JP5573812B2

JP5573812B2 - Battery manufacturing method

Info

Publication number: JP5573812B2
Application number: JP2011232874A
Authority: JP
Inventors: 直樹若松
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2011-10-24
Filing date: 2011-10-24
Publication date: 2014-08-20
Anticipated expiration: 2031-10-24
Also published as: JP2013093122A

Description

本発明は、自身の厚み方向に直交する一対の電極体主平面を有する、扁平状捲回型または積層型の電極体と、この電極体を収容し、一対の電極体主平面にそれぞれ対向する一対のケース内主面を含む一対のケース主壁部を有する電池ケースとを備える電池の製造方法に関する。 The present invention accommodates a flat wound-type or stacked-type electrode body having a pair of electrode body main planes orthogonal to the thickness direction of the electrode body, and each of the electrode bodies facing the pair of electrode body main planes. The present invention relates to a battery manufacturing method including a battery case having a pair of case main walls including a pair of case main surfaces.

従来より、扁平状捲回型または積層型の電極体と、この電極体を収容する電池ケースとを備える電池が知られている。扁平状捲回型または積層型の電極体は、自身の厚み方向に直交する一対の電極体主平面を有し、電池ケースは、これらの電極体主平面にそれぞれ対向する一対のケース内主面を含む一対のケース主壁部を有する。
このような電池の製造過程において、電池に初期充電を行うと、電解液の一部が分解してガスが発生する。その際、電池（その電極体）が厚み方向に圧縮されていないと、発生したガスの一部が電極体から抜けずに、正負極板間に溜まり易くなる。このガスは、正負極板間内で移動し離合集散を繰り返すため、正負極板間には、ガスが接しているために充電できない部分と、電解液に接していて充電できる部分とが現れ、しかも、これらの部分が移動する。このため、正負極板全体について初期充電するのに時間が長く掛かり、製造コストが高くなる。 2. Description of the Related Art Conventionally, a battery including a flat wound type or stacked type electrode body and a battery case that accommodates the electrode body is known. The flat wound type or laminated type electrode body has a pair of electrode body main planes orthogonal to its own thickness direction, and the battery case has a pair of case main surfaces facing the electrode body main planes, respectively. A pair of case main walls.
In such a battery manufacturing process, when the battery is initially charged, a part of the electrolytic solution is decomposed to generate gas. At that time, if the battery (the electrode body) is not compressed in the thickness direction, a part of the generated gas does not escape from the electrode body and tends to accumulate between the positive and negative electrode plates. Since this gas moves between the positive and negative electrode plates and repeats separation and concentration, a portion that cannot be charged because the gas is in contact between the positive and negative electrode plates and a portion that can be charged by being in contact with the electrolyte solution appear. Moreover, these parts move. For this reason, it takes a long time to initially charge the entire positive and negative electrode plates, and the manufacturing cost increases.

また、初期充電で発生したガスが、正負極板間に局所的に溜まり続ける場合もある。このようにガスが溜まった部分では、充放電反応が十分に進行せず、正負極板内で充放電反応が不均一になるため（反応ムラが生じるため）、電池容量や内部抵抗など電池の特性バラツキが大きくなる。
従って、初期充電を行う際には、電池外の圧縮具を用いて、電池のうち一対のケース主壁部間を挟んで、その一対のケース内主面で一対の電極体主平面をそれぞれ押圧し、電極体をその厚み方向に圧縮することにより、発生したガスが正負極板間に溜まり難くなるようにしていた。 In some cases, the gas generated by the initial charging continues to accumulate locally between the positive and negative electrode plates. In such a portion where gas is accumulated, the charge / discharge reaction does not proceed sufficiently and the charge / discharge reaction becomes uneven in the positive and negative electrode plates (because of uneven reaction), so the battery capacity, internal resistance, etc. Characteristic variation increases.
Therefore, when performing initial charging, a pair of case main wall portions of the battery are sandwiched between the pair of case main walls using a compression tool outside the battery, and the pair of electrode body main planes are respectively pressed by the pair of case main surfaces. Then, by compressing the electrode body in the thickness direction, the generated gas does not easily accumulate between the positive and negative electrode plates.

なお、関連する先行技術文献として、例えば特許文献１〜３が挙げられる。特許文献１には、扁平形状の捲回電極体が入れられた直方体形状の電池ケースのうち、一対の幅広面を両側から挟み込み、その挟み込み方向に電池ケースを押圧する拘束状態で、充電工程やエージング工程を行う旨が記載されている（特許文献１の特許請求の範囲、図２等を参照）。 In addition, as related prior art literature, patent documents 1-3 are mentioned, for example. In Patent Document 1, among a rectangular battery case in which a flat wound electrode body is inserted, a pair of wide surfaces are sandwiched from both sides, and in a restraint state in which the battery case is pressed in the sandwiching direction, The fact that an aging process is performed is described (see the claims of Patent Document 1, FIG. 2 and the like).

また、特許文献２には、積層型または捲回型の電極群を有する電池において、初回充電工程を実施するよりも前に、電池の厚さ方向の両側に固定板を配置して、この固定板により電池を挟持しておき、初回充電工程等で電池が膨張するのを抑制するのが好ましい旨が記載されている（特許文献２の段落（００５３）、図２等を参照）。
また、特許文献３には、初期充放電を行うよりも前に、２枚の拘束板で電池を厚み方向に拘束しておき、初期充放電等で電池の膨張を抑制する旨が記載されている（特許文献２の段落（００２４）、図２，５等を参照）。 Further, in Patent Document 2, in a battery having a stacked or wound electrode group, fixing plates are arranged on both sides in the thickness direction of the battery before the initial charging step is performed. It is described that it is preferable to hold the battery between the plates and suppress the expansion of the battery in the initial charging process or the like (see paragraph (0053) of FIG. 2 and FIG. 2).
Patent Document 3 describes that the battery is restrained in the thickness direction by two restraining plates before the initial charge / discharge, and the expansion of the battery is suppressed by the initial charge / discharge or the like. (See paragraph (0024) of FIGS. 2, 5 and 5, etc.).

特開２０１０−２１１０４号公報JP 2010-21104 A 特開２０１０−８０１０５号公報JP 2010-80105 A 特開２００８−２７７４１号公報JP 2008-27741 A

しかしながら、電池に圧縮具を装着した状態で初期充電を行うとすると、電池を量産するにあたって、多くの圧縮具が必要となる。また、圧縮具は、適切な圧縮力を発生し維持できるように、一般に金属製とされ、重くならざるを得ない。このため、電池に圧縮具を装着した状態で初期充電を行えるようにするには、その重量に耐え得る設備が必要となる。このため、生産設備のコストが高くなるという問題があった。 However, if initial charging is performed in a state in which the compression tool is mounted on the battery, many compression tools are required for mass production of the battery. In addition, the compression tool is generally made of metal and must be heavy so that an appropriate compression force can be generated and maintained. For this reason, in order to be able to perform initial charging in a state where the compression tool is attached to the battery, a facility capable of withstanding the weight is required. For this reason, there existed a problem that the cost of production equipment became high.

本発明は、かかる現状に鑑みてなされたものであって、初期充電の際に発生したガスが電極体の正負極板間に溜まるのを防止または抑制できると共に、生産設備のコストを低くできる電池の製造方法を提供することを目的とする。 The present invention has been made in view of the current situation, and can prevent or suppress the gas generated during the initial charging from accumulating between the positive and negative electrode plates of the electrode body, and can reduce the cost of production equipment. It aims at providing the manufacturing method of.

上記課題を解決するための本発明の一態様は、自身の厚み方向に直交する一対の電極体主平面を有する、扁平状捲回型または積層型の電極体と、前記電極体を収容し、一対の前記電極体主平面にそれぞれ対向する一対のケース内主面を含む一対のケース主壁部を有する電池ケースと、を備える電池の製造方法であって、前記電極体が収容された前記電池ケースの内圧を、大気圧Ｐａよりも減圧された内圧Ｐｂとした上で、前記電池ケースを気密に封止する減圧封止工程と、前記減圧封止工程の後、前記電池について初期充電を行う初期充電工程と、を備え、前記減圧封止工程は、電池外の圧縮具で前記電池のうち一対の前記ケース主壁部間を挟んで、一対の前記ケース内主面で一対の前記電極体主平面の全面を押圧して、前記電極体を前記厚み方向に圧縮した状態で行い、前記初期充電工程は、電池外の部材で前記ケース主壁部を押圧することなく、前記電池ケースの内外の気圧差により一対の前記ケース内主面で一対の前記電極体主平面の全面を押圧して、前記電極体を前記厚み方向に圧縮した状態で行う電池の製造方法である。 One aspect of the present invention for solving the above problems is a flat wound type or laminated type electrode body having a pair of electrode body main planes orthogonal to its thickness direction, and the electrode body, A battery case having a pair of case main walls including a pair of case main walls opposed to the pair of electrode body main planes, respectively, wherein the battery contains the electrode body The internal pressure of the case is set to an internal pressure Pb that is reduced from the atmospheric pressure Pa, and the battery case is hermetically sealed, and after the reduced pressure sealing step, the battery is initially charged. An initial charging step, wherein the decompression sealing step sandwiches a pair of case main wall portions of the battery with a compression tool outside the battery, and a pair of the electrode bodies on the pair of main surface in the case Pressing the entire main surface, the electrode body is The initial charging step is performed in a state compressed in the direction without pressing the case main wall portion with a member outside the battery, and a pair of the case inner main surfaces due to a difference in atmospheric pressure inside and outside the battery case. In this battery manufacturing method, the entire electrode body main plane is pressed to compress the electrode body in the thickness direction.

