Corrosion resistance of electrolyte: Analysis of modified magnesium hydroxide cable sheath technology
In the fields of new energy vehicles, energy storage systems, and electric tools, cables, as the core power transmission components, are operating in increasingly complex environments. Especially in battery compartments or high-voltage modules, cables are exposed to harsh conditions such as high temperature, high humidity, and electrolyte leakage for a long time, which are highly susceptible to corrosion and aging, leading to a decrease in insulation performance and even causing safety accidents.
In order to improve the stability and safety of cables in these harsh environments, more and more companies are paying attention to the research and development of new sheath materials. Among them, the "modified magnesium hydroxide cable sheath technology" has gradually become the focus of industry attention due to its excellent corrosion resistance, flame retardancy, and environmental protection characteristics.
1、 Why does cable sheath face the risk of electrolyte corrosion?
The cable sheath is an important protective structure wrapped around the outer layer of the conductor, and its main functions include:
·Provide electrical insulation;
·Block external moisture and dust;
·Resist mechanical wear and chemical erosion.
However, in the power battery system of new energy vehicles, cables are often closely arranged with battery modules. Once electrolyte leakage occurs, if the sheath material does not have sufficient corrosion resistance, it may be quickly corroded, resulting in softening, cracking, and even carbonization.
The commonly used cable sheath materials, such as polyvinyl chloride (PVC) and polyolefin, exhibit varying degrees of degradation when in long-term contact with electrolytes. Therefore, it is imperative to develop new sheath materials with electrolyte corrosion resistance properties.
2、 Basic characteristics and limitations of magnesium hydroxide
Magnesium hydroxide, as an inorganic flame retardant, has been widely used in cable materials, especially in the field of fire prevention. It has the following advantages:
·High decomposition temperature, suitable for various processing techniques;
·During the combustion process, water vapor is released to absorb heat and cool down;
·Does not contain halogens, the products after combustion are non-toxic and harmless, in line with environmental trends.
However, there are significant shortcomings in directly using ordinary magnesium hydroxide:
·Poor dispersibility in polymer matrix, prone to agglomeration;
·Insufficient compatibility with organic materials, affecting processing performance;
·It is difficult to meet the corrosion resistance requirements of the electrolyte when used alone.
To overcome these problems, the industry has proposed a technical path of "modified magnesium hydroxide", which improves its comprehensive performance through surface treatment, composite modification, and other methods.
3、 Preparation and Performance Optimization of Modified Magnesium Hydroxide
The so-called "modification" refers to the surface modification of magnesium hydroxide particles through physical or chemical means to improve their dispersibility and interfacial adhesion in polymer systems. Common modification methods include:
1. Surface coating treatment
The surface of magnesium hydroxide is coated with silane coupling agents and titanate esters to enhance its adhesion with rubber or plastic substrates, thereby improving the overall density and stability of the material.
2. Micro processing
Control the particle size of magnesium hydroxide particles at the sub micron level, increase the specific surface area, and distribute them more evenly in the cable sheath material, reducing local defects.
3. Composite collaborative formula
In addition to using magnesium hydroxide alone, it can also be compounded with other functional additives, such as adding a small amount of nano alumina or zinc borate, to further enhance its dual properties of corrosion resistance and flame retardancy.
After the above modification treatment, magnesium hydroxide not only retains its original flame retardant advantages, but also exhibits stronger resistance to electrolyte corrosion.
4、 Application Practice of Modified Magnesium Hydroxide in Cable Sheath
In actual production, modified magnesium hydroxide is usually added to cable sheath materials such as silicone rubber, fluororubber, or cross-linked polyethylene (XLPE), used to manufacture key components such as high-voltage cables, battery connection wires, and charging interface protective covers for new energy vehicles.
The following is a practical case of a cable manufacturer adopting this technology in a high-voltage wiring harness project for new energy vehicles:
1. Material configuration plan
·Substrate: mainly silicone rubber;
·Modified magnesium hydroxide addition amount: 60-80 parts;
·Auxiliary fillers: a small amount of nano alumina and antioxidants;
·Processing method: Twin screw blending+extrusion molding.
2. Performance test results
The samples were subjected to a two-week electrolyte immersion test in a simulated battery compartment environment, and their flame retardant, electrical, and mechanical performance changes were evaluated simultaneously
·Appearance condition: No obvious swelling, whitening or cracking observed;
·Tensile strength retention rate: over 90%;
·Volume resistivity: maintained above 10 ¹⁴Ω· cm;
·Vertical combustion level: reaching UL94 V-0 level;
·Extreme oxygen index: increased to over 32%.
From the test data, it can be seen that the introduction of modified magnesium hydroxide significantly improves the stability and safety performance of cable sheath materials in electrolyte environments.
With the continuous expansion of the new energy industry, the requirements for cable sheath materials are also constantly increasing. In addition to being resistant to electrolyte corrosion, it is also necessary to consider multiple functions such as oil resistance, weather resistance, low smoke and non toxicity. In the future, the development direction of modified magnesium hydroxide technology may include:
·More refined surface modification process;
·Combining with biobased materials and biodegradable polymers;
·Integration of intelligent responsive flame retardant system.
In addition, customized modified magnesium hydroxide products will gradually enter the market for different application scenarios, such as in car fast charging systems and use in low-temperature and extremely cold regions.
As an indispensable part of new energy equipment, the performance of the sheath material of cables directly affects the safety and lifespan of the entire system. Faced with the practical challenge of electrolyte corrosion, modified magnesium hydroxide is becoming one of the key technologies to solve this problem due to its excellent chemical stability, environmental characteristics, and engineering adaptability.
From laboratory research to industrial implementation, this technology has demonstrated vast potential for application. For enterprises committed to improving product quality and safety standards, mastering and applying modified magnesium hydroxide sheath technology is undoubtedly a technology path worth exploring in depth.
If you have any requirements for material selection, formula design, or testing verification, please feel free to further communicate and cooperate.