JP2004152619A - Nonaqueous electrolyte cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain swelling of an exterior material when it is stored under a high temperature. <P>SOLUTION: The nonaqueous electrolyte cell is equipped with a positive electrode 5 having a positive electrode mixture layer 10, a negative electrode 6 having a negative electrode combined agent layer 13, a solid electrolyte 7, a gas absorbing board 3 having one or more lithium-containing oxides expressed in formulas; Li<SB>x</SB>Si<SB>y</SB>O<SB>z</SB>( In the formula, x, y and z are greater than 0) and Li<SB>x</SB>Zr<SB>y</SB>O<SB>z</SB>( In the formula, x, y and z are greater than 0), and an outer package material 4 sealing the positive electrode 5, the negative electrode 6, the solid electrolyte 7 and the gas absorbing board 3 together. Since the gas absorbing board 3 absorbs generated gas inside by high temperature preservation, and prevents gas from accumulating inside, the swelling of the outer package material by the accumulated gas inside can be prevented. <P>COPYRIGHT: (C)2004,JPO

Description

【００６２】
なお、高温保存による膨れ量は次のようにして測定した。各サンプルに対し、充電電流０．２Ｃで４．２Ｖ迄の定電流定電圧で充電した後に、充電電流０．５Ｃで４．３５迄の定電流定電圧で充電する過充電を行った。次に、過充電された各サンプルの厚みを測定した後に、１００℃雰囲気下で１００時間保存した。次に、高温保存後、室温まで冷却した各サンプルの厚みを再び測定した。このようにして、高温保存による膨れ量を測定した。そして、各サンプルにおける高温保存による膨れ量は、高温保存前後の電池厚みの差である。
【００６３】
表１に示す評価結果から、外装材に電池素子と一緒にガス吸収剤が封入されたサンプル１〜サンプル３では、外装材にガス吸収剤を封入させなかったサンプル４に比べ、高温保存による膨れ量が大幅に小さくなっていることがわかる。
【００６４】
サンプル４では、電池内部にガス吸収剤が無く電池内に発生したガスが吸収されないことから、過充電や高温保存によりゲル状電解質等が分解して生じた炭酸ガスが電池内部に貯留し、フィルム状の外装材を風船のように膨らませてしまい電池厚みが大幅に厚くなる。
【００６５】
これに対し、サンプル１〜サンプル３では、電池内部に電池素子と一緒にガス吸収剤が封入されており、ガス吸収剤が電池内で発生したガスを吸収することから、過充電や高温保存によりゲル状電解質等が分解して生じた炭酸ガスが電池内部に貯留することを防ぎ、過充電や高温保存により電池厚みが厚くなることを抑制する。したがって、サンプル１〜サンプル３では、サンプル４に比べて高温保存による膨れ量が大幅に小さくなる。
【００６６】
以上のことから、電池を製造する際に、電池素子と一緒にガス吸収剤を電池内部に封入させることは、高温保存による膨れ量が抑制されている優れた電池を製造する上で大変有効であることがわかる。
【００６７】
次に、上述したサンプル１〜サンプル３とは、ガス吸収剤の含有される場所を正極合剤層に変えて製造したサンプル５〜サンプル９について説明する。
【００６８】
〈サンプル５〉
サンプル５では、正極を作製する際に、ＬｉＣｏＯ_２を９０．９重量部と、ガス吸収剤としてＬｉ_４ＳｉＯ_４を０．１重量部と、導電材としてグラファイトを６重量部と、結着剤としてＰＶｄＦを３重量部と、溶剤としてＮＭＰとを加えて分散して正極合剤塗液を調製し、この正極合剤塗液を用いること以外は、サンプル１と同様にして正極合剤層にガス吸収剤が０．１重量％含有された正極を作製した。そして、この正極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【００６９】
〈サンプル６〉
サンプル６では、正極を作製する際に、ＬｉＣｏＯ_２を８６重量部と、ガス吸収剤としてＬｉ_４ＳｉＯ_４を５重量部と、導電材としてグラファイトを６重量部と、結着剤としてＰＶｄＦを３重量部と、溶剤としてＮＭＰとを加えて分散して正極合剤塗液を調製し、この正極合剤塗液を用いること以外は、サンプル１と同様にして正極合剤層にガス吸収剤が５重量％含有された正極を作製した。そして、この正極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【００７０】
〈サンプル７〉
サンプル７では、正極を作製する際に、ＬｉＣｏＯ_２を８３重量部と、ガス吸収剤としてＬｉ_４ＳｉＯ_４を８重量部と、導電材としてグラファイトを６重量部と、結着剤としてＰＶｄＦを３重量部と、溶剤としてＮＭＰとを加えて分散して正極合剤塗液を調製し、この正極合剤塗液を用いること以外は、サンプル１と同様にして正極合剤層にガス吸収剤が８重量％含有された正極を作製した。そして、この正極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【００７１】
〈サンプル８〉
サンプル８では、正極を作製する際に、ＬｉＣｏＯ_２を９０．９５重量部と、ガス吸収剤としてＬｉ_４ＳｉＯ_４を０．０５重量部と、導電材としてグラファイトを６重量部と、結着剤としてＰＶｄＦを３重量部と、溶剤としてＮＭＰとを加えて分散して正極合剤塗液を調製し、この正極合剤塗液を用いること以外は、サンプル１と同様にして正極合剤層にガス吸収剤が０．０５重量％含有された正極を作製した。そして、この正極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【００７２】
〈サンプル９〉
サンプル９では、正極を作製する際に、ＬｉＣｏＯ_２を８２重量部と、ガス吸収剤としてＬｉ_４ＳｉＯ_４を９重量部と、導電材としてグラファイトを６重量部と、結着剤としてＰＶｄＦを３重量部と、溶剤としてＮＭＰとを加えて分散して正極合剤塗液を調製し、この正極合剤塗液を用いること以外は、サンプル１と同様にして正極合剤層にガス吸収剤が９重量％含有された正極を作製した。そして、この正極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【００７３】
そして、以上のように製造したサンプル５〜サンプル９の電池について、高温保存による膨れ量、放電容量、高温保存後の放電容量維持率を測定した。
【００７４】
以下、各サンプルにおける、高温保存による膨れ量、放電容量、高温保存後の放電容量維持率の評価結果を表２に示す。
【００７５】
【表２】

【００７６】
なお、各サンプルおいて、高温保存による膨れ量は、上述したサンプル１〜サンプル４と同様にして測定した。また、放電容量及び高温保存後の放電容量維持率は、次のようにして測地した。各サンプルに対し、充電電流を１Ａ、充電電圧を４．２Ｖ、充電時間を３時間する定電流定電圧で充電し、放電電流を０．２Ａ、放電終止電圧を２．５Ｖとする定電流で放電する充放電条件で充放電を行い、初回放電容量を測定した。次に、初回充電と同様の条件で充電した各サンプルを、５５℃雰囲気下で５００時間保存し、保存後に初回放電と同様の条件で放電した。次に、高温保存後に放電した各サンプルに対し、初回の充放電条件で充放電を行い、高温保存後の放電容量を測定した。そして、放電容量は、以上のようにして測定した初回放電容量であり、高温保存後の放電容量維持率は、初回放電容量に対する高温保存後の放電容量維持率の比率である。
【００７７】
表２に示す評価結果から、正極合剤層にガス吸収剤を０．１重量％以上、８重量％以下の範囲で含有させたサンプル５〜サンプル７では、正極合剤層にガス吸収剤を０．０５重量％含有させたサンプル８に比べ、高温保存による膨れ量が小さく、高温保存後の放電容量維持率が大きくなっていることがわかる。
【００７８】
サンプル８では、正極合剤層に含有されるガス吸収剤が少なすぎることから、高温保存により電池内部に発生した炭酸ガス等を適切に吸収させることが困難であり、外装材が風船のように膨れて電池厚みが厚くなる。また、サンプル８では、高温保存により正極合剤層及び負極合剤層の内部にも炭酸ガス等が発生し、この合剤層内のガスが集電体より合剤層を剥がしてしまうことから、高温保存後の電池容量が小さくなる。
【００７９】
また、表２に示す評価結果から、サンプル５〜サンプル７では、正極合剤層にガス吸収剤を９重量％含有させたサンプル９に比べ、電池容量が大きくなっていることがわかる。
【００８０】
サンプル９では、正極合剤層に含有されるガス吸収剤が多すぎて、正極合剤層に含有される正極活物質の割合を少なくすることから、電池容量が小さくなる。
【００８１】
サンプル８及びサンプル９に対し、サンプル５〜サンプル７では、正極合剤層に含有されるガス吸収剤が０．１重量％以上、８重量％以下の範囲であり、適切な量含有されていることから、電池内部に発生した炭酸ガス等を吸収して電池内にガスが貯留することを防ぎ、正極活物質も適宜な量含有されている。したがって、サンプル５〜サンプル７では、放電容量の低下と高温保存による電池特性の低下とが抑制される。
【００８２】
次に、上述したサンプル１〜サンプル３とは、ガス吸収剤の含有される場所を負極合剤層に変えて製造したサンプル１０〜サンプル１４について説明する。
【００８３】
〈サンプル１０〉
サンプル１０では、負極を作製する際に、黒鉛粉末を８９．８重量部と、ガス吸収剤としてＬｉ_４ＳｉＯ_４を０．２重量部と、結着剤としてＰＶｄＦを１０重量部と、溶剤としてＮＭＰとを加えて分散して負極合剤塗液を調製し、この負極合剤塗液を用いること以外は、サンプル１と同様にして負極合剤層にガス吸収剤が０．２重量％含有された負極を作製した。そして、この負極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【００８４】
〈サンプル１１〉
サンプル１１では、負極を作製する際に、黒鉛粉末を８４重量部と、ガス吸収剤としてＬｉ_４ＳｉＯ_４を６重量部と、結着剤としてＰＶｄＦを１０重量部と、溶剤としてＮＭＰとを加えて分散して負極合剤塗液を調製し、この負極合剤塗液を用いること以外は、サンプル１と同様にして負極合剤層にガス吸収剤が６重量％含有された負極を作製した。そして、この負極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【００８５】
〈サンプル１２〉
サンプル１２では、負極を作製する際に、黒鉛粉末を８０重量部と、ガス吸収剤としてＬｉ_４ＳｉＯ_４を１０重量部と、結着剤としてＰＶｄＦを１０重量部と、溶剤としてＮＭＰとを加えて分散して負極合剤塗液を調製し、この負極合剤塗液を用いること以外は、サンプル１と同様にして負極合剤層にガス吸収剤が１０重量％含有された負極を作製した。そして、この負極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【００８６】
〈サンプル１３〉
サンプル１３では、負極を作製する際に、黒鉛粉末を８９．９重量部と、ガス吸収剤としてＬｉ_４ＳｉＯ_４を０．１重量部と、結着剤としてＰＶｄＦを１０重量部と、溶剤としてＮＭＰとを加えて分散して負極合剤塗液を調製し、この負極合剤塗液を用いること以外は、サンプル１と同様にして負極合剤層にガス吸収剤が０．１重量％含有された負極を作製した。そして、この負極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【００８７】
〈サンプル１４〉
サンプル１４では、負極を作製する際に、黒鉛粉末を７９重量部と、ガス吸収剤としてＬｉ_４ＳｉＯ_４を１１重量部と、結着剤としてＰＶｄＦを１０重量部と、溶剤としてＮＭＰとを加えて分散して負極合剤塗液を調製し、この負極合剤塗液を用いること以外は、サンプル１と同様にして負極合剤層にガス吸収剤が１１重量％含有された負極を作製した。そして、この負極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【００８８】
そして、以上のように製造したサンプル１０〜サンプル１４の電池について、高温保存による膨れ量、放電容量、高温保存後の放電容量維持率を測定した。
【００８９】
以下、各サンプルにおける、高温保存による膨れ量、放電容量、高温保存後の放電容量維持率の評価結果を表３に示す。
【００９０】
【表３】

【００９１】
なお、各サンプルおいて、高温保存による膨れ量は、上述したサンプル１〜サンプル４と同様にして測定した。また、放電容量及び高温保存後の放電容量維持率は、上述したサンプル５〜サンプル９と同様にして測定した。
