EV Power Supply Temperature Balancing via Dynamic Charge Distribution

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Solution Overview

Problem

Existing power supply systems for electric vehicles with multiple power storage units face challenges in managing temperature variations among units, leading to inefficient energy distribution and potential degradation due to uneven cooling performance, which existing technologies do not adequately address.

Innovation Solution

A power system that includes temperature obtaining means, target power value determining means, and converter control means to distribute the required power value based on the temperature of each power storage unit, ensuring uniform temperature and efficient energy management by adjusting the charge/discharge rates accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple power storage units are provided to increase power supply capacity, then the power supply capacity is improved, but temperature variation among power storage units occurs due to uneven cooling performance

Engineering Contradiction:
Improvepower supply capacityVSAvoidtemperature variation among power storage units
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The patent applies local quality by distributing power storage units with different cooling performances (natural cooling vs. forced cooling) throughout the power storage device, rather than uniform cooling. This creates intentional local differences in cooling capability to balance temperature distribution across all units

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The control device changes operational parameters by adjusting the charge/discharge rates of individual power storage units based on their temperature conditions. When temperature variation exceeds the threshold, the system modifies charge/discharge parameters to reduce the rate for hotter units and increase it for cooler units, thereby equalizing temperatures

Inventive Principle:
Principle #35Parameter changes

2Power

If uniform charge/discharge control is applied to all power storage units, then power supply capacity is maximized, but temperature imbalance occurs leading to reduced reliability

Engineering Contradiction:
Improvepower supply capacityVSAvoidsystem reliability due to temperature imbalance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent implements feedback control by continuously monitoring temperature distribution among power storage units and using this information to adjust charge/discharge rates. The control device receives temperature data, compares it against thresholds, and dynamically modifies operational parameters to maintain temperature balance, ensuring both high power output and system reliability

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from static uniform control to dynamic adaptive control. The charge/discharge rates are not fixed but dynamically adjusted based on real-time temperature conditions of each power storage unit, allowing the system to optimize both power supply and thermal management under varying operational conditions

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2093856B1Power supply system, vehicle using the same, and its control method
Publication Date: 2017.03.01 TOYOTA JIDOSHA KK
  • EP2093856B1 patent drawingFigure 1
  • EP2093856B1 patent drawingFigure 2
  • EP2093856B1 patent drawingFigure 3

AI summary

When the relation of battery temperature Tb1 > battery temperature Tb2 is satisfied, a temperature increase request for a power storage unit (6-2) becomes relatively large. Therefore, a target power value P2* for the power storage unit (6-2) is determined with priority. The target power value P2* is calculated by multiplying the required power value Ps* by a distribution ratio Pr2 (0.5 ≤ distribution ratio Pr2 ≤ 1.0) determined in accordance with temperature deviation between battery temperature Tb1 and battery temperature Tb2. The target power value P1* is determined by subtracting the target power value P2* from the required power value Ps*.