The battery requirements in an industrial motive application are quite different from a battery in a static application. The cell technology may be similar, but the safety aspects, reliability and operating conditions are very different. The industrial motive sector is one of the most onerous applications there is for any battery as these machines work 24/7 under considerable vibration and environmental stress, high C-rates, and can do many cycles in a single day. Downtime on industrial applications is critical, as generally used in a critical part of a logistics chain, so failure of a battery has high costs associated with it. The following features are useful in all applications, but particularly relevant to industrial motive machines.
Laboratory Accuracy BMS
Our Battery Management System (BMS) has a very long history, as development started in 2001, and has been used on a variety of battery chemistries. This dedicated BMS that is chemistry agnostic has over the years produced many unique insights, experience, and data collection that has given rise to many improvements and unique features. Early in our BMS development, before the advent of “IOT” becoming a buzzword, we saw the value of batteries being connected to a gateway online. Hence we started rolling our own “IOT” gateway and building our own connectivity modules. At the start as well, we realized that there was value to collecting very accurate battery information in the field for all batteries, and measuring parameters such as coulombs and energy, and using that data for battery analysis, machine system analysis, and early failure predictions. In the vein of accuracy, our latest BMS is aiming for a 1:500 000 dynamic range on both voltage and current measurement. A dynamic range this big means it can resolve 1mA changes and measure up to 500A. Even more exceptional is even with this dynamic range, it also has an extremely low offset of less than 10mA. This enables our BMS to measure coulombs in, coulombs out and coulombic efficiency with enough accuracy to be scientifically meaningful, and to do lifetime predictions. Another example of how useful this is, our State of Charge (SOC display value) is considerably better than 0.1% accurate in a normal daily charge/discharge cycle, and only typically drifts by considerably less than 0.1% per day when left idle. In addition to just battery and machine analysis, the data can provide very useful business metrics and value adds. In terms of machine drive or battery diagnostics, our BMS technology can do a simultaneous multichannel oscilloscope capture on every cell voltage, battery voltage and battery current, and send all these readings back wirelessly to our gateway. Our accuracy also extends to every individual cell, as every cell voltage is measured as a virtual four-terminal measurement, directly across cell terminals and excluding any interlink voltage drops. There are no common measurement or sense wires with adjacent cells as these give noise and inaccuracies, and all cell voltages are measured simultaneously, together with battery voltage and current. These simultaneous measurements are necessary to calculate battery impedance’s, and for the 3D state space models. The amount of balancing coulombs per individual cell is also measured and reported. The cell voltages are all measured simultaneously, to within a microsecond, as these are imperative for any cell impedance or SOH calculations. To our knowledge, most of the above are all unique learnings and features.
Global wireless connectivity
We can offer lifetime (15 year prepaid) global connectivity using our GSM connectivity options including 2G, 3G and NB-IoT. GSM is ubiquitous globally and has the bandwidth needed, and has been our focus as most suited to motive applications. We do also offer Wifi connectivity, and we are developing software to make a battery visible on a local LAN network.
Robust, Light and Optimum form factors
We have a cell compression method using a unique parallel expansion plate that acts to tension the exoskeleton battery box as well. The combined compressed cells and tensioned exoskeleton battery box gives structural rigidity with no added weight. The cells make up 80 – 87% of the weight on all our battery models. Compressed cells, together with tension bars and battery casing, means the cells are held in place from all six sides, making the battery itself tolerant to rotation and inversion. Extra cell insulation made from approved PET is also added to every individual cell. This extra insulation, together with cell compression, tension bars, flexible interlinks and tensioned exoskeleton battery box make the battery physically robust and tolerant to vibration, shocks, dropping and temperature cycling, while still being easily accessible in the field for service and repair. In addition to the exoskeleton casing, our direct cell to pack methodology and solid-state contactor allows us to make the smallest battery form factors possible using standard automotive prismatic cells. On a typical battery, the specific energy density is 145Wh/kg and volumetric density is 220Wh/l.
In summary, our battery mechanical design is tolerant to vibration, temperature cycling, drop test more than 5 times higher than the IEC standard, inversion tolerant, IP61, uses flexible laminated cell interlinks, cells compressed correctly, and yet still easily accessible in the field for servicing.