【００９２】
表３に示す評価結果から、負極合剤層にガス吸収剤を０．２重量％以上、１０重量％以下の範囲で含有させたサンプル１０〜サンプル１２では、負極合剤層にガス吸収剤を０．１重量％含有させたサンプル１３に比べ、高温保存による膨れ量が小さく、高温保存後の放電容量維持率が大きくなっていることがわかる。
【００９３】
サンプル１３では、負極合剤層に含有されるガス吸収剤が少なすぎることから、サンプル８と同様に、高温保存により電池内部に発生した炭酸ガス等を適切に吸収させることが困難であり、外装材が風船のように膨れて電池厚みが厚くなる。また、サンプル１３では、高温保存により正極合剤層及び負極合剤層の内部にも炭酸ガス等が発生し、この合剤層内のガスが集電体より合剤層を剥がしてしまうことから、高温保存後の電池容量が小さくなる。
【００９４】
また、表３に示す評価結果から、サンプル１０〜サンプル１２では、負極合剤層にガス吸収剤を１１重量％含有させたサンプル１４に比べ、電池容量が大きくなっていることがわかる。
【００９５】
サンプル１４では、サンプル９と同様に、合剤層に含有されるガス吸収剤が多すぎて負極合剤層に含有される負極活物質の割合を少なくすることから、電池容量が小さくなる。
【００９６】
サンプル１３及びサンプル１４に対し、サンプル１０〜サンプル１２では、負極合剤層に含有されるガス吸収剤が０．２重量％以上、１０重量％以下の範囲であり、適切な量含有されていることから、電池内部に発生した炭酸ガス等を吸収して電池内にガスが貯留することを防ぎ、負極活物質も適宜な量含有されている。したがって、サンプル１０〜サンプル１２では、放電容量の低下と高温保存による電池特性の低下とが抑制される。
【００９７】
次に、上述したサンプル１〜サンプル３とは、ガス吸収剤の含有される場所をゲル状電解質に変えて製造したサンプル１５〜サンプル１９について説明する。
【００９８】
〈サンプル１５〉
サンプル１５では、ゲル状電解質を形成する際に、ＥＣとＰＣとを同重量比で混合させた非水溶媒に対してＬｉＰＦ_６を１ｍｏｌ／リットル溶解させた非水電解液９９．６重量部に、ガス吸収剤としてＬｉ_４ＳｉＯ_４粉末を０．４重量部分散させ、このＬｉ_４ＳｉＯ_４粉末が分散された非水電解液を３０重量部と、高分子マトリックスとしてポリ（ビニリデンフルオロライド−ｃｏ−ヘキサフルオロプロピレン）を１０重量部と、ジエチルカーボネートを６０重量部とを混合してゾル状態のゲル状電解質溶液を調製し、このゲル状電解質溶液を用いること以外は、サンプル１と同様にしてガス吸収剤が０．３重量％含有されたゲル状電解質を電極の合剤層上に形成した。そして、このゲル状電解質が形成された電極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【００９９】
〈サンプル１６〉
サンプル１６では、ゲル状電解質を形成する際に、ＥＣとＰＣとを同重量比で混合させた非水溶媒に対してＬｉＰＦ_６を１ｍｏｌ／リットル溶解させた非水電解液９０重量部に、ガス吸収剤としてＬｉ_４ＳｉＯ_４粉末を１０重量部分散させ、このＬｉ_４ＳｉＯ_４粉末が分散された非水電解液を３０重量部と、高分子マトリックスとしてポリ（ビニリデンフルオロライド−ｃｏ−ヘキサフルオロプロピレン）を１０重量部と、ジエチルカーボネートを６０重量部とを混合してゾル状態のゲル状電解質溶液を調製し、このゲル状電解質溶液を用いること以外は、サンプル１と同様にしてガス吸収剤が７．５重量％含有されたゲル状電解質を電極の合剤層上に形成した。そして、このゲル状電解質が形成された電極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【０１００】
〈サンプル１７〉
サンプル１７では、ゲル状電解質を形成する際に、ＥＣとＰＣとを同重量比で混合させた非水溶媒に対してＬｉＰＦ_６を１ｍｏｌ／リットル溶解させた非水電解液８０重量部に、ガス吸収剤としてＬｉ_４ＳｉＯ_４粉末を２０重量部分散させ、このＬｉ_４ＳｉＯ_４粉末が分散された非水電解液を３０重量部と、高分子マトリックスとしてポリ（ビニリデンフルオロライド−ｃｏ−ヘキサフルオロプロピレン）を１０重量部と、ジエチルカーボネートを６０重量部とを混合してゾル状態のゲル状電解質溶液を調製し、このゲル状電解質溶液を用いること以外は、サンプル１と同様にしてガス吸収剤が１５重量％含有されたゲル状電解質を電極の合剤層上に形成した。そして、このゲル状電解質が形成された電極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【０１０１】
〈サンプル１８〉
サンプル１８では、ゲル状電解質を形成する際に、ＥＣとＰＣとを同重量比で混合させた非水溶媒に対してＬｉＰＦ_６を１ｍｏｌ／リットル溶解させた非水電解液９９．８重量部に、ガス吸収剤としてＬｉ_４ＳｉＯ_４粉末を０．２重量部分散させ、このＬｉ_４ＳｉＯ_４粉末が分散された非水電解液を３０重量部と、高分子マトリックスとしてポリ（ビニリデンフルオロライド−ｃｏ−ヘキサフルオロプロピレン）を１０重量部と、ジエチルカーボネートを６０重量部とを混合してゾル状態のゲル状電解質溶液を調製し、このゲル状電解質溶液を用いること以外は、サンプル１と同様にしてガス吸収剤が０．１５重量％含有されたゲル状電解質を電極の合剤層上に形成した。そして、このゲル状電解質が形成された電極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【０１０２】
〈サンプル１９〉
サンプル１９では、ゲル状電解質を形成する際に、ＥＣとＰＣとを同重量比で混合させた非水溶媒に対してＬｉＰＦ_６を１ｍｏｌ／リットル溶解させた非水電解液７８．６重量部に、ガス吸収剤としてＬｉ_４ＳｉＯ_４粉末を２１．４重量部分散させ、このＬｉ_４ＳｉＯ_４粉末が分散された非水電解液を３０重量部と、高分子マトリックスとしてポリ（ビニリデンフルオロライド−ｃｏ−ヘキサフルオロプロピレン）を１０重量部と、ジエチルカーボネートを６０重量部とを混合してゾル状態のゲル状電解質溶液を調製し、このゲル状電解質溶液を用いること以外は、サンプル１と同様にしてガス吸収剤が１６重量％含有されたゲル状電解質を電極の合剤層上に形成した。そして、このゲル状電解質が形成された電極を用いたこと以外は、サンプル４と同様にして電池を製造した。
【０１０３】
そして、以上のように製造したサンプル１５〜サンプル１９の電池について、高温保存による膨れ量、放電容量、高温保存後の放電容量維持率を測定した。
【０１０４】
以下、各サンプルにおける、高温保存による膨れ量、放電容量、高温保存後の放電容量維持率の評価結果を表４に示す。
【０１０５】
【表４】

【０１０６】
なお、各サンプルおいて、高温保存による膨れ量は、上述したサンプル１〜サンプル４と同様にして測定した。また、放電容量及び高温保存後の放電容量維持率は、上述したサンプル５〜サンプル９と同様にして測定した。
【０１０７】
表４に示す評価結果から、ゲル状電解質にガス吸収剤を０．３重量％以上、１５重量％以下の範囲で含有させたサンプル１５〜サンプル１７では、ゲル状電解質にガス吸収剤を０．１５重量％含有させたサンプル１８に比べ、高温保存による膨れ量が小さく、高温保存後の放電容量維持率が大きくなっていることがわかる。
【０１０８】
サンプル１８では、ゲル状電解質に含有されるガス吸収剤が少なすぎることから、サンプル８と同様に、高温保存により電池内部に発生した炭酸ガス等を適切に吸収させることが困難であり、外装材が風船のように膨れて電池厚みが厚くなる。また、サンプル１８では、高温保存により正極合剤層及び負極合剤層の内部にも炭酸ガス等が発生し、この合剤層内のガスが集電体より合剤層を剥がしてしまうことから、高温保存後の電池容量が小さくなる。
【０１０９】
また、表４に示す評価結果から、サンプル１５〜サンプル１７では、ゲル状電解質にガス吸収剤を１６重量％含有させたサンプル１９に比べ、電池容量が大きくなっていることがわかる。
【０１１０】
サンプル１９では、サンプル９と同様に、ゲル状電解質に含有されるガス吸収剤が多すぎてゲル状電解質に含有されるＬｉＰＦ_６の割合を少なくなり、ＬｉＰＦ_６より解離するリチウムイオンが少ないことから、電池容量が小さくなる。
【０１１１】
サンプル１８及びサンプル１９に対し、サンプル１５〜サンプル１７では、ゲル状電解質に含有されるガス吸収剤が０．３重量％以上、１５重量％以下の範囲であり、適切な量含有されていることから、電池内部に発生した炭酸ガス等を吸収して電池内にガスが貯留することを防ぎ、ゲル状電解質中にＬｉＰＦ_６も適宜な量含有されている。したがって、サンプル１５〜サンプル１９では、放電容量の低下と高温保存による電池特性の低下とが抑制される。
【０１１２】
以上のことから、電池を製造する際に、ガス吸収剤を正極、負極、及びゲル状電解質に適切な量含有させることは、放電容量特性と高温保存特性とが両立されている優れた電池を製造する上で大変有効であることがわかる。
【０１１３】
【発明の効果】
以上の説明から明らかなように、本発明に係る非水電解質電池では、外装材に正極、負極及び非水電解質と一緒に封入されたガス吸収剤が、電池内部に発生したガスを吸収して電池内部にガスが貯留することを防止する。したがって、この非水電解質電池では、ガス吸収剤が内部に発生したガスを吸収することから、従来のような過充電、過放電及び高温保存された際に電池内に発生したガスが外装材を風船のように膨らませるといった不具合を防止できる。
【図面の簡単な説明】
【図１】本発明に係るリチウムイオン二次電池を示す透視斜視図である。
【図２】同リチウムイオン二次電池の内部構造を示す断面図である。
【符号の説明】
１ リチウムイオン二次電池、２ 電池素子、３ ガス吸収板、４ 外装材、５ 正極、６ 負極、７ 固体電解質、８ セパレータ、９ 正極集電体、１０正極合剤層、１１ 正極端子、１２ 負極集電体、１３ 負極合剤層、１４ 負極端子、１５ 基板、１６ ガス吸収剤層、１７ 樹脂片[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a nonaqueous electrolyte battery in which battery characteristics are significantly improved by suppressing deformation of an exterior material that collectively encapsulates a positive electrode, a negative electrode, and a nonaqueous electrolyte.
[0002]
[Prior art]
In recent years, as a power source of a portable electronic device such as a notebook portable computer, an information terminal device (PDA: Personal Digital Assistants), a portable telephone, and a camera-integrated VTR (Video Tape Recorder), a light and high energy density is used. Development of secondary batteries is underway. A secondary battery having a high energy density has a higher energy density than, for example, a lead battery or a nickel cadmium battery, and the charge / discharge reaction of the battery is performed by moving lithium ions between the positive electrode and the negative electrode. Such lithium ion secondary batteries are known.
[0003]
In this lithium ion secondary battery, for example, by using a film-like exterior material instead of a metal container or the like, it is possible to further reduce the thickness and weight. Specifically, in a lithium ion secondary battery, for example, a laminated film in which a heat-fusible polymer film and a metal foil are laminated is used as a film-shaped exterior material.
[0004]
[Problems to be solved by the invention]
