Why Nickel Zinc?
In terms of energy density and cost effectiveness Zinc-Nickel batteries are theoretically very promising. Coupled with additional features such as high power density, safety, and wide operating temperature, as well as environmentally friendly production process with no hazardous materials, these batteries emerge as a competitive technology in the rechargeable battery space.
First rechargeable Zinc-Nickel battery has been patented by Thomas Edison in 1907. There has been many research on Zinc- Nickel batteries since then. However no one has been able to address two main issues with Zinc- Nickel Batteries which are internal short circuit and Zinc anode passivation. Traditional solutions to solve either of these problems exacerbate the other.
As a result of our rigorous research we were able to solve both of these issues without compromising either one. At the same time we made significant improvements on other parameters such as manufacturing process, cost, and safety.
Main Technology Statement - Solution of the problem and the perfections.
Traditional zinc-nickel batteries suffer from:
Dendritic growth : Dendrites grow in to separator membrane short circuiting the battery. These are large needle like zinc protrusions.
Surface passivation : In an alkali environment zinc surface can deliver only a limited ampere-hours before becoming passivated. If you try to extract more current after that limit the passivation becomes non-reversable.
Zinc migration (Shape change) : During charge-discharge cycles zinc tends to move around in the battery in the forms of highly soluble zincates. This hurts zinc and nickel utilization ratio. Ultimately causing bridges between (+) and (-) electrodes causing short circuit.
Hydrogen evaluation : This causes discharge/charge amp-hours ratio to go below unity. Discharging the zinc electrode without discharging the nickel electrode hence creating a charge asymmetry. Also increase the internal pressure eventually causing a leak .
These problems though not catastrophic, reduces battery life and capacity in general.
In the zinc electrode we use a matrix with extremely low zincate mobility. This creates zinc metal in the form of nano-dendrites with an extremely large active surface area. A large surface area means high power and capacity for the battery.
Zinc electrode with an extremely low zincate mobility creates a zinc metal in the form of nano-dendrites with an extremely large active surface area. This basically solves the problems (i), (ii) and (iii) and alleviates problem (iv).
“While solving the historical problem Technology has been perfected with both physical and chemical developments. ”
Comparison chart -Real figures supported by finished test results
The only technology that perfectly optimizes all parameters at the same time
History of - Technology & Company
First Desktop Prototype
•Seeing that the battery technology was the main obstacle for the rapid growth of EV market, the founders decided to develop a low-cost battery alternative with competitive features.
•Ni-Zn was known to have high energy density, but there were chronic problems with dendrite formation.
•The first solution was to increase the zinc surface to reduce dendrite formation
Baseline: First signs of hope that a solution might be found for dendrite problem
•A laboratory was founded with the necessary equipment including a 24-channel computer operated battery tester
•Mold for desktop prototype.
•Support from IYTE Chemicals Department
•Raw material research and first procurement through import
Baseline: Formal studies were carried out in a well-equipped laboratory
• Battery molds revision
• Many of the fundamental factors that were critical for the battery were understood
• More refined sourcing of raw materials
•Revisions in the formula
•Some psychical improvements
Baseline: First prototypes with competitive qualities: 300-350 cycle life reached with a 70 Wh/kg prototype
•Very competitive results achieved with design revisions: 80% capacity after 1000 cycles (with maintenance)
•Different charge/Discharge regimes were tried with no deterioration
•Tests revealed that this battery can be exposed to instantaneous high voltage safely as part of its normal operation, enabling applications in different fields.
Baseline: Promising results are achieved with desktop prototypes. The next step is to start producing field prototypes for specific uses.
About the Company
OCALI Inc is a technology development company, founded in 2007 by Dr. Ogan OCALI in Izmir Technology Development Center (İZTEKGEB), located in Izmir Institute of Technology (İYTE) for developing innovative products/projects with commercial potential.
The team currently consists of 5 engineers (3 with doctoral degrees and 2 C level engineers) and a legal advisor.
Ocali team set out to produce low-cost rechargeable battery that will provide optimized solutions to a range of applications where the two dominant battery technologies, lead-acid and Li-ion, lack in satisfying customer needs. Ni-Zn was chosen for its high energy density and the team succeeded in overcoming problems in development.
Ogan Ocalı founder of Ocalı Inc. is the key visionary behind the innovative technologies. He co-founded Mojave Inc. a start-up in 2002 in Silicon Valley, which was later acquired by Magma Design Automation in 2004 for $140M.
Nickel-zinc combination was tried for batteries since early 1900s, however due to certain technical problems, it never achieved widespread use.
Ocalı team has been working on developing the concept and testing desktop prototypes since 2013, expanding the range of test parameters through time. As a result, they have succeeded in overcoming the critical problems posed by the Ni-Zn formulation and achieved competent results in terms of the main parameters.
The tests reveal that Ni-Zn battery is able to perform superior to lead acid in terms of power density, energy density, charge/discharge rate, deep discharge capability, also has a longer cycle life (retaining most of the capacity), is safer in terms of raw materials, easier and safer to dispose after use, needs less frequent maintenance and finally has a lower long term cost. Due to these qualities, it has the potential to replace lead acid batteries in many applications and also provides cost advantages to compete with lithium-ion batteries.
The initial works reveal that the Ni-Zn battery may be most useful where energy density and safety/reliability are the main concerns, such as electrical work machines (forklifts), marine use and vehicle start stop (SLI).
As the next step, the company plans to batch produce field prototypes for marine, SLI and forklift applications and refine the product design according to feedback.