Innovative solutions for all battery-related issues

Ludwigsburg, May 22, 2023 – In Germany, e-mobility is in the fast lane: according to the Kraftfahrt-Bundesamt (German Federal Motor Transport Authority), nearly one in five newly registered passenger cars in the first quarter of 2023 was equipped with an electric drive, with more than 70 percent of them powered exclusively by electricity. Recent projections estimate that by 2030, more than 100 million electric vehicles could be on the road worldwide. Following the establishment of electric drive in the passenger car sector, heavy commercial vehicles and the first off-road applications are now increasingly entering the market. At the Battery Show Europe 2023, the Ludwigsburg-based filtration specialist MANN+HUMMEL is showcasing an expanded product portfolio centered around the heart of e-mobility, the battery (hall 4, booth D27).

In addition to pioneering innovations, the company also presents "expanded concepts, such as new variants of the VentPlus system," says Jürgen Kosicki, Manager Engineering Venting Units at MANN+HUMMEL. "With the modular VentPlus construction kit, a tailor-made pressure equalization element can be put together from tried-and-tested components to meet individual customer requirements. New designs, for example, offer various fastening options on the battery housing in addition to the internal screw connection commonly used today."

An important focus of MANN+HUMMEL's exhibition appearance is the so-called "Flying Cap" concept, which has "already been implemented in individual customer-specific cases, but has not yet been explicitly advertised," says Kosicki. The aim is to optimize battery safety: "In the event of a battery failure, large quantities of gas often escape, which can easily explode if a battery fire occurs. The energy density of today's cells is significantly higher than it was just a few years ago, and that also means more gas. A battery with several hundred cells must therefore be appropriately safeguarded."

Gas escaping from the cells must be discharged to the outside as quickly as possible. This is achieved by a membrane bursting or a lid flying off. "In principle, this works like a champagne cork," Kosicki explains. "When a certain pressure level is reached, it comes off all by itself purely mechanically; there's no need for sensor technology." What sounds simple in principle presented the developers with a real challenge, mainly in finding a balance between the release procedure and battery tightness. Kosicki: "A battery must remain absolutely watertight under all normal conditions over a service life of about fifteen years. On the other hand, there is the issue of safety with the question of at what pressure the release should occur."

Besides gas from failing cells, moisture is a major enemy of any battery. The newly developed Active Battery Venting Sorber by MANN+HUMMEL can reduce the risk of moisture inside the battery. "Through the pressure equalization membrane, moisture from the air penetrates into the battery," explains Jürgen Kosicki. "The whole thing can be compared to an outdoor jacket, which does not allow water to penetrate but wicks body moisture away to the outside." In modern high-voltage batteries, even the slightest moisture can cause voltage flashovers, he says. Moisture that has penetrated the battery must therefore be bound, for example by means of desiccants. One problem, however, is that in areas with very high humidity, the lifespan of the desiccant cartridges used is limited, he said. "The idea was to reactivate the granules inside again and again through a system. Thus, a smaller cartridge that is actively dried on a regular basis is sufficient. In order not to place an additional load on the vehicle battery, this is done about every three months during a quick charge. This results in a maintenance cycle of around two years, even under the most adverse conditions."