Secondary battery

Abstract

The present invention relates to a laminated or rectangular secondary battery comprising: a laminated or wound electrode body having a flat shape; an outer container for accommodating the electrode body impregnated with an electrolyte solution; and a first fixing member provided along a target side, the target side being at least one side of the electrode body having a rectangular shape when viewed from the thickness direction of the electrode body. The first fixing member fixes a target end portion, which is an end portion of the electrode body corresponding to the target side, with a length range of 1 / 4 or more of the length of the target side as a target. As a result, it is possible to suppress the expansion of the electrode body and to suppress the leakage of the electrolyte to the outside of the electrode body.

Description

Technical Field

[0001] The present invention relates to a stacked or square secondary battery. Background Art

[0002] Patent Document 1 discloses a battery having a restriction member that restricts the negative electrode and the positive electrode from approaching or separating in the stacking direction of the battery element (electrode body) during charge and discharge.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2003-123843

[0004] In a secondary battery having a stacked or wound electrode body impregnated with an electrolyte solution, if the electrode body swells, the electrolyte solution may leak out of the electrode body. Summary of the invention

[0005] The present invention has been made in view of the above-mentioned technical problems, and an object of the present invention is to provide a secondary battery capable of suppressing expansion of an electrode body and preventing leakage of an electrolyte solution to the outside of the electrode body.

[0006] The secondary battery of the present invention is a stacked or square secondary battery, comprising an electrode body, an outer container and a first fixing member. The electrode body is a stacked or wound electrode body having a flat shape. The outer container accommodates the electrode body impregnated with an electrolyte. The first fixing member is arranged along an object edge, and the object edge is at least one edge of the electrode body having a rectangular shape when observed from the thickness direction of the electrode body. Moreover, the first fixing member fixes the object end with a length range of more than 1 / 4 of the length of the object edge as the object, and the object end is the end of the electrode body corresponding to the object edge.

[0007] In addition, in the present invention, the electrode body can be the stacked type, and the object end includes a lower end and an upper end which are respectively located at the lower side and the upper side in the vertical direction when the secondary battery is mounted on a vehicle, and the length of the first fixing component fixing the lower end in the direction of the object side is greater than the length of the first fixing component fixing the upper end in the direction of the object side.

[0008] In the present invention, the electrode body may be of the wound type, and the target end portion may correspond to one or both of the two target sides parallel to the winding direction of the electrode body.

[0009] In addition, the present invention may also have a second fixing component, which is respectively arranged at a central position in a specific direction and at least two positions relative to the central position and close to either end of the specific direction, wherein the specific direction is the long side direction or the short side direction of the electrode body, and the second fixing component is respectively wound and installed on the electrode body with a length of more than one week along a winding and installation direction orthogonal to the specific direction at the central position and each of the at least two positions, and the tension of the second fixing component wound and installed at the central position is greater than the tension of the second fixing component wound and installed at each of the at least two positions.

[0010] According to the present invention, it is possible to suppress expansion of the electrode body and to suppress leakage of the electrolyte solution to the outside of the electrode body. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a diagram schematically showing an example of the configuration of a secondary battery according to the first embodiment.

[0012] Figure 2 This is a diagram schematically showing another example of the configuration of the secondary battery according to the first embodiment.

[0013] Figure 3 This is a diagram schematically showing an example of the configuration of a secondary battery according to the second embodiment. DETAILED DESCRIPTION

[0014] Embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the same reference numerals are given to common elements in the respective drawings, and repeated descriptions are omitted or simplified.

[0015] 1. Implementation Method 1

[0016] Figure 1 This is a diagram schematically showing an example of the configuration of a secondary battery according to the first embodiment. Figure 1 The secondary battery 10 shown includes an electrode body 11 , an outer container 12 , a pair of electrode terminals 13 , an adhesive tape 14 , and an adhesive tape 15 .

[0017] In Embodiment 1, the electrode body 11 is a flat laminated electrode body (laminated body). The electrode body 11 is formed by, for example, alternately laminating a plurality of positive electrode plates and a plurality of negative electrode plates with separators interposed therebetween in the thickness direction of the electrode body 11 . Figure 1 1 is a diagram showing the electrode body 11 as viewed from the thickness direction. Figure 1 The outer container 12 contains the electrode body 11 impregnated with the electrolyte. A pair of electrode terminals 13 are connected to the tabs of the positive electrode plate and the negative electrode plate, respectively.

