Kathmandu- Despite being a global leader in electric vehicles and batteries, BYD has repeatedly criticized battery types that differ from its own, particularly NMC (Nickel Manganese Cobalt) batteries. It isn’t limited to Nepal, similar claims have been made in India and Australia.

In Nepal, BYD operates through its distributor Cimex Inc. Pvt. Ltd., which is closely linked to BYD Auto Industries. Competing EV batteries, especially NMC ones, have been targeted with unverified safety concerns, despite there being no certified testing labs or qualified technical bodies in Nepal to support such claims.

BYD promotes its Blade Battery as safer, often comparing it to NMC batteries. However, both use entirely different chemistries—Blade uses LFP (Lithium Iron Phosphate), like other LFP batteries on the market. Its main difference is in packaging, not core materials. Comparing it to NMC batteries is misleading.


Difference between LFP and NMC battery  
First of all, let’s understand what LFP and NMC batteries are. Both are types of lithium batteries, but the difference lies in the materials used inside them, which affects their efficiency and performance.

LFP (Lithium Iron Phosphate)

 

LFP battery is made by mixing different elements. It generally contains 43percent cathode, 31percent anode, 20percent electrolyte, 4percent cell container, and 2percent separator. The cathode is the positive part of the battery that plays a key role in its performance. It helps increase energy storage, improve charging and discharging speed, and reduce risks. In LFP batteries, the cathode is mainly made up of 61percent phosphate, 35percent iron, and 4percent lithium.

 

In contrast, an NMC (Nickel Manganese Cobalt) battery uses a mix of nickel, manganese, and cobalt in its cathode. Nickel increases energy storage, manganese helps with power output and thermal stability, and cobalt improves the battery’s life and structure. Different versions of NMC batteries use different ratios of these three elements. For example, NMC 111 has equal parts of all three. In NMC 532, the nickel content is 50percent, while in NMC 622 and 811, it rises to 60percent and 80percent respectively. The more nickel there is, the higher the energy density of the battery.

Because LFP and NMC batteries have completely different chemistries, comparing them through a nail penetration test is not practical or accurate.

 

In Nepal, BYD’s official distributor, Cimex Inc., carried out such a test without any technical verification or approval from independent experts or certified labs.

Experts question the validity of BYD’s safety claims. In interviews with Biznessnews, six engineers from different technical fields described BYD’s well-publicized nail penetration test as an 'alleged test,' lacking regulatory approval or third-party validation. They noted that such tests in other countries follow strict rules, unlike the show put on in Nepal.

Opinion 1
When it comes to electric vehicle (EV) batteries, the focus should be on the fundamental chemistry rather than just the form or design. The key difference between battery types lies in their chemical composition—such as LFP (Lithium Iron Phosphate) and NMC (Nickel Manganese Cobalt)—not in their structure like 'Blade' vs. 'Conventional' formats.

Differences in the chemistry of LFP and NMC are: LFP batteries are known for being cheaper, longer-lasting, and safer, but they store less energy per kilogram, making them bulkier.

 

NMC batteries, on the other hand, offer higher energy density, better range, and stronger performance, but they are more expensive and degrade slightly faster due to the presence of nickel and cobalt.

The 'Blade Battery' is still based on LFP chemistry. Its innovation lies in the design—it arranges the cells in a compact, efficient way, improving packing density, heat dissipation, and structural integration into the vehicle chassis. However, this design does not overcome the inherent limitations of LFP chemistry. It still has lower energy density than NMC batteries and performs poorly in cold temperatures.

Therefore, comparing a Blade Battery to a regular NMC battery is not meaningful unless you’re looking at the chemistry behind them. A proper battery comparison should be based on metrics like energy density (how much energy per weight or volume), cycle life (how long it lasts), thermal stability (safety during overheating), charge rate (how fast it charges), and cold-weather performance (how it handles low temperatures).

Just comparing battery formats without considering these chemical and practical factors can be misleading. A better approach would be to compare LFP Blade batteries to conventional LFP batteries to see if the design actually improves performance, or compare LFP Blade to NMC module-based batteries to evaluate how chemistry affects real-world results. For instance, while Blade design might help with space efficiency and heat control, it doesn’t change the lower energy capacity of LFP.

 

That’s why companies like Tesla use NMC/NCA in their premium models, prioritizing range and energy over cost.

Conclusion: Marketing vs. Reality The real difference lies in the chemistry of the battery, not just its shape. While design can enhance performance within limits, it cannot change the core properties of the materials inside. So, to evaluate EV batteries fairly, we must compare chemistry and form separately—understanding that chemistry drives performance, and design helps optimize it.


