HF-Bewegung 
Rechargeable Battery Types and Principles
The market offers several types of rechargeable batteries for residential/commercial energy storage, solar powered battery, portable power station, usw. Like lithium iron phosphate, ternary lithium, liquid lead-acid, colloidal lead-acid, and more. These batteries work by storing and releasing energy through chemical reactions that undergo repeated oxidation and reduction within the battery.
A rechargeable battery comprises three main parts: The positive electrode, the negative electrode, and the electrolyte. The electrolyte separates the positive and negative electrodes, which allows ions to move between them. When charging, an external power source sends current into the battery. This process causes ions in the positive electrode to oxidize while those in the negative electrode reduce, thereby increasing the stored energy. Conversely, during discharge, the battery releases current. This leads to the reduction of ions in the positive electrode and oxidation of ions in the negative electrode, resulting in decreased stored energy within the battery.
Battery Life
A battery undergoes a cycle when it’s drained from 100% Zu 0% and then recharged back to 100%. The cycle life of a battery refers to how many times it can handle this process before its capacity decreases to 80% of its original under specific charging and discharging conditions, like discharge current, temperature, cut-off voltage, usw.
Different rechargeable batteries have varied cycle lives. Zum Beispiel, ternary lithium batteries can endure around 1,500 Zyklen, lithium iron phosphate batteries up to 2,000 Zyklen, while lead-acid batteries manage only about 800 Zyklen.
Factors Affecting Battery Life
Various factors influence the battery cycle life, like depth of discharge, state of charge, charge/discharge rate, number of cycles, and temperature.
Number of Cycles
As the battery undergoes more cycles, its performance and lifespan gradually decline. It’s important to note that cycles don’t equate to the number of charges.
Depth of Discharge (DoD)
This refers to the percentage of battery discharge relative to its rated capacity. A DoD of 100% means the battery is fully discharged, while 0% signifies a full charge. To optimize battery life, aim for shallow discharges (25%~75% range) rather than deep discharges. Charging and discharging in smaller increments is preferable over depleting the battery completely and then recharging. Shallow discharges generally extend the battery’s cycle life compared to deep discharges.
State of Charge (SoC)
It indicates the remaining capacity of the battery compared to its full capacity, measured in electricity. SoC at 0% signifies the battery is completely drained, while 100% means it’s fully charged. Voltage is directly linked to power: higher power corresponds to higher voltage. Low voltage delays calendar aging and cycle aging.
Charging and discharging within a low-power (voltage) range, at the same discharge depth, tends to extend the battery’s lifespan compared to high-power (voltage) ranges. Prolonged high SoC can accelerate the precipitation of lithium ions, reducing active lithium ions and diminishing battery capacity. Conversely, extended low SoC can accelerate the consumption of the negative solid electrolyte interface (SEI) film. This can lead to the dissolution of the negative electrode copper foil, forming copper dendrites, and accelerating battery degradation
Charge-discharge Rate
This measures the current flow during charge and discharge relative to the battery’s rated capacity, reflecting how quickly the battery charges or discharges. Zum Beispiel, if a battery is charged within one hour, the average charging rate is 1C; charging within 30 minutes indicates a 2C rate. Fast charging above 1C can shorten battery lifespan. Discharge rates are generally mild and typically don’t pose concerns.
Temperature
High temperatures increase the activity of the battery’s electrolyte and active materials, leading to side reactions and electrolyte decomposition. This accelerates capacity loss and may generate gas, causing swelling. Conversely, low temperatures increase the electrolyte’s viscosity, slowing lithium ion conductivity. This mismatch in electron migration speeds in the circuit causes severe polarization, significantly reducing charge and discharge capacity. Charging at low temperatures can prompt lithium precipitation and dendrite formation on the negative electrode’s surface, dramatically reducing the battery’s critical temperature and heightening the risk of thermal runaway.
Ways and Issues to Extend Battery Life
The cycle life of a battery has limitations, but proper usage can slow down capacity decay, extending the battery’s lifespan. To achieve this, consider the following:
- Reduce the number of cycles.
- Keep depth of discharge above 65% of the battery capacity.
- Avoid depth of charging to full capacity.
- Minimize fast charging times, and lower the charging currents.
- Employ Intelligent Battery Management Systems (BMS) to regulate charging currents based on different stages.
- Maintain a reasonable temperature range.
Jedoch, implementing these strategies might pose challenges based on usage scenarios. Batteries are crucial in situations where mains power isn’t available or where mobile power is necessary without connections. In such cases, extending battery life by reducing cycles and discharge depth becomes difficult.
Be it industrial, kommerziell, or household use, batteries often need charging before usage. Solar cells, for instance, undergo constant charging and discharging due to system processes. This continuous cycle significantly impacts battery capacity and leads to a reduced cycle life, often falling below the nominal number of cycles.
The Best Way to Extend Battery Life
Then we found the fundamental problem. The core issue lies in how batteries are primarily used as backup power sources. When used solely for backup, the frequency and depth of charge and discharge are substantially reduced, affecting the battery’s cycle life differently.
At HF Motion, we’ve introduced an innovative solar cell system which named E-Hybrid solar technology. This innovative approach integrates batteries into the solar system, enabling direct output of solar energy to the load. In this setup, the battery serves as a backup, rather than being the sole conduit for outputting energy to the load.
We offer solutions and products for residential, industrial, and commercial solar systems, incorporating this pioneering technology.
Its operating mode is as follows:
In the described operational mode, the system primarily functions as Solar → Loads, occasionally transitioning to Solar + Battery → Loads or Battery → Loads. Jedoch, there’s never a direct flow from Solar → Battery → Loads. This avoids the problem that the system needs to charge the battery before output.
Beyond the mentioned systems, we also offer portable solar powered battery that incorporate E-Hybrid technology alongside MPPT modules and inverters. These units feature lithium iron phosphate batteries with capacities ranging from 1000 to 2000Wh. They cater to various scenarios like household electricity, outdoor camping, and field operations.
The unique design allows direct output of solar energy to the load whenever sunlight is available, unter Umgehung der Batterie. Even when the battery is low, sunlight enables direct output to the load, disregarding battery power. This approach significantly extends battery lifespan compared to conventional mobile power supplies. It ensures consistent power output across diverse settings, providing stable performance regardless of the environmental conditions.
