As the core technology of electric vehicle and renewable energy storage, power lithium battery has received extensive attention. 360V power lithium battery system has become an ideal choice for electric vehicles, power storage and other new energy applications due to its high energy density and high efficiency. This article will discuss in detail the complete design scheme of 360V lithium battery, including battery pack design, battery management system (BMS), thermal management system, charging and discharging scheme and safety design.

I. Battery pack design

1. Battery monomer selection

when designing 360V power lithium battery pack, it is first necessary to select the appropriate battery cell. Generally, power lithium batteries use lithium iron phosphate (LiFePO4), ternary lithium batteries (NMC, nickel cobalt manganese oxide), etc. For 360V system, the rated voltage of single battery is generally 3.2V (lithium iron phosphate) or 3.7V (ternary lithium battery).

Assuming that the ternary lithium battery is selected and the rated voltage of the single battery is 3.7V, the number of cells required is:

[
\text {number of battery cells} = \frac{360V}{3.7V} \approx 97
]

2. Series-parallel design of battery pack

in order to meet the demand of power and capacity, battery cells need to be combined in series and parallel. In the design of 360V, 16 single units are usually connected in series to form a series module, and then multiple modules are connected in parallel according to requirements. Assume that the capacity of each module is 100Ah. If a system capacity of 300Ah is required, three modules need to be connected in parallel.

3. Structure design of battery pack

the structural design of the battery pack should take into account factors such as battery fixing, cooling, connection and safety. Aluminum Alloy or steel shell is usually used with insulation material to ensure the safety and durability of the battery pack. At the same time, heat dissipation holes and channels should be reserved in the design to facilitate the installation of the thermal management system.

II. Battery management system (BMS)

battery Management System (BMS) is very important in the design of lithium batteries, and is mainly responsible for the monitoring, protection and management of batteries.

the BMS needs to monitor the voltage, current, temperature and SOC (battery state of charge) of the battery pack in real time. Through the analysis of these parameters, the abnormal state of the battery can be found in time to avoid overcharge, overdischarge, short circuit and other problems.

2. Protection function

BMS shall have multiple protection functions, including overcharge protection, overdischarge protection, overtemperature protection and short circuit protection. These protection functions can be realized through components such as relays, fuses and MOSFETs to ensure the safe operation of the battery pack.

3. Data Communication

BMS usually has the data communication function, which CAN transmit the status of the battery pack to the host computer or other devices through interfaces such as CAN bus or RS-485. This is of great significance to the management and maintenance of battery pack.

III. Thermal management system

power lithium battery generates heat during charging and discharging, so the design of thermal management system cannot be ignored. Reasonable thermal management system can improve the efficiency and life of the battery.

1. Active cooling system

for high power applications, active cooling systems are usually used. The system may include air cooling or liquid cooling. The air cooling system uses a fan to flow air through the battery pack and take away heat; The liquid cooling system circulates between the battery pack and the radiator through cooling liquid to achieve more efficient heat dissipation.

2. Passive cooling design

in some low-power applications, passive cooling design can be considered. Through reasonable material selection and structural design, the battery pack can naturally dissipate heat and reduce costs and complexity.

IV. Charging and discharging scheme

1. Charging scheme

the charging scheme should consider the compatibility of charging rate, charging mode and charging equipment. Constant current and constant voltage (CC-CV) charging mode is usually adopted to ensure the safety and stability of the battery during charging. In addition, the charging pile needs to communicate with the BMS to facilitate intelligent charging.

2. Discharge scheme

the size and duration of current should be considered in the design of discharge scheme. For the power battery, the SOC of the battery should be kept within a reasonable range during the discharge process to prolong the service life of the battery. Meanwhile, the monitoring and management of the current in the discharge process should also be undertaken by the BMS.

V. Security design

safety is one of the most important aspects in the design of power lithium batteries. The following are some major security design measures:

1. Mechanical protection

the shell of the battery pack should have sufficient strength and toughness to resist external shock and vibration. At the same time, the buffer structure should be designed inside the battery pack to prevent the single battery from being damaged due to vibration.

2. Temperature monitoring and control

by integrating a temperature sensor in the BMS, the temperature of the battery pack is monitored in real time. Once the temperature exceeds the set threshold, BMS should immediately start the cooling system and take corresponding protective measures.

3. Fire and explosion-proof design

power lithium battery under extreme conditions, there may be a risk of thermal runaway. Therefore, fireproof material should be considered in the design and a gas release device should be integrated into the battery pack to prevent gas accumulation from causing explosion.

The complete design scheme of 360V power lithium battery involves battery pack design, battery management system, thermal management system, charging and discharging scheme, safety design and other aspects. Through scientific and reasonable design, it can ensure that the power lithium battery has high efficiency, high safety and long-term stability, and meet the needs of electric vehicles and other new energy applications.