Battery Pack Busbar Isolation for Thermal Runaway Short-Circuit Prevention
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Solution Overview
Problem
Thermal runaway in battery cells can cause short circuits between aluminum busbars due to metallic impurities and expansion, leading to potential explosions and further deterioration of thermal runaway.
Innovation Solution
A battery pack design incorporating insulated first isolation tapes that cover busbars and separate them from the housing and pressure relief valves, preventing direct contact and short circuits, while maintaining pressure relief functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cells are arranged in series or parallel via aluminum busbars to enable electrical connection, then electrical connectivity is improved, but the risk of short circuit between busbars increases when thermal runaway occurs
Solution Approach 1:
An insulated tape is introduced as an intermediary component between the aluminum busbars and the housing top wall. This tape acts as a physical barrier that prevents direct contact between busbars and the housing, thereby eliminating the short circuit pathway while maintaining electrical connectivity between cells through the busbars.
Solution Approach 2:
A flexible insulated tape is applied to cover the busbars, creating a thin film barrier that isolates the conductive busbars from potential contact with the housing or other conductive elements. This flexible covering maintains the electrical function while preventing harmful short circuits during thermal runaway events.
2Strength
If the housing top wall provides structural support and protection, then mechanical strength is improved, but it causes short circuit when busbars expand and contact the top wall during thermal runaway
Solution Approach 1:
The insulated tape serves as a mediator between the busbars and the housing top wall. It allows the housing to maintain its structural support function while preventing the harmful electrical contact that would occur when expanded busbars touch the top wall during thermal runaway.
Solution Approach 2:
The flexible insulated tape creates a thin protective film between the expanding busbars and the rigid housing top wall, allowing the housing to retain its mechanical strength while preventing electrical short circuit through the isolation provided by the tape layer.
3Object-generated harmful factors
If pressure relief valves are installed on cells to release pressure during thermal runaway, then pressure relief function is improved, but metallic impurities sprayed from valves can cause short circuit between busbars
Solution Approach 1:
The insulated tape acts as an intermediary barrier that intercepts metallic impurities sprayed from the pressure relief valves before they can reach and bridge the aluminum busbars. This maintains the pressure relief function while preventing the harmful effect of impurity-induced short circuits.
Solution Approach 2:
The insulated tape forms a protective film over the busbars that captures metallic impurities during pressure relief events, preventing these impurities from creating conductive pathways between busbars while allowing the pressure relief valves to function normally.
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
Reduces the risk of short circuits and explosions by isolating busbars with flexible, high-temperature-resistant tapes, enhancing safety during thermal runaway events.
Implementation Method 1
insulated first isolation tapes that cover busbars and separate them from the housing and pressure relief valves
Implementation Method 2
the first isolation tape extends in the length direction of the battery pack and covers a surface that is of the plurality of busbars and that is away from the plurality of cells
Data Source
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AI summary
This application provides a battery pack and an energy storage apparatus. The battery pack includes a housing, and a battery module, a plurality of busbars, and an insulated first isolation tape that are accommodated in the housing. The battery module includes a plurality of cells arranged in a length direction of the battery pack, the plurality of busbars are disposed on a surface on which poles of the plurality of cells are located, two adjacent cells in the plurality of cells are electrically connected via one of the plurality of busbars, and the first isolation tape extends in the length direction of the battery pack and covers a surface that is of the plurality of busbars and that is away from the plurality of cells. There is a gap between the first isolation tape and pressure relief valves of the plurality of cells in a direction in which the poles and the pressure relief valves are spaced from each other. This application resolves a problem that a short circuit occurs in a cell on which thermal runaway occurs and a surrounding cell because of a failure, caused by a high temperature, in designed insulation in a thermal runaway process of the pack. This leads to sparks, thermal runaway diffusion, and short-circuited melt-through of a box body of the pack, and finally leads to fire and explosion of the pack.