Electricity storage device

Abstract

The invention provides a power storage device. This power storage device is provided with: a case member having a terminal insertion hole; a terminal member that is inserted into the terminal insertion hole; and a resin member made of an insulating resin material, the resin member being hermetically welded to the housing member and the terminal member such that the terminal member is fixed to the housing member so as to be insulated from the housing member, the terminal member having: a belt-shaped first roughened portion having a roughened surface and having an annular shape surrounding the terminal member; and a second roughened portion which is roughened and separated from the first roughened portion, the resin member is integrally insert-molded with the housing member and the terminal member, and the resin member has: a belt-shaped terminal sealing portion which is configured in a ring shape which is fixed to the first roughened portion in an air-tight manner, and a second roughened portion which is roughened and separated from the second roughened portion, and the terminal sealing portion is configured in a ring shape which is fixed to the first roughened portion in an air-tight manner; and a stress reducing part which is fixedly connected to the second roughened part and reduces stress generated in the terminal sealing part.

Description

Technical Field

[0001] The present disclosure relates to an electric storage device. Background Art

[0002] A method is known in which a terminal insertion hole is provided in a cover body of a case member of an electrical storage device, a terminal member is inserted through the terminal insertion hole, and the cover body and the terminal member are fixed integrally and airtightly to each other using an insulating resin member by insert molding (see Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2016-44303

[0004] However, due to the differences in thermal expansion coefficients among the shell component (cover body), terminal component and resin component, stress caused by the thermal expansion difference is generated due to the cooling during the insert molding process. When cooling after molding or during hot and cold cycle tests, the stress may cause cracks in the resin component along the terminal component, thereby damaging the airtightness of the shell, etc., and the reliability related to airtightness may sometimes be reduced. Summary of the invention

[0005] The present disclosure has been made in view of the current situation, and provides an electric storage device having an insulating resin member integrally formed with a case member and a terminal member by insert molding and having improved reliability related to airtightness.

[0006] (1) One method of the present disclosure for solving the above-mentioned problems is an electric storage device comprising: a case member having a terminal insertion hole; a terminal member inserted into the terminal insertion hole; and a resin member, the resin member being made of an insulating resin material and being respectively welded to the case member and the terminal member in an airtight manner so that the terminal member is fixed to the case member in a manner insulated from the case member, wherein the terminal member has a first roughened portion in the shape of a strip, the first roughened portion being roughened and configured as follows: An annular shape surrounding the above-mentioned terminal component; and a second roughened portion, which is roughened and separated from the above-mentioned first roughened portion, the above-mentioned resin component is integrally formed with the above-mentioned shell component and the above-mentioned terminal component insert inserted into the above-mentioned terminal insertion hole, and the above-mentioned resin component has: a strip-shaped terminal sealing portion, which is configured as an annular shape fixed to the above-mentioned first roughened portion of the above-mentioned terminal component in an airtight manner; and a stress reducing portion, which is fixed to the above-mentioned second roughened portion of the above-mentioned terminal component to reduce the stress generated in the above-mentioned terminal sealing portion.

[0007] For this power storage device, stress will remain in the resin part due to the temperature drop after the insert molding. However, in this power storage device, the terminal sealing part of the resin part is fixed to the first roughened part of the terminal part to maintain the airtightness between the first roughened part and the terminal sealing part, and the stress reduction part of the resin part is fixed to the second roughened part of the terminal part, thereby reducing the stress generated in the terminal sealing part of the resin part. Therefore, in this power storage device, the stress generated in the terminal sealing part can be reduced compared to the case where the second roughened part is not provided in the terminal part and the case where the stress reduction part is not provided in the resin part. Therefore, the undesirable situation that cracks are generated in the terminal sealing part and the airtightness of the terminal sealing part is reduced can be suppressed, and the reliability related to airtightness can be improved.

[0008] In addition, as a case where the stress reducing portion is not provided in the resin component, for example, the following case can be cited, that is, regardless of the presence or absence of the second roughened portion in the terminal component, a portion corresponding to the stress reducing portion is not provided in the resin component. In addition, as a case where the second roughened portion is not provided in the terminal component, for example, the following case can be cited, that is, although the resin component has a portion corresponding to the stress reducing portion, the portion corresponding to the stress reducing portion in the resin component cannot be fixed to the portion corresponding to the second roughened portion in the terminal component because a roughened surface corresponding to the second roughened portion is not provided in the terminal component.

[0009] Examples of the power storage device include secondary batteries such as lithium ion secondary batteries and sodium ion secondary batteries, and capacitors such as lithium ion capacitors.

[0010] In addition, the second metal forming the terminal member may be the same as the first metal forming the case member (for example, the same aluminum) or different (for example, aluminum and copper).

[0011] The stress reduction portion of the resin member is fixed to the second roughened portion of the terminal member and may or may not include cracks caused by coagulation failure along the second roughened portion while maintaining fixed contact with the second roughened portion.

[0012] In addition, the second roughened portion of the terminal member may be fixedly connected to the stress reducing portion of the resin member and formed in a range capable of reducing the stress generated in the terminal sealing portion of the resin member, and may be formed in a band shape in a ring shape surrounding the terminal member, or may be formed in a band shape without being formed in a ring shape. The stress reducing portion may also be formed in a band shape in a ring shape fixedly connected to the second roughened portion, or may be formed in a band shape without being formed in a ring shape.

