JPH10302765A - Lithium secondary battery - Google Patents
Lithium secondary batteryInfo
- Publication number
- JPH10302765A JPH10302765A JP9113001A JP11300197A JPH10302765A JP H10302765 A JPH10302765 A JP H10302765A JP 9113001 A JP9113001 A JP 9113001A JP 11300197 A JP11300197 A JP 11300197A JP H10302765 A JPH10302765 A JP H10302765A
- Authority
- JP
- Japan
- Prior art keywords
- lithium
- graphite
- electrode
- secondary battery
- lithium secondary
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、リチウム二次電
池、特にその負極に関する。The present invention relates to a lithium secondary battery, and more particularly to a negative electrode thereof.
【０００２】[0002]
【従来の技術】パーソナルコンピュータ、携帯電話等の
ポータブル機器の開発にともない、その電源として電池
の需要は非常に大きくなっている。リチウム二次電池
は、高エネルギー密度を得ることができ、特に正極にコ
バルト酸リチウム、負極に炭素材料を用いたいわゆるリ
チウムイオン電池が現在ではポータブル機器の電源とし
て広範囲に用いられるに至っている。ポータブル機器の
小型軽量化が進むにつれて、電池の高エネルギー密度化
に対する要望も益々高まってきており、さらに高いエネ
ルギー密度を有する新規電極材料の出現が望まれてい
る。近年、リチウムを含む窒素化合物、すなわちリチウ
ム含有複合窒化物がリチウム二次電池用の負極材料とし
て研究され始めた。従来、リチウムの窒化物としては、
固体電解質である窒化リチウム（Ｌｉ3Ｎ）がよく研究
されてきた。この材料は、イオン伝導性はあるが電子伝
導性がないため、活物質としてではなく電解質として研
究されてきた。ところが、最近、Ｌｉ3ＮのＬｉの一部
を他の金属成分で置換することにより電子伝導性を付与
することができ、これによりこの種の窒素化合物も電極
活物質として作用することがわかってきた。2. Description of the Related Art With the development of portable devices such as personal computers and mobile phones, the demand for batteries as power sources has become extremely large. A lithium secondary battery can obtain a high energy density. In particular, a so-called lithium ion battery using lithium cobalt oxide for a positive electrode and a carbon material for a negative electrode has been widely used as a power source of a portable device at present. As portable devices have become smaller and lighter, the demand for higher energy density of batteries has been increasing, and the appearance of new electrode materials having higher energy density has been desired. In recent years, nitrogen compounds containing lithium, that is, lithium-containing composite nitrides, have been studied as negative electrode materials for lithium secondary batteries. Conventionally, as lithium nitride,
Lithium nitride (Li 3 N), a solid electrolyte, has been well studied. This material has been studied as an electrolyte, not as an active material, because it has ionic conductivity but no electronic conductivity. However, recently, it has been found that by substituting a part of Li of Li 3 N with another metal component, electron conductivity can be imparted, whereby this type of nitrogen compound also acts as an electrode active material. Was.
【０００３】Ｌｉ3ＮのＬｉの一部を他の金属成分で置
換したリチウム含有複合窒化物と呼ばれるこの種の材料
に関しては、古くはV.W.Sachsze,et al., Z.Anorg.Che
m.(1949)やT.Asai,et al.,Mat.Res.Bull.vol.16(1984)
に報告されている。しかし、電池用活物質材料としての
検討は始まったばかりで、最近になって、Ｌｉ3ＮのＬ
ｉの一部をＦｅで置換したＬｉ3ＦｅＮ2(M.Nishijima,e
t al.,J.Solid State Chem.vol.113,(1994))、Ｌｉ3Ｎ
のＬｉの一部をＭｎで置換したＬｉ7ＭｎＮ4（M.Nishij
ima,et al.,J.Electrochem.Soc.Vol.141(1994))、Ｌｉ3
ＮのＬｉの一部をＣｏ置換したＬｉ3-xＣｏxＮ(M.Nishi
jima,et al.,Solid State Ionics vol.83(1996),同じく
T.Shoudai,et al.,Solid State Ionics vol.86〜88 p78
5(1996))などが報告されているにすぎない。従って、こ
の種のリチウム含有複合窒化物の電池材料としての報告
例は多くはないが、上記報告例にもあるようにその電池
材料としてのプロファイルは以下の通りである。A material of this kind called a lithium-containing composite nitride in which a part of Li of Li 3 N is replaced by another metal component has been used for a long time in VWSachsze, et al., Z. Anorg.
m. (1949) and T. Asai, et al., Mat. Res. Bull. vol. 16 (1984)
Has been reported to. However, the study as an active material for batteries has just begun, and recently, the L 3 N
Li 3 FeN 2 (M. Nishijima, e
t al., J. Solid State Chem. vol. 113, (1994)), Li 3 N
Li 7 MnN 4 (M. Nishij
ima, et al., J. Electrochem. Soc. Vol. 141 (1994)), Li 3
Li 3-x Co x N (M. Nishi
jima, et al., Solid State Ionics vol.83 (1996), also
T. Shodai, et al., Solid State Ionics vol.86-88 p78
5 (1996)). Therefore, although there are not many reports of this kind of lithium-containing composite nitride as a battery material, as described in the above reports, the profile of the battery material is as follows.
【０００４】この種の化合物は、正極にも負極にも用い
ることができるが、電位的にはＬｉ基準で０〜２Ｖ辺り
にその作動電位があるため、負極に用いる方が適してい
る。例えば、負極として用いるならば、リチウムイオン
電池に用いられている炭素材料負極に比べて相対的に貴
にあるため、電池電圧は低くなる。ところが、電気化学
的に吸蔵・放出しうるリチウム量は炭素材料より大きく
なる。すなわち、電池電圧は低くなるが、高容量が期待
できるリチウム二次電池用負極材料である。[0004] This type of compound can be used for both the positive electrode and the negative electrode, but it is more suitable to use it for the negative electrode because its operating potential is around 0 to 2 V on the basis of Li. For example, when used as a negative electrode, the battery voltage is lower because it is relatively noble as compared with a carbon material negative electrode used in a lithium ion battery. However, the amount of lithium that can be inserted and released electrochemically is larger than that of a carbon material. That is, it is a negative electrode material for a lithium secondary battery that can be expected to have a high capacity although the battery voltage is low.
