The rapid advancement of energy storage systems in commercial and industrial applications has also brought a new layer of safety-related challenges. As demand grows and BESSs become more prevalent in factories, shopping malls, hospitals, and logistics centers, exposure to risks such as short circuits, insulation failures, thermal diffusion, and fires increases—events that have already caused large-scale accidents worldwide.
This scenario puts pressure on the sector to seek more robust engineering solutions, capable of increasing the reliability of systems and ensuring that the expansion of energy storage is accompanied by more rigorous technical standards.
Commercial and Industrial (C&I) energy storage systems are highly complex and therefore require a rigorous level of integration between their electrical and thermal components. Although battery cells have advanced considerably, it is noteworthy that the true safety of BESS (Battery Energy Storage System) today depends on the integration design of the system as a whole.
Conventional solutions still have significant gaps, especially in protection against short circuits and in containing thermal runaway, which are precisely the mechanisms that most often trigger accidents. These deficiencies make safety design one of the main challenges in the sector, affecting both operational reliability and the ability to prevent the escalation of failures.
O New C2C Dual Link Security White Paper Released by Huawei in partnership with TÜV Rheinland, this report presents an in-depth analysis of the growing risks in C&I energy storage systems and proposes a novel security architecture structured to address the main mechanisms that lead to failures, fires, and explosions in lithium batteries.
The document contextualizes the accelerated growth of the market, driven by the drop in the price of lithium carbonate, the maturity of PV+ESS models, and incentive policies. However, it warns that this progress is accompanied by a significant increase in accidents, especially in complex environments such as factories, shopping malls, hospitals, and university campuses.
The document highlights that more than three quarters of accidents reported globally since 2009, events have occurred in C&I systemsThese failures are typically linked to insulation faults, internal short circuits, or uncontrolled thermal diffusion. Analysis of the cases reveals a worrying pattern: many damaged systems... They complied with international standards.This highlights that current standards are still insufficient for scenarios with high population density and high property value.
Short circuits, as previously mentioned, are one of the main safety risks in energy storage systems, as they can spread rapidly and trigger a thermal runaway, causing severe damage to the system. They can be caused by various factors; Figure 1 shows the main causes of short circuits in energy storage systems.
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Figure 1: Causes of electrical short circuits in storage systems. Source: Huawei Security White Paper
Current Overview of Storage Systems
C&I energy storage systems are highly complex and depend on precise integration between their electrical and thermal components. Although cell technology has matured, the greatest safety risks today arise from flaws in integration design—especially in short-circuit protection and the ability to suppress or contain thermal runaway, as the Huawei document points out.
These two mechanisms are at the heart of the escalation of accidents, as an internal short circuit in a cell can rapidly trigger intense exothermic reactions, temperatures exceeding 1.000 °C, and the release of a large volume of combustible gases, creating conditions for fire or explosion in short periods.
Current conventional systems have significant shortcomings in detecting internal short circuits. Traditional data acquisition chips have low accuracy, a high margin of error, and insufficient speed, which limits their ability to identify abnormal cell parameters and issue early warnings.
Furthermore, incorrect cable connections, component failures such as IGBTs, and damage during transport or installation can cause different types of short circuits—between positive and negative busbars, between phases on the AC side, or even shorts to ground—increasing the risk of fire when there is no rapid disconnection of high current.
Another critical point highlighted by the document is the inadequate insulation design at the battery pack level. Conventional insulation focuses on the outer casing and neglects insulation between adjacent cells, modules, and the top cover, allowing the propagation of electrical and thermal faults.
The material used in these assemblies is also insufficient for high-temperature environments: leaked electrolytes corrode the insulation layer in a matter of days, and plastic casings can melt during thermal runaway, compromising the entire structure.
As a result, insulation faults become triggers for internal short circuits and large-scale system damage, requiring a complete redesign of traditional protection solutions to meet current safety requirements.
Figure 2 shows an example of cell assembly melting due to thermal runaway in conventional insulation systems.
