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Cells, Modules and Blocks

People often confuse Toyota modules with cells because they misunderstand the difference between the smallest unit (the cell) and the smallest replaceable unit (the module, in Toyota’s case).
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Think of a Toyota hybrid battery like an army, with different levels of organization: cells (soldiers), modules (squads), blocks (platoons), and the battery pack (the entire battalion). Each level plays a role in storing and delivering power efficiently.

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1. Battery Cells (The Soldiers – Smallest Unit)

A battery cell is the basic building block, like a single soldier in an army. In Toyota’s NiMH (Nickel-Metal Hydride) batteries, each cell produces 1.2V of power. However, a single cell isn’t enough to power the car—it needs to work as part of a larger unit.

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2. Battery Modules (The Squads – Smallest Replaceable Unit)

Since a single cell doesn’t provide enough power, Toyota groups multiple cells together into a module.

  • Each module contains 6, 8, or 12 cells (depending on the hybrid model).

  • In most Toyota hybrids, the module is the smallest serviceable unit, meaning individual cells cannot be replaced separately.
     

3. Battery Blocks (The Platoons – Smallest Monitorable Unit)

Toyota’s battery management system doesn’t monitor individual modules—instead, it monitors blocks.

  • A battery block is made up of two modules connected in series.

  • For example, in a Prius hybrid battery with 28 modules, there are 14 blocks (since each block consists of 2 modules).

  • The Hybrid Battery ECU (Electronic Control Unit) keeps track of the voltage at the block level to detect any weak or failing sections.
     

4. Battery Pack (The Battalion – The Full Power Source)

The battery pack is the complete system that powers the hybrid vehicle.

  • It contains multiple blocks working together to supply high voltage.

  • Most Toyota hybrids have a pack voltage of 200V to 245V, depending on the model.

  • The pack also includes a Battery Management System (BMS) and a cooling system to ensure everything runs efficiently.

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The Battery Pack (battalion) is the entire system that powers the car.

So, just like an army functions through different levels of organization, a Toyota hybrid battery delivers power through cells, modules, blocks, and the full pack working together!

Disclaimer

The information provided on this blog is based on the experiences and knowledge of its creators regarding Toyota and Lexus hybrid vehicles. While the content aims to offer helpful insights and guidance, it should not be considered professional advice or a guideline for performing any DIY or professional repairs and maintenance.

This blog and its creators are not responsible for any decisions or actions taken based on the information provided. Hybrid vehicles involve complex systems, including high-voltage components, and attempting DIY repairs or maintenance without proper expertise can be dangerous. Readers are advised to exercise caution, follow safety protocols, and consult certified professionals when necessary.

Additionally, the creators of this blog are continuously learning and improving their understanding of hybrid cars. As new information becomes available, efforts will be made to update and correct any inaccuracies. However, the content is not definitive, and readers are encouraged to verify facts, conduct independent research, and seek expert advice before making any decisions.

By using this site, users acknowledge that any actions taken based on its content are at their own risk. This blog serves as an informational resource, but ultimate responsibility lies with the individual.

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