Sensata Technologies’ power disconnect solution for DC fast charging
By Chad Elmore08 July 2021
New product is latest in series of DC fast charging announcements by Sensata.
Sensata Technologies, a technology company and provider of sensor-rich solutions, said its new power disconnect solution has been chosen by several leading charging infrastructure OEMs to enable faster and safer DC fast charging. Sensata said its solution combines contactors and GigaFuses from its Gigavac brand to provide a value-added contactor module, simplifying customers’ installations while delivering safer and more effective system protection compared to traditional contactor and thermal fuse pairings.
To compete with traditional internal combustion engines, electric vehicles need faster charging times, so charging systems are quickly migrating from 400 V to 1000 V and from 50 kW to up to 350 kW to shorten charging times to less than 20 minutes, said the company. While higher voltage and current levels reduce charging times, they increase the safety risks and design challenges for the systems. High voltage contactors provide safe circuit continuity while fuses are required in tandem for circuit-protection in the event of a hazardous short circuit event.
The increases in voltage and current levels not only require contactors with higher breaking capabilities, but also make the contactor and fuse pairings more technically challenging. To address these challenges, Sensata said DC fast charging infrastructure OEMs are seeking safer, higher performing and more comprehensive solutions that improve on the traditional contactor and thermal fuse pairing.
The company said its GigaFuse offers several advantages compared to a conventional DC thermal fuse, including the ability to:
- Open a circuit within 3 mS
- Open a circuit closer to normal operating conditions without nuisance tripping, resulting in less potential risk of damage
- Pair more easily with the contactor because of its electro-mechanical triggering mechanism
- Help prevent overloading, improving the performance of the contactor in the circuit
- Reduce thermal resistance; typically, 0.15 mohm
- Eliminate thermal aging due to low heat generation
The packaged power disconnect module includes high voltage contactors and GigaFuses that are harnessed to a mounting plate. The company said the solution delivers overcurrent and short circuit protection.
“Our recent wins with major charging infrastructure OEMs demonstrate the additional value we provide to our customers as we move from being a component supplier to a leading electrification solutions provider,” said Nick Moelders, vice president, Electrification at Sensata Technologies. “Working engineer-to-engineer with the most innovative companies allows us to learn and adapt to the needs of the rapidly transforming clean energy market.”
PDU business notes
The new product is the latest in a number of recent announcements Sensata has made in the DC fast charging space. In April, it said it had secured a contract with a “leading truck OEM” to provide its Power Distribution Units (PDUs) for DC fast charging of electric trucks. The total value of the award is $15 million across a five-year period.
The PDUs are optimized for heavy vehicle electrified powertrains operating up to 850 V and use contactor, fuse and control unit technologies from its Gigavac and Lithium Balance brands in addition to a compact, actively cooled design to enable 500 A (and higher) for charging.
The manufacturer of electric long-haul trucks needed a solution to provide safe and reliable control and protection for DC fast charging of its next generation truck. Sensata said a solution was critical to electric vehicle safety and equipment lifetime – protecting the vehicle operator as well as the batteries. The PDU safely disconnects power from the battery system in the event of a short circuit, which can occur from a variety of scenarios such as a vehicle being hit by another while charging, or a defect in the charging cable.
To ensure electrical safety while charging the vehicle, Sensata said it is critical that the high voltage contactor and fuse be paired properly for fault coverage in all operating conditions. To solve this challenge, Sensata’s PDU used GigaFuse technology with pyrotechnic capabilities to provide fast triggering in the event of a short-circuit, paired with the appropriate Gigavac contactor. In addition to the fuse and switch technology from Sensata’s Gigavac brand; it also uses Lithium Balance’s controller technology with embedded software capabilities for high voltage inter-lock (HVIL), contactor control and communication of current, temperature and voltage.
“We expect the global electric commercial vehicle market to grow at a CAGR of 20% from 2020 to 2030,” said Moelders, “and the acquisition of battery management system capabilities in combination with our contactors enables us to provide this new solution which opens a serviceable available market (SAM) upwards of $1.3B for Sensata across all types of PDUs in electric trucks and buses.
“This strategic win demonstrates the success of our combined technology portfolios from recent acquisitions like Gigavac and Lithium Balance and how this allows us to provide more comprehensive solutions to our customers as they commit to electrifying their fleets.”
The company said there are inherent challenges to the design of this type of solution, especially when it comes to current levels, temperature, space constraints and cyber security. Components must meet current carry and temperature requirements by incorporating a cooling system into the design. Sensata’s teams in electrical and mechanical engineering and software development worked with the customer to develop a comprehensive solution. Utilizing the experience in controls and technological know-how from Lithium Balance, they developed a custom control board for use in electrification applications.
Sensata purchased California-based Gigavac in 2018 and, earlier this year, acquired a majority of Lithium Balance. The latter company was founded in 2006 as aprovider of battery management systems and is based in Denmark.