However, in the above-described lithium ion secondary battery, a film made of a laminate film or the like used as an exterior material has lower rigidity than an exterior material such as a metal container. For this reason, in a lithium ion secondary battery, for example, when overcharging or overdischarging is performed due to erroneous operation of an electronic device, or when the battery is stored at a high temperature, a non-aqueous electrolyte solution or the like is decomposed in the battery and carbonated. Gas and the like are generated, and deform the film-like exterior material having low rigidity. Specifically, there is a problem that the film-shaped exterior material expands like a balloon due to gas generated in the battery.
[0005]
Therefore, the present invention has been proposed in view of such a conventional situation, and prevents the gas generated by overcharge, overdischarge, high-temperature storage, and the like from being stored inside the battery, and deforms the exterior material. It is an object of the present invention to provide a non-aqueous electrolyte battery in which is suppressed.
[0006]
[Means for Solving the Problems]
The nonaqueous electrolyte battery according to the present invention includes a positive electrode including a positive electrode mixture layer containing a positive electrode active material, a negative electrode including a negative electrode mixture layer containing a negative electrode active material, and a nonaqueous solvent and an electrolyte salt. Non-aqueous electrolyte and chemical formula Li _x Si _y O _z (Where x, y, and z are greater than 0) and Li _x Zr _y O _z (Where x, y, and z are greater than 0), a gas absorbent comprising any one or more of the lithium-containing oxides, a positive electrode, a negative electrode, a nonaqueous electrolyte, and a gas absorbent. And an exterior material to be enclosed in a lump.
[0007]
In this non-aqueous electrolyte battery, the gas absorbent enclosed in the exterior material together with the electrodes etc. absorbs the gas generated inside the battery and prevents the gas from being stored inside the battery. The exterior material is prevented from being deformed by the generated gas.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a non-aqueous electrolyte battery to which the present invention is applied will be described. FIG. 1 shows a configuration example of a lithium ion secondary battery (hereinafter, referred to as a battery) as the nonaqueous electrolyte battery. The battery 1 includes a battery element 2 serving as a power generation element, a gas absorbing plate 3 provided on an outer peripheral portion of the battery element 2, and a film-shaped exterior material 4 enclosing the battery element 2 and the gas absorbing plate 3 collectively. Have.
[0009]
As shown in FIG. 2, the battery element 2 has a band-shaped positive electrode 5 and a band-shaped negative electrode 6 with a solid electrolyte 7 containing an organic polymer or an electrolyte salt and a separator 8 interposed therebetween. It functions as a power generating element by being wound in the longitudinal direction of the strip-shaped electrode.
[0010]
The positive electrode 5 is coated with a positive electrode mixture coating solution containing a positive electrode active material and a binder on the positive electrode current collector 9, dried, and pressed to form a positive electrode mixture layer 10 on the positive electrode current collector 9. It has a structure formed by compression. A positive electrode terminal 11 is connected to the positive electrode 5 at a predetermined position of the positive electrode current collector 9 so as to protrude in the width direction of the positive electrode current collector 9. For the positive electrode terminal 11, for example, a strip-shaped metal piece made of a conductive metal such as aluminum is used.
[0011]
For the positive electrode active material, for example, Li which can relatively increase the battery capacity is used. _x MO ₂ (Where M represents one or more transition metals such as Co, Ni, Mn, Fe, Al, V, and Ti, and x is in the range of 0.5 to 1.10). Use an oxide or the like. As the transition metal M constituting the lithium composite oxide, Co, Ni, Mn, or the like is preferable. As a specific example of such a lithium composite oxide, Li _x CoO ₂ , Li _x NiO ₂ , Li _x Ni _y Co _1-y O ₂ (Where 0 <y <1), LiMn ₂ O ₄ And the like. In addition, as the positive electrode active material, for example, Li which is inexpensive and has a stable crystal structure is used. _x M _y PO ₄ (Where M is at least one of Fe, Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B, Nb, SnCa, and Sr; .Ltoreq.x.ltoreq.1.1 and 0.5.ltoreq.y.ltoreq.1). ₄ And so on. Further, as the positive electrode active material, for example, TiS ₂ , MoS ₂ , NbSe ₂ , V ₂ O ₅ And other metal sulfides or oxides.
[0012]
In the positive electrode 5, as a binder of the positive electrode mixture layer 10, for example, a binder such as polyvinylidene fluoride, polyvinylpyridine, polytetrafluoroethylene, or the like used in the positive electrode mixture of the nonaqueous electrolyte battery can be used. For example, a carbonaceous material or the like as a conductive material or a known additive or the like can be added to the positive electrode mixture layer 10. In the positive electrode 5, for the positive electrode current collector 9, for example, a foil-like metal or a net-like metal made of a conductive metal such as aluminum is used.
[0013]
The negative electrode 6 forms a negative electrode mixture layer 13 on the negative electrode current collector 12 by applying a negative electrode mixture coating liquid containing a negative electrode active material and a binder on the negative electrode current collector 12, drying, and pressing. It has a structure formed by compression. A negative electrode terminal 14 is connected to the negative electrode 6 at a predetermined position on the negative electrode current collector 12 so as to protrude in the width direction of the negative electrode current collector 12. For the negative electrode terminal 14, a strip-shaped metal piece made of a conductive metal such as nickel or copper is used.
