Following the Trail of Eneloop Technology

The six story FDK battery manufacturing facility located on a 4.3 acre (17,500 m2) site in Takasaki City, Japan. According to the Japanese language version of Wikipedia, it is the "only consumer NiMH battery manufacturing facility in Japan," but the underlying "evidence" of that claim (a 10/8/2011 FDK document) has been taken down from the FDK website. (Despite the missing "evidence," I do believe the claim is likely true. No one else is likely to establish any such facility in Japan. I think they would be much more likely to do so overseas.)

HISTORY
2001
Sanyo Electric Co., Ltd. acquires Toshiba Battery Co., Ltd.'s "nickel-metal hydride battery business" and forms Sanyo Energy Twicell Co., Ltd.

2010
FDK acquired Sanyo Energy Twicell Co., Ltd. and formed FDK Twicell Co., Ltd. (Although Panasonic acquired Sanyo, they could not acquire this particular Sanyo manufacturing facility due to antitrust issues.)

2014
FDK Twicell Co., Ltd. to merge with FDK CORPORATION

PATENTS
I have often recounted my understanding of the history of this facility on this forum, but I have never understood where the technology came from and where it went. I am not an attorney, much less a patent attorney, but when I saw someone else ask the question in a recent post, I decided to take a run at the matter:

First of all, I could only find three "versions" of a single patent filing by FDK Twicell Co., Ltd. on the internet. Here is the European version (EP 2690690 A1) published January 29, 2014. If you take a look at that patent, you will see that it links to CN103579591A and US20140030583 which are Chinese and USA patents with the same content. The patent is titled: "NICKEL-METAL HYDRIDE SECONDARY CELL AND NEGATIVE ELECTRODE THEREFOR" and includes some encouraging words that indicate that FDK might be continuing to improve on the original Eneloop technology.

Here are some quotes from that patent:

"One cause of self-discharge of the nickel-metal hydride secondary cell is dissociation of hydrogen, for example. Hydrogen dissociated from the hydrogen absorbing alloy of the negative electrode diffuses into the alkaline electrolyte solution, reaches the positive electrode and reduces Ni(OH)2, which is a positive electrode active material, thus causing self-discharge.

"On the other hand, one cause of shortening in the cycle life of the nickel-metal hydride secondary cell is ease of cracking of the hydrogen absorbing alloy, for example. Specifically, as hydrogen is repeatedly stored in and released from the hydrogen absorbing alloy of the negative electrode due to charging and discharging of the secondary cell, the hydrogen absorbing alloy cracks and pulverizes.

"SUMMARY OF THE INVENTION
The present invention was made in view of the above circumstances, and an object thereof is to provide a nickel-metal hydride secondary cell having high capacity and excellent in both self-discharge characteristics and cycle life characteristics."

TOSHIBA BATTERY CO LTD

I could find no pertinent Japanese patents filed by either FDK or Fujitsu, but as could be expected, I did find a large body of important(?) patents filed by Toshiba, dating from 1995 to 2002. There were so many patents that I deleted most of the "Purpose" or "Problem to be Solved" statements (which were often very similar or even identical), and attempted group them together by their "theme":



LOW SELF-DISCHARGE (LSD)
H07-057770 (1995), H07-220711 (1995), H07-220712 (1995), H07-220713 (1995) NICKEL-HYDROGEN SECONDARY BATTERY
To provide a nickel-hydrogen secondary battery which is prevented from self-discharging during preservation at high temperatures and given an extended life by having a separator whose electrolyte retention property is enhanced.
H09-082304 (1997) MANUFACTURE OF NICKEL HYDROGEN SECONDARY BATTERY
H07-282839 (1995) ACTIVATION METHOD FOR NICKEL HYDROGEN SECONDARY BATTERY
H09-167609 (1997), H10-199522 (1998), H11-162505 (1999) NICKEL-HYDROGEN BATTERY
2000-058106 MANUFACTURE OF NICKEL-HYDROGEN SECONDARY BATTERY
2000-138049 MANUFACTURE OF NICKEL-HYDROGEN SECONDARY BATTERY
2000-138050, 2000-195487 NICKEL-HYDROGEN SECONDARY BATTERY
2000-195488 MANUFACTURE OF SEPARATOR FOR BATTERY AND NICKEL-HYDROGEN SECONDARY BATTERY INCORPORATING THE SEPARATOR
2000-195542 MANUFACTURE OF NICKEL-HYDROGEN SECONDARY BATTERY
2001-273879, 2002-124243, 2002-260721, 2002-289163, 2002-289163 NICKEL HYDROGEN SECONDARY BATTERY
To provide a nickel hydrogen secondary battery which is hard to self-discharge even after a long-period storage.

