JP5924522B2 - Power storage element, power storage element group - Google Patents

Description

  The present invention relates to a structure around an electrode terminal of a power storage element.

  Conventionally, power storage elements such as secondary batteries have been used. When the storage element is mounted and used in a device such as an electric vehicle, a plurality of storage elements are connected to each other by a connection plate called a bus bar according to the specification of the device to achieve a desired standard. As a method for connecting the bus bar to the electrode terminal of the storage element, conventionally, a screw fastening connection method for fastening the bus bar and the electrode terminal with screws, a welding connection method for welding the bus bar to the welding surface of the electrode terminal, and the like have been used. (For example, Patent Document 1).

JP 2003-346774 A

  In a storage element, when a temperature change occurs due to charging or discharging or a change in the surrounding environment, the connection between the electrode terminal and the bus bar may be distorted due to the difference in the thermal capacity or thermal expansion coefficient of each component such as the electrode terminal and the bus bar. was there. In particular, in the welding connection method, since the bus bar is heated at the time of welding, distortion may remain in the connection portion after the welding due to a decrease in the temperature of the bus bar, and the connection portion is likely to be distorted. When distortion occurs in the connecting portion and distortion occurs in the direction along the welding surface of the electrode terminal, the welding is detached due to vibration of the device or the like, resulting in poor connection between the power storage element and the bus bar. However, in the prior art, the above problem caused by the distortion of the connection portion has not been sufficiently studied.

  An object of the present invention is to provide a technique for suppressing a connection failure between a power storage element and a bus bar.

  The power storage element of the present invention is a power storage element that is welded to a bus bar to form a power storage element group, and is electrically connected to the power generation element, an exterior container that houses the power generation element, and the power generation element. A fixed terminal fixed to the outer container, and a movable terminal that contacts and is electrically connected to the fixed terminal and has a welded portion that is welded to the bus bar, and is displaceable with respect to the fixed terminal. .

  In this power storage element, since the movable terminal is configured to be displaceable with respect to the fixed terminal, the movable terminal is affected by distortion due to temperature change due to charging or discharging or changes in the surrounding environment, and residual strain due to heating of the bus bar during welding. Even when distortion occurs, the distortion can be absorbed by the displacement of the movable terminal with respect to the fixed terminal, and poor connection between the power storage element and the bus bar can be suppressed.

  The power storage element may be configured such that the movable terminal can be displaced in a second direction orthogonal to a first direction from the movable terminal toward the fixed terminal. According to this power storage element, even when the movable terminal is distorted in the second direction, the distortion can be absorbed by displacing the movable terminal in the second direction with respect to the fixed terminal. Connection failure can be suppressed.

  In the power storage element, the movable terminal may be configured to be held via at least one of a gap and an elastic body in the second direction. According to this power storage element, even when a strain in the second direction occurs in the movable terminal, the strain can be absorbed by the elastic deformation of the gap and the elastic body, and the connection between the power storage element and the bus bar is poor. Can be suppressed.

  The power storage element may include a terminal cover that is fixed to the outer container and includes a portion that contacts the movable terminal from a side opposite to the fixed terminal. According to this power storage element, the terminal cover is deformed in the direction opposite to the first direction by contact with the movable terminal, and the movable terminal can be biased in the direction toward the fixed terminal by an elastic force according to the deformation amount. .

  In the power storage element, a terminal cover that is fixed to the exterior container and covers at least a part of the movable terminal from a side opposite to the fixed terminal, and is disposed between the movable terminal and the terminal cover, and is movable. A biasing member that biases the terminal and the terminal cover may be provided. According to this power storage element, the urging member urges the movable terminal in the first direction, so that the movable terminal can be urged in the direction toward the fixed terminal by the urging member.

  In the power storage element, the movable terminal may cover the entire surface of the fixed terminal in the first direction. According to this power storage element, since the movable terminal covers the entire surface of one of the fixed terminals, a relatively large contact area between the movable terminal and the fixed terminal can be secured, and the movable terminal and the fixed terminal can be secured. An increase in the generated connection resistance can be suppressed.

