Taking the pressure off batteries

Taking the pressure off batteries

Trelleborg is helping the automotive industry mitigate battery issues inherent in stop-start systems with a small but ingenious valve seal.

Stop-start vehicle systems are gaining popularity in the automotive industry for their role in increasing fuel economy and at the same time reducing environmental impact. The systems use a type of lead acid battery known as Absorbent Glass Mat (AGM), which incorporates a glass mat that absorbs and holds the acid while separating the positive and negative plates. This battery has many attributes, including long life and vibration resistance as well as being totally sealed and virtually spill-proof, maintenance-free and fully recyclable.

Start-stop vehicle technology puts a lot of strain on the battery because while the engine is off, the battery is the sole source of power to all the car’s electrical devices, such as the air conditioning, radio and navigation system. In advanced start-stop systems, which incorporate regenerative braking or passive boost, there is further stress to the battery.

A key to the proper function of AGM batteries is the ability to release pressure from minor gassing that occurs during charging. This can lead to explosive fumes and
degradation of battery performance. To deal effectively with this issue, Trelleborg Sealing Solutions has developed the Ventseal Light, a patented design that is a combined seal and pressure-controlled valve.

The valve deals with low pressure buildup and opens between pressures of 50 to 400 mbar, depending on the application. Once the pressure is released the device
closes automatically to prevent leakage from the battery. Although it is a tiny component compared with the size of the battery, this critical part must provide reliable sealing throughout the life of the battery and operate at extreme temperatures. “The valve allows for a high rate of charge and discharge, something that happens when the engine switches on and off to save on fuel consumption,” says Martin Hignett, Managing Director of Trelleborg Sealing Solutions in Malta.

Hignett continues: “With increased punitive legislation related to fuel consumption, stopstart systems have become more attractive, as they can save between 2 and 10 percent on fuel consumption. The penalties for carmakers failing to meet fuel economies have gone from annoying to painful!” Europe has been an enthusiastic adopter of start-stop, and both the United States and China are now starting to increase the use of this technology as well.

The Ventseal Light was originally developed to meet the technical needs of an AGM manufacturer and was introduced on the market in 2001, having gained a patent a
year earlier. Hignett says that since 2012, significant investments have been made to support the growth in demand for the Ventseal Light. Trelleborg in Malta is currently set to produce 160 million Ventseal parts annually. However, as the demand for AGM increases, so it is likely will the demand for the Ventseal.

The company prides itself on its in-house development capability, which includes the development of elastomer materials as well as process enhancements, made possible thanks to its highly automated production facility. The automation extends from injection molding to robotic punch finishing, inspection and packing.

Hignett sees a bright future for Ventseal Light, as AGM batteries have considerable growth potential for other types of demanding applications that range from
storing energy generated by solar panels and wind turbines to boats, aircraft, jet skis and mobility vehicles.

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This is an article has been reproduced from Trelleborg's T-Time magazine. To download the latest edition, go to: www.trelleborg.com/t-time 

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