The Structure of KECO Fire Prevention Chargers and Technical Reflections

Concept and Policy Background of Fire Prevention Chargers

Between 2022 and 2024, electric vehicle fire incidents were repeatedly reported through the media. Fires in underground parking lots, in particular, emerged as major social issues. At the time, some accidents were handled ambiguously with causes like "battery internal abnormalities" or "heat generation during charging," and both the causes and responses remained unclear, leading to a gradual accumulation of public anxiety. Against this social backdrop, the Ministry of Environment (KECO) launched a policy initiative called "Fire Prevention Chargers."

This initiative can be understood as part of a strategy to restore trust in electric vehicles and respond to safety risks, rather than simply expanding charging infrastructure. By adding battery condition diagnosis and charging control functions to the chargers themselves, the system was designed to technically monitor and control potential risk factors that could occur during charging.

Fire prevention chargers aim to prevent fires during electric vehicle charging. To achieve this, KECO is expanding PLC (Power Line Communication)-based slow chargers through a distribution program.

This article examines the technical implementation methods, effectiveness, and structural appropriateness of this policy from a personal perspective, based on practical experience in developing fire prevention chargers. It does not include the system establishment process or the perspective of policy beneficiaries.

If there are any incorrect interpretations or overlooked points, I will learn from and reflect feedback.

Note: The planning and execution of policies inevitably reflect complex factors such as technical feasibility, institutional constraints, and industry demands. This article is not an analysis that considers all such multifaceted structures, but rather a technical interpretation based on public documents and media reports about KECO's fire prevention charger policy. The author is not an expert in the relevant policy field, and the interpretations and judgments described in this article are personal views based on practical experience and limited information.

Technical Structure and Implementation Methods

Electric vehicle chargers are generally classified into fast chargers and slow chargers based on power level. This classification also affects the communication method between the charger and vehicle. Fast chargers typically use HLC (High-Level Communication), while slow chargers commonly use BS (Basic Signalling).

Note: In the industry, the term 'PLC' is sometimes used to refer to HLC as a whole, but strictly speaking, PLC is a physical layer communication method, and HLC is a logical layer that includes ISO15118-based session control and data exchange protocols operating on top of it. To avoid confusion, this article uses 'HLC' as the unified term.

HLC is based on the ISO15118 standard and provides bidirectional communication that can exchange various information such as the vehicle's battery state (SOC), user authentication, and charging schedule between the charger and vehicle. This capability provides the foundation for chargers to actively control charging.

In contrast, BS follows the IEC61851 standard, where the charger sends PWM (Pulse Width Modulation) signals and the vehicle provides feedback through resistance values in a unidirectional signaling system. This method operates on analog signals, making it structurally difficult to collect the vehicle's battery status or charging information in real-time without separate communication devices.

According to materials distributed by the Ministry of Environment, the core function of "Fire Prevention Chargers" is to prevent overcharging and recharging. However, to prevent overcharging, it must be possible to grasp the vehicle's SOC information in real-time, and in existing slow charger environments that only support BS, obtaining such information is impossible.

In other words, this initiative aims to lower fire risks by additionally introducing ISO15118-based HLC functionality to the slow charger environment, thereby obtaining the vehicle's battery status in real-time and controlling charging interruption or output based on that information.

• Overcharging
  • A state where current is supplied beyond the recommended voltage of battery cells, which can cause physical damage such as internal temperature rise, electrolyte decomposition, and cell expansion.
  • BMS generally prevents this through cell-level voltage monitoring and current cutoff logic, and overcharging only materializes when BMS malfunctions, sensor errors, or bypass charging paths occur.
• Recharging
  • A phenomenon where charging repeatedly resumes in response to slight voltage drops or residual current after the battery reaches a voltage close to 100% charge.
  • This can mainly occur with aging BMS or charging algorithms operating without simple hysteresis.

Implementation Status and Technical Challenges

"Fire Prevention Chargers" aim to reduce the risk of overcharging by having the charger receive the vehicle's battery status information and control charging accordingly. In this process, fire prevention chargers receive detailed battery information such as SoC (State of Charge), cell voltage, and module temperature from the vehicle.

This approach has clear significance as a technical attempt to strengthen the safety of the EV charging ecosystem while enabling advanced HLC-based control functions even in slow charger environments. However, in terms of practical operating environment and technical structure, it accompanies the following challenges and limitations.

Operational Challenges: Introduction Costs and Compatibility Issues

• Cost increase due to PLC modem introduction
  • To introduce HLC functionality into slow chargers, PLC modems must be additionally installed inside the chargers. This leads to increased hardware BOM (Bill of Materials) costs, which can raise the slow charger unit price by approximately 10-20%. In a price-sensitive slow charger market structure, this cost increase can act as a real constraint on distribution expansion from both supplier and consumer perspectives.
• Interoperability limitations of domestic-only VAS implementation
  • The "Fire Prevention Chargers" currently being distributed in Korea collect vehicle battery information using VAS (Value Added Services) functionality within the ISO15118 standard. However, this VAS functionality only defines the message transmission format, while the data content and meaning to be transmitted must be separately defined by the implementing entity. The domestic implementation designed its own VAS message format and interpretation system using this structure, making separate implementation essential not only for chargers but also on the vehicle side.
  • Particularly for overseas vehicle manufacturers, there is very little incentive to implement proprietary VAS messages solely for the Korean market. In fact, no vehicles currently on the market have been confirmed to support this functionality, and the practical application scope is very limited. As a result, there is a possibility that part of domestic charging infrastructure may become entrenched in specifications disconnected from international technology trends.
• Diffusion delays and structural costs
  • The latest revision, ISO15118-20 (2022), structurally supports the exchange of battery SoC information even in slow charging environments. If this standard had been applied, the same objective could have been achieved without designing separate data formats, and operational burdens such as technical complexity, certification procedures, documentation, and test system construction could have been reduced.
  • Conversely, implementing proprietary VAS functionality as currently done requires establishing separate certification systems for interoperability testing between chargers and vehicles, which works unfavorably in terms of both market propagation speed and ecosystem scalability.