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Figure 2: Melting of the cell assembly due to thermal runaway. Source: Huawei Security White Paper. C2C Architecture: Integrated electrical and thermal safety for BESS in Commerce and Industry (C&I)
In response to the scenario described in the previous topics, Huawei introduces the “C2C: From Cell to Consumer”, an innovative dual-link security architecture model (C2C), which rebuilds security from the cell level to the point of consumption, acting simultaneously on two fronts: electrical safety and thermal safety.
Figure 3 shows the DNA of the double-link security architecture. C2C From Huawei, which establishes complete protection at all layers of the system, starting at the individual cell, through the battery pack, and reaching the BESS operating level, creating a continuous security barrier from beginning to end.
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Figure 3: C2C dual-link security architecture. Source: Huawei Security White Paper. In the electrical connection, the system employs intelligent sensors, advanced cloud-based algorithms, and continuous monitoring to detect more than 13 types of cell faults, in addition to implementing reinforced six-sided insulation, insulating paint with 30 days of electrolytic resistance, and metal enclosures capable of maintaining integrity even at high temperatures.
A major security improvement is detected in five-level protectionThis protection, compared to three or at most four protections in traditional systems on the market, ensures safety at each stage of the system and consists of the application of a fuse in the battery pack, an enhanced contact at the rack level, an enhanced fuse at the rack level, no wave transmitted by the PCS IGBT, and an instantaneous PCS circuit breaker.
This is essential to prevent electrical faults, such as short circuits from the cell to ground, short circuits between the positive and negative busbars on the front and rear doors of the battery rack, short circuits within the PCS, and short circuits between phases on the AC side, achieving complete protection from the DC side to the AC side.
Figure 4 presents the five-level protection architecture of Huawei BESS.
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Figure 4: Five-layer protection of Huawei's BESS system. Source: Huawei Security White Paper. Furthermore, in the case of a short circuit from the cell to the high-current ground, which has a higher probability of catching fire, rapid disconnection can be achieved in as little as 5 ms, a major technical advantage that directly impacts fire prevention and the protection of people and assets.
Figure 5 presents the C2C electrical link security architecture discussed in this topic.
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Figure 5: C2C dual link security: electrical link security architecture. Source: Huawei Security White Paper. In the protection of the battery pack, high-resistance insulation materials are applied between the cells and at the points of contact with caps, plates, and assemblies, preventing short circuits caused by incorrect connections, electric arcs, and sparks that could reach the battery casing.
Figure 6 shows the six-sided insulation of the cells and battery packs performed on the BESS systems produced by Huawei.
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Figure 6: Six-sided insulation for the battery pack. Source: Huawei Security White Paper. Regarding thermal bonding, the equipment features innovative insulation materials with resistance >350 ºC and conductivity ≤0,1 W/(m·K), designed to prevent the propagation of thermal runaway between cells. The system also incorporates rapid liquid cooling and positive pressure oxygen blocking strategies, drastically reducing the risk of combustion or explosion.
Furthermore, Huawei designs the ESS enclosure to rapidly vent internal gases through a directed path, preventing the buildup that leads to structural explosion, one of the most critical elements found in recent accidents.
The design objective is to minimize the impacts of a potential thermal runaway event, ensuring that there is no thermal diffusion between cells, no fire in the pack, no explosion in the system, and no risk to the consumer.
Figure 7 shows the C2C thermal bonding safety architecture.
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Figure 7: C2C dual-link security: thermal link security architecture. Credit: Huawei Security White Paper. Final considerations: a new level of security for BESS C&I
In an industry that is growing faster than its normalization, Huawei's white paper positions itself as a benchmark guide to raise the security standard of BESS applications in Commerce and Industry (C&I), especially given the operational complexity and high risk involved in these environments.
The document not only identifies flaws and bottlenecks in current standards, but also presents concrete technical solutions, validated in rigorous tests developed in conjunction with TÜV Rheinland.
For companies, EPCs, integrators, and professionals in the field, this material represents a robust synthesis of the state of the art in storage security, while also highlighting why C2C architecture stands out as one of the most comprehensive approaches on the current market.
The opinions and information expressed are the sole responsibility of the author and do not necessarily represent the official position of the author. Canal Solar.
