Introduction
With the rise of renewable energies and storage solutions, Cables for energy storage systems occupy an essential place in the energy transition. These cables ensure the safe and efficient transmission of electricity between batteries, inverters and other system equipment. It is important to clarify that cables for energy storage systems do not store electricity themselves. They play a crucial role in the connection and reliability of the entire installation.
In an energy storage system (ESS), the choice of cable directly influences performance and safety. An incorrectly sized cable can cause significant electrical losses, overheating, or even fire risks. Conversely, a quality, well-adapted cable guarantees optimal performance, better battery durability and installation that complies with safety standards.
Faced with the diversity of options available – battery cables, solar cables (PV), flexible cables or XLPE power cables – it becomes essential to understand the selection criteria. This article guides you step by step to choose the most suitable cable for your energy storage system, while respecting technical requirements and international standards.
Why cable choice is essential ?
In an energy storage system, cables for energy storage systems are not just accessories : they determine the ability of the installation to operate safely and at full efficiency. Each project involves high and often continuous currents, especially during battery charge and discharge cycles. Undersized cables can cause significant voltage drop, reduce overall efficiency and accelerate component wear.
Another major issue is thermal management. Les batteries lithium-ion, For example, are sensitive to temperature variations. An unsuitable cable can heat up excessively, increasing the risk of failure or fire. What's more, certain environments – such as technical rooms, residential buildings or photovoltaic power plants – require specific cables, such as LSZH cables (low smoke and halogen free) to limit the risks in the event of fire, or shielded cables to protect against electromagnetic interference.
In summary, choosing your cables wisely is not just a question of compliance, but directly conditions security, energy efficiency and lifespan of the storage system.
Technical criteria for choosing a suitable cable
Conductor section and current capacity
The first criterion is the sizing of the cable. The conductor section must be chosen according to the maximum intensity that the system can deliver during charge and discharge cycles. A cable that is too thin leads to voltage drop and overheating, while a well-sized cable ensures efficient and secure transmission.
Example : for high capacity batteries, it is recommended to use battery cables with a large section.
Rated voltage and compatibility with batteries
Each cable is designed to withstand a precise voltage rating. In an energy storage system, it is essential to check the compatibility between the voltage of the batteries (often 48 V, 400 V or more) and cable characteristics.
Cables for solar batteries or inverters must comply with IEC/EN standards to avoid premature degradation.
Flexibility and ease of installation
In systems where space is limited, such as electrical cabinets or residential installations, cable flexibility plays an important role. Flexible battery cables make wiring easier, reduce installation time and improve connection reliability.
Insulation and protective sheath
Cable insulation guarantees electrical safety. For sensitive environments (hospitals, public buildings, indoor facilities), LSZH cables (Low Smoke Zero Halogen) are recommended : in the event of a fire, they limit the emission of smoke and toxic gases. In outdoor environments, a UV and moisture resistant jacket is essential to protect the durability of the cable.
Mechanical and electromagnetic protection
Certain industrial installations require cables reinforced against mechanical attack (abrasion, torsion) or against electromagnetic interference. In these cases, it is preferable to opt for shielded cables or high performance cables suitable for demanding environments.
The main types of cables for energy storage systems
Battery cables
Battery cables are specially designed to connect batteries to inverters or energy management systems. They are generally flexible to facilitate connections in small spaces, and equipped with thick insulation to withstand high direct currents. These cables are essential in residential and industrial systems where the reliability of the battery connection is crucial.
Solar cables (PV cables)
Solar cables or photovoltaic cables provide the connection between the solar panels and the storage system. They must withstand external conditions : UV, humidity, temperature variations. IEC standard 62930 defines their main characteristics. These cables are often used in addition to batteries to provide a reliable solar energy storage solution..
XLPE insulated power cables
For large capacity installations, particularly industrial or high voltage, XLPE cables are preferred (Insulation in reticulated polyethylene). They support high voltages, have excellent thermal and mechanical resistance, and guarantee stable transmission over long distances. These cables are part of the high-performance electrical cables used in large-scale energy storage systems.
Special LSZH cables (low smoke and halogen free)
In closed or sensitive environments, fire safety is a priority. LSZH cables are designed to limit smoke and toxic gas emissions in the event of a fire. They are found in public buildings, hospitals or data centers where energy storage systems must meet strict security requirements.
Standards and certifications to respect
The choice of cables for energy storage systems cannot be limited to technical characteristics alone : it must also meet strict safety and performance standards. These standards guarantee the reliability of the product and its compliance with international and local regulations..
International standards (IEC, IN, UL)
IEC (International Electrotechnical Commission) : defines global standards for electrical cables, like IEC standard 62930 for photovoltaic and IEC cables 60502 for power cables.
IN (European standards) : ensure cable compliance with electrical safety requirements in Europe.
UL (Underwriters Laboratories) : widely used for North American markets, they guarantee fire safety and the quality of materials.
French standards and certifications
NF (French Standard) : issued by AFNOR, it certifies that the cable meets safety requirements, performance and durability specific to the French market. For residential projects, tertiary or industrial in France, the use of NF certified cables is strongly recommended, or even required by certain principals.
Safety and environmental certifications
CE : mandatory for placing on the European market.
RoHS : limits the use of hazardous substances in the manufacture of cables.
LSZH (Low Smoke Zero Halogen) : required in certain environments to limit the emission of smoke and toxic gases in the event of fire.
Importance of certified cables
Opt for IEC certified cables, IN, NF or UL, This means ensuring a compliant installation, durable and secure. This not only protects the equipment (batteries, inverters), but also the users. For industrial and residential projects, a cable without certification can represent a major risk in the event of an audit, insurance or claims.
Practical advice for selection and installation
Check the cable section before purchasing
Always use sizing charts or battery manufacturer recommendations to choose the correct section. For example, a lithium battery of 48 V with a capacity of 200 Ah will require much thicker cables than a small residential system of 24 V.
Favor certified cables that comply with standards
Systematically opt for NF certified cables, CE or IEC. This not only guarantees security, but also facilitates administrative procedures (assurances, audits techniques). Standards-compliant energy storage system cables provide greater durability and long-term peace of mind.
Adapt the cable to the installation environment
Indoors : prefer LSZH cables, which limit smoke and toxic gases in the event of fire.
Outdoors : choose cables resistant to UV and humidity.
In an industrial environment : use shielded cables to avoid electromagnetic interference.
Take care of installation and connections
Even a high quality cable can become a weak point if installed incorrectly. Respect the bending radii indicated by the manufacturer, secure the cables correctly to avoid friction, and use terminals adapted to the section. Correct crimping is essential to avoid hot spots.
Provide a safety margin
Never dimension your cables “as accurately as possible”. Allow a safety margin of 10 has 20 % on current capacity, in order to compensate for load peaks or future developments in the system (adding batteries or inverters).
Conclusion
The choice of cables for energy storage systems directly affects the safety and performance of your installation. Focus on quality cables, adapted and certified, it guarantees optimal and sustainable operation. For any questions or project needs, do not hesitate to contact us. Our experts are at your disposal to support you and help you choose the cables best suited to your needs.