DCS Battery Tech

Here at DCS, designing lithium batteries is not only our bread and butter, but we love this safe, stable, robust, and high-performance cell chemistry so much that we decided to develop our own range of Battery and Cell Management Systems in 2015.

DCS Battery Management System:

What was the objective? Well, the reason we embarked on this project was that all the basic Chinese designed BMS’s are just protection boards, and it is hard to call them a BMS when they don’t do any cell balancing or provide any means of programmability for various parameters and cell control. A lot of Battery Management Systems that we have tested were using inferior PCB engineering design techniques and poor components. That means continuous performance above 100A was more or less impossible, and reliability was also questionable when pushing above 100A with those Battery Management Systems.

Our key BMS objective was to develop a high-performance 200A BMS that could do;

  • 200A continuous operations using high-quality components
  • To have a minimal increase in temperature at peak output current (as these circuit boards are installed inside battery packs, limiting internal heat build-up that is crucial for the longevity of the battery cells).
  • Designed for engine cranking applications, it has to deliver a minimum of 1200LCA’s for 10 seconds (because of the limited voltage drop with suitable lithium cells, it’s very easy to crank over modern engines. Most engines will start in under 1sec, so 10 seconds is plenty). CCA’s don’t apply to lithium batteries as this standard was developed for lead-acid batteries and needed to deliver 30 secs of cranking amps. When a lithium battery is controlled via a BMS, the correct terminology is LCA = Lithium Cranking Amps based on delivering 10 secs of cranking amps.
  • Suitable for high temperatures applications, e.g. engine compartments. It will be stable up to 180 degrees C.
  • Bluetooth and WiFi connectivity in order to develop a comprehensive app platform
  • Pass MIL vibration testing standards (to open up the development of batteries for just about any application).

In a nutshell, the design needed to be tough and reliable for those who use them in the field with no room for error. The construction materials, coating and surfaces, assembly techniques are critical in designing a reliable system. After submitting our brief to all major leading manufacturers in Europe, Japan, USA and Korea, we assessed their expertise and ended up working with a leading and well known Japanese semiconductor manufacturer.

This is a typical Chinese 100A 4S BMS design

This is the DCS 4S 200A BMS

After three years of development, in early 2018, we were satisfied with the circuit board stress testing and released the first batch of our newly developed BMS’s right across our entire 4S (12V) & 16S (48V) battery range. At the same time, we hired an app development team to start working on the software integration to launch our first app platform. The first GEN1 BLE DCS BMS’s that featured Bluetooth chips were launched in OCT 2019. The app platform required a lot of tweaking both on the hardware and software front, and our GEN2 BMS’s were released in mid-2020 along with a more stable app platform with a new design scheme. Our latest GEN3 BLE BMS’s had been released in JAN 2021. The accuracy and stability of the DCS LFP App monitoring system is now very mature and refined. Some additional features had been added along with the ability to create custom battery names. We can produce our DCS BMS technology in any continuous rating range from 10A to 200A with our comprehensive BLE DCS LFP App platform.

DCS Cell Management System:

Having developed such an industry-leading and reliable BMS, it made no sense to combine the cell balancing system together with the BMS. So with our many years of experience in designing and maintaining lithium batteries, we have developed a stand-alone CMS to compliment our BMS. CMS? What? OK, so there are two ‘theories’ of cell balancing in the lithium world passive and active. Passive balancing is a cheap inferior method of cell management as it can burn resistors in an attempt to bleed cell strings. In contrast, active cell balancing is a more complex and efficient balancing technique that redistributes charge between battery cells during the charge and discharge cycles.

Passive balancing has two fundamental setbacks;

  1. Heat: We don’t want unnecessary heat build-up inside a battery pack. The less internal heat, the lesser the impact on the battery cells over time
  2. Resistors have a limited service life, and once they fail game over, you have no cell management. But more importantly, they can fail in such a way in which they will keep drawing power and eventually destroy the cells.

Active balancing is the only way to manage lithium cells correctly. There are many ways to design an integrated circuit (IC) to actively manage cell strings. At DCS, we have tested well over 10 different methods of active balancing IC’s over the years and, in the end, again decided to develop our own active management circuit boards with the best-combined techniques based on our stress testing. Our in house PCB design engineer Max, designed our circuit boards to again meet the following criteria:

  • High current movement (our latest boards now achieve 3.7A dynamic movement per channel)
  • Thermal management to ensure the boards remain reliable in harsh environments
  • Be able to withstand maximum current and thermal loads to ensure long term reliability
  • Fail-safe design, if any component fails, it won’t compromise the battery pack (not consume power from the battery cells)

This is the DCS 16 channel CMS

There are, of course, some other software features and parameters, which we can’t disclose on this page to the public, as well as some very fancy hardware. But what our latest 04 channel and 16 channel CMS’s do is they can easily manage up to 1000Ah battery banks. So, for example, if you wanted to use our 16 channel CMS’s you could run a 51.2V 1000Ah single battery pack, which would be 51.2kWh in size! The DCS 15kWh batteries are just shy of 300Ah in capacity, so one can only imagine the tight CMS control these batteries are under, and that’s why we back them with a 10 year / 80% capacity warranty.

The DCS 16 channel 59.2A active cell balancing system is so powerful that it will change the battery storage market forever. With this system, the lithium market will continue to dominate for the foreseeable future. Of course, all DCS batteries now feature both our BMS & CMS circuit boards.

We design all our own PCB hardware and the circuit boards are tested to withstand a minimum of 10 years of severe abuse. This video is the MIL-STD 810G Method 514.6 which includes 4 procedures for different modes of vibration.