Auxiliary Battery Charge Acceptance Mitigation
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Solution Overview
Problem
Low charge acceptance in batteries, particularly lead-acid batteries used in hybrid and electric vehicles, leads to reduced fuel efficiency and longer charging times, as it causes unnecessary consumption of fossil fuels due to inefficient energy storage and retrieval.
Innovation Solution
A controller system that monitors charge acceptance values and state of charge (SOC) of auxiliary and traction batteries, generating threshold signals to adjust the voltage of the auxiliary battery bus during charging events, applying desulfation and destratification voltages to mitigate sulfation and stratification, thereby improving charging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional charging is used without voltage adjustment, then the charging system is simple to operate, but charge acceptance is low and fuel economy deteriorates
Solution Approach 1:
The patent applies dynamics by making the charging voltage adaptive rather than fixed. The controller dynamically adjusts the charging voltage based on real-time battery state of charge (SOC) measurements and charge acceptance calculations. The system transitions between different voltage levels (e.g., 13.8V, 14.4V, 15.0V) depending on battery conditions, optimizing charge acceptance while maintaining operational simplicity through automated control.
Solution Approach 2:
The patent changes the voltage parameter during charging based on battery SOC and charge acceptance metrics. By monitoring battery voltage, current, and SOC, the system adjusts the charging voltage parameter to match optimal values for different charge states. This parameter adaptation resolves the contradiction by maintaining high charge acceptance without requiring complex manual intervention.
2Productivity
If higher charging voltage is applied continuously, then charge acceptance improves, but battery degradation increases and reliability decreases
Solution Approach 1:
The patent applies periodic action by implementing intermittent high-voltage charging pulses rather than continuous high voltage. The controller periodically applies elevated charging voltages (e.g., 15.0V) for specific time intervals when charge acceptance is low, then returns to normal voltage levels. This periodic high-voltage treatment addresses sulfation and improves charge acceptance while limiting cumulative stress on the battery, thereby maintaining reliability.
Solution Approach 2:
The patent applies preliminary action by detecting low charge acceptance conditions early and responding with voltage adjustment before significant battery degradation occurs. The system continuously monitors charge acceptance metrics and proactively adjusts voltage to prevent sulfation and stratification from developing to harmful levels, thus maintaining both charge acceptance and battery longevity.
3Loss of energy
If charge acceptance mitigation is implemented, then fuel economy improves, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the controller to perform multiple functions: it monitors battery voltage, current, and SOC; calculates charge acceptance; adjusts charging voltage; and manages both auxiliary and traction batteries. By consolidating these diverse functions into a single multi-functional controller, the system improves fuel economy through charge acceptance optimization while minimizing the increase in device complexity that would result from adding separate dedicated components for each function.
4Quantity of substance
If longer charging periods are allowed, then more charge is retained, but time efficiency decreases and productivity worsens
Solution Approach 1:
The patent applies skipping by implementing high-voltage charging pulses that rapidly transfer charge to the battery when charge acceptance is low. Instead of using prolonged low-voltage charging, the controller applies elevated voltage (e.g., 15.0V) for shorter time intervals to 'rush through' the charging process more efficiently. This approach increases the rate of charge retention while reducing overall charging time, resolving the contradiction between charge quantity and time efficiency.
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 effectively increases charge acceptance, reducing the need for longer charging periods and improving fuel economy by addressing chemical degradation in batteries, while minimizing the impact of temperature effects on charging efficiency.
Implementation Method 1
The control logic may generate the threshold signals such that during a next charging event, a voltage of the auxiliary battery achieves a desulfation value
Implementation Method 2
The control logic may generate the threshold signals such that during a next charging event, a voltage of the auxiliary battery achieves a stratification value
Data Source
AI summary
A controller may include input channels configured to receive charge acceptance values of an auxiliary battery and an SOC of a traction battery. The controller may also include output channels configured to provide threshold signals to set a voltage threshold of an auxiliary bus coupled with the auxiliary battery and deriving power from the traction battery. The controller may include control logic configured to generate the threshold signals such that during a next charging event, a voltage of the auxiliary battery achieves a desulfation value. The controller logic may generate the threshold signals in response to the acceptance falling below a predetermined sulfation value and the SOC being above an SOC threshold.