How to

How to safely open a high-voltage battery pack

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Opening a high-voltage battery pack is a delicate and potentially hazardous process – and getting it wrong can have serious consequences.

Watch as our Delphi expert, Matt, walks you through how to safely and correctly open a high-voltage battery pack. He covers the key steps, including how to:

Prepare your work area and select the appropriate PPE
Identify different type of battery seals – rubber gasket vs. mastic
Remove the outer bolts and access the battery lid
Handle components carefully to avoid damaging internal parts
Use depth control methods when cutting through mastic seals

Batteries How to Distributors Shop Owners Technicians 1 min read

Why would I need to open a high-voltage battery pack?

Common reasons include diagnosing a coolant leak, replacing a faulty cell or module, or inspecting internal components for damage.

Do I need to wear safety gear when opening a high-voltage battery?

Absolutely! You should wear an arc flash suit – including high-voltage gloves and an arc flash visor – to protect against potential electrical hazards.

What are the different type of battery seals, and how do they affect the process?

Battery packs are typically sealed with either a rubber gasket or a mastic bond. Rubber gaskets are easier to remove, while mastic seals require careful cutting to get through to the internal components.

How can I safely cut through a mastic seal?

To avoid cutting into internal components, you can mark your blade with a temporary depth stop. As an extra precaution, you can also drill a physical depth stop into your blade.

What is the risk if I damage the components while opening the pack?

Battery internals are sensitive and high-voltage, which means even minor damage can lead to performance issues, short circuits, or safety hazards. That’s why proper technique and extreme caution are essential.