Electric Work Vehicle Battery Layout for Compact Cooling
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Solution Overview
Problem
Existing electric vehicles, particularly electric tractors, face challenges in efficiently packaging and cooling high-capacity battery systems while maintaining compactness and operational efficiency.
Innovation Solution
The design incorporates a power distribution unit (PDU) with separate housings for positive and negative rails, layered battery strings, and an evaporator between them, along with an air cooling system that utilizes multiple evaporator coils and ducts to efficiently cool battery modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If battery modules are arranged in a compact configuration to increase power capacity, then the vehicle's power capacity is improved, but the cooling efficiency deteriorates due to reduced space for cooling systems
Solution Approach 1:
The battery system is divided into multiple battery strings (first battery string, second battery string, etc.) with each string containing series-connected battery modules. This segmentation allows independent cooling paths for each string while maintaining compact overall packaging, resolving the contradiction between high power density and cooling efficiency.
Solution Approach 2:
The patent positions PDU housings on opposite sides of the vehicle centerline (left-right dimension) rather than stacking them vertically or placing them sequentially in the front-rear direction. This lateral distribution creates three-dimensional space utilization that accommodates both high-capacity battery arrangement and evaporator cooling systems without compromising either power capacity or cooling efficiency.
2Device complexity
If PDU housings are integrated into a single unit to reduce complexity, then device complexity is reduced, but accessibility for maintenance and repair deteriorates
Solution Approach 1:
The PDU is segmented into separate first PDU housing and second PDU housing units, each containing specific contactors and rails. This segmentation reduces overall system complexity by modularizing the design while simultaneously improving maintenance accessibility, as each housing can be independently accessed and serviced without disassembling the entire PDU assembly.
Solution Approach 2:
The battery housing serves as an intermediary structure that houses battery strings and provides mounting locations for PDU components. This intermediary arrangement allows PDUs to be positioned optimally for both structural integration and maintenance accessibility, with service plugs and contactors arranged for easy technician access during repair operations.
3Power
If battery strings are arranged in parallel to increase capacity, then the power capacity is improved, but the space requirement deteriorates
Solution Approach 1:
Battery strings are arranged in a three-dimensional configuration utilizing vertical stacking (up-down direction) and lateral positioning (left-right direction) rather than simple linear extension. This multi-dimensional arrangement increases power capacity by adding more battery strings without proportionally increasing the footprint area, as strings are layered and distributed across available vehicle space.
Solution Approach 2:
The patent implements a nested arrangement where battery strings are positioned within the battery housing structure that also accommodates cooling ducts and evaporators. The PDU housings are nested adjacent to the battery housing, and service plugs are positioned within accessible regions of the battery assembly, creating a compact nested configuration that maximizes power capacity within limited space.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for compact and efficient packaging of battery modules, enhancing the vehicle's power capacity and cooling efficiency, thereby improving the overall performance and reliability of electric tractors.
Implementation Method 1
an evaporator between them, along with an air cooling system that utilizes multiple evaporator coils and ducts to efficiently cool battery modules
Data Source
AI summary
An electric work vehicle includes a power distribution unit (PDU), a plurality of battery strings, and a battery housing to house the plurality of battery strings. Each of the plurality of battery strings includes a plurality of battery modules connected in series, the PDU includes a first PDU housing to house a positive rail and a second PDU housing to house a negative rail, each of the first PDU housing and the second PDU housing are separate and spaced away from the battery housing, the first PDU housing is located on a first side of a centerline of the electric work vehicle that extends in a front-rear direction of the electric work vehicle, and the second PDU housing is located on a second side of the centerline of the electric work vehicle opposite to the first side of the centerline of the electric work vehicle.