Addvolt Since the EIC Accelerator: Reefer Batteries, Then Carrier

A refrigerated truck usually carries two diesel engines: one that drives it and a smaller one that runs the cooling unit, even when the truck is parked at a supermarket loading dock. Addvolt, founded in Porto in 2014 by four electrical engineers from the University of Porto, sells a battery pack that replaces the second one. In the EIC Accelerator pilot's October 2019 cut-off it won a grant-only award for ADDPLUGIN, a project to take that system to market, with an EU contribution of €1,687,864.50 towards a total cost of €2,411,235, according to CORDIS and the EU's transport research database TRIMIS.

Six years later the company no longer stands alone. Carrier Global Corporation, the American owner of the refrigeration maker Carrier Transicold, completed its acquisition of Addvolt on 2 May 2025, according to Carrier's announcement and Cooling Post. The price was not disclosed.

Where Addvolt Stands Now

Addvolt, S.A. still exists as a company. Iberinform, the Portuguese business-information arm of Atradius, lists it as active, with 26 to 50 employees and turnover between €2 million and €10 million, and the register summary on Racius shows a change to its articles and new board members in May 2025, the month of the takeover, and further board changes in January 2026. Its website still sells four product lines, from a 5 kW system for vans to 19 kW units for trucks and trailers.

Inside Carrier, Addvolt's technology now turns up under Carrier names. In January 2026 the logistics group HAVI put its first two Carrier Transicold Vector eCool trailer units into service in Portugal; the units were developed by Carrier Transicold with Addvolt and SAF-Holland, and HAVI Portugal's operations director credited "our partners Addvolt and Carrier Transicold", according to refindustry. In April 2026 Carrier announced [R]eCool, a plug-in battery retrofit that converts existing diesel Vector trailer units to hybrid or fully electric running and that "leverages Addvolt's advanced power electronic technology", according to Carrier Transicold.

The Technology: Braking Energy for the Cold Box

Transport refrigeration units on trucks and trailers are normally driven by their own small diesel engine, which keeps running while the vehicle stands still and is loud enough that some cities restrict night deliveries. Addvolt's system is a battery pack with power electronics that is fitted next to the existing refrigeration unit without rebuilding the vehicle. It recovers energy when the truck brakes or slows down, stores it, and can also be charged from the grid while the vehicle is parked, then powers the cooling unit and other auxiliaries such as tail lifts, according to the ADDPLUGIN report. A cloud platform, My Addvolt, tracks energy use and battery levels.

The selling point against the established alternative, a diesel-driven unit, is that it works on any truck: diesel, gas, hybrid, hydrogen or fully electric. On battery-electric trucks the system draws from the vehicle's own battery so the cooling does not need a diesel engine at all. The company claims "direct cost savings of 87-100% in fuel expenditure and an equivalent reduction in the CO2 emissions", which CORDIS records as "demonstrated in real use cases". No independent measurement of that range was found.

The nearest public numbers from a customer come from Aviludo, a Lisbon food distributor in the METRO group. In December 2024 it put two 7.5-tonne electric Maxus trucks with Frigicoll refrigeration and Addvolt Power Units on the road; each runs its cooling for about seven hours a day and ends the day with 30% of its range left, and the company reported a saving of 1,125 kg of CO2 a month, according to Grande Consumo.

What ADDPLUGIN Promised, and What CORDIS Shows

The European Commission's list of companies selected in the 9 October 2019 cut-off names "AddVolt, S.A." of Porto for ADDPLUGIN, grant only, with no partner company. CORDIS files the project under the Horizon 2020 SME instrument phase 2 funding scheme; it ran from 1 March 2020 to 31 October 2022 and is closed. The objective was to commercialise "the World's First Plug-in Electric system" for refrigerated vans, trucks, trailers and containers, aimed at the 1.1 million refrigerated trucks on Europe's roads.

The final periodic report, covering March 2021 to October 2022, says units were installed in partners' vehicles, validated in different operating regimes and "extreme environmental conditions" such as high humidity and low temperatures, extended to hybrid trucks, and that the My Addvolt platform was updated. It says that by the end of the project the company had adapted the technology to different regions, worked on its sales and market expansion model, and completed "demo applications in EU countries and US". It also explored a second-life use of its batteries as a mobile emergency charger for electric vehicles; no such product has been announced.

