JP6962236B2 - Power storage device - Google Patents

Description

The present disclosure relates to a power storage device.

Conventionally, various power storage devices have been proposed. For example, the power storage device described in Japanese Patent Application Laid-Open No. 2017-091989 includes a plurality of cylindrical batteries, a positive electrode bus bar, a negative electrode bus bar, and a connection bus bar.

The cylindrical battery includes a positive electrode formed at the upper end and a negative electrode formed at the lower end. The positive electrode busbar is located at the top of the cylindrical battery. The negative electrode bus bar is arranged at the lower end of the cylindrical battery. The connecting bus bar is connected to the positive electrode bus bar and the negative electrode bus bar.

A bent portion that bends upward is formed on the side side of the negative electrode bus bar. The lower end of the connecting bus bar is formed in a comb shape, and a plurality of teeth are formed at the lower end of the connecting bus bar. The end of the tooth portion of the connecting bus bar is joined to the bent portion of the negative electrode bus bar, and the connecting bus bar and the negative electrode bus bar are joined.

JP-A-2017-091989

In the above power storage device, it may be desired to check the joint state of the connected bus bar and the negative electrode bus bar. In that case, a method of confirming the joint state of the connecting bus bar and the negative electrode bus bar by pushing the bent portion of the negative electrode bus bar with a predetermined pressure while holding the connecting bus bar can be considered.

In the above power storage device, the bent portion of the negative electrode bus bar is bent upward, and the bent portion is located on the side surface of the accommodating case. Similarly, the tooth portion of the connecting bus bar and the portion located around the tooth portion are also located on the side surface of the housing case.

Therefore, when pressing the bent portion of the negative electrode bus bar exposed from the tooth portion, it is difficult to grip the connecting bus bar in the vicinity of the joint portion. Therefore, even if an attempt is made to press the bent portion exposed from the tooth portion, a load cannot be satisfactorily applied to the bent portion. As a result, there arises a problem that the bonding state of the negative electrode bus bar and the connecting bus bar cannot be confirmed accurately.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a power storage device capable of easily confirming the joint state of a bus bar and a connected bus bar.

The power storage device is arranged on one end side of a power storage cell including a first electrode formed at one end and a second electrode formed at the other end, a cover member covering the power storage cell, and on the first electrode. It includes a connected first bus bar, a second bus bar arranged on the other end side and connected to a second electrode, and a connecting bus bar connecting the first bus bar and the second bus bar.

The first bus bar includes a first joint piece, and the connecting bus bar includes a second joint piece joined to the first joint piece. One of the first joint piece and the second joint piece is formed with an exposed portion that exposes the other of the first joint piece and the second joint piece, and one joint piece is the first joint piece and the second joint piece. Includes the other joint piece of the second joint piece and the overhanging portion protruding from the cover member.

According to the above-mentioned power storage device, the joining state of the first joining piece and the second joining piece can be confirmed by pressing the joining piece exposed from the exposed portion while holding the overhanging portion. Further, the grip portion projects from the cover member, so that the overhanging portion can be easily gripped, and the work of inspecting the joint state can be easily performed.

According to the power storage device according to the present disclosure, the joint state of the bus bar and the connected bus bar can be easily confirmed.

It is an exploded perspective view which shows the power storage device 1. It is an exploded side view which shows the positive electrode bus bar unit 5, the negative electrode bus bar unit 6, and the connection bus bar unit 8. It is sectional drawing which shows the power storage device 1, and is the sectional view when the sectional view is taken at the position which passes through the connection bus bar 26C. It is sectional drawing which shows the joint piece 23C and the joint piece 31C. It is a rear view which shows the joint piece 23C and the joint piece 31C. FIG. 3 is a front view when the joint piece 31C and the joint piece 23C are viewed from the direction of arrow B in FIG. It is sectional drawing which shows the process of joining a joint piece 23C and the joint piece 31C. It is sectional drawing which shows the inspection process. It is a top view which shows the modification of the joint piece 23C and the joint piece 31C. It is sectional drawing which shows the process of inspecting the joint state of the joint piece 23C1 and the connection wiring 32C1.

