Secondary batteries

Abstract

To provide a secondary battery that can ensure insulation between the battery terminals and the electrode body while keeping costs down. [Solution] A secondary battery 1 comprises a housing 11, a lid 12, a flat-shaped electrode body 20, and battery terminals 30, 31. The electrode body 20 is housed within the housing 11, and terminal connection portions 21, 22 are provided at both ends of a second direction X perpendicular to a first direction which is the thickness direction of the electrode body 20. The battery terminals 30, 31 have a mounting portion 41 attached to the lid 12, an electrode connection portion 42 joined to the terminal connection portion, and a bent portion R between the mounting portion 41 and the electrode connection portion 42 which is convex in the direction away from the electrode body 20 in the second direction X. As the electrode body 20 moves along a third direction Z perpendicular to both the first and second directions X, the distance between the bent portion R and the electrode body 20 in the second direction X changes, and as the electrode body 20 moves toward the lid 12, the bent portion R moves toward the electrode body 20.

Description

Technical Field

[0001] The present invention relates to secondary batteries.

Background Art

[0002] In recent years, secondary batteries such as lithium-ion secondary batteries have been suitably used as power sources for driving vehicles such as battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), etc. In this type of secondary battery, for example, an electrode body is housed in a case. As a secondary battery having such a configuration, for example, the secondary battery described in Patent Document 1 below is disclosed.

[0003] The secondary battery (referred to as a "prismatic battery" in the document) described in Patent Document 1 has an electrode body (referred to as a "flat electrode group" in the document) housed in a battery case (referred to as a "prismatic outer can" in the document), and a battery terminal (referred to as a "current collector" in the document) is connected to the electrode body. Further, in the secondary battery described in Patent Document 1, an insulating member is disposed between the battery case and the battery terminal inside the battery case to prevent the occurrence of an internal short circuit.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In secondary batteries, variations in the dimensions of individual components and variations in load when inserting the electrode body into the battery case can lead to contact between the battery terminals and the electrode body during insertion, potentially damaging the electrode foil. To address this, it is necessary to achieve high dimensional accuracy so that the battery terminals do not come into contact with the electrode body, or to add an insulating material between the battery terminals and the electrode body, as in the secondary battery described in Patent Document 1, which incurs additional costs. Therefore, there has been room for improvement in ensuring insulation between the battery terminals and the electrode body in secondary batteries.

[0006] This invention has been made in view of the above circumstances, and its purpose is to provide a secondary battery that can ensure insulation between the battery terminals and the electrode body while keeping costs down. [Means for solving the problem]

[0007] The characteristic configuration of the secondary battery according to the present invention for achieving the above objective is: A secondary battery comprising a housing having an opening, a lid attached to the opening of the housing, a flat electrode body formed by stacking a positive electrode plate and a negative electrode plate with a separator in between, and battery terminals attached to the lid, The electrode body is Housed within the aforementioned enclosure, Terminal connection portions are provided at both ends of a second direction perpendicular to the first direction, which is the thickness direction of the electrode body. The aforementioned battery terminals are, A mounting portion attached to the lid, The electrode connection portion is joined to the terminal connection portion, Between the mounting portion and the electrode connection portion, there is a bent portion that is convex in the direction away from the electrode body in the second direction, As the electrode body moves along a third direction perpendicular to both the first and second directions, the distance between the bent portion and the electrode body in the second direction changes, and as the electrode body moves toward the cover, the bent portion moves toward the electrode body.

[0008] According to the above-described configuration, the battery terminal maintains a state in which the bent portion provided between the mounting portion and the electrode connection portion is bent away from the electrode body (outward). This eliminates the need to ensure high dimensional accuracy to avoid contact between the battery terminal and the electrode body, or to place insulating material between the battery terminal and the electrode body, thus ensuring insulation between the battery terminal and the electrode body while keeping costs down.

