Research Experience for Teachers (2018-2019)
Lithium Ion Battery Testing
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Pre/Post Test: Pre/Post Test  |
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Keywords:
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The Big Idea (including global relevance) Electrical Energy Storage: Much of the world’s electrical energy is produced through the burning of fossil fuels including coal and natural gas. There is a growing societal shift away from the use of these conventional fuels over the desire for energy independence, and concerns about limited resources and global warming. The use of renewable energy sources like wind and solar are used to supplement conventional fuels, however wind and solar will not be able to completely replace conventional fuels since they are not able to provide a continuous supply. The wind is not always blowing and the sun is not always shining. In order for wind and solar to supply the full needed electrical energy, wind and solar must be used with energy storage systems. These energy storage systems must temporarily store the energy when generated and then used on demand. Lithium-ion batteries are currently one of the best options for electrical energy storage when using wind and solar and are already extensively used for personal electronics, power tools, and electric and hybrid cars. With the increasing use of lithium-ion batteries, the recycling and re-use of materials should be considered. Lithium-ion battery packs are composed of many individual cells, and a dead battery pack often has only up to 50% failed cells. The remaining cells often have more usable life and can be used to refurbish the battery pack or repurposed for other projects. |
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Essential Questions
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The Hook
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The Challenge The students will design a process to test individual lithium-ion cells to determine which cells have more usable life and which cells will need to be recycled. |
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Guiding Questions
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ACS (Real world applications; career connections; societal impact)
Electric energy storage is becoming a larger need within the transportation and power generation arenas with the rise of electric vehicles and renewable power generation using wind and solar. Large battery packs using individual lithium-ion cells are commonly used for electric cars, personal electronics, and temporary storage for solar and wind power generation. Larger battery packs have a limited life span, however since they are composed of individual cells, many of the individual cells are still functional and can be extracted and repurposed for extended life.
The use of materials which have limited supply and limited life span should involve careful consideration when they reach the end of their usable life. Recycling the material, or directly repurposing the material should be used whenever possible. This unit gives students the experience of finding ways to repurpose battery backs which were discarded and headed for recycling.
• The careers which are directly related to the challenge are electrical and chemical engineering. I will plan on discussing these areas of engineering within Activity #2 where students are introduced to the basics of battery chemistry and characteristics.
Misconceptions
- A battery cell is an ideal voltage source which is able to maintain a constant voltage regardless of output current.
- Electrons move through the battery from the positive to the negative terminal during discharge and from the positive to the negative terminal while charging.
Unit Lessons and Activities
- Lesson 1: Battery Basics – (3 days) Lesson 1 will focus on using the challenge based learning process to develop a project around the testing and reuse of used lithium-ion batteries. The lesson also includes both direct instruction and basic inquiry involving the basics of chemical batteries: safety, charging and discharging limits, voltage ranges, and series and parallel combinations of individual battery cells.
- Activity 1: Introduction to Batteries using CBL (2 days) – This activity will introduce the big idea, essential question, challenge and guiding questions.
- Activity 2: Battery University (1 day)
- Lesson 2: Modeling Non-Ideal Batteries, Testing and Construction– (8 days) Lesson 2 enables students to create a conceptual understanding and the ability to test non-ideal chemical batteries. The conceptual model involves the concepts of internal resistance and electromotive force. The Challenge for students will be to design an evaluative process for used lithium-ion batteries which does not compromise safety or future performance. The last part of the lesson uses the tested lithium ion cells to construct a small portable battery pack which can be charged and discharged through standard USB cables.
- Activity 3: Modeling Non-Ideal Batteries (3 days)
- Activity 4: Battery Evaluation Design. (5 days) – Students will design and test a process for evaluating used lithium-ion batteries
- Activity 5: Battery Pack Construction (2 days)
- Evidence of CBL: Lesson 1, Activity #1; and Lesson 2, Activity #4
- Evidence of EDP: Lesson 2, Activity #4
Additional Resources
Materials used in Challenge:
- Activity #1: Introduction to Batteries using CBL
- Disassembled laptops and/or power tool battery packs.
- Activity #2: Battery University
- D-Cell Batteries
- D-Cell Battery Holders
- Electric Multi-Meters
- Activity #3: Modeling Non-Ideal Batteries
- Electric Multi-Meters
- Voltage Sensors
- Current Sensors
- Power Resistors
- Alligator Clips
- Activity #4: Battery Evaluation Design
- Used lithium-ion battery packs – if you ask around enough you should be able to acquire used laptop or power tool batteries or they can be purchased in bulk from eBay
- Security Bit Set – this will be needed if you need to open used power tool batteries.
- Zanflare C4 Smart Charger / Tester – This will be used to initially charge the individual lithium-ion cells once removed from the battery back, before tested by students.
- 18650 Battery Cell Connectors - these are used to make electrical connections to the terminals of the individual lithium-ion cells.
- abcGoodefg 1Slotx3.7V 18650 Battery Holder Case Plastic Battery Storage Box with Pin 10 Pack (10 Pcs 1 Solts) – these are the cheapest option, but will require soldered connections for testing.
- Vruzend Solderless Connectors – these snap-on connectors use a bolt and nut to make the electrical connection to an external circuit without the need of soldering for testing or spot welding for making the final battery back.
- Activity #5: Battery Pack Construction
- 18650 Battery Cell Connectors (from Activity #4)
- Black Wire
- Red Wire
- Wire Cutters
- Wire Strippers
- Electrical Tape
- Soldering Iron
- Solder with Flux
- Heat Shrink Wrap
- Heat Gun for Shrink Wrap
- Micro USB Charging Protection Circuit – This allows the constructed lithium-ion battery pack to be charged with a micro USB charging cable. This provides charging protection, so the battery pack is not over charged.
- DC to DC Boost Converter with USB Output – This allows the battery pack to provide a constant 5V output so that it can charge anything that plugs into a standard USB port. This also provides discharge protection for the battery pack using a low voltage cutoff.
- USB to Micro USB Charging Cables – this is needed to charge the battery pack from a standard USB port.
- 10 Port USB Charging Hub – this will be used to charge all of the constructed battery packs.
- Lithium Solar Charger – this is used to charge a larger battery pack with a variable voltage source such as solar panels or a bicycle generator.