[0014]
As the negative electrode active material, a material having a potential of 2 V or less with respect to lithium and doping / dedoping lithium is used. Specifically, for example, lithium, a lithium alloy, or a carbonaceous material capable of doping / dedoping lithium ions is used. Examples of the carbonaceous material that can be doped / undoped with lithium ions include a low-crystalline carbon material obtained by firing at a relatively low temperature of 2000 ° C. or less, and artificial graphite obtained by firing a raw material that easily crystallizes at a high temperature of about 3000 ° C. It is possible to use a highly crystalline carbon material or the like. Specifically, carbonaceous materials such as pyrolytic carbons, cokes, graphites, glassy carbon fibers, organic polymer compound fired bodies, carbon fibers, and activated carbon can be used. Examples of cokes include pitch coke, needle coke, petroleum coke, and the like. The organic polymer compound fired body is obtained by firing a phenol resin, a furan resin, or the like at an appropriate temperature and carbonizing the same.
[0015]
In addition, as the negative electrode active material, for example, an element that can be combined with lithium, a compound of this element, or the like can be used in addition to the above-described carbonaceous material. Specifically, for example, the chemical formula D _s E _t Li _u (D is one or more of a metal element and / or a semiconductor element which can be combined with lithium, E is one or more of a metal element and / or a semiconductor element other than lithium and D, s is larger than 0, t and u Is 0 or more.) As a compound represented by the chemical formula, SiB ₄ , SiB ₆ , Mg ₂ Si, Mg ₂ Sn, Ni ₂ Si, TiSi ₂ , MoSi ₂ , CoSi ₂ , NiSi ₂ , CaSi ₂ , CrSi ₂ , Cu ₅ Si, FeSi ₂ , MnSi ₂ , NbSi ₂ , TaSi ₂ , VSi ₂ , WSi ₂ , ZnSi ₂ And any one or more of these. These compounds can be used as a mixture of one or more of the above-described carbonaceous materials. In this case, the carbonaceous material functions as a conductive material.
[0016]
In addition to the above-mentioned carbonaceous materials and compounds, as the negative electrode active material, for example, a polymer such as polyacetylene or polypyrrole, or a relatively potential such as iron oxide, ruthenium oxide, molybdenum oxide, tungsten oxide, titanium oxide, tin oxide, or the like is used. It is also possible to use an oxide that is base and capable of doping and undoping lithium, a nitride obtained by replacing oxygen of these oxides with nitrogen, and the like.
[0017]
In the negative electrode 6, as the binder of the negative electrode mixture layer 11, for example, a binder such as polyvinylidene fluoride, polyvinylpyridine, polytetrafluoroethylene, or the like used in the negative electrode mixture of the nonaqueous electrolyte battery can be used. In the negative electrode 6, for the negative electrode current collector 12, for example, a foil-like metal or a net-like metal made of a conductive metal such as copper is used.
[0018]
The solid electrolyte 7 exchanges, for example, lithium ions between the positive electrode 5 and the negative electrode 6. Therefore, an organic solid electrolyte having lithium ion conductivity is used as the solid electrolyte 7. As the organic solid electrolyte, a polymer solid electrolyte composed of an electrolyte salt and an organic polymer containing the same, a gel electrolyte in which a non-aqueous electrolyte is contained in a polymer matrix, and the like can be used. The solid electrolyte 7 is formed as an electrolyte layer by applying and solidifying an electrolyte solution containing an organic solid electrolyte on the surfaces of the positive electrode 5 and the negative electrode 6.
[0019]
In the solid electrolyte 7, an electrolyte salt usually used for a non-aqueous electrolyte battery can be used. Specifically, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiClO ₄ , LiB (C ₆ H ₅ ) ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, LiC ₄ F ₉ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiC (SO ₂ CF ₃ ) ₃ , LiAlCl ₄ , LiSiF ₆ , LiCl, LiBr and the like, and one or more of these are used as a mixture. In particular, as an electrolyte salt, LiPF which is excellent in oxidation stability is used. ₆ , LiBF ₄ Is used.
[0020]
In the solid electrolyte 7, as an organic polymer containing an electrolyte salt of a polymer solid electrolyte, for example, an ether polymer such as poly (ethylene oxide) or the same crosslinked product, a poly (methacrylate) ester polymer, and an acrylate polymer A polymer or the like can be used alone or in the form of a mixture in a molecule.
[0021]
In the case of the gel electrolyte, in the solid electrolyte 7, a solvent having a relatively high dielectric constant is used as a non-aqueous solvent for dissolving the above-mentioned electrolyte salt to form a non-aqueous electrolyte. In this case, the non-aqueous electrolyte functions as a plasticizer. Specifically, as the non-aqueous solvent, for example, ethylene carbonate, propylene carbonate, γ-butyl lactone, diethyl carbonate, dimethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methylsulfolane, acetonitrile, propionitrile, acetate, butyrate, propionate, and the like. Mix and use a plurality of types.
[0022]
In the solid electrolyte 7, various polymers can be used as the polymer matrix containing the non-aqueous electrolyte of the gel electrolyte as long as it absorbs the non-aqueous electrolyte and gels. Specifically, for example, fluoropolymers such as poly (vinylidenefluoride) and poly (vinylidenefluoride-co-hexafluoropropylene), and ether polymers such as poly (ethylene oxide) and cross-linked products thereof , Poly (acrylonitrile) and the like, and any one or a mixture of these may be used.
[0023]
The separator 8 separates the positive electrode 5 and the negative electrode 6 from each other, and a known material that is generally used as an insulating porous film of this type of nonaqueous electrolyte battery can be used. Specifically, for example, a polymer film such as polypropylene or polyethylene is used. Further, from the relationship between the lithium ion conductivity and the energy density, it is preferable that the thickness of the separator 8 is as thin as possible, and the separator 8 is used with a thickness of 30 μm or less. Thereby, in the battery 1, the lithium ion conductivity between the positive electrode 5 and the negative electrode 6 can be improved, and a high energy density can be obtained.
[0024]
The gas absorbing plate 3 provided on the outer peripheral portion of the battery element 2 having the above-described configuration applies a gas absorbent coating solution containing a gas absorbent onto the substrate 15, drying and pressurizing the gas absorbent. The absorbent layer 16 has a structure formed by compression.
[0025]
In the gas absorbing plate 3, as the gas absorbing agent, for example, the chemical formula Li _x Si _y O _z (Where x, y, and z are greater than 0) and Li _x Zr _y O _z (Where x, y, and z are greater than 0), and the like. ₄ SiO ₄ , Li ₂ SiO ₃ , Li ₂ ZrO ₃ And the like. In the gas absorbing plate 3, since the substrate 15 is insulated from the battery element 2, various sheet-like materials such as a metal foil and an organic resin film can be used. In the gas absorbing plate 3, as the binder for forming the gas absorbing layer 16 containing the gas absorbent on the substrate 15, the above-described binder used for the positive electrode 5 and the negative electrode 6 may be used. Is possible.
[0026]
The gas absorbing plate 3 having such a configuration is sealed in the exterior material 4 together with the battery element 2 so that, for example, when the battery 1 falls into an overcharged state, an overdischarged state, or is exposed to a high-temperature environment. Then, carbon dioxide and the like generated by decomposition of the solid electrolyte 7 and the like are absorbed. Thereby, the gas absorbing plate 3 acts to prevent the gas generated by the decomposition of the solid electrolyte 7 and the like from being stored inside the battery, and to suppress the deformation of the exterior material 4 due to the gas generated inside the battery.
[0027]
The exterior material 4 that encloses the battery element 2 and the gas absorbing plate 3 in a lump is a laminated film in which a resin layer and a metal layer are bonded together by lamination or the like to be composited into two or more layers. The surface facing the element 2 is made to be a resin layer. The material of the resin layer is not particularly limited as long as it has an adhesive property to the positive electrode terminal 11 and the negative electrode terminal 14. For example, polyethylene, polypropylene, modified polyethylene, modified polypropylene and copolymers thereof, polyolefin resin and the like Such an organic resin material can be used because of its low permeability and excellent airtightness. As the metal layer, for example, aluminum, stainless steel, nickel, iron, or the like formed into a foil shape, a plate shape, or the like is used. In addition, in the case 4, by providing a resin layer made of, for example, nylon or the like on the layer serving as the outer peripheral layer of the battery 1, it is possible to improve the strength against breakage or piercing.
[0028]
The battery 1 having such a configuration is manufactured as follows. First, the positive electrode 5 is manufactured. When producing the positive electrode 5, a positive electrode mixture coating solution containing the above-described positive electrode active material, conductive material, and binder is prepared, and the positive electrode mixture coating solution is made of, for example, a positive electrode current collector made of aluminum foil or the like. The positive electrode mixture layer 10 is compressed and formed by uniformly applying, drying, and pressing so as to provide an uncoated portion on 9 and cut into a predetermined size. Next, the positive electrode terminal 11 is connected to the uncoated portion where the positive electrode current collector 9 is exposed, for example, by ultrasonic welding or spot welding. Thus, the belt-shaped positive electrode 5 is manufactured.
[0029]
Next, the negative electrode 6 is manufactured. When preparing the negative electrode 6, a negative electrode mixture coating solution containing the above-described negative electrode active material and a binder is prepared, and the negative electrode mixture coating solution is placed on a negative electrode current collector 12 made of, for example, copper foil or the like. The negative electrode mixture layer 13 is compression-formed by uniformly applying, drying, and pressing so as to provide an uncoated portion, and cut into predetermined dimensions. Next, the negative electrode terminal 14 is connected to the uncoated portion where the negative electrode current collector 12 is exposed, for example, by ultrasonic welding or spot welding. Thus, the strip-shaped negative electrode 6 is manufactured.