[0009] Further characteristic features of the secondary battery according to the present invention are: The battery terminal has a metal plate between the mounting portion and the electrode connection portion. The aforementioned metal plate is bent at one or more points to form one or more hinge portions. The aforementioned bent portion is characterized by the fact that one of the hinge portions is convex in a direction away from the electrode body.

[0010] According to the above characteristic configuration, while securing the cross-sectional area for reducing electrical resistance, the second moment of area is reduced, making it easier for the bent portion to separate from the electrode body when the electrode body moves in the direction approaching the cover body.

[0011] Further characteristic features of the secondary battery according to the present invention are: The battery terminal has a leaf spring between the mounting portion and the electrode connection portion. The aforementioned bent portion is characterized by the fact that the leaf spring is convex in a direction away from the electrode body.

[0012] According to the above-described configuration, a bent portion can be formed in the leaf spring due to the spring properties of the leaf spring, making it easy to create a bent portion that separates from the electrode body when the electrode body moves in the direction of approaching the lid body.

[0013] Further characteristic features of the secondary battery according to the present invention are: An insulating material is covered on the inner surface of the housing that faces the bent portion of the battery terminal. In the bending portion, a stopper member that contacts the insulating member is attached in a state where the electrode body has moved in a direction approaching the lid body.

[0014] According to the above characteristic configuration, when components (such as an electrode body) housed in the housing vibrate due to external disturbances, the vibration is suppressed by the friction between the stopper member and the insulating member on the inner surface of the housing.

[0015] A further characteristic configuration of the secondary battery according to the present invention is A conductive member is provided on the surface of the insulating member that covers the inner surface of the housing, There are a pair of the stopper members, and the stopper members are conductive.

[0016] According to the above characteristic configuration, a conduction path through which electricity flows in the order of one stopper member, the conductive member, and the other stopper member is formed, so that the electrical resistance can be reduced.

Effects of the Invention

[0017] As described above, according to the secondary battery according to the present invention, the insulation between the battery terminal and the electrode body can be ensured inside the battery case while suppressing costs.

Brief Description of the Drawings

[0018] [Figure 1] It is an exploded perspective view of a secondary battery according to the first embodiment. [Figure 2] It is a diagram showing a current collector terminal. [Figure 3] It is a diagram showing a state before inserting an electrode body to which a current collector terminal is connected into a battery case. [Figure 4] It is a diagram showing a state after inserting an electrode body to which a current collector terminal is connected into a battery case. [Figure 5] It is a partial cross-sectional view of a secondary battery according to the second embodiment. [Figure 6] It is a partial cross-sectional view of a secondary battery according to the third embodiment. [Figure 7]This figure shows the state before inserting the electrode body, to which the current collection terminals are connected, into the battery case according to the fourth embodiment. [Figure 8] This figure shows the state after inserting an electrode body with current collection terminals connected to it into the battery case according to the fourth embodiment. [Modes for carrying out the invention]

[0019] The secondary battery according to this embodiment will be described below with reference to the drawings. In the following description, the secondary battery will be described as a lithium-ion secondary battery. Furthermore, in order to clarify the explanation, the descriptions and drawings have been simplified as appropriate.

[0020] [Overview of secondary battery 1] Figure 1 is an exploded perspective view of a secondary battery 1 equipped with an electrode body 20 according to this embodiment. In the following description, the direction parallel to the height direction of the secondary battery 1 is defined as the Z-axis direction, the direction parallel to the longitudinal direction of the electrode body 20 is defined as the X-axis direction, and the direction parallel to the thickness direction of the electrode body 20 is defined as the Y-axis direction. The Z-axis direction is parallel to the vertical direction, the X-axis direction and the Y-axis direction are orthogonal to each other, and the Z-axis direction is parallel to the horizontal direction. In the following, one side in the X-axis direction is referred to as the X1 side, and the other side in the X-axis direction is referred to as the X2 side. In this embodiment, the Y-axis direction corresponds to the "first direction", the X-axis direction to the "second direction", and the Z-axis direction to the "third direction".

