Panasonic’s New “NCR18650BD-Improved” Lithium Ion Battery Requires No State of Health CheckSeptember 22, 2020 by Gary Elinoff
Through bypassing this usual requirement of lithium ion battery (LiB) application, costs are saved and reliability is increased.
Panasonic has introduced it’s NCR18650BD-Improved to its NCR18650 group of cylindrical LiB cells, all aimed at motive applications. The new battery is targeted at applications requiring both high energy storage capacity and long life.
Image courtesy of Panasonic
Introduced earlier, the NCR18650PF is targeted at standard requirements, while the NCR18650GA is aimed at applications requiring the highest energy storage capacity.
All units supply 3.6 volts. The NCR18650PF and the NCR18650GA store 2700 and 3300 milliamp hours (mAh), respectively, at 20 ℃. The new NCR18650DB-Improved is specified at 2910 or 2980 mAh, depending on use case.
What are State of Health Checks?
A LiB is a tricky device, and their “state of health” needs to be constantly monitored by a battery management system. The measurement is often reported in percentage points, starting from a baseline of 100% at the time the unit is initially manufactured.
Unfortunately, there are no generally accepted industry standards, not even any unanimity over the parameters to be measured. Common state of health (SOH) benchmarks include:
- Number of charge/discharge cycles
- Battery internal resistance
- How well the battery accepts charging
- Energy storage as a percentage of the original capacity
- Output voltage compared to the original value
The different uses an LiB might be harnessed to may determine the most important parameters to be measured in determining its state of health. For EV’s, for example, total energy storage capacity is king. For hybrids, power, the amount of energy that can be delivered in a finite amount of time, is vital.
In the case of the NCR18650BD-Improved, the lack of need for a SOH system presupposes that the battery will be charged from 4.15 volts. This level stresses the device less than a higher value would.
Key Specifications for the NCR18650
Some of the most important parameters of the NCR18650 group of batteries are summarized below. Note that for the NCR18650BD-Improved, two use cases are mapped out.
Members of Panasonic’s NCR865 group compared. Image courtesy of Panasonic
As the diagram below summarizes, even after 1200 charge/discharge cycles, the NCR18650BD-Improved can be charged to approximately 80% of its original capacity, while the other two hover at about 65%.
Charge capacity for the members of the NCR18650 group of batteries. Image courtesy of Panasonic
“Frankly spoken”, Norbert Depresles, Section Head of Business Development EMEA from Panasonic Industry Europe says, “the NCR18650BD-Improved fits almost everywhere and demonstrates a proven performance stability over a wide range of discharge rate, temperature and cycle life.”
The Luxury of a Battery that can be Forgotten
Even with 4.15V charging, at each charge/discharge cycle, the new NCR18650BD-Improved achieves a higher energy storage capacity when compared to the earlier to PF cells. Engineers who’ve struggled with designing and implementing the necessary external circuitry necessary for the safe operation of touchy LiBs will certainly appreciate a battery that can, literally, be installed and forgotten.
As Mr Depresles puts it, “on the meta-level, the NCR18650BD-Improved core feature is being unpretentious in every regard.” He goes on to state that, “having it reliably working in almost all environments and thus achieving cost reduction is what everyone needs. I’d even say, with the NCR18650BD-Improved, we have taken a crucial step towards the battery that ‘can be forgotten’ in the positive sense.”