Secondary battery

Abstract

A secondary battery comprises an electrode body, a receiving case that accommodates the electrode body, and a support member disposed between the receiving case and the electrode body. The support member includes a pair of support plates that support the electrode body and a protrusion that protrudes from the pair of support plates toward the inner surface of the receiving case and contacts the inner surface. The protrusion has a rib structure or a shape that bulges toward the inner surface.

Description

Technology Field

[0001] The present disclosure relates to a secondary battery. Background Technology

[0002] As a conventional secondary battery, Japanese Patent Publication No. 2018-041596 discloses a configuration in which a resistive member is disposed between the periphery of an insulating film container surrounding a wound electrode body and a battery case, thereby restricting the movement of fluid present in the gap by closing the gap between the insulating film and the battery case. The problem to be solved

[0003] The resistive member described in Japanese Patent Publication No. 2018-041596 restricts the movement of fluid, and there is a concern that when the secondary battery vibrates, the insulating film container also vibrates, causing the wound electrode body to move. Furthermore, when the electrode body is formed larger in conjunction with increased capacity, it becomes difficult to suppress the movement of the electrode body.

[0004] The present disclosure is made in consideration of the above-mentioned problems, and the objective of the present disclosure is to provide a secondary battery capable of suppressing the movement of an electrode body. means of solving the problem

[0005] A secondary battery based on the present disclosure comprises an electrode body, a receiving case for receiving the electrode body, and a support member disposed between the receiving case and the electrode body. The support member comprises a pair of support plates for supporting the electrode body and a protrusion that protrudes from the pair of support plates toward an inner surface of the receiving case and contacts the inner surface. The protrusion has a rib structure or a shape that bulges toward the inner surface.

[0006] In a secondary battery based on the present disclosure, the electrode body is a wound electrode body wound around a winding axis and may have a pair of curved portions located at both ends in the width direction perpendicular to the winding axis. The pair of support plates may be disposed on the outer side of the pair of curved portions in the width direction.

[0007] In a secondary battery based on the present disclosure, the support member may include a plate connecting the pair of support plates. The pair of support plates and the plate may be integrated. Effects of the invention

[0008] According to the present disclosure, a secondary battery capable of suppressing the movement of an electrode body can be provided. Brief explanation of the drawing

[0009] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention are described below with reference to the accompanying drawings, and like reference numerals indicate like elements. FIG. 1 is an exploded perspective view of a secondary battery related to Embodiment 1; FIG. 2 is a schematic cross-sectional view of a secondary battery along the line II-II shown in FIG. 1; FIG. 3 is a schematic cross-sectional view of a secondary battery along line III-III shown in FIG. 1; FIG. 4 is a schematic cross-sectional view showing a support member of a secondary battery related to Embodiment 2; FIG. 5 is a schematic cross-sectional view showing a support member of a secondary battery related to Embodiment 3. Specific details for implementing the invention

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In addition, in the embodiments shown below, the same reference numerals in the drawings are assigned to identical or common parts, and their descriptions are not repeated.

[0011] Embodiment 1

[0012] FIG. 1 is an exploded perspective view of a secondary battery related to Embodiment 1. FIG. 2 is a schematic cross-sectional view of a secondary battery along line II-II shown in FIG. 1. FIG. 3 is a schematic cross-sectional view of a secondary battery along line III-III shown in FIG. 1.

[0013] The secondary battery (100) is a so-called prismatic battery. The secondary battery (100) is a battery configured to be rechargeable, such as a lithium-ion battery or a nickel-hydrogen battery. The secondary battery (100) is used, for example, as a cell included in a storage module mounted on an electrified vehicle.

[0014] The secondary battery (100) comprises a case body (1), an electrode assembly (2), a cover assembly (3), connecting members (4A, 4B), a support member (5), and a plurality of insulating protection members (6).

[0015] The case body (1) has a roughly box-shaped opening facing upward. The opening of the case body (1) is closed by a cover assembly (3). The case body (1) accommodates an electrode assembly (2), connecting members (4A, 4B), and a plurality of insulating protection members (6) inside.

[0016] The cover assembly (3) is positioned at the opening of the case body (1). The cover assembly (3) has a first external terminal (31A), a second external terminal (31B), a cover plate (32), fixing members (35A, 35B), and a plurality of hook-and-fit parts (38). The cover plate (32) has a plate-like shape. The cover plate (32) is fixed to the case body (1), for example, by welding. The cover plate (32) and the case body (1) form a receiving case that accommodates a plurality of electrode bodies (10) inside.

