Brief Introduction of Lithium-ion Battery

Christina Du

What is Lithium-ion Battery?

https://www.youtube.com/watch?v=2PjyJhe7Q1g

Why Lithium-ion Battery?

Cell / Module / Pack

Vehicle Integration

Typical Classification-Materials

LiCoO2

1. Cell Chemistry : LiCoO2/Graphite

2. Application: Consumer electronics

3. Cell Voltage = 3.6V

4. Ad: High capacity, long cycle life.

5. Dis-ad: -low discharge rate; -Cobalt is scare and expensive.

Typical Classification-Materials

Typical Classification-Materials

1. Cell Chemistry : LiMn2O4/Graphite

2. Application: HEV/PHEV/EV

3. Cell Voltage = 3.8V

4. Ad: High safety, low cost.

5. Dis-ad: capacity fade at high temperature.

LiMn2O4

Typical Classification-Materials

1. Cell Chemistry : LiFePO4/Graphite

2. Application: HEV/PHEV/EV

3. Cell Voltage = 3.2V

4. Ad: high safety, low cost.

5. Dis-ad: -relatively low energy -poor low temperature performance

LiFePO4

Typical Classification-Materials

1. Cell Chemistry : NMC/Graphite

2. Application: HEV/PHEV/EV

3. Cell Voltage = 3.7V

4. Ad: -relatively high energy -long cycle life

5. Dis-ad: capacity fade at high temperature.

NMC1. Cell Chemistry : NCA/Graphite

2. Application: Power tools, BEV

3. Cell Voltage = 3.7V

4. Ad: high energy

5. Dis-ad: poor thermal stability.

NCA

Typical Classification-Materials

1. Cell Chemistry : NMC/LTO; LFP/LTO

2. Application: HEV

3. Cell Voltage = 2.1V / 1.7V

4. Ad: high charge & discharge rates

5. Dis-ad: - easy to swell - low energy density

LTO

Typical Classification-Package

Li-ion Cell Types

Liquid Li-ion cell- Liquid electrolyte

- Typically steel or aluminum (sometimes plastics)

Cylindrical

Prismatic

Polymer Li-ion cell- Gel electrolyte

- Typically aluminum pouch soft packing

Typical Classification-Power & Energy

How to define the battery type?

PE ratio

𝟐𝟓℃𝑯𝒊𝒈𝒉𝑯𝑷𝑷𝑪 ,𝟓𝟎% 𝑺𝑶𝑪 , 𝑨𝒗𝒆𝒓𝒂𝒈𝒆𝑷𝒐𝒘𝒆𝒓𝟐𝟓℃𝑯𝒊𝒈𝒉𝑯𝑷𝑷𝑪 ,𝟓𝟎% 𝑺𝑶𝑪 , 𝑨𝒗𝒆𝒓𝒂𝒈𝒆𝑬𝒏𝒆𝒓𝒈𝒚

Typical Testing Methods-HPPC Hybrid Pulse Power

Characterization

Typical Testing Methods-DST Dynamic Stress

Test

Typical Testing Methods-CL Calendar Life

Test

Typical Testing Methods-Cold Cranking

Cold Cranking Test

Typical Testing Methods- C-rate Multiple C-rate

Test

Fast Charge or Normal Charge

Lithium metal dendrites (short circuit hazard)

Fast charge could not happen frequently, otherwise it will result in battery degradation.

Normal charge

Fast charge

Overcharge & Overdischarge

OverchargeLi deposit on anode, Li-

dendrites formed

Cell resistance raise; cell temperature raise.

Electrolyte decomposition and

gasification

Overdischarge

Capacity loss

Cycle life shorten

Cell resistance increase

Vehicle Cooling System

Volt Liquid cooling

Nissan Leaf Natural cooling

Volvo S60L Liquid cooling

BYD Qin Natural cooling

Thermal Management System

liquidair

Common Selection Rules

Safety Specific Energy

Cycle Life Manufacturing Process