この電池の製造方法において、減圧封止工程では、圧縮具により、電池のうち一対のケース主壁部間を挟んで、その一対のケース内主面で一対の電極体主平面の全面をそれぞれ押圧し、電極体をその厚み方向に圧縮する。これにより、電極体主平面の全面が均一に押圧され、電極体がその厚み方向に均一に圧縮された状態（均一圧縮状態）となる。そして、この状態を保ちつつ、電池ケース内を内圧Ｐｂに減圧して封止する。すると、封止後の電池では、電池ケース内が負圧となるので、封止後に圧縮具を取り外しても、電池ケースの内外の気圧差によって、電極体が厚み方向に均一に圧縮された均一圧縮状態を維持できる。 In this method for manufacturing a battery, in the decompression and sealing step, the entire surface of the pair of electrode body main planes is pressed by the compression tool in the pair of case main walls across the pair of case main wall portions of the battery. Then, the electrode body is compressed in the thickness direction. Thereby, the entire surface of the electrode body main plane is uniformly pressed, and the electrode body is uniformly compressed in the thickness direction (uniform compression state). And while maintaining this state, the inside of the battery case is reduced to the internal pressure Pb and sealed. Then, in the battery after sealing, the inside of the battery case becomes negative pressure, so even if the compression tool is removed after sealing, the electrode body is uniformly compressed in the thickness direction due to the pressure difference between the inside and outside of the battery case. The compressed state can be maintained.

このため、その後、圧縮具など電池外の部材でケース主壁部を押圧することなく、初期充電を行っても、電池ケースの内外の気圧差によりケース内主面で電極体主平面の全面を押圧して電極体を厚み方向に圧縮した状態で、初期充電を行うことができる。従って、初期充電工程を行った際にガスが発生しても、このガスが正負極板間に溜まるのを防止または抑制できる。よって、初期充電に要する時間を短くでき、製造コストを低くできると共に、電池容量や内部抵抗など電池の特性バラツキが小さい電池を製造できる。一方、初期充電工程で圧縮具を用いなくて済むので、量産に要する圧縮具の数量を少なくできる、初期充電工程のための設備を簡素化できるなど、生産設備のコストを低くできる。 For this reason, after that, even if initial charging is performed without pressing the case main wall with a member outside the battery such as a compression tool, the entire main surface of the electrode body on the main surface inside the case due to the pressure difference inside and outside the battery case. Initial charging can be performed in a state where the electrode body is pressed and compressed in the thickness direction. Therefore, even if gas is generated during the initial charging step, it is possible to prevent or suppress the gas from accumulating between the positive and negative electrode plates. Therefore, the time required for initial charging can be shortened, the manufacturing cost can be reduced, and a battery with small variations in battery characteristics such as battery capacity and internal resistance can be manufactured. On the other hand, since it is not necessary to use a compression tool in the initial charging process, the number of the compression tools required for mass production can be reduced, and the equipment for the initial charging process can be simplified.

更に、上記の電池の製造方法であって、前記初期充電工程の後、前記電池についてエージングを行うエージング工程を備え、前記エージング工程は、電池外の部材で前記ケース主壁部を押圧することなく、前記電池ケースの内外の気圧差により一対の前記ケース内主面で一対の前記電極体主平面の全面を押圧して、前記電極体を前記厚み方向に圧縮した状態で行う電池の製造方法とすると良い。 Furthermore, the battery manufacturing method includes an aging process for aging the battery after the initial charging process, the aging process without pressing the case main wall with a member outside the battery. A battery manufacturing method in which the electrode bodies are compressed in the thickness direction by pressing the entire surface of the pair of electrode body main planes with a pair of main surface in the case by a pressure difference between inside and outside of the battery case; Good.

電池にエージングを行っている際にもガスが発生し得る。この場合も、電極体が厚み方向に圧縮されていないと、前述と同様、ガスの一部が正負極板間に溜まり易くなる。しかし、電池に圧縮具を装着した状態でエージングを行うとすると、エージングの期間中（例えば数日〜数十日程度にわたり）、圧縮具が必要になる。このため、特に多くの圧縮具が必要となる。また、エージングを行う設備も圧縮具の重量に耐え得る設備が必要となる。従って、生産設備のコストが特に高くなる。 Gas can also be generated during aging of the battery. Also in this case, if the electrode body is not compressed in the thickness direction, a part of the gas is likely to accumulate between the positive and negative electrode plates as described above. However, if aging is performed with the compression tool mounted on the battery, the compression tool is required during the aging period (for example, over several days to several tens of days). For this reason, especially many compression tools are needed. In addition, equipment that can withstand the weight of the compression tool is also required for aging. Therefore, the cost of production equipment is particularly high.

これに対し、この電池の製造方法では、前述の減圧封止工程を行うことで、封止後の電池では、電池ケースの内外の気圧差によって、電極体が厚み方向に均一に圧縮された均一圧縮状態を維持できる。このため、圧縮具など電池外の部材でケース主壁部を押圧することなく、エージングを行っても、電池ケースの内外の気圧差によりケース内主面で電極体主平面の全面を押圧して電極体を厚み方向に圧縮した状態で、エージングを行うことができる。従って、エージング工程を行った際にガスが発生しても、このガスが正負極板間に溜まるのを防止または抑制できる。よって、電池容量や内部抵抗など電池の特性バラツキが小さい電池を製造できる。一方、エージング工程で圧縮具を用いなくて済むので、量産に要する圧縮具の数量を少なくできる、エージング工程のための設備を簡素化できるなど、生産設備のコストを低くできる。
なお、「エージング」とは、所定の充電状態、所定のエージング温度で、所定のエージング時間、電池を安置する処理を指す。 On the other hand, in this battery manufacturing method, the electrode body is uniformly compressed in the thickness direction by the pressure difference between the inside and outside of the battery case in the sealed battery by performing the above-described decompression sealing step. The compressed state can be maintained. For this reason, even if aging is performed without pressing the case main wall with a member outside the battery such as a compression tool, the entire main surface of the electrode body is pressed on the main surface inside the case due to the pressure difference inside and outside the battery case. Aging can be performed with the electrode body compressed in the thickness direction. Therefore, even if a gas is generated during the aging process, the gas can be prevented or suppressed from accumulating between the positive and negative electrode plates. Therefore, a battery with small variations in battery characteristics such as battery capacity and internal resistance can be manufactured. On the other hand, since it is not necessary to use a compression tool in the aging process, the cost of production equipment can be reduced, for example, the quantity of the compression tool required for mass production can be reduced, and the equipment for the aging process can be simplified.
“Aging” refers to a process of placing a battery in a predetermined charging state and a predetermined aging temperature for a predetermined aging time.

更に、上記のいずれかに記載の電池の製造方法であって、前記減圧封止工程は、前記圧縮具により、前記電極体主平面に掛かる圧力Ｐｏが７５ｋＰａ以上となる力で前記電池を挟み、前記内圧Ｐｂを、大気圧Ｐａを基準としたゲージ圧表記で−７５ｋＰａ以下とする電池の製造方法とすると良い。 Furthermore, in the battery manufacturing method according to any one of the above, the decompression sealing step sandwiches the battery with a force at which a pressure Po applied to the electrode body main plane is 75 kPa or more by the compression tool. It is preferable that the internal pressure Pb is a battery manufacturing method in which the gauge pressure is expressed as not more than −75 kPa in terms of the atmospheric pressure Pa.

圧縮具によって電極体主平面に掛かる圧力Ｐｏを７５ｋＰａ以上とすることで、電極体が厚み方向に十分に圧縮された状態とすることができる。そして、内圧Ｐｂを−７５ｋＰａ以下として電池ケースを気密封止することで、封止後の電池ケースの内外の気圧差が十分に大きくなり、封止後の電池においても、電極体が厚み方向に十分に圧縮された状態とすることができる。従って、初期充電工程やエージング工程の際にガスが正負極板間に溜まるのをより効果的に防止できる。
なお、本明細書では、原則として、内圧Ｐｂ等を、絶対真空を基準（零点）とした絶対圧ではなく、大気圧を基準（零点）としたゲージ圧で記載する。 By setting the pressure Po applied to the electrode body main plane by the compression tool to 75 kPa or more, the electrode body can be sufficiently compressed in the thickness direction. Then, the battery case is hermetically sealed with an internal pressure Pb of −75 kPa or less, so that the pressure difference between the inside and outside of the battery case after sealing becomes sufficiently large, and even in the battery after sealing, the electrode body is in the thickness direction. It can be in a fully compressed state. Therefore, it is possible to more effectively prevent gas from accumulating between the positive and negative electrode plates during the initial charging process and the aging process.
In this specification, as a general rule, the internal pressure Pb and the like are described not by an absolute pressure based on an absolute vacuum (zero point) but by a gauge pressure based on an atmospheric pressure (zero point).

