High Voltage Battery Pack Direct AC Interface
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Solution Overview
Problem
Existing battery packs for onsite power generation systems suffer from efficiency losses due to the need for transformers and DC/DC converters, which result in significant power losses during charging and discharging processes.
Innovation Solution
A high-voltage battery pack configuration that eliminates the need for an intervening DC/DC converter and transformer by using high-speed current detection circuits and switches to directly provide the battery voltage to the AC stage, while employing high-speed switches and sensors for fault protection to prevent over-current and surge-current conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If transformers and DC/DC converters are used to interface battery modules with AC stage, then galvanic isolation and voltage matching are achieved, but significant power losses occur during charging and discharging
Solution Approach 1:
The patent removes the DC/DC converter and transformer from the battery pack interface by designing the battery modules to directly output AC voltage compatible with the AC stage, eliminating the power lossy conversion stages while maintaining galvanic isolation through alternative means
Solution Approach 2:
The battery modules are designed to perform multiple functions simultaneously: energy storage, voltage generation at AC-compatible levels, and direct AC stage interfacing, replacing what previously required separate DC/DC conversion and transformation stages
2Quantity of substance
If high-voltage lithium-ion battery packs are used to increase energy density and operating voltage, then storage capacity per unit mass improves, but charging and discharging power losses from transformers and DC/DC converters remain significant
Solution Approach 1:
The patent extracts and removes the problematic DC/DC converter and transformer components that caused power losses, allowing high-voltage lithium-ion battery packs to directly interface with the AC stage without efficiency penalties
3Device complexity
If battery module voltage is made equivalent to commercial AC power source voltage, then transformers and DC/DC converters can be omitted, but fault protection against over-current and surge-current becomes more challenging
Solution Approach 1:
The patent implements preliminary protective measures by placing fast-acting circuit breakers and current protection circuits directly at the battery module output before AC stage connection, enabling rapid response to over-current and surge-current faults before they can damage the system
Solution Approach 2:
The patent introduces protective intermediary devices (fast-acting circuit breakers, current limiters) between the battery modules and AC stage that mediate fault conditions, allowing direct voltage interfacing while maintaining system reliability through rapid fault isolation
Data Source
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AI summary
A high-voltage battery pack for an onsite power generation system includes battery modules configured to provide a voltage of at least 170V. High-speed switches and a high-speed current detection circuit are serially coupled between the battery modules and the positive and negative output terminals of the battery pack. A control circuit is operatively coupled to the current detection circuit so that when the current detection circuit detects a fault condition, the control circuit opens one or more of the switches to thereby electrically isolate the battery modules from the positive and negative output terminals of the battery pack. The battery pack is configured so that the at least 170V provided by the battery modules can be provided to an AC stage of the onsite power generation system without an intervening DC/DC converter and/or a transformer.