Prismatic Battery Cell Springs for Electrode Expansion Pressure Control
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Solution Overview
Problem
High-expansion anode electrodes in prismatic battery cells experience issues with unacceptable expansion leading to deformation of the hard case and poor electrode contact due to excessive or insufficient pressure, affecting battery performance and lifespan.
Innovation Solution
Incorporation of built-in springs within the prismatic battery cell to maintain a desired electrode pressure range by absorbing the large expansion of high-expansion anode electrodes, using lithium metal or high-silicon content anodes, and controlling pressure through spring geometry and number.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-expansion anode electrodes are used to increase energy density, then battery capacity is improved, but electrode stack expansion causes hard case deformation and poor electrode contact
Solution Approach 1:
The patent introduces a movable pressure control unit with springs that can dynamically adjust its position along the longitudinal axis of the battery cell. This dynamic mechanism compensates for electrode stack expansion by moving the pressure control unit to maintain optimal contact pressure, resolving the contradiction between using high-capacity expanding anodes and maintaining reliable electrode contact.
Solution Approach 2:
The pressure control unit changes the pressure parameter applied to the electrode stack by adjusting spring compression. When the anode expands, the spring compresses to maintain constant contact pressure, ensuring reliable electrode contact despite volume changes in high-capacity anode materials.
2Quantity of substance
If high-expansion anode electrodes are used to increase energy density, then battery capacity is improved, but hard case deformation occurs
Solution Approach 1:
The movable pressure control unit dynamically adjusts its position to compensate for electrode expansion, distributing mechanical stress away from the hard case walls. This prevents case deformation while allowing the use of high-expansion anode materials for increased capacity.
Solution Approach 2:
The pressure control unit acts as an intermediary between the expanding electrode stack and the hard case. It absorbs the expansion forces through spring compression and movable displacement, preventing these forces from deforming the hard case while enabling high-capacity anodes.
3Reliability
If spring pressure is increased to maintain electrode contact, then electrode contact stability is improved, but electrode damage occurs due to excessive pressure
Solution Approach 1:
The spring mechanism changes the pressure parameter dynamically based on electrode stack volume. The spring compresses as the electrode expands, automatically reducing pressure to maintain optimal contact without exceeding damage thresholds, thus preserving electrode structural integrity while ensuring contact stability.
Solution Approach 2:
The spring acts as a cushioning element that anticipates and absorbs expansion forces before they can cause damage. By pre-positioning the spring to compress during expansion, it maintains contact pressure within safe limits, preventing both loss of contact and electrode damage.
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
Maintains optimal electrode pressure, preventing deformation and improving battery performance and lifespan while enabling high energy density.
Implementation Method 1
a built-in spring configured for pressing against the electrode stack in a direction perpendicular to the planar surface of each of the electrode pair layers
Data Source
AI summary
An apparatus for prismatic battery cell is provided. The apparatus includes a hard outer case defining an internal volume. The apparatus further includes an electrode stack disposed within the internal volume and includes a pair of an anode electrode and a cathode electrode. The electrode stack further includes a plurality of electrode pair layers stacked parallel to each other. The electrode pair layers each include a planar surface. The apparatus further includes a built-in spring configured for pressing against the electrode stack in a direction perpendicular to the planar surface of each of the electrode pair layers.