[0013] (2) The power storage device described in (1) above may be a power storage device wherein the stress reduction portion is a crack-including portion that is fixed to the second roughened portion of the terminal member and includes cracks caused by coagulation failure along the second roughened portion.

[0014] In this power storage device, the stress reduction portion becomes a crack-containing portion that contains cracks. That is, it is considered that since the stress generated in the stress reduction portion exceeds the strength of the resin material, cracks caused by condensation failure are generated in the stress reduction portion. However, the stress generated in the stress reduction portion due to the generation of the cracks is released, and the stress generated in the terminal sealing portion is also reduced, thereby achieving a more stable state.

[0015] (3) The energy storage device described in (1) or (2) above may be an energy storage device as follows, namely: a forest of nanocolumns is arranged in the above-mentioned first roughened portion of the above-mentioned terminal component, the nanocolumns are formed by particles from the above-mentioned terminal component being connected in a bead-like manner to form a columnar shape, and the height of the nanocolumns is greater than 50 nm, and the above-mentioned terminal sealing portion of the above-mentioned resin component is fixed to the above-mentioned first roughened portion in an airtight manner by filling the above-mentioned resin material between the forest of nanocolumns.

[0016] In the power storage device, the first roughened portion of the terminal component becomes a roughened surface with a forest of nanopillars. On the other hand, since the resin material forming the terminal sealing portion of the resin component is filled between the nanopillars, the first roughened portion and the terminal sealing portion can be firmly fixed and the airtightness between the two can be well maintained.

[0017] (4) The energy storage device described in any one of (1) to (3) above may be an energy storage device as follows, namely: a forest of nanocolumns is arranged in the second roughened portion of the terminal component, the nanocolumns are formed by particles from the terminal component being connected in a bead-like manner to form a columnar shape, and the height of the nanocolumns is greater than 50 nm, and the stress reduction portion of the resin component is fixed to the second roughened portion by filling the resin material between the forested nanocolumns.

[0018] In this power storage device, the second roughened portion of the terminal member is formed as a roughened surface with nanopillars. Meanwhile, since the resin material forming the stress reduction portion of the resin member is filled between the nanopillars, the second roughened portion and the stress reduction portion can be firmly fixed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a perspective view of batteries according to the embodiment, comparative embodiment, and modified embodiment.

[0020] Figure 2It is a longitudinal cross-sectional view along the battery height direction and the battery width direction of the battery according to the embodiment, the comparative embodiment, and the modified embodiment.

[0021] Figure 3 This is a partial enlarged cross-sectional view showing an enlarged view of the terminal insertion hole and the vicinity of the cover member in the battery according to the embodiment.

[0022] Figure 4 The embodiments, comparative embodiments, and modified embodiments are partially enlarged cross-sectional views showing nanocolumns standing in a roughened portion of a terminal member and a cover member and a resin member filled therein.

[0023] Figure 5 This is a flowchart of a method for manufacturing a battery according to an embodiment.

[0024] Figure 6 It is an exploded view of batteries according to the embodiment, comparative embodiment, and modified embodiment.

[0025] Figure 7 The diagram is an explanatory diagram of a method for manufacturing a battery according to an embodiment, showing how a plurality of bowl-shaped recesses and nanocolumns arranged in the bowl-shaped recesses are formed by scanning with a pulsed laser in a sealing portion forming step.

[0026] Figure 8 The battery according to the modified embodiment is a partial enlarged cross-sectional view showing the vicinity of the terminal insertion hole of the cover member, the terminal member, and the resin member in an enlarged manner.

[0027] Fig. 9 The battery involved in the deformation mode is Figure 8 The D-D section view in the figure.

[0028] Fig.10 It is a partial enlarged cross-sectional view showing the vicinity of the terminal insertion hole of the cover member, the terminal member, and the resin member in the battery according to the comparative embodiment.

[0029] Description of reference numerals:

[0030] 1, 101, C1…battery (electrical storage device); 10…housing; 20…housing body member (housing member); 30…cover member (housing member); 30h…terminal insertion hole; 30hs…inner peripheral surface (of terminal insertion hole); 31…peripheral portion; 31s1…cover seal outer side roughening portion (of cover member); 31s2…cover seal inner side roughening portion (of cover member); 40…electrode body; 50, 150…terminal member; 50a…top plate portion; 50b…bent extension portion; 50c, 150c…step extension portion; 50ca…inner end surface; 50cb…outer end surface; 150car…inner end R surface; 150cbr…outer end R surface; 50 d…connecting portion; 51…first roughened portion; 51a…inner end surface roughened portion; 51b…outer end surface roughened portion; 51c, 51d…flat surface roughened portion; 52a, 52b…end surface roughened portion (second roughened portion); 152a, 152b…end R surface roughened portion (second roughened portion); 70, 170…resin component; 70R…resin material; 71…top plate peripheral portion; 72…peripheral outer portion; 73…peripheral inner portion; 74…through hole filling portion (terminal sealing portion); 75…step surrounding portion (stress reduction portion, crack containing portion); 175…step surrounding portion (stress reduction portion); CL1, CL2…crack; LC…pulsed laser. DETAILED DESCRIPTION

[0031] (Implementation Method)

[0032] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Figure 1 A perspective view showing a battery (electricity storage device) 1 according to the present embodiment, Figure 2 1 is a longitudinal cross-sectional view of the battery 1. Figure 3 FIG. 1 is a partial enlarged cross-sectional view showing the vicinity of the terminal insertion hole 30h of the cover member 30 in the cover assembly 15 in the battery 1. In addition, hereinafter, the battery height direction AH, the battery width direction BH, and the battery thickness direction CH of the battery 1 are defined as Figure 1 and Figure 2 The directions shown are used for illustration.

