Custom Battery Packs

Cadex specializes in the design and manufacturing of battery packs and chargers. Combining these two capabilities enables us to provide you with a one-stop solution. The most important benefit is matching battery and charger to improve battery performance and extend service life, an improvement that cannot be realized with separate designs. 

Cadex has been providing battery charging and diagnostic systems since 1981. The driving force behind our success is a broad knowledge in electrical storage systems, innovative designs, superior product quality, first-class customer support and competitive pricing.

Customers turn to Cadex for advice to improve battery reliability and extend service life. We would also delighted to hear about your battery quirks.


Overview

Battery and Charger go Together like Horse and Carriage

Nowhere else does an advanced charger play a larger role than in a harsh environment. Ultra-fast charging, keeping the battery at prolonged high charging voltage and exposure to elevated temperatures lowers the service life. Charging below freezing further induces a cell imbalance, stresses the can be mitigated with a well-designed charger.

Cadex builds batteries that include SoC-readout, SMBus and BMS. These custom features work in unison with our chargers to receive the full benefit.

Designing a good pack begins with the selection of cells.
  • Low-cost cells serve mainly consumer goods. They are economically priced but have relatively short lifespan.
  • High capacity cells offer increased runtimes but the load current is limited.
  • Industrial cells deliver high current but offer lower capacity and are more expensive.

To lower stress level when charging batteries, a charger should include these features:
  • The speed by which a battery can safely be fast-charged is governed by temperature.
  • Ultra-fast charging should only be applied at a moderate temperature.
  • The charger should limit the time the cell stays at elevated voltage.
Cadex considers these requirements when designing industrial chargers.

Pack Assembly

Why Li-ion?

Li-ion for Renewable Energy

“The change to Li-ion is faster than the advancement of the Internet.”

  • Li-ion is less expensive per cycle with longer life than lead acid
  • No sulfation problem if battery is not fully charged
  • Potential for rapid charging solutions

Although higher in initial purchase price, the cost per cycle of Li-ion is cheaper than lead acid. Li-ion is superior to lead acid in size, weight and service life, reducing shipping cost.


  Lead Acid Li-ion
Lifespan 500 cycles at 50% DoD 1900 cycles at 90% DoD
Battery cost $21,000 $57,000
Cycle cost $42 $30


Replacing Large Battery with Li-ion

Li-ion batteries with loading capabilities of 1000A can be economically built using 18650 cells in a 4S50P configuration (4 in series, 50 in parallel). Li-ion has a different charge algorithm than lead acid it replaces and some modification may be needed. 

Cell Formats

Cell Formats

Li-ion Multi-cell Packs require voltage monitoring of each cell, current limiting and thermal management. To eliminate cell balancing, the cells must be matched. Larger packs should be designed to stop propagation if one cell fails.

Single-cell Packs do not need cell-matching. The safety circuit consists of voltage and current limiting. Single-cell packs can be made at a low cost

li-ion Battery
18650 cell
Li-ion Battery
Prismatic cell
Li-ion Battery
Pouch pack
Good cycling ability, long life, low price, large selection, 50% higher specific energy than prismatic and pouch cells.

Heavy; gaps with multi-cell packs. Not suitable for ultra-slim designs.
Compact design. Well suited for single-cell packs.

Less efficient in thermal management. Shorter cycle life. More expensive to fabricate.
Light and cost-effective. Large pouch may reach cost parity with 18650 in 2018.

Exposure to humidity and heat may shorten life; 8–10% swelling over 500 cycles.

Intelligent Batteries

FROM BASIC TO SOPHISTICATED

Cadex offers a comprehensive range of battery packs and charging technology, each designed of the optimal charge characteristics. While the EV battery has one of the best charging system and most advanced BMS technology to achieve an eight-year service life, Cadex attain similar performance by matching battery and charger.

  Battery Charger
Level 1 Regular battery pack Basic charger with redundant safety features
Level 2 Battery has SoC indication Basic charger with redundant safety features
Level 3 SMBus battery Hybrid, option to display digital battery information
Level 4 Custom BMS Provides specialty communications and functions
Level 5 Most Li-ion batteries Estimates health. Only passes if capacity above 80%

Cadex builds auto-clavable batteries for medical instruments, as well as packs that include a heating blanket to heat the cells to above freezing temperature before and during charging. The chargers regulate the charge to limit stress during cold temperature charging.


BMS Taken a Step Further

Batteries are increasingly being equipped with battery management systems (BMS) featuring fuel gauges that display state-of-charge, but the readings can be notoriously inaccurate and the battery needs calibration. A further drawback is the inability to estimate battery capacity, the leading health indicator. After charge, the reading always shows 100% even if the capacity has dropped to 50%.

Cadex is developing technology to estimate capacity as part of battery monitoring. This will enable an existing BMS to display battery state-of-health and provide end-of-life prediction. The technology is tailored for each battery type. Please call Cadex at [email protected] for more information.

The Spectro™ technology providing capacity estimation is a further development of electrochemical impedance spectroscopy (EIS). EIS uses complex modeling to derive the reserve capacity and improve CCA test results. BMS


Spectro-BMS™ for starter battery

Our objective is to package Spectro-BMS™ into a compact module for pole-mount on a starter battery or use on stationary batteries. Adding capacity allows accurate end-of-battery-life prediction, a task not possible with voltage and impedance readings. Cadex is seeking partners to co-develop.


Quality Assurance

QUALITY ASSURANCE

We commit to deliver the best possible quality and we've worked hard to develop and implement an efficient company-wide Quality Management System.

It is our policy to provide products and services that totally satisfy the expectations of our customers through the achievements of excellence in:
  • Quality
  • Product Value
  • Delivery
  • Continual Improvement
  • Conformance to appropriate specifications and contractual agreements
  • Accountability for product reliability and durability
Cadex is a certified defense supplier (ITAR Registered).
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