Tesla Shares Details of Its Upcoming Wireless Charger [VIDEO]

Tesla has confirmed that its upcoming wireless charging intended for the Robotaxi is “well above 90%” efficient. While wireless charging for smartphones tends to be about 70-75% efficient in general, a lot of the inefficiency comes from heat and alignment issues.

Tesla appears to have tackled both of these key problems to make wireless charging efficient enough for electric vehicles. Let’s take a look at how, but before we do that, let’s take a look at SAE J2954, the wireless EV charging standard from nearly half a decade ago.

SAE’s wireless charging standard was created in October 2020. Engineers from SAE and car manufacturers collaborated to build a standard that would work across all EVs. In the end, they figured out a grid-to-battery efficiency of up to 94%. The NACS connector itself is only slightly more efficient—98.55% or so, depending on the temperature of the connector, the cable, the battery pack, and the transformer. That sets a benchmark for what Tesla aims to meet with its wireless charging standard.

What were their key challenges for efficiency? Heat and alignment.

Tesla’s Autopark will receive special support for its wireless chargers. Autopark will automatically locate the wireless charging pad and park the vehicle in the best spot for the charging session to begin. As long as the vehicle can accurately place itself over the wireless charger, this solves one of the key issues with wireless charging. It’s not clear whether Tesla is building in any other technology to help the charger find its optimal position. In theory, magnets, like the newer Qi2 standard or Apple’s MagSafe, can help the charger lock in millimeter-perfect positioning.

Having the vehicle locate and park itself over the charger will be far easier than humans trying to accomplish the same feat without software assistance.

A major problem with cell phones and wireless charging is that most do not have active heat dissipation. Instead, they dissipate heat passively into the atmosphere around them. This is especially true due to the small surface area of a cell phone.

In a car, you can transfer heat efficiently to outside the vehicle or into the vehicle’s cabin if it needs heat - the heat pumps on a Tesla are 200-300% efficient at most temperatures. Conversely, on cell phones, battery heat must be limited due to the critical and heat-sensitive components (screen, chips, cameras, sensors) that are all tightly packed into the phone’s battery.

Due to Tesla’s BMS (battery management system), Tesla can keep the vehicle’s batteries and surrounding components in a much more ideal range than cell phones. The system will not only cool down batteries, but also warm them up to produce efficiency and faster charging.

Robotaxi wireless charging No hands required pic.twitter.com/XL746DkGhb

The final trick under the charge mat is beam steering. In a recent patent, Tesla explained that they intend to steer the beam of wireless energy by altering the induced current across the wireless charging pad’s coils. This will allow them to solve both the alignment and heat issues.

The alignment's precision can be achieved by steering the beam into the optimal position, while it dynamically adjusts between 'cool zones' on the receiving vehicle to prevent overheating—ensuring a steady and efficient rate of charging.

Tesla has thought out the wireless charging problem pretty deeply ever since they bought out Wiferion, and this achievement has been years in the making. We’re hoping they’ll eventually bring wireless charging compatibility to the rest of the lineup. The Cybertruck itself already has the connector prongs to be retrofitted with a wireless charging adapter, and with the Model Y Juniper Refresh around the corner, what better way to prove wireless EV charging works than to include it in the world’s best-selling car?

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