Whether it is the design of the battery pack or the use of lithium batteries in digital devices, buying a best lithium battery is crucial. So, what kind of lithium battery is a good battery?
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The life of rechargeable lithium batteries includes two indicators: cycle life and calendar life.
Cycle life means that after the battery has experienced the number of cycles the lithium battery manufacturer promises, the remaining capacity is still greater than or equal to 80%.
Calendar life means that regardless of whether it is used, its remaining capacity shall not be less than 80% within the period the manufacturer promises.
Battery cycle life is one of the key indicators of power batteries. On the one hand, the big act of replacing the battery is troublesome, and the user experience is not good. On the other hand, battery life is also a cost issue.
The concept is “full life cycle cost of electricity.” The total power of the power battery multiplied by the number of cycles is the total amount of power that can be utilized throughout the battery’s life cycle. Divide the total price of the battery pack by this sum to get the price per kilowatt-hour of electricity over the entire life cycle.
The battery prices we usually talk about, such as 1,500 RMB/kWh, are only priced based on the total energy of the new battery cells. The full life cycle cost of electricity is the direct benefit of end customers.
The most intuitive result is buying two battery packs with the same capacity at the same price. It reaches the end of its life after charging and discharging 50 times. The other can be used again after being charged and discharged 100 times. Of these two battery packs, it’s clear which is cheaper and which is more expensive.
The price per kilowatt hour of lithium battery is low, which is the most intuitive cost. In addition to what was said earlier, whether the cost is really low for users depends on the “full life cycle cost of electricity.”
In addition to the above two costs, battery maintenance costs must also be considered. The maintenance of the battery cells themselves mainly refers to manual balancing.
The built-in balancing function of the lithium battery BMS is limited by the size of its designed balancing current. It may not be able to achieve the ideal balance between cells. Over time, the problem of excessive pressure difference will occur in the lithium battery pack. In such a situation, you have to perform manual equalization and charge the cells separately with too low voltages. The less frequently this occurs, the lower the maintenance costs.
Energy density refers to the energy contained in unit weight or unit volume.
Power density refers to the value of the maximum discharge power corresponding to unit weight or volume.
However, there is a certain contradictory relationship between energy density and safety. As energy density increases, security will always face newer and more difficult challenges.
The ratio of the energy released during the discharge process of a lithium battery to the energy charged into the battery from 0 before this discharge is called Coulombic efficiency.
The efficiency is mainly related to the internal resistance of the battery.
Compared with other types of rechargeable batteries, the charge and discharge efficiency of lithium batteries is relatively high, generally above 98%. Therefore, this parameter is often not mentioned much.
Because the negative electrode materials of lithium batteries use graphite electrodes. The material properties of the cathode material mainly determine the voltage of a lithium battery. The upper voltage limit of lithium iron phosphate battery is 3.6V. The maximum voltage of ternary lithium and lithium manganate batteries is about 4.2V.
Developing high-voltage batteries is a technical route for improving the energy density of lithium batteries. To increase the output voltage of the cell, a cathode material with a high potential is required. Anode material with low potential and electrolyte with high stable voltage.
Lithium batteries have good high-temperature performance, which means that the battery’s positive and negative electrode materials, separators, and electrolytes can maintain stability when the battery core is in a higher-temperature environment. Lithium battery packs can work normally at high temperatures, and their lifespan will not accelerate. High temperatures are less likely to cause thermal runaway accidents.
The safety risks of lithium batteries largely come from high temperatures. Generally, the maximum operating temperature of lithium batteries is around 50°C. In particular, it can reach 60℃.
The SEI film on the surface of the negative electrode can begin to dissolve at around 90°C. This causes the battery core to enter the self-heating stage. Self-generated heat brings additional temperature rise; if not stopped in time, there will be a risk of thermal runaway.
Lithium batteries have good low-temperature performance, which means that the lithium ions and electrode materials inside the battery maintain high activity at low temperatures. And the remaining capacity is high. The discharge capacity decreases. It also allows for large charging rates.