[0030]
Next, the solid electrolytes 7 are formed in layers on the main surface of the positive electrode mixture layer 10 of the positive electrode 5 and the main surface of the negative electrode mixture layer 13 of the negative electrode 6 manufactured as described above. When forming the solid electrolyte 7, an electrolyte salt is dissolved in a non-aqueous solvent to prepare a non-aqueous electrolyte. Next, this non-aqueous electrolyte, an organic polymer or a matrix polymer, and a non-aqueous solvent as a diluting solvent are mixed and stirred as necessary to prepare an electrolyte solution in a sol state. 5 and the main surface of the negative electrode mixture layer 13 of the negative electrode 6 to form a polymer solid electrolyte layer. When a diluting solvent is used, the non-aqueous solvent is volatilized to form a gel electrolyte layer. Thus, the solid electrolyte 7 is formed on the positive electrode 5 and the negative electrode 6 as an electrolyte layer.
[0031]
Next, the positive electrode 5 and the negative electrode 6 having the solid electrolyte 7 formed on the main surface as described above are wound many times in the longitudinal direction via the separator 8 so as to face the electrolyte layers, and are flatly wound. The battery element 2 is manufactured. In the battery element 2, the positive electrode terminal 11 and the negative electrode terminal 14 are protruded from one end face in the winding axis direction.
[0032]
Next, the gas absorbing plate 3 is manufactured. When producing the gas absorbing plate 3, a gas absorbent coating liquid containing the above-described gas absorbent and the binder is prepared, and the gas absorbent coating liquid is uniformly applied to, for example, a film-like substrate 15. By drying, pressurizing, the gas absorbent layer 16 is compression-formed and cut into predetermined dimensions. Thus, the sheet-shaped gas absorbing plate 3 is manufactured.
[0033]
Next, the battery element 3 and the gas absorbing plate 3 were collectively housed inside the exterior member 4 while the positive electrode terminal 11 and the negative electrode terminal 14 provided in the battery element 2 were led out. At this time, the battery element 2 is housed in the package 4 so that a resin piece 17 made of propylene or the like having adhesiveness is applied between the positive electrode terminal 11 and the negative electrode terminal 14 and the package 4. As a result, in the battery 1, a short circuit between the positive electrode terminal 11 and the negative electrode terminal 14 and the metal layer of the exterior material 4, a reduction in airtightness, and the like are prevented.
[0034]
Next, the battery element 2 is sealed in the exterior material 4 by bonding the peripheral edges of the exterior material 4 in which the battery element 2 and the gas absorbing plate 3 are housed by, for example, heat sealing or the like. Thus, the battery 1 including the gas absorbing plate 3 is manufactured.
[0035]
In the battery 1 manufactured as described above, the gas absorbing plate 3 sealed together with the battery element 2 in the outer package 4 absorbs the gas generated inside the battery and stores the gas inside the battery. Can be prevented.
[0036]
Therefore, in the battery 1, since the gas generated inside the battery 1 is absorbed by the gas absorbent contained in the gas absorbing plate 3, when the battery 1 is overcharged, overdischarged and stored at a high temperature, for example, non-aqueous It is possible to prevent a problem that carbon dioxide gas or the like generated by decomposition of the electrolyte or the like causes the exterior material to expand like a balloon.
[0037]
Further, in the battery 1, since the gas absorbent provided in the battery also absorbs the gas and the like stored between the stacked positive electrode 5 and the negative electrode 6 and the inside of the mixture layer, for example, the positive electrode 5 and the negative electrode 6 It is possible to prevent gas stored in the gap or inside the mixture layer from peeling the mixture layer from the current collector.
[0038]
In the above example, the battery 1 including the gas absorbing plate 3 containing the gas absorbing agent has been described. However, the gas absorbing plate 3 in which the gas absorbing agent-containing gas absorbing layer 16 is formed on the substrate 15 is not necessarily required. It is not limited to use. For example, the above-described gas can be used even when a powdery gas absorbent is compacted or when the powdery gas absorbent is directly encapsulated in an exterior material together with the battery element 2. The effect of the absorbent can be obtained.
[0039]
In the battery 1, for example, by forming the positive electrode mixture layer 10 using a positive electrode mixture coating liquid in which a gas absorbent is dispersed, the gas absorbent may be contained in the positive electrode mixture layer 10 of the positive electrode 5. It is possible. Thereby, in the battery 1, the gas absorbing plate 3 becomes unnecessary, and the thickness can be reduced.
[0040]
In this case, the gas absorbent is contained in the positive electrode mixture layer 10 in a range of 0.1% by weight or more and 8% by weight or less. When the amount of the gas absorbent contained in the positive electrode mixture layer 10 is less than 0.1% by weight, it is difficult to absorb carbon dioxide gas and the like generated inside the battery because the amount of the gas absorbent is too small. On the other hand, when the amount of the gas absorbent contained in the positive electrode mixture layer 10 is more than 8% by weight, the amount of the gas absorbent contained in the positive electrode mixture layer 10 is too large, and the positive electrode active material is contained in the positive electrode mixture layer 10. Since the included ratio decreases, the battery capacity decreases.
[0041]
Therefore, in the battery 1, when the positive electrode mixture layer 10 contains a gas absorbent, the positive electrode mixture layer 10 contains the gas absorbent in a range of 0.1% by weight or more and 8% by weight or less. This can suppress swelling due to carbon dioxide gas or the like generated inside and a decrease in battery capacity.
[0042]
Further, in the battery 1, for example, by forming the negative electrode mixture layer 13 using a negative electrode mixture coating liquid in which a gas absorbent is dispersed, the gas absorbent may be contained in the negative electrode mixture layer 13 of the negative electrode 6. It is possible. This battery 1 can also be made thinner, similarly to the case where the positive electrode mixture layer 10 contains a gas absorbent.
[0043]
In this case, the gas absorbent is contained in the negative electrode mixture layer 13 in a range of 0.2% by weight or more and 10% by weight or less. When the amount of the gas absorbent contained in the negative electrode mixture layer 13 is less than 0.2% by weight, it is difficult to absorb carbon dioxide gas and the like generated inside the battery 1 because the amount of the gas absorbent is too small. On the other hand, when the amount of the gas absorbent contained in the negative electrode mixture layer 13 is more than 10% by weight, the amount of the gas absorbent contained in the negative electrode mixture layer 13 is too large, and the negative electrode active material is contained in the negative electrode mixture layer 13. Since the included ratio decreases, the battery capacity decreases.
[0044]
Therefore, in the battery 1, when the negative electrode mixture layer 13 contains a gas absorbent, the negative electrode mixture layer 13 contains the gas absorbent in a range of 0.2% by weight or more and 10% by weight or less. This can suppress swelling due to carbon dioxide gas or the like generated inside and a decrease in battery capacity.
[0045]
Furthermore, in the battery 1, for example, the solid electrolyte 7 can be made to contain a gas absorbent by forming the solid electrolyte 7 using an electrolyte solution in which a gas absorbent is dispersed. This battery 1 can also be made thinner, similarly to the case where the positive electrode mixture layer 10 contains a gas absorbent.
[0046]
In this case, the gas absorbent is contained in the solid electrolyte 7 in a range of 0.3% by weight or more and 15% by weight or less. When the amount of the gas absorbent contained in the solid electrolyte 7 is less than 0.3% by weight, it is difficult to absorb carbon dioxide and the like generated inside the battery 1 because the amount of the gas absorbent is too small. On the other hand, when the amount of the gas absorbent contained in the solid electrolyte 7 is more than 15% by weight, the amount of the solid electrolyte 7 that contributes to charge and discharge decreases, and the battery capacity decreases.
[0047]
Therefore, in the battery 1, when the solid electrolyte 7 contains a gas absorbent, the solid electrolyte 7 contains the gas absorbent in a range of 0.3% by weight or more and 15% by weight or less, so that the internal Swelling due to carbon dioxide gas or the like, and a decrease in battery capacity can be suppressed.
[0048]
In the above description, the solid electrolyte 7 composed of a polymer solid electrolyte layer or a gel electrolyte layer is used as the non-aqueous electrolyte. However, the present invention is not limited to this. For example, an electrolyte salt may be used as the non-aqueous electrolyte. The present invention is also applicable to a case where a non-aqueous electrolyte dissolved in water is used. In the above-described embodiment, the thin battery 1 is described as an example. However, the present invention is not limited to this. For example, the battery may be a cylindrical shape, a coin shape, a square shape, a button shape, or the like. The present invention is also applicable to nonaqueous electrolyte batteries of various shapes and sizes, such as batteries using a metal container or the like as a material.
[0049]
【Example】
Hereinafter, a sample in which a lithium ion secondary battery is actually manufactured as a nonaqueous electrolyte battery to which the present invention is applied will be described.
[0050]
<Sample 1>
In sample 1, first, a positive electrode was manufactured. When producing a positive electrode, LiCoO as a positive electrode active material ₂ , 91 parts by weight of graphite, 6 parts by weight of graphite as a conductive material, 3 parts by weight of polyvinylidene fluoride (hereinafter, referred to as PVdF) as a binder, and N-methyl-2-pyrrolidone (hereinafter, NMP) as a solvent. ) And kneaded with a planetary mixer for dispersion to prepare a positive electrode mixture coating liquid. Next, using a die coater as a coating device, a 20 μm-thick strip-shaped aluminum foil serving as a positive electrode current collector was uniformly coated so as to provide uncoated portions on both sides, and dried at 100 ° C. under reduced pressure for 24 hours. Thereafter, the positive electrode mixture layer was formed by compression molding with a roll press machine, and cut into predetermined dimensions. Next, a positive electrode terminal obtained by cutting a metal net formed by knitting aluminum wires having a diameter of 50 μm at intervals of 75 μm to a predetermined size was connected to an uncoated portion where the positive electrode current collector was exposed by resistance welding. Thus, a long positive electrode was produced.
