Sealed Battery Pack Airflow for Uniform Cell Temperature

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Solution Overview

Problem

Existing battery systems experience inhomogeneous temperature distribution due to varying heat dissipation rates among battery cells, leading to premature power throttling, uneven aging, and reduced lifespan, necessitating air cooling methods that compromise housing integrity.

Innovation Solution

A battery system with a hermetically sealed metallic housing and internal fans controlled by a battery management system to redistribute heat within the battery housing, ensuring homogeneous temperature distribution without external openings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If air cooling with inlet and outlet openings is used, then heat dissipation is improved, but housing integrity and sealing are compromised

Engineering Contradiction:
Improveheat dissipationVSAvoidhousing sealing
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent introduces a heat transfer fluid as an intermediary substance that circulates through the battery housing to transfer heat from the battery cells to the housing walls, enabling heat dissipation without requiring direct openings in the housing that would compromise sealing

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a liquid cooling system where a heat transfer fluid circulates through channels within the battery housing, using hydraulic principles to transfer thermal energy from the battery cells to the external environment while maintaining housing integrity

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Quantity of substance

If battery cells are arranged close together for high energy density, then energy density is improved, but temperature uniformity deteriorates

Engineering Contradiction:
Improveenergy densityVSAvoidtemperature uniformity
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The patent implements temperature sensors at multiple locations within the battery pack and adjusts the cooling fluid distribution to provide localized cooling where needed, ensuring uniform temperature distribution across densely packed battery cells with different thermal conditions

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses temperature sensors to monitor the thermal state of individual battery cells and adjusts the cooling fluid flow accordingly, creating a feedback control system that maintains temperature uniformity despite the high density arrangement of battery cells

Inventive Principle:
Principle #23Feedback

3Reliability

If a single cell reaches critical temperature, then safety is ensured, but overall battery power is throttled prematurely

Engineering Contradiction:
Improvebattery safetyVSAvoidbattery power
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements a proactive cooling system that anticipates temperature rise in battery cells and activates cooling before critical temperatures are reached, preventing the need for power throttling while maintaining safety margins

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent dynamically adjusts cooling parameters such as fluid flow rate and temperature based on real-time battery thermal conditions, optimizing the balance between safety requirements and power output by modifying cooling intensity rather than simply throttling power

Inventive Principle:
Principle #35Parameter changes

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 cell aging and extended battery performance by evenly distributing waste heat, preventing premature throttling and enhancing lifespan while maintaining a lightweight and cost-effective design.

Implementation Method 1

at least one fan is arranged within the battery housing, wherein the at least one fan can be controlled by the battery management system depending on whether a temperature threshold of the individual battery cells is exceeded

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

During operation, each individual battery cell exhibits a certain power loss. This power loss is dissipated as waste heat into the interior of the battery housing

Methodology Applied
Scientific EffectJoule Heating: Joule Heating

Implementation Method 3

A battery system comprises a metallic battery housing with a base body having a first cover element and a second cover element

Methodology Applied
Scientific EffectThermal Conduction: Conduction (thermal)

Data Source

PatentEP3844823B1Battery system and method for homogeneous temperature distribution within the battery system, use of the battery system and vehicle therewith
Publication Date: 2026.02.18 ROBERT BOSCH GMBH
  • EP3844823B1 patent drawingFigure 1
  • EP3844823B1 patent drawingFigure 2
  • EP3844823B1 patent drawingFigure 3

AI summary

The invention relates to a battery system (200) with a battery housing which comprises a main part (201), a first cover element (202), and a second cover element (203). The first cover element (202) closes a first open end face of the main part (201), and the second cover element (203) closes a second open end face of the main part (201). The battery system also comprises a battery cell holder (204) which has a plurality of battery cells (205), said battery cell holder (204) being arranged within the battery housing, The battery system also comprises a battery management system (109) which is configured to monitor the plurality of battery cells (205) and detect temperatures of the individual battery cells (205). The invention is characterized in that at least one fan (206) is arranged within the battery housing, and the at least one fan (206) is actuated by the battery management system (109) depending on a threshold being exceeded by the temperature of the individual battery cells (205).