 Opinion 2 

To understand the BYD Blade Battery, it’s important to first recognize that its core chemistry is Lithium Iron Phosphate (LFP), designed in a prismatic Cell-to-Pack (CTP) configuration. BYD manufactures its own batteries and has branded this configuration as the 'Blade Battery'—but fundamentally, it’s still an LFP battery. The term “Blade” is largely a marketing label, much like calling toothpaste Colgate or Pepsodent—while small design differences may exist, the underlying properties remain largely the same.

Other manufacturers like CATL and SAIC also produce similar LFP batteries in prismatic CTP format, such as those used in the MG S5, which are quite comparable to BYD’s Blade Battery.

Now to the main issue: is it valid to compare BYD’s LFP battery with an NMC (Nickel Manganese Cobalt) battery in a nail penetration test? The answer is a firm no.

 

Any meaningful comparison should be made between like-for-like systems—LFP to LFP—not between fundamentally different chemistries like LFP and NMC.

 

BYD’s nail penetration test presents an unrealistic scenario where a nail is shown piercing a battery, suggesting fire risk in one and safety in the other. But in reality, modern battery packs are engineered with multiple layers of protection, making it highly improbable—even for a bullet—to penetrate, let alone a simple nail. Additionally, these packs are equipped with cooling systems and safety mechanisms that significantly minimize fire risks under pressure or impact.

NMC batteries, while more expensive, offer their own advantages and are widely trusted by premium automakers like Tesla, BMW, Audi, Mercedes, and Porsche. These companies, many with over a century of automotive expertise (except Tesla), would not risk consumer safety by choosing unsafe battery technology. There is no evidence suggesting that NMC batteries used by these brands have higher fire incident rates than LFP.

So how can a relatively newer player like BYD conduct such unrealistic tests and use them to discredit NMC batteries? This approach appears more like a marketing gimmick than a valid safety demonstration. Moreover, there’s no clear third-party validation of these tests. How do we know whether the batteries tested were authentic NMC and LFP units? Without independent verification, these demonstrations raise more questions than they answer. 


Opinion 3 

NMC vs LFP Battery Safety: Nail Penetration Test Might Be Misleading

The EV industry is split between two battery chemistries: Nickel Manganese Cobalt (NMC) and Lithium Iron Phosphate (LFP). BYD has used dramatic nail penetration tests to highlight LFP’s safety. But does this test truly prove LFP’s superiority?

1. Fundamentals

Different Chemistry = Different Behavior
NMC and LFP batteries have different cathode materials, leading to distinct chemical and thermal reactions.

NMC: Higher energy density means more energy in less space, making it more reactive under extreme conditions, but it doesn’t imply a higher fire risk in normal use.
LFP: More thermally stable, but with lower energy density and worse performance in cold conditions.

 

2. The Nail Penetration Test: Marketing or Meaningful?

BYD’s Test: Limited and Misleading
The test shows LFP surviving without fire while NMC burns, but it’s a controlled test, not a full safety validation.

Real-World Scenarios Are Different
EVs have Battery Management Systems (BMS), thermal management, and protective packaging, which are not part of the nail penetration test. These features significantly reduce fire risk in real-world conditions.

System Design Matters More
Battery safety depends on overall system design, not just chemistry. The test doesn’t consider BMS or actual EV battery configurations.

3. Real-World Data: NMC Fires Are Rare

Low Incidence Rates
NMC fires are rare, with companies like Tesla and Hyundai having strong safety records. Fire incidents are exceptions.

Regulations and Certification
NMC batteries pass strict safety tests, ensuring only safe products reach the market.

4. What the Test Doesn’t Show

Battery Pack Engineering
The test isolates a cell, ignoring the protective packaging and thermal shielding used in real-world EV batteries, which prevent such incidents.

Vehicle Context Is Ignored
Battery safety depends on the full vehicle design. A well-designed NMC pack can be safer than an LFP pack in a poorly designed vehicle.

5. Trade-Offs Beyond Safety

Performance vs Stability

NMC: Offers better range, faster charging, and cold-weather performance, ideal for premium EVs.
LFP: Provides longer life and lower cost but sacrifices energy density, making it better for budget or urban EVs. In conclusion, while LFP is stable and cost-effective, NMC offers better performance. The nail penetration test is not a reliable measure of real-world battery safety.  

 Opinion 4   

 

What is the Nail Penetration Test?
The nail penetration test involves driving a metal nail through a battery cell to observe its reaction. LFP batteries generally remain stable with minimal fire risk, while NCM batteries may enter thermal runaway, potentially causing fire or smoke.

