How to Grade Used Batteries for a Second Life
This patent describes a system that reads electrical characteristics and usage history from a rechargeable battery module to determine if it's good enough to be used again for a different purpose, like energy storage.
Original patent title: “Secondary battery module, battery information management device, battery information management system, secondary battery reuse system, secondary battery recovery and sales system, secondary battery reuse method, and secondary battery recovery and sales method”
This patent describes a system that reads electrical characteristics and usage history from a rechargeable battery module to determine if it's good enough to be used again for a different purpose, like energy storage. Granted to Hitachi Automotive Systems in 2016 with 33 claims and 4 forward citations, and it is expected to expire in 2032.
Coverage
What does this patent actually cover?
This patent describes a system for managing rechargeable batteries, called 'secondary battery modules.' Each battery module stores its own 'electrical characteristic information' (like its original capacity and how much it resists current) and 'usage history information' (like its voltage and current ranges over time) (ClaimclaimA numbered sentence at the end of a patent that legally defines what the inventor owns. The most important section.Read more → 1). A 'battery information management device' connects to these modules, reads this stored data, and then compares it to a 'predetermined threshold' (Claim 1). If the battery's information meets the threshold, the device 'grades' it as suitable for 'reuse,' meaning it can be used for something else after its first life, perhaps in an electric vehicle (Claim 1). For example, a device could read data from an old electric car battery, see its remaining capacity is above a certain level, and then grade it for use in a home solar power storage system.
The gap
What does this patent NOT cover?
- Does not cover managing primary (single-use) batteries, only 'secondary battery modules' that are rechargeable.
- Does not cover battery management systems that only monitor battery health without explicitly grading for 'reuse' based on predetermined thresholds.
- Does not cover systems where battery characteristic and usage history information is not stored directly within the 'secondary battery module' itself.
- Does not cover grading systems that do not use specific 'electrical characteristic information' and 'usage history information' as claimed.
- Does not cover systems that simply charge or discharge batteries without reading and grading their internal information for reuse.
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 combining on-board storage of detailed battery history with a centralized system that specifically grades these batteries for 'reuse' against predefined limits. This allows for an automated and standardized way to assess a battery's suitability for a second life, rather than just discarding it.
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
Nissan LEAF second-life battery projects
Tesla Powerwall (though not necessarily using this patent, it represents the market for repurposed batteries)
Energy storage systems for commercial buildings using retired EV batteries
Grid-scale battery storage solutions
Why it matters
The bigger picture
As electric vehicles become more common, there will be a growing number of used EV batteries. This patent addresses the challenge of figuring out which of these batteries still have enough life left to be repurposed for other uses, like storing energy from solar panels or powering homes. By providing a structured way to assess battery health for reuse, it supports the development of a 'second-life' battery market, reducing waste and making better use of valuable resources.
Filed
September 14, 2012
Granted
July 19, 2016
Market context
Who's building on this
Companies in this space
Hitachi Automotive Systems Ltd, the original assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →, is active in automotive components, including battery management. Other companies like Nissan, Tesla, and various energy storage solution providers are actively exploring and implementing second-life battery applications. Startups focused on battery diagnostics and repurposing, such as Relectrify or B2U Storage, are also operating in this space.
Market impact
This patent contributes to the emerging market for second-life batteries, particularly from electric vehicles. By providing a framework for systematically assessing and grading used batteries, it helps enable new business models for battery reuse, reducing the environmental impact of battery disposal and creating new value streams. It supports the growth of stationary energy storage solutions by making a supply of cost-effective, repurposed batteries available, which can help integrate renewable energy sources into the grid.
Claim 1 — Plain English
What this patent covers
This patent describes a system for managing rechargeable batteries, called 'secondary battery modules.' Each battery module stores its own 'electrical characteristic information' (like its original capacity and how much it resists current) and 'usage history information' (like its voltage and current ranges over time) (Claim 1). A 'battery information management device' connects to these modules, reads this stored data, and then compares it to a 'predetermined threshold' (Claim 1). If the battery's information meets the threshold, the device 'grades' it as suitable for 'reuse,' meaning it can be used for something else after its first life, perhaps in an electric vehicle (Claim 1). For example, a device could read data from an old electric car battery, see its remaining capacity is above a certain level, and then grade it for use in a home solar power storage system.
The clever bit
The clever part is combining on-board storage of detailed battery history with a centralized system that specifically grades these batteries for 'reuse' against predefined limits. This allows for an automated and standardized way to assess a battery's suitability for a second life, rather than just discarding it.
What it does not cover
- Does not cover managing primary (single-use) batteries, only 'secondary battery modules' that are rechargeable.
- Does not cover battery management systems that only monitor battery health without explicitly grading for 'reuse' based on predetermined thresholds.
