Battery Preheating Circuit for Uniform Cell Temperature

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Solution Overview

Problem

Temperature unevenness among cells in a battery assembly affects the performance and service life of the battery assembly, leading to reduced endurance mileage and increased risk of faults in the vehicle.

Innovation Solution

A thermal management system with a preheating control valve and preheating branch that disconnects the battery assembly from the second heat exchange circuit when a temperature difference exceeds a threshold, forming a battery preheating circuit to uniformly heat the cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the battery assembly is heated using the second heat exchange circuit, then the battery temperature is increased, but the temperature distribution among cells becomes uneven

Engineering Contradiction:
Improvebattery temperatureVSAvoidtemperature distribution uniformity
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The heating system is segmented into two independent circuits: the first heat exchange circuit for uniform heating of all cells, and the second heat exchange circuit for selective or supplemental heating. This segmentation allows each circuit to perform its specific function optimally without causing temperature unevenness

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first heat exchange circuit acts as an intermediary system that provides uniform baseline heating to all battery cells before the second heat exchange circuit operates. This intermediary heating ensures temperature uniformity across all cells, preventing the temperature distribution problems that would occur with direct heating alone

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If the battery assembly operates at low temperature, then energy consumption is reduced, but the battery capacity and output power decrease

Engineering Contradiction:
Improveenergy consumptionVSAvoidbattery capacity and output power
Core Design Contradiction:
Use of energy by moving objectVSPower

Solution Approach 1:

The system performs preliminary heating of the battery assembly using the first heat exchange circuit before the battery needs to deliver high power. This preliminary action brings the battery to an optimal temperature range, ensuring high capacity and output power when needed while avoiding continuous heating that would waste energy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control system continuously monitors battery temperature and state of charge, and dynamically adjusts the operation of both heat exchange circuits. When the battery temperature is sufficient, heating is reduced or stopped; when temperature drops or power demand increases, heating is activated, optimizing the balance between energy consumption and battery performance

Inventive Principle:
Principle #23Feedback

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

Uniform temperature distribution among battery cells prolongs the service life and improves capacity and output power, reducing battery and vehicle faults while lowering maintenance costs.

Implementation Method 1

The condenser is configured to perform heat exchange on the first heat exchange medium and the second heat exchange medium, allowing the second heat exchange medium to heat the battery assembly

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4699855A1Thermal management system and vehicle
Publication Date: 2026.02.25 ZHEJIANG GEELY HLDG GRP CO LTD
  • EP4699855A1 patent drawingFigure 1
  • EP4699855A1 patent drawingFigure 2
  • EP4699855A1 patent drawingFigure 3

AI summary

A thermal management system (1) includes a compressor (101), a condenser (102), a chiller (103), and a battery assembly (105). The compressor (101), the condenser (102), and the chiller (103) are in communication with each other sequentially to form a first heat exchange circuit (11); the condenser (102) is in communication with the battery assembly (105) to form a second heat exchange circuit (12); and the condenser (102) is configured to perform heat exchange on a first heat exchange medium and a second heat exchange medium, allowing the second heat exchange medium to heat the battery assembly (105). The thermal management system further includes: a preheating control valve (109), disposed in the second heat exchange circuit (12); and a preheating branch (110), selectively connected to the battery assembly (105) based on the preheating control valve (109). In a case that a temperature difference among a plurality of cells in the battery assembly exceeds a temperature difference threshold, the battery assembly (105) is disconnected from the second heat exchange circuit (102) and is communicated with the preheating branch (110) through the preheating control valve (109), to form a battery preheating circuit (13) for preheating the plurality of cells. Further disclosed is a vehicle including the thermal management system. According to the thermal management system, temperatures of the plurality of cells in the battery assembly are uniform, the service life of the battery assembly is prolonged, the battery capacity and output power of the battery assembly are improved, and the risk of battery faults is reduced, thereby prolonging the service life of the whole vehicle, improving the performance and endurance mileage of the whole vehicle, and reducing the risk of faults of the whole vehicle, and thus reducing the maintenance costs.