A lithium battery pack is not just a simple assembly of batteries. It is a highly integrated and precise system project. It covers multiple steps, including cell selection, structural design, thermal management, and safety protection. This guide will show you the complete process from design and manufacturing to testing and safety, offering practical and valuable reference.
Contents
What is a Lithium Battery Pack?
A lithium battery pack is an integrated battery system. It is built by connecting many individual cells in series and parallel. It includes a Battery Management System (BMS), reliable electrical connections, and a protective structural package. Through scientific design and strict manufacturing control, the battery pack’s safety, reliability, and service life are well guaranteed.
Compared to a single battery cell, a lithium battery pack offers higher energy density and can be used in more applications. However, it also requires more advanced management technology and stronger safety measures.
Currently, lithium battery packs are widely used in electric vehicles, home backup storage, solar energy storage systems, uninterruptible power supplies (UPS), communication base stations, and various types of industrial equipment. They provide stable and reliable power support for many different situations.
45 kwh Lifepo4 Battery Application
Guide For Lithium Battery Pack Design and Assembly
Step 1: Cell Selection and Matching
Cell Performance Consistency
The performance and safety of a battery pack first depend on cell selection. You must ensure the cells are highly consistent in key parameters like voltage, internal resistance, and capacity. If there are big differences between the cells, it will cause imbalances during charging and discharging. This not only speeds up the overall aging of the battery but may also create safety risks.
Cell Type Selection
Lithium Iron Phosphate and NMC are two mainstream lithium battery types. Their chemical systems are different, and their characteristics have different focuses. You can make a choice based on the actual use (such as electric vehicles, energy storage systems, consumer electronics, etc.). This allows you to better balance energy density, safety, cost, and service life. Delong Energy uses grade A lifepo4 cells from famous brands like BYD, CATL.
Grade A Battery Cells
Step 2: Mechanical Structure Design
Mechanical Structure Design
During design, you need to focus on the battery pack’s size, weight, and shape. You must ensure it fits your product perfectly. For example, if used in an electric vehicle, the battery pack must fit the vehicle’s space precisely. At the same time, using a high-strength structural design can resist impact from collisions. This ensures safety during use.
Lightweighting and Strength Balance
You can choose lightweight materials like aluminum alloy or carbon fiber to reduce the battery pack’s weight. Using topology optimization design improves structural rigidity. This prevents damage to the cells from vibration or impact. As a result, it extends the battery pack’s service life.
Modular Design
The battery pack uses a modular design. Each battery module is relatively independent. This not only makes the production process more efficient. It also makes later maintenance and replacement simpler and faster. Even if one module fails, it does not affect the entire system’s normal operation. This improves reliability. At the same time, you can easily expand the capacity based on your actual needs. This gives you greater flexibility.
Stackable battery easy installation
Step 3: Electrical Connections
Welding and Connection Technology
In battery assembly, the cell tabs are usually connected using advanced processes like laser welding, ultrasonic welding, or resistance welding. This not only ensures a strong connection and good conductivity. It also achieves low resistance and high reliability. At the same time, the design of the connecting pieces is optimized. This makes the current path more reasonable. It minimizes heat generation to the greatest extent.
Wiring Harness Layout
In battery system design, wiring harness layout is very important. By properly planning the paths of high-voltage wires (like the main positive and negative cables) and low-voltage signal wires (like temperature sensors and BMS communication lines), you can effectively reduce electromagnetic interference (EMI). It also helps avoid potential short-circuit risks.
Insulation and Protection
By using insulating materials to cover the connection parts of the battery system, it effectively prevents creepage and breakdown. At the same time, the battery design meets IP rating standards, providing water and dust resistance. This ensures the battery remains safe and stable even in complex environments, extending its overall service life.
Step 4: Thermal Management
Heat Dissipation Design
It uses liquid cooling, air cooling, or phase change materials (PCM) to control battery temperature. For example, electric vehicle battery packs use liquid cooling plates or coolant pipes. This ensures even temperature during charging and discharging, and helps maintain charging speed and range stability.
Heating Design
In cold environments, we use PTC heaters or electric heating films to warm up the battery. This helps avoid performance loss caused by low temperatures. No matter how the weather changes, you can enjoy stable and reliable battery power.
Thermal Simulation and Optimization
Using CAE thermal simulation technology, we can simulate the temperature changes of the battery pack in various usage scenarios in advance. It helps us precisely optimize the heat dissipation structure and prevent local overheating. This makes your battery more durable.
Step 5: Battery Management System (BMS)
Data Collection and Monitoring
The BMS monitors cell voltage, temperature, current, and other parameters in real time, so you can always know the battery status. At the same time, it uses algorithms to estimate SOC (state of charge) and SOH (state of health), helping you manage battery use safely and efficiently.
Balancing Control
By using passive balancing (resistor discharge) or active balancing (energy transfer) technology, the voltage differences between cells can be removed, which helps extend your battery life.
Safety Protection
To keep you safe, the system sets protection limits for over-charge, over-discharge, over-temperature, and short circuit. When protection is triggered, the circuit cuts off automatically. This prevents accidents from growing and keeps the battery and equipment safe and reliable.
Smart BMS For Lifepo4 Battery
Step 6: Safety Measures
Electrical Safety
A high-voltage interlock (HVIL) design is used to ensure the high-voltage system automatically cuts off during maintenance. At the same time, pre-charge resistors are installed to prevent power-on surges and protect both the equipment and user safety.
Mechanical Safety
The battery uses a burst disc and pressure release channel. If a cell overheats, this design quickly releases gas. It helps lower the risk of an explosion.
Environmental Safety
The battery meets protection standards such as IP67 and IP6K9K, preventing water and dust from entering. It also passes strict tests for salt spray, vibration, and impact to make sure it works stably and reliably even under harsh conditions.
Step 7: Testing and Validation
Electrical Performance Testing
Through charge and discharge tests, internal resistance tests, cycle life tests, and other checks, we ensure that each battery pack performs stably and reliably, fully meeting the design requirements.
Safety Testing
By simulating extreme conditions like nail penetration, compression, overcharge, and short circuit, we check the safety of the battery pack and make sure it stays reliable even in abnormal situations.
Environmental Adaptability Testing
We test the battery pack under high temperature, low temperature, high humidity, and high altitude to ensure its reliability.
51.2V Lifepo4 Vertical Energy Storage System Test
Step 8: Future Trends in Battery Pack Assembly
Wireless BMS
By using wireless communication technology instead of traditional wiring, you can reduce weight and cost while improving maintainability.
CTP/CTC Technology
By directly integrating the cells into the battery pack or chassis, you can skip the module buffer step, improving space use and energy density.
AI Algorithm Application
By using machine learning to optimize cell balancing, fault prediction, and health management, the battery pack becomes smarter and more efficient.
Conclusion
Lithium battery PACK manufacturing is a complex process that combines electrochemistry, mechanics, electronics, and thermal management. Its core goal is to use the cells’ performance to the fullest while ensuring safety and reliability.
With the rapid growth of the new energy vehicle and energy storage markets, PACK technology is evolving toward higher energy density, lower cost, and smarter designs, becoming a key driver of industry progress. Therefore, you need to be very careful when choosing a manufacturer and controlling the process.
Delong Energy has 14 years of experience in the lithium battery industry, dedicated to providing reliable and efficient energy solutions. We are a trusted partner. Contact us to get efficient solutions.
Delong – Lithium Battery Energy Storage System Factory
