Pouch Capacitor-Assisted Battery Cell for Cold-Start Pulsed Power
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Solution Overview
Problem
Existing low voltage automotive battery systems face challenges in providing sufficient pulsed and continuous power at both warm and cold temperatures, especially in supporting emergency stop operations of autonomous vehicles, while maintaining high temperature durability and cranking current requirements.
Innovation Solution
A pouch-type capacitor-assisted battery cell design incorporating negative electrodes with graphite, positive electrodes with lithium iron phosphate and activated carbon, and a specific electrode arrangement to enhance thermal uniformity, along with a liquid electrolyte in a pouch enclosure, to improve power delivery and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional low voltage automotive battery systems are used, then the system can support basic vehicle accessory loads, but the system fails to provide sufficient pulsed power at both warm and cold temperatures for emergency stop operations and cranking current requirements
Solution Approach 1:
The patent employs a composite electrode structure combining lithium iron phosphate (LFP) particles with activated carbon (AC) matrix, creating a hybrid material system that integrates the high voltage stability of LFP with the high surface area and rapid electron transfer capabilities of activated carbon. This composite structure enables the electrode to deliver both sustained continuous power and high-intensity pulsed power across a wide temperature range, resolving the contradiction between power capability and temperature-dependent reliability.
Solution Approach 2:
The electrode design incorporates local quality variations through the distributed network of conductive carbon and activated carbon particles within the electrode matrix. Different regions of the electrode material provide different functional properties: LFP particles contribute to voltage stability and continuous power, while activated carbon regions provide high surface area for rapid charge transfer during pulsed operations. This spatial distribution of functional properties enables the electrode to simultaneously satisfy both continuous and pulsed power requirements under varying temperature conditions.
2Power
If the battery system uses lithium-ion battery cells to reduce weight and improve pulsed power density, then the pulsed power capability increases, but the thermal management complexity and high temperature durability challenges increase
Solution Approach 1:
The patent modifies key material parameters to achieve high pulsed power density while maintaining thermal stability. The activated carbon matrix provides high surface area (increasing reaction sites for rapid charge transfer), while the LFP particles maintain stable crystal structure at elevated temperatures. The electrolyte composition and electrode porosity are optimized to facilitate ion transport at various temperatures. These parameter optimizations enable the battery to deliver high pulsed power density without sacrificing high temperature durability.
3Speed
If the battery system is designed to meet cranking current requirements, then the instantaneous power delivery improves, but the continuous power delivery and thermal management capability deteriorate
Solution Approach 1:
The electrode is segmented into multiple functional components: LFP particles segmented throughout the matrix provide stable voltage and continuous power delivery capability, while activated carbon particles segmented throughout provide rapid electron transfer pathways for cranking current. This segmentation allows different regions to specialize in different temporal power delivery modes, with the overall electrode system capable of both instantaneous high-current delivery and sustained continuous power output.
Solution Approach 2:
The conductive carbon network and activated carbon matrix are pre-configured within the electrode structure to establish rapid electron transfer pathways before operation. This preliminary structural arrangement ensures that when cranking current is demanded, the electron transport infrastructure is already in place to immediately support high-rate charge transfer, enabling fast cranking current delivery without compromising the continuous power delivery capacity of the LFP particles.
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 design achieves excellent pulsed and continuous power capability at various temperatures, supports emergency stop operations, and provides high cranking current, ensuring reliable performance in automotive applications.
Implementation Method 1
second particulate electrode material including lithium iron phosphate (LFP) arranged on opposite sides of the second current collector, and a third tab, M ones of the P positive electrodes include a third current collector, third particulate electrode material including activated carbon (AC)
Implementation Method 2
along with a liquid electrolyte in a pouch enclosure, to improve power delivery and durability
Data Source
AI summary
A pouch-type, capacitor-assisted battery cell includes: N negative electrodes, where N is an integer greater than one, each of the N negative electrodes includes a first current collector, first particulate electrode material, and a first tab; P positive electrodes, where: P-M ones of the P positive electrodes include a second current collector, second particulate electrode material, and a second tab, M ones of the P positive electrodes include a third current collector, third particulate electrode material including activated carbon (AC) arranged on opposite sides of the third current collector, and a third tab, and P=N−1 and M=2; separators arranged between the N negative electrodes and the P positive electrodes; and a pouch enclosure surrounding the N negative electrodes, the P positive electrodes and the separators; where the M ones of the P positive electrodes are located approximately equidistant from a center of the P positive electrodes.