The power storage device according to the present embodiment will be described with reference to FIGS. 1 to 10. Of the configurations shown in FIGS. 1 to 10, the same or substantially the same configuration is designated by the same reference numerals and duplicated description will be omitted.

FIG. 1 is an exploded perspective view showing the power storage device 1. The power storage device 1 includes a holder 2, a plurality of cylindrical batteries 3, a cover member 4, a positive electrode bus bar unit 5, a negative electrode bus bar unit 6, a bottom cover 7, and a connection bus bar unit 8.

The holder 2 is made of a metal material. The holder 2 is formed in the shape of a rectangular plate. A plurality of through holes 10 are formed in the holder 2. The through hole 10 is formed so as to penetrate from the upper surface to the lower surface of the holder 2.

The cylindrical battery 3 includes a positive electrode 11 and a negative electrode 12. The positive electrode 11 is formed at the upper end of the cylindrical battery 3, and the negative electrode 12 is formed at the lower end of the cylindrical battery 3. Each cylindrical battery 3 is inserted into the through hole 10. The upper end of the cylindrical battery 3 is arranged so as to protrude from the upper surface of the holder 2.

The cover member 4 is formed in a substantially rectangular parallelepiped shape, and is formed of, for example, a resin or the like. The cover member 4 is arranged on the upper surface of the holder 2, and the cover member 4 includes a top plate portion and a peripheral wall portion 13. In FIG. 1, the positive electrode bus bar unit 5 is arranged on the top plate portion of the cover member 4, and the top plate portion is not shown.

The peripheral wall portion 13 is formed so as to extend downward from the outer peripheral edge portion of the top plate portion. The peripheral wall portion 13 is formed in an annular shape along the outer peripheral edge portion of the top plate portion, and the cover member 4 is formed so as to open downward. The cover member 4 is provided so as to cover the cylindrical battery 3.

The cover member 4 is arranged on the upper surface of the holder 2, and the peripheral wall portion 13 is provided so as to cover the peripheral surface of the holder 2. The lower end of the peripheral wall portion 13 is arranged on the upper surface of the negative electrode bus bar unit 6, which will be described later.

The positive electrode bus bar unit 5 is arranged on the upper surface of the top plate portion of the cover member 4. The positive electrode bus bar unit 5 includes a plurality of positive electrode bus bars 14A, 14B, 14C, 14D. The positive electrode bus bars 14A, 14B, 14C, and 14D are sequentially arranged at intervals in the longitudinal direction of the cover member 4. A gap 15 is formed between the positive electrode bus bars 14A, 14B, 14C, and 14D. The positive electrode bus bars 14A, 14B, 14C, and 14D are made of copper or a copper alloy.

Each of the positive electrode bus bars 14A, 14B, 14C, 14D is provided with a plurality of connection wirings (not shown), and each connection wiring is connected to the positive electrode 11 of the cylindrical battery 3.

The negative electrode bus bar unit 6 is arranged on the lower surface side of the holder 2. The negative electrode bus bar unit 6 includes negative electrode bus bars 20B, 20C, 20D, 20E, a mold resin 21, and a plurality of connection wirings 24.

The negative electrode bus bars 20B, 20C, 20D, and 20E are arranged so as to be sequentially arranged at intervals in the longitudinal direction of the holder 2.

The negative electrode bus bars 20B, 20C, 20D, and 20E are integrally fixed to the mold resin 21, and the negative electrode bus bars 20B, 20C, 20D, and 20E are insulated from each other by the mold resin 21.