[0021] As shown in Figure 1, the secondary battery 1 comprises a battery case 10 consisting of a case body 11 and a sealing plate 12, battery terminals PS and NS consisting of metal external terminals 25 and 26 and current collector terminals 30 and 31, and an electrode body 20. The secondary battery 1 is a sealed type secondary battery in which the electrode body 20 and current collector terminals 30 and 31 are housed inside the case body 11, the opening of the case body 11 is sealed with the sealing plate 12, and then an electrolyte is injected into the inside of the case body 11.

[0022] [Configuration of battery case 10] As shown in Figure 1, the battery case 10 of this embodiment consists of a case body 11 with a roughly rectangular parallelepiped shape and an open top, and a sealing plate 12 that seals the opening of the case body 11. In the battery case 10 of this embodiment, both the case body 11 and the sealing plate 12 are made of aluminum, but are not limited to this. Various metals and alloys can be used as materials for the case body 11 and the sealing plate 12. In the case body 11, the inner surfaces 11a and 11b (in other words, the inner surfaces 11a and 11b on both sides in the X-axis direction) facing the current collection terminals 30 and 31 are covered with an insulating member 51 (see Figures 3 and 4). The material of the insulating member 51 is not particularly limited as long as insulation between the case body 11 and the current collection terminals 30 and 31 can be ensured, and known materials used as insulating members for secondary batteries can be used. In this embodiment, the case body 11 corresponds to the "housing," and the sealing plate 12 corresponds to the "lid."

[0023] In this embodiment, the sealing plate 12 has a shape corresponding to the shape of the opening of the case body 11 and is configured to seal the opening of the case body 11. Specifically, the sealing plate 12 in this embodiment consists of a flat plate member that is substantially rectangular in view in the Z-axis direction. The sealing plate 12 has a positive electrode battery terminal PS disposed on one end in the longitudinal direction (X-axis direction) and a negative electrode battery terminal NS disposed on the other end in the longitudinal direction.

[0024] [Configuration of electrode body 20] In this embodiment, the electrode body 20 is composed of a wound body formed by winding together long, strip-shaped positive electrode plates and negative electrode plates stacked with a strip-shaped separator in between, and then compressing them into a flattened shape. As shown in Figure 1, the electrode body 20 of this embodiment is substantially rectangular in thickness direction (Y-axis direction), and a positive electrode terminal connection portion 21 (an example of a terminal connection portion) is formed on one end in the longitudinal direction (X-axis direction) in thickness direction, and a negative electrode terminal connection portion 22 (an example of a terminal connection portion) is formed on the other end.

[0025] In this embodiment, the electrode body 20 is housed inside the case body 11 in a position where its thickness and longitudinal directions are parallel to the horizontal direction, while covered with an insulating film. Furthermore, the electrode body 20 and the case body 11 are insulated from each other by an insulating film (not shown).

[0026] [Configuration of the positive and negative electrodes] In this embodiment, the secondary battery 1 comprises a positive electrode battery terminal PS consisting of a positive electrode external terminal 25 and a positive electrode current collector terminal 30, a positive electrode insulating member 35, and a positive electrode gasket 32 ​​as the positive electrode configuration. The secondary battery 1 also comprises a negative electrode battery terminal NS consisting of a negative electrode external terminal 26 and a negative electrode current collector terminal 31, a negative electrode insulating member 36, and a negative electrode gasket 33 as the negative electrode configuration (see Figures 3 and 4).

[0027] In the secondary battery 1 of this embodiment, the positive electrode external terminal 25 and the positive electrode current collector terminal 30, and the negative electrode external terminal 26 and the negative electrode current collector terminal 31 are integrated by crimping to form the respective battery terminals PS and NS. In this embodiment, both the positive electrode external terminal 25 and the positive electrode current collector terminal 30 that constitute the positive electrode battery terminal PS are made of aluminum. On the other hand, for the negative electrode battery terminal NS, the negative electrode external terminal 26 is made of aluminum, and the negative electrode current collector terminal 31 is made of copper.

