Bi-Directional Coolant Flow in Modular Battery Packs
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Solution Overview
Problem
Existing battery packs in electric vehicles face challenges such as uneven temperature distribution leading to capacity fade and impedance growth, limited space utilization, and potential thermal runaway events causing venting issues and safety hazards, particularly in long-haul commercial vehicles.
Innovation Solution
A modular and scalable battery pack design featuring multi-layer battery stacks with integrated thermal management devices, compressive frames, and vent isolation mechanisms to balance temperature, optimize space, and mitigate thermal runaway events, incorporating centralized or distributed heating and cooling systems with integrated sensors for monitoring and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-direction coolant flow system is used in battery packs, then the cooling system is simple in design, but temperature distribution becomes uneven causing capacity fade and impedance growth
Solution Approach 1:
The patent implements a bi-directional coolant flow system where the flow direction can be dynamically reversed through valve control. This allows the system to adaptively manage temperature distribution across battery cells by alternating flow directions, preventing hot spots and ensuring uniform cooling without requiring complex multi-zone cooling infrastructure.
Solution Approach 2:
The system employs periodic reversal of coolant flow direction through controlled valve operation. By cycling the flow direction at appropriate intervals, the system periodically redistributes thermal energy across different battery cell regions, preventing sustained overheating in any single area while maintaining relatively simple cooling hardware.
2Ease of manufacture
If traditional battery pack designs are used, then manufacturing is straightforward, but space utilization is limited and energy density is reduced
Solution Approach 1:
The patent implements multi-layer battery stack configurations where battery cells are arranged in nested vertical layers. This nesting approach maximizes the use of available pack volume by stacking cells vertically rather than using single-layer horizontal arrangements, significantly increasing energy density while maintaining straightforward assembly procedures through standardized stacking sequences.
Solution Approach 2:
The system transitions from traditional single-layer horizontal battery arrangements to multi-layer vertical stacking configurations. This dimensional change in spatial arrangement allows the battery pack to utilize vertical space more effectively, increasing volumetric energy density while preserving ease of manufacture through modular stack assembly.
3Stress or pressure
If battery cells are allowed to vent during thermal runaway, then pressure relief is achieved, but vented matter can cause chain reactions and safety hazards
Solution Approach 1:
The patent extracts and isolates the venting function from the main battery cell structure by providing dedicated vent paths that channel vented matter away from adjacent cells. This separation prevents hot gas and debris from one cell from directly impacting neighboring cells, reducing the risk of thermal runaway propagation while maintaining necessary pressure relief capabilities.
Solution Approach 2:
The system introduces vent isolation mechanisms as intermediary elements between battery cells during thermal runaway events. These intermediaries capture and redirect vented matter, preventing direct contact between hot gas/debris from one cell and adjacent cells, thereby mediating the thermal runaway process to prevent chain reactions while maintaining pressure relief.
4Device complexity
If fixed battery pack configurations are used, then design is simplified, but adaptability to different vehicle packaging spaces is limited
Solution Approach 1:
The patent divides the battery pack into modular, scalable segments that can be independently configured. The multi-layer battery stacks are designed as discrete modules that can be stacked in different quantities and arrangements, allowing the overall battery pack configuration to be adapted to various vehicle packaging spaces while maintaining simplified individual module design.
Solution Approach 2:
The system employs universal multi-layer battery stack modules that can serve different energy capacity requirements through simple stacking variations. The same basic module design can be scaled by adding or removing layers to match different vehicle packaging constraints, providing adaptability across multiple applications without requiring fundamentally different designs for each configuration.
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
Enhances energy density, improves battery life by balancing temperatures, optimizes space utilization, and reduces maintenance downtime by allowing modular scalability and efficient thermal management, while providing safety through vent isolation and detection systems.
Implementation Method 1
battery cells located on an upstream side of the flow of the heat exchange media can have a lower temperature than other battery cells in the battery pack, while batteries on the downstream side of the flow can have a higher temperature
Implementation Method 2
flow of the heat exchange media
Implementation Method 3
The thermal management system may include valves or other devices for periodically reversing a direction of flow of the heat transfer medium to assist in balancing a temperature between battery cells
Data Source
AI summary
A battery pack includes battery cells arranged in an array to form a battery module layer. Multiple layers are vertically stacked with thermal management devices, such as active heat exchangers in the form of battery cold plates, above and below each layer to form a multi-layer battery stack that may be held in compression by a battery pack frame. The multi-layer battery stack and battery pack frame are surrounded by a battery enclosure, which has flat sealing surfaces to ensure robust sealing. The battery pack is associated with a thermal management system for cooling and heating the battery cells of the battery pack. The battery thermal management system provides cooling and heating by alternating cooling flow directions to achieve uniform temperature distribution. The battery pack may also include a vent detection sensor and vent isolators to detect and mitigate effects of a battery thermal runaway event. Multiple battery packs of a common form factor can be combined in parallel in different arrangements for different vehicles to optimize electric vehicle range, performance, and weight distribution. The battery system can be, charged, discharged, controlled, and thermally managed either by a centralized system or distributed system.