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Summary of significant accounting policies - Additional Information (Details) - USD ($)
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Summary Of Significant Accounting Policies [Line Items]    
Value Added Tax Description The Company is subject to VAT for selling merchandise. The applicable VAT rate is 11% or 13% or 17% (depending on the type of goods involved) for products sold in the PRC. The applicable VAT rate of 17% and 11% decreased to 16% and 10% starting from May 2018, and further decreased to 13% and 9% from April 1, 2019.  
Loan payable to third parties $ 7,002,385 $ 306,600
Restricted cash 422,832 220,109
Restricted cash remaining frozen bank balance $ 422,832  
Warranty period 12 months  
Income tax examination, expire 3 years  
Unsecured loan    
Summary Of Significant Accounting Policies [Line Items]    
Loan payable to third parties $ 7,002,385 $ 306,600
Loan, interest rate per annum 6.00%  
Loan, maturity term 1 year  
Maximum    
Summary Of Significant Accounting Policies [Line Items]    
Restricted Cash Minimum Balance Maintain Percentage 100.00%  
Minimum    
Summary Of Significant Accounting Policies [Line Items]    
Restricted Cash Minimum Balance Maintain Percentage 0.00%  
Warrant [Member]    
Summary Of Significant Accounting Policies [Line Items]    
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 6,557,635 6,557,635
Warrant [Member] | Split-adjusted    
Summary Of Significant Accounting Policies [Line Items]    
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount 655,764 655,764
Suzhou E-Motor [Member]    
Summary Of Significant Accounting Policies [Line Items]    
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners 30.00%