【０００５】[0005]
【発明が解決しようとする課題】本発明者らは、Ｌｉ3
ＮのＬｉの一部を他の金属成分で置換したリチウム含有
複合窒化物をいくつか合成し、その電極活物質としての
評価試験を行った結果、電子伝導性が付与されたといっ
ても十分ではなく、電極材料として使用する場合は導電
剤を加えて極板とする必要があることがわかった。上述
の報告では、導電剤としてアセチレンブラックを用いて
作製した電極で充放電試験を行い、好結果を得ていた。
典型的な例として、 この種の化合物の中でもＣｏ置換
した一般式Ｌｉ3-xＣｏxＮで表される化合物について検
討を加えてみた。この時も導電剤としてアセチレンブラ
ックを用い、結着剤樹脂としてはテフロンを用いて極板
を作製した。この窒素化合物への電気科学的なＬｉの吸
蔵・放出を繰り返してその可逆性を検討したところ、基
本的に高容量で高い可逆性を示す電極材料となることが
わかった。SUMMARY OF THE INVENTION The present inventors have proposed Li 3
As a result of synthesizing some lithium-containing composite nitrides in which a part of Li of N was replaced by other metal components and conducting an evaluation test as an electrode active material, it is not sufficient even if electron conductivity is given. In addition, it was found that when used as an electrode material, it was necessary to add a conductive agent to form an electrode plate. In the above-mentioned report, a charge / discharge test was performed on an electrode manufactured using acetylene black as a conductive agent, and good results were obtained.
As a typical example, among such compounds, a compound represented by the general formula Li 3-x Co x N substituted with Co was examined. At this time, an electrode plate was prepared using acetylene black as the conductive agent and Teflon as the binder resin. When the electrochemical reversibility of the insertion and extraction of Li into and from the nitrogen compound was repeated and the reversibility was examined, it was found that the electrode material was basically a high capacity and highly reversible electrode material.
【０００６】ところが、実際の使用を想定した種々の評
価を行った結果、中でも充放電を高温で行うと問題が発
生した。これは、高温の環境下で充放電を行った場合
に、充放電効率が著しく低下することである。例えば、
通常の使用温度域である６０℃の環境下でも、その充放
電効率（この場合はＬｉ吸蔵の電気量を充電電気量、Ｌ
ｉ放出の電気量を放電電気量と設定した）は平均して９
５％程度となった。そして、サイクルの進行に伴って著
しい容量の劣化が確認された。これは、各サイクルの充
電で５％分の電気量が充電反応以外の反応で消費された
ことを意味する。この充電反応以外の反応は、おそらく
電解液の分解反応であると予想される。また、その他の
リチウム含有複合窒化物、例えばＬｉαＭβＮ（Ｍ:遷
移金属）でその組成式を表した場合のＭがＣｏ以外の遷
移金属の場合や、またその遷移金属の添加量（βに相
当）を変えて合成した材料についても試験を行ったが、
いずれの場合も同様の劣化現象が見られた。この問題を
解決しない限り、この種の化合物を電極に用いた電池は
実用に耐えない。[0006] However, as a result of performing various evaluations assuming actual use, problems have arisen particularly when charging and discharging are performed at a high temperature. This means that when charging and discharging are performed in a high-temperature environment, the charging and discharging efficiency is significantly reduced. For example,
Even in an environment of 60 ° C., which is a normal operating temperature range, the charge / discharge efficiency (in this case, the amount of Li occlusion is converted to the amount of charge, L
The amount of electricity emitted from i was set as the amount of electricity discharged.
It was about 5%. Then, a remarkable deterioration of the capacity was confirmed with the progress of the cycle. This means that 5% of the amount of electricity was consumed in reactions other than the charging reaction in each cycle of charging. The reactions other than the charging reaction are probably expected to be decomposition reactions of the electrolytic solution. In addition, when M is a transition metal other than Co when the composition formula is represented by other lithium-containing composite nitrides, for example, LiαMβN (M: transition metal), or the amount of the transition metal added (corresponding to β) Tests were also conducted on materials synthesized by changing
In each case, a similar deterioration phenomenon was observed. Unless this problem is solved, a battery using such a compound for an electrode is not practical.
【０００７】[0007]
【課題を解決するための手段】本発明のリチウム二次電
池は、少なくとも一方の電極が、式ＬｉαＭβＮ（Ｍは
遷移金属であり、αは窒素１原子当たりのリチウムの原
子数比、βは窒素１原子当たりのＭの原子数比であ
る。）で表されるリチウム含有複合窒化物を電極活物質
として含み、かつ黒鉛を含むことを特徴とする。According to the lithium secondary battery of the present invention, at least one electrode has the formula LiαMβN (M is a transition metal, α is the ratio of the number of lithium atoms per nitrogen atom, and β is the nitrogen atom ratio). It is characterized by containing a lithium-containing composite nitride represented by the following formula (1) as an electrode active material and graphite.
【０００８】ここで、β値は、０．１≦β≦０．８の範
囲が適当である。また、遷移金属Ｍは、コバルト（Ｃ
ｏ）、鉄（Ｆｅ）、マンガン（Ｍｎ）、銅（Ｃｕ）、お
よびニッケル（Ｎｉ）からなる群より選ばれた少なくと
も一種であることが好ましい。さらに、もう一方の主要
構成要素である黒鉛については、その黒鉛結晶のｃ軸方
向の面間隔ｄ002が３．５オングストローム以下の高結
晶性の黒鉛材料であることが好ましい。このような構成
を有する窒素化合物を活物質とした電極を用いることに
より上記課題は解決しうる。なお、上記式中のα値は活
物質中のＬｉの含有量を表し、充放電により変化する変
数である。Here, the value of β is suitably in the range of 0.1 ≦ β ≦ 0.8. The transition metal M is cobalt (C
o), iron (Fe), manganese (Mn), copper (Cu), and at least one selected from the group consisting of nickel (Ni). Further, with respect to graphite, which is the other main component, it is preferable that the graphite crystal be a highly crystalline graphite material having a surface spacing d 002 in the c-axis direction of 3.5 Å or less. The above problem can be solved by using an electrode using a nitrogen compound having such a structure as an active material. The α value in the above formula represents the content of Li in the active material, and is a variable that changes with charging and discharging.
