Power Storage Voltage Equalization by Load Change
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Power storage devices, such as lithium ion batteries, exhibit individual differences in self-discharge current and voltage due to varying internal resistances, leading to inconsistent component voltages over time and temperature, making it challenging to maintain uniform voltage levels during production, testing, and usage.
Innovation Solution
A method to adjust the device voltage of power storage devices by changing the load applied, allowing the component voltage to lower when the load is reduced and rise when increased, without charging or discharging the device, enabling voltage equalization to a reference voltage without altering the state of charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional charging or discharging methods are used to adjust battery voltage, then the battery voltage can be changed to a desired magnitude, but the state of charge is altered and additional time is required for charging/discharging cycles
Solution Approach 1:
The invention changes the load applied to the battery instead of charging or discharging it. By varying the load from a first load to a second load, the component voltage changes due to the battery's internal characteristics (self-discharge current and resistance), achieving voltage adjustment without altering the state of charge. This parameter change approach eliminates the time-consuming charging/discharging cycles while maintaining precise voltage control.
2Manufacturing precision
If conventional charging or discharging methods are used to adjust battery voltage, then the battery voltage can be changed to a desired magnitude, but the state of charge is altered
Solution Approach 1:
The invention changes the load parameter applied to the battery rather than changing the charge state. By adjusting the load magnitude, the component voltage is modified through the battery's internal resistance and self-discharge characteristics, achieving precise voltage control while preserving the original state of charge. This approach separates voltage control from charge state alteration.
3Stability of the object's composition
If batteries are charged to the same component voltage, then initial voltage uniformity is achieved, but individual differences in self-discharge current cause voltage divergence over time and temperature changes
Solution Approach 1:
The invention utilizes the battery's own self-discharge characteristics and internal resistance to adjust its voltage. By applying different loads, the battery's component voltage changes in a predictable manner based on its individual properties (self-discharge current ID and resistance Rp). This self-service approach accounts for individual differences between batteries, as each battery responds according to its unique characteristics, maintaining voltage uniformity without requiring external charging/discharging operations that could introduce additional variations.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In a method for adjusting a device voltage (VB) of a power storage device (1), when this device is represented as an equivalent circuit (Ec) in which a parallel circuit (Pc) of a capacitive device component (1B) and a short-circuit resistance (Rp) indicating a magnitude of self-discharge of the device component (1B) is connected in series with a DC resistance (Rs) of the power storage device (1), the power storage device (1) has a property that, while the power storage device (1) is pressed under a load (BL) and the device component (1B) is charged to generate a component voltage (VBB), the component voltage (VBB) lowers when the load (BL) is reduced, but rises when the load (BL) is increased. The method includes a) component-voltage changing by load change (S8, S19, S24, S33) of changing the load (BL) applied to the power storage device (1) under a first load (BL1), generating a first component voltage (VBB1) in the device component (1B), from the first load (BL1) to change the component voltage (VBB) from the first component voltage (VBB1).