実施形態に係るリチウムイオン二次電池を示す斜視図である。It is a perspective view which shows the lithium ion secondary battery which concerns on embodiment. 実施形態に係るリチウムイオン二次電池を示す縦断面図である。It is a longitudinal cross-sectional view which shows the lithium ion secondary battery which concerns on embodiment. 実施形態に係り、電極体を示す斜視図である。It is a perspective view which concerns on embodiment and shows an electrode body. 実施形態に係るリチウムイオン二次電池の製造方法に関し、圧縮具により電池を挟んで電極体を厚み方向に圧縮した状態を示す断面図である。It is sectional drawing which shows the state which compressed the electrode body in the thickness direction on both sides of the battery with the compression tool regarding the manufacturing method of the lithium ion secondary battery which concerns on embodiment. 実施形態に係るリチウムイオン二次電池の製造方法に関し、圧縮具により電池を挟んで電極体を厚み方向に圧縮した状態を示す平面図である。It is a top view which shows the state which compressed the electrode body in the thickness direction on both sides of the battery with the compression tool regarding the manufacturing method of the lithium ion secondary battery which concerns on embodiment. 実施形態に係るリチウムイオン二次電池の製造方法に関し、減圧封止工程後、電池ケースの内外の気圧差によって、電極体が厚み方向に均一に圧縮された均一圧縮状態を示す断面図である。It is sectional drawing which shows the uniform compression state by which the electrode body was uniformly compressed in the thickness direction by the pressure difference inside and outside a battery case after the pressure reduction sealing process regarding the manufacturing method of the lithium ion secondary battery which concerns on embodiment. 実施形態に係るリチウムイオン二次電池に関し、減圧封止工程において電極体主平面に掛かる圧力Ｐｏと、初期充電工程において初期充電に要する初期充電時間との関係を示すグラフである。It is a graph which shows the relationship between the pressure Po concerning the electrode body main plane in a pressure-reduction sealing process, and the initial charge time required for initial charge in an initial charge process regarding the lithium ion secondary battery which concerns on embodiment.

以下、本発明の実施の形態を、図面を参照しつつ説明する。図１及び図２に、本実施形態に係るリチウムイオン二次電池１００（以下、単に電池１００とも言う）を示す。また、図３に、この電池１００を構成する扁平状捲回型の電極体１２０を示す。なお、図１及び図２における上方を電池１００の上側、下方を電池１００の下側として説明する。また、本実施形態では、電池１００並びにこれを構成する電池ケース１１０及び電極体１２０の厚み方向をＢＨ、幅方向をＣＨ、高さ方向をＤＨとして説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a lithium ion secondary battery 100 (hereinafter also simply referred to as a battery 100) according to the present embodiment. FIG. 3 shows a flat wound electrode body 120 that constitutes the battery 100. 1 and 2 will be described as the upper side of the battery 100, and the lower side will be described as the lower side of the battery 100. In the present embodiment, the battery 100 and the battery case 110 and the electrode body 120 constituting the battery 100 are described as having a thickness direction of BH, a width direction of CH, and a height direction of DH.

この電池１００は、ハイブリッド自動車や電気自動車等の車両や、ハンマードリル等の電池使用機器に搭載される角型電池である。この電池１００は、直方体形状の電池ケース１１０、この電池ケース１１０内に収容された扁平状捲回型の電極体１２０、電池ケース１１０に支持された正極端子１５０及び負極端子１６０等から構成されている（図１及び図２参照）。また、電池ケース１１０内には、非水系の電解液１１７が保持されている。 The battery 100 is a square battery that is mounted on a vehicle such as a hybrid vehicle or an electric vehicle, or a battery-powered device such as a hammer drill. The battery 100 includes a rectangular parallelepiped battery case 110, a flat wound electrode body 120 accommodated in the battery case 110, a positive terminal 150 and a negative terminal 160 supported by the battery case 110, and the like. (See FIGS. 1 and 2). In addition, a non-aqueous electrolyte solution 117 is held in the battery case 110.

このうち電池ケース１１０（図１及び図２参照）は、金属（具体的にはアルミニウム）により形成されている。この電池ケース１１０は、ケース上壁部１１０ａと、これに平行なケース下壁部１１０ｂと、これらの間を結ぶ４つのケース側壁部（第１ケース側壁部１１０ｃ、第２ケース側壁部１１０ｄ、第３ケース側壁部１１０ｅ及び第４ケース側壁部１１０ｆ）とからなる直方体形状をなす。 Of these, the battery case 110 (see FIGS. 1 and 2) is formed of metal (specifically, aluminum). The battery case 110 includes a case upper wall portion 110a, a case lower wall portion 110b parallel to the case upper wall portion, and four case side wall portions (first case side wall portion 110c, second case side wall portion 110d, A rectangular parallelepiped shape including the three case side wall portions 110e and the fourth case side wall portion 110f) is formed.

４つのケース側壁部のうち、第１ケース側壁部１１０ｃ及び第２ケース側壁部１１０ｄは、互いに平行に位置し、幅広で（幅方向ＣＨの寸法が大きく）最も面積の大きいケース壁部であり、前述の一対のケース主壁部に相当する。また、第１ケース側壁部１１０ｃのうち、電池内部に位置する第１ケース内側面１１０ｃｎ、及び、第２ケース側壁部１１０ｄのうち、電池内部に位置する第２ケース内側面１１０ｄｎが、前述の一対のケース内主面に相当する。第１，第２ケース側壁部１１０ｃ，１１０ｄは、その周縁部１１０ｃｍ，１１０ｄｍを除く中央平面部１１０ｃｇ，１１０ｄｇが、それぞれ厚み方向ＢＨに電池内部側に凹んで電池内部側に位置している。
また、残りの第３ケース側壁部１１０ｅ及び第４ケース側壁部１１０ｆは、互いに平行に位置し、幅狭で（幅方向ＣＨの寸法が小さく）面積の小さいケース壁部である。 Among the four case side wall portions, the first case side wall portion 110c and the second case side wall portion 110d are parallel to each other, are wide (the dimension in the width direction CH is large), and are the largest case wall portions. This corresponds to the pair of case main walls described above. In addition, the first case inner side surface 110cn located inside the battery among the first case side wall portions 110c and the second case inner side surface 110dn located inside the battery among the second case side wall portions 110d are the above-described pair. This corresponds to the main surface in the case. The first and second case side wall portions 110c and 110d have central flat portions 110cg and 110dg, excluding their peripheral portions 110cm and 110dm, respectively recessed in the thickness direction BH toward the inside of the battery and positioned on the inside of the battery.
The remaining third case side wall portion 110e and fourth case side wall portion 110f are case wall portions that are positioned in parallel to each other and have a small width (small dimension in the width direction CH) and a small area.

この電池ケース１１０は、ケース本体部材１１１とケース蓋部材１１３とから構成されている。このうちケース本体部材１１１は、前述のケース下壁部１１０ｂ及び４つのケース側壁部１１０ｃ，１１０ｄ，１１０ｅ，１１０ｆからなり、上側のみが開口した箱状をなす。また、ケース蓋部材１１３は、前述のケース上壁部１１０ａからなる矩形板状であり、ケース本体部材１１１の開口１１１ｈを閉塞する形態で、ケース本体部材１１１に溶接されている。 The battery case 110 includes a case main body member 111 and a case lid member 113. Of these, the case body member 111 is composed of the case lower wall portion 110b and the four case side wall portions 110c, 110d, 110e, and 110f, and has a box shape in which only the upper side is opened. The case lid member 113 is a rectangular plate formed of the above-described case upper wall portion 110a, and is welded to the case main body member 111 so as to close the opening 111h of the case main body member 111.

