\u2461SEI Film Rupture and Repair<\/p>\n\n\n\n
The SEI film on the negative electrode surface repeatedly ruptures and repairs during cycling. This process continuously consumes electrolyte and generates gas.<\/p>\n\n\n\n
\u2462Reaction of Moisture and Impurities<\/p>\n\n\n\n
Moisture or metallic impurities introduced during the production process can react chemically with the electrolyte, producing gases such as hydrogen.<\/p>\n\n\n\n
Cause of Shell Bulging 2: Improper Use<\/h3>\n\n\n\n
\u2460Overcharging and Over-discharging<\/p>\n\n\n\n
Prolonged charging leading to overcharging, or continuing to use the battery after it’s completely depleted leading to over-discharging, will exacerbate internal side reactions and accelerate gas production.<\/p>\n\n\n\n \u2461Using Inferior Chargers<\/p>\n\n\n\n Non-original or inferior chargers cannot accurately control voltage and current, easily leading to battery overcharging and damaging battery life.<\/p>\n\n\n\n \u2462High-Temperature Environments<\/p>\n\n\n\n Charging or using the battery in high-temperature environments will accelerate electrolyte decomposition and SEI film damage, significantly increasing the gas production rate.<\/p>\n\n\n\n \u2460Manufacturing Process Defects<\/p>\n\n\n\n Process defects during manufacturing, such as electrode burrs, separator wrinkles, and inadequate sealing, can lead to internal micro-short circuits or moisture ingress, posing inherent risks to battery bulging.<\/p>\n\n\n\n \u2461Battery Aging and High Temperature Effects<\/p>\n\n\n\n With increased usage time, the active materials inside the battery are depleted, internal resistance increases, the SEI film thickens, and internal side reactions intensify. High-temperature environments (such as exposure to direct sunlight) accelerate this process, ultimately leading to increased gas production and bulging.<\/p>\n\n\n\n \u246090-120\u00b0C: SEI Film Decomposition<\/p>\n\n\n\n SEI film decomposition releases initial heat and gas, triggering the reaction.<\/p>\n\n\n\n \u2461130-180\u00b0C: Separator Melting and Short Circuit<\/p>\n\n\n\n Separator melting causes direct contact between the positive and negative electrodes, initiating an internal short circuit and a rapid temperature rise.<\/p>\n\n\n\n \u2462150-250\u00b0C: Positive Electrode Decomposition and Oxygen Production<\/p>\n\n\n\n Positive electrode material decomposes, releasing oxygen, which reacts violently with the electrolyte, accelerating the temperature rise.<\/p>\n\n\n\n \u2463Final Result: Combustion and Explosion<\/p>\n\n\n\n The electrolyte burns, causing the battery to burn or even explode, resulting in serious consequences.<\/p>\n\n\n\n \u2460Mechanical Abuse<\/strong><\/p>\n\n\n\n The battery is subjected to external impacts such as collisions, compression, or punctures, leading to internal structural damage and short circuits.<\/p>\n\n\n\n \u2461Electrical Abuse<\/strong><\/p>\n\n\n\n The battery experiences electrical anomalies such as overcharging, over-discharging, or external short circuits, causing internal reactions to run out of control.<\/p>\n\n\n\n \u2462Thermal Abuse<\/strong><\/p>\n\n\n\n The battery is exposed to high temperatures, or the cooling system fails, causing heat to accumulate and triggering thermal runaway.<\/p>\n\n\n\n In a battery pack, thermal runaway from a single cell can rapidly spread to other cells, creating a “domino effect.” This propagation primarily occurs through three mechanisms:<\/p>\n\n\n\n \u2460Heat Conduction:<\/strong> The high-temperature cell directly transfers heat to adjacent cells via metal components.<\/p>\n\n\n\n \u2461Heat Radiation:<\/strong> The high-temperature cell heats the surrounding environment and other cells through infrared radiation.<\/p>\n\n\n\n \u2462Heat Convection:<\/strong> The flow of high-temperature gases within the battery pack diffuses heat to other areas.<\/p>\n\n\n\n \u2460Selecting High-Stability Materials<\/p>\n\n\n\n Materials with higher thermal stability are preferred, such as LFP batteries, whose thermal runaway temperature is generally higher than that of NMC batteries, thus reducing the risk of fire from the source.<\/p>\n\n\n\n \u2461Optimize battery structure design<\/p>\n\n\n\n Adopt innovative structures and technologies to improve impact resistance, optimize spatial layout, and enhance the overall stability of the battery pack.<\/p>\n\n\n\n \u2462Multiple safety devices have been added.<\/p>\n\n\n\n A built-in explosion-proof valve allows for directional pressure relief when pressure is too high; a fuse device is designed to automatically cut off the circuit in the event of a short circuit to prevent heat spread.<\/p>\n\n\n\n \u2460BMS<\/p>\n\n\n\n As the “brain” of the battery, the BMS is responsible for monitoring the voltage, current, and temperature of each cell in real time, performing active balancing, predicting fault risks, and initiating protective measures (such as cutting off power) in case of abnormalities.<\/p>\n\n\n\n \u2461High-efficiency thermal management system<\/p>\n\n\n\n Uses liquid cooling, air cooling, and other methods to control the battery operating temperature within the optimal range (typically 25-40\u2103), preventing localized overheating and suppressing the occurrence and propagation of thermal runaway.<\/p>\n\n\n\n Use original or certified chargers and avoid overcharging or over-discharging.<\/p>\n\n\n\n Avoid high temperatures, humidity, or direct sunlight.<\/p>\n\n\n\n Do not disassemble, squeeze, or puncture the battery.<\/p>\n\n\n\n Discontinue use immediately if you notice any abnormalities such as bulging or overheating.<\/p>\n\n\n\n <\/p>","protected":false},"excerpt":{"rendered":" What is battery casing bulging? Definition of Phenomenon During use or storage, gas buildup inside a battery causes increased pressure, leading to expansion and deformation of the casing. Internal Mechanism This is a macroscopic manifestation of an abnormal chemical reaction occurring inside the battery and is one of the important indicators of battery failure. Potential […]<\/p>\n","protected":false},"author":1,"featured_media":2692,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-2691","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"yoast_head":"\n<\/figure>\n\n\n\n
Causes of Battery Bulging 3: Manufacturing Defects and Aging<\/h3>\n\n\n\n
<\/figure>\n\n\n\n
The Essence of the Explosion: Thermal Runaway<\/h3>\n\n\n\n
Three Triggering Conditions for Thermal Runaway<\/h3>\n\n\n\n
Thermal Runaway Propagation: Domino Effect<\/h3>\n\n\n\n
Preventive measure 1: Material and design optimization<\/h3>\n\n\n\n
<\/figure>\n\n\n\n
Preventive measure 2: Intelligent monitoring and thermal management<\/h3>\n\n\n\n
<\/figure>\n\n\n\n
Preventive measure 3: Use according to regulations<\/h3>\n\n\n\n