[0033] The battery 1 is a sealed lithium-ion secondary battery in a square (rectangular) shape mounted on a hybrid vehicle, a plug-in hybrid vehicle, an electric vehicle, or the like. The battery 1 is composed of a housing 10, an electrode body 40 housed in the housing 10, and positive and negative terminal components 50 fixed to the housing 10 via a resin component 70, etc. The electrode body 40 is covered by a bag-shaped insulating retainer 7 composed of an insulating film in the housing 10. In addition, an electrolyte 5 is contained in the housing 10, a part of which is immersed in the electrode body 40, and the remaining part is stored in the inner bottom of the housing 10.

[0034] The shell 10 is a rectangular box made of metal (aluminum in this embodiment), and is a square tube with a bottom having a rectangular opening 20c. It is composed of a shell body part 20 that accommodates the electrode body 40 inside, and a rectangular plate-shaped cover part 30 that closes the opening 20c of the shell body part 20. The opening 20c of the shell body part 20 and the peripheral part 30f of the cover part 30 are welded in an airtight manner throughout the entire circumference. A safety valve 11 is provided on the cover part 30, which breaks and opens the valve when the internal pressure of the shell 10 exceeds the valve opening pressure. In addition, a liquid injection hole 30k is provided on the cover part 30, and the liquid injection hole 30k is sealed in an airtight manner by a circular plate-shaped liquid injection plug 12 made of aluminum.

[0035] The electrode body 40 is a flat cylindrical, wound-type electrode body, which is formed by alternately stacking and winding two long strips of positive electrode plates 41 and negative electrode plates 42 through a porous resin separator 43, and then compressing them into a flat shape in the battery thickness direction CH. One side BH1 ( Figure 2 The positive electrode current collecting portion 40p is formed by overlapping the current collecting foil of the positive electrode plate 41 in a spiral shape. The positive electrode current collecting portion 40p is welded to the terminal member 50 of the positive electrode to be conductive. In addition, on the other side BH2 ( Figure 2 As shown in the figure, on the right side in FIG. 1 , a negative electrode current collecting portion 40n is formed by overlapping the current collecting foils of the negative electrode plates 42 in a spiral shape. The negative electrode current collecting portion 40n is welded to the terminal member 50 of the negative electrode to be conductive.

[0036] Rectangular terminal insertion holes 30h are provided near both ends of one side BH1 and the other side BH2 in the battery width direction BH of the cover member 30. A positive terminal member 50 made of aluminum is inserted into the terminal insertion holes 30h on the one side BH1, and the terminal member 50 is fixed to the cover member 30 in an airtight manner while being insulated from the cover member 30 via a resin member 70 welded thereto. On the other hand, a negative terminal member 50 made of copper is inserted into the terminal insertion holes 30h on the other side BH2, and the terminal member 50 is fixed to the cover member 30 in an airtight manner while being insulated from the cover member 30 via a resin member 70 welded thereto.

[0037] according to Figure 1 , Figure 2 It can be easily understood that the positive and negative terminal components 50 have substantially mirror-image shapes and are formed by punching and cutting and bending metal plates (aluminum plate for the positive electrode and copper plate for the negative electrode).

[0038] The terminal member 50 includes: a rectangular flat plate-shaped top plate portion 50a, which is located at an upper side AH1 in the battery height direction AH than the cover member 30 and extends in the battery width direction BH and the battery thickness direction CH; and a bent extension portion 50b, which extends from one side CH1 (CH) of the top plate portion 50a in the battery thickness direction CH. Figure 2 , Figure 3 The edge of the terminal member 50 is bent at a right angle and extends to the lower side AH2 in the battery height direction AH. In addition, the terminal member 50 has a stepped extension portion 50c, which extends from the bent extension portion 50b to the outer side BHO in the battery width direction BH (one side BH1 in the positive terminal member 50, the other side BH2 in the negative terminal member 50, see Figure 2 ) position is offset and extends to the lower side AH2 in the battery height direction AH; and a connecting portion 50d, which extends from the stepped extension portion 50c to the lower side AH2 in the battery height direction AH, and halfway to the other side CH2 in the battery thickness direction CH ( Figure 2 The bent extension portion 50b, the stepped extension portion 50c and the connecting portion 50d are all rectangular in cross section perpendicular to the battery height direction AH and are long in the battery width direction BH.

[0039] The bent extension 50b of the terminal member 50 is inserted into the terminal insertion hole 30h of the cover member 30. In addition, the connection portion 50d of the positive terminal member 50 is welded to the positive current collecting portion 40p of the electrode body 40, thereby the positive potential of the positive current collecting portion 40p is pulled out to the top plate portion 50a of the positive terminal member 50. Similarly, the connection portion 50d of the negative terminal member 50 is also welded to the negative current collecting portion 40n of the electrode body 40, thereby the negative potential of the negative current collecting portion 40n is pulled out to the top plate portion 50a of the negative terminal member 50.

