Presentation on theme: "EV Safety David Kerzel Modular EV Power LLC Pompano Beach, Florida."— Presentation transcript:
EV Safety David Kerzel Modular EV Power LLC Pompano Beach, Florida
EV Safety TypeMass ProducedConversions
EV Safety TypeMass ProducedConversions LocationHomeWorkPublic
EV Safety TypeMass ProducedConversions LocationHomeWorkPublic WhoOwnerPublic First Responders
EV Safety TypeMass ProducedConversions LocationHomeWorkPublic WhoOwnerPublicFirst Responders ConcernElectricityFireAccidentsOther
EV Safety We are early adopters of this technology We need to use the technology safely We need to encourage others to use the technology safely We need to understand the Risks We need to be able to explain the facts to others
Change Much of the worry about EV’s relates to Change Many people don't want any change Others accept it as they see the benefits Some may have business to loose Some just enjoy being negative Simple factual responses and answers are best.
First Responders First responders worry about there safety In ICE vehicles they cut the battery cable In Ice vehicles there is no high voltage In Ice vehicles it is easy to tell if the engine is on Training and experience is what is needed. When Air bags were first used there was unfounded concern about them exploding in a fire.
Electricity Electricity is dangerous and needs respect. We have electricity in our homes and we are safe. It is safe because: There are codes and guide lines for construction Products are tested and listed UL or ETC for safe operation Building inspectors verify parts are used as intended.
Electricity The EV stores it electricity in a battery pack. The voltage is typically 120 volts DC to 400 Volts DC. The battery can store 10 to 40 KW-Hours of energy. That is a lot of energy. My home uses 5 KW-Hours of energy per day. My home could use 38 KW-Hours of energy per hour but it does not. One gallon of gasoline contains about 33 KW-Hours of energy. People feel safe with gasoline because it has been around for so long. There are gasoline car fires.
Electricity in the Car EV’s are electrically isolated form from the chassis and it is grounded Electricity must flow through a body. The isolation prevents this.
Battery in Production EV’s Man years of engineering, testing and Design Designed to be safe, long Life In a Package Touch Safe Containment Crash worthy Serviceable Battery Management Control Disconnecting means for service and first responders Standardized wire colors to identify high voltage
Battery in Production EV’s Designed to be safe, long Life In a Package Touch Safe Containment Crash worthy Serviceable Battery Management Control
Batteries in Conversions Goal is often get as many batteries in as possible Initial goals are often to be safe and long Life serviceable Is it really touch safe? Will the batteries and any fluids be contained? Is it crash worthy? Will it be serviceable?
Batteries in Conversions What is crash worthy? The Converter’s Guide to the Galaxy and EV Conversions The Converter’s Guide to the Galaxy and EV Conversions By Richard W. Marks, A complete book about how to plan a safe conversion Battery mounting needs to withstand forces 20 times the battery weight in the forward and side to side directions. Things will bend and plastic covers will move. Plan for shorts or damaged wiring. Batteries should never be in the cabin with the occupants Even though they may appear low cost Lead Acid and AGM have so much mass and spill potential they should not be used today.
Batteries in Conversions
Batteries and FIRE Any time there is lots of energy available fire is a possibility. Wiring failures Circuit failure Water or fluid failures Crash damage One leads to another
Batteries and FIRE The Volt Fires. Weeks after a Crash test the car burns The crash test caused the battery coolant to leak in the battery pack and got the electronics wet and the pack failed and burned. Coolant or liquids are not a problem with the 12V battery in present cars due to low voltage and chemistry. It is new technology and it would be great if every problem could be anticipated but it is the real world.
Batteries and FIRE Conversion Fires. Yes, there have been many conversion fires Neal Young’s LinkVolt project car. In the movie “Revenge of the Electric Car” Gadgets fire looks to focused at the battery pack. Most seem to happen in the night with unattended charging.
