Non-aqueous Battery Initial Charging Current Control
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Solution Overview
Problem
In the manufacturing of nonaqueous electrolyte secondary batteries, the initial charging process often results in increased internal pressure due to gas generation, which can lead to activation of the relief valve and render the battery unusable, while also being inefficient in terms of production time.
Innovation Solution
A manufacturing method that adjusts the charging current based on the state of charge (SOC) of the battery, using a high first current value when gas generation does not depend on the charging current and a lower second current value when it does, to minimize gas generation and shorten charging time without excessive pressure increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If charging is performed at a large current value to shorten charging time, then productivity is improved, but gas generation increases causing internal pressure to rise excessively
Solution Approach 1:
The charging current is dynamically adjusted based on the charging stage. A large first current value is applied during the initial charging stage to maximize speed, then automatically switched to a smaller second current value when the SOC reaches a predetermined threshold, thereby shortening overall charging time while preventing excessive gas generation and internal pressure buildup.
Solution Approach 2:
The charging current parameter is changed at a specific charging stage. The system transitions from a high current value (first current value) to a lower current value (second current value) based on SOC threshold detection, optimizing both charging efficiency and safety by adapting the current parameter to the battery's state.
2Loss of time
If charging is performed at a large current value to improve production efficiency, then loss of time is reduced, but gas generation amount increases making the battery unusable
Solution Approach 1:
The charging current is dynamically adjusted based on the charging stage. A large first current value is applied during the initial charging stage to maximize speed, then automatically switched to a smaller second current value when the SOC reaches a predetermined threshold, thereby shortening overall charging time while preventing excessive gas generation and internal pressure buildup.
Solution Approach 2:
The charging current parameter is changed at a specific charging stage. The system transitions from a high current value (first current value) to a lower current value (second current value) based on SOC threshold detection, optimizing both charging efficiency and safety by adapting the current parameter to the battery's state.
3Reliability
If charging is performed at a small current value to prevent gas generation, then reliability is improved, but charging time increases reducing productivity
Solution Approach 1:
The charging current is dynamically adjusted based on the charging stage. A large first current value is applied during the initial charging stage to maximize speed, then automatically switched to a smaller second current value when the SOC reaches a predetermined threshold, thereby shortening overall charging time while preventing excessive gas generation and internal pressure buildup.
Solution Approach 2:
The charging current parameter is changed at a specific charging stage. The system transitions from a high current value (first current value) to a lower current value (second current value) based on SOC threshold detection, optimizing both charging efficiency and safety by adapting the current parameter to the battery's state.
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 approach allows for faster initial charging while preventing excessive internal pressure and reducing gas generation, thereby ensuring the battery is usable and efficiently produced.
Implementation Method 1
charging and discharging is performed such that lithium ions are delivered between a positive electrode made of a positive-electrode active material and a negative electrode made of a negative-electrode active material
Implementation Method 2
the lithium ion is intercalated into a structure of the negative-electrode active material (for example, layered graphite) provided on a negative electrode side
Implementation Method 3
When the initial charging is performed, gas is generated in the battery to increase an internal pressure
Data Source
AI summary
A manufacturing method according to the present invention is a method for manufacturing a nonaqueous electrolyte secondary battery including graphite as a negative-electrode active material. The manufacturing method includes: a step of assembling the battery including a positive electrode and a negative electrode; and a step of performing an initial charging process of performing first charging on the battery. In the initial charging process, charging is performed at a relatively large first current value when a gas generation amount caused in the battery during the charging does not depend on a charging current value, and the charging is performed at a second current value smaller than the first current value when the gas generation amount depends on the charging current value.