[0040] The terminal parts 50 of the positive and negative electrodes are fixedly connected to the cover part 30 as a whole by the resin part 70 formed by insert molding. The resin part 70 of this embodiment is composed of a resin material 70R containing a thermoplastic main resin (specifically polyphenylene sulfide (PPS)), a thermoplastic elastomer and a filler (specifically a fibrous glass filler). The resin part 70 is roughly divided into a top plate peripheral part 71, a peripheral outer part 72, a peripheral inner part 73, a through hole filling part 74 as a terminal sealing part, and a stepped surrounding part 75 as a stress reduction part. Among them, the top plate peripheral part 71 is a rectangular annular part located outside the plane direction of the top plate part 50a of the terminal part 50, that is, around the battery width direction BH and the battery thickness direction CH. The peripheral outer part 72 is an annular part located on the lower side AH2 of the top plate peripheral part 71 and on the upper side AH1 of the annular peripheral part 31 surrounding the terminal insertion hole 30h in the cover part 30. The peripheral inner portion 73 is an annular portion located at the lower side AH2 of the peripheral portion 31 of the cover member 30. In addition, the insertion hole filling portion 74 is an annular portion located at the lower side AH2 of the top plate peripheral portion 71 and is sandwiched between the inner peripheral surface 30hs of the terminal insertion hole 30h of the cover member 30 and the curved extension portion 50b of the terminal member 50. Furthermore, the stepped surrounding portion 75 is an annular portion that surrounds the stepped extension portion 50c of the terminal member 50 at the lower side AH2 of the insertion hole filling portion 74 and the lower side AH2 of the cover member 30.

[0041] First, the connection and airtightness between the cover member 30 and the resin member 70 in the battery 1 will be described. In the annular peripheral portion 31 surrounding the terminal insertion hole 30h of the cover member 30, the outer side surface 30s1 facing the upper side AH1 is formed. Figure 3 As shown in the thick line, a band-shaped cover seal outer roughened portion 31s1 is formed in a ring shape surrounding the terminal insertion hole 30h. In addition, an inner side surface 30s2 facing the lower side AH2 in the peripheral portion 31 is formed. Figure 3 As shown by the thick line in the middle, a belt-shaped cover seal inner roughened portion 31s2 is formed in a ring shape surrounding the terminal insertion hole 30h. The cover seal outer roughened portion 31s1 and the cover seal inner roughened portion 31s2 are roughened surfaces roughened by roughening treatment using pulsed laser LC described later. That is, a plurality of nanopillars 36 are arranged in the cover seal outer roughened portion 31s1 and the cover seal inner roughened portion 31s2, as shown in FIG. Figure 4 As shown, the nanocolumn 36 is a columnar structure formed by connecting particles 36p from the metal (aluminum in this embodiment) forming the cover member 30 in a bead-like manner, and has a height ha of 50 nm or more (approximately ha=150 nm in this embodiment).

[0042] In addition, the cover seal outer roughened portion 31s1 and the cover seal inner roughened portion 31s2 are filled with the resin material 70R that forms the peripheral outer portion 72 and the peripheral inner portion 73 of the resin member 70. Therefore, the cover seal outer roughened portion 31s1 and the peripheral outer portion 72, and the cover seal inner roughened portion 31s2 and the peripheral inner portion 73 have a long surface distance in the width direction of the cover seal outer roughened portion 31s1 or the cover seal inner roughened portion 31s2 (radial direction of the terminal insertion hole 30h), respectively, so that they are firmly fixed. Therefore, the resin member 70 is firmly fixed to the peripheral portion 31 of the cover member 30, and the interface between the peripheral portion 31 of the cover member 30 and the resin member 70 is sealed with high airtightness by the annular cover seal outer roughened portion 31s1 and the cover seal inner roughened portion 31s2. Furthermore, in the battery 1 of this embodiment, since two roughened portions, namely the cover seal outer roughened portion 31s1 and the cover seal inner roughened portion 31s2, are provided on the peripheral portion 31 of the cover member 30, particularly high reliability can be obtained in terms of airtightness between the cover member 30 and the resin member 70.

[0043] Next, the bonding and airtightness between the positive and negative terminal members 50 and the resin member 70 in the battery 1 will be described. Figure 3 As shown in the dot pattern and the bold line, the portion of the bent extension 50b that is located near the terminal insertion hole 30h and is in the shape of a band surrounding the terminal member 50 is the first roughened portion 51. The first roughened portion 51 is roughly composed of an inner end surface roughened portion 51a facing the inner side BHI in the battery width direction BH, an outer end surface roughened portion 51b facing the outer side BHO in the battery width direction BH, and a side CH1 ( Figure 3 inside) and the other side CH2 ( Figure 3 The first roughened portion 51 is a rectangular ring-shaped band-shaped roughened surface composed of four surfaces, namely, the flat roughened portions 51c and 51d on the near front side of the image. The first roughened portion 51 is also a roughened surface obtained by roughening using the pulsed laser LC described later. That is, the first roughened portion 51 is also lined with nanopillars 56, such as Figure 4 As shown, the nanocolumn 56 is a columnar structure formed by particles 56p of the metal forming the terminal component 50 (in the present embodiment, the positive terminal component is aluminum and the negative terminal component is copper) connected in a bead-like manner, and its height ha is greater than 50 nm (in the present embodiment, the approximate height is ha = 150 nm).

