Battery Cell Internal Heating With Insulated Subcell Separation

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Solution Overview

Problem

Lithium-ion cells experience reduced performance at low temperatures, and heating them uniformly with a single heating device is inefficient, increasing the risk of thermal runaway, especially in cells with high energy density.

Innovation Solution

The implementation of a thermal insulation body with a thermally insulating material of maximum 1 W/(M · K) thermal conductivity and a heating structure with two heating elements, arranged on opposite surfaces of the insulation body, to heat sub-cells while maintaining electrical insulation and minimizing thermal conduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single heating device is used to heat all lithium-ion cells, then the device complexity is reduced, but the heating time increases and temperature uniformity deteriorates

Engineering Contradiction:
Improveheating device structureVSAvoidheating time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The heating device is segmented into multiple independent heating elements, with each heating element assigned to heat a specific subset of lithium-ion cells. This segmentation allows parallel heating operations across multiple cell groups simultaneously, significantly reducing total heating time while maintaining manageable device complexity through modular architecture

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces spatial distribution of heating elements across different dimensions - placing heating elements in thermal contact with multiple cells at different locations (top, bottom, side surfaces). This multi-dimensional arrangement enables simultaneous heating of multiple cells from different directions, improving heating efficiency and uniformity without requiring a single complex centralized heating device

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of time

If heating temperature is increased to reduce heating time, then the heating speed improves, but the risk of thermal runaway increases

Engineering Contradiction:
Improveheating timeVSAvoidthermal runaway risk
Core Design Contradiction:
Loss of timeVSObject-affected harmful factors

Solution Approach 1:

By dividing the heating function across multiple independent heating elements, each operating at moderate temperatures, the system achieves cumulative heating effect equivalent to high-temperature single-source heating but without the thermal runaway risk. The segmentation distributes thermal stress and prevents localized overheating

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each heating element is designed to provide localized moderate-temperature heating to specific cells or cell groups. The thermal properties (conductivity, capacity) of each heating element can be optimized for its specific location and cell configuration, ensuring uniform temperature distribution and preventing hot spots that could trigger thermal runaway

Inventive Principle:
Principle #3Local quality

3Productivity

If cells are heated to high temperature quickly, then the performance recovery at low temperature is improved, but the safety margin against thermal runaway decreases

Engineering Contradiction:
Improveperformance recovery speedVSAvoidthermal safety
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Multiple heating elements enable parallel heating of multiple cells, achieving rapid overall system performance recovery without requiring any single cell to be heated to dangerously high temperatures. The cumulative effect across segmented heating zones delivers fast performance restoration while maintaining safety margins

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system applies partial heating action through multiple moderate-temperature heating elements rather than excessive single high-temperature heating. This distributed partial action achieves the same or better performance recovery效果 while staying within safe thermal boundaries for each individual heating zone

Inventive Principle:
Principle #16Partial or excessive action

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 solution allows for faster heating of lithium-ion cells and reduces the risk of thermal runaway by minimizing thermal conduction between cells, ensuring uniform heating and maintaining performance even at low temperatures.

Implementation Method 1

a heating structure (103) configured to heat the first subcell (101) and the second subcell (102)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a first insulating body (103) for thermally insulating the first subcell (101) and the second subcell (102) from one another, which first insulating body is arranged in a space between the first and second subcells

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4285433B1Storage cell for an electrical energy store having cell-internal heating, and battery for a motor vehicle
Publication Date: 2025.05.07 BAYERISCHE MOTOREN WERKE AG
  • EP4285433B1 patent drawingFigure 1a~1c
  • EP4285433B1 patent drawingFigure 2~3

AI summary

The invention relates to a cell for the electrochemical storage of electrical energy, having: a first sub-cell (101) and a second sub-cell (102), which are each designed for the electrochemical storage of electrical energy; and a first electrolyte-stable insulation body (103) for thermally insulating the first sub-cell and the second sub-cell from each other, said insulation body being arranged in an interstice between the first and second sub-cells, which is delimited by a side face (111) of the first sub-cell and a side face (112) of the second sub-cell, wherein the first insulation body has a first thermally insulating material (105) having a thermal conductivity of at most 1 W/(m K) and a first heating structure, which is designed to heat the first sub-cell (101) and the second sub-cell (102), and wherein the first insulation body is electrically insulated from both the first sub-cell and the second sub-cell. The invention also relates to a battery which has a cell according to the invention and to a vehicle having a battery according to the invention.