Battery Module Propagation Test Cell With Internal Nail Trigger
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Solution Overview
Problem
Existing propagation tests for secondary battery cells require external mechanical stress and cannot accurately record temperature and mechanical stress directly at the point of damage, leading to unrealistic simulation of thermal runaway and potential erroneous measurement results.
Innovation Solution
A propagation test cell is integrated within a cell module, equipped with a mechanism to insert a nail into an adjacent battery cell and featuring integrated temperature and pressure measuring points, allowing for internal initialization of a short circuit and realistic simulation of thermal runaway without external damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a nail is inserted from the outside into a battery cell for propagation testing, then the test can be conducted according to existing standards, but temperature and chemical degradation cannot spread equally in all spatial directions and external sealing is required
Solution Approach 1:
Instead of inserting the nail from the outside of the battery cell, the invention inverts the approach by placing the nail inside a propagation test cell that is integrated within the cell module. The nail is then activated to penetrate an adjacent battery cell from the inside, eliminating the need for external sealing and mechanical stress on the battery cell exterior.
Solution Approach 2:
The invention implements nesting by integrating the propagation test cell within the battery cell module structure. The test cell contains the nail mechanism, which is nested inside the module, allowing the nail to be activated internally to penetrate adjacent battery cells without requiring external access or sealing.
2Reliability
If a nail is inserted from the outside to create a short circuit, then thermal runaway can be triggered, but thermal energy input from adjacent battery cells causes thermal runaway of multiple cells leading to erroneous measurement results
Solution Approach 1:
The invention extracts the nail and its activation mechanism from the external environment and places it inside the propagation test cell within the module. This allows the short circuit to be initiated from a controlled internal position, enabling the study of thermal runaway propagation from a single point without external interference or premature thermal runaway of adjacent cells.
3Manufacturing precision
If external devices are used to conduct propagation tests, then the test can be performed according to standards, but temperature and chemical degradation cannot spread equally in all spatial directions from the point of damage
Solution Approach 1:
The propagation test cell is designed with multi-functionality, serving both as a structural component of the battery module and as a test initiation device. The test cell integrates the nail mechanism, housing, and activation system, allowing it to fulfill multiple functions: maintaining module structural integrity, providing a controlled environment for nail activation, and enabling standardized propagation testing while ensuring uniform thermal and chemical degradation in all spatial directions.
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 enables realistic simulation of thermal runaway in all spatial directions, records temperature and mechanical stress directly at the point of damage, and maps the thermal and mechanical behavior of original battery cells, providing accurate measurement results without external mechanical stress or sealing.
Implementation Method 1
a drive mechanism (6), which is arranged in the interior of that first housing part (4) and which is configured to move the nail (5) along a movement axis (MA)
Implementation Method 2
integrated temperature and pressure measuring points, allowing for internal initialization of a short circuit and realistic simulation of thermal runaway without external damage
Implementation Method 3
integrated temperature and pressure measuring points, allowing for internal initialization of a short circuit and realistic simulation of thermal runaway without external damage
Implementation Method 4
The propagation of secondary electric battery cells describes the effect of thermal runaway, wherein an electrical short circuit occurs due to impurities on the separator or external mechanical degradation inside a battery cell
Data Source
AI summary
A propagation test cell includes a first substantially cuboid housing part and a drive mechanism arranged therein. The drive mechanism moves a nail along a movement axis. A second housing part has a reference surface parallel and directed opposite to a reference surface of the first housing part and is in contact therewith. The second housing part has a passage coaxial with the movement axis of the nail. The passage has a passage cross-sectional area greater than the diameter of the shank of the nail. Dimensions of the outer form of the propagation test cell correspond to a multiple of the respective dimensions of a battery cell with which the propagation test cell can be arranged within a cell module, so that the propagation test cell can be substituted with at least one additional battery cell or with a multiple thereof within a cell module.