  The present invention is also embodied in a power storage element group using the above power storage elements. The power storage element group of the present invention is formed by welding a plurality of the power storage elements to the bus bar. According to this power storage element group, even when distortion occurs due to temperature changes due to charging or discharging or changes in the surrounding environment, and heating of the bus bar during welding, the distortion is caused by displacement of the movable terminal relative to the fixed terminal. Can be absorbed, and poor connection between the power storage element and the bus bar can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the connection failure between an electrical storage element and a bus bar can be suppressed.

Perspective view of battery pack Single cell development Sectional drawing of the electrode unit of 1st Embodiment Exploded view of the electrode unit of the first embodiment Sectional drawing of the electrode unit of 2nd Embodiment Development view of electrode unit of second embodiment

<Embodiment 1>
Hereinafter, Embodiment 1 will be described with reference to FIGS.
1. Configuration of the assembled battery FIG. 1 is a perspective view of the assembled battery 12 in the present embodiment. The assembled battery 12 of the present embodiment is mounted on, for example, an electric vehicle or a hybrid vehicle, and supplies power to a power source that operates with electric energy. The assembled battery 12 is an example of a power storage element group.

  As shown in FIG. 1, the assembled battery 12 has a plurality of single cells 14 arranged in a line. Each unit cell 14 is provided with a pair of positive terminal 22 and negative terminal 24 that are different from each other. Each unit cell 14 is arranged so that the polarities of the electrode terminals 22 and 24 of the adjacent unit cells 14 are alternately reversed. In the assembled battery 12, different electrode terminals 22 and 24 of adjacent unit cells 14 are connected in series by a bus bar 16 that is a conductive plate member. The unit cell 14 is an example of a power storage element.

  In each unit cell 14, electrode terminals 22 and 24 project. A planar welding surface 26 is provided on the surface of the electrode terminals 22, 24, and is welded to the bus bar 16 via the welding surface 26. The welding surface 26 is an example of a welding part.

2. Next, the configuration of the unit cell 14 will be described. The single battery of this embodiment is a secondary battery that can be repeatedly charged and discharged, and more specifically, a lithium ion battery. As shown in FIG. 2, the unit cell 14 includes an electrode unit 20, a power generation element 50, a clip 60, and a case 62.

  The case 62 has a square shape and is configured as an upwardly open type whose upper end is open. The case 62 houses a power generation element 50 having a flat shape and is filled with an electrolytic solution. The upper end opening of the case 62 is closed by a lid body 64 that is a rectangular plate member constituting the electrode unit 20. The case 62 and the lid 64 are an example of an exterior container.

  The power generation element 50 is configured to be wound in a flat shape with a separator (not shown) sandwiched between the positive electrode plate 52 and the negative electrode plate 54. The positive electrode plate 52 and the negative electrode plate 54 each have a strip shape in which the winding direction is the longitudinal direction in the unwound state. The positive electrode plate 52 has a positive electrode active material layer formed on the surface of an aluminum foil having a band shape, and the aluminum foil is exposed at one edge extending in the longitudinal direction without forming the positive electrode active material layer. A positive electrode current collector foil 52A is formed. The negative electrode plate has a negative electrode active material layer formed on the surface of a strip-like copper foil, and the negative electrode active material layer is not formed on one edge extending in the longitudinal direction of the copper foil. An exposed negative electrode current collector foil 54A is formed.

  In the positive electrode plate 52 and the negative electrode plate 54, the negative electrode current collector foil 54 </ b> A is disposed on one end side with respect to the separator and the negative electrode plate 54, and the negative electrode current collector foil 54 </ b> A is disposed on the other end side with respect to the separator and positive electrode plate 52. It is rolled up in layers. Accordingly, only the positive electrode current collector foil 52A is laminated and protruded on one end side in the width direction of the power generation element 50, and only the negative electrode current collector foil 54A is laminated and protruded on the other end side. .