【０００９】[0009]
【発明の実施の形態】本発明のリチウム二次電池は、Ｌ
ｉαＭβＮで表されるリチウム含有複合窒化物を電極の
活物質に用い、その電極が前記化合物と黒鉛とをその主
要構成要素として含んでいる。この構成の電極において
は、黒鉛は元来リチウムイオン電池の負極材料に用いら
れているように、それ自身Ｌｉの吸蔵・放出を行う活物
質となるが、さらに導電剤の役割も果たす。導電剤とし
ては、従来例のようにアセチレンブラックがその導電性
と集電能力の高さから広く用いられてきた。しかし、本
発明者らが検討した結果、高温ではこのリチウム含有複
合窒化物電極の作動電位においてアセチレンブラックの
活性が電解液を分解する原因となっていることが判明し
た。BEST MODE FOR CARRYING OUT THE INVENTION The lithium secondary battery of the present invention
A lithium-containing composite nitride represented by iαMβN is used as an active material of an electrode, and the electrode contains the compound and graphite as main components. In the electrode having such a configuration, graphite itself is an active material for occluding and releasing Li, as originally used for a negative electrode material of a lithium ion battery, but also plays a role of a conductive agent. As the conductive agent, acetylene black has been widely used because of its high conductivity and current collecting ability as in the conventional example. However, as a result of investigations by the present inventors, it has been found that at high temperatures, the activity of acetylene black causes the decomposition of the electrolytic solution at the operating potential of the lithium-containing composite nitride electrode.
【００１０】一方、黒鉛は、同じ炭素材料でも、負極活
物質としての実績もさることながら、高温でもこの窒素
化合物の作動電位で安定に働くことがわかっている。従
って、導電剤として黒鉛を用いることにより、上記分解
反応を回避することができる。さらに、黒鉛を用いた場
合、アセチレンブラックに比べて嵩が低いため、充填性
が向上することと、黒鉛そのものがこのリチウム含有複
合窒化物の作動電位で活物質として働くため容量にも寄
与するという利点がある。実際に黒鉛を導電剤として含
ませた電極を用いて高温、例えば６０℃の環境下で充放
電したところ、その充放電効率は少なくとも９９．９５
％以上を示し、サイクルに伴う容量劣化も極めて少なか
った。[0010] On the other hand, it has been found that even with the same carbon material, graphite works not only as a negative electrode active material but also stably at the operating potential of this nitrogen compound even at high temperatures. Therefore, the above decomposition reaction can be avoided by using graphite as the conductive agent. Furthermore, when graphite is used, its bulkiness is lower than that of acetylene black, so that the filling property is improved, and the graphite itself acts as an active material at the operating potential of this lithium-containing composite nitride, which also contributes to the capacity. There are advantages. When an electrode containing graphite as a conductive agent was actually charged and discharged at a high temperature, for example, at 60 ° C., the charging and discharging efficiency was at least 99.95.
% Or more, and the capacity deterioration accompanying the cycle was extremely small.
【００１１】元来ＬｉαＭβＮで表されるリチウム含有
複合窒化物は、Ｌｉ3ＮのＬｉの一部を他の金属元素Ｍ
で置換した形で合成される。従って、式中のαとβは基
本的にα＋β＝３の関係となる。元のＬｉ3Ｎは、固体
電解質ではあるが、電子伝導性はなく活物質とは成り得
なかったが、遷移金属を添加することにより電子伝導性
が付加された混合導電体となり、活物質として働くよう
になった。βが増加すると活物質の電子伝導性は向上す
る。本発明者らのこれまでの検討結果によると、活物質
としての機能を発揮する電子伝導性が得られるために
は、βは０．１以上は必要であることがわかった。さら
に、βが増加するにつれて電子伝導性は向上したが、β
が０．８を超えると急激に容量が低下した。この活物質
中の遷移金属Ｍは、充放電の際の移動種であるＬｉのサ
イトに置換するもので、過剰の置換はＬｉの移動障害を
招き活物質としての機能失わせることは明かである。す
なわち、β＝０．８がＬｉの移動障害を起こす臨界点で
あると考えられる。従って、ＬｉαＭβＮのβ値が０．
１≦β≦０．８の範囲にある活物質が有効である。The lithium-containing composite nitride originally represented by LiαMβN is obtained by converting a part of Li of Li 3 N to another metal element M
It is synthesized in the form substituted by Therefore, α and β in the equation basically have a relationship of α + β = 3. Although the original Li 3 N is a solid electrolyte, it did not have electronic conductivity and could not be an active material, but it became a mixed conductor with added electronic conductivity by adding a transition metal, and as an active material Started to work. As β increases, the electron conductivity of the active material improves. According to the results of the studies by the present inventors, it has been found that β must be 0.1 or more in order to obtain electron conductivity exhibiting a function as an active material. Furthermore, the electron conductivity improved as β increased, but β
Exceeds 0.8, the capacity rapidly decreased. The transition metal M in the active material substitutes for the site of Li, which is a mobile species at the time of charge and discharge, and it is clear that excessive replacement causes Li to hinder migration and lose its function as an active material. . That is, it is considered that β = 0.8 is a critical point at which Li migration hindrance occurs. Therefore, the β value of LiαMβN is 0.
Active materials in the range of 1 ≦ β ≦ 0.8 are effective.
【００１２】リチウム含有複合窒化物ＬｉαＭβＮとし
ては、Ｍは遷移金属に限らず多くの元素のものが存在す
る。しかし、電極活物質として用いた場合は、基本的
に、Ｌｉの吸蔵・放出による電荷移動のために化合物中
の元素の価数変化を伴う。よりスムーズに充放電反応を
進行させるためには、スムーズな価数変化が好ましい。
従って、遷移金属のように容易に価数変化するものが好
ましく、特に価数の変化幅の大きな元素を含むことがな
お好ましい。このような点でＣｏ、Ｆｅ、Ｍｎ、Ｎｉは
最適といえる。実際、上記元素を含む活物質において優
れた可逆性と高容量を示した。In the lithium-containing composite nitride LiαMβN, M is not limited to a transition metal but includes many elements. However, when used as an electrode active material, the valence of the element in the compound changes basically due to charge transfer due to insertion and extraction of Li. In order for the charge / discharge reaction to proceed more smoothly, a smooth valence change is preferable.
