Which one is safer, ternary lithium-ion battery or LiFePO4 battery?

The full name of ternary lithium-ion battery is "ternary polymer lithium-ion battery", refers to the lithium-ion battery which anode material using nickel cobalt manganese acid lithium. It is named according to the "positive pole material". In addition to this, there are cobalt acid lithium, manganese acid lithium, lithium iron phosphate batteries. In addition to this way, we can also classify it according to the shape, the outsourcing material, electrolyte, etc.

The ternary lithium, manganese acid lithium, lithium iron phosphate can be used in electric vehicle. Say so many "lithium", you may be a bit dizzy, but today is the ternary lithium battery and lithium iron phosphate batteries.

Ternary lithium battery and lithium iron phosphate batteries themselves different characteristics, main contradiction focus on "energy density" and "security”. The ternary lithium battery energy density is bigger, but security is often suspect. lithium iron phosphate battery energy density is small, but you say that it is safer.

Differences of so-called "security", it is mainly due to anode material.

These two kinds of material will decompose when reaches a certain temperature, the ternary lithium materials will decompose at 200 degrees. And chemical reaction of the ternary lithium materials more intense, can release oxygen, under the effect of high temperature electrolyte rapid combustion, a chain reaction. And lithium iron phosphate can decompose during 700-700 degrees, not like a ternary lithium material release oxygen, burning less intense. Say simply, it is the ternary lithium material than lithium iron phosphate material easier to catch fire. Note that we mentioned here is "material".

From the point of a general trend, domestic automakers passenger car to use ternary lithium battery, including Beijing, BYD, jianghuai, etc. Corresponding suppliers are accelerating the ternary lithium battery production, such as lithium billion weft can revealed in its annual report in half, second phase of plant will mainly produce the ternary lithium battery.

As for the lithium iron phosphate batteries, more and more active in electric passenger car market. Last November, lithium iron phosphate battery electric bus installed capacity up to 64.9%, the ternary lithium battery installed capacity is only 27.6%. On the contrary, in the pure electric passenger car market, the ternary lithium battery installed capacity of more than 76% in November last year.

The problem is not what kind of batteries

We mentioned earlier, only three-yuan lithium and lithium iron phosphate material characteristic differences of the materials. And finally decided to security, is the whole Power battery System.

Due to the characteristics of lithium batteries, so there must be BMS (Battery Management System). (OVP) main functions including overcharge protection, discharge protection (UVP), over temperature protection (OTP), the over-current protection (OCP) composition among, and other functions, in the event of an accident, can immediately cut off the current.

If the battery pyrolysis, ask BMS is qualified.

So just think ternary lithium battery is unsafe, it is not very suitable. Ternary lithium materials easily pyrolysis, but not on behalf of the ternary lithium battery safety; lithium iron phosphate material pyrolysis not easily, but do not represent the lithium iron phosphate battery is safe.

The safety of the power battery is a system problem, not just the cause of the material. From the point of the pure electric passenger car spontaneous combustion accident of before, there are three-yuan lithium-ion batteries, also have lithium iron phosphate batteries. But the accident does not make a cell is failure, involves too many factors, fuel car spontaneous combustion is countless.

In fact, we should focus on is how to prevent the failure battery monomer harm other monomers, restricted by technological level, impossible to keep all the battery monomer consistency in 100%.

Zhenhua, general manager of new energy Li Shujun in recent GNEV conference is considered, the use of high energy density materials, the choice of face off firecrackers or grenades. Therefore, pragmatic approach is to focus on security module, and it is the focus of the failure isolation and safety protection. Monomer failure is inevitable phenomenon, but it can be controlled by monomer, to prevent module failure.

And macro view, if you are using the ternary lithium battery is in order to obtain higher range, so it can also have many other ways, such as the car lightweight and so on, this is a systemic project.

However, if the limits from policy three-yuan lithium-ion batteries, if these related electric vehicle technology faces "ignored"?

Anyhow, the choice of cell type, is to match the product positioning and technology. If because the bus mass casualties occur easily, prohibit ternary lithium batteries used on the bus, the car?

Dark a little thought, whether there is "the state protects the selfishness? If you limit the ternary lithium batteries used in commercial vehicles, that is probably the biggest beneficiary of the domestic lithium iron phosphate battery production enterprises, because South Korea main ternary lithium batteries and battery enterprises taking low line. However, this "protection" really promotes the development of domestic electric vehicles and related technologies?

In fact, the technology can solve the material inherent defects, and through policy to intervene in the development of technology is worth thinking about.

There is an option in an automotive engineers WeChat group that: an electric car catches fire isn't a bad thing, even it is better to happen earlier than later. The crux of the problem is not to use which kind of batteries, but is our electric cars increase too fast, leading to a large number of low-quality products, these are the real security risk.

The page contains the contents of the machine translation.