[0017] A pressure opening valve (33) is formed on the cover plate (32). The pressure opening valve (33) is formed to be openable when the internal pressure of the case body (1) becomes greater than or equal to a predetermined value.

[0018] A first external terminal (31A) and a second external terminal (31B) are formed on the cover plate (32). The first external terminal (31A) and the second external terminal (31B) are spaced apart in a first direction. The first direction (DR1) is a direction perpendicular to the winding axis of the electrode body (10) described later, and is parallel to the width direction of the electrode body (10).

[0019] The first external terminal (31A) is, for example, a positive terminal. The first external terminal (31A) is fixed to the cover plate (32) by a fixing member (35A). The fixing member (35A) has an annular shape. The fixing member (35A) is, for example, made of an insulating member. The fixing member (35A) is fixed by being caught in a through hole formed in the cover plate (32).

[0020] The second external terminal (31B) is, for example, a negative terminal. The second external terminal (31B) is fixed to the cover plate (32) by a fixing member (35B). The fixing member (35B) has an annular shape. The fixing member (35B) is, for example, made of an insulating member. The fixing member (35B) is fixed by being caught in a through hole formed in the cover plate (32).

[0021] On the inner surface side of the cover plate (32), an insulating member (37) and a hook-and-fit part (38) are formed. The insulating member (37) prevents the flat plate part (41) of the connecting members (4A, 4B) from being electrically connected to the cover plate (32). The hook-and-fit part (38) extends along the second direction (DR2). The second direction (DR2) is a direction orthogonal to the first direction (DR1). The hook-and-fit part (38) has a block shape with a long rod shape. The hook-and-fit part (54) of the support member (5), which will be described later, is hooked into the hook-and-fit part (38). By doing so, the support member (5) is fixed to the cover plate (32).

[0022] The electrode assembly (2) includes a plurality of electrode bodies (10). Each of the plurality of electrode bodies (10) is, for example, a wound electrode body wound around a winding axis. The wound electrode body has a pair of curved portions (11) at both ends in the width direction perpendicular to the winding axis.

[0023] In addition, the winding axis is parallel to the third direction (DR3). The third direction (DR3) is a direction orthogonal to the first direction (DR1) and the second direction (DR2). In this embodiment, the third direction (DR3) is parallel to the vertical direction.

[0024] The wound electrode body comprises a positive electrode member, a negative electrode member, and a separator wound together. A positive electrode active material layer is coated on the positive electrode member, and a negative electrode active material layer is coated on the negative electrode member.

[0025] In addition, the electrode body (10) is not limited to a wound electrode body, but may be a laminate in which a positive electrode member and a negative electrode member are alternately stacked with a separator interposed.

[0026] Each electrode body (10) has a plurality of first tabs (21A) and a plurality of second tabs (21B) formed therein. The plurality of first tabs (21A) extend from a positive electrode member. The plurality of second tabs (21B) extend from a negative electrode member. An active material layer is not formed on each of the plurality of first tabs (21A) and the plurality of second tabs (21B).

[0027] A set of electrode bodies (10) is formed by two electrode bodies (10) arranged in a second direction (DR2). Two sets of electrode bodies (10) are arranged in the second direction (DR2). For each set of electrode bodies (10), a plurality of first taps (21A) and a plurality of second taps (21B) are each connected.

[0028] The bundled plurality of first tabs (21A) and plurality of second tabs (21B) are bent into a roughly U shape so as to face outward in the second direction (DR2) and then inward in the second direction.

[0029] A plurality of first taps (21A) are connected to the connecting member (4A). Specifically, a plurality of first taps (21A) are connected to the rear side of the flat plate portion (41) of the connecting member (4A). A plurality of second taps (21B) are connected to the connecting member (4B). Specifically, a plurality of second taps (21B) are connected to the rear side of the flat plate portion (41) of the connecting member (4B). The rear side of the flat plate portion (41) is the main surface facing the electrode body (10).

[0030] The connecting member (4A, 4B) is composed of a conductive member. The connecting member (4A, 4B) has a flat plate (41) and a protrusion (42). The flat plate (41) has a roughly U-shaped form with the inner side of the first direction (DR1) open. The protrusion (42) protrudes from the flat plate (41) toward one side of the third direction (DR3). That is, the protrusion (42) protrudes from the flat plate (41) toward the cover plate (32).

[0031] The protrusion (42) of the connecting member (4A) is connected to the first external terminal (31A). The protrusion (42) of the connecting member (4B) is connected to the second external terminal (31B).