  Each of the positive electrode current collector foil 52A and the negative electrode current collector foil 54A is wound in a flat shape in the vertical direction, and a side portion that extends linearly in the vertical direction is a positive electrode current collector 28A or a negative electrode current collector described later. It is set as the connection part 56 connected to 28B. A positive electrode current collector 28A connected to the positive electrode terminal 22 is connected to the connection portion 56A of the positive electrode current collector foil 52A, and a negative electrode current collector connected to the negative electrode terminal 24 is connected to the connection portion 56B of the negative electrode current collector foil 54A. The body 28B is connected. Each of the current collectors 28A and 28B is made of a metal plate having a sufficient thickness so as to obtain a large current capacity. The positive electrode current collector 28A is made of, for example, an aluminum alloy plate, and the negative electrode current collector 28B is For example, it consists of a copper plate alloy plate.

  The current collectors 28A, 28B and the current collector foils 52A, 54A are electrically connected by ultrasonic welding while being sandwiched between the clips 60. The clip 60 is made of a material having a resistance value equivalent to the material of the current collectors 28A and 28B and the current collector foils 52A and 54A to be welded, the positive clip 60A is made of an aluminum alloy, and the negative clip 60B is Made of copper alloy.

(Configuration of electrode unit)
FIG. 3 is a cross-sectional view of the electrode unit 20 taken along the line III-III in FIG. FIG. 3 representatively shows a cross-sectional view of the negative electrode terminal 24 of the electrode unit 20, and a cross-sectional view of the positive electrode terminal 22 having the same structure is omitted.

  As shown in FIG. 3, the electrode unit 20 includes a movable terminal 30, a terminal cover 32, a rivet terminal 36, an upper packing 38, a lid body 64, a lower packing 40, and a current collector 28. . In FIG. 4, the perspective view of each member which comprises the electrode unit 20 before assembling as the electrode unit 20 is shown.

  As shown in FIG. 4, the lid body 64 is formed with a convex portion 66 protruding to the front surface side at a position where the electrode terminals 22 and 24 are formed. At the center of the convex portion 66, a through hole 66A through which the connecting portion 36B of the rivet terminal 36 is inserted is formed. Around each convex portion 66, four connection pins 68 projecting toward the surface side are provided integrally with the lid body 64. When assembling the electrode unit 20, the connection pin 68 is crushed after being inserted into the connection hole 32 </ b> A provided in the terminal cover 32 from the back side (see FIG. 3). As a result, the terminal cover 32 is fixed to the lid body 64. The back side is an example of the first direction.

  A non-restorable safety valve 70 is provided at the center of the lid 64. In the unit cell 14, the safety valve 70 is formed, so that the case 62 and the lid 64 are prevented from being damaged even when the electrolyte contained in the unit cell 14 is expanded by heating or the like. It is possible to suppress the fragments generated by the breakage of the lid body 64 from being scattered around the unit cell 14.

  The lower packing 40 is insulative and has a convex shape with a central portion 40A protruding to the surface side. The lower packing 40 is formed so as to be insertable into the convex portion 66 from the back surface side of the lid body 64, and a through hole 40B through which the connecting portion 36B of the rivet terminal 36 is inserted is formed at the center of the central portion 40A. ing.

  The current collector 28 is formed from a single metal plate and has a surface portion 42A and a connection portion 42B. As described above, the connecting portion 42B is connected to the connecting portion 56 of the current collector foils 52A and 54A. 42 A of surface parts are formed so that insertion to the center part 40A is possible from the back surface side of the lower packing 40, and the through-hole 42C in which the connection part 36B of the rivet terminal 36 is penetrated is formed in the center. When assembling the electrode unit 20, the current collector 28 is inserted into the convex portion 66 from the back surface side of the lid 64 through the lower packing 40.

