1 of 14

SPARKY

ICAMES 2023

Bogazici University

Aaron L | Patrick M

The Clean, Carbon Neutral, and Cost Effective Battery System for Disaster Response

2 of 14

Table of Contents

What Inspired Me?

What Makes Our Battery Different?

Expanded Engineering View

Process Flow Chart

Source of our Battery

Battery Degradation

SPARKY’s Battery System

SPARKY’s Safety System

Bill of Materials (BOM)

Conclusion

3 of 14

What Inspired Me?

ELEMENT Battery Array

ELEMENT Battery Circuitry

4 of 14

What Makes Our Battery Different?

Cost Effective: $40 / cell our battery pack can be constructed at a cost of just $80!

Carbon Neutral: Utilizing batteries that would have been otherwise e-Waste, we are giving these battery packs another chance at life.

Electronically Simple: No only is our battery pack easy to construct, it is electronically simple with no need for soldering, advanced tooling, doesn’t require an electronic background to operate.

Exploded View

SPARKY

5 of 14

Exploded View / Designers Perspective

Side View

NEMA 5-15 Interface

Engineering Drawing

SPARKY

6 of 14

Process Flowchart

The system's basic functionality can be described as follows: the battery modules are charged when the power grid is operational. In the event of a power outage, the battery modules can also be charged via an optional energy conversion source such as a solar panel.

As an energy storage device, Sparky's primary purpose is to store energy when it is available and release it when needed. The device can store energy for as long as necessary, and it's recommended to keep it charged at 80% capacity for optimal battery storage while minimizing degradation, which may occur with higher charges.

When a disaster strikes, the device can be activated by simply turning it on and connecting the necessary electrical load. The inverter, whose purpose is to convert DC power to AC power, is used for devices that require alternating current, which is what you will find through the receptacles in your wall. For devices that require direct current, the inverter's USB port can be utilized.

7 of 14

Parent Vehicle (Battery Source)

Second (ZE1) Generation Nissan Leaf

2017 – Present

First (ZE0) Generation Nissan Leaf

2011 - 2017 Model Year

Source of our Battery

24 kWh 384 Volt Battery Pack

2013 - 2015 Model Year

Source of our Battery

8 of 14

Battery Degradation: Why We Used Leaf Cells?

Lithium Battery Degradation Curve

Battery Degradation proportional to the amount of heat that the battery is subject to, throughout its lifespan
Modern Electric Vehicle OEMs such as Tesla have implemented advanced liquid cooling systems to draw heat away from batteries ensuring the optimal lifespan of its battery.
When the first generation Nissan Leaf was introduced, EV battery technology was still in its infancy ultimately resulting in poor lifespans of its batteries.

Like a plant needs sunlight to live, too much sunlight will kill the plant. This is the same case with lithium batteries, a low ambient temperature will result in a reduction in performance, but any temperatures above 45 degree centigrade ambient will result in the acceleration of permanent cell degradation.

Now we will use the common 18650 Lithium Ion battery cell to illustrate how temperature has a proportional effect on cell longevity.

If we look at the illustration on the screen that displays the battery capacity versus the operating temperature of the cell that the test was conducted in, we observe an additional 1% decrease in cell capacity just by conducting our battery tests in a environment at 25 degrees versus a 55 degrees environment. This is further exacerbated, as we progress later into the lifespan of the battery, where an additional 9% decrease in battery capacity is observed over 250 cycles.

To avoid cell degradation from heat, EV OEMs such as Teslas have copper heat pipes that run alongside the battery cells channeling cooling liquid to a radiator that passively cools the liquid as the vehicle is in motion. These advanced liquid cooling systems not only require a significant amount of engineering to run efficiently, but are expensive to include on a car even more so in 2013 when this technology was not readily available.

