Battery Cell Formation via Sequential Electrolyte Filling
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Solution Overview
Problem
Current methods for forming lithium-ion battery cells require excess additives to prevent decomposition, restrict the selection of electrolyte components, and increase costs, while also limiting the development of new electrolyte formulations due to stability issues.
Innovation Solution
A method involving sequential filling and charging of battery cells with specific electrolyte compositions to deliberately form boundary layers, allowing the use of previously unusable electrolyte components by adding second-type additives only after anode passivation, thereby minimizing decomposition and reducing the need for excess additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If excess additives of the second type are added to the electrolyte from the start, then decomposition of these additives is prevented, but this leads to cost increases
Solution Approach 1:
The patent applies preliminary action by first forming the SEI layer using additives of the first type during initial charging cycles before the second type additives would decompose. This preliminary passivation of the anode surface prevents subsequent decomposition of the second type additives, eliminating the need to add them in excess from the start.
2Reliability
If additives with higher reductive stability are used, then decomposition is reduced, but this restricts selection of additives and can increase costs or reduce performance
Solution Approach 1:
The patent segments the electrolyte additives into two distinct groups with different functions: additives of the first type (with high reductive stability) for initial SEI formation, and additives of the second type (with lower reductive stability but other desirable properties) for subsequent performance enhancement. This segmentation allows each group to be optimized for its specific purpose without compromising the other.
Solution Approach 2:
By performing preliminary passivation with the first type additives, the patent creates protective boundary layers that prevent the second type additives from undergoing harmful reductive decomposition, thereby enabling the use of a broader range of additive compositions.
3Reliability
If other additives are incorporated into the electrolyte to passivate the electrode, then decomposition of second type additives is prevented, but this complicates electrolyte formulation and increases costs
Solution Approach 1:
The patent extracts the passivation function from the second type additives and assigns it specifically to the first type additives. This separation of functions simplifies the overall electrolyte formulation by clearly defining the role of each additive group, rather than requiring complex interactions between multiple types of additives.
Solution Approach 2:
The first type additives perform the preliminary passivation action during initial charging cycles, creating protective SEI and CEI layers before the second type additives are exposed to the electrode surfaces, thereby preventing their decomposition without requiring complex formulations.
4Stability of the object's composition
If electrolyte components that decompose extensively are avoided, then additive stability is maintained, but this severely limits the scope for development of new electrolyte components
Solution Approach 1:
The patent enables the use of previously unstable electrolyte components by performing preliminary passivation with first type additives. This creates protective boundary layers that prevent harmful decomposition of the new components during subsequent cell operation, thereby expanding the range of usable electrolyte formulations.
Solution Approach 2:
The first type additives act as intermediaries that protect the new electrolyte components (second type additives) from direct contact and decomposition at the electrode surfaces. This intermediary protection mechanism allows the incorporation of components that would otherwise be too unstable for use.
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
This approach avoids the excess use of additives, prevents unwanted decomposition, and enhances the freedom in selecting and developing electrolytes, reducing costs and improving battery performance by allowing the use of previously unstable components.
Implementation Method 1
decompose some electrolyte components such as electrolyte additives at the electrodes e.g. the anode
Implementation Method 2
During formation, the freshly manufactured battery cells are charged and discharged for the first time. Important boundary layers form between the electrolyte and the active materials.
Data Source
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AI summary
Method for forming a battery cell (1), wherein the battery cell (1) comprises a housing (2) and at least one anode (3), a cathode (4), a separator (5) arranged between them, and an electrolyte (6) at least partially surrounding the anode (3), the cathode (4), and the separator (5); wherein the method comprises at least the following steps: a) providing the housing (2) and the anode (3), the cathode (4), and the separator (5) arranged therein; b) contacting the anode (3), the cathode (4), and the separator (5) with a first composition (7) of the electrolyte (6); c) electrically charging the battery cell (1) in the first state (8) to a first voltage value (9) between the anode (3) and the cathode (4); d) Supplementing the first composition (7) of the electrolyte (6) with a second composition (11) of the electrolyte (6) in the housing (2) which differs from the first composition (7).