Secondary battery

Abstract

The utility model relates to a secondary battery, which is laminated or square and is provided with a laminated or winding type electrode body, a plurality of electrode plates, a plurality of lead wires and a plurality of lead wires, 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 utility model relates to a stacked or square secondary battery. Background Art

[0002] Patent Document 1 discloses a battery having a restriction member that restricts the approach and separation of a negative electrode and a positive electrode in the stacking direction of battery elements (electrode bodies) during charge and discharge.

[0003] Patent Document 1: Japanese Patent Application Laid-Open 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. Utility Model Content

[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 leakage of an electrolyte to the outside of the electrode body.

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

[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 on 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 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] The embodiments of the present invention will be described with reference to the accompanying drawings. Components common to the various drawings are denoted by the same reference numerals, and overlapping 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 , a first adhesive tape 14 , and a second adhesive tape 15 .

[0017] In Embodiment 1, the electrode body 11 is a flat laminated electrode body (laminate). 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 The electrode body 11 is viewed from the thickness direction. Figure 1 The outer container 12 contains the electrode body 11 impregnated with 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 the Adhesive Tape (First Fixing Member)

[0019] The first adhesive tape 14 is an example of the "first fixing member" involved in the present invention. Figure 1 As shown in FIG. 1 , the first 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 electrode body 11 in the longitudinal direction D1 correspond to the target sides TS. In other examples, the number of target sides TS may be one, three, or four. Furthermore, the first fixing member (and the second fixing member described later) can be any material that has adhesive strength and is resistant to the electrolyte, and is not limited to adhesive tape.

[0020] The first adhesive tape 14 is provided so as to cover the end portion of the electrode body 11 corresponding to the target side TS, that is, the "target end portion TE," and to fix the target end portion TE. Figure 1 In the example shown, the two ends E1 and E2 corresponding to the two sides S1 and S2 correspond to the target end TE. Figure 1 As shown, the first adhesive tape 14 is fixed to the target end TE over a length range that is at least 1 / 4 of the length of the target side TS (the two sides S1 and S2). In other words, the length of the first adhesive tape 14 along the target side TS only needs to be at least 1 / 4 of the length of the target side TS. For example, the first adhesive tape 14 may be fixed over a length range corresponding to the entire length of the target side TS, extending in the longitudinal 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 first adhesive tape 14 not only contacts the target end TE (each of the two ends E1 and E2) of the electrode body 11, but also contacts a portion of the outer container 12 located below the electrode body 11 (i.e., one of the pair of flexible films). In this example, the first adhesive tape 14 is applied while the electrode body 11 is placed on the one of the pair of flexible films. After the electrode body 11 is covered with the other of the pair of flexible films, the three sides of the pair of flexible films are bonded together. After the electrolyte is injected into the pair of flexible films, the remaining 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 first adhesive tape 14. By fixing the target end TE with the first 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 incisive research of the inventors of the present invention, it is known that by making the length of the first 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 charge and discharge of the secondary battery 10 can be suppressed.

[0023] The inclusion of the first adhesive tape 14 also provides the following advantages. Specifically, it can suppress stacking deviations of the stacked electrode assembly 11 during use of the secondary battery 10. Furthermore, by suppressing expansion of the electrode assembly 11, it can suppress leakage of the electrolyte from the electrode assembly 11, thereby improving the high-rate resistance of the secondary battery 10. Furthermore, since this measure involves the additional winding of the first adhesive tape 14, this can be achieved with relatively few additional components.

[0024] Alternatively, the secondary battery 10 may be configured as a square battery using a metal or resin casing as the outer container 12. In the case where the secondary battery 10 is square, the first adhesive tape 14 may be attached to the inner portion of the casing. Figure 1 The adhesive tape shown is similarly provided at the target end TE (each of the two ends E1 and E2) of the electrode body 11. This produces the same effects as in the aforementioned laminated secondary battery example. Furthermore, in the laminated secondary battery, the outer container 12 exerts no restraining force on the electrode body 11. Therefore, compared to prismatic secondary batteries, the laminated secondary battery can achieve the effects of the first adhesive tape 14 to a greater extent. This also applies to the second adhesive tape 15 (second fixing member) described later.

[0025] Furthermore, if the material of the first adhesive tape 14 is impermeable to the electrolyte, an excessively wide width of the first adhesive tape 14 can affect electrolyte penetration. Therefore, in this case, the width should be determined taking into account the impact on electrolyte penetration. This also applies to the second adhesive tape 15 (second fixing member), described later.

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

[0027] The second adhesive tape 15 is an example of the "second fixing member" involved in the present invention. Figure 1As shown, the second adhesive tape 15 is provided at a central position P1 in the longitudinal direction D1 of the electrode body 11, and at positions P2 and P3 near each end of the longitudinal direction D1 relative to the central position P1. The second adhesive tape 15 is wound around the electrode body 11 along a winding direction D2 perpendicular to the longitudinal direction D1, for a length of one full revolution or more, at the central position P1 and at positions P2 and P3. Furthermore, the second adhesive tape 15 at the central position P1 is wound around the electrode body 11 with a greater tension than the second adhesive tape 15 at positions P2 and P3.

[0028] The portions where the second adhesive tape 15 is wound and where it ends are preferably located at locations other than the curved portion and edge portion of the electrode body 11. Furthermore, when the second adhesive tape 15 is wound longer than one revolution, the length of the portion where the second adhesive tape 15 overlaps at the end of the winding is preferably at least 1 / 50 of the length of the sides S1 and S2 along the winding direction D2.

