Apple and BYD worked together around 2017 to develop a battery system using LFP cells, a technology designed to last longer and be safer than typical EV batteries at the time, according to Bloomberg.

Apple (NASDAQ: AAPL) secretly worked with BYD (HKG: 1211, OTCMKTS: BYDDY) to develop long-range power batteries before abandoning its car project earlier this year, according to a Bloomberg report today.

The iPhone maker and BYD teamed up around 2017 to develop a battery system using lithium iron phosphate (LFP) cells, a technology designed to last longer and be safer than typical electric vehicle (EV) batteries at the time, the report said, citing people familiar with the matter.

While Apple doesn't own any of the technology used in BYD's current blade batteries, the partnership demonstrates its efforts to produce cars, the report noted.

The technology Apple and BYD were developing together would be highly customized to fit the cars once planned. As part of the secret collaboration, Apple engineers brought expertise in advanced battery packs and thermal management, while BYD contributed manufacturing techniques and advancements using LFP cells, according to the report.

Spokespeople for Apple and BYD declined to comment on the joint battery work, Bloomberg said, adding that BYD said in an emailed statement that “the concept for the Blade battery originated with BYD engineers, who independently developed this LFP Blade battery. BYD holds complete property rights and patent rights for the Blade battery.”

Today, BYD's entire lineup of cars is powered by its signature blade battery system, which uses a battery pack design that people involved in its development say was informed by lessons from the Apple work, according to Bloomberg.

Apple canceled its decade-long EV manufacturing effort in late February, abandoning one of the most ambitious projects in the company's history.

In late March, BYD chairman and president Wang Chuanfu met with Apple CEO Tim Cook, who was visiting the city at the time, at Apple's China headquarters in Shanghai.

The seeds of Apple's partnership with BYD were planted about a decade ago, when the US company was looking for core technology for its cars, according to the Bloomberg report today.

BYD engineers showed Apple executives an early version of the bade battery, and they praised the technology's safety and energy-storage capabilities, the report said, adding that Apple ultimately sought customizations that could increase the range of an EV, people familiar with the matter said.

Apple had already been working on several different batteries at the time, using elements such as nickel and alkaline. It also invested millions of dollars in battery pack design and engineering to squeeze in as many cells as possible, according to the report.

The two companies sought to combine the separate pack and cell efforts to produce a safe, long-range battery system for the Apple vehicle, the report said.

Despite working with BYD for years, Apple eventually backed away from the partnership and considered using systems from other battery makers, Bloomberg said, citing people familiar with the matter.

The entire car project suffered multiple delays, and the economics of the EV business ultimately proved too daunting, the report noted.

Shenzhen-based BYD has become the world's largest new energy vehicle (NEV) maker and the world's second-largest maker of power batteries.

The company sold 3,024,417 NEVs, including plug-in hybrid electric vehicles (PHEVs) and battery electric vehicles (BEVs), in 2023, a year-on-year increase of 62.30 percent, according to data compiled by CnEVPost.

In the January-September period of this year, BYD's NEV sales amounted to 2,747,875 units, up 32.13 percent year-on-year.

The Chinese NEV maker saw its BEV sales overtake Tesla's in the fourth quarter of 2023 -- the only time so far. Tesla produces only BEVs.

In the third quarter, Tesla's global deliveries of 462,890 units continued to outpace BYD's BEV sales of 443,426 units.

The rapid growth of the NEV business has helped BYD's battery business rise quickly. The company's EV batteries are primarily used in its own vehicles, although models including Nio's (NYSE: NIO) Onvo L60 and Xpeng's (NYSE: XPEV) Mona M03 have also started using them.

In the January-August period, BYD was second in the global EV battery market with a 16.4 percent share, behind CATL's (SHE: 300750) 37.1 percent, according to South Korean market researcher SNE Research.