LSD & CYCLES
H09-082356 (1997), H09-161842 (1997), H11-135096 (1999), 2001-148237, 2001-250530 NICKEL-HYDROGEN SECONDARY BATTERY
To provide a nickel-hydrogen secondary battery which is superior in both self-discharging characteristic and charging and discharging cycle life characteristic under high-temperature preservation.

CYCLE LIFE
09-167629 (1997), H10-069898 (1998), H10-247514 (1998), H11-097003 (1999) NICKEL HYDROGEN SECONDARY CELL
2002-270165, 2002-270166 NICKEL ELECTRODE AND NICKEL.HYDROGEN SECONDARY BATTERY WITH USAGE OF THE SAME
To provide a nickel electrode having a nickel hydroxide particle as an active material, which is often used as the active material, and a nickel.hydrogen secondary battery exhibiting excellent cycle life property where in the nickel electrode is installed.

CAPACITY
H08-236147 (1996) MANUFACTURE OF NICKEL HYDROGEN STORAGE BATTERY:
H08-255628 (1996), H11-339792 (1999), 2000-299124 NICKEL-HYDROGEN SECONDARY BATTERY
To provide a nickel-hydrogen secondary battery suppressing deterioration in capacity in a long shelf storage.

LSD, CYCLES & CAPACITY
H11-162460 (1999) NICKEL-HYDROGEN SECONDARY BATTERY
To provide a nickel-hydrogen secondary battery having a high capacity density and suppressed with the initial self-discharge of the charge/discharge cycle.
2001-256948 NICKEL/HYDROGEN SECONDARY BATTERY
To provide a nickel/hydrogen secondary battery that is superior in self-discharge property under a high-temperature environment and that also shows a high discharge capacity even at the time of high current discharge.
2000-357509, 2000-357510 MANUFACTURE OF NICKEL-HYDROGEN SECONDARY BATTERY
To provide a manufacturing method of a nickel-hydrogen secondary battery with a high allowable current value, a high capacity, and a long cycle life.
2001-217000 NICKEL-HYDROGEN SECONDARY BATTERY
To provide a nickel-hydrogen secondary battery having high active material utilizing factor, superior self-discharge characteristics in high- temperature storage, high charging efficiency under high-temperature circumstances and superior large current discharging characteristics.

DISCHARGE PERFORMANCE
H11-260396 (1999) CYLINDRICAL NICKEL HYDROGEN SECONDARY BATTERY
2000-012073 MANUFACTURE OF NICKEL-HYDROGEN SECONDARY BATTERY
2000-030702, 2000-030736, 2000-082491, 2001-006726 NICKEL-HYDROGEN SECONDARY BATTERY
2000-030699, 2000-030701, 2000-299123, 2000-306597 NICKEL-HYDROGEN SECONDARY BATTERY
To provide a nickel-hydrogen secondary battery of low internal resistance in the battery and high reliability capable of conducting high-current discharge.
2000-265228 HYDROGEN STORAGE ALLOY AND SECONDARY BATTERY
To use the hydrogen storage alloy for a secondary battery and to improve the flatness characteristic of discharge potential by providing a specific composition consisting of Mg, one or more kinds among seven elements including Li, one or more kinds among rare earth elements including Y, one or more kinds among Ca and three other elements, Ni, and one or more kinds among Co and seventeen other elements.