The negative electrode bus bar 20B includes a main body portion 22B and a joint piece 23B. The main body 22B is formed in a plate shape. The joining piece 23B is formed so as to extend downward from one side side of the main body portion 22B. Similarly, the negative electrode bus bars 20C, 20D, 20E include the main body portions 22C, 22D, 22E and the joining pieces 23C, 23D, 23E.

A plurality of through holes 25 are formed in the negative electrode bus bar unit 6. The connection wiring 24 is provided in each through hole 25. One end of the connection wiring 24 is connected to the lower surface of any one of the main bodies 22B, 22C, 22D, and 22E, and the other end of the connection wiring 24 is connected to the negative electrode 12 of the cylindrical battery 3.

The bottom cover 7 is arranged on the lower surface side of the negative electrode bus bar unit 6, and the bottom cover 7 is fixed to the holder 2.

The connecting bus bar unit 8 includes connecting bus bars 26B, 26C, 26D, 26E. Each connecting bus bar 26B, 26C, 26D, 26E is arranged on the side surface of the cover member 4. The connecting bus bar 26B connects the positive electrode bus bar 14B and the negative electrode bus bar 20B. Similarly, the connecting bus bars 26C and 26D connect the positive electrode bus bars 14C and 14D and the negative electrode bus bars 20C and 20D. The connecting bus bar 26E is connected to the negative electrode bus bar 20E.

FIG. 2 is an exploded side view showing the positive electrode bus bar unit 5, the negative electrode bus bar unit 6, and the connecting bus bar unit 8.

An end plate 27A is connected to the positive electrode bus bar 14A. The end plate 27A is also made of copper or a copper alloy. The end plate 27A is formed so as to extend downward along the end surface of the cover member 4. The end plate 27A is provided with an external terminal 28A. A cable connected to the other power storage device 1 is connected to the external terminal 28A.

The negative electrode bus bar 20B is arranged below the positive electrode bus bar 14A. The positive electrode bus bar 14B is arranged at a position adjacent to the positive electrode bus bar 14A in the longitudinal direction of the cover member 4.

The connecting bus bar 26B includes a main body portion 30B and a joining piece 31B. The main body 30B is formed so as to extend from the positive electrode bus bar 14B toward the negative electrode bus bar 20B. The upper end of the main body 30B is connected to the positive electrode bus bar 14B. The joining piece 31B is formed at the lower end of the main body 30B. The joining piece 31B is joined to the joining piece 23B.

The negative electrode bus bars 20C, 20D, 20E are located below the positive electrode bus bars 14B, 14C, 14D.

The connecting bus bars 26C, 26D, 26E include the main body portions 30C, 30D, 30E and the joining pieces 31C, 31D, 31E. The main body portions 30C and 30D are formed so as to extend from the positive electrode bus bars 14C and 14D toward the negative electrode bus bars 20C and 20D. The main body portion 30E is also arranged so as to be inclined in the same manner as the main body portions 30B, 30C, and 30D. The joining pieces 31C, 31D and 31E are joined to the joining pieces 23C, 23D and 23E.

An end plate 27E is connected to the connecting bus bar 26E, and the end plate 27E is arranged on the end surface of the cover member 4. The end plate 27E is provided with an external terminal 28E. A cable or the like connected to another power storage device 1 is connected to the external terminal 28E.

The connection state of each cylindrical battery 3 by the positive electrode bus bar unit 5 and the like will be described. Specifically, a plurality of cylindrical batteries 3 are connected in parallel by the positive electrode bus bar 14A and the negative electrode bus bar 20B. A plurality of cylindrical batteries 3 are connected in parallel by the positive electrode bus bar 14B and the negative electrode bus bar 20C.

Then, the plurality of cylindrical batteries 3 connected in parallel by the positive electrode bus bar 14A and the negative electrode bus bar 20B and the plurality of cylindrical batteries 3 connected in parallel by the positive electrode bus bar 14B and the negative electrode bus bar 20C are connected in series by the connecting bus bar 26B. Has been done.