[0044] Furthermore, the first roughened portion 51 is also filled with a resin material 70R forming an insertion hole filling portion 74 of the resin member 70 as described later. The insertion hole filling portion 74 of the resin member 70 has a width direction ( Figure 3 A longer creeping distance in the battery height direction AH) is achieved, thereby being firmly fixed to the first roughened portion 51.

[0045] Therefore, the interface between the bent extension portion 50b of the terminal component 50 and the insertion hole filling portion 74 of the resin component 70, and further the interface between the terminal component 50 and the resin component 70, can maintain particularly good airtightness between the band-shaped annular first roughened portion 51 and the insertion hole filling portion 74.

[0046] Furthermore, in the present embodiment, the end surface roughened portions 52a and 52b are formed as the second roughened portion at a portion of the stepped extension portion 50c of the positive and negative terminal members 50. Specifically, Figure 3 As shown by the thick line in the middle, the upper side AH1 in the battery height direction AH of the step extension 50c, the end surface roughening portion 52a facing the inner side BHI in the battery width direction BH, and the end surface roughening portion 52b facing the outer side BHO in the battery width direction BH also become roughened surfaces obtained by roughening treatment using the pulse laser LC described later. That is, the end surface roughening portions 52a and 52b also have a forest of nanopillars 56, as shown in FIG. Figure 4 As shown, the nanocolumn 56 is a columnar structure formed by connecting particles 56p of the metal (aluminum or copper in this embodiment) forming the terminal member 50 in a beaded manner, and has a height ha of more than 50 nm (approximately ha=150 nm in this embodiment).

[0047] As will be described later, the end surface roughened portions 52a and 52b of the stepped extension portion 50c are also filled with the resin material 70R that forms the resin member 70. Therefore, the step surrounding portion 75 of the resin member 70 surrounds the stepped extension portion 50c of the terminal member 50 and is firmly fixed to the end surface roughened portions 52a and 52b at least two locations in the stepped extension portion 50c.

[0048] Furthermore, by injection molding the resin material 70R as described later, the cover member 30 and a pair of terminal members 50 inserted into the terminal insertion holes 30h are fixed as a whole by the resin member 70 to form the cover assembly 15. However, since there is a difference in thermal expansion coefficient between the metal (aluminum and copper in this embodiment) forming the cover member 30 and the terminal member 50 and the resin material 70R, thermal stress caused by the thermal expansion difference is generated in each component that has been cooled after molding.

[0049] Here, if Fig.10 As shown, a comparison battery C1 which is identical to the battery 1 of the present embodiment but differs in that the end surface roughening portions 52a, 52b are not provided in the stepped extension 50c of the terminal part 50 is compared with the battery 1 of the present embodiment, and the stress generated in each part of the resin part 70 is explained.

[0050] In the battery C1 of the comparative embodiment, when the battery C1 is exposed to a temperature environment of about room temperature or to an environment of a temperature lower than room temperature (e.g., -40°C) during a thermal cycle test, relatively high stress is generated near the first roughened portion 51 of the insertion hole filling portion 74 in the resin member 70. Among them, a high stress is generated near the outer end surface roughened portion 51b of the first roughened portion 51 in the insertion hole filling portion 74. In addition, the stress generated near the inner end surface roughened portion 51a of the insertion hole filling portion 74 is higher than the stress generated near the outer end surface roughened portion 51b, so that the highest stress is generated in the resin member 70.

[0051] Therefore, when the battery C1 is exposed to an environment at room temperature or lower, Fig.10 As shown, cracks CL1 caused by coagulation failure may sometimes occur along the inner end surface roughening portion 51a in the insertion hole filling portion 74 of the resin component 70. In addition, cracks caused by coagulation failure may also occur near the outer end surface roughening portion 51b (not shown). This is considered to be because the stress generated in these parts exceeds the strength of the resin material 70R. For the battery C1 in which the cracks CL1 are generated in the insertion hole filling portion 74 of the resin component 70, the airtightness of the interface between the terminal component 50 and the resin component 70 is greatly reduced. In this way, it can be seen that regardless of whether the cracks CL1 are generated, the reliability of the battery C1 in terms of airtightness of the comparison method is low.

[0052] In contrast, when the battery 1 of the present embodiment is exposed to an environment at room temperature or lower, the stress generated near the outer end surface roughening portion 51b and the inner end surface roughening portion 51a of the first roughening portion 51 in the insertion hole filling portion 74 of the resin component 70 is significantly reduced (for example, to less than 1 / 2 in the present embodiment) compared to the battery C1.

[0053] However, instead of this, a stress higher than the stress near the outer end surface roughened portion 51b of the first roughened portion 51 is generated near the end surface roughened portion 52b of the outer side BHO of the step surrounding portion 75 in the resin member 70. Furthermore, the stress generated near the end surface roughened portion 52a of the inner side BHI is higher than the stress generated near the inner end surface roughened portion 51a of the first roughened portion 51, and is the highest stress in the resin member 70.

[0054] In the battery 1 of the present embodiment, as described above, the terminal member 50 is provided with not only the first roughened portion 51 fixed to the insertion hole filling portion 74, but also the end surface roughened portions 52a and 52b fixed to the step surrounding portion 75 which is located on the outside (located on the lower side AH2 in the present embodiment) and has a relatively large volume when viewed from the insertion hole filling portion 74. Therefore, most of the stress generated in the resin member 70 due to the thermal expansion difference caused by the cooling of the battery 1 is applied to the portion near the end surface roughened portions 52a and 52b in the step surrounding portion 75. And, accompanying this, it is considered that the stress generated near the outer end surface roughened portion 51b and the inner end surface roughened portion 51a of the first roughened portion 51 in the insertion hole filling portion 74 is reduced compared with the battery C1.

