BYD Atto 3 battery dismantle P2 - contactor block

Summary

In this detailed teardown of a Byd Blade battery pack, the presenter investigates the internal components, including the contact block, BMS, and contactors. Despite initially searching for a fuse, no fuse is found within the pack itself, though a 350V fuse is discovered in one of the contactors. The presenter also explores the interlock circuit and cooling channels, revealing insights into the design, such as unimplemented interlock circuits and the intricacies of the refrigerant cooling system. Throughout, the presenter highlights the complexity and design choices within the pack.

Takeaways

• 😀 The BYD blade battery pack lacks a visible fuse, leading to the assumption that it may be located inside another component of the system.
• 😀 The battery pack features both low and high voltage connections, including a pre-charge resistor and relay for system management.
• 😀 The disassembly reveals a lack of interlock system implementation despite having the physical ability for one, raising questions about safety design choices.
• 😀 A shunt is used to measure current flow in and out of the battery, and the BMS has various resistors covered in hot glue for isolation detection.
• 😀 The high voltage positive terminal is connected via a bus bar to the BMS, which includes voltage sensors for monitoring pack performance.
• 😀 The contactors, crucial for controlling high voltage current flow, are rated for 250A and 800V, with identical designs for both positive and negative sides.
• 😀 The battery pack design is somewhat complicated by unnecessary complexity, including differing mounting logs for seemingly identical components.
• 😀 The low voltage connectors used in the pack are small and low profile, lacking an interlock mechanism to ensure safety during disassembly.
• 😀 The cooling channels in the battery pack are designed to carry refrigerant through small plates with tiny channels, optimizing heat management in the system.
• 😀 The user expresses concerns over the overall design, such as the decision not to implement interlock circuits and the lack of fuse protection in certain areas of the battery pack.

Q & A

What is the speaker investigating in the video?

The speaker is investigating the internal components of a BYD Blade battery pack, specifically looking for a fuse, examining the battery management system (BMS), and exploring the structure of the cooling channels and contactors.

Did the speaker find any fuse in the battery pack?

Initially, the speaker could not find a fuse in the main body of the battery pack. However, later in the video, a fuse is found in one of the contactor packages, rated for 350A and 800V.

What role do the pre-charge resistor and relay play in the battery pack?

The pre-charge resistor and relay are part of the circuit responsible for gradually charging the capacitors before high current is supplied to the system, preventing sudden current spikes and ensuring the safety of the electrical components.

What is the purpose of the battery management system (BMS) mentioned in the video?

The BMS monitors and manages the battery pack's voltage, state of charge, temperature, and overall health. It ensures safe operation by detecting faults and providing feedback for voltage regulation and pre-charging, among other tasks.

What did the speaker find unusual about the interlock circuit?

The speaker points out that while the battery connector has the potential for an interlock circuit with shorting pins, it does not appear to be implemented. This could mean that the battery pack lacks a feature that would disable it if the connector is unplugged, which could pose safety concerns.

Why does the speaker mention the design of the contactor mounting logs?

The speaker mentions that the contactor mounting logs have different designs, which he believes is a poor design decision. This adds unnecessary complexity to the assembly line, potentially increasing production costs and time.

What are the characteristics of the contactors discussed in the video?

The contactors are 250A 12VDC, with copper terminals on top. The speaker also mentions that the contactors are part of the power distribution system in the battery pack, with one positive and one negative contactor.

How does the speaker feel about the battery pack’s construction and design?

While the speaker notes that the battery pack is compact and features a lot of components crammed into a small space, he expresses concerns about some design decisions. Specifically, the lack of an interlock system and the complex contactor mounting logs are areas he finds inefficient.

What is the function of the cooling channels inside the battery pack?

The cooling channels are designed to circulate refrigerant across the battery pack. The speaker highlights that these channels help maintain the temperature of the battery during operation, preventing overheating and ensuring optimal performance.

What does the speaker suggest about the QR codes on the components?

The speaker mentions that the components, such as connectors, have QR codes, which likely provide additional information or specifications about the parts. He seems to appreciate the efficiency of this design for easy tracking and identification.