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GMET Mfg Processes Co., Ltd.

About the GMET 

GMET company is organized by a team of engineers who had been long time experienced in the fields of Electrochemical, Precision Mechanical manufacture and Electrical engineering. Most of engineers had been also producing small size of prismatic Li-battery cells applied in the commercial devices such as cellular phones, pad and electric books more than 8 years with more than 100 millions of Li-battery cells delivery experiences. The type of Li-battery experienced are Lithium cobalt oxide (LiCoO2) batteries, Lithium polymer battery and LiFePO4 (磷酸鋰鐵電池,磷酸鐵鋰電池). The R&D engineers have the capability of developing Electrolyte to meet the cell capacity of customer’s requirement in certain range. The sources of cathode material are from two authorized suppliers in Taiwan. 


Currently electrical engineers usually connect more than thousands of cells in the application of Li-Battery. However if there were one single cell with 60 Ah, the numbers of cells through series or parallel connection to achieve high capacity application would be significantly reduced. It also reduce the electrical resistance when pack those small capacity cells as a battery by bridge connectors.


With a vision of future high capacity and safe battery required in the applications of EV, Electric Bus, Electric motorcycles, storage, and replacement of lead Acid battery for environmental protection, to develop a differential design of high capacity cell would be necessary in the world, the company was established in year 2011. 

GMET has set up three divisions in the company for the operation:


The Cell enclosure division is dedicated to design and development on the enclosure and connectors for cells. The high capacity Lithium battery cells must have a safety protection enclosure to assure its perfect performing on the output of electric power in the applications. 


The Cell manufacturing division has set up an in house production line with capacity of 20,000 kWh annually (400 pieces of 60AH daily). A laser cutting process has developed to prevent the chips occurred on the edge of each cathode and anode sheets. The production capacity can be expanded to meet the requirements of customers in five months.


The Cell pack division is dedicated to sourcing BMS or working with customers to develop BMS on each different requirement of application to assemble cells as a  battery pack in house. It also takes advantages of developed connectors to pack cells in terms of low AC impedance and longer stand of cells life. 



Objectives of GMET


1.To develop high capacity of Li battery Cell, 3.2V 20 AH and 3.2V 60AH.

2.To develop effective Relief Vent for the safety of high capacity of Li-Battery Cell.

3.To develop aluminum enclosure for High capacity of Li-Battery Cell.

4.To improve the electrical resistance when cells packed through series or parallel connections.

5.Initial target of Li-Battery cost per KW is US$500.



Battery Cell Enclosure


The enclosure division is dedicated to the design and development of variant size of high capacity cell sealed in an aluminum shell. The key challenge design is to develop Square Surface Terminal (SST), which provides a non-interrupt path for electron flow from one tab of electrode to terminal outside of cell. The SST design eliminates the screws inside of the terminal. In addition the bridge connector connecting terminals between two cells is tightened by indirect screws that reduce the possibility of loosen between terminals and bridge connectors when battery is operated in a vibration movement.


In most of the high power applications users usually connect small capacity of battery cell, like 18650 cylindrical cells to achieve its applications requirements. It always requires more than thousands of cells in one application. However if there were one single cell with 60 Ah, the numbers of cells to series or parallel connection would be significantly reduced. It also reduce the electrical resistance when pack those high capacity cells as a battery by bridge connectors. The heat would not generate for a battery in high output or long service if the electrical resistance of bridge connectors can be effectively controlled in minimum. By this way the performance of battery can be significantly improved to achieve the expectations of electrical engineers.


Design of Relief Vent

Vent open can be controlled by Pressure or by Temperature


The relief vent on the SST is a destructive mechanism which would discharge Electrolyte when the vapor pressure reach 0.3~0.6 Mpa (0.6 m Pa or 5.9 atm, 87 psi or 6.11 Kg f/) in an abnormal operation condition. The relief vent on cell is able to sustain external shock & vibration force from operation without damage.

The most advance mechanism is Vent Open Controlled by Temperature at95℃ when battery cell occurs abnormal operation situation.


There is no relief vent designed to destroy cells by temperature control in the world. The dangerous of battery cell is when thermal runaway happens in the cell that is the chemical reaction temperature at 380℃. It would be much effective if we can discharge the electrolyte to cool down the cells at 95 ℃ before it gets runaway temperature 380℃ in an abnormal cell. The cut off point for abnormal cell at 95℃ is much earlier than the critical temperature 140℃.

The Technical Advantages of GMET

1.Capability of Electrolyte Chemical Composition development. Li-Fe, Li-Mn,            Li-Cobalt Li- Polymer etc,.
2.Capability of Enclosure design on both of soft and hard shells.
3.Capability of Process Machinery design.
4.Experienced of Cells Mass Production.
5.In house Cells manufacturing Capacity.
6.Battery Pack Manufacturing Capability.




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