- Does not cover systems where battery characteristic and usage history information is not stored directly within the 'secondary battery module' itself.
- Does not cover grading systems that do not use specific 'electrical characteristic information' and 'usage history information' as claimed.
- Does not cover systems that simply charge or discharge batteries without reading and grading their internal information for reuse.
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
Early stage
Citation count
14/40
Early citations
Claim breadth
20/20
Very broad protection
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
$59K – $188K
Midpoint $118K · 6.1 yr remaining · industry ×1.4
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
33 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Emori, A., Yamauchi, S., & Kawahara, Y. (2016). How to Grade Used Batteries for a Second Life (U.S. Patent No. 9,397,374). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/9397374/secondary-battery-module-battery-information-management-device-battery-informati
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
Embed
Add this patent to your site
Drop this plain-English patent card into any blog post or article — free, no signup. It always links back to the full breakdown here.
<div data-patentlens-widget data-patent-number="US9397374"></div> <script src="https://patentbrief.org/embed.js" async></script>
Stay in the loop
Get a weekly digest of new patents.
One email per week. No spam. Unsubscribe anytime.
Keep exploring
Related patents you should know
US 4683195 · 1987
How to Make Billions of Copies of a DNA Segment
This patent describes the Polymerase Chain Reaction (PCR), a method to rapidly create many copies of a specific piece of DNA or RNA, enabling its detection and analysis.
Cetus Corp
US 8697359 · 2014
How to Edit Genes in Human Cells Using an Engineered CRISPR System
This patent describes an engineered CRISPR-Cas9 system for precisely cutting DNA in eukaryotic cells to change how genes work, opening the door for gene editing in complex organisms.
Massachusetts Institute of Technology
US 7657849 · 2010
How the iPhone's Slide-to-Unlock Gesture Works
Apple's 2010 patent describes unlocking a device by dragging a specific graphical image across the touchscreen along a predefined path, a gesture that became iconic with the original iPhone.
Apple Inc
US 4733665 · 1988
How Doctors Implant a Permanent Stent Using a Balloon
This patent describes the method for placing a permanent, expandable wire mesh tube inside a blood vessel or other body tube using a balloon-tipped catheter to widen it and keep it open.
Expandable Grafts Partnership
US 4965188 · 1990
How to Make Many Copies of a DNA Piece with Heat
This patent describes the Polymerase Chain Reaction (PCR) method, a technique to make millions of copies of a specific DNA segment using a heat-resistant enzyme and repeated temperature changes.
Cetus Corp
US 4235871 · 1980
How to Encapsulate Active Materials in Lipid Bubbles Efficiently
This patent describes a method for trapping biologically active substances inside tiny, multi-layered fat bubbles called liposomes, using a specific water-in-oil emulsion and gel-forming process to improve how much material gets captured.
Individual
Semantically similar
You might also find these interesting
US 20240186800 · Mirai Labo Co
How a System Tracks and Transfers Rechargeable Batteries Between Users
US 9168838 · 2015 · NEC
How an EV Charging Station Manages Power from Batteries and the Grid
US 11235681 · 2022 · Inventus Holdings
Smart EV Charging to Protect Battery Life During Long Parking
US 10700376 · 2020 · GM Global Technology Operations
How to Fast-Charge Lithium Batteries Without Damaging Them
More to explore
More in Energy & Clean Tech
US RE49155 · 2022 · Halliburton Energy Services Inc
Electric or Natural Gas Blending and Pumping for Oil Wells
US 11436484 · 2022 · Nvidia Corp
Nvidia's Method for Training Self-Driving Car AI in Simulations
US 11840398 · 2023 · Titan Trailers Inc
How Titan Trailers Builds Stronger, Smoother Cargo Containers
US 2708656 · 1955
How the First Nuclear Reactor Works
New to patents?
Common Questions
Frequently Asked Questions
What does How to Grade Used Batteries for a Second Life cover?
This patent describes a system that reads electrical characteristics and usage history from a rechargeable battery module to determine if it's good enough to be used again for a different purpose, like energy storage.
Who owns patent US 9397374?
Hitachi Automotive Systems owns this patent, granted in 2016.
When does this patent expire?
This patent is expected to expire on September 14, 2032, when the invention enters the public domain.
What is patent US 9397374 cited by?
This patent has been cited by 4 later patents that build on its ideas.
What problem does this patent solve?
As electric vehicles become more common, there will be a growing number of used EV batteries. This patent addresses the challenge of figuring out which of these batteries still have enough life left to be repurposed for other uses, like storing energy from solar panels or powering homes. By providing a structured way to assess battery health for reuse, it supports the development of a 'second-life' battery market, reducing waste and making better use of valuable resources.
What does this patent NOT cover?
Does not cover managing primary (single-use) batteries, only 'secondary battery modules' that are rechargeable.
Patent monitoring