Similarly, a plurality of cylindrical batteries 3 connected in parallel by the positive electrode bus bar 14B and the negative electrode bus bar 20C by the connecting bus bar 26C, and a plurality of cylindrical batteries 3 connected in parallel by the positive electrode bus bar 14C and the negative electrode bus bar 20D are connected in series. It is connected.

A plurality of cylindrical batteries 3 connected in parallel by the positive electrode bus bar 14C and the negative electrode bus bar 20D and a plurality of cylindrical batteries 3 connected in parallel by the positive electrode bus bar 14D and the negative electrode bus bar 20E are connected in series by the connecting bus bar 26D. There is.

FIG. 3 is a cross-sectional view showing the power storage device 1, and is a cross-sectional view when viewed in cross section at a position passing through the connecting bus bar 26C.

The peripheral wall portion 13 of the cover member 4 includes a side wall portion 35, a side wall portion 36, and a connecting portion 37. The side wall portion 35 extends downward from the outer peripheral edge portion of the top plate portion 34 of the cover member 4. The lower end of the side wall 35 is arranged on the upper surface of the holder 2.

The side wall portion 36 is provided so as to cover the peripheral surface of the holder 2. The lower end of the side wall 36 is located on the upper surface of the negative electrode bus bar unit 6. The connecting portion 37 connects the upper end portion of the side wall portion 36 and the side wall portion 35.

The joint piece 23C extends downward from the side side of the negative electrode bus bar unit 6 and projects downward from the cover member 4.

The joint piece 31C extends downward from the lower end portion of the side wall portion 36, and the joint piece 31C also extends downward from the cover member 4. The joint piece 31C is in contact with the outer surface of the joint piece 23C. FIG. 4 is a cross-sectional view showing a joint piece 23C and a joint piece 31C. A bonding layer 40C is formed at the interface between the bonding piece 23C and the bonding piece 31C. The bonding piece 23C and the bonding piece 31C are connected by the bonding layer 40C.

FIG. 5 is a rear view showing the joint piece 23C and the joint piece 31C. Specifically, in FIG. 3, it is a drawing when the joint piece 23C and the joint piece 31C are viewed from the direction of arrow A. FIG. 6 is a front view when the joint piece 31C and the joint piece 23C are viewed from the direction of arrow B in FIG. Exposed portions 41C and 42C are formed on the joint piece 23 at intervals. The exposed portions 41C and 42C are notches extending upward from the lower side of the joint piece 23C. Therefore, a part of the joint piece 31C is exposed by the exposed portions 41C and 42C.

In the longitudinal direction of the cover member 4, the length of the joint piece 23C is longer than the length of the joint piece 31C. Therefore, the joint piece 23C includes the overhanging portions 43C and 45C overhanging from the joint piece 31C. The overhanging portions 43C and 45C project below the lower end portion of the cover member 4.

A plurality of joining marks 46C are formed in a portion of the joining piece 31C that overlaps with the joining piece 23C. The joint mark 46C is a scratch extending in the longitudinal direction of the cover member 4.

The cross-sectional view taken along the line IV-IV shown in FIG. 5 is the cross-sectional view shown in FIG. There is.

Although the configurations of the joining pieces 23C and 31C have been described in detail, the joining pieces 23B and 31B, the joining pieces 23D and 31D, and the joining pieces 23E and 31E are also configured in the same manner as the joining pieces 23C and 31C.

Next, a step of joining the joining piece 23C and the joining piece 31C will be described. FIG. 7 is a cross-sectional view showing a step of joining the joining piece 23C and the joining piece 31C.

When joining the joining piece 31C and the joining piece 23C, the bottom cover 7 is not attached.