ケース蓋部材１１３には、その長手方向の中央付近に、電池ケース１１０の内圧が所定圧力に達した際に破断する非復帰型の安全弁１１３ｖが設けられている。
また、ケース蓋部材１１３のうち、この安全弁１１３ｖの近傍には、電解液１１７を電池ケース１１０内に注入するために用いられる注液孔１１３ｈが、ケース蓋部材１１３を貫通する形態で設けられている。この注液孔１１３ｈは、後述するように、電池ケース１１０内が大気圧Ｐａ（＝０ｋＰａ）よりも減圧された状態（負圧状態）で、封止部材１１５により気密に封止されている。この封止部材１１５は、電池ケース１１０の材質と同じ材質（具体的にはアルミニウム）からなる円板状をなし、注液孔１１３ｈを電池外部から覆う形態で、ケース蓋部材１１３に固着（具体的には溶接）されている。 The case lid member 113 is provided near the center in the longitudinal direction with a non-returnable safety valve 113v that breaks when the internal pressure of the battery case 110 reaches a predetermined pressure.
Further, in the case lid member 113, a liquid injection hole 113 h used for injecting the electrolytic solution 117 into the battery case 110 is provided near the safety valve 113 v so as to penetrate the case lid member 113. Yes. As will be described later, the liquid injection hole 113h is hermetically sealed by the sealing member 115 in a state where the inside of the battery case 110 is depressurized from the atmospheric pressure Pa (= 0 kPa) (negative pressure state). The sealing member 115 has a disk shape made of the same material (specifically, aluminum) as the material of the battery case 110, and is fixed to the case lid member 113 in a form that covers the liquid injection hole 113h from the outside of the battery (specifically Is actually welded).

また、ケース蓋部材１１３には、それぞれ電池ケース１１０の内部から外部に延出する形態の通電端子部材１５１からなる正極端子１５０及び負極端子１６０が固設されている。具体的には、正極端子１５０及び負極端子１６０は、これらにバスバーや圧着端子など電池外の端子を締結するためのボルト１５３，１５３と共に、樹脂からなる絶縁部材１５５，１５５を介して、ケース蓋部材１１３に固設されている（図２参照）。 In addition, the case lid member 113 is fixedly provided with a positive electrode terminal 150 and a negative electrode terminal 160 each including an energization terminal member 151 configured to extend from the inside of the battery case 110 to the outside. Specifically, the positive electrode terminal 150 and the negative electrode terminal 160 are connected to the case lid via insulating members 155 and 155 made of resin, together with bolts 153 and 153 for fastening terminals outside the battery such as bus bars and crimp terminals. It is fixed to the member 113 (see FIG. 2).

次に、扁平状捲回型の電極体１２０について説明する（図２及び図３参照）。この電極体１２０は、絶縁フィルムを上側のみが開口した袋状に形成した絶縁フィルム包囲体１１９内に収容され、横倒しにした状態で電池ケース１１０内に収容されている（図２参照）。この電極体１２０は、扁平状をなし、その厚み方向ＢＨに直交し、互いに平行で平面状をなす一対の電極体主平面（第１電極体主平面１２０ｃ及び第２電極体主平面１２０ｄ）と、これらを結び半円筒状をなす一対の半円筒面（第１半円筒面１２０ａ及び第２半円筒面１２０ｂ）とを有する。 Next, the flat wound electrode body 120 will be described (see FIGS. 2 and 3). The electrode body 120 is housed in an insulating film enclosure 119 formed in a bag shape having an insulating film opened only on the upper side, and is housed in the battery case 110 in a laid state (see FIG. 2). The electrode body 120 has a flat shape, a pair of electrode body main planes (a first electrode body main plane 120c and a second electrode body main plane 120d) that are orthogonal to the thickness direction BH and are parallel to each other to form a planar shape. , And a pair of semi-cylindrical surfaces (first semi-cylindrical surface 120a and second semi-cylindrical surface 120b) that form a semi-cylindrical shape.

このうち第１電極体主平面１２０ｃは、電池ケース１１０のうち第１ケース側壁部１１０ｃの第１ケース内側面（ケース内主面）１１０ｃｎに対向し、第２電極体主平面１２０ｄは、第２ケース側壁部１１０ｄの第２ケース内側面（ケース内主面）１１０ｄｎに対向している。また、第１半円筒面１２０ａは、ケース上壁部１１０ａ側に位置し、第２半円筒面１２０ｂは、ケース下壁部１１０ｂ側に位置している。 Among these, the first electrode body main plane 120c faces the first case inner side surface (case inner main surface) 110cn of the first case side wall 110c of the battery case 110, and the second electrode body main plane 120d is the second electrode body main plane 120d. The case side wall portion 110d faces the second case inner side surface (inner case main surface) 110dn. The first semi-cylindrical surface 120a is located on the case upper wall portion 110a side, and the second semi-cylindrical surface 120b is located on the case lower wall portion 110b side.

この電極体１２０は、帯状の正極板１２１と帯状の負極板１３１とを、多孔質膜からなる帯状の２枚のセパレータ１４１，１４１を介して互いに重ねて捲回し、扁平状に圧縮したものである（図３参照）。正極板１２１の幅方向の一部は、セパレータ１４１から軸線ＡＸ方向（電池１００等の幅方向ＣＨ）の一方側ＡＣに渦巻き状をなして突出しており、前述の正極端子１５０と接続している（図２参照）。また、負極板１３１の幅方向の一部は、セパレータ１４１から軸線ＡＸ方向（電池１００等の幅方向ＣＨ）の他方側ＡＤに渦巻き状をなして突出しており、前述の負極端子１６０と接続している（図２参照）。 This electrode body 120 is obtained by winding a belt-like positive electrode plate 121 and a belt-like negative electrode plate 131 on each other via two belt-like separators 141 and 141 made of a porous film, and compressing them flatly. Yes (see FIG. 3). A part of the positive electrode plate 121 in the width direction protrudes from the separator 141 in a spiral shape to one side AC in the axis AX direction (width direction CH of the battery 100 or the like) and is connected to the positive electrode terminal 150 described above. (See FIG. 2). In addition, a part of the negative electrode plate 131 in the width direction protrudes from the separator 141 to the other side AD in the axis AX direction (the width direction CH of the battery 100 or the like) in a spiral shape, and is connected to the negative electrode terminal 160 described above. (See FIG. 2).

次いで、上記電池１００の製造方法について説明する。
まず、安全弁１１３ｖ及び注液孔１１３ｈ等を形成したケース蓋部材１１３と、通電端子部材１５１，１５１と、ボルト１５３，１５３とを用意し、これらを射出成形用の金型にセットする。そして、射出成形により絶縁部材１５５，１５５を一体的に成形して、ケース蓋部材１１３に正極端子１５０及び負極端子１６０を固設する（図１及び図２参照）。 Next, a method for manufacturing the battery 100 will be described.
First, a case lid member 113 formed with a safety valve 113v, a liquid injection hole 113h, and the like, energizing terminal members 151 and 151, and bolts 153 and 153 are prepared, and these are set in an injection mold. Then, the insulating members 155 and 155 are integrally formed by injection molding, and the positive terminal 150 and the negative terminal 160 are fixed to the case lid member 113 (see FIGS. 1 and 2).

次に、別途形成した電極体１２０に、正極端子１５０及び負極端子１６０をそれぞれ接続（溶接）する。また、ケース本体部材１１１及び絶縁フィルム包囲体１１９を用意し、ケース本体部材１１１内に絶縁フィルム包囲体１１９を介して電極体１２０を収容すると共に、ケース本体部材１１１の開口１１１ｈをケース蓋部材１１３で塞ぐ。そして、レーザ溶接によりケース本体部材１１１とケース蓋部材１１３とを溶接して、電池ケース１１０を形成する（図１及び図２参照）。 Next, the positive electrode terminal 150 and the negative electrode terminal 160 are connected (welded) to the separately formed electrode body 120. In addition, a case body member 111 and an insulating film enclosure 119 are prepared. The electrode body 120 is accommodated in the case body member 111 via the insulation film enclosure 119, and the opening 111 h of the case body member 111 is formed in the case lid member 113. Close with. The case body member 111 and the case lid member 113 are welded by laser welding to form the battery case 110 (see FIGS. 1 and 2).

次に、この電池１００を真空チャンバ内に入れて真空チャンバ内を減圧する。そして、注液用ノズルを注液孔１１３ｈ内に挿入して、注液用ノズルから電池ケース１１０内に電解液１１７を注液する。注液後は、真空チャンバ内を大気圧に戻して、この電池１００を真空チャンバから取り出す。 Next, the battery 100 is placed in a vacuum chamber and the vacuum chamber is depressurized. Then, a liquid injection nozzle is inserted into the liquid injection hole 113h, and the electrolytic solution 117 is injected into the battery case 110 from the liquid injection nozzle. After the injection, the inside of the vacuum chamber is returned to atmospheric pressure, and the battery 100 is taken out from the vacuum chamber.

次に、減圧封止工程を行う。即ち、まず、電池外の圧縮具２００を用意し、これを電池１００に装着する（図４及び図５参照）。なお、図４，図５及び後述する図６においては、正極端子１５０、負極端子１６０等の図示を省略してある。
この圧縮具２００は、金属（具体的にはアルミニウム）からなる２枚の拘束板（第１拘束板２１０及び第２拘束板２２０)と、これらの拘束板２１０，２２０を連結するための４つのボルト２３１，２３１，…及びナット２３３，２３３，…とを有する。 Next, a reduced pressure sealing process is performed. That is, first, a compression tool 200 outside the battery is prepared and attached to the battery 100 (see FIGS. 4 and 5). 4 and 5 and FIG. 6 described later, illustration of the positive electrode terminal 150, the negative electrode terminal 160, and the like is omitted.
The compression tool 200 includes two restraint plates (first restraint plate 210 and second restraint plate 220) made of metal (specifically, aluminum) and four restraint plates 210 and 220 for connecting the restraint plates 210 and 220. , And nuts 233, 233,...

