Chinese battery manufacturer CALB is overhauling its quality and safety systems following widespread swelling and other failures involving lithium iron phosphate (LFP) battery cells used in GAC Aion vehicles.
The Hong Kong-listed battery maker has introduced changes covering manufacturing tolerances, process traceability, validation procedures, organisational responsibilities and customer quality management, according to a report by Chinese media outlet Auto Time.
The measures follow incidents involving 177-Ah LFP cells supplied by CALB for Aion S vehicles, with some batteries reportedly developing problems after between 150,000 and 300,000 kilometres of operation.
CALB Tightens Manufacturing Standards
CALB has tightened controls over electrode production, including thickness measurements and areal-density management during the coating process.
According to people familiar with the changes cited by Auto Time, the company is bringing these controls in line with specifications used by CATL.
The company previously operated within an industry-standard areal-density deviation range of about 2.3 to 2.5 g/cm³ for LFP cathodes. Under the revised system, the deviation is required to remain within ±1.5%.
CALB has also upgraded online monitoring of dew points and moisture levels during electrolyte filling. The company has strengthened sample traceability as well, moving from daily retained-batch records to tracking individual production rolls.
The battery maker is also reviewing historical production inputs. It is conducting a retrospective audit of incoming materials, auxiliary materials and additive formulations used on production lines during 2022 and 2023, while discontinuing some formulations considered to have insufficient safety margins.
Quality Department Gains Greater Authority
CALB has revised design standards for battery casings, explosion-proof valves and welding margins around terminal posts as part of efforts to improve durability and provide additional safety redundancy.
The company has also established a dedicated rapid-response customer quality team within its passenger vehicle division. It is working with major customers to jointly monitor battery management system data in an effort to identify potential issues earlier.
One of the most significant organisational changes gives CALB’s quality department veto authority over battery batch releases.
“As long as a batch fails to meet the quality department’s review standards, even research and development teams rushing to meet project deadlines cannot bypass the approval process,” a person familiar with the matter was quoted as saying.
The change is intended to prevent production schedules or urgent automaker requirements from overriding quality approval procedures.
Aion Battery Controversy Drives Changes
The quality overhaul follows a series of reported battery problems in GAC Aion vehicles equipped with CALB’s 177-Ah LFP cells.
Some Aion S vehicles experienced cell swelling, electrolyte leakage and sudden power loss after accumulating between 150,000 and 300,000 kilometres. The issue became known as the “banana battery” controversy because some swollen cells reportedly deformed into a curved shape.
Vehicles using the affected cells recorded sales of about 220,900 units in 2023, with approximately 72% sold into ride-hailing and taxi fleets, according to Auto Time.
GAC Aion announced on July 18 that it would extend the battery warranty for affected models to eight years or 300,000 kilometres. The company also said it would provide free inspections and replacements.
CALB established a direct maintenance channel for affected customers and said it would assume ultimate responsibility for the quality of its battery cells.
Quality Overhaul Adds Cost Pressure
The measures are expected to increase CALB’s near-term costs as the company funds after-sales compensation, upgrades production standards and restructures its quality and manufacturing processes.
The financial impact comes as CALB continues to expand its battery business. First-quarter revenue increased 71.2% year on year to 11.8 billion yuan ($1.74 billion), while domestic battery installations reached 7.31 GWh, giving the company a 5.86% share of the Chinese market during the period.
CALB installed 5.2 GWh of batteries in China in June alone, representing a 6.82% market share, according to China Automotive Battery Innovation Alliance data.
Source: CnEVPost