[0032] A support member (5) is disposed between a plurality of electrode bodies (10) and the receiving case. The support member (5) supports the electrode assembly (2). The support member (5) has insulating properties and prevents the electrode assembly (2) from contacting the inner surface of the receiving case and short-circuiting. The detailed structure of the support member (5) will be described later.

[0033] The insulating protective member (6) is positioned between the plate (51) of the support member (5) and the protrusion (42) of each connecting member (4A, 4B). In the assembly process of the secondary battery (100), even if a metal foreign substance enters into the recess located inside the protrusion (42), the insulating protective member (6) is positioned so that the metal foreign substance can be prevented from moving from the recess to the electrode assembly (2). This prevents a short circuit of the electrode assembly (2) caused by the foreign substance. The insulating protective member (6) is positioned below the protrusion (42) of each connecting member (4A, 4B) and is clamped by the flat plate (41) of each connecting member (4A, 4B) and the mounting portion (52) of the support member (5) described later. Additionally, the insulating protective member (6) may be placed within the concave portion on the inner side of the protrusion (42).

[0034] As for the insulating protective member (6), a foamed material having insulating properties, a rubber material, or an adhesive-shaped material that is coated and solidified can be appropriately adopted.

[0035] The support member (5) includes a plate (51), a mounting portion (52), an elongated portion (53A, 53B), a pair of fitting portions (54), a pair of support plates (55), and a protrusion (57).

[0036] The plate (51) extends along the first direction (DR1). The plate (51) faces the upper surface of a plurality of electrode bodies (10). The plate (51) is composed of, for example, an insulating resin member.

[0037] In the plate (51), a mounting portion (52) is formed at a position corresponding to the protrusion (42) of the connecting member (4A, 4B). Each mounting portion (52) protrudes from the plate (51) toward the cover plate (32). An insulating protective member (6) is disposed in each mounting portion (52). Each mounting portion (52) is also composed of a resin member having insulating properties.

[0038] Additionally, the plate (51) has an elongated portion (53A, 53B) formed therein that extends outward in the second direction (DR2). The elongated portion (53A, 53B) extends from the plate (51) toward one side of the third direction (the side of the cover plate (32)) and extends outward in the second direction (DR2).

[0039] The ejection portions (53A, 53B) are composed of an insulating resin member. The ejection portion (53A) is positioned at a location corresponding to a plurality of first tabs (21A) bent into a U-shape and extends into the U-shaped inner region of the plurality of first tabs (21A). The ejection portion (53B) is positioned at a location corresponding to a plurality of second tabs (21B) bent into a U-shape and extends into the U-shaped inner region of the plurality of second tabs (21B). By doing so, the plurality of first tabs (21A) and the plurality of second tabs (21B) can be pressed toward the electrode assembly (2), thereby preventing the electrode body (10) from being short-circuited.

[0040] A pair of engaging portions (54) are formed at both ends of the plate (51) in the first direction (DR1). A pair of engaging portions (54) protrude toward the cover plate (32). A pair of engaging portions (54) are engaged with the aforementioned engaging portion (38). By doing so, the support member (5) can be stably placed inside the receiving case.

[0041] A pair of support plates (55) supports a plurality of electrode bodies (10). A pair of support plates (55) is located on the outside of a pair of curved portions (11) in the width direction of the electrode bodies (10). A pair of support plates (55) is positioned between a plurality of electrode bodies (10) and a pair of side wall portions (1b) of the case body (1).

[0042] A pair of support plates (55) sandwich a plurality of electrode bodies (10) in the width direction. A pair of support plates (55) are formed at both ends of the plate (51) in the first direction (DR1). A pair of support plates (55) extend toward the other side in the third direction (DR3). A pair of support plates (55) extend toward the bottom wall portion (1a) of the case body (1). A pair of support plates (55) are composed of an insulating resin member.

[0043] The protrusion (57) protrudes from each support plate (55) toward the inner surface of the receiving case and comes into contact with the inner surface. Specifically, from the support plate (55) located on one side of the first direction, the protrusion (57) protrudes toward the inner surface of the side wall (1b) located on one side of the first direction and comes into contact with the inner surface. From the support plate (55) located on the other side of the first direction (DR1), the protrusion (57) protrudes toward the inner surface of the side wall (1b) located on the other side of the first direction and comes into contact with the inner surface. The protrusion (57) has a rib structure. That is, a plurality of ribs are formed on each support plate (55), and the protrusion (57) is formed by the plurality of ribs. The protrusion (57) may be formed integrally with the support plate (55).