第１拘束板２１０は、板状部２１１と圧縮部２１３とからなる。このうち板状部２１１は、電池ケース１１０のケース主壁部（第１，第２ケース側壁部１１０ｃ，１１０ｄ）及び第１，第２ケース内主面１１０ｃｎ，１１０ｄｎよりも、幅方向ＣＨ及び高さ方向ＤＨの寸法がそれぞれ大きくされた矩形板状をなす。一方、圧縮部２１３は、ケース主壁部（第１，第２ケース側壁部１１０ｃ，１１０ｄ）及び第１，第２ケース内主面１１０ｃｎ，１１０ｄｎよりも、幅方向ＣＨ及び高さ方向ＤＨの寸法がそれぞれ小さく、かつ、第１，第２電極体主面１２０ｃ，１２０ｄよりも、幅方向ＣＨ及び高さ方向ＤＨの寸法がそれぞれ大きくされた矩形板状をなす。同様に、第２拘束板２２０も、板状部２２１と圧縮部２２３とからなる。 The first restraining plate 210 includes a plate-like portion 211 and a compression portion 213. Of these, the plate-like portion 211 has a width direction CH and a height higher than the case main wall portions (first and second case side wall portions 110c and 110d) and the first and second case inner main surfaces 110cn and 110dn of the battery case 110. It has a rectangular plate shape in which the dimension in the length direction DH is increased. On the other hand, the compression part 213 has dimensions in the width direction CH and the height direction DH rather than the case main wall parts (first and second case side wall parts 110c and 110d) and the first and second case main faces 110cn and 110dn. And a rectangular plate shape in which the dimensions in the width direction CH and the height direction DH are larger than those of the first and second electrode body main surfaces 120c and 120d, respectively. Similarly, the second restraint plate 220 also includes a plate-like portion 221 and a compression portion 223.

この圧縮具２００は、次のようにして電池１００に装着する（図４及び図５参照）。即ち、第１拘束板２１０の圧縮部２１３を、第１ケース側壁部１１０ｃに当接させると共に、第２拘束板２２０の圧縮部２２３を、第２ケース側壁部１１０ｄに当接させて、電池１００のうち第１ケース側壁部１１０ｃと第２ケース側壁部１１０ｄとの間を挟む。その際、圧縮部２１３の外周縁２１３ｆと第１ケース側壁部１１０ｃの外周縁１１０ｃｆとの間、及び、圧縮部２２３の外周縁２２３ａｆと第２ケース側壁部１１０ｄの外周縁１１０ｄｆとの間に、それぞれ所定の間隔ができるように位置合わせをして、第１，第２拘束板２１０，２２０を電池１００に配置する。 The compression tool 200 is attached to the battery 100 as follows (see FIGS. 4 and 5). That is, the compression part 213 of the first restraining plate 210 is brought into contact with the first case side wall part 110c, and the compression part 223 of the second restraining plate 220 is brought into contact with the second case side wall part 110d, so that the battery 100 is brought into contact. The first case side wall 110c and the second case side wall 110d are sandwiched. At that time, between the outer peripheral edge 213f of the compression part 213 and the outer peripheral edge 110cf of the first case side wall part 110c, and between the outer peripheral edge 223af of the compression part 223 and the outer peripheral edge 110df of the second case side wall part 110d, The first and second restraining plates 210 and 220 are arranged on the battery 100 by aligning them so as to have a predetermined interval.

その後、ボルト２３１，２３１，…及びナット２３３，２３３，…の締結により、第１拘束板２１０と第２拘束板２２０との間隔を狭めていき、第１，第２拘束板２１０，２２０の圧縮部２１３，２２３により第１，第２ケース側壁部１１０ｃ，１１０ｄをそれぞれ厚み方向ＢＨに電池内部側に凹ませて塑性変形させる。この塑性変形により、第１，第２ケース側壁部１１０ｃ，１１０ｄには、それぞれ電池内部側に位置する中央平面部１１０ｃｇ，１１０ｄｇと、それらの周囲をなす周縁部１１０ｃｍ，１１０ｄｍとが形成される。これと共に、第１，第２ケース側壁部１１０ｃ，１１０ｄのうち中央平面部１１０ｃｇ，１１０ｄｇの第１，第２ケース内主面１１０ｃｎ，１１０ｄｎが、電極体１２０の第１，第２電極体主平面１２０ｃ，１２０ｄの全面をそれぞれ押圧して、電極体１２０（詳細には、電極体１２０のうち第１，第２電極体主平面１２０ｃ，１２０ｄ間の部分）をその厚み方向ＢＨ（図４中、上下方向）に圧縮する。 After that, by fastening bolts 231, 231,... And nuts 233, 233,..., The distance between the first restraint plate 210 and the second restraint plate 220 is narrowed, and the first and second restraint plates 210, 220 are compressed. The first and second case side wall portions 110c and 110d are recessed in the thickness direction BH toward the inside of the battery by the portions 213 and 223, respectively, and are plastically deformed. Due to this plastic deformation, center plane portions 110cg and 110dg located on the inside of the battery and peripheral portions 110cm and 110dm surrounding them are formed on the first and second case side wall portions 110c and 110d, respectively. At the same time, the first and second case main surfaces 110 cn and 110 dn of the central plane portions 110 cg and 110 dg of the first and second case side wall portions 110 c and 110 d are the first and second electrode body main planes of the electrode body 120. 120c and 120d are respectively pressed to make the electrode body 120 (specifically, the portion between the first and second electrode body main planes 120c and 120d of the electrode body 120) in the thickness direction BH (in FIG. Compress in the vertical direction.

ボルト２３１，２３１，…及びナット２３３，２３３，…の締め付け具合は、第１，第２電極体主平面１２０ｃ，１２０ｄに掛かる圧力Ｐｏがそれぞれ７５ｋＰａ以上（具体的には８０ｋＰａ）となる力で、第１，第２拘束板２１０，２２０の圧縮部２１３，２２３が電池１００を挟むように調整する。このようにして圧縮具２００で電池１００を挟むことにより、第１，第２電極体主平面１２０ｃ，１２０ｄの全面がそれぞれ均一に押圧され、電極体１２０（そのうちの第１，第２電極体主平面１２０ｃ，１２０ｄ間の部分）が厚み方向ＢＨに均一に圧縮された状態（均一圧縮状態）となる。 The bolts 231, 231,... And the nuts 233, 233,... Are tightened by a force at which the pressure Po applied to the first and second electrode body main planes 120c, 120d is 75 kPa or more (specifically, 80 kPa). The compression parts 213 and 223 of the first and second restraining plates 210 and 220 are adjusted so as to sandwich the battery 100. By sandwiching the battery 100 with the compression tool 200 in this manner, the entire surfaces of the first and second electrode body main planes 120c and 120d are pressed uniformly, and the electrode body 120 (of which the first and second electrode body mains are included). The portion between the planes 120c and 120d) is uniformly compressed in the thickness direction BH (uniformly compressed state).

次に、この圧縮具２００を装着した電池１００を、真空チャンバ内に入れて真空チャンバ内を減圧する。本実施形態では、電池ケース１１０内の内圧Ｐｂを−７５ｋＰａ以下（具体的には−８０ｋＰａ）とする。そして、封止部材１１５を用意し、この封止部材１１５で注液孔１１３ｈを電池外部から覆い、更に、封止部材１１５を電池ケース１１０のケース蓋部材１１３に溶接して、封止部材１１５とケース蓋部材１１３との間を気密に封止する。これにより、電池ケース１１０が気密に封止される。減圧封止後は、真空チャンバ内を大気圧に戻して、この電池１００を真空チャンバから取り出す。 Next, the battery 100 equipped with the compression tool 200 is placed in a vacuum chamber to depressurize the vacuum chamber. In the present embodiment, the internal pressure Pb in the battery case 110 is set to −75 kPa or less (specifically −80 kPa). Then, a sealing member 115 is prepared, the injection hole 113 h is covered from the outside of the battery with the sealing member 115, and the sealing member 115 is welded to the case lid member 113 of the battery case 110. And the case lid member 113 are hermetically sealed. Thereby, the battery case 110 is hermetically sealed. After sealing under reduced pressure, the inside of the vacuum chamber is returned to atmospheric pressure, and the battery 100 is removed from the vacuum chamber.