[0028] In this embodiment, the positive external terminal 25 and the negative external terminal 26 are insulated from the sealing plate 12 by the positive gasket 32 ​​and the negative gasket 33. Furthermore, the positive current collector terminal 30 and the negative current collector terminal 31 are insulated from the sealing plate 12 by the positive insulating member 35 and the negative insulating member 36. Airtightness is maintained between each battery terminal PS, NS and the sealing plate 12 by the insulating members 35, 36 and the gaskets 32, 33. In this embodiment, the insulating members 35, 36 and the gaskets 32, 33 are made of PFA resin, but are not limited to this. The materials of the insulating members 35, 36 and the gaskets 32, 33 can be any material that has insulating properties.

[0029] As shown in Figure 2, in this embodiment, each current collector terminal 30, 31 is constructed by bending a plate-shaped member. Specifically, each current collector terminal 30, 31 is composed of a base portion 41 (an example of a mounting portion), an intermediate portion 43, and a tip portion 42 (an example of an electrode connection portion). The base portion 41 is attached to the sealing plate 12 while connected to each external terminal 25, 26. The intermediate portion 43 is provided continuously with the base portion 41. The tip portion 42 is provided continuously with the intermediate portion 43 and the terminal connection portions 21, 22 of the electrode body 20 are joined to it. In this embodiment, the tip portion 42 is formed in a U-shape in cross-section when viewed in the Z-axis direction by a surface portion 42a in the Y-axis direction and two surface portions 42b in the X-axis direction.

[0030] Each current collector terminal 30, 31 has a metal plate as an intermediate portion 43 between a base portion 41 and a tip portion 42. In this embodiment, the intermediate portion 43 is composed of two plate portions 43a and 43b. The first plate portion 43a is connected to the base portion 41, and the second plate portion 43b is connected to the tip portion 42. In this embodiment, the intermediate portion 43 is bent at one point to form a first hinge portion A. Although not shown, the intermediate portion 43 may be bent at multiple points. In this embodiment, a second hinge portion B is formed at the connection point between the first plate portion 43a and the base portion 41, and a third hinge portion C is formed at the connection point between the second plate portion 43b and the tip portion 42. In this embodiment, the first hinge portion A is formed to be convex in the direction away from the electrode body 20. That is, the intermediate portion 43 made of a metal plate constitutes a bent portion R by the first hinge portion A being convex in the direction away from the electrode body 20. Furthermore, the hinge portions A, B, and C of the current collection terminals 30 and 31 may have thinner plates than other parts, as long as sufficient cross-sectional area is secured to reduce electrical resistance, so that they are more easily bent.

[0031] Figure 3 shows the electrode body 20, which is integrated with the sealing plate 12 via the battery terminals PS and NS, before it is housed inside the case body 11. Figure 4 shows the electrode body 20, which is integrated with the sealing plate 12 via the battery terminals PS and NS, after it has been housed inside the case body 11.

[0032] As shown in Figure 3, before the electrode body 20 is housed inside the case body 11, the angle formed between the first plate portion 43a and the second plate portion 43b of the intermediate portion 43 is large, and the degree of bending of the first hinge portion A is small. On the other hand, as shown in Figure 4, when the electrode body 20 is housed inside the case body 11, the electrode body 20 moves in a direction approaching the sealing plate 12. Accordingly, the hinge portions A, B, and C of the positive electrode current collector terminal 30 bend, and the first hinge portion A of the intermediate portion 43 moves towards the X2 side in the X-axis direction. Similarly, the hinge portions A, B, and C of the negative electrode current collector terminal 31 also bend, and the first hinge portion A of the intermediate portion 43 moves towards the X1 side in the X-axis direction. In other words, the intermediate portion 43 of each current collection terminal 30, 31 has a smaller angle formed between the first plate portion 43a and the second plate portion 43b compared to before the electrode body 20 of the case body 11 was housed inside the case body 11, resulting in a larger degree of bending of the first hinge portion A, and the first hinge portion A moving away from the electrode body 20. In this embodiment, when the electrode body 20 is housed inside the case body 11 (in other words, when the secondary battery 1 becomes a product), the first hinge portion A of the intermediate portion 43 is in contact with the insulating member 51 covering the inner surfaces 11a and 11b of the case body 11, but it is not necessarily required that the first hinge portion A be in contact with the insulating member 51.