Batteries and FIRE Conversion Fires. Unattended charging and BMS often seem involved. These systems must have redundant safe guards to prevent over charging. They must take temperature into consideration and stop if a problem is detected. They must fail in the off state. My personal issue is poor quality BMS wiring. Telephone low voltage solid wire that can break or chafe leading to a serious problem with no warning. Ever notice automotive wires thick insulation?
Batteries and FIRE Why so much on Fires. Lithium ion batteries are safe at the rated current levels and at the rated temperatures. They do have organic solvents inside that are flammable at higher temperatures. The real problem is over charging. The Li+ suddenly changes from ions to metal when over charged. The metal can short out a cell and cause a hot spot. The pressure goes up and the battery vents or bursts. One hot cell heats the next. Li metal is very active and can separate water to H² and OH, generate heat and burn. Water may not put the fire out.
Batteries and FIRE What can we do to reduce the risk. Like production cars only use 70 or 80% of the pack capacity. This leaves a safety gap at the ends of the charge cycle. It also extends the number of cycles the batteries will provide. Recognize this as a serious problem and use the best construction and wiring around the battery pack. I would want a smoke detector in the garage even if I trusted the car!
J1772 SAE J1772:2010™ charging brings several levels of safety to charging and the electrical interface. There are extra costs with this extra safety There is also the advantage of a common compatible connector for most cars.
Level 1 Typically implemented as VAC 1440Watt-Hour At 200 Watts/mile so 1 hour of charge hour gives 6 miles Level 2 Typically implemented as VAC 5500 Watt-Hour At 200 Watts/mile so 1hour of charge hour gives 27 miles At 80 amps 1 hour of charge hour is 19,200 Watts giving 96 miles
Why are EVSE so expensive Safety Out in the weather Vandals Abuse like driven on Liability It’s new!
The Car Charger is in the car for level 1 and 2 All electrically isolated form from the chassis and it is grounded
J1772 Vehicle Inlet
Shrouded pin and sleeve design Separated Touch safe Protected from damage Starting to mate Interlocking protection Ground first Fully mated Full contact Long Interlocking path
EVSE The EVSE does not power the cable or connector until it is latched and the car requests power
J1772 Pilot Signal EVSE is UL listed and covered by NEC Article 625
Pilot Details When disconnected the Pilot is +12VDC Connecting Adds the diode and R2 which reduce the +12VDVC to +9VDC This starts the PWM signal, 1KHz, Positive PWM width represents current I = duty cycle X Amps, then changes. Close S2, +9/-12V changes to +6/-12 and contactor coil gets power and car gets power.
Proximity Tells the car it is connected. It is OK to charge Inhibit motion
Level 3 Fast DC Direct connection to the battery V2G possibilities
Level 3 Fast DC CHAdeMo is the most established Tokyo Electric Power CompanyTokyo Electric Power Company, Nissan, Mitsubishi and Fuji Heavy IndustriesNissanMitsubishiFuji Heavy Industries 500 VDC at 125 Amps
Level 3 Fast DC SAE J1772 Level 3 GMGM, Chrysler, Ford, Toyota, Honda, Nissan, and Tesla.ChryslerFordToyotaHondaNissanTesla Expected to be 600VDC at 200 Amps Combines the J1772 Level 1 & 2 connector with the Level 3
EMI and RFI Electric things do produce EMI and RFI Some people worry about it other don’t There are standards modern products Vehicles must comply to be safe Designs limit the emissions no to interfere with others or radio. Shielded wires Conversions emissions are likely higher.
Mechanical Issues Always use the hand brake Consider chocks Vehicle Weight Brakes Weight balance To much power
Electrical Issues Respect the battery pack Disconnect the pack before work Never work on electrical parts while charging Insulate tools Long sleeves and gloves make it safer. Never work alone
Charging Stations, EVSE Public or business locations Look it over for damage its outside Check the status Try to advise someone if it’s down Plug in Check that its functioning Unplug and move the car when done What about that ICE car? What about unmarked 120V outlets
Charging Stations, EVSE Place the cable to safe and obvious Put the cable back Concern and liability about people tripping on a cable in use or improperly stored
Charging Stations, EVSE Use them when you can to show people they are needed.