  The upper packing 38 is insulative and has a substantially H-shaped cross section as shown in FIG. In the upper packing 38, a through hole 38B through which the connecting portion 36B of the rivet terminal 36 is inserted is formed at the center of the central flat portion 38A, and an inner wall 38C is formed around the through hole 38B. As shown in FIG. 3, the inner wall 38 </ b> C is inserted through the through hole 66 </ b> A of the lid body 64 and the through hole 40 </ b> B of the lower packing 40. In addition, a front side outer wall 38D and a back side outer wall 38E formed over the front side and the back side of the flat part 38A are formed around the flat part 38A. A back side space is formed by the back side outer wall 38E and the flat portion 38A formed on the back side, and the convex portion 66 of the lid body 64 is inserted into this back side space. Further, a surface side space is formed by the surface side outer wall 38D and the flat portion 38A formed on the surface side, and the rivet terminal 36 is inserted into this surface side space.

  The rivet terminal 36 has conductivity and has a surface portion 36A and a connection portion 36B. 36 A of surface parts are formed so that insertion from the surface side of the upper packing 38 to surface side space is possible. The connecting portion 36B has a cylindrical shape and extends from the front surface portion 36A to the back surface side. When assembling the electrode unit 20, the connecting portion 36 </ b> B is inserted from the surface side into each through hole formed in the upper packing 38, the lid body 64, the lower packing 40, and the current collector 28, and then the tip of the connecting portion 36 </ b> B is inserted. It is crushed (see FIG. 3). As a result, the rivet terminal 36 contacts and is electrically connected to the current collector 28, and the rivet terminal 36, the upper packing 38, the lower packing 40, and the corner members of the current collector 28 are fixed to the lid 64. . That is, the terminal cover 32, the rivet terminal 36, and the current collector 28 are fixed to the lid body 64, and the terminal cover 32 is fixed to the rivet terminal 36 and the current collector 28. The current collector 28 and the rivet terminal 36 are examples of fixed terminals.

  The movable terminal 30 has conductivity, and a welding surface 26 is formed on the surface thereof. The surface portion 30A of the movable terminal 30 on which the welding surface 26 is formed is narrower than the back surface portion 30B, and a step portion 30C is formed around the surface portion 30A due to the difference in area between the surface portion 30A and the back surface portion 30B. Is formed. The movable terminal 30 is placed on the surface portion 36A of the rivet terminal 36 via conductive grease (not shown), and is electrically connected to the rivet terminal 36. As shown in FIG. 3, the area of the back surface portion 30 </ b> B of the movable terminal 30 is substantially equal to the area of the front surface portion 36 </ b> A of the rivet terminal 36. That is, the movable terminal 30 covers the entire surface portion 36 </ b> A of the rivet terminal 36.

  The terminal cover 32 is a resin member having an insulating property, and a central portion 44A has a convex shape protruding to the surface side, and a peripheral portion 44B having a connection hole 32A is formed on both sides of the central portion 44A. Is formed. A through hole 32B through which the surface portion 30A of the movable terminal 30 is inserted is formed at the center of the central portion 44A, and a frame portion 32C is formed by the central portion 44A remaining around the through hole 32B. That is, the welding surface 26 is formed by the surface of the surface portion 30 </ b> A of the movable terminal 30 that is inserted through the through hole 32 </ b> B of the terminal cover 32 and protrudes to the surface side of the frame portion 32 </ b> C.

  A side wall 32D is formed around the central portion 44A, and a back side space is formed by the side wall 32D and the central portion 44A. When assembling the electrode unit 20, the terminal cover 32 is fixed to the lid body 64 with the movable terminal 30, the rivet terminal 36, the upper packing 38, and the like inserted in the space on the back surface side.

  At this time, as shown in FIG. 3, the frame portion 32 </ b> C of the terminal cover 32 abuts on the stepped portion 30 </ b> C of the movable terminal 30 from the surface side and is deformed to the surface side. As a result, an elastic force corresponding to the amount of deformation is generated in the frame portion 32C, and the movable terminal 30 is urged toward the back surface side. As a result, the movable terminal 30 is held by the terminal cover 32.