Efficient certified slimline chargers
Very efficient, slimline small form factor, PFC corrected on every phase, 3 phase and single phase chargers. The chargers have a simple “constant current to constant voltage” (CC to CV) charge profile, which is robust and reliable. Conventional chargers are designed for use in a battery bay and floor mounted, so they often fail when placed on the factory floor due to the amount of tyre dust in the air. Our chargers have replaceable air filters and are wall-mounted to try and avoid the more intense dust at floor level.
Battery and Machine Analysis
Collecting accurate battery data also allows in-depth analysis of both battery and of the machine operation it is used in. This operational data can be used to generate businesses value add metrics and reports. For example, hours operated, hours charged, usage patterns, but it can also generate more unique data, such as how efficient is a particular machine is at doing a job (measured classically with VDI cycle in kWh/h). Another example of our unique analysis ability is our data could be used to calculate actual live work rates, giving an indication of how busy the machine is, or report on busy periods. Operational improvements are also possible, for example, in rental access or cleaning machines, we generate alerts that prevent downtime such as battery not put on charge at end of shift. etc
Distributed Battery laboratory
Using our accurate data gathered from every battery, we are developing innovative 3D state space models to represent each battery that give a very powerful visual and analytical means to diagnose problems, see performance degradation, generate early warnings and do lifetime predictions. Our aim is to turn this concept into a very intuitive and powerful tool for evaluating vast amounts of battery data in the field, either of deployed batteries or of any new chemistry, without needing extensive laboratories or software. We aim to become the largest “distributed battery laboratory” in the world.
Guarantee and Accountability
The guarantee or warranty offered by many manufacturers are often not as comforting as they appear at face value, such as a long calendar lifetime of 10 years. The warranty is often prorated and discounted over the lifetime to the original value, and then only offered as a discount on a new purchase. In addition, there are usually a few other rejecting conditions. The better question to ask is, how is the performance of the battery over its lifetime proven, or disproved? For example, how does the customer demonstrate that the battery was always used within specification, as this will be the first point of refusal on a claim. Secondly, “cycles” is not a useful metric, as lithium can do many more “small” cycles than typically specified in datasheets for 100% DOD. Industrial motive applications are very high cycling applications as with opportunity charging, there can be many smaller cycles in a day. Hence, a more useful metric in this context is how many machine operating hours did the battery work for. This is proportional to how much work the battery does, or the total amount of energy the battery has delivered. Balancell BMS has the ability to measure energy input and energy output exactly and provide a guarantee based on this.
The entire battery history, of every parameter, is recorded for every minute up to 30 years internally (and sent to our gateway if online). The Total Energy Output in kWh, or total lifetime operating hours are all recorded. The data is all transparent and accessible to either honour the guarantee, or show real causes of abuse. The Real Amp-hour Capacity is viewable and measurable in the battery history for every discharge throughout its lifetime.
Power electronics integrated into battery
Our solid-state contactor (referred to as the “protector”) is unique at higher battery voltages and currents, operating up to 80V, 1000A. Solid-state does have limitations in terms of maximum voltages, but also many unique features, such as very being efficient, low resistance, unlimited on/off life, compact size, low power drive requirements, and ability to offer electronic current limits. This means it can also act as built-in pre-charge circuitry. It is easily configurable for multiple battery types. The easy drive, low power means it is relatively easy to add a layer of analogue electronic safety battery cutouts, as a failover from digital cutouts.
Solar panel direct charging
Our batteries and solid-state protector allow direct charging of the battery without any MPPT or other electronics needed.
Battery assembly technology and lean Manufacturing
Our modular BMS and battery technology allowing us to assemble prismatic cells directly into a battery, or referred to as “cell direct to pack”. Our production line has been designed and implemented with the best of batch and lean manufacturing principles, and is itself a modular production line. This means we have the ability to simply replicate the line and scale production fast. We are also in process of complying with all requirements for ISO9001. Our modular BMS and battery assembly technology also gives us the ability to produce new designs very quickly, and take them directly into production.
We are a diverse team with eclectic innovative ideas, and with a very broad, deep experience of battery design, power electronics, and system integration, from floor cleaners to electric vehicles.
Starting in 2000, with BMS solutions for lead acid batteries, to designing some of the first electric vehicle lithium battery for the joule electric vehicle, we have experienced many difficult problems and learnt many lessons along the way.
We hope we can pass these lessons and knowledge onto you, and save you time to make your transition quickly and easily into a fully battery powered electric future.