Nissan Leaf teardown (Part 1)
Benchmarking systems and components for EV
On December 12, 2011, benchmarking was conducted in which Nissan's volume production electric vehicle, the Nissan Leaf EV, was disassembled and all its systems and components exposed. Benchmarking, organized by the Next-generation Automobile Support Center of the Saitama Industrial Development Corporation, was performed by the students of the Saitama Institute of Automotive Technology located in Ina, Kita Adachi-gun, Saitama Prefecture.
All parts and components having something to do with EV systems were separated from the vehicle and disassembled into individual units and components. Benchmarking did not involve further disassembly of removed parts or removal of sections that had nothing to do with EV systems, such as the interior equipment.
This report contains description of systems and parts in the order they were disassembled.
Nissan Leaf specifications
|Model name:||Nissan ZAA-ZE0|
|Size:||Overall length 4,445 × Width 1,770 × Height 1,545mm, Wheelbase 2,700mm|
|Weight:||Vehicle weight: 1,520kg, Gross vehicle weight: 1,795kg|
|Performances:||JC08-mode AC power consumption: 124Wh/km, JC08-mode cruising range: 200km/charge|
Main parts and their suppliers
|EV system parts||Power motor (3-phase AC synchronous motor, maximum output 80kW, maximum torque 280N･m) EM61 type||In-house supply by Nissan Motor's Yokohama Plant||Motor room|
|Inverter (IGBT x 6)||In-house supply by Nissan Motor /Calsonic Kansei||Motor room|
|DC-DC converter (doubles as a junction box)||Denso||Motor room|
|Power transmission system (reduction gear, reduction ratio: 7.937, without gear-shifting) model: RE1F61A||Aichi Machine Industry||Motor room|
|Lithium-ion battery module (total voltage: 360V, capacity 24kWh, output 90kW or higher)||AESC Automotive Energy Supply||Underfloor|
|BMS (Battery Management System)||Calsonic Kansei||In Li-ion battery module|
|Collision detection system||Panasonic||In Li-ion battery module|
|Onboard charger (input voltage: 100VAC~264VAC, output: 3.3kW maximum)||Nichicon||Cargo room|
|Noise filter (charging noise suppressor)||-||Cargo room|
|Auxiliary devices other than EV systems||A/C electric compressor||Panasonic||Cargo room|
|PTC heater (hot water 350V, 4.0kW, 5.0kW in cold areas)||Eberspaecher (Germany)||Motor room|
|Water pump for heaters||Nitto Denko||Motor room|
|Proximity warning system||Panasonic||Motor room|
|Capacitor (electrically-controlled brake backup power unit, power supply when 12V battery goes low)||Panasonic||Cargo room|
|ECU for electric parking brake||Advics||Cargo room|
|Electric parking brake, actuator (fitted to transmission)||Denso||Cargo room|
Nissan Leaf EV system diagram and sequence of disassembly
Disassembly work was performed in the order shown below:
- ① Motor room - Inverter and charging port removal
- ② Motor room - Drive unit (power unit + drivetrain) removal
- ③ Motor room - DC-DC converter removal
- ④ Motor room - Auxiliary systems removal
- ⑤ Li-ion battery module - Battery stack (protective case, bay) and battery pack removal
- ⑥ Cargo room - Onboard charger and electrical component removal
- ⑦ Overall - Removal of parts
Removal work took place in three blocks as shown above: 1) steps ① to ④ in the motor room (equivalent to the engine room on engine-powered vehicles), 2) step ⑤ involving the battery unit under the floor, and 3) step ⑥ involving the charger and auxiliary systems in the cargo room.
* Click on the photo for a larger image.
|Disassembly and removal work in progress|
|Drive units (electric motor, power transmission system, drive-shafts etc.) being lowered from the vehicle|
Views of the motor room
① Motor room - Inverter and charging port removal
|Inverter||Inverter (view from rear)|
|Inverter supplied by Calsonic Kansei (view from front). Nissan's in-house supplied inverters are also used.
The bulge for cooling water hose connection is seen in the front left.
|Inverter (view from rear)|
② Motor room - Drive unit removal
Main components of the power unit
|Front (when mounted) of the power motor||Shaft connector of the power transmission system|
|The motor type "EM61" engraved in the front of the power motor (as mounted).||Shaft connector of the power transmission system with the drive-shaft removed (vehicle left).
The power transmission system (RE1F61A supplied by Aichi Machine Industry) does not have a gear-shifting mechanism. It is a reduction gear with the reduction ratio of 7.937 and is designed to suppress torque loss during the high-speed revolution of the motor.
|Electric parking brake and actuator||A/C electric compressor|
|Electric parking brake and actuator (mounted over the power transmission system), supplied by Denso.
The electric parking brake ECU (supplied by Denso) is located in the cargo room.
|A/C electric compressor (supplied by Panasonic).
Mounted by direct coupling over the power motor.
On engine-powered vehicles, the compressor is driven by the engine. On Nissan Leaf EV, the compressor is driven by high-voltage power supplied by the DC-DC converter rather than by the power motor.