[0018] 1.1. Structure of Adhesive Tape (First Fixing Member)

[0019] The adhesive tape 14 is equivalent to an example of the "first fixing member" involved in the present invention. Figure 1 As shown in FIG. 1 , the adhesive tape 14 is provided along the side of the electrode body 11 having a rectangular shape when viewed from the thickness direction, that is, the “target side TS”. Figure 1 In the example shown, the two sides S1 and S2 located at each end of the long side direction D1 of the electrode body 11 correspond to the target side TS. In other examples, the number of target sides TS may be 1, 3, or 4. In addition, the first fixing member (the second fixing member described later also applies) can be any material having adhesive force and being resistant to the electrolyte, and is not limited to the adhesive tape.

[0020] The adhesive tape 14 is provided so as to cover the end of the electrode body 11 corresponding to the target side TS, that is, the "target end TE", and fix the target end TE. Figure 1 In the example shown, the two ends E1 and E2 corresponding to the two sides S1 and S2 correspond to the object end TE. Figure 1 As shown, the adhesive tape 14 fixes the target end TE with a length range of more than 1 / 4 of the length of the target side TS (two sides S1, S2). That is, the length of the adhesive tape 14 along the target side TS only needs to be more than 1 / 4 of the length of the target side TS. For example, the adhesive tape 14 can also be fixed with a length range corresponding to the full length of the target side TS and extend in the length direction of the target side TS.

[0021] The secondary battery 10 may be of a stacked type or a square type. Figure 1 1 shows an example of a stacked type secondary battery 10, in which an electrode body 11 is housed in a pair of flexible films as an outer container 12. Figure 1 As shown, the adhesive tape 14 not only touches the target end TE (each of the two ends E1 and E2) of the electrode body 11, but also touches a part of the outer container 12 located on the lower side of the electrode body 11 (that is, one of the pair of flexible films). In addition, in this example, the adhesive tape 14 is attached in a state where the electrode body 11 is placed on the one of the pair of flexible films. Then, after the electrode body 11 is covered by the other of the pair of flexible films, the three sides of the pair of flexible films are bonded. Then, after the electrolyte is injected into the pair of flexible films, the remaining one side of the pair of flexible films is sealed.

[0022] according to Figure 1In the structure shown, the ends E1 and E2 of the electrode body 11 impregnated with the electrolyte are fixed as the target ends TE by the adhesive tape 14. By fixing the target end TE with the adhesive tape 14 in this way, the expansion of the electrode body 11 at the target end TE can be suppressed. As a result, the leakage of the electrolyte from the inside of the electrode body 11 can be suppressed. Moreover, through the in-depth research of the inventors of the present invention, it is known that by making the length of the adhesive tape 14 more than 1 / 4 of the length of the target side TS, a higher effect can be obtained in suppressing the leakage of the electrolyte. Therefore, according to the secondary battery 10, the leakage of the electrolyte from the inside of the electrode body 11 can be effectively suppressed. As a result, the increase in the resistance increase rate over time caused by repeated charging and discharging of the secondary battery 10 can be suppressed.

[0023] In addition, by providing the adhesive tape 14, the following effects can be obtained. That is, it is possible to suppress the stacking deviation of the stacked electrode body 11 during use of the secondary battery 10. Moreover, by suppressing the expansion of the electrode body 11, it is possible to suppress the leakage of the electrolyte to the outside of the electrode body 11, thereby improving the high-rate resistance of the secondary battery 10. In addition, since the countermeasure is to additionally wrap the adhesive tape 14, it can be achieved with fewer additional parts.

[0024] Alternatively, the secondary battery 10 may be configured as a square battery using a metal or resin casing as the outer container 12. When the secondary battery 10 is square, the adhesive tape 14 may be bonded to the inside of the casing as an example. Figure 1 The adhesive tape shown is also provided at the target end TE (each of the two ends E1 and E2) of the electrode body 11. This produces the same effect as in the above-mentioned example of the stacked secondary battery. In addition, in the stacked secondary battery, the outer container 12 has no restraining force on the electrode body 11. Therefore, compared with the square secondary battery, the effect brought about by the adhesive tape 14 can be well obtained in the stacked secondary battery. This also applies to the adhesive tape 15 (second fixing member) described later.

[0025] In addition, when the raw material of the adhesive tape 14 has the property of not permeating the electrolyte, if the width of the adhesive tape 14 is too large, it will affect the penetration of the electrolyte. Therefore, in this case, the width can be determined in consideration of the influence on the penetration of the electrolyte. This is also true for the adhesive tape 15 (second fixing member) described later.

