Battery Charging Protection Using Low-Temperature Time Thresholds
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Solution Overview
Problem
Cylindrical lithium batteries are prone to lithium plating during low-temperature charging or regenerative braking, which can lead to ignition, as existing battery protection devices often fail to promptly block charging when temperature drops below 0°C, allowing lithium precipitation to occur.
Innovation Solution
A battery protection apparatus and method that utilizes a processor and memory to monitor the accumulated charging time period at low temperatures and determine whether to permanently block charging and discharging by comparing it with predefined thresholds, controlling charging and discharging operations through specific control signals to prevent lithium plating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If charging current is blocked when temperature drops below 0°C, then lithium plating is prevented, but charging operations are unnecessarily interrupted causing loss of productivity
Solution Approach 1:
The patent changes the protection parameter from simple temperature threshold (0°C) to accumulated charging time at low temperature. The processor monitors both temperature and charging duration, only blocking charging when the accumulated time exceeds a threshold, thereby distinguishing between brief temperature dips and sustained low-temperature charging conditions that actually cause lithium plating.
Solution Approach 2:
The system implements continuous feedback monitoring of temperature and charging time, with the processor dynamically adjusting charging control based on accumulated low-temperature charging duration. This feedback mechanism allows the system to resume charging automatically once the accumulated time threshold is not exceeded, balancing safety with operational continuity.
2Productivity
If delayed blocking of charging current is implemented, then productivity is maintained, but lithium plating occurs causing safety hazards
Solution Approach 1:
The system performs preliminary monitoring and accumulation of low-temperature charging time before taking protective action. By tracking the accumulated charging time in advance and comparing it against a predetermined threshold, the system prevents lithium plating by blocking charging only when necessary, rather than reacting after plating has already occurred.
3Device complexity
If simple temperature-based blocking is used, then device complexity is reduced, but reliability is insufficient due to delayed response to lithium plating risk
Solution Approach 1:
The processor performs multiple functions: it monitors temperature, tracks charging current status, accumulates low-temperature charging time, compares against thresholds, and controls charging blocking. This multi-functional approach achieves reliable lithium plating prevention without adding separate dedicated hardware components for each function.
Data Source
AI summary
Discussed is a protection apparatus that may identify an accumulated charging time period of a charging current applied at least one battery cell and determine whether to permanently block charging and discharging of the at least one battery cell by comparing an accumulated charging time period with a predetermined threshold time period, thereby preventing battery cell ignition due to lithium plating occurring in the battery cell caused from a charging current.