Research on Restrain on Thermal Runaway Propagation
Research on Restrain on Thermal Runaway Propagation,
Research on Restrain on Thermal Runaway Propagation,
▍BSMI Introduction Introduction of BSMI certification
BSMI is short for Bureau of Standards, Metrology and Inspection, established in 1930 and called National Metrology Bureau at that time. It is the supreme inspection organization in Republic of China in charge of the work on national standards, metrology and product inspection etc. The inspection standards of electrical appliances in Taiwan are enacted by BSMI. Products are authorized to use BSMI marking on the conditions that they are in compliance with safety requirements, EMC testing and other related tests.
Electrical appliances and electronic products are tested according to the following three schemes: type-approved (T), registration of product certification(R) and declaration of conformity (D).
▍What is the standard of BSMI?
On 20 November 2013, it is announced by BSMI that from 1st, May 2014, 3C secondary lithium cell/battery, secondary lithium power bank and 3C battery charger are not permitted to access to Taiwan market until they are inspected and qualified according to the relevant standards (as shown in table below).
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Product Category for Test |
3C Secondary Lithium Battery with single cell or pack ( button shape excluded) |
3C Secondary Lithium Power Bank |
3C Battery Charger |
Remarks: CNS 15364 1999 version is valid to 30 April 2014. Cell, battery and Mobile only conduct capacity test by CNS14857-2 (2002 version).
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Test Standard |
CNS 15364 (1999 version) CNS 15364 (2002 version ) CNS 14587-2 (2002 version)
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CNS 15364 (1999 version) CNS 15364 (2002 version ) CNS 14336-1 (1999 version） CNS 13438 (1995 version) CNS 14857-2 (2002 version)
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CNS 14336-1 (1999 version) CNS 134408 (1993 version) CNS 13438 (1995 version)
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Inspection Model |
RPC Model II and Model III |
RPC Model II and Model III |
RPC Model II and Model III |
▍Why MCM?
● In 2014, rechargeable lithium battery became mandatory in Taiwan, and MCM began to provide the latest information about BSMI certification and the testing service for global clients, especially those from mainland China.
● High Rate of Pass: MCM has already help clients to obtained more than 1,000 BSMI certificates till now in one go.
● Bundled services: MCM helps clients successfully enter multiple markets in worldwide through one-stop bundled service of simple procedure.
The thermal propagation of a module experiences following stages: Heat accumulation after cell thermal abuse, cell thermal runaway and then module thermal runaway. Thermal runaway from a single cell is not influential; however, when the heat spread to other cells, the propagation will cause a domino effect, leading to the thermal runaway of the whole module, releasing massive energy. Figure 1 shows the result of thermal runaway test. The module is on fire due to irresistible propagation.The heat conductivity inner a cell will be different according to different directions. The coefficient of heat conductivity will be higher in the direction parallel with the roll core of a cell; while the direction that is vertical to the roll core has lower conductivity. Therefore thermal spread from side to side between cells is faster than it does through tabs to cells. Therefore the propagation can be seen as a one-dimension propagation. As battery modules are designed for higher energy density, the space between cells is getting smaller, which will worsen thermal propagation. Therefore, suppressing or blocking the spread of heat in the module will be considered as an effective way to decrease hazards.We can restrain thermal runaway actively or passively.1)Set cooling pipes on the bottom or the inner sides of a module, and fill with cooling liquid. The flowing of cooling liquid can effectively decrease the propagation.
