Lithium battery has become the dominant energy solution for portable electronic devices, power tools, new energy vehicles and large-scale energy storage systems due to its excellent electrochemical performance. Its core advantages are reflected in:
High specific energy characteristics
Energy density per unit volume/weight far exceeds that of traditional batteries
Significantly reduce equipment weight and improve battery life
Long cycle life
Can be repeatedly charged and discharged hundreds to thousands of times
Effectively reduce long-term use costs
Environmental adaptability
No memory effect, flexible charging and discharging
No heavy metal pollution sources such as lead/cadmium
This article will systematically analyze the lithium battery:
⚡ Working principle (ion migration mechanism)
🔬 Technical classification (divided by material system)
📊 Key performance parameters (voltage/capacity/internal resistance, etc.)
🌐 Evolution of application fields (from microelectronics to grid-level energy storage)
Core structure of lithium battery
The core structure of lithium battery is composed of battery cell and protection board. As an energy carrier, the battery cell contains five layers of functional materials:
The positive electrode uses lithium cobalt oxide (LiCoO₂), lithium manganese oxide (LiMn₂O₄), ternary nickel cobalt manganese (LiNiₓCoᵧMn₂O₂) or lithium iron phosphate (LiFePO₄), which releases lithium ions during charging and accepts lithium ions during discharging;
The negative electrode is mainly composed of graphite or silicon-carbon composite material, which embeds lithium ions during charging and releases lithium ions during discharging;
The electrolyte is used as an ion conduction medium, the liquid system uses lithium salt organic solution (such as LiPF₆), and the polymer system uses gel electrolyte;
The diaphragm is a polyolefin microporous membrane (PE/PP) or a ceramic composite membrane, which blocks electronic conduction but allows lithium ions to penetrate;
The shell provides mechanical sealing, cylindrical batteries are mostly steel shells, square batteries use aluminum shells, and soft-pack batteries use aluminum-plastic composite films.
The protection board (BMS) serves as the control center:
The protection chip monitors voltage/current/temperature in real time, triggering overcharge, over-discharge, overcurrent and over-temperature protection;
MOS tube performs circuit on-off control;
Resistors and capacitors form a filter circuit to improve stability;
PCB substrate integrates all components. Special-shaped batteries are adapted to special space layouts through flexible circuit design.
Working principle and life mechanism
Lithium batteries achieve energy conversion through the migration of lithium ions between positive and negative electrodes ("rocking chair mechanism"):
Charging process: The external power source drives lithium ions to be deintercalated from the positive electrode, migrate to the negative electrode through the electrolyte, and electrons compensate for the charge through the external circuit. Fast charging is limited by the diffusion rate of lithium ions and the risk of negative electrode dendrite formation.
Discharge process: Lithium ions are removed from the negative electrode and returned to the positive electrode, and electrons supply power to the load through the external circuit. Deep discharge can cause irreversible damage such as thickening of the negative electrode solid electrolyte interface (SEI) film.
The cycle life depends on the material system:
Lithium iron phosphate (LFP) can withstand 2000-5000 cycles (capacity retention rate 80%);
The life of ternary materials (NCM/NCA) is 800-1500 times;
Lithium cobalt oxide (LCO) is usually 500-800 times. The main reasons for life attenuation include the collapse of the positive electrode structure, the decomposition of the electrolyte and the continuous growth of the SEI film.
Classification system
Lithium batteries are classified according to four dimensions:
Charge and discharge characteristics: disposable batteries (such as lithium-manganese dioxide CR series) and rechargeable batteries;
Physical structure:
Cylindrical batteries (such as 18650/21700) have high mechanical strength;
Square aluminum shell batteries have excellent space utilization;
Soft pack batteries can achieve lightweight special-shaped designs;
Chemical system:
Lithium cobalt oxide (LCO) has high energy density and is used in consumer electronics;
Ternary materials (NCM/NCA) balance energy density and cost and dominate the electric vehicle market;
Lithium iron phosphate (LFP) has become the first choice for energy storage and commercial vehicles with ultra-high safety;
Performance-specific type: high-rate battery (supports instantaneous high current of drones), wide temperature range battery (-40℃~85℃ working conditions).
Key performance parameters
Capacity: The total amount of energy storage is measured in mAh or Wh, which determines the battery life of the device;
Voltage: The nominal value of 3.6V/3.7V corresponds to the 50% power working point, which affects the circuit compatibility;
Internal resistance: The unit is mΩ, and low internal resistance ensures high power output and low temperature rise;
Rate performance: The ratio of charge and discharge current to rated capacity (C-rate), 1C means that the power is fully discharged in 1 hour;
Cycle life: The number of cycles at which the capacity decays to 80% of the initial value, which is related to the full cycle use cost.
Application field panorama
Lithium batteries cover six major scenarios with high energy density and long life:
Mobile devices: Smart phones and laptops rely on their compact energy storage;
Power tools: Provide high-power pulse current to drive electric drills and lawn mowers;
Electric transportation: Electric vehicles/electric bicycles rely on power battery packs to achieve long battery life;
Renewable energy storage: Photovoltaic/wind power systems use lithium batteries to balance grid fluctuations;
Aerospace: Drones and satellites require lightweight and high-energy power supplies;
Medical and emergency systems: Defibrillators and emergency lighting rely on their reliable discharge.
The logic of technological evolution
The development of lithium batteries follows a three-level optimization path:
Material innovation: developing single crystal positive electrodes, silicon-carbon negative electrodes and solid electrolytes to improve energy density;
Structural breakthrough: CTP (Cell to Pack) technology eliminates modules to improve space utilization;
Intelligent management: AI-BMS system realizes health status prediction and safety warning.
As a manufacturer specializing in lithium polymer batteries, LYW focuses on innovation and continuously brings customers affordable high-quality batteries. Its products are widely used in various scenarios and have received unanimous praise from customers. If you have any needs, you can contact the online customer service or call us, we will provide you with the best service
