The grades of Lifepo4 cells are an indicator of their quality, and the information is generally required when you are searching for a battery. They are evaluated by three essential criteria – energy density, discharge voltage, and cycle life.
The higher energy and density contain, the better performance of the battery. The higher discharge voltage indicates that the power is more significant than, the lower voltage. Therefore, it is more suitable for high-power loads. In addition, it has excellent cyclic properties and can maintain over 90% of capacity after 1000 cycles. It is essential to understand the difference between the two grades of Lifepo4 cells. It will ensure you use the correct battery for your application and provide you with the expected output.
Apart from the battery’s discharge test performance, it will also be classified according to its capacity. It can fruitfully be divided into two categories: A and B. In this article, you will find the grades of Lifepo4 cells. It’ll explain how they differ, why they’re essential, and which quality suits you best.
- What Is Grade A LiFePo4 Cell?
LiFePo4 grade A cells are lithium-iron-phosphate battery cells that meet the battery’s quality standard. These battery cells don’t cause swelling or abnormal chemical reactions within them. The result is a fully functional battery with a long lifespan.
Grade A cells can be relied on for their superior performance and longevity. They have passed strict quality control procedures, ensuring the most consistent cell chemistry and electrical performance.
Grade A cell contains a clear QR code such as above
- What Is Grade B Lifepo4 Cell?
LiFePo4 grade B cells are made from the same raw material as LiFePo4 grade A cells, with strict quality control procedures. Grade B cells have not been used yet, and some may have defects.
When the defective rate of a cell increases, it can cause instability which impacts everything from charging to discharging. Beyond this, LiFePo4 grade B cells have different power consumption patterns than grade A.
It depends on the type of circuit being used. Grade B cell has energy storage, and charge/discharge capabilities are similar to the grade A cell.
Grade B cells often contain obssure QR codes
- What Reasons Occurs That Changes Cells From A Grade To B Grade?
In factories, any production process is bound to have some percentage of products that fails. It determines how much a factory can produce. In the lithium battery industry, the quality levels are not easily distinguishable from one end of the line to another.
It’s important to note that small-scale manufacturers don’t have machines that can solve the problems of their larger counterparts. Their defect rate is still reasonably high because of a lack of size and resources.
The average LiFePo4 grade B battery lasts the same time and performs the same quality. You have to pay more for a LiFePo4 grade A because it lasts significantly longer than grade B.
If a grade A cell is put in a warehouse for 3-6 months, it becomes grade B. It is why a grade B battery is created and has problems. This guideline cannot be relied on, but if the battery goes wrong, then it’s worth replacing.
How Can You Distinguish Grade A And Grade B LiFePo4 Cells?
Here’s the right way to distinguish grade A and grade B cell specifications, which are given as follows: Here’s the right way of distinguishing grade and grade B cells are their specifications, which are given as follows:
- Appearance
You can easily distinguish the grade A and B cells by their external appearance. The LiFePo4 grade A cell has the QR sticker in its original condition. The grade B cell also has the QR sticker, but it is scrapped, or sometimes it is removed.
Note: Some cells also do not contain QR codes, but they are grade A cells.
- Weight And Dimension
SOC varies by dimension and weight, which may need to be confirmed with suppliers. It typically needs to be measured at the same state of charge conditions. If there is variation in the datasheet provided by the supplier, it may be a LiFePo4 grade B cell or problem.
- Capacity Of Cells
The battery’s capacity is typically tested at 25°C, with a 1C charging and discharging rate. The accurate test result should be compared to the specifications provided.
Note: Many manufacturers of cells follow a specific number in the datasheet. When comparing the final result with the datasheet, you should be careful to find one that won’t give you a high capacity than expected when reaching the outcome of the datasheet.
- Internal Resistance
Testing conditions refer to the datasheet or ask for confirmation from the manufacturer. Different manufacturers will test AC or DC resistance at different frequencies, but generally 1000Hz. DC’s internal resistance has proven to be a more reliable option.
Note: You have LiFePo4 grade A cells if your test results match the datasheet.
- Self-Discharge Rate
The amount of charge lost from a battery is based on the amount of voltage it has and its current state. Diligence is needed to have high-quality batteries. At 100% charged, the voltage will be much lower than 50% charged. Make sure you check the datasheet before continuing SOC first.
Testing Methods
Solution One: Let liFePo4 cells for 28 days at the temperature of 25℃ to check the voltage discharge rate.
Solution Two: You can also stock liFePo4 cells for seven days at a temperature of 45℃ to check the voltage discharge rate.
- Recovery Of Capacity
To test how much battery capacity is restored, you need to perform a 100% deep discharge and re-charge. For example, if a battery cell has 3.2 volts and 100Ah and has a 95% recovery rate, you have tested its capacity to be 100Ah.
After all the testing, you then charge it 100% depth of discharge to get the capacity of more than 95Ah after all the testing.
Note: You’re planning to compare the test data with the specification of the cells. So you’ll know when to trust a datasheet or company offering it. After all your tests and comparison, if all of the data meet the specification or datasheet, they will be grade A cells. If not, it will be grade B cells.
- Furthermore, About Grade A And Grade B Cells
Supplementary point 1:
The complete bar code is not necessarily an A grade. Some refurbished batteries also have a complete original bar code like grade A, which the test results should judge.
Supplementary point 2:
The names of A and B in the market are perplexed. As long as the brand-new cells meet the specifications and standards and are called grade A in the market, grade B refers to those with apparent problems or renovations.
Grade A and B, classified by the manufacturer, refer to brand-new batteries, and the classification standards of each manufacturer are different.
Therefore, as long as the qualified batteries are tested at the above points, they can be used, mainly depending on the application. If used for power batteries, they must be the manufacturer’s positive grade A, and brand-new grade B batteries without performance problems can be used for household energy storage or other energy storage purposes.
Grade A batteries are recommended for those who only pursue quality and don’t care about price.
