BMW uses molds, heat and pressure

BMWSet of 6 Cars: 5" BMW X5 SUV, Pull Back Action. uses molds, heat and pressure to produce contours in the fabric. Resin is then injected into the molds to bond the fibres together. How the resin flows through the fibres is crucial; it has to be done quickly and leave no area untreated before it starts to cure. A release agent in the resin migrates to the surface to prevent the component sticking in the mold. The whole process, which can be handled by robots, is completed in minutes.
The resulting carbon-fibre parts are bonded together to construct the body of the car. Besides their lightness, BMW's experimental vehicles have exceeded expectations in crash tests, says the company. During front- and rear-impact-tests the aluminium chassis crumples to absorb energy, but leaves the rigid carbon-fibre passenger compartment intact. Even extreme side-impacts protected the crash dummies and the battery (automatically switched off when the airbags trigger). In many cases crash damage is reparable by cutting out broken sections of carbon fibre and bonding in new ones.
At some poinSet of 6 Cars: 5" BMW X5 SUV, Pull Back Action.t, Set of 6 Cars: 5" BMW X5 SUV, Pull Back Action.however, carbon-fibre cars will be scrapped. Steel and aluminium is easy to recycle, but carbon fibre is tricky. Carmakers are working with aerospace firms on ways to do it. BMW has pioneered a process to reuse offcuts by breaking them up with heat to turn them back into raw material. This can be used to make composites with about half the strength of new carbon fibre.
Another advantage of a carbon-fibre body is that it will not corrode. So, apart from the battery wearing out in ten years or so, electric cars could last for decades (electric motors need little servicing). This will make it even harder for car designers to persuade those driving electrically to trade in their rustless, tough-as-old-boots vehicles for a new model.