[0051]
Next, a negative electrode was manufactured. When preparing the negative electrode, 90 parts by weight of graphite powder serving as a negative electrode active material, 10 parts by weight of PVdF as a binder, and NMP to a solvent, kneading and dispersing by a planetary mixer, A negative electrode mixture coating liquid was prepared. Next, this negative electrode mixture coating liquid was uniformly applied using a die coater as a coating device so as to provide uncoated portions on both sides of a 10 μm-thick strip-shaped copper foil serving as a negative electrode current collector. After being dried in this state for 24 hours, the negative electrode mixture layer was formed by compression molding with a roll press machine and cut into predetermined dimensions. Next, to the uncoated portion where the negative electrode current collector was exposed, a negative electrode terminal obtained by cutting a metal net formed by knitting nickel wires having a diameter of 50 μm at intervals of 75 μm into predetermined dimensions was connected by resistance welding. Thus, a long negative electrode was produced.
[0052]
Next, a gel electrolyte was formed as an electrolyte layer on both main surfaces of the positive electrode and the negative electrode manufactured as described above. When forming an electrolyte layer made of a gel electrolyte, LiPF is mixed with a non-aqueous solvent obtained by mixing ethylene carbonate (EC) and propylene carbonate (PC) at the same weight ratio. ₆ Was dissolved at 1 mol / liter to prepare a non-aqueous electrolyte solution. Next, 30 parts by weight of this non-aqueous electrolyte, 10 parts by weight of poly (vinylidenefluoride-co-hexafluoropropylene) as a polymer matrix, and 60 parts by weight of diethyl carbonate are mixed and stirred to form a sol. Was prepared. Next, this gel electrolyte solution was applied on both main surfaces of the positive electrode and the negative electrode, respectively, and impregnated into the positive electrode mixture layer and the negative electrode mixture layer, and then allowed to stand at room temperature for 8 hours to volatilize diethyl carbonate. Was. Thus, an electrolyte layer composed of a gel electrolyte was formed on both the main surfaces of the positive electrode and the negative electrode.
[0053]
Next, the positive electrode and the negative electrode each having the electrolyte layer formed on the main surface as described above are attached to each other via a 15 μm separator made of a microporous polypropylene film so that the gel electrolyte faces each other. To form a battery element. Next, a gas absorbing plate was manufactured. When producing a gas absorbing plate, a gas absorbent coating liquid containing the above-described gas absorbent and a binder is prepared, and the gas absorbent coating liquid is uniformly applied to, for example, a film-like substrate, and dried. By pressurizing, the gas absorbent layer is compression-formed and cut into predetermined dimensions. Thus, the sheet-shaped gas absorbing plate 3 is manufactured.
[0054]
Next, Li as a gas absorbing agent was placed inside the exterior material made of a three-layer laminated film in which this battery element was sandwiched between a metal layer made of an aluminum foil having a thickness of 50 μm and a resin layer made of a polyolefin film having a thickness of 30 μm. ₄ SiO ₄ Stored with 0.5 g of powder. At this time, the battery element is packaged so that the positive electrode terminal and the negative electrode terminal are led out to the outside, and a propylene resin piece having adhesiveness is applied between the positive electrode terminal and the negative electrode terminal led out and the package material. It was stored in the material.
[0055]
Next, the battery element and the gas absorbent are housed inside and the peripheral parts of the exterior material are bonded together so that the resin layers face each other, and the bonded resin layers are hot-sealed at 200 ° C. The battery element and the gas absorbent were sealed in an exterior material. As described above, a thin lithium ion secondary battery was manufactured. In the following description, a lithium ion secondary battery is simply referred to as a battery for convenience.
[0056]
<Sample 2>
In sample 2, Li ₄ SiO ₄ Li as a gas absorbent instead of powder ₂ SiO ₃ Using this powder, this Li ₂ SiO ₃ A battery was fabricated in the same manner as in Sample 1, except that the powder was sealed in an exterior material together with the battery element.
[0057]
<Sample 3>
In sample 3, Li ₄ SiO ₄ Li as a gas absorbent instead of powder ₂ ZrO ₃ Using this powder, this Li ₂ ZrO ₃ A battery was fabricated in the same manner as in Sample 1, except that the powder was sealed in an exterior material together with the battery element.
[0058]
<Sample 4>
In sample 4, a battery was manufactured in the same manner as in sample 1, except that only the battery element was sealed in the package without using a gas absorbent.
[0059]
Then, for the batteries of Samples 1 to 4 manufactured as described above, the swollen amount due to high-temperature storage was measured.
[0060]
Table 1 below shows the results of evaluation of the amount of swelling due to high-temperature storage in each sample.
[0061]
[Table 1]

[0062]
The amount of swelling due to high-temperature storage was measured as follows. Each sample was charged at a constant current and constant voltage of up to 4.2 V at a charging current of 0.2 C, and then overcharged at a constant current and constant voltage of up to 4.35 at a charging current of 0.5 C. Next, after measuring the thickness of each overcharged sample, it was stored in a 100 ° C. atmosphere for 100 hours. Next, after storing at a high temperature, the thickness of each sample cooled to room temperature was measured again. Thus, the swelling amount due to high-temperature storage was measured. The amount of swelling of each sample due to high-temperature storage is the difference in battery thickness before and after high-temperature storage.
[0063]
From the evaluation results shown in Table 1, the swelling caused by high-temperature storage was higher in Samples 1 to 3 in which the gas absorbing agent was sealed in the outer package together with the battery element than in Sample 4 in which the gas absorbing agent was not sealed in the outer packaging. It can be seen that the amount has been significantly reduced.
[0064]
In sample 4, since there is no gas absorbent inside the battery and the gas generated inside the battery is not absorbed, the carbon dioxide gas generated by the decomposition of the gel electrolyte and the like due to overcharging or high-temperature storage is stored inside the battery, and the film is removed. The battery-like exterior material is inflated like a balloon, and the battery thickness is greatly increased.
[0065]
On the other hand, in Samples 1 to 3, the gas absorbent is enclosed together with the battery element inside the battery, and the gas absorbent absorbs the gas generated in the battery, so that the battery is overcharged or stored at a high temperature. The carbon dioxide gas generated by the decomposition of the gel electrolyte or the like is prevented from being stored inside the battery, and the thickness of the battery is prevented from being increased due to overcharge or high-temperature storage. Therefore, in Samples 1 to 3, the amount of swelling due to high-temperature storage is significantly smaller than in Sample 4.
[0066]
From the above, when manufacturing a battery, encapsulating the gas absorbent together with the battery element inside the battery is very effective in manufacturing an excellent battery in which the amount of swelling due to high-temperature storage is suppressed. You can see that there is.
[0067]
Next, the above-mentioned samples 1 to 3 will be described as samples 5 to 9 manufactured by changing the place where the gas absorbent is contained to the positive electrode mixture layer.
[0068]
<Sample 5>
In sample 5, when producing a positive electrode, LiCoO ₂ 90.9 parts by weight and Li as a gas absorbent ₄ SiO ₄ , 0.1 part by weight of graphite, 6 parts by weight of graphite as a conductive material, 3 parts by weight of PVdF as a binder, and NMP as a solvent to prepare a positive electrode mixture coating solution, and then disperse the mixture. A positive electrode was prepared in the same manner as in Sample 1, except that the mixture coating liquid was used, in which the positive electrode mixture layer contained 0.1% by weight of the gas absorbent. Then, a battery was manufactured in the same manner as in Sample 4, except that this positive electrode was used.
[0069]
<Sample 6>
In Sample 6, when producing the positive electrode, LiCoO ₂ 86 parts by weight and Li as a gas absorbent ₄ SiO ₄ , 5 parts by weight of graphite, 6 parts by weight of graphite as a conductive material, 3 parts by weight of PVdF as a binder, and NMP as a solvent to prepare a positive electrode mixture coating solution. A positive electrode was prepared in the same manner as in Sample 1, except that the coating liquid was used, in which the positive electrode mixture layer contained 5% by weight of a gas absorbent. Then, a battery was manufactured in the same manner as in Sample 4, except that this positive electrode was used.
[0070]
<Sample 7>
In sample 7, when producing a positive electrode, LiCoO ₂ 83 parts by weight and Li as a gas absorbent ₄ SiO ₄ , 8 parts by weight of graphite, 6 parts by weight of graphite as a conductive material, 3 parts by weight of PVdF as a binder, and NMP as a solvent to prepare a positive electrode mixture coating solution, which is then dispersed. A positive electrode was prepared in the same manner as in Sample 1 except that the coating solution was used, in which the positive electrode mixture layer contained a gas absorbent at 8% by weight. Then, a battery was manufactured in the same manner as in Sample 4, except that this positive electrode was used.
[0071]
<Sample 8>
In sample 8, when producing the positive electrode, LiCoO ₂ 90.95 parts by weight and Li as a gas absorbent ₄ SiO ₄ , 0.05 parts by weight of graphite, 6 parts by weight of graphite as a conductive material, 3 parts by weight of PVdF as a binder, and NMP as a solvent to prepare a positive electrode mixture coating solution. A positive electrode was prepared in the same manner as in Sample 1, except that the mixture coating liquid was used, in which the positive electrode mixture layer contained 0.05% by weight of the gas absorbent. Then, a battery was manufactured in the same manner as in Sample 4, except that this positive electrode was used.
[0072]
<Sample 9>
In sample 9, when producing the positive electrode, LiCoO ₂ 82 parts by weight and Li as a gas absorbent ₄ SiO ₄ , 9 parts by weight of graphite, 6 parts by weight of graphite as a conductive material, 3 parts by weight of PVdF as a binder, and NMP as a solvent to prepare a positive electrode mixture coating solution. A positive electrode was prepared in the same manner as in Sample 1, except that the coating liquid was used, and the positive electrode mixture layer contained 9% by weight of a gas absorbent. Then, a battery was manufactured in the same manner as in Sample 4, except that this positive electrode was used.
