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Battwoo’s Second-Life EV Batteries — When an 80 % Acceptance Threshold Overlaps the Retirement Distribution, Incoming Screening Becomes the Bottleneck
French startup Battwoo refurbishes into stationary ESS only those retired EV batteries that retain more than 80 % of their capacity, while EV batteries typically retire at 70–80 %, and it says a 500 kWh system costs about 30 % less than one built with new batteries¹. When the retirement distribution and the acceptance threshold overlap like this, the acceptance rate is low: assuming incoming SOH with a mean of 76 % and a standard deviation of 3 %, the acceptance rate is 9.1 %, so 11.0 modules must be tested for every module shipped. At an assumed 1 MWh per month of shipments, 23.9 full-capacity test channels are needed,…
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Linking BMS Operating History to the Battery Passport: Why Sampling and Retention Must Be Separated
When the dynamic BMS data required by Article 14 and Annex VII of the EU Battery Regulation (Regulation (EU) 2023/1542) is linked to the battery passport[1], the variable that determines data volume is not the sampling period but which layer retains what. At a site of roughly 100 MWh (111,488 cells, assumed), retaining all raw cell data at 1 s accumulates 42.2 TB per year and 421.9 TB over 10 years, whereas aggregating the Annex VII parameters into daily rack-level records yields about 0.05 GB per year, roughly 1/840,000 of that. Conversely, sampling a 20 s abnormal event at a 60 s period drops the detection probability to 33.3%. A…