  As shown in FIG. 3, in the assembled electrode unit 20, a gap indicated by an arrow 46 is provided in the surface portion 30 </ b> A of the movable terminal 30 and the frame portion 32 </ b> C of the terminal cover 32 in the horizontal direction. Further, a gap indicated by an arrow 48 is provided on the back surface portion 30 </ b> B of the movable terminal 30 and the front side outer wall 38 </ b> D of the upper packing 38. Therefore, the movable terminal 30 is configured to be displaceable in the horizontal direction within a gap indicated by arrows 46 and 48 with respect to the rivet terminal 36 in a state where the movable terminal 30 is urged toward the back side by the elastic force of the terminal cover 32. Yes. The horizontal direction is an example of the second direction.

  When the movable terminal 30 is displaced in the horizontal direction, conductive grease is applied between the movable terminal 30 and the rivet terminal 36 that abuts on the back surface side, and the displacement of the movable terminal 30 in the horizontal direction is not suppressed. Further, since the contact area between the frame portion 32 </ b> C of the terminal cover 32 that abuts on the front surface side is relatively small, the step portion between the frame portion 32 </ b> C of the terminal cover 32 and the movable terminal 30 according to the displacement of the movable terminal 30. 30C slides in the horizontal direction, and displacement of the movable terminal 30 in the horizontal direction is allowed. Therefore, as shown in FIG. 3, the bus bar 16 welded to the welding surface 26 of the movable terminal 30 has an arrow due to distortion due to temperature change due to charging / discharging or changes in the surrounding environment, residual distortion due to heating of the bus bar during welding, and the like. Even when displaced in the horizontal direction indicated by 72, the movable terminal 30 can be displaced in the horizontal direction along the surface of the rivet terminal 36 as indicated by an arrow 76 with respect to the rivet terminal 36.

  When the movable terminal 30 is displaced in the horizontal direction across the gaps indicated by arrows 46 and 48 and the movable terminal 30 comes into contact with the terminal cover 32 or the upper packing 38, the surfaces of the terminal cover 32 and the upper packing 38 are used. The side outer wall 38D is elastically deformed somewhat in the horizontal direction, so that the movable terminal 30 is allowed to be further displaced in the horizontal direction. In addition, as a material of the terminal cover 32, PPS (polyphenylene sulfide) resin etc. are used, for example, The thing to which the glass fiber etc. are not attached | subjected especially, and the elastomer are attached are preferable.

3. Advantages of the present embodiment (1) In the unit cell 14 of the present embodiment, in the electrode unit 20, a gap is provided between the movable terminal 30 and the terminal cover 32 in the horizontal direction and between the movable terminal 30 and the upper packing 38. The movable terminal 30 is configured to be displaceable in the horizontal direction with respect to the rivet terminal 36 within the range of the gap. According to the unit cell 14, even when horizontal distortion occurs in the movable terminal 30 due to distortion due to temperature change due to charge / discharge or changes in the surrounding environment, residual distortion due to heating of the bus bar 16 during welding, and the like. This distortion can be absorbed by the gap, and poor connection between the unit cell 14 and the bus bar 16 can be suppressed.

(2) In the unit cell 14 of the present embodiment, the movable terminal 30 is urged toward the back side by the elastic force generated by the deformation of the terminal cover 32, so that the terminal cover 32 is used as a member that covers the movable terminal 30, It can also be used as a member for urging the movable terminal 30, and the structure of the electrode unit 20 can be simplified.

(3) In the unit cell 14 of the present embodiment, the movable terminal 30 covers the entire surface portion 36A of the rivet terminal 36 connected to the current collector 28, so the contact areas of the movable terminal 30 and the rivet terminal 36 are compared. Therefore, it is possible to suppress an increase in the connection resistance generated between the movable terminal 30 and the rivet terminal 36.

(4) In the unit cell 14 of this embodiment, the frame portion 32 </ b> C of the terminal cover 32 that biases the movable terminal 30 toward the back surface side is disposed on the back surface side opposite to the bus bar 16 with respect to the welding surface 26. For this reason, when the movable terminal 30 and the bus bar 16 are welded via the welding surface 26, the terminal cover 32 does not interfere with the welding.

