Lithium Ion/Polymer Battery Assembly Design and Trends Lion Polym… · All lithium-ion/polymer...
Transcript of Lithium Ion/Polymer Battery Assembly Design and Trends Lion Polym… · All lithium-ion/polymer...
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Lithium Ion/Polymer
Battery Assembly
Design and Trends
Presented by Brion Munsey
Western Regional Sales Manager
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Cell Types
Safety Circuits
Charging
Storage
Shipping/RoHs
Qualifying Assemblers
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Cell Types: Cobalt based
Manganese (Spinel)
Nickel-Cobalt Manganese
Nickel-Cobalt Aluminum
Polymer
Lithium Iron Phosphate
New Developments: Capacity Improvements
Lower Costs
Hi Drain Cells
Safer Cells
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High energy density - potential for yet higher capacities.
Does not need prolonged priming when new. One
regular charge is all that's needed.
Relatively low self-discharge - self-discharge is less than half that of nickel-based batteries.
Low Maintenance - no periodic discharge is needed; there is no memory.
Specialty cells can provide very high current to
applications such as power tools.
Lithium Ion Advantages
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Requires protection circuit to maintain voltage and current within safe limits.
Can be subject to aging, even if not in use - storage in a cool place at 40% charge reduces the aging effect.
Transportation restrictions - shipment of larger quantities may be subject to regulatory control.
Expensive to manufacture – due to added safety and regulatory requirements.
Not fully mature - metals and chemicals are changing on a continuing basis.
Lithium Ion Limitations
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Lithium Cobalt Oxide LiCoO2
Voltage: 3.7/cell
Pro: High Capacity
Con: Moderate Drain Rate Capability Moderate Safety Moderate Life Span
Applications: Cell Phones, Laptops, Cameras
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Voltage: 3.7/cell
Pro: Safe High Power Long Life
Con: Lower Capacity
Applications: Power Tools, EV, Medical, Hobby
Lithium Manganese Oxide LiMn2O4
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Lithium Iron Phosphate LiFePO4
Voltage: 3.2/cell
Pro: Safe High Power Long Life Large Format Available
Con: Lower Capacity
Applications: Power Tools, EV, Medical, Hobby,
Back Up Power
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Lithium Nickel Manganese Cobalt Oxide
LiNiMnCoO2
Voltage: 3.7/cell
Pro: Safe High Power Long Life
Con: Lower Capacity
Applications: Power Tools, EV, Medical, Hobby
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Voltage: 3.7/cell
Pro: High Capacity High Power Long Life Span
Con: Higher Cost
Not as Safe as LiMn2O4 & LiFePO4
Applications: Portable and EV Smart Grid
Lithium Nickel Cobalt Aluminum Oxide
LiNiCoAlO2
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Pro: High Power Fast Charge (10C) Good Low Temp Performance Long Cycle Life (6000)
Con: Lower Cell Voltage (2.4)
Applications: XEV, Grid, Medical, Military, UPS
Lithium Titanate Li4Ti5O12
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Voltage: 3.7/cell
Pro: Flexible Packaging Thin Low Cost Lightweight
Con: Less Durable Can Swell
Applications: Mobile, Medical, Military, EV
Lithium-Ion Polymer
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Typical Energy Densities of Rechargeable Battery Chemistries
Lithium-cobalt has the highest specific energy Manganese and phosphate are superior
in terms of power and thermal stability and cycle life.
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Energy Density Improvements and Cost Reduction for Lithium Ion
Lithium cells and batteries have made great progress over the last 20 years in terms of gains in energy density and
decreases in cost.
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Series: Up to four cells/groups in series (14.4V to14.8V) standard.
More than four cells custom requiring cell balancing.
Issues with 5S to 10S Cell Strings Cell balancing required
Extra components and custom design increase cost and development time.
FIFO (stock rotation) of cells Important practice
Cells lose capacity permanently if stored too long
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Overcharge Protection
Limit the charge voltage
Over-discharge Protection
Designed to cut off the current path if the battery is discharged below the manufacturer's recommended voltage
Over-current Protection
Discharge is stopped when output terminals are shorted
Resettable on PCBA and one time device as backup
Temperature Sensing
Via Thermistor
Disconnects the charge if the cell temperature approaches 90°C (194°F)
Safety Circuit Features
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Always use a CC/CV charger designed specifically for use with
your particular Li-ion or Li-Poly battery
Lower charge voltage can increase cycle life at the expense of capacity
Charging
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Batteries should be stored at room temperature at about 30%
to 50% of capacity. Batteries should be charged about once a year to prevent over discharge if not being used
Storage
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The life expectancy of batteries depends heavily on how the batteries are used
Different cells models are designed for specific benefits such as high capacity, high power, or long cycle life
Performance
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Testing and Transportation Requirements
All lithium and lithium ion/polymer cells and batteries
must pass the following UN Tests prior to being transported:
Test 1: Altitude Simulation
Test 2: Extreme temperature changes
Test 3: Vibration
Test 4: Shock
Test 5: External Short Circuit
Test 6: Impact
Test 7: Overcharge
Test 8: Forced Discharge
Shipping
All lithium-ion/polymer batteries must be tested and ship in accordance with the rules outlined in U.S. Hazardous Materials Regulations 49 CFR sub section 173.185 for lithium batteries and cells and/or meet the requirements for shipping according to the IATA Dangerous Good Regulations when applicable regardless of lithium content or Watt/Hour rating.
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Packaging, marking, and shipping documentation requirements for shipments of lithium and lithium ion cells and batteries
Boxes must be marked appropriately
Shipments must be accompanied by proper documentation
Boxes must be able to pass drop test (must be certified)
Boxes may not exceed 30 kg gross mass
Shipping
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RoHs
House of Batteries is fully committed to meeting the requirements of the European Union (RoHS) Directive.
The RoHS directive specifically excludes cells & batteries.
Legislation mandates specific recovery (recycling) programs for batteries and battery assemblies. Any potentially harmful waste stream (WEEE) is avoided.
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Inexpensive, poorly designed, and cheaply built batteries are a source of trouble.
Product and corporate reputation is compromised when
problems occur in the field
Public safety is threatened when poorly designed and built batteries malfunction to the point of presenting a hazard
Product returns increase and extra demand is placed on customer service
Many major manufacturers including Sony, Apple, Nikon, and Disney have had recalls on lithium rechargeable batteries due to quality issues
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Qualified Cells: Avoid use of inexpensive, substandard
cells
Is assembler certified by manufacturer?
Safety Circuit:
Avoid use of substandard components on circuit (counterfeit)
Back up with passives
Do not use circuit as primary source of discharge termination
Packaging:
Plastic enclosure best. Careful layout in soft packs can be safe
Soft packs should not be user replaceable
Pack Design Best Practices
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Checklist to Qualify
Assembler:
ISO Certified?
Quality Department?
Large Engineering Staff?
Extensive Test Equipment?
Hazmat Shipper?