Task Force 9: Communication and Messaging Wayne McKenzie William Joel Sanchez Task Force Leaders

Background Project Concern: The automotive application and use of a REESS, such as Lithium-ion battery based system, imposes certain safety risks to the operators and occupants of these vehicles, which are different than that of vehicles using only an internal combustion engine. Potential Safety Risk: Thermal runaway of the battery pack(s), which in some cases may result in fire or explosion. Project Scope: This research focuses on the safe management of an automotive REESS, i.e. its BMS and any electronic failures associated with it.

Project Goals and Scope Identify diagnostic and prognostic elements based on a comprehensive HARA of automotive REESS, specifically BMS functionality Determine information and messaging needs for operators and responders Write report that informs potential agency regulatory decisions Scope: Focus on safe management of an automotive REESS; i.e., its Battery Management System (BMS) and any electronic failures associated with it.

Project Objectives Delineate the hazards and their severity levels pertaining to the functional safety of automotive REESS controls, and identify safety requirements and constraints of BMS functionality Define system diagnostics, prognostics, and data logging Identify safety-critical information needs and effective methods to communicate this information to operators Address safety-related instructions and training needs for operators

Safety Concept Battery Management Controls: Measurement & protection of an automotive REESS, specifically the BMS and its interactions with other vehicle systems. Fail-Safe Response to Faulted Conditions Diagnostics/Prognostics Sensor Validity/Integrity Cell Voltage Cell Temperature Cell Balancing

Refinement of Analytical Scope REESS HV DC Bus Battery Pack Box & Seal Power Distribution Unit HV DC Bus Battery Pack Current Sensor Controls/Data LV DC Battery Management System (BMS) Controller HVIL Controls/Data CAN Bus OVERRIDING QUESTION: CAN THE STUFF IN THE BOX HANDLE ANY FAILURE INSIDE OR OUTSIDE THE BOX OBJECTIVE 1, TASKS 2 & 3 Communication Protocol Load Mgmt. Coolant Regen Mgmt. Vehicle Ground Charger Mgmt. Thermal Mgmt. Crash Detection

Automotive REESS System Description System Function Battery Pack Battery Management System Controller Power Distribution Unit System Function Stores electrical energy received from the charger or the vehicle Delivers energy to the vehicle systems Communicates with other vehicle module for proper vehicle functions Maintains safe vehicle operation

Battery Pack Description: Function: Sealed vented box Battery Pack Box & Seal Description: Sealed vented box Includes the battery modules, voltage sensors, cell voltage balancers, temperature sensors, condensation sensors, and ground fault detection circuitry Function: Stores electrical energy Delivers electrical energy Communicates cell status and isolation status Vent Cell Voltage Balancer Battery Cells Interconnects Battery Cells Cell Temp & Voltage Sensor Battery Cells Thermal Control Ground Fault Detection Battery Cells Battery Cells Condensation Sensor

Battery System Management Controller Description: Algorithms including State of Charge (SOC), State of Health (SOH), Diagnostics and Prognostics Communication Data Storage Safety Controls Function: Manages the energy in and out of the battery pack based on the SOC Acts on safety related requests from other vehicle systems Maintains the safety of the REESS

Power Distribution Unit Description: Main contactor Pre-charge contactor Relays and fuses Function: Controls connection between the battery pack and the High Voltage bus Ensures that the system power limits are respected

REESS External Interfaces OBJECTIVE 1

Scope of External Interfaces Analysis must consider external vehicle interfaces in terms of their impact on the safe operation of the REESS REESS must tolerate external failures and maintain a safe state OBJECTIVE 1

Diagnostic Trouble Codes Breakdown of hybrid power related to sample vehicle used 64% are related to the BMS (Brown & Orange sections) The Motor Controller (17%) and Charging System (11%) also prominent

Communications and Messaging Identify safety-critical information needs of owners and operators Describe effective means to communicate this information Describe barriers to effective communication and opportunities to remove them OBJECTIVE 3 TASKS 4 & 5

HEV/PHEV Status Indications System Status Charge State Low Charge Discharge Rate/Range BMW Mini E (BEV) Chevrolet Volt (PHEV) Fisker Karma (BEV+) Nissan Leaf (BEV) Tesla Roadster (BEV) (Regen Off) Toyota Prius (PHEV) OBJECTIVE 3 & 4

HEV/PHEV Malfunction Indications High Temp. 12V Fault REESS Fault Low Power Hazard /Other BMW Mini E (BEV) Chevrolet Volt (PHEV) Fisker Karma (BEV+) Nissan Leaf (BEV) Tesla Roadster (BEV) Toyota Prius (PHEV) OBJECTIVE 3 & 4

Questions