[0033] In this embodiment, the plate portions 43a and 43b that constitute the intermediate portion 43 of the current collection terminals 30 and 31 are wide rectangular in shape. This allows the current collection terminals 30 and 31 to secure a cross-sectional area and reduce electrical resistance. Furthermore, because the plate portions 43a and 43b that constitute the intermediate portion 43 of the current collection terminals 30 and 31 are thin plates, the second moment of area is reduced, making them easier to bend around the first hinge portion A. In addition, since the first hinge portion A, which is located in the center of the intermediate portion 43 in the initial state, is oriented toward the side away from the electrode body 20, the first hinge portion A of the current collection terminals 30 and 31 becomes easier to bend.

[0034] Thus, according to the secondary battery 1 of this embodiment, the bent portion R (intermediate portion 43) is maintained in a state of being bent in a direction away from the electrode body 20 (towards X1 and X2). Therefore, it is not necessary to ensure high dimensional accuracy to avoid contact between the battery terminals PS, NS (specifically, the positive electrode current collector terminal 30 and the negative electrode current collector terminal 31) and the electrode body 20, or to take measures such as placing an insulating member between the battery terminals PS, NS (specifically, the positive electrode current collector terminal 30 and the negative electrode current collector terminal 31) and the electrode body 20, that is, insulation between the battery terminals and the electrode body can be ensured while keeping costs down.

[0035] [Second Embodiment] A second embodiment will be described with reference to Figure 5. In the second embodiment, the configuration of the current collector terminals 30 and 31 differs from that of the first embodiment. Below, the configuration that differs from that of the first embodiment will be described, and similar configurations will be denoted by the same reference numerals and detailed descriptions will be omitted. As shown in Figure 5, in the second embodiment as well, an insulating member 51 is covered on the inner surface 11a of the case body 11 that faces the intermediate portion 43 of the negative electrode current collector terminal 31. Furthermore, a stopper member 52 is attached to the first plate portion 43a of the intermediate portion 43, which contacts the insulating member 51 when the electrode body 20 moves in the direction approaching the sealing plate 12. Although not shown, the secondary battery 1 also has a similar configuration on the positive electrode current collector terminal 30 side.

[0036] A stopper member 52 is provided on the first plate portion 43a of the intermediate portion 43, and the insulating member 51 on the inner surface 11a of the case is configured to come into contact with the stopper member 52, thereby generating frictional force between the stopper member 52 and the insulating member 51. This reduces the input from the tip portion 42 to the terminal connection portion 22(21) when the internal components of the case body 11 vibrate. In this embodiment, it is preferable to use a material for the stopper member 52 that generates an appropriate frictional force between it and the insulating member 51.

[0037] [Third Embodiment] A third embodiment will be described with reference to Figure 6. In the third embodiment, the configuration of the current collection terminals 30 and 31 differs from that of the above embodiments. Below, the configurations that differ from those of the above embodiments will be described, and similar configurations will be denoted by the same reference numerals and detailed descriptions will be omitted. As shown in Figure 6, in the third embodiment, a conductive member 53 is provided on the surface of the insulating member 51 that covers the inner surface 11a of the case body 11.

