Solid-State Li-Ion Battery SOC Limit Reset After Overcurrent
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Solution Overview
Problem
All-solid-state lithium ion batteries with lithium titanate anodes experience capacity degradation and heat generation due to spontaneous overcharging, which reduces safety during regenerative control events like vehicle slips or sudden accelerations.
Innovation Solution
A control system that monitors and adjusts the State of Charge (SOC) limit by calculating a new SOC threshold based on overcurrent events, preventing further overcharging and controlling current input/output to maintain safe operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the battery is controlled to maintain SOC at most at the SOC limit to prevent overcharging, then battery safety is improved, but the battery cannot utilize full capacity during regenerative control events like wheel slip or sudden acceleration
Solution Approach 1:
The patent implements dynamic adjustment of the SOC limit based on battery temperature and charging history. The control unit calculates a decreased amount of SOC limit when overcharging occurs, and adjusts the SOC limit accordingly. This allows the system to adaptively balance safety and capacity utilization rather than using a fixed conservative limit.
Solution Approach 2:
The control unit continuously monitors the charged capacity and compares it with the SOC limit. When overcharging is detected (charged capacity exceeds 100% of SOC), the system calculates a decreased SOC limit amount based on the overcharge magnitude and adjusts future SOC limits. This feedback mechanism prevents repeated overcharging while allowing full capacity utilization when conditions permit.
2Object-affected harmful factors
If the SOC limit is reduced after overcharging to prevent further overcharge, then heat generation is suppressed, but the battery capacity is unnecessarily restricted
Solution Approach 1:
The patent changes the SOC limit parameter dynamically based on battery temperature and overcharge history. When overcharging occurs, the control unit calculates a decreased SOC limit amount proportional to the overcharge severity. This temporary reduction suppresses heat generation from repeated overcharging, but the system can restore higher capacity utilization when temperature conditions improve and no further overcharge occurs.
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 control system effectively suppresses heat generation and maintains battery safety by dynamically adjusting the SOC limit, ensuring the battery operates within safe capacity ranges even after initial overcharging events.
Implementation Method 1
the resistance heat generation may occur because the SOC limit has decreased
Data Source
AI summary
Provided is a control system of an all-solid-state lithium ion battery which is capable of improving safety. The control system of an all-solid-state lithium ion battery installed in a vehicle includes: an all-solid-state lithium ion battery connected to a motor for driving a vehicle; and a control unit controlling input and output of a current to the all-solid-state lithium ion battery, wherein the all-solid-state lithium ion battery includes an anode containing lithium titanate, and the control unit adds the number of seconds or a current value whenever the charged capacity of the all-solid-state lithium ion battery exceeds 100% of SOC due to an overcurrent, calculates the decreased amount of the SOC limit based on a value obtained from the addition, calculates the second specified SOC based on the decreased amount of the SOC limit, and controls the all-solid-state lithium ion battery based on the second specified SOC.