[0055] That is, in this embodiment, the stepped surrounding portion 75 of the resin component 70 is partially fixed to the end face roughening portions 52a, 52b of the terminal component 50, thereby reducing the stress generated in the insertion hole filling portion 74, especially the stress generated near the outer end face roughening portion 51b and the inner end face roughening portion 51a.

[0056] Furthermore, in the battery 1 of the present embodiment, unlike the battery C1, it is possible to prevent the generation of cracks CL1 near the inner end surface roughening portion 51a or near the inner end surface roughening portion 51a and the outer end surface roughening portion 51b in the insertion hole filling portion 74 of the resin member 70 (see Fig.10 ).

[0057] Thus, in the battery 1, the maximum stress generated in the insertion hole filling portion 74 can be reduced compared to the case where the stepped surrounding portion 75 as the stress reduction portion is not provided in the resin member 70 and the end surface roughened portions 52a and 52b are not provided in the terminal member 50. Therefore, the occurrence of cracks in the insertion hole filling portion 74, which causes a decrease in airtightness at the interface between the terminal member 50 and the resin member 70 as in the comparative battery C1, can be suppressed, and the reliability of the battery 1 related to airtightness is improved.

[0058] In addition, if Figure 3As shown, the stress generated in the stepped surrounding portion 75 becomes the highest in the resin component 70 near the end surface roughening portion 52a, and sometimes cracks CL2 caused by condensation damage are generated along the end surface roughening portion 52a. In addition, cracks caused by condensation damage may also be generated near the outer end surface roughening portion 52b and along the end surface roughening portion 52b (not shown). It is believed that this is because the stress generated in these parts exceeds the strength of the resin material 70R. However, unlike the above-mentioned crack CL1, the crack CL2 has no effect on the sealing performed by the insertion hole filling portion 74, and will not reduce the airtightness at the interface between the terminal component 50 and the resin component 70.

[0059] Furthermore, in the crack-containing portion including the crack CL2, that is, the step surrounding portion 75, the stress generated in the step surrounding portion 75 before the crack is generated is released by the generation of the crack CL2, and the stress generated in the insertion hole filling portion 74 is also reduced, thereby achieving a more stable state.

[0060] Next, a method for manufacturing the battery 1 of this embodiment will be described (see Figures 5 to 8 ). First, prepare the cover member 30 before roughening. The cover member 30 before roughening is obtained by stamping using an aluminum plate. In addition, prepare the terminal member 50 before roughening. The terminal member 50 before roughening is obtained by stamping using a metal plate (a positive electrode is an aluminum plate, and a negative electrode is a copper plate).

[0061] Then, in the terminal roughening step S1, the pulse laser LC is intermittently irradiated to the bent extension 50b of the terminal member 50 while shifting the irradiation position, so that a plurality of bowl-shaped recesses 55 are arranged in a partially overlapping band shape to form a ring-shaped first roughening portion 51 (see Figure 3 , Figure 7 ). In addition, in the upper side AH1 of the inner end face 50ca and the outer end face 50cb of the stepped extension 50c of the terminal member 50, the pulse laser LC is intermittently irradiated while shifting the irradiation position, thereby forming end face roughening portions 52a and 52b in which a plurality of bowl-shaped recesses 55 are arranged to overlap partially (see Figure 3 , Figure 7 ).

[0062] Furthermore, in another cover roughening step S2, the outer side surface 30s1 and the inner side surface 30s2 of the peripheral portion 31 of the terminal insertion hole 30h of the cover member 30 are intermittently irradiated with the pulse laser LC while shifting the irradiation position, thereby forming annular cover seal outer side roughening portions 31s1 and cover seal inner side roughening portions 31s2 in the form of a band in which a plurality of bowl-shaped recesses 35 are arranged to overlap partially (see FIG. Figure 3 , Figure 7 ) The irradiation conditions of the pulse laser LC are the same as the irradiation conditions when the laser is irradiated to the positive electrode terminal member 50 in the terminal roughening step S1.

[0063] Next, in the insert molding step S3, the cover assembly 15 (see FIG. 1 ) is formed by insert molding, in which the cover member 30 and the pair of terminal members 50 are fixed as one body via the resin member 70. Figure 6 Specifically, in a metal mold (not shown), a state is formed in which a pair of terminal insertion holes 30h of the cover member 30 are respectively inserted with positive and negative terminal members 50, and a molten resin material 70R is injected to be melted to the peripheral portion 31 of the cover member 30 and a portion of the top plate portion 50a, the curved extension portion 50b and the stepped extension portion 50c of the terminal member 50 and cooled, thereby insert molding a pair of resin members 70. At this time, the molten resin material 70R is respectively filled between the nanopillars 36 of the cover seal outer roughened portion 31s1 and the cover seal inner roughened portion 31s2 of the cover member 30, and between the nanopillars 56 of the first roughened portion 51 and the end surface roughened portions 52a, 52b of the terminal member 50, so that they can be firmly fixed.