[0038] The negative electrode current collector terminal 31 has a pair of conductive stopper members 54, 55 (a first stopper member 54 and a second stopper member 55). The pair of stopper members 54, 55 are joined to the negative electrode current collector terminal 31 by welding or the like, ensuring electrical connection. In this embodiment, the first stopper member 54 is joined to the second plate portion 43b of the intermediate portion 43, and the second stopper member 55 is joined to the first plate portion 43a of the intermediate portion 43. In other words, the pair of stopper members 54, 55 are joined on both sides of the first hinge portion A. The material of the pair of stopper members 54, 55 is not particularly limited as long as it is conductive, but considering the ease of joining to the negative electrode current collector terminal 31, it is preferable that it be made of the same material as the negative electrode current collector terminal 31. The pair of stopper members 54, 55 contact the conductive member 53 when the electrode body 20 moves in the direction approaching the sealing plate 12. Although not shown in the diagram, the secondary battery 1 has a similar configuration on the side of the positive electrode current collector terminal 30.

[0039] In this way, a conductive member 53 is provided on the inner surface 11a of the case body 11, and a pair of conductive stopper members 54 and 55 are provided on the current collection terminal 31(30). By bringing the pair of stopper members 54 and 55 into contact with the conductive member 53, current can be conducted through the current collection terminal 31(30) in the order of the first stopper member 54, the conductive member 53, and the second stopper member 55. Thus, electrical resistance can be reduced. In particular, in this embodiment, a pair of stopper members 54 and 55 are provided on both sides of the first hinge portion A. This makes it possible to ensure a conductive path that bypasses the first hinge portion A, even if, for example, the plate thickness of the first hinge portion A is made thinner to make it easier to bend than other parts, and the cross-sectional area of ​​the current collection terminal 31(30) is reduced at the first hinge portion A.

[0040] [Fourth Embodiment] A fourth embodiment will be described with reference to Figures 7 and 8. In the fourth embodiment, the configuration of the current collector terminals 30 and 31 differs from that of the above embodiments. Below, the configurations that differ from those of the above embodiments will be described, and similar configurations will be denoted by the same reference numerals and detailed descriptions will be omitted. As shown in Figures 7 and 8, in the fourth embodiment, the current collector terminals 30 and 31 have a leaf spring as an intermediate portion 44 between the base portion 41 and the tip portion 42. In this embodiment, the intermediate portion 44, which is made of a leaf spring, forms a bent portion R by being convex in the direction away from the electrode body 20.

[0041] Figure 7 shows the electrode body 20, which is integrated with the sealing plate 12 via the battery terminals PS and NS, before it is housed inside the case body 11. Figure 8 shows the electrode body 20, which is integrated with the sealing plate 12 via the battery terminals PS and NS, after it has been housed inside the case body 11.

[0042] As shown in Figure 7, before the electrode body 20 is housed inside the case body 11, the intermediate portion 44, which is made of a leaf spring, is gently curved away from the electrode body 20. On the other hand, as shown in Figure 8, once the electrode body 20 is housed inside the case body 11, the electrode body 20 and the sealing plate 12 come closer together. Consequently, the intermediate portion 44 of the positive electrode current collector terminal 30 curves significantly towards the X2 side in the X-axis direction, and the intermediate portion 44 of the negative electrode current collector terminal 31 curves significantly towards the X1 side in the X-axis direction. In other words, the curvature of the intermediate portion 44 increases and the degree of bending increases compared to before the electrode body 20 was housed inside the case body 11, and the entire intermediate portion 44 moves away from the electrode body 20.

[0043] According to this embodiment, a bent portion R can be formed in the intermediate portion 44 by the spring characteristics of the leaf spring, so a bent portion R (intermediate portion 44) that separates from the electrode body 20 when the electrode body 20 moves in the direction approaching the sealing plate 12 can be easily constructed.

[0044] [Another embodiment] [1] In the above embodiment, a configuration in which the secondary battery 1 comprises one electrode body 20 has been described, but the secondary battery 1 is not limited to this configuration. The secondary battery 1 may also comprise multiple electrode bodies 20. When the secondary battery 1 comprises multiple electrode bodies 20, it is preferable to enlarge the contact surface of each current collection terminal 30, 31 and to connect the terminal connection portions 21, 22 of the multiple electrode bodies 20, 20 to the same contact surface. In this way, the number of electrode bodies that can be connected to the current collection terminals can be increased simply by enlarging the contact surface without increasing the number of parts, making it easier to increase the battery capacity.

