Introduction
Jiangsu Relince New Energy Technology Co., Ltd., established in November 2021, is a technology enterprise integrating the R&D, production, sales, and service of lithium battery cells. The company focuses on providing clients with the world’s most advanced tabless cylindrical battery cells and solutions. Its products simultaneously feature multiple leading performance characteristics, including high specific energy, high power, ultra-fast charging, and a wide operating temperature range.
Battery Network has acquired a tabless 21700 cell launched by Relince New Energy. The cell model is RS50, with a nominal capacity of 5000mAh. It supports 3C charging and 14C continuous discharge capability, with an AC internal resistance of ≤4mΩ. Furthermore, it boasts a maximum cycle life of 1500 cycles. The following section presents a teardown of this tabless cell, offering a detailed look at its internal structure and design.
Relince New Energy INR21700-RS50 Tabless Cell: Exterior
Cell model: INR21700-RS50,
Nominal voltage: 3.6V;
Nominal capacity: 5000mAh.
Maximum continuous discharge current:70A
The positive terminal cap of the Reiin New Energy INR21700-RS50 full-tab cell is made of alloy material and features a flat-top design, with three vent holes visible on the top.
The cell’s negative terminal is connected to the internal current collector via laser welding.
Teardown of the Reiin New Energy INR21700-RS50 Tabless Cell
After opening the cell’s seal and removing the positive terminal cap, the current collector plate is observed to be directly welded onto the safety valve.
A close-up view of the internal safety valve structure within the positive cap reveals its working principle: when internal pressure becomes excessive, the internal valve disc deforms, severing the electrical connection at the positive terminal and disconnecting the circuit. If the pressure continues to rise further, the valve disc ruptures to release gas and vent the pressure.
The current collectors for both the positive and negative terminals are connected to the core via laser welding.
An insulating layer of non-woven fabric is placed between the core and the cell casing.
The core’s positive electrode uses aluminum foil, wrapped with high-temperature resistant tape for insulation, while the negative electrode uses copper foil. The edges of the positive and negative electrode plates are left uncoated with active material to facilitate welding connections to the current collectors.
Teardown Summary
The Relince 21700 RS50 cell utilizes a stainless steel outer casing housing an internal core. Current collector plates are installed on both the positive and negative sides of this core, connected via laser welding.
The tabless design functions by welding the bare edges of the electrode plates directly to the current collectors. This configuration shortens the current path, reduces the cell’s internal resistance, and significantly enhances charge and discharge performance.
The positive current collector is laser-welded to a Current Interrupt Device (CID). This mechanism, integrated with the positive cap, provides overpressure protection. In abnormal conditions, such as overcharging, the CID activates to disconnect the electrical circuit and release internal pressure.
The negative current collector is also laser-welded, connecting directly to the cell casing which serves as the negative terminal.
Spacers and high-temperature resistant tape are positioned between the core and the casing. These components secure the core in place and provide insulation, ensuring safe operation.
Performance Testing: Reiin 21700 RS50
(The following performance data is based on specifications provided by the manufacturer or standard test conditions.)
The Reiin 21700-RS50 cell, with its tabless design, demonstrates a performance profile characterized by high capacity, high power output, and excellent fast-charging capability.
Key Performance Metrics:
- Nominal Capacity: 5000mAh
- Charging Performance: Supports 3C fast charging, enabling a full charge in approximately 20 minutes.
- Discharge Performance: Capable of continuous 14C discharge, delivering high current for power-demanding applications.
- Internal Resistance: Exhibits an exceptionally low AC internal resistance (≤4mΩ), which is crucial for minimizing energy loss and heat generation during high-current operation.
- Cycle Life: Designed for long-term reliability, with a cycle life of up to 1500 cycles while maintaining over 80% of its original capacity.
This combination of high energy density, low internal resistance, and robust power handling makes the RS50 cell suitable for applications requiring high power and rapid charging, such as high-end power tools, electric vehicles, and advanced energy storage systems. The tabless structure is the key enabler for this performance, significantly reducing the current path and thus the cell’s internal resistance.
