Opportunity
Lithium batteries are widely used due to their high energy density, fast charging speed, and long lifespan. However, a critical challenge during charging is the formation of multilayer lithium dendrites, which can lead to internal short circuits, reduced Coulombic efficiency, and diminished cycle life. Traditional charging methods, such as constant-current or trickle charging, often result in uneven lithium deposition and weak solid-electrolyte interphase (SEI) layers. These issues exacerbate dendrite growth, compromising battery safety and performance. Existing techniques fail to dynamically adjust charging currents to suppress dendrite formation effectively, creating a need for an innovative charging strategy that ensures uniform lithium deposition and enhances battery longevity.
Technology
This patent introduces a novel charging control method for lithium batteries based on a bell-shaped current curve. The key innovation lies in dynamically adjusting the charging current to follow a predefined bell-shaped curve, which ensures the battery’s capacity grows along an S-shaped curve. The S-curve is modeled by the logistic function \( y = \frac{K}{1 + e^{-(a + bt)}} \), where \( y \) is the charging capacity, \( K \) is the maximum capacity, and \( a \), \( b \) are constants. The charging current is derived from the differential equation \( \frac{dy}{dt} = -\frac{b(K - y)}{K} \), ensuring gradual current changes—low initial/final currents and a peak mid-charge current. This approach strengthens the SEI layer, promotes uniform lithium deposition, and minimizes dendrite formation. The method supports both fixed and gradient-decreasing maximum capacity (\( K \)), adapting to different battery conditions.
Advantages
- Suppresses lithium dendrites: Prevents internal short circuits by promoting uniform lithium deposition.
- Enhances Coulombic efficiency: Optimizes charge transfer, reducing energy loss.
- Extends cycle life: Improves battery durability by maintaining stable SEI layers.
- Adaptive charging: Supports fixed or dynamically adjusted capacity limits for flexibility.
- High safety: Low initial/final currents reduce thermal stress and degradation.
Application
- Electric vehicles (EVs): Prolongs battery lifespan and safety in high-demand applications.
- Portable electronics: Ensures efficient charging for smartphones, laptops, and wearables.
- Energy storage systems: Enhances reliability in grid-scale or residential battery systems.
- Medical devices: Provides stable power for implantable or critical-care equipment.
- Aerospace: Improves performance in satellites and drones where battery failure is costly.