[0045] [2] In the above embodiment, an embodiment in which the electrode body 20 is a wound body has been described, but the embodiment is not limited to this. The electrode body may be a laminate in which a positive electrode plate and a negative electrode plate are stacked with a separator in between.

[0046] [3] In the above embodiment, an embodiment has been described in which the insulating member 51 is covered on the inner surfaces 11a and 11b of the case body 11, but the embodiment is not limited to this. The size of the insulating film that insulates the electrode body 20 from the case body 11 may be changed, and the insulating film may be positioned between the inner surfaces 11a and 11b of the case body 11 and the current collection terminals 30 and 31 to ensure insulation between the case body 11 and the current collection terminals 30 and 31.

[0047] [4] In the above embodiment, an embodiment was described in which the intermediate portion 43 (metal plate) is bent at one place to form a single first hinge portion A, but the embodiment is not limited to this. The metal plate may be bent at multiple places to form multiple hinge portions, in which case the bent portion is formed by one of the multiple hinge portions being convex in a direction away from the electrode body.

[0048] Furthermore, the configurations disclosed in the above embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. Moreover, the embodiments disclosed herein are illustrative, and the embodiments of the present invention are not limited thereto, and can be modified as appropriate without departing from the object of the present invention. [Explanation of Symbols]

[0049] 1: Secondary battery 11: Case body (enclosure) 11a, 11b: Inner surface 12: Sealing plate (lid body) 20: Electrode body 21,22: Terminal connection section 25,26: External terminals 30,31: Current collector terminal 41: Base (mounting part) 42: Tip (electrode connection part) 43: Intermediate section (metal plate) 44: Intermediate section (leaf spring) 51: Insulating material 52: Stopper component 53: Conductive material 54: First stopper member (one of a pair of stopper members) 55: Second stopper member (the other of the pair of stopper members) A: First hinge section R: Bent part NS,PS:Battery terminal

Claims

1. A secondary battery comprising a housing having an opening, a lid attached to the opening of the housing, a flat electrode body formed by stacking a positive electrode plate and a negative electrode plate with a separator in between, and battery terminals attached to the lid, The electrode body is Housed within the aforementioned enclosure, Terminal connection portions are provided at both ends of a second direction perpendicular to the first direction, which is the thickness direction of the electrode body. The aforementioned battery terminals are, A mounting portion attached to the lid, The electrode connection portion is joined to the terminal connection portion, Between the mounting portion and the electrode connection portion, there is a bent portion that is convex in the direction away from the electrode body in the second direction, A secondary battery wherein the distance between the bent portion and the electrode body in the second direction changes as the electrode body moves along a third direction perpendicular to both the first and second directions, and the bent portion moves away from the electrode body as the electrode body moves in a direction toward the cover.

2. The battery terminal has a metal plate between the mounting portion and the electrode connection portion. The aforementioned metal plate is bent at one or more points to form one or more hinge portions. The secondary battery according to claim 1, wherein the bent portion is configured such that one of the hinge portions is convex in a direction away from the electrode body.

3. The battery terminal has a leaf spring between the mounting portion and the electrode connection portion. The secondary battery according to claim 1, wherein the bent portion is configured such that the leaf spring is convex in a direction away from the electrode body.

4. An insulating material is covered on the inner surface of the housing that faces the bent portion of the battery terminal. The secondary battery according to claim 1 or 2, wherein a stopper member is attached to the bent portion, which contacts the insulating member when the electrode body moves in a direction approaching the cover body.

5. A conductive member is provided on the surface of the insulating member that covers the inner surface of the housing, The secondary battery according to claim 4, wherein it has a pair of the stopper members, and the stopper members are conductive.

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