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High Voltage Distributionlink

Last updated: December 11, 2024

Overviewlink

This document focuses on the distribution of high voltage power among all HV components. Each high voltage component that is not directly used for HV distribution is detailed in other Theory of Operation documents.

The HV distribution architecture is influence by the powertrain configuration of the vehicle.

  • All configurations have the high voltage (HV) battery located in the chassis of the vehicle, between the 4 wheels of the car.

  • All Wheel Drive configuration has one front drive and one rear drive unit:

    • The front drive unit is located on the front subframe, between each front wheel.
    • The rear drive unit is located on the rear subframe, between each rear wheel.

  • Long Range and Standard Range RWD have a single drive unit located on the rear subframe, between each rear wheel.

For cabin and powertrain thermal heating / cooling , the HV system uses a heat pump. The HV system does not use a PTC heater (dedicated cabin heater), nor does it use a coolant battery heater. The HV system uses the heat pump to generate heat in the cabin and uses waste heat mode in the drive inverter, along with the heat pump to generate heat for the HV battery. For more details, refer to the section 'High Voltage Battery Thermal Management' in the Structural High Voltage Battery Theory of Operation.

The HV distribution design minimizes complexity, cost, and weight, with most connections consolidated within the HV battery and no separate HV connection components. The HV system includes the following components:

  • High voltage battery serves as the primary energy source for the vehicle.
  • Drive inverter(s) featuring waste heat mode, which heats the coolant and eliminates the need for a dedicated coolant heater component.
  • The Power Conversion System (PCS), located in the HV battery ancillary bay, which supports
  • DCDC conversions
  • LV to HV conversion for precharging the DC link bus before closing pack-contactors.
  • HV to LV conversion once contactors are closed to power the LV bus and manage LV battery state of charge.
  • AC to DC conversion for charging vehicle on AC power.
  • Cabin heating, ventilation, air conditioning (HVAC) system.
  • High Voltage Devices to manage high voltage distribution
  • Battery pack contactors manage the energy transfer from the HV battery to the DC link, supplying power to other high voltage components.
  • Fast charge contactors used to facilitate direct current charging.
  • Pyro disconnects to interrupt the HV loop when necessary
  • Shunts to measure current flow
  • Charge port assembly and charging harness for charging.

The illustration below provides a general overview of how the HV is distributed from the HV battery to all HV components, which creates the powertrain of the vehicle.

1. Charge port
2. Rear drive unit
3. Structural HV battery
4. Front drive unit (if equipped)
5. Heat pump compressor
HV Distribution Overview (Structural HV battery)

Most of the HV connections and branching are located inside the ancillary bay of the HV battery.

Location of High Voltage Componentslink

Location of High Voltage Batterylink

The HV battery is located between the rear and front subframes of the vehicle. The high voltage battery is mounted to the chassis of the vehicle, from underneath. This gives easy access to removal and installation from the bottom of the vehicle and gives the vehicle exceptional performance due to the lower center of gravity.

The HV battery is a structural HV battery. It is designed to be part of the vehicle body and carries structural properties for the chassis and body of the vehicle. The structural HV battery enclosure is integrated with the Body-in-White and provides front crash backup structure as well as interior seat mounts. The structural HV battery not only provides rigidity to the chassis for vehicle dynamics and crash response, but it also acts as the floor of the vehicle. The seats, carpet, center console, and other interior trim is mounted directly onto the structural HV battery.

The ancillary bay of the HV battery, which contains most of the HV devices of the HV battery, is located at the top rear of the HV battery on top of the modules. For more details, refer to the Structural High Voltage Battery Theory of Operation.
1. Structural HV battery
Structural HV Battery Location

The structural HV battery being part of the chassis means that without the structural HV battery, the vehicle body has a hole in the middle. See rendering below:
Model Y Body without Structural HV Battery Installed

The rendering below shows what the structural HV battery looks like, along with the vehicle's wheels to show location and proportions.
1. Structural HV battery
Structural HV Battery Between the Vehicle's Wheels

Location of Drive Unitslink

For Long Range/Dual Motor configurations, the rear drive unit is located in the rear subframe between the two rear wheels and the front drive unit is located in the front subframe between the two front wheels.

For Rear Wheel Drive (RWD) configurations (both Standard Range and Long Range), a single drive unit is mounted on the rear subframe, between the two rear wheels.

See the Drive Unit Theory of Operation for more details.
1. Rear drive unit
2. Front drive unit (Dual Motor configuration only)
Drive Unit Locations

Location of HV A/C Compressorlink

The HV A/C compressor is located between the firewall and the front trunk of the vehicle. The location of the heat pump compressor is behind the firewall for both the structural and non-structural HV battery vehicles. However, the firewall is located in different places in each variant.
1. AC heat pump compressor
Heat Pump Compressor Location

Location of Power Conversion Systemlink

The functions of AC charging and DCDC conversions are handled by the Power Conversion System (PCS). There is no dedicated AC charger or DCDC device in the vehicle.

