This year, BYD and CATL launched relevant power battery safety solutions
based on the safety of new energy vehicles. According to recent news, Sunwanda’s
complete power battery solution that “only emits smoke and does not catch fire”
is about to be unveiled.
The experiment heated a battery core to cause thermal runaway and smoke.
The temperature of the surrounding battery cores increased but did not trigger
thermal runaway.
In fact, with the increase in the number, intensity of use, and service
life of new energy vehicles, safety accidents such as spontaneous combustion of
new energy vehicles have increased in the past two years, attracting attention
from all parties. In order to ensure the safety of personnel, at the policy
level, this year's new national standard for power batteries is aligned with the
United Nations global technical regulations, which requires that the thermal
diffusion time of the battery system be no less than 5 minutes, which is crucial
to improving safety and ensuring personnel escape.
Low temperature lithium iron phosphate battery 3.2V 20A -20℃ charging, -40℃
3C discharge capacity ≥70%
Charging temperature: -20~45℃ -Discharge temperature: -40~+55℃ -40℃ Support
maximum discharge rate: 3C -40℃ 3C discharge capacity retention rate ≥70%
Click for details
Fortunately, due to the mandatory requirements of the policy and the
technical efforts of battery companies, there have been no casualties in the
reported new energy vehicle safety accidents so far. However, it is worth noting
that most vehicles that spontaneously combust are eventually burned due to the
intensity of the fire, causing huge property losses and social impact.
Therefore, it is particularly important to ensure the safety of new energy
vehicles from ensuring personal safety (5 minutes escape time) to ensuring
personal and property safety (battery does not catch fire).
This also requires power batteries to have a higher level of safety to
eliminate consumers' potential concerns when purchasing and using them, and to
facilitate the large-scale promotion and application of new energy vehicles.
Analyzing the safety core of new energy vehicles, we can find that the
current main means and measures to deal with the safety risks of new energy
vehicles can be solved from three levels: the intrinsic safety of the battery
cells and the active safety and passive safety of the system.
The so-called intrinsic safety means that the battery core itself must be
safe, and the battery core is designed and manufactured, so the safety level
must be fundamentally improved from the perspective of design and
manufacturing.
Sunwanda's "only smoke, no fire" power battery solution chooses the nickel
5X ternary material system as the material system. It is reported that the
battery core uses single crystal, high-voltage medium nickel material. The heat
generation is at least 20% lower than that of polycrystalline ternary materials,
and the oxygen release temperature of the positive electrode is 30% higher. The
energy density is close to the current high-nickel system, and the material
safety is better. Advantage.
Unlike intrinsic safety, which relies on design and manufacturing, active
safety requires control, such as using battery management systems, big data
monitoring, intelligent early warning, etc. to control the safe use boundaries
of batteries and detect and prevent safety risks early.
For example, in terms of battery thermal management, based on the physical
and chemical characteristics of the battery, if the safety boundaries such as
temperature/voltage/current can be accurately controlled, the battery can be
ensured to work in a safe and comfortable zone. At the same time, the monitoring
model can be improved to identify safety risks immediately and Timely
warning.
According to Sunwanda, its BMS development process fully complies with
automotive electronic process requirements, and all core devices and BMS systems
meet functional safety ASILD level requirements; at the same time, Sunwanda has
also developed a set of high-precision SOX algorithms, full life cycle SOC The
estimation accuracy is less than 3%. In addition, the BMS can also accurately
diagnose the battery cells in advance, provide early warning of thermal runaway,
and predict potential dangers of the battery to prevent safety accidents.
In terms of passive safety, it is mainly through mechanical safety design.
Even if the vehicle is involved in an accident, the battery system will not be
damaged, or once the battery thermal runaway occurs, how to prevent it from
causing a spontaneous combustion accident requires technical and engineering
design of the battery and the entire vehicle. Design in multiple dimensions.
In addition to the control strategies for active safety and passive safety
of system products, Sunwanda also proposed cloud security on the battery
application side, comprehensively evaluate and monitor battery health status and
safety, and ensure battery safety through big data and mechanism models. safe
operation.
According to Battery China.com, only a few companies such as CATL, BYD, and
Sunwanda have mass-produced "smoke-only, no fire" batteries, and some domestic
companies plan to launch battery solutions that have no heat spread and no fire.
Judging from the "smoke only, no fire" power battery technology trends launched
by various companies, there are some common trends worthy of attention:
First, the ternary material system is still the focus and mainstream of
industrial research.
Because the energy density of ternary battery materials is higher, it can
meet the needs of new energy vehicles for longer battery life and better
discharge rates. In order to meet consumers' needs for vehicle battery life and
the vehicle's intelligent and strong power consumption needs, the entire vehicle
must be placed in a limited space. Increasing the charge capacity is still the
main direction. CATL, Sunwoda and others have proposed "only smoke, no fire"
battery packs based on ternary battery materials, indicating that the industry
has extended the safety boundary of ternary batteries and improved the safety of
ternary batteries. Regarding the safety of battery use, the safety disadvantages
of ternary batteries compared to lithium iron phosphate will gradually shrink in
the future. The advantages of ternary batteries in energy density will still
make them continue to become mainstream.
Second, the application scale of single crystal nickel ternary material
system will expand rapidly.
The non-flammable batteries launched by industry companies such as Sunwanda
are based on monocrystalline high-voltage nickel 5X materials. It can be seen
that the high-voltage single crystal material represented by the "5 series",
namely "5X", has outstanding material-level thermal stability on the premise of
close to the "811" energy density, which greatly improves safety.
At the same time, both in terms of material manufacturing and battery cell
manufacturing, Nickel 5X also has an advantage in cost compared to 811. It is
expected that driven by well-known OEMs and leading battery companies, the
5-series monocrystalline high voltage will be used in the future. There will be
significant growth in material applications. Battery China Network
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