<Embodiment 2>
A second embodiment will be described with reference to FIGS. The assembled battery of the present embodiment is different from that of the first embodiment in the structure of the electrode unit 20 of the unit cell 14. In the following description, the same description as that of the first embodiment will not be repeated.

1. Configuration of Electrode Unit FIG. 5 is a sectional view of the electrode unit 20, and FIG. 6 is a perspective view of each member constituting the electrode unit 20 before being assembled as the electrode unit 20. In the electrode unit 20 of the present embodiment, in addition to the members included in the first embodiment, the spring 34 is placed between the stepped portion 30 </ b> C of the movable terminal 30 and the frame portion 32 </ b> C of the terminal cover 32. The spring 34 is an example of a biasing unit.

  An inner wall 32E is formed around the through hole 32B of the terminal cover 32. As shown in FIG. 3, the terminal cover 32 covers the movable terminal 30 from the surface side, but does not contact the movable terminal 30.

  The spring 34 is a metal elastic member, and is formed by bending a substantially square ring-shaped metal plate in the vertical direction, and has a predetermined thickness in the vertical direction by being bent. As shown in FIG. 3, the spring 34 is sandwiched between the stepped portion 30 </ b> C of the movable terminal 30 and the frame portion 32 </ b> C of the terminal cover 32 and is compressed in the vertical direction when the electrode unit 20 is assembled. As a result, an elastic force corresponding to the deformation amount is generated in the spring 34, and the terminal cover 32 is urged to the front surface side, and the movable terminal 30 is urged to the back surface side. As a result, the movable terminal 30 is held by the terminal cover 32 and the spring 34.

  The movable terminal 30 is configured to be displaceable in the horizontal direction within a gap range indicated by arrows 46 and 48 in a state where the movable terminal 30 is urged toward the back side by the elastic force of the spring 34. Since the contact area between the movable terminal 30 and the spring 34 is relatively small, the movable terminal 30 slides in the horizontal direction with respect to the spring 34 while being urged toward the back surface by the elastic force of the spring 34. Displacement in the horizontal direction is allowed. Therefore, as shown in FIG. 5, the bus bar 16 welded to the welding surface 26 of the movable terminal 30 has an arrow due to distortion due to temperature change due to charging / discharging and changes in the surrounding environment, residual distortion due to heating of the bus bar during welding, and the like. Even when displaced in the horizontal direction indicated by 82, the movable terminal 30 can be displaced in the horizontal direction along the surface of the rivet terminal 36 as indicated by an arrow 86 with respect to the rivet terminal 36.

  As the material of the spring 34, for example, phosphor bronze or stainless steel for springs is used, and as the material of the terminal cover 32, for example, PPS resin to which about 30% to 40% of glass fiber or the like is attached is used.

2. Effects of this Embodiment In the unit cell 14 of this embodiment, the movable terminal 30 is urged toward the back side by the elastic force of the spring 34 that is deformed when the electrode unit 20 is assembled. Since the spring 34 is separated from the terminal cover 32, the material of the terminal cover 32 and the spring 34 can be selected as appropriate. For example, the spring 34 is set to a predetermined position using the terminal cover 32 selected as appropriate. Can be maintained in position.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above embodiment, the unit cell 14 of the secondary battery is shown as an example of the power storage element. However, the present invention is not limited to this, and the power storage element may be a capacitor with an electrochemical phenomenon.

(2) In the above embodiment, the description has been given using an example in which the area of the back surface portion 30B of the movable terminal 30 is substantially equal to the area of the front surface portion 36A of the rivet terminal 36, but is not limited thereto. The area of the back surface portion 30 </ b> B of the movable terminal 30 may be formed to be slightly larger than the area of the front surface portion 36 </ b> A of the rivet terminal 36. Even in this case, the entire surface 36A of the rivet terminal 36 can be covered with the movable terminal 30, and an increase in the connection resistance generated between the movable terminal 30 and the rivet terminal 36 can be suppressed. Further, the area of the back surface portion 30 </ b> B of the movable terminal 30 may be formed slightly smaller than the area of the front surface portion 36 </ b> A of the rivet terminal 36.

