Exhibit 31.2

Certification Pursuant to Section 13a-14 of the Securities Exchange Act of 1934 of Yongbin Han (Chief Financial Officer)

I, Yongbin Han, certify that:

| | 1. | I have   reviewed this Form 10-Q for the quarterly period ended December 31, 2006 of   China BAK Battery, Inc. (registrant);                                                                                                                                                                                   
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| | 2. | Based on my   knowledge, the report does not contain any untrue statement of a material   fact or omit to state a material fact necessary to make the statements made,   in light of the circumstances under which such statements were made, not   misleading with respect to the period covered by this report;
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| | 3. | Based on my   knowledge, the financial statements, and other financial information included   in this report, fairly present in all material respects the financial   condition, results of operations and cash flows of the registrant as of, and   for, the periods presented in this report;                  
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| | 4. | The   registrants other certifying officers and I are responsible for establishing   and maintaining disclosure controls and procedures (as defined in Exchange   Act Rules 13a-15(e) and 15d-15(e)) for the registrant and have:                                                                               
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| | 5. | The   registrants other certifying officers and I have disclosed, based on our   most recent evaluation of internal control over financial reporting, to   the registrants auditors and to the audit committee of the registrants   board of directors (or persons performing the equivalent functions):
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|Date:  February   9, 2007       | 
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|/s/ Yongbin   Han               | 
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|Yongbin Han                     | 
|Chief   Financial Officer       | 
|(Principal   Financial Officer) | 
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