Battery Pack Discharge via Case Aperture and Liquid Flow
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Solution Overview
Problem
The existing methods for discharging battery packs by immersion in a conductive liquid are time-consuming, often taking several hours to several days, and pose safety risks due to potential heat generation and ignition from short circuits, especially in lithium ion batteries with high voltages.
Innovation Solution
A battery pack processing apparatus that forms an aperture in the case of the battery pack using a press machine, allowing the discharge liquid to flow inside, which enables faster discharge by mimicking the individual cell immersion process while preventing ignition through controlled pressure and concave-convex pressure member designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the battery pack is immersed in the discharge liquid without individual cell processing, then the discharge time is extended to several times to 10 times longer, but the labor cost and processing time increase significantly
Solution Approach 1:
The invention divides the battery pack into individual cells by breaking the case, allowing each cell to be discharged independently and simultaneously in the discharge liquid, thereby reducing total discharge time compared to processing the entire pack as a single unit
Solution Approach 2:
The case is broken and cells are separated before immersion in the discharge liquid, preparing the battery pack in advance to enable faster discharge by eliminating the protection circuit's current suppression that would otherwise limit the discharge rate of the entire pack
2Productivity
If cells are crushed to facilitate discharge, then discharge efficiency improves, but heat generation and ignition risk increase due to short circuits
Solution Approach 1:
The pressure members are designed with specific local features (concave-convex structures) that concentrate force on the case material rather than the cells, creating localized stress points that break the case without causing widespread cell crushing and short circuits
Solution Approach 2:
The discharge liquid serves as an intermediary cooling medium that is applied after case breaking but before significant heat generation can occur, absorbing heat and preventing ignition while allowing efficient discharge to proceed
3Loss of time
If high pressure is applied to break the case, then discharge liquid can flow inside and discharge time is reduced, but cell crushing and short circuit risk increase
Solution Approach 1:
The pressure members feature concave portions that locally concentrate force on the case material at specific weak points, enabling case breaking at lower overall pressures that do not cause cell crushing, while still achieving sufficient case fracture for discharge liquid penetration
Solution Approach 2:
The pressing process is designed to be dynamic and controlled, applying pressure progressively to first break the case structure, then maintaining lower pressure to prevent cell damage, allowing the system to adapt pressure levels to the changing structural state of the battery pack
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 method allows for rapid discharge of battery packs in a short time, typically within several hours to 24 hours, while ensuring safety by preventing ignition and heat generation, thus reducing labor and costs associated with prolonged discharge processes.
Implementation Method 1
a press machine adapted to press the battery pack and form in the case an aperture through which the discharge liquid can flow inside the case
Implementation Method 2
discharge a battery pack having at least one single cell and a case accommodating the at least one single cell by immersing the battery pack in a discharge liquid
Data Source
Figure 1
Figure 2
Figure 3(A)~3(C)
AI summary
Provided is a battery pack processing apparatus and a processing method with which discharge can be performed in a short time when a battery pack is discharged by immersing the battery pack in a discharge liquid. A processing apparatus A is for discharging a battery pack P having single cells c and a case b by immersing the battery pack P in the discharge liquid. The processing apparatus A includes an aperture-forming machine 20 forming an aperture through which the discharge liquid can flow inside the case b by pressurizing the battery pack P. A state can thus be achieved which is the same as the state that results if the single cells c accommodated in the case b are individually immersed in the discharge liquid. A protection circuit f for preventing an over-discharge is prevented from suppressing a discharge current from the battery pack P, enabling the discharge in a short time.