Module Bypass Switch for Battery Pack Balancing
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Solution Overview
Problem
Conventional battery pack systems face challenges in inter-module balancing, leading to safety hazards due to heat generation and prolonged downtime when replacing modules, as existing solutions like bypass switches with resistors consume power and generate heat, and balancing processes take days or weeks.
Innovation Solution
Incorporating a module bypass switch, charge switch, and discharge switch within each battery pack system module to allow for rapid inter-module balancing by diverting charge and discharge currents without power dissipation, reducing heat and enabling faster balancing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bypass switch with a resistor is used to short out a battery pack system module for inter-module balancing, then the balancing function is achieved, but power is consumed and heat is generated through Joule heating
Solution Approach 1:
The patent extracts and removes the resistor component from the bypass switch circuit. By eliminating the resistor, the system achieves bypass functionality without Joule heating, thus removing the source of harmful heat generation while maintaining the inter-module balancing capability.
Solution Approach 2:
The patent converts the harmful effect of resistance into a benefit by using ideal switches (transistors) with near-zero on-resistance. This transformation allows the bypass function to operate without significant power dissipation, turning the potential harm of current flow into a beneficial low-loss operation.
2Reliability
If a resistor is coupled in series with the bypass switch to prevent short circuiting, then safety is improved, but power consumption and heat generation occur
Solution Approach 1:
The patent extracts and removes the series resistor from the bypass circuit. Instead of using a resistor to limit current, the system employs control logic that activates the bypass switch only when necessary and uses the inherent low on-resistance of the switch itself, eliminating continuous power consumption.
Solution Approach 2:
The bypass switch itself provides the short circuit protection function through its controlled operation. The switch is designed to handle the full current when activated, and the control system ensures it operates only when needed, making the switch self-sufficient for both bypass and protection functions without requiring an external resistor.
3Reliability
If conventional balancing processes are used for replacement modules, then the modules are balanced, but the process takes days or weeks resulting in prolonged downtime
Solution Approach 1:
The patent implements preliminary action by pre-charging replacement modules to a voltage close to the operating voltage before installation. This preliminary charging reduces the time required for post-installation balancing, allowing the module to become operational much faster than conventional methods that start from a fully discharged state.
Solution Approach 2:
The patent rushes through the balancing process by using a dedicated pre-charge circuit that applies higher current initially to quickly bring the replacement module up to voltage, then transitions to normal charging. This skipping of the slow initial charging phase reduces balancing time from days or weeks to hours or minutes.
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 solution reduces safety hazards and downtime by enabling rapid inter-module balancing, extending the life of battery pack system modules and reducing replacement costs, as balancing is achieved in hours rather than days or weeks.
Implementation Method 1
the resistor 120 consumes power and generates heat in the system 100 through Joule heating
Data Source
AI summary
A battery pack system module may include a module bypass switch for allowing charge current to bypass the battery pack system module. A charge switch and a discharge switch may be coupled with the module bypass switch. When other battery pack system modules are coupled in series with the module, balancing between modules may be achieved by allowing charge current to bypass the unbalanced modules and charge other modules. For example, when an unbalanced module is at a higher level of charge than other modules, a charge switch and a discharge switch in the unbalanced module de-activate and a module bypass switch activates to allow charge current to rapidly bring other modules into balance. The discharge switch and the charge switch allow the charging current to bypass the unbalanced module creating little or no additional heat dissipation.