Electric Work Vehicle Battery Pack Cooling and Charging Alignment
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Solution Overview
Problem
Electric work vehicles face challenges in maintaining uniform battery module temperatures due to foreign matter clogging cooling air passages, and existing designs compromise vehicle balance and battery space, while contactless charging systems require optimal coil alignment to avoid ground obstacles.
Innovation Solution
A sealed battery case with horizontal partitioning to separate internal spaces, a circulation fan for uniform temperature, and strategic motor and battery pack placement to maintain balance, along with a contactless charging system featuring a two-stage primary coil structure and adjustable elevation mechanism to ensure optimal coil alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is taken in from the surroundings, then battery cooling is achieved, but foreign matter such as cut grass or straw mixes in with the cooling air causing clogging of the cooling air passage
Solution Approach 1:
The battery pack is divided into multiple battery modules arranged in a matrix pattern, with separate cooling passages for each module. This segmentation allows independent cooling of each module while preventing foreign matter from blocking entire cooling systems. The cooling passages are further divided into first cooling passages for front modules and second cooling passages for rear modules.
Solution Approach 2:
A circulation fan is introduced as an intermediary device to actively circulate cooling air through the battery modules. The fan creates controlled airflow that pushes foreign matter away from the cooling passages while maintaining adequate cooling, rather than relying on passive natural convection that allows foreign matter to accumulate.
2Quantity of substance
If multiple battery modules are included in the battery pack, then power capacity is increased, but it becomes difficult to make the temperatures of the battery modules uniform
Solution Approach 1:
The battery pack is segmented into multiple independent modules arranged in a matrix, with dedicated cooling passages for each module. This segmentation allows precise temperature control of individual modules while maintaining high overall capacity. The matrix arrangement ensures uniform heat distribution across all modules.
Solution Approach 2:
Different cooling strategies are applied to different regions of the battery pack. Front modules have first cooling passages while rear modules have second cooling passages, allowing localized optimization of cooling for each module based on its specific thermal characteristics and position within the pack.
3Device complexity
If the left and right pair of motors are arranged inside the vehicle body frame with the battery between them, then vehicle structure is compact, but a large-sized battery cannot be used and vehicle balance deteriorates
Solution Approach 1:
The battery modules are arranged in a matrix pattern extending in both the vehicle front-rear direction and lateral direction, rather than simply lengthening the battery in one direction. This two-dimensional arrangement allows large battery capacity while maintaining compact overall dimensions and proper vehicle balance.
Solution Approach 2:
The battery is divided into multiple modules arranged in a matrix with four rows and multiple columns. This segmentation allows the battery to occupy optimal space within the vehicle frame while maintaining proper weight distribution and vehicle balance, rather than using a single large battery that would compromise vehicle dynamics.
4Extent of automation
If the secondary coil is arranged between the front and rear wheels on the lower surface, then contactless charging is enabled, but coil misalignment with ground obstacles causes charging instability
Solution Approach 1:
The primary coil unit is designed with movable and adjustable characteristics, allowing dynamic positioning and angle adjustment to maintain optimal alignment with the secondary coil despite ground obstacles or vehicle position variations. This dynamic adjustment capability ensures stable contactless charging transmission.
Solution Approach 2:
The contactless charging system uses electromagnetic field coupling between primary and secondary coils positioned at different heights and orientations. By utilizing the third dimension (vertical spacing and angular orientation) rather than relying solely on horizontal alignment, the system achieves stable charging transmission even when ground obstacles are present.
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
The solution effectively prevents foreign matter entry, maintains uniform battery module temperatures, improves vehicle balance, and ensures stable contactless charging by preventing coil misalignment, enhancing the operational efficiency and stability of electric work vehicles.
Implementation Method 1
a circulation fan configured to create a circulated air flow that circulates through the first space, the second space, the third space and the fourth space
Implementation Method 2
a secondary coil that electromagnetically couples with the primary coil; a charging circuit portion configured to rectify power from the secondary coil and supply the rectified power to the battery pack
Data Source
AI summary
An electric work vehicle includes: a battery pack that is arranged between a left rear wheel arranged outside of a left frame and a right rear wheel arranged outside of a right frame, the front end of the battery pack being located forward of an axle center of a rear wheel unit; a left motor that is arranged above the battery pack, in the periphery of the left rear wheel, receives a supply of power from the battery pack, and transmits rotational power to the left rear wheel; and a right motor that is arranged above the battery pack, in the periphery of the right rear wheel, receives a supply of power from the battery pack, and transmits rotational power to the right rear wheel.