Therefore, it is preferable that the valence changes easily, such as a transition metal, and it is particularly preferable to include an element having a large valence change width. In such a point, Co, Fe, Mn, and Ni can be said to be optimal. In fact, the active material containing the above elements showed excellent reversibility and high capacity.
【００１３】本発明の電極に用いる黒鉛は、その結晶の
ｃ軸方向の面間隔ｄ002が３．５オングストローム以下
である高結晶性の黒鉛材料が好ましい。黒鉛の結晶性を
示すパラメーターとしてｃ軸方向の面間隔ｄ002の大き
さがよく用いられる。本発明における黒鉛の役割もこの
結晶性に大きく依存することがわかった。その一つは、
黒鉛の導電剤としての機能、すなわち電子伝導性であ
る。この電子伝導性は、結晶性が高いほど（ｄ002が小
さいほど）良好である。検討の結果、ｄ002が３．５オ
ングストローム以下であれば十分な導電剤となることが
わかった。次に、黒鉛の電解液の分解に対する反応性の
問題である。検討の結果、ｄ002が３．５オングストロ
ームを越える場合、上記従来例のＡＢを用いたときに見
られたような電解液の分解反応によるものと思える充放
電効率の低下が発生した。これは、ｄ002が３．５オン
グストロームを越える場合、低結晶性の炭素質が混入す
る確率が高くなり、この炭素材によって上記分解反応が
引き起こされるためだと考えられる。いくつかの黒鉛材
料を用いてその結晶性と充放電効率の関係を調べたとこ
ろ、ｄ002が３．５オングストローム以下である高結晶
性の黒鉛材料を用いることにより、この問題を回避しう
ることがわかった。The graphite used for the electrode of the present invention is preferably a highly crystalline graphite material having a crystal spacing d 002 of 3.5 angstroms or less in the c-axis direction. As a parameter indicating the crystallinity of graphite, the magnitude of the plane distance d 002 in the c-axis direction is often used. It has been found that the role of graphite in the present invention also greatly depends on this crystallinity. One of them is
It has the function of graphite as a conductive agent, ie, electronic conductivity. This electron conductivity is better as the crystallinity is higher ( d002 is smaller). As a result of the study, it was found that if d 002 is 3.5 Å or less, the conductive agent is sufficient. The second problem is the reactivity of graphite with respect to decomposition of the electrolytic solution. As a result of the study, when d 002 exceeds 3.5 angstroms, the charge / discharge efficiency, which seems to be due to the decomposition reaction of the electrolytic solution as seen when the above-mentioned conventional AB was used, was lowered. This is considered to be because when d 002 exceeds 3.5 angstroms, the probability of mixing low-crystalline carbonaceous material increases, and the decomposition reaction is caused by this carbon material. The relationship between the crystallinity and charge / discharge efficiency of several graphite materials was investigated. This problem can be avoided by using a highly crystalline graphite material with d 002 of 3.5 Å or less. I understood.
【００１４】以上のように、本発明のリチウム二次電池
においては、上記の条件のもとでリチウム含有複合窒化
物の作動電位においてその電極の機能を最大限に発揮さ
せることができる。なお、本発明では活物質をリチウム
含有複合窒化物と言及しているが、ここで導電剤として
用いる黒鉛もリチウムイオン電池の負極となるＬｉ吸蔵
体であり、厳密にはその作動電位の範囲内で両者とも活
物質として働く。黒鉛は窒素化合物より容量は小さい
が、作動電位が卑で、負極に用いると電池電圧は高くな
る。従って、負極に用いる場合、リチウム含有複合窒化
物と黒鉛の混合比率を変えることにより、作動電圧と容
量に関して設計上の制御も可能である。また、黒鉛を主
体にしたリチウムイオン電池用の負極にこの種のリチウ
ム含有複合窒化物を少量含む場合、この窒素化合物に含
まれるリチウムで黒鉛の容量ロス（１サイクル目のみ吸
蔵されたＬｉの一部が放出されない現象による不可逆容
量）を補填することも可能である。以上のように窒素化
合物と黒鉛の組み合わせにより多くの効用が現れる。As described above, in the lithium secondary battery of the present invention, the function of the electrode can be maximized at the operating potential of the lithium-containing composite nitride under the above conditions. In the present invention, the active material is referred to as a lithium-containing composite nitride, but the graphite used as a conductive agent is also a Li occluder serving as a negative electrode of a lithium ion battery, and strictly within the range of its operating potential. And both work as active materials. Graphite has a smaller capacity than nitrogen compounds, but has a lower operating potential, and when used as a negative electrode, battery voltage increases. Therefore, when used for the negative electrode, the design of the operating voltage and capacity can be controlled by changing the mixing ratio of the lithium-containing composite nitride and graphite. Further, when a negative electrode for a lithium ion battery mainly composed of graphite contains a small amount of this kind of lithium-containing composite nitride, the lithium contained in the nitrogen compound causes a capacity loss of the graphite (a loss of Li absorbed only in the first cycle). It is also possible to compensate for the irreversible capacity due to the phenomenon that no part is released. As described above, a combination of a nitrogen compound and graphite has many effects.
【００１５】[0015]
【実施例】以下、本発明を実施例を用いて詳細に説明す
る。 《実施例１》 １）リチウム含有複合窒化物の合成法：本発明のリチウ
ム含有複合窒化物は、基本的に出発物質として窒化リチ
ウム（Ｌｉ3Ｎ）の粉末と置換種の遷移金属の金属粉末
を所定量混合し、高純度の窒素雰囲気中で焼成すること
により得られる。ここで、具体例として、ＬｉαＭβＮ
におけるＭにＣｏ、β＝０．４の場合の合成法について
述べる。この活物質は、基本的にはＬｉ3Ｎをベースと
して、Ｌｉの一部をＣｏで置換したもので、Ｌｉ3-βＭ
βＮの形となる。すなわち、β＝０．４の場合、Ｌｉ
2.6Ｃｏ0.4Ｎの形で合成される。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. Example 1 1) Method for synthesizing lithium-containing composite nitride: The lithium-containing composite nitride of the present invention is basically composed of a powder of lithium nitride (Li 3 N) and a metal powder of a transition metal of a substituted species as starting materials. Are mixed in a predetermined amount and fired in a high-purity nitrogen atmosphere. Here, as a specific example, LiαMβN
The synthesis method in the case where Co is M and β = 0.4 will be described. This active material is basically as based on Li 3 N, obtained by substituting a part of Li with Co, Li 3- .beta.M
βN. That is, when β = 0.4, Li
It is synthesized in the form of 2.6 Co 0.4 N.