このように電池ケース１１０内を減圧して封止すると、封止後の電池１００では、電池ケース１１０内が負圧となる。このため、図６に示すように、封止後に圧縮具２００を取り外しても、電池ケース１１０の内外の気圧差（具体的には約８０ｋＰａ）によって、第１，第２ケース内主面１１０ｃｎ，１１０ｄｎで第１，第２電極体主平面１２０ｃ，１２０ｄの全面がそれぞれ押圧されて、電極体１２０（そのうちの第１，第２電極体主平面１２０ｃ，１２０ｄ間の部分）が厚み方向ＢＨに均一に圧縮された均一圧縮状態を維持できる。 When the inside of the battery case 110 is reduced in pressure and sealed in this way, in the battery 100 after sealing, the inside of the battery case 110 becomes negative pressure. For this reason, as shown in FIG. 6, even if the compression tool 200 is removed after sealing, the first and second case main surfaces 110cn, due to the pressure difference between the inside and outside of the battery case 110 (specifically, about 80 kPa). 110dn presses the entire surfaces of the first and second electrode body main planes 120c and 120d, so that the electrode body 120 (the portion between the first and second electrode body main planes 120c and 120d) is uniform in the thickness direction BH. It is possible to maintain a uniform compression state compressed to a constant value.

次に、初期充電工程において、この電池１００について初期充電を行う。この初期充電工程は、圧縮具２００等の電池外の部材で第１，第２ケース側壁部１１０ｃ，１１０ｄを押圧することなく、電池ケース１１０の内外の気圧差により第１，第２ケース内主面１１０ｃｎ，１１０ｄｎで第１，第２電極体主平面１２０ｃ，１２０ｄの全面をそれぞれ押圧して、電極体１２０を厚み方向ＢＨに圧縮した状態（図６参照）で行う。 Next, in the initial charging step, the battery 100 is initially charged. In this initial charging step, the main parts in the first and second cases are not affected by the pressure difference between the inside and outside of the battery case 110 without pressing the first and second case side walls 110c and 110d with members outside the battery such as the compressor 200. The entire surface of the first and second electrode body main planes 120c and 120d is pressed by the surfaces 110cn and 110dn, respectively, and the electrode body 120 is compressed in the thickness direction BH (see FIG. 6).

この初期充電は、常温（２５℃）環境下で、定電流−定電圧方式により、ＳＯＣ１００％まで行う。具体的には、１Ｃ（具体的には５Ａ）の定電流で、電池電圧値が所定の充電終止電圧値４．１Ｖ（ＳＯＣ１００％のときの電池電圧値）に至るまで充電し、その後、電池電圧値を４．１Ｖに維持しつつ充電を行い、充電電流値が０．０２Ｃ（具体的には０．１Ａ）に低下した時点で初期充電を終了する。 This initial charging is performed up to SOC 100% by a constant current-constant voltage method in a normal temperature (25 ° C.) environment. Specifically, the battery is charged with a constant current of 1C (specifically, 5A) until the battery voltage value reaches a predetermined end-of-charge voltage value of 4.1V (battery voltage value when SOC is 100%). Charging is performed while maintaining the voltage value at 4.1 V, and the initial charging is terminated when the charging current value decreases to 0.02 C (specifically, 0.1 A).

この初期充電の際には、電解液１１７の一部が分解して水素ガスなどの気体（ガス）が発生する。しかし、本実施形態では、この初期充電の期間中、電極体１２０が厚み方向ＢＨに均一に圧縮された均一圧縮状態にあるので、発生したガスの殆ど全てが電極体１２０から抜け出る。このため、この初期充電工程でガスが正極板１２１と負極板１３１との間に溜まるのを防止できる。 During the initial charging, a part of the electrolytic solution 117 is decomposed to generate a gas (gas) such as hydrogen gas. However, in this embodiment, since the electrode body 120 is in a uniformly compressed state in which the electrode body 120 is uniformly compressed in the thickness direction BH during the initial charging period, almost all of the generated gas escapes from the electrode body 120. For this reason, it is possible to prevent gas from accumulating between the positive electrode plate 121 and the negative electrode plate 131 in this initial charging step.

次に、エージング工程において、この電池１００についてエージングを行う。このエージング工程は、前述の初期充電工程と同様に、圧縮具２００等の電池外の部材で第１，第２ケース側壁部１１０ｃ，１１０ｄを押圧することなく、電池ケース１１０の内外の気圧差により第１，第２ケース内主面１１０ｃｎ，１１０ｄｎで第１，第２電極体主平面１２０ｃ，１２０ｄの全面をそれぞれ押圧して、電極体１２０を厚み方向ＢＨに圧縮した状態（図６参照）で行う。
このエージングは、電池電圧値４．１Ｖ（ＳＯＣ１００％に相当）の状態にて、所定のエージング温度（具体的には５０℃）で、所定のエージング時間（具体的には１５時間）、電池１００を安置する。 Next, the battery 100 is aged in an aging process. Similar to the initial charging step described above, this aging step is performed by a pressure difference between the inside and outside of the battery case 110 without pressing the first and second case side wall portions 110c and 110d with a member outside the battery such as the compression tool 200. In a state where the entire first and second electrode body main planes 120c and 120d are pressed by the first and second case inner main surfaces 110cn and 110dn, respectively, and the electrode body 120 is compressed in the thickness direction BH (see FIG. 6). Do.
This aging is performed at a battery voltage value of 4.1 V (corresponding to SOC of 100%) at a predetermined aging temperature (specifically, 50 ° C.) at a predetermined aging time (specifically, 15 hours). Enshrine.

このエージングの際にも、電解液１１７の一部が分解して水素ガスなどの気体（ガス）が発生する場合がある。しかし、本実施形態では、このエージングの期間中においても、電極体１２０が厚み方向ＢＨに均一に圧縮された均一圧縮状態にあるので、発生したガスの殆ど全てが電極体１２０から抜け出る。このため、このエージング工程においても、ガスが正極板１２１と負極板１３１との間に溜まるのを防止できる。かくして、電池１００が完成する。 Even during the aging, a part of the electrolytic solution 117 may be decomposed to generate a gas (gas) such as hydrogen gas. However, in the present embodiment, even during the aging period, since the electrode body 120 is in a uniformly compressed state in which it is uniformly compressed in the thickness direction BH, almost all of the generated gas escapes from the electrode body 120. For this reason, it is possible to prevent gas from accumulating between the positive electrode plate 121 and the negative electrode plate 131 also in this aging process. Thus, the battery 100 is completed.

以上で説明したように、この電池１００の製造方法では、減圧封止工程において、圧縮具２００により、電池１００のうち一対のケース主壁部（第１，第２ケース側壁部）１１０ｃ，１１０ｄ間を挟んで、一対のケース内主面（第１，第２ケース内主面）１１０ｃｎ，１１０ｄｎで一対の電極体主平面（第１，第２電極体主平面）１２０ｃ，１２０ｄの全面をそれぞれ押圧して、電極体１２０をその厚み方向ＢＨに圧縮する。これにより、電極体主平面１２０ｃ，１２０ｄの全面がそれぞれ均一に押圧され、電極体１２０が厚み方向ＢＨに均一に圧縮された状態（均一圧縮状態）となる（図４参照）。そして、この状態を保ちつつ、電池ケース１１０を内圧Ｐｂに減圧して封止する。すると、封止後の電池１００では、電池ケース１１０内が負圧となるので、封止後に圧縮具２００を取り外しても、電池ケース１１０の内外の気圧差によって、電極体１２０が厚み方向ＢＨに均一に圧縮された均一圧縮状態を維持できる（図６参照）。 As described above, in the method for manufacturing the battery 100, in the decompression and sealing step, the compression tool 200 is used to place the pair of case main wall portions (first and second case side wall portions) 110 c and 110 d in the battery 100. A pair of inner main surfaces (first and second main surfaces) 110cn and 110dn press the entire surfaces of the pair of electrode main surfaces (first and second electrode main surfaces) 120c and 120d, respectively. Then, the electrode body 120 is compressed in the thickness direction BH. Thereby, the entire surfaces of the electrode body main planes 120c and 120d are pressed uniformly, and the electrode body 120 is uniformly compressed in the thickness direction BH (uniform compression state) (see FIG. 4). While maintaining this state, the battery case 110 is reduced to the internal pressure Pb and sealed. Then, in the battery 100 after sealing, the inside of the battery case 110 has a negative pressure. Therefore, even if the compression tool 200 is removed after sealing, the electrode body 120 is moved in the thickness direction BH due to a difference in atmospheric pressure inside and outside the battery case 110. A uniformly compressed state that is uniformly compressed can be maintained (see FIG. 6).