MANUFACTURING
H08-255629 (1996) NICKEL-HYDROGEN SECONDARY BATTERY AND MANUFACTURE THEREOF
2001-068148 NICKEL - HYDROGEN SECONDARY BATTERY
To provide a nickel - hydrogen secondary battery having a structure wherein an active material layer is filled in one surface of a conductive board of the outermost circumferential part in the negative electrode of an electrode group composed by rolling a positive electrode and the negative electrode by interlaying a separator, and the active material layers on the one surface and both surfaces have a uniform thickness.
2001-176540 NICKEL HYDROGEN SECONDARY BATTERY
To provide a nickel hydrogen secondary battery with a group of electrodes of complete round or approximately complete round, preventing cracking near winding start point of positive electrodes forming the group of electrodes.
2001-266859, 2002-252025 NICKEL/HYDROGEN SECONDARY BATTERY
To provide a nickel/hydrogen secondary battery, which is suitable for having high capacity, has high production yield by preventing poor insertion of a spiral electrode group, and secures stabilized quality by preventing a poor short circuit and shortage of an electrode mixture agent.
2002-280058, 2002-008710, 2002-252026 CYLINDRICAL NICKEL-HYDROGEN SECONDARY BATTERY
To provide a cylindrical nickel-hydrogen secondary battery capable of restricting internal short-circuiting.
2002-260647 POSITIVE ELECTRODE FOR NICKEL.HYDROGEN SECONDARY BATTERY, AND THE NICKEL.HYDROGEN SECONDARY BATTERY USING THE SAME
2002-260720 NICKEL HYDROGEN SECONDARY BATTERY
To provide a nickel hydrogen secondary battery with high utilization rate of active substance, excellent high-rate discharging characteristics which can be manufacture at low cost.

If anyone wants to take a look at these patents, they are freely available online in English. Go to this site, enter "A" (for Published patent application) as the "Kind Code" and enter the patent number. (Prior to 2000, Japanese patents used a different dating system that started with H, so the patent number will either have a 3 digit H number or a 4 digit date number as its prefix.)

SANYO ELECTRIC CO LTD

Here are the pertinent patents I located that were filed by Sanyo. It may be worth noting that these patents were issued to Sanyo Electric Co., Ltd., not to Sanyo Energy Twicell Co., Ltd.

It is also interesting that some of the previous Toshiba patents (while clearly Eneloop related) were issued to Toshiba after Sanyo acquired their NiMH battery business. (Perhaps there was some agreement regarding research in progress or patent filings for previous work which had not yet been patented. In any case, it seems likely that Sanyo had access to those patents.)


H07-262980 (1995) NICKEL-HYDROGEN STORAGE BATTERY
To obtain a battery having the excellent preservation characteristic, in which self-discharge is hard to be generated, by using nonwoven fabric, which is made of polyphenylene sulfide or the derivative thereof expressed by a specific formula, as a separator.

2002-117893 NICKEL HYDROGEN STORAGE BATTERY
To provide a nickel hydrogen battery with sufficient preservation characteristics, having a small reduction in electricity discharging capacity by self-discharging.

2002-173706 METHOD FOR TREATING HYDROGEN-STORAGE ALLOY
To provide a treatment method for obtaining a hydrogen-storage alloy having high initial activity and little self discharge for an Ni-hydrogen battery.

2003-068270 SEPARATOR FOR NICKEL/HYDROGEN STORAGE BATTERY AND NICKEL/HYDROGEN STORAGE BATTERY
To prevent the decrease of the capacity and suppress the deterioration of the charge/discharge characteristic of a nickel/hydrogen storage battery, by suppressing the occurrence of a self-discharge due to impurity ions, or of a short circuit between a positive electrode and a negative electrode due to the fine powder of a hydrogen occluding alloy passing through a separator.

2003-109657 NICKEL-HYDROGEN SECONDARY BATTERY
To provide a nickel-hydrogen secondary battery having excellent self-discharging characteristics and charging-discharging cycle life characteristics.

2004-055494 NICKEL-HYDROGEN STORAGE BATTERY
To provide a nickel-hydrogen storage battery comprising a negative electrode using a hydrogen storage alloy including aluminum capable of efficiently collecting aluminum ions dissolved in an aluminum electrolyte when charge and discharge are repeatedly conducted, and suppressing the generation of self-discharge, the reduction of a discharge capacity, or the deterioration of high-rate discharge characteristics due to the precipitation of aluminum ions in a positive electrode, and suppressing the deterioration of self-discharge characteristics due to a complexing agent becoming impurity ions moving between the positive electrode and the negative electrode in alkaline electrolyte.

