Battery Pack Impact Detection Using Conductive Overlap Sensors

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Solution Overview

Problem

Existing vehicle systems struggle to accurately detect impact loads applied directly to electrical storage devices, as acceleration sensors installed in vehicles primarily monitor vehicle body impacts and fail to discern impacts on the storage devices.

Innovation Solution

The electrical storage device incorporates impact detection units with conductive members and insulating covers, disposed to overlap with battery cells, which detect impact loads by measuring voltage drops and are integrated with a cooling unit for efficient heat transfer and monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If acceleration sensors are installed in the vehicle body to detect impact loads, then vehicle body impacts can be detected, but impacts on the electrical storage device cannot be accurately detected

Engineering Contradiction:
Improveimpact detection accuracyVSAvoidimpact information on storage device
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent divides the detection system into two independent parts: acceleration sensors for vehicle body impact detection and impact detection units for electrical storage device impact detection. This segmentation allows each sensor to be optimally positioned and configured for its specific detection target, resolving the contradiction between vehicle body monitoring and storage device monitoring.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The impact detection unit acts as an intermediary between the electrical storage device and the control system. It directly contacts the storage device housing and detects impacts through conductive members that deform under impact force, providing accurate impact information that neither vehicle body sensors nor direct storage device sensors could provide alone.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If impact detection units are added to detect storage device impacts, then impact detection accuracy improves, but device complexity increases

Engineering Contradiction:
Improveimpact detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The impact detection unit merges multiple functions into a single component: impact detection through conductive member deformation, electrical insulation through the insulator material, and mechanical coupling to the storage device housing. This integration achieves accurate impact detection without proportionally increasing system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The impact detection unit serves multiple purposes: detecting impact magnitude, providing electrical insulation between conductive members and housing, and mechanically linking the detection system to the storage device structure. This multi-functionality reduces the need for separate components, offsetting the added complexity with functional consolidation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If conductive members are disposed to overlap with battery cells, then impact detection sensitivity improves, but risk of electrical short circuit increases

Engineering Contradiction:
Improveimpact detection sensitivityVSAvoidelectrical short circuit risk
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The insulator material acts as an intermediary barrier between the conductive members and the battery cells. It allows the conductive members to be positioned in close proximity to the battery cells for high impact sensitivity while preventing direct electrical contact, thus eliminating the short circuit risk.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The insulator material is applied locally at critical interfaces where conductive members approach battery cells or housing. This localized insulation provides electrical protection exactly where needed without requiring complete insulation of the entire detection unit, maintaining impact sensitivity while preventing shorts.

Inventive Principle:
Principle #3Local quality

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 solution enables precise detection of impact loads on the electrical storage device, improves cooling efficiency, reduces part count, and ensures accurate monitoring of battery cell status through integrated impact and temperature sensing.

Implementation Method 1

the impact detection unit includes a cover made of an insulator that covers the parts of the conductive members that overlap with the wall portion and the parts of the conductive members that overlap with the battery cells

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

when an impact load is input to the electrical storage device, the conductive members break or deform with the deformation of the cover, resulting in a drop in the voltages output from the conductive members

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Implementation Method 3

Heat transfer between the battery cells and the cooling unit is performed via the cover

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4700904A1Electrical storage device and method of detecting impact load input to electrical storage device
Publication Date: 2026.02.25 TOYOTA JIDOSHA KK
  • EP4700904A1 patent drawingFigure 1
  • EP4700904A1 patent drawingFigure 2
  • EP4700904A1 patent drawingFigure 3

AI summary

An electrical storage device includes a plurality of battery cells; a battery case that houses the battery cells; and an impact detection unit which is disposed relative to a wall portion configuring a part of the battery case, the impact detection unit includes conductive members that are disposed so as to overlap with the battery cells as viewed from a predetermined direction and that have a predetermined voltage applied to them, and the impact detection unit includes a cover that is made of an insulator and that covers parts of the conductive members which overlap with the wall portion and parts of the conductive members which overlap with the battery cells as viewed from the predetermined direction.