Why This Test Is Not a Fair Safety Measure?

Unrealistic in Real-World EV Scenarios: EV batteries are never exposed to direct nail penetration under normal use.

 

Ignores Other Safety Factors: This test focuses solely on thermal runaway from puncture and overlooks important factors such as Battery Management Systems (BMS), structural design, and protective layers.

 

Industry Safety Standards Do Not Require It: Global safety standards like UNECE R100, UL 2580, and SAE J2464 do not mandate a nail penetration test.

 

Supporting Evidence

UNECE R100 prioritizes crash, thermal, and electrical safety, not nail penetration.

Tesla's Model 3 and Model Y (NCM) have low fire rates due to advanced BMS and thermal management systems.

 

Issues with the Chevrolet Bolt EV (NCM) stemmed from manufacturing defects, not NCM instability, and were resolved after design improvements.

 

How BMS Ensures Safety in NCM Batteries?

BMS monitors voltage, temperature, and current to prevent overcharging and overheating, balances cells for even energy distribution, and activates thermal management systems to dissipate heat.

Real-World Evidence of BMS Effectiveness

A 2023 study by the National Fire Protection Association found that EVs have a lower fire risk per mile driven than gasoline vehicles, regardless of battery chemistry.
Tesla and other manufacturers use liquid cooling systems in NCM batteries, reducing thermal runaway risks.

The Rimac Nevera (NCM battery EV) passed rigorous UNECE crash tests, demonstrating that battery pack design and BMS matter more than raw chemistry.

 

Key Findings

A 2022 NHTSA report found EV battery fires are less common than gasoline car fires, regardless of battery chemistry.

 

A 2023 study by the Highway Loss Data Institute found that NCM EVs have fire rates similar to or lower than gasoline vehicles, thanks to improved safety engineering.

Tesla’s safety reports confirm that NCM-based vehicles have significantly lower fire risks per mile than internal combustion engine cars.

EV Battery Safety Tests Required by International Standards


Global safety standards focus on real-world tests, such as:

Crush Test: Simulates real-world crashes.

Overcharge Test: Tests the battery's ability to handle excess voltage.

Thermal Abuse Test: Assesses the battery's resistance to overheating.

External Fire Exposure Test: Evaluates how the battery reacts to external fire sources.

These tests are necessary for EV certification, while nail penetration is not required.

 

Case Study: Rimac Nevera (NCM) and UNECE Safety Testing

The Rimac Nevera (NCM EV) passed stringent UNECE crash testing without catastrophic failure, demonstrating that pack design and BMS are more critical to safety than battery chemistry.

Key Takeaways

Nail penetration is an unrealistic test and not a valid way to compare EV battery safety. Both LFP and NCM batteries are safe when properly designed with good BMS and thermal management. Global safety standards emphasize real-world tests, and crash data shows that modern NCM-based EVs have fire risks similar to LFP-based EVs.  

 

 

 

 

Conclusion: 

Cimex, BYD’s distributor in Nepal, has been promoting this so-called nail penetration test by using an NCM cell and claiming it represents NMC battery performance. This is outright dishonest. Even though NCM and NMC share the same chemical root, the current market standard is the NMC chemistry. Exploding a single cell and then claiming that the entire battery type is unsafe or catches fire easily is a serious technical misrepresentation—especially when done without trained professionals, certified labs, or any formal testing protocol.

In mid-2024, there were reports from China itself about BYD’s own Blade Battery—an LFP battery with special packing—catching fire. Similarly, just last week, a BYD Seal electric car caught fire in Thailand. That car was equipped with BYD’s Blade Battery. In contrast, there have been no recent reports of electric vehicles with NMC batteries catching fire.

Experts and engineers now clearly understand that while the composition of NMC batteries can potentially carry a higher fire risk, the solution is to use safer methods and systems in battery design. That’s precisely what manufacturers around the world using NMC chemistry are doing. Therefore, it appears that BYD Auto Industry Company Ltd. is leveraging weak regulations in Nepal to allow its distributor, Cimex Inc., to spread misleading information.

What’s even more important is that the battery pack, as used by BYD, is unlikely to face one-sided pressure as portrayed in their tests. Even if such abnormal pressure did occur, it wouldn’t cause the battery pack to explode like a box of gunpowder all at once. Under extreme stress, the battery would first emit smoke, and only later—through a chain reaction of misaligned chemical interactions—might it catch fire gradually.

In Nepal, however, Cimex misrepresented NMC batteries by using an NCM cell during the so-called nail penetration test.