Battery Module With Rolled Electrode Bodies
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Solution Overview
Problem
Battery modules with rolled electrode bodies face uneven load distribution due to stepped edges of anode, cathode, and separator sheets, leading to non-uniform pressure application and reduced cycle life performance when subjected to restraining loads, particularly in vehicle installations.
Innovation Solution
Positioning the trailing and leading edges of the anode, cathode, and separator sheets outside the portions of the rolled electrode body that receive the restraining load, ensuring uniform pressure application and using space holding plates to maintain the cells in a restrained condition, thereby preventing uneven load distribution and enhancing cycle life performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the cells are arranged in an array and held in a restrained condition with a large number of cells, then the battery module can be installed in limited vehicle space, but a substantial load is applied to the individual cells leading to reduced service life and poor charge-discharge characteristics
Solution Approach 1:
The patent applies local quality by positioning the trailing edges of collector sheets and separator sheets at specific locations outside the pressed portion of the rolled electrode body. This creates a non-uniform structure where the pressed portion has uniform pressure distribution while the trailing edges are positioned to avoid interference. The local modification of sheet positioning resolves the contradiction by allowing restrained condition installation while protecting the electrode body from uneven load distribution.
2Volume of moving object
If the trailing edges of collector sheets and separator sheets are positioned within the pressed portion of the rolled electrode body, then the structure is compact, but uneven load distribution occurs leading to non-uniform pressure application and reduced cycle life
Solution Approach 1:
The patent extracts the trailing edges of the collector sheets and separator sheets from the pressed portion of the rolled electrode body by positioning them outside this region. This separation removes the source of uneven load distribution from the critical pressed area, allowing uniform pressure application while maintaining compact overall structure. The trailing edges are taken out of the interference zone to preserve both compactness and pressure uniformity.
3Stability of the object's composition
If the cells are subjected to restraining load in the direction of arrangement, then the battery module maintains structural stability in vehicle installation, but the rolled electrode bodies experience non-uniform pressure leading to deteriorated output characteristics
Solution Approach 1:
The patent applies preliminary action by pre-positioning the trailing edges of collector sheets and separator sheets outside the pressed portion before the restraining load is applied. This advance positioning prevents the formation of uneven load distribution and step-shaped surfaces that would otherwise occur under restraint. By preparing the sheet positions in advance, the electrode body maintains both structural stability under load and uniform pressure distribution for optimal output characteristics.
Data Source
AI summary
Each of battery cells (12) that constitute a battery module includes a flat-shaped rolled electrode body (30) formed by rolling a sheet-like anode collector (32) and a sheet-like cathode collector (34) along with a sheet-like separator, and a trailing edge (32E) of the sheet-like anode collector (32) and a trailing edge (34E) of the sheet-like cathode collector (34) are located at a position (30B) outside a portion of the rolled electrode body (30) which substantially receives a restraining load. The battery module, in which the restraining load is applied to the cells, achieves long service life while maintaining good output characteristics.