このため、その後、圧縮具２００など電池外の部材でケース主壁部１１０ｃ，１１０ｄを押圧することなく、初期充電を行っても、電池ケース１１０の内外の気圧差によりケース内主面１１０ｃｎ，１１０ｄｎで電極体主平面１２０ｃ，１２０ｄの全面をそれぞれ押圧して、電極体１２０を厚み方向ＢＨに圧縮した状態で、初期充電を行うことができる。従って、初期充電工程を行った際にガスが発生しても、このガスが正負極板１２１，１３１間に溜まるのを防止できる。よって、初期充電に要する時間を短くでき、製造コストを低くできると共に、電池容量や内部抵抗など電池の特性バラツキが小さい電池１００を製造できる。一方、初期充電工程で圧縮具２００を用いなくて済むので、量産に要する圧縮具２００の数量を少なくできる、初期充電工程のための設備を簡素化できるなど、生産設備のコストを低くできる。 Therefore, even if initial charging is performed without pressing the case main wall portions 110c and 110d with a member outside the battery such as the compression tool 200, the case inner main surfaces 110cn and 110dn due to the pressure difference inside and outside the battery case 110. Thus, initial charging can be performed in a state where the entire electrode body main surfaces 120c and 120d are pressed to compress the electrode body 120 in the thickness direction BH. Therefore, even if a gas is generated when the initial charging process is performed, the gas can be prevented from accumulating between the positive and negative electrode plates 121 and 131. Therefore, the time required for the initial charging can be shortened, the manufacturing cost can be reduced, and the battery 100 with small variations in battery characteristics such as battery capacity and internal resistance can be manufactured. On the other hand, since it is not necessary to use the compression tool 200 in the initial charging process, the number of the compression tools 200 required for mass production can be reduced, and the equipment for the initial charging process can be simplified.

更に、本実施形態では、初期充電工程と同様に、エージング工程も、圧縮具２００など電池外の部材でケース主壁部１１０ｃ，１１０ｄを押圧することなく、電池ケース１１０の内外の気圧差によりケース内主面１１０ｃ，１１０ｄで電極体主平面１２０ｃ，１２０ｄの全面をそれぞれ押圧して、電極体１２０を厚み方向ＢＨに圧縮した状態で行う。従って、エージング工程を行った際にガスが発生しても、このガスが正負極板１２１，１３１間に溜まるのを防止できる。よって、電池容量や内部抵抗など電池の特性バラツキが小さい電池１００を製造できる。一方、エージング工程で圧縮具２００を用いなくて済むので、量産に要する圧縮具２００の数量を少なくできる、エージング工程のための設備を簡素化できるなど、生産設備のコストを低くできる。 Further, in the present embodiment, similarly to the initial charging step, the aging step is also performed by the pressure difference between the inside and outside of the battery case 110 without pressing the case main wall portions 110c and 110d with members outside the battery such as the compression tool 200. The inner main surfaces 110c and 110d are pressed against the entire surface of the electrode body main planes 120c and 120d, respectively, and the electrode body 120 is compressed in the thickness direction BH. Therefore, even if gas is generated when the aging process is performed, the gas can be prevented from accumulating between the positive and negative electrode plates 121 and 131. Therefore, the battery 100 with small variations in battery characteristics such as battery capacity and internal resistance can be manufactured. On the other hand, since it is not necessary to use the compression tool 200 in the aging process, the number of the compression tools 200 required for mass production can be reduced, and the equipment for the aging process can be simplified.

また、本実施形態では、減圧封止工程において、圧縮具２００により、電極体主平面１２０ｃ，１２０ｄに掛かる圧力Ｐｏが７５ｋＰａ以上（具体的には８０ｋＰａ）となる力で電池１００を挟むので、電極体１２０が厚み方向ＢＨに十分に圧縮された状態とすることができる。そして、電池ケース１１０の内圧Ｐｂを−７５ｋＰａ以下（具体的には−８０ｋＰａ）として電池ケース１１０を封止するので、封止後の電池１００においても、電池ケース１１０の内外の気圧差（約８０ｋＰａ）が十分に大きくなり、電極体１２０が厚み方向ＢＨに十分に圧縮された状態とすることができる。従って、初期充電工程やエージング工程の際にガスが正負極板１２１，１３１間に溜まるのをより効果的に防止できる。 In the present embodiment, since the battery 100 is sandwiched by the compression tool 200 at a pressure Po applied to the electrode body main planes 120c and 120d of 75 kPa or more (specifically, 80 kPa) in the decompression sealing process, The body 120 can be in a sufficiently compressed state in the thickness direction BH. Since the battery case 110 is sealed with the internal pressure Pb of the battery case 110 being −75 kPa or less (specifically −80 kPa), even in the sealed battery 100, the pressure difference between the inside and outside of the battery case 110 (about 80 kPa). ) Becomes sufficiently large, and the electrode body 120 can be sufficiently compressed in the thickness direction BH. Therefore, it is possible to more effectively prevent gas from accumulating between the positive and negative electrode plates 121 and 131 during the initial charging process and the aging process.

（実施例）
次いで、本発明の効果を検証するために行った試験の結果について説明する。減圧封止工程において、圧縮具２００によって電極体主平面（第１，第２電極体主平面）１２０ｃ，１２０ｄに掛かる圧力Ｐｏを、０〜１５０ｋＰａに変えて製造した複数の電池１００を用意した。具体的には、電極体主平面１２０ｃ，１２０ｄに掛かる圧力Ｐｏを、０ｋＰａ、２５ｋＰａ、５０ｋＰａ、７５ｋＰａ、１００ｋＰａ、１２５ｋＰａまたは１５０ｋＰａとした電池１００をそれぞれ用意した。そして、各々の電池１００について、実施形態と同様に減圧封止工程を行った後、実施形態と同様に充電工程を行った。その際、各電池１００について、初期充電を開始してから初期充電が完了するまでの時間をそれぞれ測定した。その結果を図７に示す。 (Example)
Subsequently, the result of the test conducted in order to verify the effect of this invention is demonstrated. In the reduced pressure sealing step, a plurality of batteries 100 manufactured by changing the pressure Po applied to the electrode body main planes (first and second electrode body main planes) 120c and 120d by the compression tool 200 to 0 to 150 kPa were prepared. Specifically, batteries 100 were prepared in which the pressure Po applied to the electrode body main planes 120c and 120d was 0 kPa, 25 kPa, 50 kPa, 75 kPa, 100 kPa, 125 kPa, or 150 kPa, respectively. And about each battery 100, after performing the pressure reduction sealing process similarly to embodiment, the charging process was performed similarly to embodiment. At that time, for each battery 100, the time from the start of the initial charge to the completion of the initial charge was measured. The result is shown in FIG.

図７のグラフから明らかなように、圧縮具２００により電極体主平面１２０ｃ，１２０ｄに掛かる圧力Ｐｏが０〜７５ｋＰａの範囲では、圧力Ｐｏの値が大きくなるほど、初期充電に要する時間が短くなった。一方、圧縮具２００により電極体主平面１２０ｃ，１２０ｄに掛かる圧力Ｐｏが７５〜１５０ｋＰａの範囲では、圧力Ｐｏの大きさに拘わらず、初期充電に要する時間が短くほぼ一定となった。 As is clear from the graph of FIG. 7, when the pressure Po applied to the electrode body main planes 120c and 120d by the compression tool 200 is in the range of 0 to 75 kPa, the time required for the initial charging is shortened as the value of the pressure Po is increased. . On the other hand, when the pressure Po applied to the electrode body main planes 120c and 120d by the compression tool 200 is in the range of 75 to 150 kPa, the time required for the initial charging is short and substantially constant regardless of the magnitude of the pressure Po.

このような結果を生じた理由は、以下であると考えられる。即ち、電池１００に初期充電を行うと、電解液１１７の一部が分解してガスが発生する。その際、電極体主平面１２０ｃ，１２０ｄに掛かる圧力Ｐｏが０〜７５ｋＰａの範囲では、電極体１２０が厚み方向ＢＨに全く圧縮されていない、或いは十分に圧縮されていないために、圧力Ｐｏの値が小さいほど、発生したガスが電極体１２０から抜けきれずに、正負極板１２１，１３１間に多く溜まる。このガスは、正負極板１２１，１３１間内で移動し離合集散を繰り返すため、正負極板１２１，１３１間には、ガスが接しているために充電できない部分と、電解液１１７に接していて充電できる部分とが現れ、しかも、これらの部分が移動する。このため、圧力Ｐｏの値が小さいほど、正負極板１２１，１３１全体について初期充電するのに時間が長く掛かると考えられる。 The reason for such a result is considered as follows. That is, when the battery 100 is initially charged, a part of the electrolytic solution 117 is decomposed to generate gas. At that time, when the pressure Po applied to the electrode body main planes 120c and 120d is in the range of 0 to 75 kPa, the electrode body 120 is not compressed at all in the thickness direction BH or is not sufficiently compressed. Is smaller, the generated gas is more difficult to escape from the electrode body 120 and accumulates more between the positive and negative electrode plates 121 and 131. Since this gas moves between the positive and negative electrode plates 121 and 131 and repeats separation and scattering, the gas is in contact between the positive and negative electrode plates 121 and 131 and the electrolyte 117 is in contact with the portion that cannot be charged. Parts that can be charged appear, and these parts move. For this reason, it is considered that the smaller the value of the pressure Po, the longer it takes to initially charge the entire positive and negative electrode plates 121 and 131.