[0029] The gas generated by the film formation accompanying the decomposition of the electrolyte on the electrodes (positive electrode, negative electrode) tends to accumulate in the central portion of the electrode body 11 (i.e., the portion including the central position P1). As a result, the central portion tends 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 between the center and the center (the surface shown in FIG), the more likely the center portion is to expand. Regarding this point, the structure of the second adhesive tape 15 described above, by making the tension of the second adhesive tape 15 greater at the center position P1 than at other positions P2 and P3, can achieve a structure that facilitates the movement of gas from the center to the ends and squeezes it out of the electrode body 11. As a result, the expansion of the center portion, which is prone to expansion as described above, can be effectively suppressed. More specifically, the time-dependent expansion (increase in the rate of thickness increase) of the center portion caused by repeated charge and discharge of the secondary battery 10 can be suppressed.

[0030] The inclusion of the second adhesive tape 15 also provides the following advantages. Specifically, it can suppress stacking deviations of the stacked electrode assembly 11 during use of the secondary battery 10. Furthermore, by suppressing the expansion of the electrode assembly 11, it can suppress leakage of the electrolyte outside the electrode assembly 11, thereby improving the high-rate resistance of the secondary battery 10. Furthermore, since this measure involves the additional winding of the second adhesive tape 15, this can be achieved with relatively few additional components.

[0031] In addition, Figure 1 In the example shown, the second adhesive tape 15 is provided at two positions P2 and P3 in addition to the central position P1. As another example, the second 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 1 In the example shown, the longitudinal direction D1 corresponds to the "specific direction" of the present invention. Therefore, the winding and mounting direction D2 of the second adhesive tape 15 is perpendicular to the longitudinal direction D1. This effectively suppresses the expansion of the electrode body 11. However, the "specific direction" of the present invention may also be the transverse direction (i.e., the transverse direction). 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 Locations for 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 placement of the "first fixing member" is different from that of the secondary battery 10. The secondary battery 20 may be a stacked type or a rectangular type.

[0034] Specifically, in Figure 2 In this example, the lower end E3 and the upper end E4 of the electrode body 11, which are 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, adhesive tape 21, serving as the first fixing member, is provided at the lower end E3 and the upper end E4. The length of these adhesive tapes 21 is also at least one-quarter the length of the target side TS. Furthermore, the adhesive tape 21 securing the lower end E3 is longer in the direction of the target side TS (side S3) than the adhesive tape 21 securing the upper end E4.

[0036] according to Figure 2 The structure shown also suppresses expansion of the electrode body 11 and leakage of the electrolyte from the interior of the electrode body 11 due to the presence of the adhesive tape 21. The lengthening of the adhesive tape 21 is a major factor contributing to the increased 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 in the vertical direction D3 is longer than the adhesive tape 21 on the upper side in the vertical direction D3 when mounted. This effectively suppresses leakage of the electrolyte from the lower end E3, which is prone to leakage due to gravity, while taking into account the cost associated with the placement of the adhesive tape 21.

[0037] 2. Implementation Method 2

[0038] Figure 3A 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. Reference numeral 32 shows the end portion of the outer peripheral side of the wound electrode body 11. The electrode body 31 includes a pair of current collector plates 33 located at each end in the longitudinal direction D1 (winding axis direction). A pair of electrode terminals 34 are connected to the pair of current collector plates 33. In addition, the secondary battery 30 may be, 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, the ends E5 and E6 of the electrode body 31 in the longitudinal direction D1 correspond to the target end TE. Figure 3 As shown, when viewed in the thickness direction of the electrode body 31, the target end TE corresponds to the two target sides TS (sides S5 and S6) of the electrode body 31 that are parallel to the winding direction D4. Furthermore, adhesive tapes 35, serving as first fixing members, are provided at the two ends E5 and E6, respectively. The length of these adhesive tapes 35 is also at least 1 / 4 the length of the target sides TS (sides S5 and S6).

[0040] according to Figure 3 The illustrated configuration can effectively suppress leakage of the electrolyte from each end of the electrode assembly 31 in the longitudinal direction D1 perpendicular to the winding direction D4 by providing the adhesive tape 35 .

[0041] Alternatively, you can 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 assembly 31 .

[0042] The secondary batteries 10, 20, and 30 of the first and second embodiments above each include a second adhesive tape 15 (second fixing member). Therefore, in any of the secondary batteries 10, 20, and 30, the combination of the first and second fixing members effectively suppresses expansion of the electrode body 11 or 31, effectively preventing leakage of the electrolyte. However, the "secondary battery" of the present invention may include only the first fixing member, without the second 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 housing the electrode body impregnated with the electrolyte; and The first fixing member is provided along a target side, which 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 in a length range that is not less than 1 / 4 of the length of the target side, and the target end portion is an end portion of the electrode assembly corresponding to the target side.

2. The secondary battery according to claim 1, wherein The electrode body is of the stacked type, The target end portion includes a lower end portion and an upper end portion located at a lower side and an upper side in a vertical direction, respectively, 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, wherein 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 assembly.

4. The secondary battery according to claim 1 or 2, characterized in that The electrode assembly further comprises a second fixing member, the second fixing member being provided 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 the long side direction or the short side direction of the electrode assembly. 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 perpendicular to the specific direction to have a length of one turn or more. The tension of the second fixing member wound and mounted at the central position is greater than the tension of the second fixing member wound and mounted at each of the at least two positions.

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