(3) In the above embodiment, the description has been given using the example in which the movable terminal 30 and the current collector 28 are connected via the rivet terminal 36. However, the present invention is not limited to this, and the movable terminal 30 and the current collector 28 are directly connected. It may be connected. In this case, the connection resistance generated between the movable terminal 30 and the current collector 28 is increased by placing the back surface portion 30B of the movable terminal 30 so as to cover the entire surface portion 42A of the current collector 28. Can be suppressed.

(4) In the above embodiment, the description has been given using the example in which the movable terminal 30 is placed on the rivet terminal 36. However, the present invention is not limited to this, and an elastic member such as a spring is provided between the movable terminal 30 and the rivet terminal 36. The body may be placed. Since the elastic body is conductive, the movable terminal 30 and the rivet terminal 36 are electrically connected via the elastic body.

(5) In the said embodiment, it demonstrated using the example in which the connection pin 68 is inserted in the connection hole 32A provided in the terminal cover 32. FIG. In this case, the inner diameter of the connection hole 32 </ b> A may be formed substantially equal to the outer diameter of the connection pin 68, or the inner diameter of the connection hole 32 </ b> A may be formed larger than the outer diameter of the connection pin 68. Since the inner diameter of the connection hole 32A is formed to be larger than the outer diameter of the connection pin 68, distortion due to temperature change due to charging / discharging and changes in the surrounding environment, residual distortion due to heating of the bus bar 16 during welding, and the like occur. In this case, the terminal cover 32 can be displaced in the horizontal direction.

(6) In the above embodiment, the resin cover is used as the terminal cover 32. However, the material of the terminal cover 32 is not particularly limited. Similarly, a description has been given using a metal elastic member as the spring 34, but the material of the spring 34 is not particularly limited. Also, the shape is not limited. For example, when the surface portion 30A of the movable terminal 30 has a cylindrical shape, the spring 34 may have a circular shape accordingly.

12: assembled battery, 14: single cell, 16: bus bar, 20: electrode unit, 22: electrode terminal (positive electrode terminal, negative electrode terminal), 26: welding surface, 28: current collector, 30: movable terminal, 32: terminal Cover: 34: Spring, 36: Rivet terminal, 38: Upper packing, 40: Lower packing, 50: Power generation element, 60: Clip, 62: Case, 64: Lid

Claims (6)

A storage element that is welded to the bus bar to form a storage element group,
Power generation elements,
An outer container for housing the power generation element;
A fixed terminal electrically connected to the power generation element and fixed to the outer container;
A movable terminal having a welded portion to be welded to the bus bar;
Electrical connection between the movable terminal and the fixed terminal by urging the movable terminal to the fixed terminal side having a portion that is fixed to the outer container and that holds the movable terminal from the opposite side of the fixed terminal A terminal cover that holds the movable terminal so as to be displaceable with respect to the fixed terminal, while maintaining
A power storage device comprising: The power storage device according to claim 1,
The power storage element, wherein the movable terminal is displaceable in a direction along a surface facing the fixed terminal. The power storage device according to claim 2,
The electric storage element, wherein the movable terminal is held between the terminal cover and at least one of a gap and an elastic body in the displaceable direction . It is an electrical storage element as described in any one of Claim 1 thru | or 3, Comprising:
An urging member that is disposed between the movable terminal and the terminal cover and urges the movable terminal toward the fixed terminal;
A power storage device comprising: It is an electrical storage element as described in any one of Claim 1 thru | or 4, Comprising:
The said movable terminal is an electrical storage element which has covered the whole surface in the direction which goes to the said fixed terminal from the said movable terminal of the said fixed terminal .   A storage element group, wherein a plurality of the storage elements according to any one of claims 1 to 5 are welded to the bus bar.

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