With the wide application of portable electronic products, lithium ion batteries, as their main power source, have increasingly strict requirements in terms of performance and safety. In order to ensure the safety of consumers, China released the national standard GB 31241-2014 "safety requirements for lithium-ion batteries and battery packs for portable electronic products" in 2014, which aims at the design of lithium-ion batteries and battery packs, manufacturing and testing put forward the safety specifications of the system. This article will focus on the core content and key security requirements of GB 31241-2014 to help relevant enterprises and users deeply understand the importance of this standard and its specific implementation details.

I. Overview of standards

GB 31241-2014 standard is called "safety requirements for lithium ion batteries and battery packs for portable electronic products", mainly aiming at mobile phones, notebook computers, digital cameras, lithium-ion batteries and battery packs used in portable electronic products such as portable audio and video equipment. This standard defines the safety design principles, manufacturing process requirements and necessary safety testing methods of lithium batteries, aiming at minimizing the safety risks of lithium batteries during use, transportation and storage.

The standard is applicable to lithium ion batteries and battery packs with rated voltage not exceeding 24V, covering portable battery systems with different capacities and structural forms. Through standardized safety requirements, GB 31241-2014 provides technical basis for quality control and safety supervision of lithium battery products.

II. Basic Safety Design requirements

1. Materials and manufacturing processes

the standard requires battery manufacturers to select high-quality electrode materials, electrolyte and diaphragm to ensure the chemical stability and mechanical strength of the materials. In the manufacturing process, impurities should be strictly controlled to prevent the occurrence of internal short circuit and hidden danger of thermal runaway. At the same time, the connecting parts and shell materials in the battery pack must have good mechanical properties and corrosion resistance to cope with vibration and collision in daily use.

2. Structural Safety Design

the battery and battery pack shall be designed with effective isolation and protection measures to prevent internal short circuit and external impact from affecting the battery performance and safety. The standard clearly requires that there must be appropriate insulation and fixed structure between battery cells to avoid internal damage caused by vibration or extrusion.

3. Electrical protection mechanism

GB 31241-2014 stipulates that lithium batteries and battery packs should be equipped with necessary electrical protection devices, including over-charge protection, over-discharge protection, over-current protection and temperature protection. The battery management system (BMS) must have the ability to accurately monitor the battery status, respond to abnormal situations in a timely manner, and prevent the deterioration of battery performance and even cause safety accidents.

4. Thermal Management design

in view of the sensitivity of lithium ion batteries to temperature changes, the standard requires the battery pack to design a reasonable heat dissipation scheme to avoid local overheating. Through material selection and structural design, ensure that the battery maintains a stable working temperature range when charging and discharging and changing ambient temperature.

III. Safety performance test requirements

in order to verify lithium ion battery and the safety performance of battery pack, GB 31241-2014 formulated detailed test items and methods, covering electrical, mechanical and environmental aspects.

1. Electrical safety test

• overcharge test: simulate the safety performance of the battery under abnormal charging conditions and detect whether there is a risk of cracking, burning or explosion.
• Over-discharge test: verify the stability of the battery under low voltage to prevent internal damage caused by extreme discharge.
• Short circuit test: Assess the battery's short-circuit prevention capability and thermal runaway risk through internal and external short-circuit tests.
• Overcurrent test:Check the safety protection effect of the battery in the overcurrent state.
• Insulation Resistance Test: Ensure the electrical insulation performance of the battery and battery pack to prevent leakage and electric shock.

2. Mechanical safety test

• vibration Test: simulate mechanical vibration during transportation and use, and detect the stability of battery structure.
• Impact test: evaluate the safety of the battery in accidental collision through drop or impact tests.
• Extrusion test: test the safety performance of the battery under forced extrusion to prevent failure caused by mechanical deformation.
• Puncture test: evaluate the safety of the battery when it is pierced by sharp objects to prevent internal short circuit.

3. Environmental adaptability test

• high and low temperature test: ensure that the battery remains safe and stable in extreme temperature environment.
• Damp heat test: simulate the high humidity environment and detect the corrosion resistance and electrical safety of the battery.
• Salt Spray Test: check the corrosion prevention of battery shell and connecting partsCorrosion capability to ensure long-term use safety.

4. Thermal runaway test

for the abnormal risk of lithium ion batteries, the standard requires thermal runaway simulation tests to evaluate the reaction and safety performance of the batteries in extreme thermal environments. By detecting the rising rate of battery temperature, pressure release and gas emission, it is judged whether the battery has the possibility of explosion or combustion.

IV. Identification and specification requirements

GB 31241-2014 also stipulates the identification and instruction contents of lithium ion batteries and battery packs to ensure that users can correctly identify and use the products safely.

1. Product identification

the battery must be marked with the manufacturer's name, model, rated capacity, rated voltage, production date and certification mark conforming to the standard. Through clear identification, it is convenient for regulatory authorities and consumers to carry out product traceability and quality supervision.

2. Instruction manual

instructions should be detailedRight usage of the battery, charging precautions, safety warnings, storage conditions and disposal suggestions. Special emphasis is placed on avoiding high temperature, mechanical damage, incorrect link and other behaviors that may lead to safety accidents.

V. Significance of standard implementation

the implementation of GB 31241-2014 has greatly improved the security level of lithium ion batteries for portable electronic products. Through strict design and testing requirements, the standard effectively reduces the risks of fire and explosion accidents caused by overheating, short circuit, mechanical damage, etc. of lithium batteries, and protects the safety of consumers' lives and property. At the same time, the standard promotes the technological progress and product quality improvement of the industry, and promotes the standardized development of the lithium battery industry.

In addition, GB 31241-2014 provides scientific testing basis for relevant regulatory agencies, which is helpful to strengthen market supervision and product quality control, prevent unqualified products from entering the market, and protect consumers' rights and interests.

GB 31241-2014 "safety requirements for lithium ion batteries and battery packs for portable electronic products" is an important national standard covering the whole process of design, manufacture and testing of lithium batteries. The standard ensures the safety and reliability of lithium ion batteries for portable electronic products under various service conditions through strict specifications on material selection, electrical protection, mechanical structure and environmental adaptability. For production enterprises, compliance with this standard is the basis for improving product competitiveness and market recognition; For users, it is an important guarantee for safe use of portable electronic devices.