1. Commercial plug-in system for refrigerated vehiclesDeliveredSold to fleets such as Aviludo; built into Carrier's Vector eCool, per refindustry.
2. Validation across vehicle types and climatesDeliveredReported on CORDIS; pilots on hydrogen trucks in Switzerland and plug-in hybrids in Belgium, per ECO.
3. Market expansion across EuropeDelivered11 countries by December 2022, per ECO; the website now claims more than 20 markets.
4. Demonstrations in the USDeliveredReported on CORDIS; a US pilot was under way in December 2022, per ECO. No US customer has been announced.

The 87% to 100% fuel saving is a company figure, not a project milestone, and is treated as a claim here. Measured against the grant, the record is good: the system was already certified to the ECE-R10 vehicle standard and shown at the IAA trade fair in 2018, before the project began, according to Portugal Ventures, it was selling to fleets in several countries when the project ended, and the main commercial milestone the project pointed to, a large partner to sell through, arrived while it was still running. The US is the weak spot. In December 2022 Addvolt said a pilot was preparing a US market entry for 2023, according to ECO; in October 2023 the target had become 2024, according to TTR Data, citing Jornal de Negócios. No US launch has been announced since.

What Addvolt Achieved After the Award

The decisive relationship was with Carrier. In March 2021, a year into ADDPLUGIN, Carrier Transicold announced an agreement to use Addvolt's battery system in Europe, including in its new all-electric Vector eCool trailer unit; Carrier's Victor Calvo called it "an important step toward widespread commercial adoption of electric trailer refrigeration systems across Europe", according to FleetOwner. On 18 February 2022 Carrier launched a venture capital arm, Carrier Ventures, with Addvolt as one of its first two investments, according to ESG Today; the amount was not disclosed. The register summary on Racius shows a capital increase in February 2022.

Before that, the company was financed by Portuguese venture investors: a seed investment from 2bpartner in 2014 and a 2017 round from Abacus Alpha and Portugal Ventures, according to Portugal Ventures. Addvolt won a COTEC innovation prize in November 2022, according to ECO, and a Portugal Ventures award in December 2023, according to CMU Portugal. It is also a partner in two projects of Portugal's Recovery and Resilience Plan, NGS New Generation Storage and the Route 25 mobility agenda, with €1.62 million of approved funding, of which €950,062 had been paid, according to the Portal da Transparência. CORDIS also names Addvolt on the advisory board of MAGCCINE, an EIC Pathfinder project on magnetic refrigeration for vaccines, in which it receives no funding.

Addvolt's filed accounts are behind paywalls in the Portuguese registers. Two sources give 2023 figures: TTR Data lists revenue of €8.94 million, EBITDA of €1.63 million and 46 employees, and The Portugal News wrote that with "just fifty" employees the company had more than €8 million of revenue in 2023 and "strong profits". In December 2022 the company had told ECO it was aiming for €10 million of revenue in 2022; whether it reached that is not public. Iberinform marks the company's turnover trend as falling in its latest data, without giving figures.

The Exit

Carrier said about 60 Addvolt employees would join its Climate Solutions Transportation segment and that the deal would bring "advanced electrification technology, integrated power management and power electronics capabilities", according to Truck and Bus Builder. White Peak Partners advised Addvolt. Carrier's reports for the second and third quarters of 2025, filed with the SEC, do not name Addvolt, so the price is not public. The EIC Fund never held a stake: Addvolt's award was grant only, and the company does not appear in the EIC Fund's list of invested companies. One investor's result is public: Portugal Ventures' 2025 annual report singles out its exit from Addvolt at a multiple of 5.5 times its investment, according to the report.

Why It Matters for Europe

Heavy-duty vehicles cause more than a quarter of road transport greenhouse gas emissions in the EU and over 6% of total EU emissions, and the revised EU rules require manufacturers to cut the average CO2 emissions of new heavy-duty vehicles by 45% by 2030, 65% by 2035 and 90% by 2040, with separate cuts for new trailers from 2030, according to the European Commission. Diesel-driven cooling units are one of the remaining combustion engines in urban deliveries, and Addvolt's system lets fleets drop them without changing the truck.

The ownership question cuts the other way. A Portuguese firm that the EU and Portuguese public investors helped fund is now part of an American group. Its staff joined Carrier and the company keeps its registered address near Porto, and its technology is being sold more widely through Carrier's network than it could have been alone, but the intellectual property and future decisions now sit with Carrier.

The Verdict

Addvolt and Carrier have not been asked for comment for this article. It is based entirely on public records, company statements and EU project data, linked throughout.