Rolled High-Voltage Battery Pack With Internal Series Cell Connections
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Solution Overview
Problem
Current lithium-ion batteries face limitations in energy and power densities, safety issues due to dendrite formation, and inefficiencies in cathode materials, while sodium-ion batteries exhibit lower specific energies and rate capabilities, necessitating high-energy density batteries that are safe and resistant to dendrite formation.
Innovation Solution
A high-voltage alkali battery design comprising multiple unit cells connected in series, with a laminated and rolled structure, using conductive materials, solid electrolytes, and flexible electrolytes to prevent dendrite formation, and housed in a single protective casing, eliminating external connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used as anode material to achieve high energy density, then theoretical capacity increases to 3,860 mAh/g, but safety problems occur due to dendrite formation during recharge cycles
Solution Approach 1:
The patent extracts the harmful dendrite formation process by introducing a protective coating layer on the lithium metal anode. This coating acts as a barrier that prevents dendrite growth while allowing lithium ion transport, thus maintaining high energy density while improving safety and cycle stability.
Solution Approach 2:
The patent employs composite material structures by combining lithium metal with protective coating materials (such as solid electrolyte interphase layers or artificial protective films). This composite approach enables the system to achieve both high capacity from lithium metal and enhanced safety from the protective coating, resolving the contradiction between energy density and reliability.
2Reliability
If graphite-based anodes are used to improve safety, then dendrite formation is reduced, but specific capacity decreases to 372 mAh/g and recharge time increases to 7 hours
Solution Approach 1:
The patent applies local quality by using different anode materials in different regions or contexts. Specifically, it employs lithium metal with protective coating in applications requiring high energy density and fast charging, while maintaining safety through the localized protective layer, thus achieving both high productivity and reliability.
Solution Approach 2:
The patent changes the physical and chemical parameters of the anode system by modifying the protective coating properties (thickness, composition, ion conductivity) to optimize the balance between safety and recharge rate. By adjusting these parameters, the system achieves fast charging capability while maintaining safety, overcoming the limitations of traditional graphite anodes.
3Power
If multiple battery cells are externally connected in series to achieve high voltage, then power density increases, but device complexity and bulkiness increase due to external connections and housing requirements
Solution Approach 1:
The patent merges multiple battery cell functions into a single integrated structure. By internally connecting multiple cells in series within one housing and using a unified current collector design, it achieves high voltage and high power density while reducing the number of external connections and simplifying the overall device structure, thus lowering device complexity.
Solution Approach 2:
The patent applies the nesting principle by placing multiple battery cells in a nested or compact internal arrangement within a single housing. The cells are internally connected in series, with current collectors and terminals arranged in a space-efficient manner, allowing high power density to be achieved without increasing external complexity or bulkiness.
4Power
If multiple battery cells are externally connected in series, then high voltage is achieved, but volumetric energy density decreases due to external housing and connection requirements
Solution Approach 1:
The patent merges multiple cells into a single integrated pack with internal series connections, eliminating the need for separate external housings and connections for each cell. This consolidation achieves high voltage while maximizing the utilization of internal space, thereby improving volumetric energy density compared to externally connected configurations.
Solution Approach 2:
The patent nests multiple battery cells within a compact internal structure, arranging them in a space-efficient configuration with internal connections. This nesting approach allows high voltage to be achieved without proportionally increasing external volume, thus maintaining high volumetric energy density while delivering the required voltage levels.
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 higher energy and power densities, improved safety, and reduced bulkiness by integrating unit cells internally, enhancing performance for electric vehicles and portable devices.
Implementation Method 1
using conductive materials, solid electrolytes, and flexible electrolytes to prevent dendrite formation
Implementation Method 2
a cathode active layer comprising a cathode active material... an anode active layer comprising an anode active material
Data Source
AI summary
A high-voltage alkali battery, comprising a plurality of unit cells each comprising: (a) a cathode comprising (i) a cathode current collector; and (ii) a cathode active layer bonded to a first portion, but not a second portion, of the current collector, wherein the cathode active layer comprises a mixture of a cathode active material, a binder, a conducting additive, and a non-flowable electrolyte; (b) an anode; and (c) a separator layer, wherein the cathode, separator, and anode layer are laminated and wound into a unit cell roll with the cathode end having the second portion being protruded out and the anode end having the second portion being protruded out; wherein the unit cells are internally connected in such a manner that the second portion of the cathode of a first unit cell roll is in electronic contact with the second portion of the anode of a second unit cell roll.