BEIJING, March 14 (Reuters) - Chinese electric vehicle

maker Nio on Thursday signed an agreement with battery

giant CATL on a partnership to develop batteries

with a longer life as part of efforts to lower overall EV costs.

The partnership will leverage battery technologies from each

company seeking to lower the so-called "full life circle" costs

of batteries, key for the operating costs of Nio's thousands of

battery swapping and charging stations, William Li, Nio's

founder and CEO, told reporters in Beijing.

Li said the goal was to extend battery usage beyond eight or

10 years.

Nio also announced a cut to monthly rental fees for

batteries by up to 33% for Nio users, which works to lower EV

purchase costs by as much as 128,000 yuan ($17,795.82).

After receiving more than $3 billion from Abu Dhabi investor

CYVN Holdings last year, Nio has strived to turn profitable

sooner by trimming its workforce and deferring long-term

investments to improve efficiency.

The company, however, said it would still keep investing in

developing core technologies such as batteries on its own. It

has commercialised 150 kilowatt hour (kWh) semi-solid-state

batteries for its EVs, manufactured by Beijing Welion New

Energy, which have a range of up to 1,000 km (620 miles).

Nio has also invested heavily in infrastructures for battery

charging and swapping. It currently has 2,382 battery swapping

stations and 21,652 public charging stations, according to Li,

adding that the charging has turned profitable for Nio while

it's still losing money for the battery swapping services.

Swapping could help to ease the strain on power grids at

peak times when drivers recharge, but industry analysts and

executives expect it would only become feasible if batteries

become more standardised.

While some have criticised battery swapping stations as a

costly investment, Nio argues they can be both a quicker

solution to powering up EVs and an energy storage facility to

improve grid stability.

Nio currently buys most of its batteries from CATL

and has been exploring battery supplies from new

partners such as CALB.

($1 = 7.1927 Chinese yuan renminbi)