EV Power Supply Unit Layout Between Floor Cross Members
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Solution Overview
Problem
In electric vehicles with a rear-wheel drive vehicle body structure, the power supply unit is often positioned above the drive unit, making it vulnerable to damage during a rear collision as it is not protected by the rear suspension cross member, leading to a need for effective protective measures.
Innovation Solution
The power supply unit is arranged between upper and lower floor cross members that form a strong, integrated structure extending in the left-right direction, with the upper rear floor cross member providing additional strength to minimize deformation during a collision, and a unit cover is used to further protect the power supply unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the power supply unit is positioned above the drive unit near the rear suspension cross member, then the power supply unit is closer to the drive unit for easier connection, but the power supply unit becomes vulnerable to damage during rear collision as it is not protected by the rear suspension cross member
Solution Approach 1:
A protective structure (intermediary element) is introduced between the power supply unit and the collision impact. This protective structure includes reinforcement members positioned at the rear of the power supply unit to absorb and distribute collision forces, preventing direct impact damage to the power supply unit while maintaining its operational position above the drive unit for easy connection.
2Reliability
If the power supply unit is moved away from the rear suspension cross member to a safer position, then protection against collision damage is improved, but the connection between power supply unit and drive unit becomes more complex
Solution Approach 1:
The protective structure utilizes the vertical dimension by positioning reinforcement members above and around the power supply unit, rather than moving the power supply unit horizontally to a less optimal location. This maintains the compact vertical arrangement for simple wiring while adding protective elements in the vertical and rearward directions to shield against collision impacts.
3Reliability
If reinforcement structure is added to protect the power supply unit, then protection against collision damage is improved, but the overall vehicle weight increases
Solution Approach 1:
Rather than adding a comprehensive reinforcement structure throughout the vehicle, the invention applies localized reinforcement members specifically positioned at the rear of the power supply unit where collision impacts are most likely to occur. This targeted approach provides necessary protection while minimizing the addition of unnecessary weight to other parts of the vehicle.
Data Source
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AI summary
A total of four anchor points (5fl, 5fr, 5rl, and 5rr) are provided at front positions and rear positions of a left side member and a right side member (31 and 3r) provided on a floor (2). A drive motor (9), an inverter (10), and a transaxle (11), which serve as a drive unit (8), are mounted on the rear suspension cross member (4) supportively suspended from the respective anchor points. A junction box (21), a charger (22), and a DC-AC inverter (23), which serve as a power supply unit (20), are attached to the upper side of the floor (2). The junction box (21) relays electric power to supply it to the inverter (10). On the upper surface of the floor (2), an upper front floor cross member (16) is provided between the anchor points at the front position, and an upper rear floor cross member (17) is provided between the anchor points at the rear position. The power supply unit (20) is disposed between the members (16, 17).