2019 Hyundai Kona

The 2019 Hyundai Kona is an electric vehicle produced from 2018 to 2021.

This is the long range 64kWh usable pack.

The 64kWh pack has five modules that are located under the floor in the main cabin with two stacked modules under the rear seats. There are 294 cells total configured as 98s 3p.

Note that the 2019 Hyundai Kona and Kia Niro share the same battery pack design. The difference is that the Hyundai Kona uses LG cells and the Kia Niro uses SK Innovation cells.

• Usable energy = 64 kWh (total = 67.5 kWh)
  • SoC Window = 94.8%
• Nominal Voltage = 356 V [4]
• Configuration = 98s 3p
• Nominal Capacity = 189.6 Ah
• Power = 170 kW_10s [4]

The battery pack voltage, usable energy and power were declared by Hyundai in their news release [4]. The battery pack voltage does not align with the cell specification and number of cells in series. However, the cell specification will be for a slightly higher discharge rate and hence lower nominal voltage.

Charging

• Fast charging power = 77 kW
• Time for fast charge = 44 minutes (10-80% SoC)

Physical Dimensions

• Pack Mass = 452 kg
  • Cell Mass = 259 kg
  • Pack-Cells = 193 kg
  • Cell to Pack Ratio = 57 %

The following service diagram shows the module, coolant system and battery enclosure.

Expanded Polypropylene (EPP) foam on the side of the modules filling the voids will have a number of possible functions:

• energy absorption for side impacts
• thermal insulation
• location for harnesses

All of these are possible functions, the primary function is probably impact energy absorption.

Cooling

The Kona uses cooling plates and a liquid coolant fluid. These plates cool the lower edges of the pouch cells that are arranged in 5 large modules and hence 5 cooling plates.

The two stacked modules at the rear of the pack appear to be fed from the two outer coolant plates in series.

The concern is that these two rear modules will see higher coolant temperatures than the 3 modules that run the length of the pack.

The two stacked rear modules are likely to age prematurely.

The cooling plates have expanded polystyrene insulating strips underneath, isolating them from the casing.

The cooling channels are close together, each is about 20x5mm internal CSA with a 10mm gap between each channel, so there is a lot of coolant area in the plate. They have a putty type thermal paste which engages with the stainless thermal plates between each pouch cell, so there’s really good thermal coupling over the surface of the cell.

Each module has 2 temperature sensors.

So although there’s a long serial loop for the coolant I wonder if the flow is reasonable there may be an acceptable temperature gradient?

Thanks to Ralph Hosier from RHEL.co.uk for the insight.

Metrics

• Pack Gravimetric Energy Density = 149.3 Wh/kg
  • Cell = 257 Wh/kg
• Gravimetric Power Density = 376 W_10s/kg

Cell

Vehicle recall in March 2021 due to folded anode occurring during production and possibility of it causing a fire [1].

References

1. Part 573 Safety Recall Report 21V-127, NHTSA
2. LG E63B Specification
3. Hyundai Kona Feature, Hyundai EU
4. Hyundai News Release, Hyundai