Prismatic Battery Cell Housing for Edge Pressure Control
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Solution Overview
Problem
Existing methods for preventing the formation of metallic lithium in prismatic battery cells are either costly, complex, or ineffective, particularly at the edges of the stack, leading to increased production time and cost, and insufficient contact pressure results in high resistance and potential difference, causing metallic lithium formation.
Innovation Solution
A battery cell design featuring a holding case with inwardly projecting support areas on its main faces to ensure consistent contact pressure between the anode and cathode, using a folded film, elastic foam, or shrinkable plastic film to maintain contact and prevent metallic lithium formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a stacking process is used to improve energy density, then energy density is improved, but contact pressure between electrodes becomes insufficient leading to metallic lithium formation
Solution Approach 1:
The holding case incorporates localized support areas (protruding structures) at specific positions where contact pressure is needed most, rather than applying uniform pressure throughout. This allows targeted reinforcement of contact pressure at electrode edges and interfaces while maintaining the overall stacking configuration for high energy density.
Solution Approach 2:
The holding case acts as an intermediary component between the electrode stack and the external environment. It transmits and distributes compression forces uniformly across the electrode stack, ensuring consistent contact pressure throughout while allowing the stacking process to maintain high energy density.
2Reliability
If adhesive separator is used to prevent metallic lithium formation, then metallic lithium formation is prevented, but production time and cost increase
Solution Approach 1:
The invention extracts the function of ensuring contact pressure from the separator and places it in the holding case. This allows the use of conventional, simpler separators without adhesive layers, maintaining production efficiency while preventing metallic lithium formation through mechanical contact pressure management.
Solution Approach 2:
Instead of modifying the separator with adhesive properties, the invention creates a separate structural element (holding case with support areas) that copies and reinforces the contact pressure function. This modular approach maintains simple separator manufacturing while achieving the same protective effect.
3Reliability
If adhesive separator is used to prevent metallic lithium formation, then metallic lithium formation is prevented, but production cost increases
Solution Approach 1:
The invention extracts the contact pressure assurance function from the separator material itself and implements it through the holding case structure. This eliminates the need for expensive adhesive separators, reducing material costs while maintaining the protective function against metallic lithium formation.
Solution Approach 2:
The holding case provides a simple, inexpensive mechanical solution using basic structural elements rather than expensive specialized separator materials. This approach achieves reliable metallic lithium prevention through straightforward mechanical design rather than costly material science solutions.
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 maintains low resistance and prevents metallic lithium formation, enabling high energy density batteries with reduced production complexity and cost.
Implementation Method 1
a holding case (16) capable of containing the stack of electrochemical elements (12) and exerting support on the ends of said stack of electrochemical elements (12)
Implementation Method 2
The electrolyte forms a passivation layer on the surfaces of the active materials (in English 'SEI', Solid Electrolyte Interphase). This step is particularly important to obtain a stable electrochemical system
Implementation Method 3
The potential difference determining the operation of the cell is then greater and a reduction reaction would occur, according to the equation below, and the lithium ions would therefore become metallic lithium
Data Source
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AI summary
The cell (10) comprises a stack of electrochemical elements (12), comprising a cathode, an anode, and a separator impregnated with electrolyte interposed between the anode and the cathode, and comprising a holding housing (16) having two main faces (20) between which the stack of electrochemical elements (12) is compressed. Each main face (20) has at least one bearing area (22) projecting inwards in the vicinity of at least one edge of the main face (20), said bearing area (22) bearing on the stack of electrochemical elements (12).