| Cover | Mar. 31, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Mar. 31, 2022 |
| Document Information [Line Items] | |
| Entity Registrant Name | EOS ENERGY ENTERPRISES, INC. |
| Entity Central Index Key | 0001805077 |
| Amendment Flag | false |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-39291 |
| Entity Tax Identification Number | 84-4290188 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 3920 Park Avenue |
| Entity Address, City or Town | Edison |
| Entity Address, State or Province | NJ |
| Entity Address, Postal Zip Code | 08820 |
| City Area Code | 732 |
| Local Phone Number | 225-8400 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Common Stock | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Common stock, par value $0.0001 per share |
| Trading Symbol | EOSE |
| Security Exchange Name | NASDAQ |
| Warrant | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Warrants, each exercisable for one share of common stock |
| Trading Symbol | EOSEW |
| Security Exchange Name | NASDAQ |
