Bipolar Battery Pack Counter-Flow Cooling Passage Design
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Solution Overview
Problem
Conventional bipolar secondary batteries experience biased temperature distribution during charging and discharging, leading to inefficient cooling and potential degradation in performance.
Innovation Solution
A battery pack design featuring a bipolar secondary battery assembly with a cooling passage that includes an inlet passage, an outlet passage, and a direction turning portion, integrated within a casing, which allows for counter-flow cooling to evenly distribute temperature across the battery modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a cooling medium flows in one direction through the battery pack, then the cooling structure is simple, but temperature difference generates in the cooling medium causing biased temperature distribution in the bipolar secondary battery
Solution Approach 1:
The patent introduces a direction turning portion that reverses the flow direction of the cooling medium. Instead of flowing in a single direction from inlet to outlet, the cooling medium flows through the battery pack, changes direction at the direction turning portion, and returns through the battery pack in the opposite direction. This counter-flow arrangement equalizes temperature distribution across the bipolar secondary battery by exposing both upstream and downstream regions to cooling medium at different temperatures.
Solution Approach 2:
The patent adds a dimensional element to the cooling path by introducing a direction turning portion that creates a three-dimensional flow path. The cooling medium doesn't just flow linearly through one dimension but navigates through multiple directions (inlet passage → direction turning portion → outlet passage → direction turning portion → inlet passage), effectively utilizing spatial dimensions to achieve uniform cooling across the battery pack.
2Device complexity
If conventional cooling methods are used, then the cooling system is simple, but biased temperature distribution leads to performance degradation
Solution Approach 1:
The patent introduces a direction turning portion that inverts the flow direction of the cooling medium, creating a counter-flow cooling system. This additional component, while increasing device complexity, ensures uniform temperature distribution across the bipolar secondary battery, preventing performance degradation and improving reliability.
Solution Approach 2:
The patent implements a feedback mechanism where the cooling medium's temperature changes as it flows through the battery pack, and the direction turning portion ensures that this temperature variation is distributed evenly across all regions. The cooling system effectively uses the temperature feedback from upstream regions to cool downstream regions, maintaining uniform temperature and preventing performance degradation.
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
The counter-flow cooling method ensures uniform temperature distribution, reduces the amount of cooling medium required, and minimizes power consumption, thereby enhancing battery performance and longevity.
Implementation Method 1
When the bipolar secondary battery is charged/discharged, a current flows in the direction of stacking of the bipolar electrodes. Consequently, heat builds up in the bipolar secondary battery, and the temperature of bipolar secondary battery increases.
Implementation Method 2
As a method of cooling the bipolar secondary battery, a cooling medium may be caused to flow in a direction along a plane orthogonal to the stacking direction of the bipolar electrodes.
Data Source
AI summary
The battery pack of the present invention includes a bipolar secondary battery used as a power source of a vehicle, and a cooling passage allowing flow of a cooling medium. The cooling passage is integrated with a casing. The cooling passage includes an inlet passage provided along that one of a plurality of battery modules which is positioned at one end of the plurality of battery modules for introducing the cooling medium from an input port, an outlet passage provided along that one of the plurality of battery modules which is positioned at the other end of the plurality of battery modules for discharging the cooling medium from an outlet port, and a direction changing portion provided between the inlet passage and the outlet passage changing the flow direction of cooling medium coming from the inlet passage and passing the cooling medium to the outlet passage. According to the present invention, the cooling medium is discharged to the same side as the introducing side. Specifically, the direction of cooling medium flowing in the inlet passage is opposite to the direction of cooling medium flowing in the outlet passage. As the cooling medium is caused to flow in this manner (a so-called counter flow method), temperature distribution in bipolar secondary battery can be made uniform.