| Cover | Jul. 14, 2023 |
| Document Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Jul. 14, 2023 |
| Entity Registrant Name | FREYR Battery |
| Entity Incorporation, State or Country Code | N4 |
| Entity File Number | 001-40581 |
| Entity Address, Address Line One | 22-24, Boulevard Royal |
| Entity Address, Postal Zip Code | -2449 |
| Entity Address, City or Town | Luxembourg |
| Entity Address, Country | LU |
| City Area Code | 352 |
| Local Phone Number | 621 727 777 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Entity Tax Identification Number | 00-0000000 |
| Entity Central Index Key | 0001844224 |
| Amendment Flag | false |
| OrdinarySharesWithoutNominalValueMember | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Ordinary Shares, without nominal value |
| Trading Symbol | FREY |
| Security Exchange Name | NYSE |
| WarrantsEachWholeWarrantExercisableForOneOrdinaryShareAtAnExercisePriceOf1150Member | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Warrants, each whole warrant exercisable for one Ordinary Share at an exercise price of $11.50 |
| Trading Symbol | FREY WS |
| Security Exchange Name | NYSE |