As the temperature drops, the remaining capacity of lithium batteries decays at an accelerated rate. The lower the temperature, the faster the capacity decays. Forced charging at low temperatures is extremely harmful and can cause thermal runaway accidents.
At low temperatures, the activity of lithium ions and electrode active materials decreases, and the rate of lithium-ion embedding into the anode material seriously decreases. When an external power supply is used to charge the battery at a power exceeding the battery’s allowable power, many lithium ions accumulate around the negative electrode. The lithium ions that have no time to embed in the electrode receive electrons and are directly deposited on the surface of the electrode to form lithium elemental crystals. The dendrites grow, directly penetrate the separator, and pierce the positive electrode. This causes a short circuit between the positive and negative poles, leading to thermal runaway. Lithium elements are active in nature and can react violently at around 180°C. It is undoubtedly a booster for thermal runaway.
Consistency means that cells used in the same battery pack have very small differences in parameters such as capacity, open circuit voltage, internal resistance, and self-discharge and have similar performance. Suppose the cell monomers with excellent performance are not consistent. In that case, their excellence will often be wiped out after being grouped.
Studies have shown that the capacity of the battery pack after being assembled is determined by the minimum capacity cell, and the battery pack life is shorter than the life of the shortest cell.
The safety of lithium batteries includes both the stability of the internal materials and the effectiveness of battery cell safety auxiliary measures.
The safety of internal materials refers to the positive and negative electrode materials, separators, and electrolytes. They have good thermal stability and compatibility between the electrolyte and electrode materials, and the electrolyte has good flame retardancy.
Safety auxiliary measures refer to the battery core’s safety valve design, fuse design, temperature-sensitive resistor design, and appropriate sensitivity. After a single cell fails, it can prevent the fault from spreading and play an isolation role.
Lithium batteries have high energy density. To prevent excessive energy at a single point, battery cells generally have small energy. Batteries used in electric vehicles require many cells to be organized and connected as a whole.
The single cells are welded, crimped, and other methods are used to form modules, and the modules are connected through high-voltage wires to form a battery pack. In this process, whether the individual cells are easy to weld, whether the connection interface is designed for crimping, and whether the thermal management system is convenient for each battery cell will affect the group design’s simplicity and the group’s efficiency.
Some battery cells have high density per cell, but their shape is unfriendly. After being processed into a battery pack, the energy density is only half of the cell’s. Suppose the connection characteristics of the battery cells are not good. In that case, the energy density of the battery cells will be wasted.
Using the above rulers to measure the quality of lithium battery cells and using the checklist to check key items of lithium batteries is a simple and effective way to judge the quality of the best lithium batteries.
As a world-renowned lithium battery customization manufacturer, Ufine has focused on the research, development, production, and sales of customized lithium batteries for many years, providing customers worldwide with detailed and optimal solutions.
Now the market is full of lithium battery of various sizes and brands, and many users are trying them out with a trial mentality. However, some users report that the effect of the battery is not satisfactory. Next, We will tell you how to choose the battery correctly, and teach you a few ways to judge the quality of the battery. Selecting the right battery cells for your device can ensure that it operates effectively and safely.
Before you purchase a battery for your device, it’s important to understand your device’s battery requirements.
The manual or website for your device should provide information on the recommended or required battery type, size, and capacity for your device. For example, if you’re looking to replace the battery in your cell , the manual may indicate that the device requires a lithium-ion battery with a specific voltage and capacity.
Power consumption is a crucial factor to consider when selecting a battery for your device. Look at the device’s power consumption and calculate how long you want the battery to last. This can help you determine the required capacity of the battery. For example, if you’re using a flashlight for an extended period, you’ll need a battery with a high capacity to ensure it lasts for the duration of your use.
Make sure the battery’s voltage output matches the device’s requirements. Using a battery with a different voltage can damage the device or cause it to malfunction. For example, if your device requires a 3.7-volt battery, using a battery with a higher voltage can cause overheating or damage to the device’s circuits.
Some devices have limited space for a battery or have weight limitations, so it’s important to select a battery that fits within these limitations. For example, if you’re looking for a battery for a drone, you’ll need to consider the weight of the battery, as it can impact the drone’s flight time and stability.
