High Voltage Batteries

NFPA ELECTRIC VEHICLE SAFETY FOR EMERGENCY RESPONDERS

Module III:

Vehicle Systems and Safety Features

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NFPA ELECTRIC VEHICLE SAFETY FOR EMERGENCY RESPONDERS Module III: Vehicle Systems and SafetyFeatures

Module III Objectives Terminal Objective Describe the operation of P/HEV and EV systems. Enabling Objectives ● ● ● ●

Define terms related to P/HEV and EV systems. Compare and contrast P/HEV’s and EV’s. List major components of P/HEV systems. List major components of EV systems.

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Definitions HEV Hybrid Electric Vehicle

A vehicle that has both an internal combustion engine (ICE) and electric motor(s).

PHEV

Plug-In Hybrid Electric Vehicle A vehicle that has both an ICE and electric motors, and can recharge its batteries to full charge from an external electric power source.

EV

Electric Vehicle A vehicle which uses only electric motor(s) for propulsion. 3-3

Video

Vehicle Types

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Hybrid Electric (HEV)

All hybrids use batteries and electric motors to reduce demand on the internal combustion engine (ICE). ● Allows better fuel economy.

Toyota Prius

● ICE can shut down when not needed.

● Full Hybrids can drive short distances on electric power only (silent movement hazard). ● For response purposes, treat all hybrids the same.

Honda Civic Hybrid 3-5

Plug-In Hybrid Electric (PHEV) A hybrid vehicle that allows the battery to be charged via an external power source. • Increases battery charge

2012 Ford Escape

• Increases range • Reduces dependence on the gasoline engine. 2012 Toyota Prius 3-6

Electric Vehicle • •

Electric motors are the only means of propulsion. Vehicle must be charged by an external power source.

Nissan Leaf 3-7

Extended Range Electric Vehicle •

Electric motors provide the propulsion.

•

When battery is low, gasoline generator provides the electricity for the motor. •

Chevrolet Volt

For emergency response, treat as a PHEV with… • • • •

a gasoline engine high voltage battery electric propulsion possible external power. 3-8

HEV / PHEV / EV VEHICLE COMPONENTS

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Standard Components

Internal Combustion Engine

12 Volt DC Battery

12 VDC battery can be located in various locations around vehicle. Common Locations: · Trunk / Cargo compartment · Under hood

Less Common Locations: · Front wheel well · Under 2nd Row seats 3-10

Video

12 VDC and High Voltage Batteries

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High Voltage Batteries Battery Types

NiMH Nickel Metal Hydride

Lithium Ion Various Materials

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High Voltage Batteries

Nickel Metal Hydride (NiMH) Battery ● Most common battery in existing hybrids. ● Less common in newer vehicles.

● Electrolyte is alkaline.

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High Voltage Batteries

Lithium Ion (Li-Ion) Battery ● Most common in electric vehicles. ● Will be used more in future hybrids. ● Many different chemical variations. ● Different from Li-Ion batteries in home electronics. 3-14

Video

High Voltage Battery Construction

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High Voltage Batteries

Small Cells in Series ● High voltage batteries are made of many small, lowvoltage cells.

● Small cells wired in series to multiply voltage. ● Ex: Four 1.5 VDC batteries in series equals 6 VDC.

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High Voltage Batteries

Location of Batteries in HEVs, PHEVs

Generally located in rear of vehicle.

Under 2nd row seating in most SUVs and trucks, in trunk/ cargo area in most sedans. 3-17

High Voltage Batteries

Location of Batteries in EVs

● EV Batteries are larger and of higher voltage than P/HEV batteries. ● Usually located on the underside of the vehicle.

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High Voltage Batteries

Service Disconnects ● Recommendations for use and required safety equipment vary by manufacturer. Consult appropriate ERG before using service disconnect. ● Located on the battery. ● Cuts off the battery from the high voltage system. Service disconnect will be addressed later in course. 3-19

Inverter/ Converter

Located under hood

● Found in vehicles using AC drive motors. ● Converts DC from HV Battery to AC to run motor. ● Converts AC from regenerative braking back to DC to charge HV Battery. 3-20

Inverter/ Converter Located under hood

Dangerous to penetrate cover with tools.

●

Capacitors inside unit can store voltage for a period of time.