[0026] 1.2. Structure of Adhesive Tape (Second Fixing Member)

[0027] The adhesive tape 15 is equivalent to an example of the "second fixing member" involved in the present invention. Figure 1As shown, the adhesive tape 15 is respectively provided at the central position P1 in the longitudinal direction D1 of the electrode body 11 and at the positions P2 and P3 close to the respective ends in the longitudinal direction D1 relative to the central position P1. The adhesive tape 15 is respectively wound around the electrode body 11 along the winding and mounting direction D2 orthogonal to the longitudinal direction D1 at the central position P1 and the positions P2 and P3 for a length of one turn or more. Furthermore, the adhesive tape 15 at the central position P1 is wound around the electrode body 11 with a greater tension than the adhesive tapes 15 at the positions P2 and P3.

[0028] In addition, the portion where the adhesive tape 15 is wound and the portion where the adhesive tape 15 is wound are preferably provided at a position other than the arc portion and the edge portion of the electrode body 11. In addition, when the adhesive tape 15 is wound longer than one circle, the length of the portion where the adhesive tape 15 overlaps at the winding end position is preferably 1 / 50 or more of the length of the sides S1 and S2 along the winding installation direction D2.

[0029] The gas generated by the film formation accompanying the decomposition of the electrolyte on the electrodes (positive electrode, negative electrode) is likely to be retained in the central portion of the electrode body 11 (i.e., the portion including the central position P1). As a result, the central portion is likely to swell. More specifically, the secondary battery 10 is enlarged, occupying a large area of ​​the secondary battery 10 ( Figure 1 The greater the difference in aspect ratio of the central portion (the surface represented in ), the easier it is for the central portion to expand. In this regard, according to the structure of the adhesive tape 15, by making the tension of the adhesive tape 15 greater at the central position P1 than at other positions P2 and P3, a structure that makes it easy to move the gas from the center to the end and squeeze it out of the electrode body 11 can be achieved. As a result, the expansion of the central portion that is easy to expand as described above can be effectively suppressed. In more detail, the expansion of the central portion over time (increase in thickness increase rate) caused by repeated charge and discharge of the secondary battery 10 can be suppressed.

[0030] In addition, by providing the adhesive tape 15, the following effects can be obtained. That is, it is possible to suppress the stacking deviation of the stacked electrode body 11 during use of the secondary battery 10. Moreover, by suppressing the expansion of the electrode body 11, it is possible to suppress the leakage of the electrolyte to the outside of the electrode body 11, thereby improving the high-rate resistance of the secondary battery 10. In addition, since the measure of additionally winding the adhesive tape 15 is adopted, it can be achieved with fewer additional parts.

[0031] In addition, Figure 1 In the example shown, the adhesive tape 15 is provided at two positions P2 and P3 in addition to the central position P1. As another example, the adhesive tape 15 may be provided at three or more positions in addition to the central position P1, each of which is close to one end of the electrode body 11 in the longitudinal direction D1, while taking into account that it does not affect the penetration of the electrolyte. Figure 1In the example shown, the long side direction D1 corresponds to the "specific direction" of the present invention, and therefore, the winding and mounting direction D2 of the adhesive tape 15 is a direction orthogonal to the long side direction D1. This can effectively suppress the expansion of the electrode body 11. However, the "specific direction" of the present invention may also be the short side direction (i.e., Figure 1 Therefore, the winding and mounting direction D2 may be a direction perpendicular to the short side direction.

[0032] 1.3. Other examples of placement of adhesive tape (first fixing member)

[0033] Figure 2 This is a diagram schematically showing another example of the configuration of the secondary battery according to the first embodiment. Figure 2 The secondary battery 20 shown is a stacked type like the secondary battery 10, but the arrangement location of the "first fixing member" is different from that of the secondary battery 10. The secondary battery 20 may be either a stacked type or a square type.

[0034] Specifically, in Figure 2 In this example, the lower end E3 and the upper end E4 of the electrode body 11 located at the lower and upper sides respectively when the secondary battery 20 is mounted on the vehicle correspond to the target end TE.

[0035] exist Figure 2 In the example shown, the adhesive tape 21 as the first fixing member is respectively provided at the lower end E3 and the upper end E4. The length of these adhesive tapes 21 is also more than 1 / 4 of the length of the target side TS. On this basis, the length of the adhesive tape 21 fixing the lower end E3 in the direction of the target side TS (side S3) is greater than the length of the adhesive tape 21 fixing the upper end E4 in the direction of the target side TS (side S4).

