Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2023	Nov. 01, 2023
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
Entity Registrant Name	AEVA TECHNOLOGIES, INC.
Entity Central Index Key	0001789029
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-39204
Entity Tax Identification Number	84-3080757
Entity Address, Address Line One	555 Ellis Street
Entity Address, City or Town	Mountain View
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94043
City Area Code	650
Local Phone Number	481-7070
Entity Common Stock, Shares Outstanding		223,445,507
Document Quarterly Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	DE
Entity Interactive Data Current	Yes
Common Stock [Member]
Document Information [Line Items]
Trading Symbol	AEVA
Title of 12(b) Security	Common stock, $0.0001 par value per share
Security Exchange Name	NYSE
Warrant [Member]
Document Information [Line Items]
Trading Symbol	AEVA.WS
Title of 12(b) Security	Warrants to purchase one share of common stock
Security Exchange Name	NYSE