As you can probably guess, this is exactly why there are an abundance of Nissan Leaf that have reached the tailend of it’s operating capacity in a electric vehicle. This issue has created a e Waste issue as Lithium batteries are not easily recyclable. Lucky for us, I was able to repurpose these batteries that previously yielded the ability to push a 3000 pound vehicle to now powering a small 500 watt inverter.

9 of 14

SPARKY's Battery System

Parent Vehicle: Nissan Leaf (First Generation) 2012 - 2017 Model Year

Module Count in Vehicle: 96 = 384 V @ 24kWh

Module Layout: 48S 2P

Battery Chemistry: Lithium Manganese Oxide LiMn₂O₄

Battery Configuration

Cell Rating: 4.2V 16.25aH Capacity

Module Layout: 2 Series in 2 Parallel (4 cells per module)

Individual Cell

Cell Module (4 Cells)

Our Cell Module (2 Modules)

The 24 kWh battery pack inside of the Nissan Leaf is a 48 Series 2 Parallel (48S 2P) that outputs a voltage of 384 volts at 24 kWh or 24000 watt hours. This means 96 battery modules work in conjunction to create a big pack. Inside of every battery module is 4 cells in a 2S 2P configuration. The cells use a flat pack pouch cell identical to the ones you would find in your cell phone but with a greater capacity. Just as a reference, each cell has approximately 5 times the capacity of your standard cell phone battery and the total battery pack of the car has 384 of them.

Now that we understand more about the source of the battery pack inside of SPARKY, I can dive into the battery that is found in SPARKY.

Sparky is powered by 2 cell modules, totalling 8 individual cells. In a 2S 1P configuration to make it a 12V system. The reason why we aimed to make it a 12v system is because 12 volt has been the industry standard for sine wave inverters and due to this common voltage we can get a fantastic price on them.

10 of 14

Safety

BMS (Battery Management System)

Primary Objective: Balances the voltage in each individual cell group (prevents cell voltage deviation by charging the groups that exceed the mean)

Watchdog:

Thermal Cutoff Protection

Cell Block NTC, Ambient NTC, Inverter NTC

Short Circuit Protection

Over Current Protection (OCP)

Over Voltage Projection (OVP)

Exploded View

SPARKY

BMS

Battery Management

System

Now, to ensure user safety, the battery is equipped with a sophisticated battery management system (BMS). Its primary objective is to prevent any voltage deviation in each cell group by engaging a series of resistors that drain high voltages to the mean level. Secondly, the BMS serves as a protective fuse in the event of internal or external failures.

Strategically placed NTCs (Negative Temperature Coefficient thermistors) ontop of critical components of the battery continuously feed temperature data to the BMS. This allows the system to detect when a component, such as the cell block, is about to fail and will the BMS automatically disconnects the battery from the inverter, halting all operations. Preventing a catastrophic failure.

Moreover, in the unlikely event of an external source malfunctioning which closes short, the BMS promptly detects the issue and cuts off power before the battery has any chance of igniting.

11 of 14

Unlocking Value in the Battery Life Cycle

12 of 14

Bill of Materials

7.6V 34Ah Nissan Leaf Battery Cells $110 CA

(Quantity: 2) | $55 CA Per Piece

WaterProof Hard Shell Case $66 CA

(Quantity: 1) | $66 CA Per Piece | Direct from Supplier

500W Pure Sine Wave Inverter $29 CA

(Quantity: 1) | $24 CA Per Piece | Direct from Supplier

12V Battery Monitor (SoC Display) $ 3

(Quantity: 1) | $3 CA Per Piece | Direct from Supplier

110V/220V NEMA 5-15 Socket $ 5

(Quantity: 2) | $5 CA Per Piece | Direct from Supplier

Total: 213 CAD / 3050 TRY

13 of 14

Conclusion

SPARKY Is

Safety
Scalable
Cost Effective
Carbon Neutral
Electronically Simple

Top View

SPARKY

14 of 14

Thanks for Listening

ICAMES 2023

Simon Fraser University | Bogazici University