Solid-State Battery Current Control for Surface Pressure Stability

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Solution Overview

Problem

Existing battery control systems fail to maintain the surface pressure of solid-state batteries above a lower limit value, leading to issues such as increased resistance and potential short circuits.

Innovation Solution

A battery control system that adjusts charge and discharge currents based on upper and lower limit surface pressure differences, using a controller to manage the surface pressure distribution of solid-state batteries to prevent pressure from falling below a threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the charge/discharge current is increased to improve charging speed, then productivity is improved, but the surface pressure of the battery cell falls below the lower limit value causing increased resistance and potential short circuits

Engineering Contradiction:
Improvecharging speedVSAvoidsurface pressure maintenance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic current control by continuously monitoring surface pressure distribution and adjusting charge/discharge current in real-time. The controller dynamically modifies current based on measured pressure values to maintain pressure above the lower limit while maximizing charging speed, transforming the static current control into a dynamic adaptive system.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs feedback control by measuring surface pressure distribution during charging/discharging and using this information to adjust the current. The controller receives feedback from pressure sensors and modifies the charge/discharge current accordingly, creating a closed-loop control system that prevents pressure from falling below the lower limit while maintaining high charging speed.

Inventive Principle:
Principle #23Feedback

2Reliability

If the charge/discharge current is limited to maintain surface pressure above the lower limit value, then reliability is improved, but productivity deteriorates due to reduced charging speed

Engineering Contradiction:
Improvesurface pressure maintenanceVSAvoidcharging speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts current based on real-time pressure measurements rather than using a fixed current limit. This allows the charging speed to be maximized at each moment while ensuring pressure remains above the lower limit, converting a static current restriction into a dynamic optimization process.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the control parameter from a fixed current value to a pressure-dependent current value. By making the current a function of measured surface pressure, the system adapts the charging rate to the actual battery state, allowing higher currents when pressure is adequate and reducing current only when necessary to maintain the pressure threshold.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If uniform pressure distribution is maintained across the battery cell surface, then reliability is improved by preventing localized stress, but device complexity increases due to additional control mechanisms

Engineering Contradiction:
Improvepressure distribution uniformityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the battery cell surface into multiple measurement zones with pressure sensors distributed across different locations. By segmenting the pressure monitoring into discrete zones, the system can detect localized pressure variations and target specific areas for adjustment, reducing the complexity compared to attempting uniform control across the entire surface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system applies local quality control by adjusting pressure or current based on measurements from specific zones rather than treating the entire surface uniformly. This allows targeted intervention in areas where pressure falls below the lower limit while maintaining optimal conditions in other zones, simplifying the control mechanism compared to global uniform control.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4715957A1Battery control system and battery control method
Publication Date: 2026.03.25 NISSAN MOTOR CO LTD
  • EP4715957A1 patent drawingFigure 1
  • EP4715957A1 patent drawingFigure 2
  • EP4715957A1 patent drawingFigure 3

AI summary

A battery control system (1) controls a solid-state battery including a battery cell (21) having a solid electrolyte and a negative electrode containing lithium. The battery control system includes: a measurement unit that measures a surface pressure distribution from an actual measured value or an estimated value of a surface pressure distribution on a main surface of the battery cell (21); and a control unit that controls a charge/discharge current of the solid-state battery, the charge/discharge current being at least one of a charge current and a discharge current. The control unit determines the charge/discharge current according to an upper-limit surface pressure difference and a lower-limit surface pressure difference, the upper-limit surface pressure difference being a difference between a measured value of the surface pressure distribution measured by the measurement unit and an upper limit surface pressure of the battery cell (21), the lower-limit surface pressure difference being a difference between the measured value of the surface pressure distribution measured by the measurement unit and a lower limit surface pressure of the battery cell (21).