[0036] according to Figure 2 The structure shown can also suppress the expansion of the electrode body 11 and the leakage of the electrolyte from the inside of the electrode body 11 because of the adhesive tape 21. Here, the elongation of the adhesive tape 21 is the main reason for the increase in the cost of the secondary battery 20. In the example of the secondary battery 20, as described above, the adhesive tape 21 on the lower side of the vertical direction D3 is longer than the adhesive tape 21 on the upper side of the vertical direction D3 when mounted. As a result, it is possible to effectively suppress the leakage of the electrolyte from the lower end E3, which is a side that is easily leaked due to the action of gravity, while considering the cost caused by the configuration of the adhesive tape 21.

[0037] 2. Implementation Method 2

[0038] Figure 3It is a diagram schematically showing an example of the configuration of a secondary battery according to the second embodiment. Figure 3 The secondary battery 30 shown in the figure has a wound electrode body 31 (wound body). That is, the electrode body 31 has a positive electrode body and a negative electrode body arranged with a separator interposed therebetween. Figure 3 The electrode body 11 is wound in a flat shape in the winding direction D4 shown in the figure. Reference numeral 32 illustrates the end of the outer peripheral side of the wound electrode body 11. The electrode body 31 includes a pair of collector plates 33 located at each end in the long side direction D1 (winding axis direction). A pair of electrode terminals 34 are connected to the pair of collector plates 33. In addition, the secondary battery 30 is, for example, square or stacked. Figure 1 and Figure 2 same, Figure 3 This is also a diagram of the electrode body 31 as viewed from the thickness direction of the electrode body 31 .

[0039] exist Figure 3 In the example shown, each end E5 and E6 of the electrode body 31 in the longitudinal direction D1 corresponds to the target end TE. That is, in this example, Figure 3 As shown in the figure, when viewed from the thickness direction of the electrode body 31, the target end TE corresponds to two target sides TS (sides S5 and S6) of the electrode body 31 parallel to the winding direction D4. In addition, adhesive tapes 35 as the first fixing member are respectively provided at the two ends E5 and E6. The length of these adhesive tapes 35 is also more than 1 / 4 of the length of the target side TS (sides S5 and S6).

[0040] according to Figure 3 The structure shown in the figure can effectively suppress the leakage of the electrolyte from each end of the electrode body 31 in the longitudinal direction D1 orthogonal to the winding direction D4 by providing the adhesive tape 35 .

[0041] Alternatively, you can also replace Figure 3 In the illustrated example, the adhesive tape 35 is provided only on one of the two target sides TS (sides S5 and S6 ) parallel to the winding direction D4 of the electrode body 31 .

[0042] The secondary batteries 10, 20, and 30 of the above-mentioned Embodiments 1 and 2 respectively have an adhesive tape 15 (second fixing member). Therefore, according to any of the secondary batteries 10, 20, and 30, the expansion of the electrode body 11 or the electrode body 31 can be effectively suppressed by the combination of the first fixing member and the second fixing member, and the leakage of the electrolyte can be effectively suppressed. However, the "secondary battery" of the present invention may not have the second fixing member, but only have the first fixing member.

Claims

1. A secondary battery, which is a stacked type or a square type, characterized in that: have: The electrode body of the laminated or wound type has a flat shape; an outer container for accommodating the electrode body impregnated with the electrolyte; and The first fixing member is provided along a target side, wherein the target side is at least one side of the electrode body having a rectangular shape when viewed from the thickness direction of the electrode body. The first fixing member fixes a target end portion over a length range of 1 / 4 or more of the target side, the target end portion being an end portion of the electrode body corresponding to the target side.

2. The secondary battery according to claim 1, characterized in that: The electrode body is of the stacked type, The target end portion includes a lower end portion and an upper end portion which are respectively located at a lower side and an upper side in a vertical direction when the secondary battery is mounted on a vehicle. The length of the first fixing member fixing the lower end in the direction of the target side is greater than the length of the first fixing member fixing the upper end in the direction of the target side.

3. The secondary battery according to claim 1, characterized in that: The electrode body is of the wound type, The target end portion corresponds to one or both of the two target sides parallel to the winding direction of the electrode body.

4. The secondary battery according to claim 1 or 2, characterized in that: The invention further comprises a second fixing member, wherein the second fixing member is respectively arranged at a central position in a specific direction and at least two positions close to either end of the specific direction relative to the central position, wherein the specific direction is a long side direction or a short side direction of the electrode body. The second fixing member is wound around the electrode body at the central position and each of the at least two positions along a winding direction orthogonal to the specific direction to have a length of one turn or more. The tension of the second fixing member wound and installed at the central position is greater than the tension of the second fixing member wound and installed at each of the at least two positions.

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