With the continuous advancement of global energy conservation and emission reduction policies, new energy heavy trucks (hereinafter referred to as "heavy trucks"), as an important force of green transportation, are gradually replacing traditional fuel vehicles, become the mainstream choice in the field of logistics and heavy haul transportation. The core component supporting the efficient operation of new energy heavy truck is its power battery system. Whether it is a pure electric heavy truck or a hybrid heavy truck, the power battery system can be called the "heart" of the whole vehicle, which directly determines the endurance, power performance and service life of the vehicle. This article will focus on the power battery system of pure electric and hybrid heavy truck for in-depth analysis to help readers fully understand this key technology.

I. Definition and function of new energy heavy truck power battery system

the power battery system of new energy heavy truck, as its name implies, refers to the battery pack and its management system that provide electric energy for vehicles. It mainly completes the functions of storing electric energy, releasing power and ensuring safety, and is an important foundation for vehicle power transmission.

• For pure electric heavy truck, the power battery system is the only power source of the vehicle and undertakes all driving tasks.
• For hybrid heavy truck, the power battery system works together with the internal combustion engine to realize energy saving, emission reduction and power optimization through the complementary power between the motor and the engine.

Power battery system not only affects the mileage and acceleration performance of vehicles, but also relates to safety, use cost and later maintenance, which is the core link of the development of new energy heavy truck technology.

II. Composition and structure of power battery system

generally speaking, the power battery system of new energy heavy truck mainly includes the following parts:

1. battery cell and battery module
   the power battery consists of a large number of battery cells (usually lithium ion batteries), and multiple cells are reasonably combined to form a battery module. The battery module then synthesizes the vehicle battery pack through the structural design group.
   The choice of battery monomer directly affects the energy density, service life and safety performance of the battery.

2. Battery Management System (BMS)<br /> The battery management system is the "brain" of the power battery, which is responsible for monitoring the battery voltage, current, temperature and other parameters to ensure that the battery runs within a safe range; At the same time, it realizes charge and discharge management, fault diagnosis and balanced charging extend battery life.

3. Cooling and thermal management system
   when the heavy truck runs at high load, the battery pack will generate a lot of heat, and a reasonable thermal management system ensures the stable temperature of the battery to avoid performance degradation or safety risks caused by overheating. Common cooling methods include liquid cooling and air cooling.

4. Structure and protection system
   battery pack must have good mechanical strength and protective performance to resist vibration, impact and environmental erosion and ensure battery safety.

III, power battery system technical features

1. high energy density
   energy density is a key indicator to measure battery performance, which is directly related to battery life. Currently, heavy trucks mostly use lithium iron phosphate (LiFePO4) or ternary lithium batteries, which have their own advantages in energy density and safety. Ternary lithium battery has higher energy density, which is helpful to prolong life; While lithium iron phosphate battery is famous for its safety and stability and longer cycle life.

2. Long service life design
   the heavy truck battery system needs to meet the requirements of long-term and high-intensity use, and the battery life directly affects the operating cost. By optimizing battery materials, battery management and thermal management technologies, the cycle life of new energy heavy truck power batteries has reached more than 2,000 times, some of which can reach 3,000 times, meeting the needs of long-distance transportation.

3. Security Performance
   the safety of power batteries is particularly important. Battery system design includes multiple safety protection mechanisms, such as short circuit protection, over temperature protection, over charge and over discharge protection, etc., to minimize potential safety hazards.

4. Fast charging capability
   heavy truck operation requires efficient energy supplement, and supporting fast charging technology has become an important indicator of power battery system. With the improvement of charging facilities and the progress of battery technology, some heavy truck power batteries can be charged to more than 80% within 30 minutes.