【００１６】まず、ＬｉとＣｏの原子比が２．６：０．
４となるようにＬｉ3Ｎ粉末とＣｏ粉末を混合し、十分
に混合した後にこれを坩堝に入れ、高純度（９９．９％
以上）の窒素雰囲気中において７００℃で８時間焼成し
た。なお、Ｌｉ3ＮとＣｏ粉末は市販の試薬を用いた。
特に、Ｃｏ粉末は粒径の細かいものほど混合状態が均一
で合成後の品質もよかった。ここでは、平均粒径５μｍ
のものを用いた。焼成後、窒素雰囲気中で焼結して塊と
なった材料を乳鉢を用いて十分に粉砕して活物質粉末と
した。ここでは典型的な例を示したが、Ｍとして他の遷
移金属種を用いた場合も同様の方法で合成が可能であっ
た。また、焼成から粉砕に至る工程は、この活物質が水
との反応性が高く、かつ酸化されやすい性質であるため
に、できる限り十分に乾燥した窒素雰囲気などの不活性
雰囲気中で実施されることが望ましい。First, the atomic ratio of Li to Co is 2.6: 0.
The Li 3 N powder and the Co powder were mixed so as to obtain a mixture No. 4, and after sufficient mixing, the mixture was put into a crucible, and then a high purity (99.9%
The above was fired at 700 ° C. for 8 hours in a nitrogen atmosphere. Note that commercially available reagents were used for the Li 3 N and Co powders.
In particular, the smaller the particle size of the Co powder, the more uniform the mixed state and the better the quality after the synthesis. Here, the average particle size is 5 μm
Was used. After sintering, the material obtained by sintering in a nitrogen atmosphere was sufficiently pulverized using a mortar to obtain an active material powder. Here, a typical example is shown, but when another transition metal species is used as M, synthesis was possible by the same method. In addition, the steps from baking to pulverization are performed in an inert atmosphere such as a nitrogen atmosphere that is as dry as possible because the active material has high reactivity with water and is easily oxidized. It is desirable.
【００１７】２）試験電極の作製法：上述の手法で作製
した活物質粉末１００重量部に対して導電剤としての黒
鉛粉末を２５重量部、結着剤としてのテフロン樹脂粉末
を５重量部加え、十分に混練した後にローラーで圧延し
てフィルム状に加工した。このフィルム状の合剤を定形
に裁断、または打ち抜いて試験電極として用いた。2) Preparation of test electrode: 25 parts by weight of graphite powder as a conductive agent and 5 parts by weight of Teflon resin powder as a binder are added to 100 parts by weight of the active material powder prepared by the above-mentioned method. After sufficiently kneading, the mixture was rolled with a roller to form a film. This film-shaped mixture was cut or punched into a fixed form and used as a test electrode.
【００１８】３）試験電池の製造方法：ここでは、直径
２０ｍｍ、厚み１．６ｍｍのコイン形の電池を用いた。
図１はこのコイン形電池の構造を示す。１は電池ケース
を示す。ケース１の内面にステンレス鋼製のエキスパン
ドメタルからなる集電体２が溶接してあり、この上に直
径１５ｍｍの円盤状に打ち抜いた試験電極３が圧着され
ている。試験電極３上に電解液を注入した後に、ポリプ
ロピレン製のセパレータ４とともに、内面に対極となる
円盤状の金属Ｌｉ電極５を圧着した封口板６をガスケッ
ト７を介して被せ、ケース端をかしめて封口し完成電池
とした。なお、電解液には、炭酸エチレンと炭酸ジエチ
ルの混合溶媒に、電解質として１モルの六フッ化リン酸
リチウム（ＬｉＰＦ6）を溶解したものを用いた。3) Manufacturing method of test battery: Here, a coin-shaped battery having a diameter of 20 mm and a thickness of 1.6 mm was used.
FIG. 1 shows the structure of this coin-shaped battery. Reference numeral 1 denotes a battery case. A current collector 2 made of an expanded metal made of stainless steel is welded to the inner surface of the case 1, and a test electrode 3 punched into a disk having a diameter of 15 mm is crimped thereon. After injecting the electrolytic solution onto the test electrode 3, a sealing plate 6 in which a disc-shaped metal Li electrode 5 serving as a counter electrode is crimped on the inner surface together with a polypropylene separator 4 via a gasket 7 and a case end is swaged. The sealed battery was completed. The electrolyte used was a solution obtained by dissolving 1 mol of lithium hexafluorophosphate (LiPF 6 ) as an electrolyte in a mixed solvent of ethylene carbonate and diethyl carbonate.
【００１９】４）電池の試験方法：上述のコイン形電池
を、０．５ｍＡ／ｃｍ2の定電流で、リチウム含有複合
窒化物の作動電位を考慮して上限カット電圧を１．５
Ｖ、下限カット電圧を０．１Ｖに設定した充放電サイク
ル試験を行った。なお、この電池の場合、予想される試
験電極の容量に対して対極の金属Ｌｉを過剰に充填した
設計（容量は十数倍）にしており、基本的に充放電特性
は試験電極に依存する。4) Battery test method: The above-mentioned coin-shaped battery was tested at a constant current of 0.5 mA / cm 2 at an upper limit cut voltage of 1.5 in consideration of the operating potential of the lithium-containing composite nitride.
V and a charge / discharge cycle test in which the lower limit cut voltage was set to 0.1 V was performed. In this battery, the design is such that the counter electrode metal Li is excessively filled with respect to the expected capacity of the test electrode (the capacity is more than ten times), and the charge / discharge characteristics basically depend on the test electrode. .