Link to CHANGINGTECH
There are various battery types available, each with their pros and cons. Lithium-ion batteries are commonly used in electronic devices due to their high capacity, low self-discharge rate, and light weight. Alkaline batteries are commonly used in low-power devices such as remote controls and flashlights. NiMH batteries are rechargeable and commonly used in high-power devices such as digital cameras. By comparing the pros and cons of each type, you can select the best battery for your device.
After clearly understanding your device or your design, we need to learn how to judge the quality of lithium batteries.
Some people think that the key indicator of the battery is the service life of the battery, but all indicators need to be based on the premise of safety. If there is no safety guarantee in the application of lithium battery, then for us, it is equivalent to a threat to life.
When purchasing a battery, check whether the lithium battery has a circuit protection board(PCB). The characteristics of the lithium battery determine that it must be equipped with a protection board to avoid overcharging, over discharge, short circuit, etc. of the lithium battery.
If there is no protective plate, the biggest danger of this kind of battery is deformation, explosion and leakage. Although with technology get better and some lithium batteries will not catch fire and make big explosion, some potential problems still exist which will decrease the service time of lithium batteries such as short circuit, over discharge and over charge and so on. In addition, rechargeable lithium battery packs without protective plates are also vulnerable to the influence of the external environment.For example, when the temperature is too high or too low, the performance and life of the battery pack will be affected to varying degrees.The protection board can improve the stability and safety of the battery pack by controlling the charging and discharging process of the battery pack.
According to the current batteries on the market (lead-acid batteries, lithium batteries, LiFePO4 batteries, Li-PO batteries), LiFePO4 batteries maybe are safer and do not deflagrate easily.
Different capacity, power, and last time will directly lead to a large difference in the price of electric vehicles.
At present, the more common lithium batteries are 12V 20Ah, 24V 30Ah, 48V 40Ah and other different sizes. Not only denpend on common size , but also depends on whether the capacity of the battery is accurately marked. If it is not marked, it is likely to be an inferior battery.
Why?
This kind of battery may be reassembled from inferior batteries or recycled battery cells. Don’t blindly pursue low prices. This kind of battery has a short life and unstable performance. If it is used improperly, it is very likely to damage the equipment. Oh, for example: Catching Fire.
The battery capacity will gradually decrease as it is used for a longer period of time, and the range of electric vehicles will become shorter and shorter. Therefore, if you want a longer service life, choose one with a larger battery capacity. Of course, you need a little more budget.
The safety hazards of lithium batteries are also related to the internal pressure, structure, process design and other reasons of the battery. When we want to judge the quality of lithium batteries, it mainly depends on the workmanship, size and craftsmanship. For batteries with the same capacity, lithium-ion batteries feel lighter than nickel-metal hydride batteries and nickel-cadmium batteries.
After observising the lithium battery, we can touch then. In general, we need to judge whether the seams of the battery shell are tight or not, and whether there are burrs or oil stains or not.
From this aspect, it can also be indirectly inferred whether the battery is prone to leakage.
The cycle life refers to the number of repeated charges and discharges that the battery can experience, and the charge and discharge conditions have a great impact on it. The greater the charging current (the faster the charging speed), the shorter the cycle life; the deeper the discharge depth, the shorter the battery life.According to the newly formulated electric vehicle battery standard, the life of the battery is expressed by the number of charge and discharge cycles of a certain capacity of 70%, and the qualified bottom line is 500 times.
Sometimes people find it strange that the electric car is obviously fully charged. Why is the battery dead after being left there for a period of time without riding?
In fact, this is due to the self-discharge rate of the lithium battery. Normally, when we store our lithium batteries correctly, the stored capacity will drop around 0.5 to 3% per month. If the reduced value exceeds the range, then the battery is not normal.
Examples of applying these considerations:
1. CELL BATTERY REPLACEMENT
Let’s say you have a Samsung Galaxy S21 that requires a mAh battery with a voltage of 3.85V. The battery capacity is measured in milliampere-hours (mAh), and it indicates the amount of charge the battery can hold. The voltage specifies the electric potential difference between the positive and negative terminals of the battery.
