Recently, two more energy storage companies, namely Haichen Energy Storage and Canadian Solar, have "burned" their own products.

In June 2025, Haichen Energy Storage announced that its ∞Block 5MWh energy storage system successfully completed the world's first open-door extreme combustion test. This pioneering effort not only broke the boundaries of traditional safety testing, but also redefined the safety standards of energy storage systems with four extreme challenges.

On June 3, e-STORAGE announced that its SolBank 3.0 energy storage system has successfully passed the Large-Scale Fire Testing (LSFT).

The test is carried out in strict accordance with CSA C-800:25§9.7 Large-Scale Fire Testing (LSFT) standard.

Before the two companies, industry giants such as Sungrow, Huawei, and BYD have also verified the safety of their products through rigorous fire tests. A competition for energy storage technology with "safety" as its core is unfolding around the world.

Extreme Challenge: Haichen Energy Storage's Open-Door Combustion Test Breakthrough

In recent years, safety accidents caused by thermal runaway of energy storage systems have occurred frequently, making energy storage safety issues a hot topic. In this context, strict and standardized safety testing has become an urgent need for the development of the industry, and the open-door combustion test came into being.

The reason why Haichen Energy Storage's test attracted industry attention is that it set four extreme conditions that exceeded the current industry standards, pushing the energy storage system to the absolute limit of safety performance. The first challenge was the world's first open-door test in an "unrestrained combustion" environment - the cabinet door was open throughout the process, and oxygen was fully and freely circulated, forming an extreme environment where the fire and thermal runaway energy far exceeded the traditional closed-door test. Under such conditions of a surge in oxygen circulation, the combustion temperature can reach over 1300°C, and the system structure faces an unprecedented high temperature test.

The second challenge is: double 15cm limit spacing  -  no thermal runaway spread in the "close-range " system. The "back-to-back, shoulder-to-shoulder" cabinet spacing is compressed to the industry limit of 15cm. Facing flame temperatures above 1300°C, no heat spread occurs in adjacent cabinet systems, verifying the system's close-range thermal runaway isolation capability.

The third challenge is the shutdown of the active fire protection system  - "no external assistance" long-term fire resistance safety performance: completely shut down external fire protection intervention, and only rely on the energy storage system's own passive fire protection design to withstand the test of long-term fire, verifying the system's autonomous fire protection capability and high reliability without external fire protection intervention.

The fourth challenge is to test under full-power conditions to amplify the scale of thermal runaway energy release and verify the reliability and stability of the system design under the most stringent conditions.

The test was conducted under the full witness of the internationally recognized testing and certification organization UL, American certified fire engineers and customers. It strictly followed the UL9540A and NFPA855 test methods and conducted a combustion test based on the above four extreme challenges. The severity of the test increased exponentially.

After 15 hours of extreme combustion, the prefabricated cabin structure of Haichen Energy Storage 5MWh remained intact, and no heat spread occurred in the three adjacent boxes, breaking through the multiple extreme tests of "open door + extreme spacing + long-term combustion" , and fully verifying the system safety protection capabilities of Haichen Energy Storage's 20-foot ∞Block 5MWh system during extreme combustion. This also means that in real scenarios, even if there is a long-term fire attack, the energy storage system can still buy more time for emergency personnel to intervene and ensure personal and property safety.

Large-scale fire test by Canadian Solar

Test results from Canadian Solar ( e-STORAGE) show that SolBank 3.0 can effectively control thermal runaway events within a single battery cabinet, meet key fire safety standards, and provide a higher level of safety for the deployment of large-scale energy storage power station projects around the world.

This test is strictly in accordance with CSA C-800:25 §9.7 Large -Scale  Fire Testing ( LSFT) standard. This standard is recognized as a rigorous test specification in the industry and is specifically used to evaluate the ability to control the spread of fire to adjacent units when a complete combustion occurs inside a battery energy storage system ( BESS) unit cabinet.

During the test, all doors and structural components of the target unit remained closed and intact. This test standard meets the key safety requirements of NFPA 855 , including the ability to effectively prevent thermal runaway chain reactions and ensure that the fire is strictly contained within a single unit.

In this test, the SolBank 3.0 energy storage system of Canadian Solar ( e-STORAGE) demonstrated excellent fire protection performance. The test results show that SolBank 3.0 effectively prevented the fire from spreading to the target unit and successfully passed this rigorous test. This result verifies that the SolBank 3.0 passive fire protection design has excellent safety and reliability.

The test was conducted by the international testing agency CSA GroupIt was witnessed by the US energy storage safety agency Energy Safety Response Group ( ESRG  ) , which issued an independent verification report.

Energy storage safety concerns give rise to a wave of rigorous testing

The breakthrough tests of Haichen Energy Storage and Canadian Solar are not isolated incidents, but a concentrated reflection of the increasing attention paid to safety in the global energy storage industry in recent years.

According to statistics, there were at least 15 energy storage fire accidents in the world in 2024 alone, and 9 more safety accidents in the first quarter of 2025. These incidents not only caused significant economic losses, but also triggered a crisis of trust in energy storage technology. Against this backdrop, rigorous safety testing has become an important way to rebuild market confidence.

From a global perspective, at least six industry-leading companies have conducted various forms of energy storage fire experiments since 2024.

In June 2024, Sungrow proactively ignited a real PowerTitan1.0 machine, completing the first large-scale combustion test of an energy storage system certified by DNV as an "industry milestone"; in November of the same year, it invested approximately RMB 30 million to conduct the largest-scale and longest real-machine combustion test at the time on the 20MWh PowerTitan2.0.

Trina Energy Storage conducted a 24-hour combustion test on its Trinastorage Elementa King Kong 2 product , and created a unique "aerosol fire extinguishing + water sprinkler cooling" dual insurance system; BYD became the first company in China to pass the CSA TS-800 large-scale fire test , and its Magic Cube Energy Storage System achieved zero spread between cabinets, becoming the first company in China to pass this test.

In February 2025, Huawei Digital Energy completed the extreme combustion test of intelligent string grid-connected energy storage under the full witness of DNV and strategic customers. Based on the internationally accepted standard UL9540A test method, this test significantly increased the number of thermal runaway cells, and the test severity increased exponentially.

Companies are competing with each other to continuously break through the boundaries of security testing and jointly promote the improvement of the industry's security baseline.