2004-063168 HYDROGEN STORAGE ALLOY ELECTRODE, ITS MANUFACTURING METHOD AND ALKALINE STORAGE CELL
To restrain an inner pressure of an alkaline storage cell from rising by oxygen generated in a positive electrode at the time of overcharging or the like, restrain hydrogen storage alloy particles used for a hydrogen storage alloy electrode from being oxidized, and at the same time, to restrain the hydrogen storage alloy particles in the hydrogen storage alloy electrode from being desorbed from the hydrogen storage alloy electrode when charge and discharge are repeatedly operated, in the alkaline storage cell using as a negative electrode a hydrogen storage alloy electrode with hydrogen storage alloy particles attached to an electrode core body by a binder, and also, to obtain the alkaline storage cell having a good charge and discharge cycle property.

2004-296394 NICKEL-HYDROGEN STORAGE BATTERY AND BATTERY PACK
To provide a nickel-hydrogen storage battery which maintains high output characteristics and a low self-discharge rate for a long period by regulating a zinc volume, cobalt volume, and manganese volume precipitated in a separator.

2005-243462 SEPARATOR FOR NICKEL HYDROGEN STORAGE BATTERY AND NICKEL HYDROGEN STORAGE BATTERY USING THE SEPARATOR
To provide a sulfonated polyolefin separator for a nickel hydrogen storage battery capable of introducing a hydrophilic group to the sulfonated polyolefin separator and reducing hydrogen accumulated in a negative electrode simultaneously, and to provide a nickel hydrogen storage battery using the separator.

2007-066676 NICKEL-HYDROGEN STORAGE BATTERY
To provide a nickel-hydrogen storage battery having high capacity, excelling in a high-rate charge-discharge characteristic and excelling in a storage characteristic by suppressing self-discharge as well.

2007-149646 NICKEL METAL HYDRIDE STORAGE BATTERY
To provide nickel metal hydride storage battery that is self-discharge restrained, over a long period.

2007-149647 NICKEL HYDROGEN STORAGE BATTERY
To provide a nickel metal hydride storage battery not only with self discharge restrained over long periods of time, and moreover, with the lowering of the operating voltage restrained.

2009-108379 HYDROGEN STORAGE ALLOY, HYDROGEN STORAGE ALLOY ELECTRODE USING THE ALLOY, AND NICKEL METAL HYDRIDE BATTERY
To provide a (rare earth)-Mg-Ni based hydrogen storage alloy having excellent alkali resistance despite its high La content and low Pr and Nb contents and a hydrogen storage alloy electrode using the alloy and also to provide a nickel metal hydride battery having high capacity and long cycle life.

2012-156101 HYDROGEN-STORING ALLOY ELECTRODE FOR ALKALINE STORAGE BATTERY, AND ALKALINE STORAGE BATTERY COMPRISING THE SAME
To ensure the output stability of a nickel-metal hydride storage battery.


SANYO SPECIAL STEEL CO LTD


And, in addition, I located one patent from the Sanyo group that pertains to manufacturing of a superior Hydrogen Storage Alloy. (This may or may not have had any significance in the development of Eneloop technology, but I found it interesting.)

2003-013114 METHOD FOR MANUFACTURING HYDROGEN STORAGE ALLOY FOR NEGATIVE ELECTRODE, AND ELECTRODE
To provide a powder of hydrogen storage alloy, a method of manufacturing a negative electrode particularly for a nickel hydrogen battery, and a negative electrode for the battery using the powder as a material of the negative electrode.

Rosoku Chikara, if I haven't told you: You ROCK.

Grijon said:

Rosoku Chikara, if I haven't told you: You ROCK.

Click to expand...

THIS^^^

I have to set aside some time to REALLY let this information process. nice!

Holy crap. Awesome work is a I can say.

I'm hong to read it all when I have time.

I have to bookmark this thread to read it again and again to understand some of the principles. But this is really very informative. You're the man Rosoku!!

Thanks Rosoku Chikara!
although I have no idea what it all means.. I appreciate you taking the time to do this!
I almost wanted to say something about Toshiba.. but don`t want to go too much off-topic