[0064] Next, in the electrode body connecting step S4, the connecting portion 50d (see FIG. 1 ) of the positive electrode terminal member 50 in the cap assembly 15 is welded to the positive electrode current collecting portion 40p of the electrode body 40 prepared in advance. Figure 1 , Figure 2 , Figure 6 ). In addition, the connection portion 50d of the negative electrode terminal member 50 in the cap assembly 15 is welded to the negative electrode current collecting portion 40n of the electrode body 40. Thereafter, the electrode body 40 is covered with a bag-shaped insulating holder 7.

[0065] Next, in the electrode body housing and case forming step S5, the electrode body 40 covered by the insulating holder 7 is inserted into the case body member 20, and the opening 20c of the case body member 20 is closed by the cover member 30. Then, the opening 20c of the case body member 20 and the peripheral portion 30f of the cover member 30 are laser welded in an airtight manner throughout the entire circumference, thereby forming the case 10 in which the electrode body 40 is housed.

[0066] Next, in the injection and sealing step S6, the electrolyte 5 is injected into the case 10 through the injection hole 30k to allow the electrolyte 5 to penetrate into the electrode body 40. Thereafter, the injection hole 30k is covered from the outside with the injection plug 12, and the injection plug 12 is laser welded to the case 10 in an airtight manner.

[0067] Next, in the initial charging and aging step S7, a charging device (not shown) is connected to the battery 1 to perform initial charging on the battery 1. Thereafter, the initially charged battery 1 is left at a high temperature (e.g., 60° C.) for a predetermined time to age the battery 1. In this way, the battery 1 is completed.

[0068] In the manufacture of the comparative battery C1, the same process as the battery 1 is used. However, in the terminal roughening process S1, the end surface roughening portions 52a and 52b are not formed on the inner end surface 50ca and the outer end surface 50cb of the stepped extension portion 50c of the terminal member 50, and only the first roughening portion 51 in the form of a ring is formed in the form of a band on the bent extension portion 50b (see FIG. Fig.10 ).

[0069] (Deformation method)

[0070] Next, a battery 101 according to a modified embodiment will be described with reference to the accompanying drawings. The battery 101 according to this modified embodiment is different from the battery 1 according to the above-mentioned embodiment in the cross-sectional shape of the stepped extension 150c of the terminal member 150 and the manner in which the roughened portion provided on the stepped extension 150c is formed (see FIG. Figure 8 , Fig. 9 ), and the other aspects are the same. Therefore, the description will be centered on the different parts, the same parts will be marked with the same figure numbers, and the description will be omitted or simplified except for the above.

[0071] The terminal member 150 used in the battery 101 has a substantially similar shape to the terminal member 50 of the battery 1. However, as described above, the stepped extension 50c of the terminal member 50 has a rectangular cross-sectional shape, and end surface roughening portions 52a and 52b are formed on the inner end surface 50ca facing the inner side BHI and the outer end surface 50cb facing the outer side BHO, respectively, on the upper side AH1.

[0072] In contrast, Fig. 9 As shown, the cross-sectional shape of the stepped extension portion 150c of the terminal component 150 is a rounded rectangular shape. That is, in addition to the flat surfaces 150cc and 150cd extending in the battery width direction BH, the corners are R-chamfered and integrated with the end surface, and have an inner end R surface 150car facing the inner side BHI and an outer end R surface 150cbr facing the outer side BHO. Moreover, in the upper side AH1 portion of the inner end R surface 150car and the outer end R surface 150cbr of the stepped extension portion 150c, end R-surface roughened portions 152a and 152b are respectively formed as the second roughened portion. In addition, similar to the end surface roughened portions 52a and 52b of the battery 1, the end R-surface roughened portions 152a and 152b of the battery 101 are also lined with nanocolumns 56, as shown in FIG. Figure 4As shown, the nanocolumn 56 is a columnar structure formed by particles 56p of a metal (aluminum or copper in this embodiment) forming the terminal member 150 connected in a bead-like manner, and its height ha is greater than 50 nm (approximately ha=150 nm in this embodiment).

[0073] In addition, the end R surface roughened portions 152a and 152b of the stepped extension portion 150c are also filled with the resin material 70R that forms the resin member 70. Therefore, the step surrounding portion 75 of the resin member 70 surrounds the stepped extension portion 150c of the terminal member 150 and is firmly fixed to the end R surface roughened portions 152a and 152b at least two locations in the stepped extension portion 150c.

[0074] Therefore, similar to the battery 1 of the embodiment, when the battery 101 of the modified embodiment is exposed to an environment at room temperature or lower, the stress generated near the outer end surface roughening portion 51b and the inner end surface roughening portion 51a of the first roughening portion 51 in the insertion hole filling portion 74 of the resin component 70 is greatly reduced (for example, to less than 1 / 2 in this modified embodiment) compared to the battery C1.

[0075] On the other hand, in the vicinity of the end R-surface roughened portion 152b on the outside of the step surrounding portion 75 in the resin member 70, a stress higher than the stress near the outer end surface roughened portion 51b of the first roughened portion 51 is generated. In addition, the stress generated near the end R-surface roughened portion 152a on the inside is higher than the stress generated near the inner end surface roughened portion 51a of the first roughened portion 51, and is the highest stress in the resin member 70.

[0076] Therefore, for the battery 101 of the deformed form, the maximum stress generated in the insertion hole filling portion 74 can be reduced compared to the case where the stepped surrounding portion 75 is not provided in the resin member 70 and the end R surface roughened portions 152a and 152b are not provided in the terminal member 150. Therefore, the occurrence of cracks in the insertion hole filling portion 74 and the deterioration of the airtightness at the interface between the terminal member 50 and the resin member 70 can be suppressed, and the reliability of the battery 101 related to the airtightness is improved.

