# How Electric Cars Safely Pause Charging When You Want to Unplug > A system for electric vehicles that safely pauses power flow when a driver signals they want to disconnect the charging cable, preventing electrical arcing or damage. - **Patent:** US 9379564 - **Original title:** Charging control apparatus and charging control method - **Owner:** Nissan Motor Co Ltd - **Granted:** 2016 - **Status:** Active - **Times cited:** 1 - **Field:** automotive, mechanical, energy ## What it does This patent describes a safety mechanism for electric vehicles that manages the transition between charging and unplugging. When a user presses a button on the charging cable to initiate disconnection, the system pauses the flow of electricity while keeping the internal safety relays closed for a short, predetermined time. If the user changes their mind and cancels the disconnection request within that window, the car instantly resumes charging without needing a full system restart. If the time expires or the cable is physically removed, the relays open to safely cut power. ## What it does NOT cover - Does not cover the physical design of the charging plug or the locking mechanism itself. - Does not cover wireless or inductive charging systems that lack a physical cable connection. - Does not cover charging systems that immediately cut power without a pause-and-resume grace period. - Does not cover software-based battery management systems that monitor cell temperature or voltage. ## The clever bit The invention keeps the relay switches closed during the pause, treating the user's 'disconnection command' as a temporary state rather than an immediate power-off event, allowing for a seamless resume if the user accidentally hits the button or changes their mind. ## Real-world examples 1. Nissan LEAF charging systems 2. Standardized J1772 charging station protocols 3. Electric vehicle onboard charging controllers ## Why it matters Managing high-voltage power in electric vehicles is dangerous because pulling a plug while current is flowing can cause electrical arcing, which damages the charging port and the cable. This patent provides a standardized, safe 'handshake' between the user's intent to unplug and the vehicle's electrical system, ensuring the hardware is protected during the transition. ## Frequently asked questions ### What does How Electric Cars Safely Pause Charging When You Want to Unplug cover? A system for electric vehicles that safely pauses power flow when a driver signals they want to disconnect the charging cable, preventing electrical arcing or damage. ### Who owns patent US 9379564? Nissan Motor Co Ltd owns this patent, granted in 2016. ### When does this patent expire? This patent is expected to expire on June 9, 2031, when the invention enters the public domain. ### What is patent US 9379564 cited by? This patent has been cited by 1 later patents that build on its ideas. ### What problem does this patent solve? Managing high-voltage power in electric vehicles is dangerous because pulling a plug while current is flowing can cause electrical arcing, which damages the charging port and the cable. This patent provides a standardized, safe 'handshake' between the user's intent to unplug and the vehicle's electrical system, ensuring the hardware is protected during the transition. ### What does this patent NOT cover? Does not cover the physical design of the charging plug or the locking mechanism itself. **Full plain-English explainer:** https://patentbrief.org/patent/us/9379564/charging-control-apparatus-and-charging-control-method **Original patent:** https://patents.google.com/patent/US9379564 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [How Electric Cars Adjust Charging Speed to Available Power](https://patentbrief.org/patent/us/20120091953/ac-current-control-of-mobile-battery-chargers) — This patent describes how an electric vehicle's onboard charger intelligently adjusts its charging speed based on the real-time electrical power available from the wall outlet or charging station, preventing overloads and optimizing charge time. - [How an EV Charging Station Manages Power from Batteries and the Grid](https://patentbrief.org/patent/us/9168838/charging-control-system-and-charging-control-method) — This patent describes a smart charging system for electric vehicles that decides whether to power cars from a local battery or the main electricity grid, and when to recharge that local battery, to help balance power demand. - [Smart EV Charging to Protect Battery Life During Long Parking](https://patentbrief.org/patent/us/11235681/curtailing-battery-degradation-of-an-electric-vehicle-during-long-term-parking) — This patent describes a system that intelligently discharges and recharges an electric vehicle's battery while parked for a long time, like at an airport, to prevent battery damage and ensure it's ready when the owner returns, using vehicle-to-grid technology. - [How to Fast-Charge Lithium Batteries Without Damaging Them](https://patentbrief.org/patent/us/10700376/methods-for-fast-charging-and-detecting-lithium-plating-in-lithium-ion-batteries) — This patent describes a three-phase method for quickly charging lithium-ion batteries while carefully controlling voltages to prevent harmful lithium metal buildup and electrolyte damage. - [Device That Adjusts Power for Charging Multiple Devices](https://patentbrief.org/patent/us/9368994/dynamic-charging-device-and-method-thereof) — This 2016 patent describes a system that intelligently adjusts the power supplied to charge multiple devices, ensuring one device gets a steady charge while another can receive a variable amount.