【００２０】先の処方で合成したＬｉ2.6Ｃｏ0.4Ｎを活
物質とし、導電剤に人造黒鉛（ロンザ社製の品番ＫＳ
６）を用いて極板を作製し、電池試験を行った。ここに
用いた人造黒鉛は、ｄ002＝３．３８オングストローム
の高結晶性の黒鉛である。図２に上記コイン形電池の充
電電圧および放電電圧の変化を示す。試験極を正極用の
電極と考えた場合は、Ｌｉの放出による貴な方向への変
化が充電（充電終止電圧＝１．５Ｖ）、Ｌｉの吸蔵によ
る卑な方向への変化が放電（放電終止電圧＝０．１Ｖ）
となり、負極用の電極と考えた場合はその逆となる。な
お、これは２０℃の環境下での充放電結果であり、活物
質単位重量あたりの容量を横軸に、電圧を縦軸にプロッ
トしたものである。この電池は、充電容量も放電容量も
ほぼ８３０ｍＡｈ／ｇ を示し、充放電効率（放電容量
／充電容量×１００％）は１００％であった。Li 2.6 Co 0.4 N synthesized according to the above formulation is used as an active material, and artificial graphite (product number KS manufactured by Lonza) is used as a conductive agent.
An electrode plate was prepared using 6), and a battery test was performed. The artificial graphite used here is highly crystalline graphite with d 002 = 3.38 Å. FIG. 2 shows changes in the charging voltage and the discharging voltage of the coin battery. When the test electrode is considered to be a positive electrode, a change in a noble direction due to the release of Li is charging (charge termination voltage = 1.5 V), and a change in a less noisy direction due to occlusion of Li is discharge (discharge termination). (Voltage = 0.1V)
When the electrode is considered as a negative electrode, the opposite is true. Note that this is a result of charging and discharging in an environment of 20 ° C., in which the capacity per unit weight of the active material is plotted on the horizontal axis, and the voltage is plotted on the vertical axis. This battery exhibited a charge capacity and a discharge capacity of about 830 mAh / g, and a charge / discharge efficiency (discharge capacity / charge capacity × 100%) of 100%.
【００２１】図３は、各環境温度におけるこの電池のサ
イクルに伴う放電容量の変化をプロットしたものであ
る。試験は、２０℃、４５℃、６０℃、および８０℃の
環境温度でそれぞれ行った。この電池は、８０℃でわず
かなサイクル劣化傾向がみられるものの、その他の環境
温度でははほとんど容量劣化なくサイクルが進行した。
充放電効率に関しては、５０サイクルまでの平均値を算
出した。８０℃で試験した場合に９９．５％を示した以
外は、９９．９５％以上の好結果を示した。FIG. 3 is a graph plotting the change in discharge capacity with the cycle of this battery at each environmental temperature. The tests were performed at ambient temperatures of 20 ° C, 45 ° C, 60 ° C, and 80 ° C, respectively. Although this battery showed a slight tendency to deteriorate at 80 ° C., the cycle proceeded with little capacity deterioration at other environmental temperatures.
Regarding the charge and discharge efficiency, an average value up to 50 cycles was calculated. Except that it showed 99.5% when tested at 80 ° C., it showed good results of 99.95% or more.
【００２２】《比較例１》導電剤として、黒鉛の代わり
に従来のアセチレンブラックを用いた他は、実施例１と
同様にして極板を作製し、電池試験を行った。図４は、
各環境温度におけるこの電池のサイクルに伴う放電容量
の変化をプロットしたものである。試験は、上記と同様
に２０℃、４５℃、６０℃、８０℃の環境温度でそれぞ
れ行った。この電池は、２０℃では上記実施例の場合と
同様にほとんど容量劣化なくサイクルが進行した。とこ
ろが、４５℃以上の環境温度では著しいサイクル劣化が
みられた。表１に、比較のため、上記黒鉛を導電剤に用
いた場合の結果も含めて各試験温度におけるこの電池の
充放電効率の結果を示す。表１より、アセチレンブラッ
クを用いた場合、明らかに充放電効率が著しく低下する
ことがわかる。Comparative Example 1 An electrode plate was prepared in the same manner as in Example 1 except that conventional acetylene black was used instead of graphite as a conductive agent, and a battery test was performed. FIG.
7 is a graph in which a change in discharge capacity according to a cycle of the battery at each environmental temperature is plotted. The test was performed at ambient temperature of 20 ° C., 45 ° C., 60 ° C., and 80 ° C. as described above. At 20 ° C., the cycle proceeded at 20 ° C. with almost no capacity deterioration as in the case of the above embodiment. However, remarkable cycle deterioration was observed at an environmental temperature of 45 ° C. or higher. Table 1 shows, for comparison, the results of the charging and discharging efficiency of this battery at each test temperature, including the results when the above graphite was used as the conductive agent. Table 1 shows that when acetylene black was used, the charging / discharging efficiency was significantly reduced.
【００２３】[0023]
【表１】 [Table 1]
【００２４】《実施例２》充放電効率の差は、電解液に
対する分解反応の差によるもので、これは黒鉛とアセチ
レンブラックの結晶性の違いによって起こると推定され
る。黒鉛などの結晶性を示すパラメータにｃ軸方向の面
間隔ｄ002（最も結晶性の高い黒鉛単結晶の場合、理論
値はｄ002＝３．３５４オングストロームであり、結晶
性が下がるにつれてこの値が大きくなる）がよく用いら
れる。本実施例では、このｄ002の値と充放電効率の関
係を調べた。市販されている炭素材料を数多く入手し、
これらの素材のｄ002値をＸ線回折法で測定するととも
に電池を作製して充放電効率を求めた。電極、および同
電極を用いた試験電池の作製方法、ならびに電池の試験
方法は実施例１と同様である。なお、試験した炭素材料
は、日本黒鉛製、ロンザ製など数社の製品から任意に選
び出したもので、多くはピッチまたはコークスの焼成体
である。Example 2 The difference in charge / discharge efficiency is due to the difference in decomposition reaction with the electrolytic solution, which is presumed to be caused by the difference in crystallinity between graphite and acetylene black. The parameter indicating the crystallinity of graphite or the like is a plane spacing d 002 in the c-axis direction (in the case of a graphite single crystal having the highest crystallinity, the theoretical value is d 002 = 3.354 angstroms. Larger) is often used. In the present embodiment, the relationship between the value of d 002 and the charge / discharge efficiency was examined. Obtain many commercially available carbon materials,
The d002 values of these materials were measured by X-ray diffraction, and batteries were prepared to determine the charge / discharge efficiency. An electrode, a method for manufacturing a test battery using the electrode, and a test method for the battery are the same as those in Example 1. The carbon material tested was arbitrarily selected from products of several companies, such as those manufactured by Nippon Graphite and Lonza, and was mostly a fired body of pitch or coke.