一方、電極体主平面１２０ｃ，１２０ｄに掛かる圧力Ｐｏが７５〜１５０ｋＰａの範囲では、電極体１２０が厚み方向ＢＨに十分に圧縮されているため、圧力Ｐｏの大きさに拘わらず、発生したガスの殆ど全てが電極体１２０から抜け出て、正負極板１２１，１３１間には溜まらない。このため、正負極板１２１，１３１は、そのいずれの部位でも電解液１１７に接していて充電できるので、正負極板１２１，１３１全体について初期充電するのに掛かる時間が短くなり、一定時間になると考えられる。 On the other hand, when the pressure Po applied to the electrode body main surfaces 120c and 120d is in the range of 75 to 150 kPa, the electrode body 120 is sufficiently compressed in the thickness direction BH. Almost all escapes from the electrode body 120 and does not collect between the positive and negative electrode plates 121 and 131. For this reason, since the positive and negative electrode plates 121 and 131 can be charged by being in contact with the electrolyte solution 117 at any part thereof, the time required for initial charging of the entire positive and negative electrode plates 121 and 131 is shortened, and when a certain time is reached. Conceivable.

以上より、減圧封止工程を、圧縮具２００で電池１００を挟み、一対の電極体主平面１２０ｃ，１２０ｄの全面をそれぞれ押圧して、電極体１２０を厚み方向ＢＨに圧縮した状態で行うことで、その後の初期充電工程を、圧縮具２００を取り外して行っても、初期充電に要する時間を短くできることが判る。また、圧縮具２００により電極体主平面１２０ｃ，１２０ｄに掛かる圧力Ｐｏを７５ｋＰａ以上とすることで、初期充電に要する時間を最も短くできることが判る。 As described above, the vacuum sealing step is performed in a state where the battery 100 is sandwiched between the compression tools 200 and the entire surfaces of the pair of electrode body main planes 120c and 120d are pressed to compress the electrode body 120 in the thickness direction BH. It can be seen that the time required for the initial charging can be shortened even if the subsequent initial charging step is performed with the compression tool 200 removed. It can also be seen that the time required for the initial charging can be shortened by setting the pressure Po applied to the electrode body main planes 120c, 120d by the compression tool 200 to 75 kPa or more.

以上において、本発明を実施形態に即して説明したが、本発明は上述の実施形態に限定されるものではなく、その要旨を逸脱しない範囲で、適宜変更して適用できることは言うまでもない。
例えば、実施形態では、「電極体」として、各々帯状をなす正極板１２１及び負極板１３１をセパレータ１４１，１４１を介して互いに重ねて扁平状に捲回してなる扁平状捲回型の電極体１２０を例示したが、電極体の形態はこれに限られない。例えば、電極体を、各々所定形状（例えば矩形状など）をなす複数の正極板及び複数の負極板をセパレータを介して交互に複数積層してなる積層型としてもよい。 In the above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof.
For example, in the embodiment, as the “electrode body”, a flat wound electrode body 120 in which a positive electrode plate 121 and a negative electrode plate 131 each having a band shape are overlapped with each other via separators 141 and 141 and wound in a flat shape. However, the form of the electrode body is not limited to this. For example, the electrode body may be a stacked type in which a plurality of positive plates and a plurality of negative plates each having a predetermined shape (for example, a rectangular shape) are alternately stacked via separators.

また、実施形態では、「電池ケース」として、直方体形状の電池ケース１１０を例示したが、電池ケースの形状はこれに限られない。例えば、電池ケースを、一対のケース主壁部を有し、ケース上壁部及びケース下壁部がそれぞれ長円状をなす長円筒形状としてもよい。 In the embodiment, the rectangular battery case 110 is illustrated as the “battery case”, but the shape of the battery case is not limited thereto. For example, the battery case may have a long cylindrical shape having a pair of case main wall portions and the case upper wall portion and the case lower wall portion each having an oval shape.

１００リチウムイオン二次電池（電池）
１１０電池ケース
１１０ａケース上壁部
１１０ｂケース下壁部
１１０ｃ第１ケース側壁部（ケース主壁部）
１１０ｃｎ第１ケース内主面（ケース内主面）
１１０ｄ第２ケース側壁部（ケース主壁部）
１１０ｄｎ第２ケース内主面（ケース内主面）
１１０ｅ第３ケース側壁部
１１０ｆ第４ケース側壁部
１１１ケース本体部材
１１３ケース蓋部材
１２０電極体
１２０ｃ第１電極体主平面（電極体主平面）
１２０ｄ第２電極体主平面（電極体主平面）
１２０ａ第１半円筒面
１２０ｂ第２半円筒面
１５０正極端子
１６０負極端子
２００圧縮具
２１０第１拘束板
２２０第２拘束板
ＢＨ厚み方向
ＣＨ幅方向
ＤＨ高さ方向 100 Lithium ion secondary battery (battery)
110 battery case 110a case upper wall portion 110b case lower wall portion 110c first case side wall portion (case main wall portion)
110cn Main surface inside first case (main surface inside case)
110d Second case side wall (case main wall)
110dn Main surface inside second case (main surface inside case)
110e 3rd case side wall part 110f 4th case side wall part 111 Case main body member 113 Case cover member 120 Electrode body 120c 1st electrode body main plane (electrode body main plane)
120d Second electrode body main plane (electrode body main plane)
120a First semi-cylindrical surface 120b Second semi-cylindrical surface 150 Positive electrode terminal 160 Negative electrode terminal 200 Compressor 210 First constraining plate 220 Second constraining plate BH Thickness direction CH Width direction DH Height direction

Claims

自身の厚み方向に直交する一対の電極体主平面を有する、扁平状捲回型または積層型の電極体と、
前記電極体を収容し、一対の前記電極体主平面にそれぞれ対向する一対のケース内主面を含む一対のケース主壁部を有する電池ケースと、を備える
電池の製造方法であって、
前記電極体が収容された前記電池ケースの内圧を、大気圧Ｐａよりも減圧された内圧Ｐｂとした上で、前記電池ケースを気密に封止する減圧封止工程と、
前記減圧封止工程の後、前記電池について初期充電を行う初期充電工程と、を備え、
前記減圧封止工程は、
電池外の圧縮具で前記電池のうち一対の前記ケース主壁部間を挟んで、一対の前記ケース内主面で一対の前記電極体主平面の全面を押圧して、前記電極体を前記厚み方向に圧縮した状態で行い、
前記初期充電工程は、
電池外の部材で前記ケース主壁部を押圧することなく、前記電池ケースの内外の気圧差により一対の前記ケース内主面で一対の前記電極体主平面の全面を押圧して、前記電極体を前記厚み方向に圧縮した状態で行う
電池の製造方法。 A flat wound-type or laminated-type electrode body having a pair of electrode body main planes orthogonal to its thickness direction;
A battery case having a pair of case main walls including a pair of case main walls that house the electrode body and oppose each of the pair of electrode body main planes,
The internal pressure of the battery case in which the electrode body is accommodated is set to an internal pressure Pb that is reduced from the atmospheric pressure Pa, and then the vacuum sealing step for hermetically sealing the battery case;
An initial charging step for performing initial charging for the battery after the decompression sealing step,
The reduced pressure sealing step includes
A pair of case main wall portions of the battery are sandwiched between the pair of case main walls by a compression tool outside the battery, and the entire surface of the pair of electrode body main planes is pressed by the pair of case main surfaces, so that the electrode body In a compressed state,
The initial charging step includes
Without pressing the case main wall portion with a member outside the battery, the whole of the pair of electrode main surfaces is pressed by the pair of case main surfaces by the pressure difference between the inside and outside of the battery case, and the electrode body The manufacturing method of the battery performed in the state compressed in the said thickness direction.

請求項１に記載の電池の製造方法であって、
前記初期充電工程の後、前記電池についてエージングを行うエージング工程を備え、
前記エージング工程は、
電池外の部材で前記ケース主壁部を押圧することなく、前記電池ケースの内外の気圧差により一対の前記ケース内主面で一対の前記電極体主平面の全面を押圧して、前記電極体を前記厚み方向に圧縮した状態で行う
電池の製造方法。 A battery manufacturing method according to claim 1, comprising:
An aging step for aging the battery after the initial charging step;
The aging process includes
Without pressing the case main wall portion with a member outside the battery, the whole of the pair of electrode main surfaces is pressed by the pair of case main surfaces by the pressure difference between the inside and outside of the battery case, and the electrode body The manufacturing method of the battery performed in the state compressed in the said thickness direction.

請求項１または請求項２に記載の電池の製造方法であって、
前記減圧封止工程は、
前記圧縮具により、前記電極体主平面に掛かる圧力Ｐｏが７５ｋＰａ以上となる力で前記電池を挟み、
前記内圧Ｐｂを、大気圧Ｐａを基準としたゲージ圧表記で−７５ｋＰａ以下とする
電池の製造方法。 A method for producing a battery according to claim 1 or claim 2,
The reduced pressure sealing step includes
The battery sandwiches the battery with a force at which the pressure Po applied to the main surface of the electrode body is 75 kPa or more by the compression tool,
A method for producing a battery, wherein the internal pressure Pb is -75 kPa or less in gauge pressure notation based on atmospheric pressure Pa.