●

If damaged, capable of rapid energy discharge that can cause severe injuries. 3-21

DC/DC Converter

DC-DC Converter (APM) for Chevrolet Volt

● Takes the place of the alternator. ● Converts DC from high voltage battery to 12 VDC to run vehicle’s low voltage systems. ● In some models the DC/DC converter is housed in the inverter/converter module. 3-22

Video

High Voltage Battery Relay

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EV/ HEV Cabling

Color coded to SAE voltage levels ● Low Voltage: 60 Volts Orange

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Medium/High Voltage Cabling

Medium and high voltage should both be considered highly dangerous.

For the purposes of this program, treat blue cables the same as high voltage orange. 3-25

High Voltage Cabling

Location ● Between the HV battery, HV components, and the electric motor. ● Typically routed along the underside of the vehicle and under hood.

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High Voltage Cabling Construction/Fault Protection If a cable is compromised or damaged, the system is designed to detect the damage and shut down. For safety, ALL high voltage cable should be considered energized during response operations. 3-27

Electric Motors P/HEVs •

Provide propulsion in some models.

•

Start and stop the ICE when not needed.

•

Recharge HV battery through regenerative braking and ICE.

EVs •

Provide propulsion and recharge HV battery through regenerative braking. 3-28

Regenerative Braking A process used to capture energy from braking and help recharge the high voltage battery. ● During braking, wheels turn the electric motor, making it act as a generator and produce electricity. ● Electricity routed to HV battery to increase charge. Can damage HV system if towed in overhaul. 3-29

Safety Systems

P/HEVs and EVs have safety systems designed to automatically shut down the high voltage systems in the event of: ● Crash Impact ● Airbag Deployment

● Cabling damage ● Short Circuits Always treat HV systems as energized for maximum safety. 3-30

Charging Ports •

Used to connect a charging cord to the vehicle.

•

The charging components reside on the vehicle.

•

The charging unit is an interface between the power supply and the vehicle. 3-31

Charging Stations

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Charging Stations

Level I

Level II

120 VAC 8-16 hours

240 VAC 3-8 hours

DC Quick Charge 480 VDC 20-30 min.

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Level 1 Charging Station

Level I 120 VAC 8-16 hours

● Utilizes 120VAC power. ● Uses standard household plug. ● Slowest rate of the three levels. ● Can accompany vehicle to charge it anywhere.

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Level II Charging Station

Level II 240 VAC 3-8 hours

● Utilizes 240VAC power. ● Can be a fixed installation or portable unit.

● Faster than Level I systems. Typically 3-8 hours depending on the size of the battery.

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J1772 Plug and Receptacle ● SAE standardized for Level I and II charging. ● Multi-pin charging/ communication link between charger and vehicle. ● Conducts current. ● Relays charge status. ● Shuts down charging when battery “full.” ● Prevents vehicle from moving when pluggedin. 3-36

DC Quick Charge Station DC Quick Charge 480 VDC 20-30 min.

● Currently provides 480VDC directly to the battery. ● New standards being developed, so this may change. ● Fastest charging system. ● Due to wiring requirements, availability, and expense, will likely be in commercial sites only. 3-37

Activity 3.1 P/HEV, EV Components You will be shown a series of slides, each with a picture of a component of a P/HEV or EV.

You will be given a few moments to discuss and decide on the name of the component and its function. Be prepared to share your answer with the class. 3-38

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Component

High Voltage Battery Function

The electrical storage system that provides power for vehicle systems.

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Component

High Voltage Cabling Function

Wiring used to carry electric current from the high voltage battery to the electrical motor.

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Component

Inverter / Converter Function

Devices which convert DC from the high voltage battery to AC to drive the motor. May also house DC-DC converter to step down high voltage DC to 12VDC to run standard vehicle systems. 3-44

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Component

Charging Ports Function

Electrical connections on a vehicle for connecting the high voltage battery to a charging source.

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Component

Manual Service Disconnect Function

Cuts off the battery from the high voltage system. Refer to Manufacturer ERG before use!

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Component

J1772 Connector Function

Multi-pin communication link between charger and vehicle.

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Activity 3.1

End of Activity

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Module Summary

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There are several different types of P/HEVs and EVs.

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Each one has specific components related to its electrical identify.

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Familiarity with the types, components and differences will facilitate emergency operations.

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