[0073]
Then, for the batteries of Samples 5 to 9 manufactured as described above, the swelling amount at high temperature storage, the discharge capacity, and the discharge capacity retention rate after high temperature storage were measured.
[0074]
Table 2 below shows the evaluation results of the swelling amount, discharge capacity, and discharge capacity retention rate after high-temperature storage in each sample.
[0075]
[Table 2]

[0076]
In each sample, the amount of swelling due to high-temperature storage was measured in the same manner as in Samples 1 to 4 described above. In addition, the discharge capacity and the discharge capacity retention rate after high-temperature storage were measured as follows. Each sample was charged with a constant current of 1 A, a charging voltage of 4.2 V, and a constant current and constant voltage of 3 hours, and a constant current of 0.2 A and a discharge end voltage of 2.5 V. Charging and discharging were performed under the discharging and charging conditions, and the initial discharge capacity was measured. Next, each sample charged under the same conditions as the first charge was stored in a 55 ° C. atmosphere for 500 hours, and after storage, was discharged under the same conditions as the first discharge. Next, each sample discharged after the high-temperature storage was charged and discharged under the initial charging and discharging conditions, and the discharge capacity after the high-temperature storage was measured. The discharge capacity is the initial discharge capacity measured as described above, and the discharge capacity retention rate after high-temperature storage is the ratio of the discharge capacity retention rate after high-temperature storage to the initial discharge capacity.
[0077]
From the evaluation results shown in Table 2, in Samples 5 to 7, in which the positive electrode mixture layer contained the gas absorbent in the range of 0.1% by weight or more and 8% by weight or less, the gaseous absorbent was contained in the positive electrode mixture layer. It can be seen that the swollen amount by high-temperature storage is smaller and the discharge capacity retention rate after high-temperature storage is larger than that of Sample 8 containing 0.05% by weight.
[0078]
In sample 8, since the amount of the gas absorbent contained in the positive electrode mixture layer was too small, it was difficult to properly absorb carbon dioxide gas and the like generated inside the battery due to high-temperature storage, and the exterior material was like a balloon. The battery swells and the battery thickness increases. In sample 8, carbon dioxide gas is also generated inside the positive electrode mixture layer and the negative electrode mixture layer due to high temperature storage, and the gas in the mixture layer peels off the mixture layer from the current collector. And the battery capacity after high-temperature storage is reduced.
[0079]
Further, from the evaluation results shown in Table 2, it is understood that the battery capacities of Samples 5 to 7 are larger than those of Sample 9 in which the positive electrode mixture layer contains 9% by weight of the gas absorbent.
[0080]
In sample 9, since the amount of the gas absorbent contained in the positive electrode mixture layer was too large and the proportion of the positive electrode active material contained in the positive electrode mixture layer was reduced, the battery capacity was reduced.
[0081]
In Samples 5 to 7, as compared to Samples 8 and 9, the gas absorbent contained in the positive electrode mixture layer is in the range of 0.1% by weight or more and 8% by weight or less, and is contained in an appropriate amount. For this reason, carbon dioxide or the like generated inside the battery is absorbed to prevent the gas from being stored in the battery, and the cathode active material is also contained in an appropriate amount. Therefore, in Samples 5 to 7, a decrease in discharge capacity and a decrease in battery characteristics due to high-temperature storage are suppressed.
[0082]
Next, the above-mentioned samples 1 to 3 will be described as samples 10 to 14 manufactured by changing the place where the gas absorbent is contained to the negative electrode mixture layer.
[0083]
<Sample 10>
In sample 10, when preparing the negative electrode, 89.8 parts by weight of graphite powder and Li as a gas absorbent were used. ₄ SiO ₄ , 0.2 parts by weight, 10 parts by weight of PVdF as a binder, and NMP as a solvent were added and dispersed to prepare a negative electrode mixture coating liquid, except that this negative electrode mixture coating liquid was used. In the same manner as in Sample 1, a negative electrode in which the negative electrode mixture layer contained 0.2% by weight of the gas absorbent was produced. Then, a battery was manufactured in the same manner as in Sample 4, except that this negative electrode was used.
[0084]
<Sample 11>
In sample 11, when preparing the negative electrode, 84 parts by weight of graphite powder and Li as a gas absorbent were used. ₄ SiO ₄ , 6 parts by weight of PVdF, 10 parts by weight of PVdF as a binder, and NMP as a solvent to prepare a negative electrode mixture coating liquid, and then use this negative electrode mixture coating liquid. In the same manner as in the above, a negative electrode in which a gas absorbent was contained in the negative electrode mixture layer at 6% by weight was produced. Then, a battery was manufactured in the same manner as in Sample 4, except that this negative electrode was used.
[0085]
<Sample 12>
In Sample 12, when preparing the negative electrode, 80 parts by weight of graphite powder and Li as a gas absorbent were used. ₄ SiO ₄ 10 parts by weight, 10 parts by weight of PVdF as a binder, and NMP as a solvent to prepare a negative electrode mixture coating liquid, and then use the negative electrode mixture coating liquid. In the same manner as in the above, a negative electrode in which a gas absorbent was contained at 10% by weight in the negative electrode mixture layer was produced. Then, a battery was manufactured in the same manner as in Sample 4, except that this negative electrode was used.
[0086]
<Sample 13>
In sample 13, when preparing the negative electrode, 89.9 parts by weight of graphite powder and Li as a gas absorbent were used. ₄ SiO ₄ 0.1 part by weight, 10 parts by weight of PVdF as a binder, and NMP as a solvent were added and dispersed to prepare a negative electrode mixture coating liquid, except that this negative electrode mixture coating liquid was used. In the same manner as in Sample 1, a negative electrode in which the negative electrode mixture layer contained 0.1% by weight of the gas absorbent was produced. Then, a battery was manufactured in the same manner as in Sample 4, except that this negative electrode was used.
[0087]
<Sample 14>
In Sample 14, when preparing the negative electrode, 79 parts by weight of graphite powder and Li as a gas absorbent were used. ₄ SiO ₄ , 11 parts by weight of PVdF, 10 parts by weight of PVdF as a binder, and NMP as a solvent to prepare a negative electrode mixture coating liquid, and then use the negative electrode mixture coating liquid. In the same manner as in the above, a negative electrode in which a gas absorbent was contained at 11% by weight in the negative electrode mixture layer was produced. Then, a battery was manufactured in the same manner as in Sample 4, except that this negative electrode was used.
[0088]
Then, for the batteries of Samples 10 to 14 manufactured as described above, the swelling amount due to high-temperature storage, the discharge capacity, and the discharge capacity retention rate after high-temperature storage were measured.
[0089]
Table 3 below shows the evaluation results of the swelling amount, discharge capacity, and discharge capacity retention rate after high-temperature storage in each sample.
[0090]
[Table 3]

[0091]
In each sample, the amount of swelling due to high-temperature storage was measured in the same manner as in Samples 1 to 4 described above. The discharge capacity and the discharge capacity retention rate after high-temperature storage were measured in the same manner as in Samples 5 to 9 described above.
[0092]
From the evaluation results shown in Table 3, in Samples 10 to 12, in which the gas mixture was contained in the negative electrode mixture layer in a range of 0.2% by weight or more and 10% by weight or less, the gas mixture was contained in the negative electrode mixture layer. It can be seen that the amount of swelling due to high-temperature storage is smaller than that of Sample 13 containing 0.1% by weight, and the discharge capacity retention rate after high-temperature storage is large.
[0093]
In sample 13, since the amount of the gas absorbent contained in the negative electrode mixture layer is too small, it is difficult to appropriately absorb carbon dioxide and the like generated inside the battery due to high-temperature storage, as in sample 8, The material swells like a balloon and the battery thickness increases. In sample 13, carbon dioxide gas and the like are also generated inside the positive electrode mixture layer and the negative electrode mixture layer due to high temperature storage, and the gas in this mixture layer peels off the mixture layer from the current collector. And the battery capacity after high-temperature storage is reduced.
[0094]
Further, from the evaluation results shown in Table 3, it can be seen that the battery capacity of Samples 10 to 12 is larger than that of Sample 14 in which the negative electrode mixture layer contains 11% by weight of the gas absorbent.
[0095]
In sample 14, similarly to sample 9, the battery capacity is reduced because the amount of the gas absorbent contained in the mixture layer is too large and the proportion of the negative electrode active material contained in the negative electrode mixture layer is reduced.
[0096]
In Samples 10 to 12, as compared to Samples 13 and 14, the gas absorbent contained in the negative electrode mixture layer is in a range of 0.2% by weight or more and 10% by weight or less, and is contained in an appropriate amount. For this reason, carbon dioxide and the like generated inside the battery are absorbed to prevent the gas from being stored in the battery, and the anode active material is contained in an appropriate amount. Therefore, in Samples 10 to 12, a decrease in discharge capacity and a decrease in battery characteristics due to high-temperature storage are suppressed.
[0097]
Next, the above-mentioned samples 1 to 3 will be described as samples 15 to 19 manufactured by changing the place where the gas absorbent is contained to a gel electrolyte.
