A decade ago, when the electric vehicle revolution was only in its infancy, thermal management systems for early adopters were developed using an amalgamation of commercial off-the-shelf components referred to as “COTS.” These early adopting OEMs developed EVs and PHEVs (Plug in Electric Vehicles) with little focus on mastering integration, but rather choosing function and commodity cost as core tenants in the design. Early EV thermal systems relied heavily on existing low-voltage pumps, simple valves, basic plate heat-exchangers, and commodity Positive Temperature Coefficient (PTC) heaters for both cabin heating and for battery heating. As the demand for electric vehicles grew, large OEMs continued to rely on core “off-the-shelf” components to develop their thermal systems while some start-ups started to get creative with their solutions.
In late 2017, the Tesla Model 3 was introduced into the market with high expectations. Early reviews of the vehicle were poor because the build quality, fit and finish, and paint quality were not at the levels of traditional OEMs. In the spring of 2018, Sandy Munro of Munro & Associates, tore down a Model 3 and revealed Tesla’s approach to thermal systems. The “Super Bottle” was first discovered by Sandy and his team and they highlighted that the Model 3 had a massive amount of integration in the thermal system. The vehicle used the reservoir for the ethylene glycol as the heart of the system. The bottle had multiple provisions for mounting each of the two low-voltage pumps and the bottle integrated the ports for the multi-directional valve. The super bottle had mounting provisions for the direct-mounted chiller on the side of the bottle and the ethylene glycol level sensor was also integrated into the bottle. The “Super Bottle,” as named by Tesla Engineers on the neck of the bottle, was a beautiful example of what is possible if your design process forgoes the use of existing commercial components. The pumps and valves available through the supply base would not allow for the engineers at any organization to achieve the level of integration on display in the early Model 3 vehicle.
Why does a high level of integration matter? The answer: efficiency. Reducing the total amount of fluid in the thermal system allows for a reduction in weight and a reduction in pumping losses throughout the system. A reduction of up to 70% in thermal system lines was measured when comparing a Tesla Model 3 with other electric vehicles in its class. Each bend in a line, each connection point, and each liter of fluid drives an increase to pump sizing for the thermal system. The other ancillary benefits of this level of integration are the elimination of brackets and mount provisions for commercial components that need to be secured to the vehicle.
What else does the future hold for the automotive supply base? The Answer: 48 volts. At Tesla’s investor day in Austin, Texas, Elon Musk and his extended leadership team highlighted their path forward and the technology advancements needed to achieve their goals. Tesla released a detailed presentation covering new advancements in the assembly process of their vehicles, a new 48 volt architecture, and a lower cost solution for their electric drive units. The decision to switch the low voltage architecture from 12 volts to 48 volts has been a long debated topic among major OEM’s around the world. The wattage demands of vehicles has risen dramatically in the past two decades, necessitating larger wires to accommodate the current demands of these systems. In the past decade, some mild hybrids and PHEVs have employed 48 volt (and up to 100 volt) batteries to contribute to the powertrain in various configurations. Some of those hybrid vehicles would then utilize the hybrid battery to run high wattage systems, such as electric power steering and electric boosted brake systems. The 48 volt systems in these rare scenarios never extended beyond the high demand systems and 12 volt systems would remain on the rest of the vehicle. Tesla’s announcement of 48 volts is a major step change to whole vehicle electrical architecture. A 48 volt system will push the Tier 1, Tier 2, and even Tier 3 supplied motors, actuators, pumps, lights, switches, buttons and wiring to a completely new designs.
The accelerated shift to electrification will provide ample opportunity for suppliers to stake their claim on emerging technological solutions. Nothing is off limits, from thermal system integration to 48 volt low voltage architectures. Remaining agile is key as the automotive landscape pushes forward.
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