[0044] As described above, in this embodiment, a protrusion (57) having a rib structure formed on a pair of support plates (55) arranged on both outer sides of the electrode body (10) in the first direction (DR1) comes into contact with the inner surface of the pair of side wall portions (1b), thereby pressing the pair of support plates (55) toward the inside of the first direction (DR1). By doing so, the pair of support plates (55) can be used to sandwich a plurality of electrode bodies (10) between them, thereby suppressing the movement of the electrode bodies (10).

[0045] Additionally, a pair of support plates (55) are positioned on the outer side of a pair of curved sections (11) in the width direction to support the electrode body (10). Since the pair of curved sections (11) are prone to vibration, the movement of the electrode body (10) can be effectively suppressed by clamping the pair of curved sections (11) with the pair of support plates (55).

[0046] Additionally, the plate (51) and the pair of support plates (55) may be integrated. That is, the plate (51) and the pair of support plates (55) may be integrally molded by a resin member. Also, the protrusion (57) may also be integrally molded with the plate (51) and the pair of support plates (55).

[0047] By connecting a pair of support plates (55) with a plate (51), the position of the pair of support plates (55) can be stabilized. Additionally, the electrode body (10) can be moved toward the cover plate (32) by the plate (51). Furthermore, by integrally molding the plate (51) and the pair of support plates (55), the configuration of the support member (5) can be simplified.

[0048] Embodiment 2

[0049] FIG. 4 is a schematic cross-sectional view showing a support member of a secondary battery related to Embodiment 2. With reference to FIG. 4, a support member (5X) related to Embodiment 2 will be described.

[0050] The support member (5X) can be used in the secondary battery (100) instead of the support member (5) related to Embodiment 1. The support member (5X) has a different configuration of the protrusion (57X) compared to the support member (5) related to Embodiment 1. The other configurations are almost identical.

[0051] The protrusion (57X) has a shape that bulges toward the inner surface of the storage case described above. From the support plate (55) located on one side of the first direction, the protrusion (57X) bulges toward the inner surface of the side wall (1b) located on one side of the first direction. From the support plate (55) located on the other side of the first direction (DR1), the protrusion (57X) bulges toward the inner surface of the side wall (1b) located on the other side of the first direction.

[0052] In the protrusion (57X), the portion in contact with the inner surface is formed to be approximately flat. As a result, the protrusion (57X) can contact the inner surface over a large area. Consequently, the electrode body (10) can be supported more stably.

[0053] Embodiment 3

[0054] FIG. 5 is a schematic cross-sectional view showing a support member of a secondary battery related to Embodiment 3. With reference to FIG. 5, the support member (5Y) related to Embodiment 3 will be described.

[0055] The support member (5Y) can be used in the secondary battery (100) instead of the support member (5) related to Embodiment 1. The support member (5Y) has a different configuration of the protrusion (57Y) compared to the support member (5) related to Embodiment 1. The other configurations are almost identical.

[0056] The protrusion (57Y) has a shape that bulges toward the inner surface of the storage case described above. From the support plate (55) located on one side of the first direction, the protrusion (57Y) bulges toward the inner surface of the side wall (1b) located on one side of the first direction. From the support plate (55) located on the other side of the first direction (DR1), the protrusion (57Y) bulges toward the inner surface of the side wall (1b) located on the other side of the first direction.

[0057] In the protrusion (57Y), the portion that contacts the inner surface is formed in a roughly arc shape or an elliptical arc shape. Thus, the support member (5Y) can flexibly respond to manufacturing errors in the internal dimensions of the receiving case. Even if there are dimensional errors, the protrusion (57Y) can contact the inner surface of the receiving case while bending and deforming.

[0058] The embodiments disclosed herein are exemplary in all respects and are not restrictive. The scope of the invention is defined by the claims, and includes all modifications within the equivalent meaning and scope of the claims.

Claims

Claim 1 A secondary battery comprising an electrode body, a receiving case for receiving the electrode body, and a support member disposed between the receiving case and the electrode body, wherein the support member comprises a pair of support plates for supporting the electrode body and a protrusion that protrudes from the pair of support plates toward the inner surface of the receiving case and contacts the inner surface, and wherein the protrusion has a rib structure or a shape bulging toward the inner surface. Claim 2 A secondary battery according to claim 1, wherein the electrode body is a wound electrode body wound around a winding axis and has a pair of curved portions located at both ends in the width direction perpendicular to the winding axis, and the pair of support plates are disposed on the outer side of the pair of curved portions in the width direction. Claim 3 In claim 2, the support member comprises a plate connecting the pair of support plates, and the pair of support plates and the plate are integrated, a secondary battery.

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