[ad_1]
GM has announced that it is recalling all Chevrolet Bolts made to date, including newer models of electric utility vehicles, over concerns that a manufacturing defect in batteries made by LG could cause a fire.
The Bolt was first recalled in November after five cars that had not been in accidents caught fire. After further investigating the issue, Chevrolet recalled a second batch in July. The problem was attributed to two manufacturing defects that could occur simultaneously. The defects – a torn anode tab and a bent separator – created conditions that could lead to a short in the affected cells. So far, the company has identified 10 fires involving faulty batteries, according to an AP report.
This third and final recall includes 73,000 bolts manufactured between 2019 and 2022, the current model year, and brings the total recall to nearly 142,000 cars, of which more than 100,000 have been sold in the United States. GM estimates the initial recalls will cost $ 800 million, and it expects the new one to add $ 1 billion in total. GM said it would ask LG for a refund.
To fix the problem, the automaker will replace the batteries in the vehicles, an expensive and time-consuming procedure that will take some time. Until replacement batteries are ready and service appointments can be scheduled, GM has recommended Bolt owners park their vehicles outside and limit their battery’s state of charge. at 90% or less. The company also recommended not to let the estimated range drop below 70 miles. GM says it is working with LG Chem to increase the production of replacement cells.
Tracing the problem
The faulty batteries were initially attributed to an LG Chem factory in Ochang, South Korea, and the companies believed the problem was limited to that factory. But a fire a few weeks ago in Chandler, Ariz. Involving a 2019 Bolt led investigators to broaden their scope, revealing problems were also present in batteries that had been made at other LG factories. .
GM and LG Chem are partners in a new multi-billion dollar joint venture to manufacture the Ultium batteries that will underpin a line of new electric vehicles from the Detroit automaker. The companies announced two $ 2.3 billion battery factories in Ohio and Tennessee, with the first scheduled to begin production next year.
GM initially partnered with LG Chem for its high-voltage batteries in 2008, when the automaker selected the company to supply packs for its Chevy Volt plug-in hybrid. At the time, it was widely believed that GM chose the Korean company because of its established track record in the relatively new field of lithium-ion batteries. This was probably the right choice given that one of the contract’s contenders, A123, suffered a black eye a few years later when its batteries were responsible for a string of rechargeable Fisker Karma hybrids made of bricks.
But even LG Chem’s experience and manufacturing prowess has not made it immune to high-stakes mistakes. “The batteries are tough,” Greg Less, technical director of the University of Michigan Battery Lab, told me for another article. “If they weren’t hard, everyone would make them.”
In recent years, battery manufacturers have struggled to balance competing needs for cost, stability and performance when developing new chemistries. Many lithium-ion batteries in cars use cobalt to maintain stability during charging and discharging. But cobalt is expensive, and most of it is in the Democratic Republic of the Congo, a country known for its uneven human rights record and substandard mining conditions. Electrochemists have been working to reduce the amount of cobalt used, exchanging it for nickel, which also has the benefit of increasing energy density. Unfortunately, batteries with a high nickel content are also more prone to fire.
Although neither GM nor LG have released details of the Bolt’s battery chemistry, its ingredients are said to be NMC 622, which is six parts nickel, two parts manganese, and two parts cobalt. It’s similar to what other car manufacturers use. There have been a lot of recalls recently as automakers resolve issues in their battery supply chains – Ford, Hyundai and BMW have all announced recalls recently. So far, these recalls are smaller than GM’s, and their causes range from manufacturing defects to potential software problems.
No more fires?
While electric vehicle fires grab the headlines, it’s unclear whether EVs ignite more frequently than vehicles with internal combustion engines. Earlier this month, Tesla released a figure in a report claiming fossil-fueled vehicles are 11 times more likely to catch on fire than Tesla’s own cars (measured by fires per billion kilometers driven). On the flip side, 2019 data from the London Fire Brigade suggests plug-in cars are more likely to catch on fire than ICE vehicles (0.1% vs. 0.04% of cars registered in the city).
As GM continues to invest in electrification, the company clearly understands that it must act quickly to rectify the problem. “We are working with our suppliers and manufacturing teams to determine the best way to speed up battery capacity for module replacement as part of the recall,” GM spokesperson Dan Flores wrote to CNBC at the following last month’s recall. “These teams are working tirelessly on this problem. “
[ad_2]
Source link