Parallel Lead and Lithium Titanate Battery Voltage Mismatch
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Solution Overview
Problem
Nonaqueous electrolyte batteries using lithium titanate for the negative electrode exhibit rapid self-discharge and high cost per capacity, making them challenging for practical use, especially when combined with lead storage batteries due to voltage mismatch issues that lead to battery deterioration.
Innovation Solution
A battery system comprising a lead storage battery connected in parallel with a nonaqueous electrolyte battery using lithium titanate for the negative electrode, where the nonaqueous electrolyte battery has a positive electrode with a spinel structure and a specific negative-electrode-mixture layer thickness and weight per unit area, maintaining a constant open-circuit voltage and low internal resistance to mitigate voltage changes and battery deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a nonaqueous electrolyte battery using lithium titanate for the negative electrode is connected in parallel with a lead storage battery, then rapid-charge characteristics are improved, but voltage mismatch occurs leading to battery deterioration
Solution Approach 1:
A voltage adjustment device is introduced as an intermediary component between the nonaqueous electrolyte battery and lead storage battery. This device actively monitors and adjusts the voltage of the nonaqueous electrolyte battery to match the flat voltage characteristics of the lead storage battery, preventing voltage mismatch while preserving rapid-charge capabilities
Solution Approach 2:
The invention dynamically changes the voltage parameter of the nonaqueous electrolyte battery through active control. By adjusting the output voltage of the nonaqueous electrolyte battery to match the lead storage battery's voltage characteristics, the system resolves the voltage mismatch issue while maintaining the high power density and rapid-charge benefits of the nonaqueous electrolyte battery
2Reliability
If the voltage of nonaqueous electrolyte battery is adjusted to match lead storage battery, then battery deterioration is reduced, but voltage stability during charge-discharge cycles becomes challenging
Solution Approach 1:
The voltage adjustment device incorporates feedback control mechanisms that continuously monitor the voltage states of both batteries and dynamically adjust the nonaqueous electrolyte battery's output voltage. This feedback system maintains voltage stability during charge-discharge cycles while preventing battery deterioration through active voltage matching
Solution Approach 2:
The system transitions from static voltage characteristics to dynamic voltage adjustment. The nonaqueous electrolyte battery's voltage is dynamically modified in real-time to match the lead storage battery's voltage profile during operation, enabling both batteries to work synergistically without voltage mismatch issues
3Speed
If nonaqueous electrolyte battery demonstrates rapid-charge-and-discharge characteristics, then charge-discharge speed is improved, but voltage between terminals changes largely causing lead storage battery deterioration
Solution Approach 1:
The voltage adjustment device serves as a mediator that decouples the high-speed charge-discharge characteristics of the nonaqueous electrolyte battery from the voltage stability requirements of the lead storage battery. It absorbs voltage fluctuations while allowing rapid current exchange, protecting the lead storage battery from deterioration
Solution Approach 2:
The invention extracts the voltage fluctuation characteristics from the nonaqueous electrolyte battery's output by using the voltage adjustment device. This separation allows the nonaqueous electrolyte battery to operate at high power density while the voltage adjustment device provides stable voltage to the lead storage battery, preventing deterioration
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 battery system achieves excellent life characteristics, safety, and rapid-charge capabilities while reducing the high cost per capacity and voltage mismatch issues, ensuring efficient charge-and-discharge cycles and prolonged battery life.
Implementation Method 1
The nonaqueous electrolyte battery includes a positive electrode and a negative electrode. The negative electrode includes a negative electrode current collector and a negative-electrode-mixture layer formed on the negative electrode current collector
Implementation Method 2
maintaining a constant open-circuit voltage and low internal resistance to mitigate voltage changes and battery deterioration
Data Source
AI summary
According to an embodiment, there is provided a battery system. The battery system includes a first battery and a second battery connected in parallel with the first battery. The first battery includes a lead storage battery. The second battery includes a nonaqueous electrolyte battery. The nonaqueous electrolyte battery includes a positive electrode and a negative electrode. The negative electrode includes a negative-electrode-mixture layer, and the negative-electrode-mixture layer contains lithium titanate. The positive electrode contains a positive electrode active material LiMn2-xM(a)xO4. A ratio of a battery capacity of the second battery to a battery capacity of the first battery is in a range of 1/133 to 1/2.