To calculate the wattage of the battery, you can use the formula: Wattage = Voltage x Current. In this case, the wattage of the battery would be 15.4 watts (3.85V x 4A). This calculation helps you determine how much power the battery can deliver to your device.
2.FLASHLIGHT BATTERY SELECTION:
Let’s say you have a flashlight that requires a battery with a voltage of 3.7V and a capacity of mAh. The flashlight’s power consumption is 6 watts, and you want the battery to last for at least 4 hours.
To determine the required capacity of the battery, you can use the formula: Capacity (in Ah) = Power (in watts) x Time (in hours) / Voltage (in volts). In this case, the required capacity of the battery would be 0.648 Ah (6W x 4h / 3.7V). You would need a battery with a capacity of at least 648 mAh to power the flashlight for 4 hours.
To calculate the wattage of the battery, you can use the formula: Wattage = Voltage x Current. In this case, the wattage of the battery would be 11.1 watts (3.7V x 3A). This calculation helps you determine how much power the battery can deliver to your device.
3. DRONE BATTERY SELECTION:
Let’s say you have a DJI Mavic Air 2 drone that requires a battery with a voltage of 11.55V and a capacity of mAh. The drone’s weight is 570 grams, and you want the battery to last for at least 30 minutes.
To determine the required capacity of the battery, you can use the formula: Capacity (in Ah) = Power (in watts) x Time (in hours) / Voltage (in volts). In this case, the required capacity of the battery would be 1.91 Ah (123.75W x 0.5h / 11.55V). You would need a battery with a capacity of at least mAh to power the drone for 30 minutes.
To calculate the wattage of the battery, you can use the formula: Wattage = Voltage x Current. In this case, the wattage of the battery would be 40.425 watts (11.55V x 3.5A). This calculation helps you determine how much power the battery can deliver to your device.
4.BOAT BATTERY SELECTION:
Let’s say you have a 24-volt trolling motor on your boat that requires two 12-volt batteries. The motor draws a maximum current of 30 amps and you want the batteries to last for at least 6 hours.
To determine the required capacity of each battery, you can use the formula: Capacity (in Ah) = Current (in amps) x Time (in hours). In this case, the required capacity of each battery would be 180 Ah (30A x 6h / 2). You would need two batteries with a capacity of at least 180 Ah each to power the trolling motor for 6 hours.
To determine the required capacity of each battery in watt-hours, you can use the formula: Capacity (in Wh) = Voltage (in V) x Capacity (in Ah). In this case, the required capacity of each battery would be 2,160 Wh (12V x 180 Ah). You would need two batteries with a capacity of at least 2,160 Wh each to power the trolling motor for 6 hours.
To calculate the wattage of each battery, you can use the formula: Wattage = Voltage x Current. In this case, the wattage of each battery would be 360 watts (12V x 30A). This calculation helps you determine how much power the battery can deliver to your device.
5. RC BATTERY SELECTION:
Let’s say you have a high-performance RC car that requires a LiPo (Lithium Polymer) battery with a voltage of 14.8V and a capacity of mAh. The car draws a maximum current of 60 amps, and you want the battery to provide maximum power output.
To determine the required capacity of the battery, you can use the formula: Capacity (in Ah) = Current (in amps) x Time (in minutes) / 60. In this case, the required capacity of the battery would be 50 Ah (60A x 5 min / 60). You would need a LiPo battery with a capacity of at least 50 Ah to power the RC car.
To calculate the wattage of the battery, you can use the formula: Wattage = Voltage x Current. In this case, the wattage of the battery would be 888 watts (14.8V x 60A). This calculation helps you determine how much power the battery can deliver to your device.
In conclusion, When choosing the right battery for your device, it’s important to consider factors like capacity, voltage, size, weight, and cost. By understanding the specifications and performance of these popular battery types, you can make an informed decision and ensure optimal performance for your electronic devices.
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