Why is Your Marine Lithium Battery Sooo Hot? —— Thermal Runaway
Maybe you think thermal runaway is very far from your marine lithium battery because you are in the sea or river which are in a quite temperature. Do not ignore some small points.What is Thermal Runaway?
Thermal runaway refers to the chain reaction phenomenon caused by various triggers, which causes the battery to emit a lot of heat and harmful gases in a short period of time, and in severe cases it can even cause the battery to catch fire and explode. There are many reasons for thermal runaway, such as overheating, overcharge, internal short circuit, collision, etc. Battery thermal runaway often starts from the decomposition of the negative electrode SEI membrane in the battery cell, and then the diaphragm decomposes and melts, resulting in a reaction between the negative electrode and the electrolyte, followed by the decomposition of the positive electrode and the electrolyte, causing a large-scale internal short circuit, causing the electrolyte to burn, and then spread to other batteries, causing serious thermal runaway, causing the entire battery pack to spontaneously ignite.
Some people make an experiment about thermal runaway of a LiFePO4 battery and they give out some characteristics of the thermal runaway flue gas of lithium iron phosphate battery: the amount of flue gas is small, the release rate is low, and no oxygen is released. According to experiment data, we can know that:
1. The self-heating starting temperature of lithium iron phosphate is 144.7℃, and the starting temperature of thermal runaway is 205.4℃, which is the most difficult for thermal runaway to occur.
2. The maximum temperature of thermal runaway is 319.3℃, and the lowest thermal runaway calorific value per unit body weight is 185.1J/g, which corresponds to the smallest thermal hazard of the monomer thermal runaway, and the smaller the tendency of thermal runaway diffusion.
We can know that, when LiFePO4 battery thermal runaway, some changes will appear.
- Temperature change
- Voltage change
- Outlook change
Why we need to know thermal runaway of marine lithium battery?
- To protect equipment
- To protect environmentCharacteristics of thermal runaway flue gas of LFP battery
- To avoid horrible hazards
Dangers of lithium battery thermal runaway
- Cause the danger of fire or explosion
If batteries experience thermal runaway, there is a chance that they could catch fire. Firefighters need to be aware that batteries are a potential fire hazard because lithium ion batteries can produce high heat, smoke and ash.
-Cause the danger of human health
If the battery catches fire, toxic fumes can be released into the surrounding environment and can be inhaled by people, posing a risk to their health.
- Pollute surrounding environment
If the battery catches fire, it can lead to toxic fumes being released into the air. These fumes can be harmful to the surrounding environment.
Factors of lithium battery thermal runaway
· HEAT ABUSE
Thermal abuse does not occur spontaneously inside the battery. Often due to mechanical abuse and other reasons, the internal temperature of the battery rises to the threshold value, and the lithium battery will be heated locally, leading to thermal abuse, which further induces temperature out of control and causes the battery to spontaneously ignite.
· ELECTRICTY ABUSE
What we said electricity abuse is that we wrongly give our lithium marine battery electricity such as Over-charging, Over-discharging and giving mismatched chargers.
Is lithium battery very dangerous?
No. The damage which the thermal runaway of the battery caused will be devastating. However, you do not need to over nervous. Lithium batteries are widely used in vehicles, medical equipment, and other communicated machines. In new energy cars, 60% of fire accidents are caused by the thermal runaway of the battery itself, 30% are charging accidents, and only about 3.6% are due to the impact in driving accidents. Yes, these numbers are horrible, but the fire rate is very very low, in 2020, it is 0.18 per ten thousand. With the vigorous development of lithium batteries in all walks of life, people pay more attention to the safety of lithium batteries. Nowadays, although lithium batteries still have some dangerous factors, they do not affect personal safety.
How to protect marine lithium battery from thermal runaway in theory?
* To optimize the stability of the cathode material
· Set up a safety valve
· Install a thermistor
· Improve the film-forming quality of SEI
· Increase the melting point of the diaphragm
* To use solid electrolytes instead of liquid electrolytes
* To use composite collector instead of traditional collector
How to protect marine lithium battery from thermal runaway in daily life?
* keep your marine lithium battery in non-water environment
* Do not wrongly connect positive and negative connectors
* Keep your marine lithium battery in a room-temperature place
* Do not put your marine lithium battery with flammable substances
* Follow instructions to charge your lithium marine battery
* Choose marine lithium battery which match your equipment
* Match your marine battery with good BMS