Note: Cost increase estimates are unofficial figures based on interviews with domestic charger hardware manufacturers.

Structural Limitations

Charging Control Structure

Charging control for electric vehicles should ideally be centered on the vehicle's BMS (Battery Management System) as the most natural and stable structure. Charging limits, cell protection, temperature detection, etc., are all closely integrated with the vehicle's internal protection logic and include context that is difficult for external systems to judge.

Of course, complementary control functions for safety enhancement can exist in chargers, but when this function becomes too prominent, it entails the following structural problems:

• Mismatch between setting entity and control entity
  • When a user sets a charging limit in the vehicle but the charger stops charging based on external judgment, it becomes difficult for users to identify why charging is not occurring. This is not just a UX issue but can cause operational confusion.
• Overlapping and unclear responsibility
  • When charging failures or malfunctions occur, it is difficult to clearly identify whether the cause lies with the vehicle manufacturer, charger manufacturer, or operator (CPO). Complex responsibility boundaries can negatively affect not only complaint and failure response but also policy credibility.

Note: Vehicles (BMS) can control charging on their own. Even if chargers present the maximum supply current through PWM signals according to the IEC61851 standard, the actual current to accept is determined by the vehicle's BMS. Most electric vehicles terminate charging on their own by blocking or reducing current acceptance when the battery SoC reaches its upper limit.

However, the following problems can occur in real-world environments:

• If the BMS design or condition is imperfect, it may not accurately block current acceptance
• Recharging may occur repeatedly due to errors in cell balancing or charger logic

For these reasons, introducing auxiliary control logic on the charger side can contribute to preventing overcharging and recharging. However, this auxiliary control should not precede or become primary to vehicle control, and should only perform its role as a complementary means by design.

Information Management and Legal/Operational Risks

For battery information to be transmitted from the vehicle to the charger side, charger manufacturers and CPOs must bear legal and operational burdens beyond simple technical implementation.

• Information exposure and privacy invasion possibilities
  • Cell voltage, temperature, battery abnormality detection status, etc., are technical information closely linked to manufacturers' internal diagnostic logic. When this information is combined with metadata such as vehicle identification (VIN), user accounts, charging time and location, simple technical data transforms into personal information and becomes subject to legal interpretation.
  • During transmission to external systems such as chargers, servers, and cloud providers, storage, retention, and processing entities become distributed, which can become subject to privacy invasion, technical information leakage, and regulations such as the Personal Information Protection Act or GDPR.
• Legal notice/consent and liability dispute possibilities
  • If users do not explicitly consent to the collection and transmission of such information, risks such as notification duty violations, information misuse, and liability disputes in case of accidents follow. When incidents such as battery defects or fires occur in the future, the very fact that this information is recorded externally can become the cause of legal battles between manufacturers and operators.
• Increased operational and customer support burden
  • Charger manufacturers and operators must determine VAS support status and be able to interpret customer complaints by integrating vehicle logs and charger logs. This requires a more complex system than before in all areas of failure response, technical support, and documentation.

Policy Effectiveness and Future Direction

Policy Starting Point and Technical Significance

The "Fire Prevention Charger" policy appears to have originated from an intention to increase charging infrastructure safety and induce advancement. Fire prevention chargers can technically operate as complementary means, and can be evaluated as a legitimate attempt from the perspective of the public interest goal of safety. Furthermore, beyond simple distribution projects, it contains opportunities to elevate the technical level of charging infrastructure overall by one level.

However, vehicle charging status and battery protection are fundamentally areas that should be managed by the vehicle's internal BMS (Battery Management System). It would be architecturally more natural and reliable for chargers to remain in an auxiliary position for protection logic. Designs that attempt to judge and control charging status from outside increase structural complexity and can cause ambiguity in responsibility and operational confusion in case of charging failures.

Ultimately, while enhanced charger functionality has room to contribute to fire prevention, fundamental safety improvements are more likely to be achieved through vehicle system-centered improvements. Therefore, to evaluate policy effectiveness, it is necessary to verify how the technical structure of the control entity actually affects overall system stability.

Additionally, empirical review of fire prevention effects is needed. Clear indicators and analysis should be established to determine whether there have been changes in the frequency of fire accidents during charging before and after policy introduction, and whether the functionality has actually contributed to preventing fires. If fire accidents during charging were already on a gradual declining trend before the introduction of fire prevention chargers, it is necessary to distinguish whether this trend is due to vehicle technological advancement or improvements in manufacturer protection logic, or whether policy effects have materialized.

Charging Infrastructure Ecosystem Transformation and Preparation

The current domestic VAS utilization may have been a temporary solution. However, in the long term, effectively accommodating international standards such as ISO15118-20 and establishing universal interfaces between vehicle manufacturers and charging infrastructure operators would be a sustainable and maintainable structure.

ISO15118 is likely to establish itself as the foundational technology for not only fire prevention purposes but also advanced charging functions such as PnC (Plug and Charge) and V2G (Vehicle to Grid) that will be distributed in the future. Accordingly, policy direction also needs to not remain limited to short-term control function implementation, but comprehensively consider consistency with international technology trends, implementation feasibility, and ecosystem acceptability.

If the changes triggered by this policy can lead to a pioneering role in strengthening the technical capabilities of the charger manufacturing ecosystem and expanding infrastructure that accommodates international standards, then despite initial institutional confusion, it could become the starting point for positive technological evolution.