[0077] In addition, if the battery 1 of the embodiment is compared with the battery 101 of the deformation mode, the stress generated near the end surface roughening parts 52a and 52b in the step surrounding part 75 in the battery 1 is relatively low. The reason is considered to be as follows. That is, as described above, in the battery 1, since the cross-section of the step extension part 50c of the terminal member 50 is made rectangular, stress is concentrated near the corner and high stress is easily generated. In contrast, in the battery 101 of the present deformation mode, the cross-sectional shape of the step extension part 150c of the terminal member 150 is made into a rounded rectangular shape as described above. Therefore, it is considered that stress concentration will not be generated near the corner, and the stress generated near the end surface roughening parts 152a and 152b in the step surrounding part 75 is relatively low.

[0078] As described above, in the battery 1, if Figure 3 As shown, cracks CL2 due to coagulation failure may occur along the end surface roughened portion 52a in the step surrounding portion 75. In addition, cracks may also occur along the outer end surface roughened portion 52b.

[0079] In contrast, in the battery 101, Figure 8 There is no record of crack CL2 in the battery 1, which shows that cracks are less likely to occur in the step surrounding portion 75 compared to the battery 1. As described above, this is considered to be because the stress generated in the step surrounding portion 75 is relatively low and is less likely to exceed the strength of the resin material 70R. Therefore, in the battery 101, batteries whose stress is released due to the generation of crack CL2 and batteries whose stress is not released are less likely to coexist, so that a battery 101 with stable quality can be obtained.

[0080] As mentioned above, although the present invention has been described by means of the embodiment and the modified form, the present invention is not limited to the embodiment and the like, and can of course be applied with appropriate changes without departing from the gist of the present invention.

[0081] For example, in the embodiment, the following example is shown, namely: the inner end face 50ca and the outer end face 50cb in the stepped extension 50c of the terminal part 50 are respectively provided with end face roughening portions 52a and 52b, but the flat surfaces 50cc and 50cd facing the battery thickness direction CH are not provided with roughening portions.

[0082] However, similarly to the first roughened portion 51, the stepped extended portion 50c may include the end surface roughened portions 52a and 52b, and the annular second roughened portion may be provided in a band shape surrounding the stepped extended portion 50c.

[0083] In addition, the cover seal outer roughened portion 31s1, the first roughened portion 51, the end surface roughened portions 52a, 52b, etc., are formed with roughened surfaces having a forest of nanorods 36, 56 by irradiation with the pulsed laser LC. However, other roughening treatment methods may also be used. For example, the roughened surface may be formed by physical roughening treatment such as shot peening, grinding, and spraying, or chemical roughening treatment such as anodizing.

Claims

1. An electric storage device comprising: a housing member having a terminal insertion hole; a terminal member inserted into the terminal insertion hole; and a resin component, the resin component being made of an insulating resin material and being respectively welded to the housing component and the terminal component in an airtight manner so that the terminal component is fixed to the housing component in an insulated manner from the housing component, The power storage device is characterized in that The terminal component has: a first roughened portion in a band shape, the first roughened portion being roughened and configured in a ring shape surrounding the terminal member; and a second roughened portion, the second roughened portion being roughened and separated from the first roughened portion, The resin component is integrally formed with the housing component and the terminal component insert inserted into the terminal insertion hole. The resin component has: a band-shaped terminal sealing portion configured in a ring shape and airtightly fixed to the first roughened portion of the terminal member; and A stress reducing portion is fixed to the second roughened portion of the terminal member and reduces stress generated in the terminal sealing portion.

2. The power storage device according to claim 1, characterized in that The stress reduction portion is a crack-including portion that is fixed to the second roughened portion of the terminal member and includes a crack caused by coagulation failure along the second roughened portion.

3. The power storage device according to claim 1 or 2, characterized in that: The first roughened portion of the terminal member is lined with nanocolumns, the nanocolumns being formed into a columnar shape by particles from the terminal member being connected in a bead-like manner and having a height of 50 nm or more. The terminal sealing portion of the resin member is fixed to the first roughened portion in an airtight manner by filling the resin material between the nano-columns standing in a forest.

4. The power storage device according to claim 1, characterized in that The second roughened portion of the terminal member is lined with nanocolumns, the nanocolumns being formed into a columnar shape by particles from the terminal member being connected in a bead-like manner and having a height of 50 nm or more. The stress reduction portion of the resin member is fixed to the second roughened portion by filling the resin material between the forested nano-columns.

5. The power storage device according to claim 2, characterized in that: The second roughened portion of the terminal member is lined with nanocolumns, the nanocolumns being formed into a columnar shape by particles from the terminal member being connected in a bead-like manner and having a height of 50 nm or more. The stress reduction portion of the resin member is fixed to the second roughened portion by filling the resin material between the forested nano-columns.

6. The power storage device according to claim 3, characterized in that The second roughened portion of the terminal member is lined with nanocolumns, the nanocolumns being formed into a columnar shape by particles from the terminal member being connected in a bead-like manner and having a height of 50 nm or more. The stress reduction portion of the resin member is fixed to the second roughened portion by filling the resin material between the forested nano-columns.

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