The PCS (highlighted in blue) is located on the ancillary bay of the HV battery. For more details, refer to the Structural High Voltage Battery Theory of Operation.
1. PCS
Location of the PCS

High Voltage Build Up in the High Voltage Batterylink

High voltage is generated in the cell-arraysand distributed to the ancillary bay. The high voltage has to go through the pack-contactors to be able to energize the ancillary bay. More information on the pack-contactors is available in the Structural High Voltage Battery Theory of Operation. The high voltage in the ancillary bay is directly distributed to the shunt, pyrotechnic fuse disconnect, rear drive unit, cabin heater, and the HV A/C compressor. The diagram below helps visualize those connections within the HV battery and the ancillary bay.
1. Charge port
2. Charge port busbar
3. Three-phase connector (for non-North American markets)
4. Charge inlet HV connector
5. Rear drive unit
6. Rear drive unit HV harness
7. Ancillary bay
8. Structural HV battery
9. Front drive unit HV harness
10. Front drive unit
11. Heat pump compressor
HV Distribution Internal to the Pack

The PCS has a short connection to the high voltage, enabling current to flow in both directions: from PCS to DC link/HV battery during AC charging, and vice versa for 12V power support.

High Voltage Battery and High Voltage Component Interfaceslink

Although the PCS is not used when fast charging, it is connected to the DC link of the HV battery for the following functions:

  • Precharging the DC link but to pack voltage before closing contactors.
  • Stepping down high voltage from the HV battery to lower voltage to support the low voltage bus of the vehicle.

For more details, see Structural High Voltage Battery Theory of Operation.

The DC side of the PCS DC is connected as follows to the HV battery DC link:

The HV positive terminal of the PCS is connected to the positive DC link busbar, which is supplied by the positive pack-contactor. A 63A fuse is installed between the PCS HV connection and the busbar to provide overcurrent protection. The PCS HV negative connection is made via a cable that is bolted to the main DC link negative busbar using a round terminal, which in turn connects to the negative pack-contactor. The negative link from the DC link to the PCS is not fused, unlike the positive link.
1. Most negative terminal coming from cell array #1 and bolted to the battery side of the negative contactor
2. DC link terminal of the negative contactor
3. Main DC link negative busbar (highlighted in light blue and sits below the positive busbar)
4. Front drive unit negative terminal
5. Rear drive unit negative terminal
6. Negative terminal of ancillary connector (to HV A/C compressor)
7. Fast charge contactor negative terminal (DC link side)
8. Negative terminal of fast charge (FC) contactor connector
9. Most positive terminal coming from cell array #4 and bolted to the battery side of the positive contactor
10. DC link terminal of positive contactor
11. Rear drive unit positive terminal
12. Positive terminal of ancillary connector (to HV A/C compressor)
13. Front drive unit positive terminal
14. FC contactor positive terminal (DC link side)
15. Positive terminal of FC contactor connector
16. HV terminal from cell array #2 connecting to intermediate busbar with bolted joint
17. HV terminal from cell array #3 connecting to intermediate busbar with bolted joint
18. Pyro-disconnect and shunt between two intermediate busbars
HV Distribution Internal to the Pack

Note

The main DC link busbar for negative and positive are stacked on top of each other with an insulator between. Use the image above to help distinguish between the two.

AC Input to Power Conversion Systemlink

The PCS converts AC input from wall power through the charge port to DC voltage when charging the HV battery.

1. PCS
2. AC input to the PCS
3. Harness for AC input to PCS
4. Connection of PCS AC input 1 to charge port connector busbar
5. Connection of PCS AC input 2 to charge port connector busbar
6. Fast charge contactors
7. Connector to charge port harness
8. three-phase AC input Connector for EMEA and APAC
Connection of PCS to AC Input

Front Drive Unit and HV A/C Compressorlink

The front drive unit and HV A/C compressor are both located in the front of the vehicle, between the firewall and the front trunk (or frunk).

The structural HV battery features distinct HV routing, with dedicated harnesses for the front drive unit and HV A/C compressor that are routed along the battery's side. The HV A/C compressor harness runs on right side of the battery and the front drive unit on the left side. The side sills offer protection against low severity impact, but a high severity impact may result in damage to either the HV A/C compressor or front drive unit HV harness.

The image below gives a visual representation of the routing and connectors. For more details on the connectors at the front drive unit, refer to the Drive Units document.

1. Heat pump compressor HV harness
2. Front drive unit HV harness routed along structural HV battery
3. Rear drive unit HV harness
4. Charge port busbar
5. Heat pump compressor harness
6. Front drive unit harness

High Voltage Battery to Rear Drive Unitlink

The HV routing for the rear drive unit starts from the high voltage connector at the rear of the ancillary bay. The harness is dedicated to the rear drive unit and is composed of two HV cables. The harness is short in length to rapidly reach the drive unit. For more details, refer to the Drive Units Theory of Operation.
1. Rear drive unit HV connector at rear of structural HV battery
2. Rear drive unit HV harness
3. Rear drive unit HV connector at rear inverter
4. HV A/C compressor HV connector at rear of structural HV battery
5. HV A/C compressor HV harness
6. HV A/C compressor HV connector at compressor
Drive Unit HV Connections and HV Harnesses

Charge Port Connectionslink

The high voltage routing for the charger port starts from the high voltage connector at the rear of the HV battery. From there, refer to the section on Alternating Current (AC) and Direct Current (DC) connection to Power Conversion System (PCS) internally to the HV battery.
1. HV busbar joint point to ancillary bay
2. HV busbar joint point to charge port
Charge Port HV Connections
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