【００２５】図５は炭素材料のｄ002値と充放電効率と
の関係を示す。２０℃の環境下では、いずれも９９．５
％以上の高効率を示した。しかし、環境温度が上昇する
につれて、特に結晶性の低い炭素材料ほど充放電効率の
低下が著しかった。実用電池の場合、８０℃という環境
温度でも性能を保証する必要があるので、図５からも明
らかなように、ｄ002値は少なくとも３．５オングスト
ローム以下であることが好ましい。一般に、黒鉛結晶の
ａ軸方向の厚みであるＬａやｃ軸方向の厚みであるＬ
ｃ、またラマンスペクトルのピーク強度比などもその結
晶性を表すパラメータとして用いられる。しかし、図５
をみても明らかなように、任意の炭素材料を用いたにも
関わらずｄ002値に対する相関性は明確で、本発明に係
る炭素材料に関してはｄ002値で評価できる。FIG. 5 shows the relationship between the d 002 value of the carbon material and the charge / discharge efficiency. Under an environment of 20 ° C., each is 99.5
%. However, as the environmental temperature increases, the charge / discharge efficiency of the carbon material having a lower crystallinity decreases more remarkably. In the case of a practical battery, it is necessary to guarantee the performance even at an environmental temperature of 80 ° C., and therefore it is preferable that the d 002 value is at least 3.5 angstroms or less, as is clear from FIG. Generally, La, which is the thickness of the graphite crystal in the a-axis direction, and L, which is the thickness of the graphite crystal in the c-axis direction.
c, the peak intensity ratio of the Raman spectrum, and the like are also used as parameters representing the crystallinity. However, FIG.
As is clear from the above, the correlation with the d 002 value is clear despite the use of any carbon material, and the carbon material according to the present invention can be evaluated with the d 002 value.
【００２６】以上の実施例では、リチウム含有複合窒化
物としてＬｉ2.6Ｃｏ0.4Ｎを用いたが、ＬｉαＭβＮに
おけるＭにＦｅ、Ｍｎ、Ｃｕ、またはニッケルＮｉを用
いた活物質、またその添加量のβ値が０．１≦β≦０．
８の範囲にある種々の組成比のリチウム含有複合窒化物
についても上記実施例と同様の検討を加えた。その結
果、上記実施例とほぼ同様の結果が得られた。また、電
解液の分解反応に起因する特性差ということもあり、電
解液の種類による依存性についても調べた。その結果、
電解質に六フッ化リン酸リチウム（ＬｉＰＦ6）の代わ
りに過塩素酸リチウム（ＬｉＣｌＯ4)、硼フッ化リチウ
ム（ＬｉＢＦ4) など他の塩を用いた場合もその効果は
変わらなかった。また、電解液の溶媒として、炭酸エチ
レン、炭酸プロピレン、炭酸ジメチル、炭酸ジエチル等
の炭酸エステルを各種組み合わせた混合溶媒や、これに
さらに酢酸メチル、プロピオン酸メチル等の鎖状エステ
ルを混合したものについても検討をしたが、その効果の
傾向は上記実施例とほぼ同様であった。以上のように、
リチウム含有複合窒化物を電極に用いる場合は、その作
動電位の関係も含めて、結晶性の高い黒鉛が導電剤とし
て適しているといえる。In the above embodiment, Li 2.6 Co 0.4 N was used as the lithium-containing composite nitride. However, an active material using Li, Mn, Cu, or nickel Ni as M in LiαMβN, and the added amount β When the value is 0.1 ≦ β ≦ 0.
The same study as in the above example was made for lithium-containing composite nitrides having various composition ratios within the range of 8. As a result, almost the same results as in the above example were obtained. In addition, because of the characteristic difference caused by the decomposition reaction of the electrolytic solution, the dependence on the type of the electrolytic solution was also examined. as a result,
When other salts such as lithium perchlorate (LiClO 4 ) and lithium borofluoride (LiBF 4 ) were used instead of lithium hexafluorophosphate (LiPF 6 ) for the electrolyte, the effect was not changed. In addition, as a solvent for the electrolytic solution, a mixed solvent in which various types of carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, and diethyl carbonate are combined, and those in which a chain ester such as methyl acetate and methyl propionate are further mixed. However, the tendency of the effect was almost the same as that of the above example. As mentioned above,
In the case where a lithium-containing composite nitride is used for the electrode, it can be said that graphite having high crystallinity is suitable as the conductive agent, including the relation of the operating potential.
【００２７】[0027]
【発明の効果】以上のように本発明によれば、リチウム
含有複合窒化物を特に負極用の活物質として用いる場合
に、幅広い環境温度で高い信頼性のリチウム二次電池を
得ることができる。As described above, according to the present invention, a highly reliable lithium secondary battery can be obtained over a wide range of environmental temperatures, particularly when a lithium-containing composite nitride is used as an active material for a negative electrode.
【図１】本発明の一実施例に用いた試験電池の縦断面図
である。FIG. 1 is a longitudinal sectional view of a test battery used in one embodiment of the present invention.
【図２】本発明の実施例に用いた電極の充放電挙動を示
す図である。FIG. 2 is a diagram showing the charge and discharge behavior of an electrode used in an example of the present invention.
【図３】本発明の実施例に用いた電極のサイクル特性図
である。FIG. 3 is a cycle characteristic diagram of an electrode used in an example of the present invention.
【図４】比較例の電極のサイクル特性図である。FIG. 4 is a cycle characteristic diagram of an electrode of a comparative example.
【図５】導電剤炭素材料の結晶性と充放電効率との関係
を示す図である。FIG. 5 is a diagram showing the relationship between the crystallinity of a conductive carbon material and charge and discharge efficiency.
