Battery Thermal Storage Assembly Using High-Heat-Capacity Plastic
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Solution Overview
Problem
Rechargeable lithium ion batteries generate heat during charging and discharging, which must be managed to prevent overheating, especially in sealed battery packs where traditional heat removal methods like metal heat sinks and forced convection are inefficient and can introduce contaminants, necessitating a more effective thermal management solution.
Innovation Solution
A battery assembly incorporating thermal storage devices made of thermoplastic materials with high specific heat capacity and thermal conductivity, which absorb and store heat generated by battery cells, maintaining a stable temperature by reducing heat transfer through the use of thermally conductive plastics and minimizing thermal resistance at the interface with battery cell walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional metal heat sinks are used to conduct heat away from batteries, then heat removal efficiency is improved, but device complexity and risk of contamination increase
Solution Approach 1:
The patent changes the material parameter from metal to thermally conductive plastic, maintaining thermal conductivity while eliminating the need for complex metal heat sink structures and contamination risks. The plastic material is formulated with specific thermal conductivity (0.1-4.0 W/(m·K)) to achieve effective heat removal without traditional metal heat sink complexity.
Solution Approach 2:
The patent uses composite plastic materials that combine thermal conductivity with structural properties. The thermally conductive plastic acts as both the structural housing and the thermal management medium, eliminating the need for separate metal heat sink components and reducing overall device complexity.
2Temperature
If phase change materials are used to absorb heat, then temperature stability is improved, but the material changes phase and loses structural integrity
Solution Approach 1:
The patent changes the thermal management mechanism from phase change to sensible heat storage in solid plastic. The plastic material remains in the solid phase throughout operation, maintaining structural integrity while absorbing heat through temperature increase within its solid state thermal capacity.
Solution Approach 2:
The patent uses a solid plastic material that can be replaced or regenerated. The thermal storage device itself is simple and can be disposed of or replaced when thermal performance degrades, rather than requiring complex phase change material systems.
3Temperature
If heat is continuously removed from batteries at the same rate it is generated, then temperature stability is improved, but energy efficiency decreases
Solution Approach 1:
The patent implements periodic thermal management where the solid plastic thermal storage device absorbs heat during high-demand discharge periods, then gradually releases stored heat during low-demand periods. This periodic action maintains temperature stability without continuous active cooling, improving energy efficiency.
Solution Approach 2:
The thermal storage device passively absorbs and stores heat generated by battery operation without requiring external power or active control systems. The system self-regulates temperature through the inherent thermal properties of the solid plastic material.
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 manages heat within the battery assembly, maintaining stable temperatures and preventing overheating by absorbing and storing heat, allowing for continuous operation without the need for extensive heat dissipation, thus enhancing reliability and reducing the risk of thermal shutdown.
Implementation Method 1
The thermal storage device is made of a solid material having a thermal conductivity of between about 0.1 and 4.0 W/(m·K)
Implementation Method 2
Other solutions employ a phase change material wrapped around the battery cells to slow temperature increase. In this case, the latent heat of melting of the phase change material absorbs heat energy from the battery cells without changing the temperature of the heat sink material.
Data Source
AI summary
A thermal storage device for batteries is provided. In some examples, the thermal storage device is provided for a battery pack that includes one or more rechargeable battery cells. In some examples, the lithium ion battery cells are used. The thermal storage device is in thermal contact with the battery cell. The thermal storage device is made of a material that absorbs heat that is given off by battery cells during discharge. In some examples, the thermal storage device is made of a plastic material. The material has a relatively low thermal conductivity but a relatively high specific heat capacity, allowing heat energy to be stored in the thermal storage device. The thermal storage device prevents the battery pack from overheating during use. The thermal storage device defines one or more cell receiving volumes. In some examples, an axially extending relief volume is provided.