[0098]
<Sample 15>
In Sample 15, when a gel electrolyte was formed, LiPF was mixed with a non-aqueous solvent in which EC and PC were mixed at the same weight ratio. ₆ Was dissolved in 99.6 parts by weight of a non-aqueous electrolyte in which 1 mol / liter of ₄ SiO ₄ 0.4 parts by weight of the powder is dispersed, and this Li ₄ SiO ₄ 30 parts by weight of the non-aqueous electrolyte in which the powder is dispersed, 10 parts by weight of poly (vinylidene fluoride-co-hexafluoropropylene) as a polymer matrix, and 60 parts by weight of diethyl carbonate are mixed to form a sol state. A gel electrolyte containing 0.3% by weight of a gas absorbent was formed on the mixture layer of the electrode in the same manner as in Sample 1 except that a gel electrolyte solution was prepared and the gel electrolyte solution was used. did. Then, a battery was manufactured in the same manner as in Sample 4, except that the electrode on which the gel electrolyte was formed was used.
[0099]
<Sample 16>
In Sample 16, when a gel electrolyte was formed, LiPF was mixed with a non-aqueous solvent in which EC and PC were mixed at the same weight ratio. ₆ Is dissolved as a gas absorbent in 90 parts by weight of a non-aqueous electrolyte in which 1 mol / liter is dissolved. ₄ SiO ₄ 10 parts by weight of the powder is dispersed, and this Li ₄ SiO ₄ 30 parts by weight of the non-aqueous electrolyte in which the powder is dispersed, 10 parts by weight of poly (vinylidene fluoride-co-hexafluoropropylene) as a polymer matrix, and 60 parts by weight of diethyl carbonate are mixed to form a sol state. A gel electrolyte containing 7.5% by weight of a gas absorbent was formed on the mixture layer of the electrode in the same manner as in Sample 1, except that a gel electrolyte solution was prepared. did. Then, a battery was manufactured in the same manner as in Sample 4, except that the electrode on which the gel electrolyte was formed was used.
[0100]
<Sample 17>
In Sample 17, when a gel electrolyte was formed, LiPF was mixed with a non-aqueous solvent in which EC and PC were mixed at the same weight ratio. ₆ Was dissolved as a gas absorbent in 80 parts by weight of a non-aqueous electrolyte in which ₄ SiO ₄ 20 parts by weight of the powder is dispersed, and this Li ₄ SiO ₄ 30 parts by weight of the non-aqueous electrolyte in which the powder is dispersed, 10 parts by weight of poly (vinylidene fluoride-co-hexafluoropropylene) as a polymer matrix, and 60 parts by weight of diethyl carbonate are mixed to form a sol state. Was prepared, and a gel electrolyte containing 15% by weight of a gas absorbent was formed on the mixture layer of the electrode in the same manner as in Sample 1 except that this gel electrolyte solution was used. Then, a battery was manufactured in the same manner as in Sample 4, except that the electrode on which the gel electrolyte was formed was used.
[0101]
<Sample 18>
In Sample 18, when a gel electrolyte was formed, LiPF was mixed with a non-aqueous solvent in which EC and PC were mixed at the same weight ratio. ₆ Was dissolved in 99.8 parts by weight of a non-aqueous electrolyte having 1 mol / liter dissolved therein as a gas absorbent. ₄ SiO ₄ 0.2 parts by weight of the powder is dispersed, and this Li ₄ SiO ₄ 30 parts by weight of the non-aqueous electrolyte in which the powder is dispersed, 10 parts by weight of poly (vinylidene fluoride-co-hexafluoropropylene) as a polymer matrix, and 60 parts by weight of diethyl carbonate are mixed to form a sol state. A gel electrolyte containing a gas absorbent of 0.15% by weight was formed on the mixture layer of the electrode in the same manner as in Sample 1, except that a gel electrolyte solution was prepared and the gel electrolyte solution was used. did. Then, a battery was manufactured in the same manner as in Sample 4, except that the electrode on which the gel electrolyte was formed was used.
[0102]
<Sample 19>
In Sample 19, when a gel electrolyte was formed, LiPF was mixed with a non-aqueous solvent in which EC and PC were mixed at the same weight ratio. ₆ Was added as a gas absorbent to 78.6 parts by weight of a non-aqueous electrolyte in which ₄ SiO ₄ The powder was dispersed in 21.4 parts by weight, and this Li ₄ SiO ₄ 30 parts by weight of the non-aqueous electrolyte in which the powder is dispersed, 10 parts by weight of poly (vinylidene fluoride-co-hexafluoropropylene) as a polymer matrix, and 60 parts by weight of diethyl carbonate are mixed to form a sol state. Was prepared in the same manner as in Sample 1 except that this gel electrolyte solution was used, and a gel electrolyte containing 16% by weight of the gas absorbent was formed on the mixture layer of the electrode. Then, a battery was manufactured in the same manner as in Sample 4, except that the electrode on which the gel electrolyte was formed was used.
[0103]
For the batteries of Samples 15 to 19 manufactured as described above, the swelling amount due to high-temperature storage, the discharge capacity, and the discharge capacity retention rate after high-temperature storage were measured.
[0104]
Table 4 shows the evaluation results of the swelling amount, discharge capacity, and discharge capacity retention rate after high-temperature storage in each sample.
[0105]
[Table 4]

[0106]
In each sample, the amount of swelling due to high-temperature storage was measured in the same manner as in Samples 1 to 4 described above. The discharge capacity and the discharge capacity retention rate after high-temperature storage were measured in the same manner as in Samples 5 to 9 described above.
[0107]
From the evaluation results shown in Table 4, in Samples 15 to 17 in which the gel electrolyte contained the gas absorbent in the range of 0.3% by weight or more and 15% by weight or less, the gel electrolyte contained the gas absorbent in the amount of 0.1% by weight. It can be seen that the swollen amount by high-temperature storage is smaller and the discharge capacity retention rate after high-temperature storage is larger than that of Sample 18 containing 15% by weight.
[0108]
In sample 18, since the amount of the gas absorbent contained in the gel electrolyte is too small, it is difficult to appropriately absorb carbon dioxide and the like generated inside the battery by high-temperature storage, similarly to sample 8, Expands like a balloon and the battery thickness increases. In sample 18, carbon dioxide gas and the like are also generated inside the positive electrode mixture layer and the negative electrode mixture layer due to high temperature storage, and the gas in the mixture layer peels off the mixture layer from the current collector. And the battery capacity after high-temperature storage is reduced.
[0109]
Also, from the evaluation results shown in Table 4, it can be seen that the battery capacity of Samples 15 to 17 is larger than that of Sample 19 in which the gel electrolyte contains 16% by weight of the gas absorbent.
[0110]
In sample 19, as in sample 9, the amount of gas absorbent contained in the gel electrolyte was too large and the amount of LiPF contained in the gel electrolyte was too large. ₆ Of LiPF ₆ Since less lithium ions are dissociated, the battery capacity is reduced.
[0111]
In contrast to Samples 18 and 19, in Samples 15 to 17, the gas absorbent contained in the gel electrolyte is in the range of 0.3% by weight or more and 15% by weight or less, and is contained in an appropriate amount. To absorb carbon dioxide and the like generated inside the battery to prevent the gas from being stored in the battery. ₆ Is also contained in an appropriate amount. Therefore, in Samples 15 to 19, a decrease in discharge capacity and a decrease in battery characteristics due to high-temperature storage are suppressed.
[0112]
From the above, when manufacturing a battery, including an appropriate amount of a gas absorbent in the positive electrode, the negative electrode, and the gel electrolyte can provide an excellent battery in which discharge capacity characteristics and high-temperature storage characteristics are compatible. It turns out that it is very effective in manufacturing.
[0113]
【The invention's effect】
As is clear from the above description, in the nonaqueous electrolyte battery according to the present invention, the gas absorbent sealed together with the positive electrode, the negative electrode, and the nonaqueous electrolyte in the exterior material absorbs the gas generated inside the battery. Prevents gas from accumulating inside the battery. Therefore, in this non-aqueous electrolyte battery, the gas absorbent absorbs the gas generated inside, and the gas generated in the battery during conventional overcharge, overdischarge and high-temperature storage acts as an exterior material. The problem of inflating like a balloon can be prevented.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a lithium ion secondary battery according to the present invention.
FIG. 2 is a sectional view showing an internal structure of the lithium ion secondary battery.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 lithium ion secondary battery, 2 battery element, 3 gas absorbing plate, 4 exterior material, 5 positive electrode, 6 negative electrode, 7 solid electrolyte, 8 separator, 9 positive electrode current collector, 10 positive electrode mixture layer, 11 positive electrode terminal, 12 Negative electrode current collector, 13 Negative electrode mixture layer, 14 Negative electrode terminal, 15 Substrate, 16 Gas absorbent layer, 17 Resin piece

Claims (5)

A positive electrode including a positive electrode mixture layer containing a positive electrode active material,
A negative electrode including a negative electrode mixture layer containing a negative electrode active material,
A non-aqueous electrolyte containing a non-aqueous solvent and an electrolyte salt,
(During wherein x, y, z is greater than 0.) Chemical formula _Li x _Si y _{O z or,} Li x _Zr y _{O z} (wherein x, y, z is greater than 0.) Represented by Among lithium-containing oxides, a gas absorbent consisting of any one or more,
A non-aqueous electrolyte battery comprising: the positive electrode, the negative electrode, the non-aqueous electrolyte, and a packaging material that collectively encapsulates the gas absorbent. The gas _{absorbent, Li 4 SiO 4, Li 2} SiO 3, non-aqueous electrolyte battery according to claim 1, wherein a is any one or more of Li 2 ZrO _3. 2. The nonaqueous electrolyte battery according to claim 1, wherein the gas absorbent is contained in the positive electrode mixture layer in a range from 0.1% by weight to 8% by weight. 3. 2. The non-aqueous electrolyte battery according to claim 1, wherein the gas absorbent is contained in the negative electrode mixture layer in a range of 0.2% by weight or more and 10% by weight or less. 2. The non-aqueous electrolyte battery according to claim 1, wherein the gas absorbent is contained in the non-aqueous electrolyte in a range of 0.3% by weight or more and 15% by weight or less.

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