１ ケース ２ 集電体 ３ 試験電極 ４ セパレータ ５ 金属リチウム ６ 封口板 ７ ガスケット DESCRIPTION OF SYMBOLS 1 Case 2 Current collector 3 Test electrode 4 Separator 5 Metal lithium 6 Sealing plate 7 Gasket
───────────────────────────────────────────────────── フロントページの続き (72)発明者 堤 修司 大阪府守口市松下町１番１号 松下電池工 業株式会社内 (72)発明者 近藤 繁雄 大阪府守口市松下町１番１号 松下電池工 業株式会社内 (72)発明者 山木 準一 東京都新宿区西新宿三丁目19番２号 日本 電信電話株式会社内 (72)発明者 櫻井 庸司 東京都新宿区西新宿三丁目19番２号 日本 電信電話株式会社内 (72)発明者 正代 尊久 東京都新宿区西新宿三丁目19番２号 日本 電信電話株式会社内 (72)発明者 斉藤 景一 東京都新宿区西新宿三丁目19番２号 日本 電信電話株式会社内 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shuji Tsutsumi 1-1, Matsushita-cho, Moriguchi-shi, Osaka Matsushita Battery Industry Co., Ltd. (72) Inventor Shigeo Kondo 1-1-1, Matsushita-cho, Moriguchi-shi, Osaka Matsushita Battery Within Industrial Co., Ltd. (72) Inventor Junichi Yamaki 3-192-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Yoji Sakurai 3-192-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo Within Nippon Telegraph and Telephone Corporation (72) Takahisa Masayo, Inventor 3- 19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo Within Nippon Telegraph and Telephone Corporation (72) Keiichi Saito 3-19, Nishi-Shinjuku, Shinjuku-ku, Tokyo No. 2 Nippon Telegraph and Telephone Corporation
Claims (4)
も一方の電極が、式ＬｉαＭβＮ（Ｍは遷移金属であ
り、αは窒素１原子当たりのリチウムの原子数比、βは
窒素１原子当たりのＭの原子数比である。）で表される
リチウム含有複合窒化物を電極活物質として含み、かつ
黒鉛を含むことを特徴とするリチウム二次電池。1. An electrode comprising a pair of electrodes and an electrolyte, wherein at least one electrode has a formula LiαMβN (M is a transition metal, α is a ratio of lithium atoms per nitrogen atom, and β is a The lithium secondary battery contains a lithium-containing composite nitride represented by the following formula (1) as an electrode active material and graphite.
のリチウム二次電池。2. The lithium secondary battery according to claim 1, wherein 0.1 ≦ β ≦ 0.8.
ｉからなる群より選ばれた少なくとも一種である請求項
１記載のリチウム二次電池。3. M is Co, Fe, Mn, Cu, and N
2. The lithium secondary battery according to claim 1, wherein the lithium secondary battery is at least one selected from the group consisting of i.
面間隔ｄ002が３．５オングストローム以下の高結晶性
の黒鉛材料である請求項１記載のリチウム二次電池。4. The lithium secondary battery according to claim 1, wherein the graphite is a highly crystalline graphite material having a d-spacing d 002 of 3.5 angstrom or less in a c-axis direction of the graphite crystal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9113001A JPH10302765A (en) | 1997-04-30 | 1997-04-30 | Lithium secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9113001A JPH10302765A (en) | 1997-04-30 | 1997-04-30 | Lithium secondary battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH10302765A true JPH10302765A (en) | 1998-11-13 |
Family
ID=14600963
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9113001A Pending JPH10302765A (en) | 1997-04-30 | 1997-04-30 | Lithium secondary battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH10302765A (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000033399A1 (en) * | 1998-11-30 | 2000-06-08 | Matsushita Electric Industrial Co., Ltd. | Non-aqueous electrolyte secondary cell |
| JP2009506483A (en) * | 2005-08-03 | 2009-02-12 | カリフォルニア インスティテュート オブ テクノロジー | Electrochemical thermodynamic measurement system |
| JP2010102841A (en) * | 2008-10-21 | 2010-05-06 | Nec Tokin Corp | Nonaqueous electrolyte lithium-ion secondary battery |
| US8446127B2 (en) | 2005-08-03 | 2013-05-21 | California Institute Of Technology | Methods for thermodynamic evaluation of battery state of health |
| US9065292B2 (en) | 2010-08-23 | 2015-06-23 | California Institute Of Technology | Methods and systems for charging electrochemical cells |
| JP2015135770A (en) * | 2014-01-17 | 2015-07-27 | 株式会社東芝 | Negative electrode and nonaqueous electrolyte battery |
| US9599584B2 (en) | 2012-04-27 | 2017-03-21 | California Institute Of Technology | Imbedded chip for battery applications |
| JP2020017391A (en) * | 2018-07-25 | 2020-01-30 | パナソニックＩｐマネジメント株式会社 | Nonaqueous electrolyte battery |
| US10556510B2 (en) | 2012-04-27 | 2020-02-11 | California Institute Of Technology | Accurate assessment of the state of charge of electrochemical cells |
-
1997
- 1997-04-30 JP JP9113001A patent/JPH10302765A/en active Pending
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000033399A1 (en) * | 1998-11-30 | 2000-06-08 | Matsushita Electric Industrial Co., Ltd. | Non-aqueous electrolyte secondary cell |
| US6410188B1 (en) | 1998-11-30 | 2002-06-25 | Matsushita Electric Industrial Co., Ltd. | Non-aqueous electrolyte secondary cell |
| JP2009506483A (en) * | 2005-08-03 | 2009-02-12 | カリフォルニア インスティテュート オブ テクノロジー | Electrochemical thermodynamic measurement system |
| JP2013069695A (en) * | 2005-08-03 | 2013-04-18 | California Inst Of Technology | Electrochemical thermodynamic measurement system |
| US8446127B2 (en) | 2005-08-03 | 2013-05-21 | California Institute Of Technology | Methods for thermodynamic evaluation of battery state of health |
| US8901892B2 (en) | 2005-08-03 | 2014-12-02 | California Institute Of Technology | Methods and systems for thermodynamic evaluation of battery state of health |
| JP2010102841A (en) * | 2008-10-21 | 2010-05-06 | Nec Tokin Corp | Nonaqueous electrolyte lithium-ion secondary battery |
| US9065292B2 (en) | 2010-08-23 | 2015-06-23 | California Institute Of Technology | Methods and systems for charging electrochemical cells |
| US9599584B2 (en) | 2012-04-27 | 2017-03-21 | California Institute Of Technology | Imbedded chip for battery applications |
| US10556510B2 (en) | 2012-04-27 | 2020-02-11 | California Institute Of Technology | Accurate assessment of the state of charge of electrochemical cells |
| JP2015135770A (en) * | 2014-01-17 | 2015-07-27 | 株式会社東芝 | Negative electrode and nonaqueous electrolyte battery |
| JP2020017391A (en) * | 2018-07-25 | 2020-01-30 | パナソニックＩｐマネジメント株式会社 | Nonaqueous electrolyte battery |
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