**Exhibit 31.2**

**CERTIFICATION**

| I, Han   Yongbin, certify that: |
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| 1.                              | I have   reviewed this Quarterly Report on Form 10-Q of China BAK Battery, Inc. for   the period ended March 31, 2006; |
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| 2.                              | Based on my   knowledge, this Quarterly Report on Form 10-Q 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 quarterly report; |
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| 3.                              | Based on my   knowledge, the financial statements, and other financial information included   in this Quarterly Report on Form 10-Q, 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 quarterly report; |
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| 4.                              | The   registrant’s other certifying officer 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 we have: |
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|                            | (a) | Designed   such disclosure controls and procedures, or caused such disclosure controls   and procedures to be designed under our supervision, to ensure that material   information relating to the registrant, including its consolidated   subsidiaries, is made known to us by others within those entities,   particularly during the period in which this quarterly report is being   prepared; |
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|                            | (b) | Evaluated   the effectiveness of the registrant’s disclosure controls and procedures and   presented in this report our conclusions about the effectiveness of the   disclosure controls and procedures, as of the end of the period covered by   this report based on such evaluation; and |
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|                            | (c) | Disclosed in   this report any change in the registrant’s internal control over financial   reporting that occurred during the registrant’s most recent fiscal quarter   (the registrant’s fourth fiscal quarter in the case of an annual report) that   has materially affected, or is reasonably likely to materially affect, the   registrant’s internal control over financial reporting; and |
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| 5.                              | The   registrant’s other certifying officer and I have disclosed, based on our most   recent evaluation of internal control over financial reporting, to the   registrant’s auditors and the audit committee of registrant’s board of   directors (or persons performing the equivalent functions): |
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|                            | (a) | All   significant deficiencies and material weaknesses in the design or operation   of internal control over financial reporting which are reasonably likely to   adversely affect the registrant’s ability to record, process, summarize and   report financial information; and |
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|                            | (b) | Any fraud,   whether or not material, that involves management or other employees who have   a significant role in the registrant’s internal control over financial   reporting. |

 

| By:    | /s/ Han Yongbin           |   |
|--------|---------------------------|--------|
|   |                           |   |
|   | Han Yongbin               |   |
|   | Chief   Financial Officer |   |
|   | May 10, 2006              |   |