, the liquid represents the current available capacity of the battery, the rocks represent and reduce the volume of the lost capacity. The blank part represents the capacity that can be filled and the tap represents the permanent loss of capacity.
Capacity plays a decisive role in the health of the battery, it represents the energy storage, generally, if it is a new battery or battery pack, its capacity is 100%; that is, a 6AH battery pack should provide 6 amps per hour, if the battery stops in about 30 minutes, then it has 50% capacity left. The minimum health value of the battery capacity is 80%, if your battery capacity has fallen below 80%, then you will find that the battery loses power very fast, this time, you need to go to replace the battery, the battery capacity directly determines the life of the battery.
When the battery capacity begins to decline?
- Lithium battery capacity decreases very slowly, but it has begun to wear out from the time of production, although it is slower.
- Lead-acid batteries will drop very fast when there is still 85% capacity.
- After the nickel-based battery is produced, if it is not used, it needs to be recharged to reach full capacity.
The battery is like a young man getting old gradually, when he started to use it, the use time is longer, the endurance is more adequate, and the replenishment energy is faster, but as the use time gets longer and longer, the power will be lower and lower, and the charging speed will be slower and slower.
The battery is like a person who is gradually aging
When to replace the battery?
There is actually no fixed time for battery replacement, and depending on the use, the time for battery retirement is also different. Generally, a more commonly used lithium battery may last 5-10 years (for home use), and lead-acid batteries can last about the same amount of time.
Battery retirement at the same time is also dependent on the application, which makes the battery analyzer organization usually set the replacement for threshold value of 80%, there are some industries in the use of batteries will be longer, such as some scanning equipment inside the warehouse, the battery may have been as low as 60%, but because the use of each scan is relatively small, there may still be able to use a full day, car batteries, some only Supply the center console and ignition, while the car starts, but also in the continuous charging, which also leads to some times the car battery capacity has been low to 40%, but still can meet the daily work, although that the battery capacity has become very low.
There are also some places that use more, is in the military and medical industry, but often their batteries will always prematurely go to give a replacement, many manufacturers also tested the battery, but because of the special nature of the industry, can not be accurate, so usually the manufacturer will be marked the battery life of 2-3 years.
Much medical personnel found that although it has been to two or three years, for example, the remaining capacity of the battery of the defibrillator is more than 90%, which leads to, if this time to replace the battery, it will cause waste and economic loss, although this is the case, in the U.S. FDA a survey shows that the battery received inside the hospital, of which 50% of the hospital called to consult The battery will have a relationship with the battery.
What other applications for batteries?
Batteries also use a very important application in the drone, if it is using a battery with a capacity of 75% or more, the drone can usually work continuously for about an hour, but if the battery capacity has fallen below 75%, it will appear that the drone can only work for 45 minutes, if the drone does not have any low battery indication, it will be possible to fall directly from the air, causing Greater economic losses, so that the battery capacity of each battery pack is very important, we can easily close to 100% of the battery for a long time work use, the battery capacity is relatively low can be used for a period of time, so that you can fully carry out the use of the battery, if the battery capacity has been lower than 40%, it is recommended to replace the battery.
How to judge the battery capacity?
Generally speaking, we can not directly judge the battery capacity, usually, our equipment will have a power meter for the display of the remaining battery light, we are charging, generally will charge the battery power to 100%, but this may give us the illusion that the battery is always healthy, we had better pay attention to the battery use time, if the battery use If the time becomes shorter, then the battery capacity is has declined, and the health level has also declined.
The current difficulties faced by the battery
Battery currently has a great difficulty is that no matter which industry, the health of the battery can not be 100% accurate judgment out, assess the capacity is the main health indicators of the battery, more backward. Measuring open-circuit voltage and checking internal resistance does not provide conclusive evidence of the health of the battery.
Many people may wonder why it is so difficult to judge the battery because the battery diagnosis is very complex, the battery is similar to a person, there is no single analysis equipment can directly analyze the health of the whole body, (although it is said that the Chinese medicine can be detected to a certain extent, but also can not be 100% accurate, and can make a very accurate judgment of the people in the minority), there is no can quickly and reliably check There is no instrument that can quickly and reliably check the health of the whole battery, the battery may have defects in several places, any single test method can not be very accurate.
A dead battery is easy to check, and all testers are 100% accurate. The challenge is to evaluate batteries in the 80-100% performance range while they are working. Regulatory agencies struggled to introduce battery testing procedures. This is mainly because there is no suitable technology to dynamically evaluate batteries.
As in the story “The blind man touches the elephant”, shown below, each person can only feel part of the elephant’s body, which makes their judgments different.
Battery technology is developing step by step, and finally, we hope that the development of batteries can be better and better and that instruments can appear as soon as possible to help us better judge the health of batteries, so as to better save resources and protect the environment.