How an EV Charging Station Manages Power from Batteries and the Grid
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.
Original patent title: “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. Granted to NEC in 2015 with 4 claims and 1 forward citation, and it is expected to expire in 2032.
Coverage
What does this patent actually cover?
This patent describes a system that intelligently controls how electric vehicles (EVs) are charged. It uses a "stationary rechargeable means" (like a large battery bank) alongside the main "electric power grid" to supply power. A "charging control means" decides the power source: if EV charging meets a "predetermined condition" (e.g., needing power quickly during peak grid demand), the EV gets electricity from the stationary battery. Otherwise, the EV charges directly from the grid. Simultaneously, the stationary battery itself is recharged from the grid, especially during times when fewer vehicles are charging, as determined by a "charging scheduling means." For example, a a charging station might charge EVs from its local battery during a busy afternoon, then recharge the local battery from the grid overnight when electricity is cheaper and demand is low.
The gap
What does this patent NOT cover?
- Does not cover charging systems that only draw power directly from the electric grid without using an intermediate stationary battery.
- Does not cover systems that charge electric vehicles exclusively from a stationary battery without any connection to a larger electric power grid.
- Does not cover systems where the decision to charge from the stationary battery or grid is not based on a "predetermined condition" for the vehicle's charging.
- Does not cover charging scheduling that doesn't consider both vehicle charging and stationary battery charging as part of the overall electric power demand.
- Does not cover systems that don't specifically shift stationary battery charging to times with fewer vehicles being charged.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The clever part is the dynamic decision-making for both the EV's power source and the stationary battery's recharge schedule, specifically using low-demand periods to replenish the stationary battery while using it to offload the grid during high-demand times. This optimizes grid usage and potentially reduces costs.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
EV charging stations with integrated battery storage
Fleet charging depots for electric buses or delivery vans
Smart grid energy management systems
Why it matters
The bigger picture
This patent addresses the challenge of managing electricity demand when many electric vehicles need charging. By using a stationary energy storage, it helps smooth out peak loads on the electric grid, making EV charging more efficient and potentially cheaper. This approach is important for the development of large-scale EV charging hubs and smart grids.
Filed
February 29, 2012
Granted
October 27, 2015
Market context
Who's building on this
Companies in this space
Companies like Tesla, Electrify America, EVgo, and various energy management solution providers (e.g., Siemens, ABB) are building charging infrastructure that often incorporates battery storage and smart grid integration. Utilities and energy companies are also investing in similar solutions for grid stability. NEC, the original assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →, continues to be active in energy storage and smart grid solutions.
Market impact
This patent's concepts contribute to the broader market shift towards smart charging solutions for electric vehicles. It enables more efficient use of grid resources, helps mitigate strain on local power infrastructure from EV adoption, and supports the deployment of larger, more complex charging hubs. While this specific patent has low forward citationsforward citationsLater patents that cite this one as prior art. High counts signal foundational influence.Read more →, the underlying principles of managing distributed energy resources for EV charging are fundamental to the growing EV ecosystem.
Claim 1 — Plain English
What this patent covers
This patent describes a system that intelligently controls how electric vehicles (EVs) are charged. It uses a "stationary rechargeable means" (like a large battery bank) alongside the main "electric power grid" to supply power. A "charging control means" decides the power source: if EV charging meets a "predetermined condition" (e.g., needing power quickly during peak grid demand), the EV gets electricity from the stationary battery. Otherwise, the EV charges directly from the grid. Simultaneously, the stationary battery itself is recharged from the grid, especially during times when fewer vehicles are charging, as determined by a "charging scheduling means." For example, a a charging station might charge EVs from its local battery during a busy afternoon, then recharge the local battery from the grid overnight when electricity is cheaper and demand is low.
The clever bit
The clever part is the dynamic decision-making for both the EV's power source and the stationary battery's recharge schedule, specifically using low-demand periods to replenish the stationary battery while using it to offload the grid during high-demand times. This optimizes grid usage and potentially reduces costs.
What it does not cover
- Does not cover charging systems that only draw power directly from the electric grid without using an intermediate stationary battery.
- Does not cover systems that charge electric vehicles exclusively from a stationary battery without any connection to a larger electric power grid.
- Does not cover systems where the decision to charge from the stationary battery or grid is not based on a "predetermined condition" for the vehicle's charging.
- Does not cover charging scheduling that doesn't consider both vehicle charging and stationary battery charging as part of the overall electric power demand.
- Does not cover systems that don't specifically shift stationary battery charging to times with fewer vehicles being charged.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
PatentBrief Score
Impact Score
Limited data
Citation count
6/40
Early citations
Claim breadth
3/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
5/20
Granted 10–20 years ago
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$15K – $48K
Midpoint $30K · 5.6 yr remaining · industry ×0.9
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
The original legal language
Original claims
4 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Kudo, K., Yano, H., & Kuribayashi, R. (2015). How an EV Charging Station Manages Power from Batteries and the Grid (U.S. Patent No. 9,168,838). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/9168838/charging-control-system-and-charging-control-method
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How an EV Charging Station Manages Power from Batteries and the Grid cover?
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.
Who owns patent US 9168838?
NEC owns this patent, granted in 2015.
When does this patent expire?
This patent is expected to expire on February 29, 2032, when the invention enters the public domain.
What is patent US 9168838 cited by?
This patent has been cited by 1 later patents that build on its ideas.
What problem does this patent solve?
This patent addresses the challenge of managing electricity demand when many electric vehicles need charging. By using a stationary energy storage, it helps smooth out peak loads on the electric grid, making EV charging more efficient and potentially cheaper. This approach is important for the development of large-scale EV charging hubs and smart grids.
What does this patent NOT cover?
Does not cover charging systems that only draw power directly from the electric grid without using an intermediate stationary battery.
Patent monitoring