Australian energy storage firm Redflow Limited has suspended delivery of its flow batteries while the company investigates potential performance issues.
The Queensland-based company said laboratory testing of electrolyte samples from one “specifically-identified batch of 10 batteries indicate that they may be at risk of failure due to the presence of impurities in battery electrolyte”.
Redflow said in an Australian Stock Exchange announcement on 24 April that samples from a further 20 batteries out of its Australian stock “have just been sent for laboratory testing”. Results are expected in early May.
“The results show impurities in the tested battery electrolyte exceed operating limits set by Redflow,” the company said. “These impurities were not present when the battery electrolyte was loaded into the batteries in the factory. The impurities may have arisen from a supply chain quality issue with a specific batch of source material used in the manufacture of the products tested.”
The company said it believes “the issue can be remedied economically” in any affected batteries by a cleaning process. It is trialling “a simple chemical remediation process to remove impurities from affected batteries”.
“Should this remediation approach be subsequently required, Redflow estimates the net cost of this process to be about AU$500 (US$377) per battery.”
Meanwhile, delivery of new batteries “has been paused pending the outcome of this further testing”. Redflow said it expects to resume customer shipments once “tests being conducted return satisfactory results”.
The company said it has about $1 million worth of product backorders, with 96 batteries in stock and another 120 batteries in transit from the factory.
Redflow said it has replaced, or is in the process of replacing, a total of 23 batteries in customer sites since January 2017 “under warranty for a variety of reasons”. Three batteries “were replaced due to routine and minor mechanical issues… these problems were resolved by changes to manufacturing processes”.
“Thirteen batteries were replaced due to operating cycle issues observed in the field that were the result of sustained operation of batteries in a manner not anticipated during in-house product testing,” Redflow said. “These issues were resolved via software updates to optimise the battery operating cycle.”
Seven batteries were replaced “due to a different observed failure mode”, which Redflow said arose “from a separate aspect of the battery operating cycle, where unexpected stress on the product is created in specific circumstances”. The company said it has produced a new software update to resolve that issue.