③ Motor room - DC-DC converter removal
|View from lower front of the vehicle
with the drive unit removed
|DC-DC converter (passenger compartment side)|
|View from the lower front of the vehicle with the drive unit removed reveals how the DC-DC converter is mounted and the high-voltage cable routed. The power units such as the power motor, power transmission system and the inverter are mounted via the drivetrain members. The DC-DC converter is mounted to and protected by a sturdy member frame for greater crash safety.
The DC-DC converter (supplied by Denso) is also called a DC-DC junction box as it serves as a gateway of high-voltage cables.
The cable at the center of the photo running to the back (vehicle rear) is for the battery module connection. The cable running from right to the back (vehicle rear) is for the connection from the DC-DC converter and the normal charging port to the onboard charger in the cargo room.
The two cables running from the front of the DC-DC converter in the right front of the photo are connected to the quick charging port. The cable running from the center front to right is for power supply to the PTC heater.
|View from vehicle rear (passenger compartment side) of the removed converter.
The high-voltage coupler at the lower center of the photo is the connection harness to the lithium-ion battery module.
The fixture in the upper right is the connection bulge for the converter cooling water hose.
④ Motor room - Auxiliary system removal
|Water pump for the heater, PTC heater||PTC heater|
|The heater water pump (round part at upper center) and the PTC heater (box-like part underneath) are shown as mounted (view from vehicle right).||PTC heater removed from the vehicle (view from top as mounted).
The PTC heater with 350V and 4.0kW ratings (5.0kW in cold areas) is manufactured by Eberspaecher, a German corporation.
On engine-powered vehicles, the engine's cooling water is used as the heat source of the heater. On Nissan Leaf EV, the high-voltage power supply from the DC-DC converter is used to heat the water using the PTC element. The hot water is circulated by the water pump.
|Proximity warning system|
|The proximity warning system (supplied by Panasonic) audible alerts pedestrians that the vehicle is approaching (as mounted).|
⑤ Lithium-ion battery module removal
|Inner view of the battery stack|
|Inner view of the battery stack (view from vehicle front when mounted).
The entire battery module weighs 294kg and measures 1,188 (W) x 1,570 (L) x 265mm (H). The orange-colored coupler in the foreground is the receptacle for the high-voltage cable from the DC-DC converter.
The flat-stowed battery packs in the right and left sides in the foreground are the front module stacks, 12 of them in each side. The vertically stowed battery packs in the background are the rear module stacks (24 battery packs). The 48 packs in total provide the rated 360V output. The battery packs are supplied by AESC Automotive Energy Supply.
The black module in the center foreground (between the flat-stowed packs) is the collision detection system (supplied by Panasonic). The system interrupts high-voltage power when it detects collision.
The white box in back of the collision detection system contains a service plug of the SD/SW (service disconnect switch). When the power switch in the driver's seat cannot be turned off or when the high-voltage power interruption fuse cannot be accessed as the bonnet hood in the motor room cannot be unlocked after an accident or for other reasons, the SD/SW is accessible when the floor in the vehicle rear section is opened. The high-voltage circuit will be shut down when the plug is removed.
|Collision detection system|
|Collision detection system, covered for protection, with battery stack mounted.
(View from the vehicle front when mounted)
|Collision detection system (removed from battery stack and uncovered).
A pair of detectors is used (supplied by Panasonic).
(View from the vehicle front when mounted
|BMS battery management system||BMS mounting position viewed from rear|
|BMS battery management system (supplied by Calsonic Kansei).
BMS manages and controls charge/discharge of the lithium-ion battery.
BMS is mounted to the left of the rear module stack (shown in the right-hand photo with the BMS removed).
|BMS mounting position viewed from rear when mounted to the rear module stack (fitted using the bracket at far-left of the battery pack in the foreground).|
|Couplers removed from battery packs|
|Couplers removed from battery packs.
Couplers for rear module stack (top) and couplers for front module stack (bottom).
⑥ Cargo room - Onboard charger and electric component removal
|Onboard charger in the cargo room
behind the rear seat
|The onboard charger (supplied by Nichicon) in the cargo room behind the rear seat and the noise filter that suppresses charging noise in the foreground (vehicle front to the left with the rear seatback, and the cargo room to the right).
The commercial AC power fed from the normal charging port is rectified from AC to DC by the onboard charger and sent on to the DC-DC converter in the motor room.
|Capacitor (electrically-controlled brake backup power unit, supplied by Panasonic) supplies necessary auxiliary power for the electric brake in the event the 12V battery power goes low. The capacitor has no direct involvement with the EV control systems.|
|ECU for electric parking brake||Equipment in the cargo room|
|ECU for the electric parking brake (supplied by Advics) is mounted in lower front of the capacitor. The electric parking brake is mounted over the transmission in the motor room.||Equipment in the cargo room removed together with the bracket.
Shown are, from left to right, the onboard charger, noise filter and capacitor (electrically-controlled brake backup power unit).
⑦ Overall - Removal of parts
|Future service pros of the Saitama Institute of Automotive Technology
that performed benchmarking overlooking the removed parts
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