In today’s global energy storage, battery performance plays a crucial role in our everyday lives. We rely heavily on their battery life to stay connected and productive throughout the day. However, with the increasing demands of modern applications and features, optimizing battery performance has become more important than ever.
In this blog, we will explore definition of battery performance, lithium ion battery performance and how to optimize battery performance.
What is battery performance?
Battery performance refers to the overall capability of a battery to supply electrical energy effectively and reliably over a specific period. The performance of batteries is inherently diverse due to variations in types and technologies.
When consumers purchase batteries, they often encounter detailed performance parameters on the product packaging. These specifications offer valuable insights into the battery’s characteristics, including voltage, capacity, and other pertinent data.
These parameters, along with additional details such as cycle life, charge and discharge rates, self-discharge rates, temperature sensitivity, efficiency, and safety features, collectively define the battery’s performance profile.
What does battery performance include?
- Ah (ampere hours)
Reflects the battery capacity. For example, 48V100Ah means the battery capacity is 4.8 kilowatt hours. Nominal voltage and nominal ampere-hours are the most basic and core concepts of batteries. Electricity Wh=power W*hour h=voltage V*ampere-hour Ah - C (battery discharge C rate)
Reflects the battery charge and discharge capacity rate. Charge and discharge rate = charge and discharge current/rated capacity. A measure of the speed of discharge. Generally, the capacity of the battery can be detected through different discharge currents. For example, when a battery with a battery capacity of 100A·h is discharged at 15A, its discharge rate is 0.15C. - DOD (Depth of Discharge) depth of discharge
Refers to the percentage of the capacity released by the battery to the rated capacity of the battery during battery use. For the same battery, the set DOD depth is inversely proportional to the battery cycle life. When improving performance in one aspect, performance in other aspects will be sacrificed. For example: when DOD is 80%, the cycle life of lithium battery can reach 6,000 ~ 12,000 times.
- SOC (State of charge)
Indicates the remaining battery power as a percentage of the battery’s rated capacity. - SOH (State of Health)
Battery health status (including capacity, power, internal resistance, etc.) is the ratio of the capacity released by the battery from the fully charged state to the cut-off voltage at a certain rate and its corresponding nominal capacity. To put it simply, it is the ratio of performance parameters to nominal parameters after the battery has been used for a period of time. A new factory battery is 100%, and a completely scrapped battery is 0%. According to the IEEE standard, after a battery has been used for a period of time, the capacity of the battery when it is fully charged Below 80% of rated capacity, the battery should be replaced.
Lithium-ion battery performance features
Lithium-ion battery energy storage as one of the most efficient and cost-effectiveness ways to store energy. Here are some battery performance features of it.
- Turnover efficiency: Cycle efficiency shows how efficient a battery is over a complete charge and discharge cycle. For lead batteries, this is typically around 75%. This means that if you charge a 1000Wh lead acid battery, you will only get 750Wh to actually power your device. So the battery alone loses 25% of the system efficiency! In the case of solar street lights (or any other solar system) this means at least 25% more solar panels are needed to power the same load. Under these conditions, the system will inevitably become more expensive (or perform worse with the same configuration). However, for lithium batteries, the cycle efficiency is about 98%. As a result, the use of this battery technology has increased.
- Discharge depth tolerance and discharge cycle: The depth of discharge is related to the depth of discharge of the battery in each cycle. The more deeply a battery is discharged, the fewer the discharge cycles and therefore the shorter the battery’s life. Lithium batteries can be easily discharged to 95%, while lead batteries are limited to less than 50%. If you want to use the battery for about 2000 cycles (2000/365 days = 5, 5 years), the lead battery can only be discharged 25-35%, while the lithium battery can only be discharged about 80%. This means you need at least 4 times the capacity of a lithium battery to get the same battery life as a lead battery!
- The complexity of lithium batteries: Lead batteries are easier to implement than lithium batteries. Lithium batteries are more sensitive to overcharge (above the maximum allowable voltage) and discharge (below the minimum allowable voltage), which requires more advanced electronic equipment. So these conditions continue to drive all related products to be equipped with dedicated battery management systems that can optimize charging and discharging to maximize battery life.From many aspects, lithium batteries have better battery performance than lead-acid batteries, which also establishes the indispensable position of lithium batteries in application fields. Due to the complexity of lithium batteries, battery management systems are gradually derived to continuously ensure the safety and efficiency of battery applications.
Possibility of optimizing battery performance
As one of the pioneers of modern technology, lithium batteries are constantly promoting changes in our lifestyles. By continuously increasing energy density, extending cycle life, and accelerating charge and discharge rates, we can achieve more efficient and reliable ways to store electricity. Next we will discuss the details about optimizing battery performance.
Increase energy density:
Energy density is one of the important indicators for measuring the performance of lithium batteries. It determines the amount of energy stored per unit volume or unit mass of the battery.
In order to increase energy density, we can take the following measures:
- Battery material optimization: Improve the energy storage capacity of batteries by developing higher-capacity positive and negative electrode materials, such as lithium cobalt oxide, lithium iron phosphate, silicon, etc.
- New electrolyte research: Explore electrolytes with higher ionic conductivity and wider voltage windows to increase battery energy density.
Extend cycle life:
Battery cycle life refers to the number of charge and discharge cycles a battery can undergo while maintaining good performance.
In order to extend cycle life, we can consider the following methods:
- Battery Management System (BMS): Reasonably controls charge and discharge current and voltage, monitors temperature and battery status to provide the best charge and discharge strategy.
- Smart charging algorithm: Adopt advanced charging algorithms, such as a combination of constant current charging and constant voltage charging, to reduce charging time and reduce the cycle load of the battery.
- Temperature control: Maintain the battery within a suitable temperature range to avoid the impact of too high or too low temperature on battery life.
Speed up the charging and discharging rate:
The charge and discharge rate refers to the speed at which the battery releases or absorbs energy per unit time.
Increasing the charge and discharge rate enables fast charging and high power output. Here are some key methods:
- New electrode material design: Use materials with better conductivity and improve the electrode structure to increase the charge transfer rate and ion diffusion speed.
- Nanostructure and porosity: Introduce nanomaterials and porous structure to increase the electrode surface area and increase the ion diffusion speed.
- Charging infrastructure upgrade: Optimize charging equipment and grid architecture to provide a higher-power fast charging environment.
+86 – 18925002618
