Electric Vehicle Energy Storage Cell Segmentation for Peak Current

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Solution Overview

Problem

The existing systems for electrically powered vehicles require two batteries and an expensive DC/DC converter to manage high currents, leading to increased costs and complexity, as they struggle to provide peak currents efficiently.

Innovation Solution

An electronic device that uses a smaller series-connected energy storage cell configuration to supply peak currents directly from the energy storage device, bypassing the voltage converter, and dynamically adjusts the number of connected cells based on charging states to maintain voltage levels, eliminating the need for a separate starter battery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a DC/DC converter is designed to provide higher peak currents for electrical consumers, then the current supply capability is improved, but the cost and device complexity increase significantly

Engineering Contradiction:
Improvepeak current supply capabilityVSAvoidDC/DC converter complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The energy storage device is segmented into multiple series-connected energy storage cells. During peak current demand, only a subset of these cells is activated to provide the necessary current surge, while the DC/DC converter handles average power requirements. This segmentation allows the system to achieve high peak current capability without requiring the entire energy storage device or an oversized DC/DC converter to be constantly available, thereby reducing overall system complexity and cost.

Inventive Principle:
Principle #1Segmentation

2Power

If two batteries are used (high-voltage battery and starter battery), then the peak current supply capability is improved, but the cost and device complexity increase

Engineering Contradiction:
Improvepeak current supply capabilityVSAvoidbattery system complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The energy storage device with multiple series-connected cells serves multiple functions: it provides average power through the DC/DC converter during normal operation, and it provides peak current supplementation directly to electrical consumers when high current is required. This multi-functionality eliminates the need for a separate starter battery, reducing system complexity while maintaining the ability to handle both average and peak power requirements.

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

Solution Approach 2:

The patent merges the functions of the high-voltage battery and the starter battery into a single energy storage device with multiple series-connected cells. By controlling which cells are activated based on power demand, the system combines the capabilities of two separate batteries into one unified structure, thereby reducing component count and system complexity while maintaining peak current supply capability.

Inventive Principle:
Principle #5Merging (Combining)

3Power

If all energy storage cells are used to supply peak current, then the current supply capability is improved, but the voltage stability and energy management deteriorate

Engineering Contradiction:
Improvepeak current supply capabilityVSAvoidvoltage stability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The system dynamically adjusts which energy storage cells are activated based on real-time power demand and charging states. During peak current events, only the necessary number of cells are engaged to provide the required current surge. The control unit monitors the charging states of individual cells and adjusts activation accordingly, ensuring voltage stability is maintained while providing adequate peak current support. This dynamic approach prevents over-discharge and maintains reliability.

Inventive Principle:
Principle #15Dynamics

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 reduces costs and complexity by eliminating the need for a separate starter battery and optimizing current supply, ensuring efficient power distribution while maintaining voltage within acceptable ranges during peak demand.

Implementation Method 1

The energy store (1) comprises a multiplicity of energy storage cells (7-ZX) connected in series

Methodology Applied
Scientific EffectBattery (electricity): Battery (electricity)

Implementation Method 2

a voltage converter (3) coupled to the energy store (1) for supplying further electrical consumers (4) of the vehicle

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3137335B1Control for electrically driven vehicle, electrically driven vehicle having control, and method
Publication Date: 2022.07.13 BAYERISCHE MOTOREN WERKE AG
  • EP3137335B1 patent drawingFigure 1
  • EP3137335B1 patent drawingFigure 2
  • EP3137335B1 patent drawingFigure 3

AI summary

The invention relates to an electronic device and a method for an at least partially electrically driven vehicle (electric or hybrid vehicle), which vehicle has an electrical energy store, which is provided for driving the vehicle and comprises energy store cells connected in series, and a voltage transformer for supplying at least one further electrical load of the vehicle, which voltage transformer is coupled to the energy store. The device is designed to supply at least one of the further electrical loads of the vehicle with current from a number of energy store cells of the electrical energy store connected in series that is less than the maximum number of energy store cells of the energy store connected in series in the case in which a maximum current for the at least one further electrical load exceeds the maximum current available from the voltage transformer. The invention further relates to at least partially electrically driven vehicles that comprise a device of the type above or are suitable for performing a corresponding method.