# How a Car Battery Charges from High-Voltage Stations Using a Capacitor > This patent describes a vehicle power system that uses a capacitor in series with a lower-voltage battery to allow charging from standard electric vehicle charging stations that supply a higher minimum voltage. - **Patent:** US 11351876 - **Original title:** Vehicle power supply system - **Owner:** Mazda Motor - **Granted:** 2022 - **Status:** Active - **Times cited:** 0 - **Field:** automotive, consumer_electronics, energy ## What it does The patent details a vehicle power supply system designed to charge from an electric vehicle (EV) charging station that provides a voltage at or above a certain minimum, like 50 volts (Claim 2). The system includes a battery with a rated voltage lower than this minimum, for example, 48 volts (Claim 5). To bridge this voltage gap, a capacitor is connected in series with the battery (Claim 1). The combined rated voltage of the battery and capacitor together is higher than the charging station's minimum voltage. For instance, a 48V battery combined with a 72V capacitor (Claim 4) creates a 120V series, allowing it to interface with a 50V or higher charging station. The system's circuitry then manages the power received from the charging station to charge both the battery and the capacitor (Claim 1). An example of usage would be a mild-hybrid vehicle with a 48V battery system being able to use a public EV fast charger designed for higher voltage full EVs. ## What it does NOT cover - Does not cover vehicle power systems where the battery's rated voltage is already equal to or greater than the charging station's lower limit voltage (Claim 1). - Does not cover systems where the capacitor is not electrically connected in series with the battery during charging (Claim 1). - Does not cover systems where the combined rated voltage of the battery and capacitor is less than or equal to the charging station's lower limit voltage (Claim 1). - Does not cover systems that only use a battery or only a capacitor for energy storage, without the series combination (Claim 1). - Does not cover charging systems that do not receive power from an external EV charging station (Claim 1). ## The clever bit The clever bit is using a capacitor in series with a lower-voltage battery to effectively 'boost' the perceived voltage for the charging station, making the combined unit compatible with higher-voltage charging infrastructure without requiring a complex, high-power DC-DC converter for the entire charging path. ## Real-world examples 1. Mild-hybrid vehicles with 48V electrical systems 2. Vehicles designed to charge from public EV charging stations with non-standard battery voltages 3. Future Mazda mild-hybrid or plug-in hybrid models ## Why it matters This patent addresses a challenge for vehicles that use lower voltage battery systems, such as 48V mild-hybrids, which typically cannot directly use public EV charging infrastructure designed for higher voltage full electric vehicles. By enabling these vehicles to interface with standard EV charging stations, it could expand their charging options and convenience. This could be particularly relevant for Mazda, the assignee, as they have explored mild-hybrid technologies. ## Frequently asked questions ### What does How a Car Battery Charges from High-Voltage Stations Using a Capacitor cover? This patent describes a vehicle power system that uses a capacitor in series with a lower-voltage battery to allow charging from standard electric vehicle charging stations that supply a higher minimum voltage. ### Who owns patent US 11351876? Mazda Motor owns this patent, granted in 2022. ### When does this patent expire? This patent is expected to expire on January 27, 2040, when the invention enters the public domain. ### What problem does this patent solve? This patent addresses a challenge for vehicles that use lower voltage battery systems, such as 48V mild-hybrids, which typically cannot directly use public EV charging infrastructure designed for higher voltage full electric vehicles. By enabling these vehicles to interface with standard EV charging stations, it could expand their charging options and convenience. This could be particularly relevant for Mazda, the assignee, as they have explored mild-hybrid technologies. ### What does this patent NOT cover? Does not cover vehicle power systems where the battery's rated voltage is already equal to or greater than the charging station's lower limit voltage (Claim 1). **Full plain-English explainer:** https://patentbrief.org/patent/us/11351876/vehicle-power-supply-system **Original patent:** https://patents.google.com/patent/US11351876 --- _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: - [High-Power Electric Vehicle Charging with Pulsed Current from the Grid](https://patentbrief.org/patent/us/20180339601/charging-station-system-and-method) — This patent describes a system for rapidly charging electric vehicles using high-voltage grid power and a unique 'pulse current' method that can also automatically park the car. - [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. - [Smart Charging for Nickel-Zinc Batteries in Hybrid Power Systems](https://patentbrief.org/patent/us/10967755/controlling-battery-states-of-charge-in-systems-having-separate-power-sources) — This patent describes a method for precisely controlling the charge of aqueous nickel-zinc batteries in systems like hybrid vehicles or uninterruptible power supplies, using a separate main power source to switch between full and lower 'float' charge states. - [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 Charging for Electric Vehicle Batteries Based on Chemistry and Use](https://patentbrief.org/patent/us/11027624/electric-vehicle-charging-by-adjusting-charger-current-based-on-battery-chemistr) — This patent describes a method for electric vehicle charging stations to adjust how fast they charge a battery based on its specific chemical type, its current charge level, and even how many passengers are on board.