TMS & Components
What does TMS stand for?
Thermal Management System.
What can happen to an EV battery when it gets very cold?
Its performance and range can decrease.
What is a coolant loop?
A system that circulates coolant to transfer heat.
Q: What is battery pre-conditioning?
Preparing the battery to reach a suitable temperature before driving or charging.
Complete the sentence: “The battery temperature was too high, ___ charging power was reduced.”
so / therefore.
Name two components of an EV thermal management system.
A coolant pump and a heat exchanger.
How can excessive battery temperature affect battery life?
It can increase battery degradation and reduce battery longevity.
What is a heat pump used for in an EV?
It transfers heat to heat or cool the vehicle or battery efficiently.
Why does an EV pre-condition its battery before fast charging?
To bring the battery to a suitable temperature for efficient and faster charging.
Complete: “The coolant level was low. As a result, …”
the thermal management system could not operate correctly / battery temperature increased.
What is the purpose of a chiller in an EV thermal management system?
It removes heat from the coolant to help cool the battery.
Explain how battery temperature can affect EV range.
Very high or very low temperatures can reduce battery efficiency and available energy, which can reduce range.
What is the difference between a coolant loop and a heat pump?
The coolant loop circulates coolant; the heat pump transfers heat between different areas of the system.
Explain pre-conditioning to a customer who does not understand technical terms.
The car warms or cools the battery before you drive or fast-charge, so the battery is at a good temperature and can work more efficiently.
A battery temperature sensor reports a value that is much higher than expected. Give two possible causes.
A faulty sensor, wiring problem, poor coolant circulation, overheating, or a cooling-system fault.
How can a coolant loop, heat pump and chiller work together to control battery temperature?
The coolant loop circulates coolant around the battery. The heat pump or chiller transfers heat into or out of the coolant to keep the battery at the correct temperature.
Why can an EV have less range in very cold weather?
Cold temperatures reduce battery efficiency and may increase energy consumption for heating, so the available range decreases.
Use TMS, coolant loop, heat pump and chiller to explain how an EV controls battery temperature.
“The TMS controls battery temperature. The coolant loop circulates coolant, while the heat pump and chiller transfer heat to keep the battery within its optimal temperature range.”
A customer wants to use a DC fast charger on a very cold morning. Why is pre-conditioning useful?
It warms the battery to a suitable temperature before charging, which can improve charging performance and reduce charging time.
A battery temperature sensor reports a temperature that is much higher than expected. What are two possible causes, and what should the technician check first?
Possible causes include a faulty temperature sensor, damaged wiring, poor coolant circulation, or an overheating problem. The technician should check the diagnostic data, sensor readings, wiring/connectors, and coolant circulation.
An EV battery becomes too hot during DC fast charging. Describe how the TMS should respond and name the components that may be involved.
Temperature sensors detect the increase. The TMS increases cooling through the coolant loop and may activate the chiller or other cooling components. If necessary, charging power is reduced to protect the battery.
Explain the relationship between battery temperature, performance, range and longevity.
Very low temperatures can reduce performance and range. Excessive temperatures can also reduce performance and accelerate battery degradation. Keeping the battery within its optimal temperature range improves performance, range and longevity.
Explain the function of a TMS, coolant loop, heat pump and chiller in one technical explanation.
“The TMS controls the battery's temperature. The coolant loop circulates coolant through the system. The heat pump transfers heat for heating or cooling, while the chiller removes heat from the coolant when additional cooling is required.”
Explain battery pre-conditioning to a customer in three simple sentences.
“The car prepares the battery before you drive or charge. It heats or cools the battery to the right temperature. This helps the battery work efficiently and can improve fast-charging performance.”
A vehicle arrives with reduced DC charging power. The diagnostic scan shows high battery temperature. Write a 3–4 sentence diagnostic report using cause-and-effect language.
The battery temperature was above the recommended operating range. As a result, the TMS reduced charging power to protect the battery. The high temperature may have been caused by insufficient coolant flow or a fault in the cooling system. Therefore, the coolant circuit and related components should be inspected.