Then, the back surface of the joint piece 23C is supported by the support base 50. In that state, the horn 51 is pressed against the joining piece 31C. In that state, the horn 51 is vibrated to vibrate the joint piece 31C. For example, vibration of about 15 kHz or more and 60 kHz or less or about several hundred kHz is applied. The vibration direction of the horn 51 is the longitudinal direction of the cover member 4. By applying such vibration to the joint piece 31C, the joint layer 40C shown in FIG. 4 is formed at the boundary between the joint piece 23C and the joint piece 31C.

Here, the thickness of the joint piece 31C is thinner than the thickness of the joint piece 23C. The horn 51 is pressed against the thin joint piece 31C, and vibration is applied to the horn 51. As a result, the joint piece 31C, which is a thin plate, is easily deformed so as to be familiar with the joint piece 23C of the thick plate, and the joint piece 23C and the joint piece 31C can be satisfactorily joined.

In particular, in FIG. 6, the horn 51 is in contact with the joint piece 31C at the portion where the joint mark 46C is formed. The bonding marks 46C are formed at intervals, and at the time of ultrasonic bonding, the horn 51 and the bonding piece 31C are in contact with each other at a portion where the bonding marks 46C are formed.

If the horn 51 is brought into contact with substantially the entire surface of the joining piece 31C, the surface pressure between the horn 51 and the joining piece 31C tends to be small, and it becomes difficult to improve the joining between the joining piece 23C and the joining piece 31C. On the other hand, in the present embodiment, since the horn 51 and the joint piece 31C are brought into contact with each other at intervals, the surface pressure between the horn 51 and the joint piece 31C can be easily increased, and the joint piece 23C and the joint piece 31C can be easily increased. It is easy to join well.

As described above, in the present embodiment, the bonding piece 31C and the bonding piece 23C are ultrasonically bonded, and the bonding mark 46C shown in FIG. 5 is formed by vibrating the horn 51.

The step of inspecting the joining state of the joining piece 23C and the joining piece 31C joined as described above will be described.

FIG. 8 is a cross-sectional view showing an inspection process. As shown in FIG. 8, the pressing member 55 is used to inspect the joining state of the joining piece 23C and the joining piece 31C.

In FIG. 5, while the overhanging portion 43C and the overhanging portion 45C are gripped, the joint piece 31C exposed from the exposed portions 41C and 42C is pressed by the pressing member 55. Here, since the overhanging portion 43C and the overhanging portion 45C are thick, the joint piece 31C can be pressed while the overhanging portion 43C is firmly gripped.

Then, if the joining state of the joining piece 23C and the joining piece 31C is maintained even if the pressing member 55 is pressed with a predetermined load, it can be determined that the joining of the joining piece 23C and the joining piece 31C is good. can.

Since the overhanging portion 43C and the overhanging portion 45C are formed so as to overhang from the cover member 4 and the joint piece 31C, the overhanging portion 43C and the overhanging portion 45C can be satisfactorily gripped during the inspection process. ..

If the joint piece 23C is formed so as to extend upward from the side side of the negative electrode bus bar unit 6 and the joint piece 31C is arranged on the side surface of the cover member 4, the overhanging portions 43C and 45C It becomes difficult to grasp.

In the present embodiment, there is no member to support because the cover member 4 is pressed away from the cover member 4. Therefore, the joining state of the joining piece 23C and the joining piece 31C can be satisfactorily determined.

In the above embodiment, the exposed portions 41C and 42C are formed on the joint piece 26C of the connecting bus bar 31C, but the exposed portion may be formed on the joint piece 31C.

FIG. 9 is a plan view showing a modified example of the joining piece 23C and the joining piece 31C. In the example shown in FIG. 9, the length of the joining piece 31C1 is longer than the length of the joining piece 23C1, and the joining piece 31C1 is formed with an overhanging portion 58C and an overhanging portion 59C. Further, an exposed portion 56C and an exposed portion 57C are formed on the joint piece 31C1.

FIG. 10 is a cross-sectional view showing a step of inspecting the joining state of the joining piece 23C1 and the connecting wiring 32C1. As shown in FIG. 10, a pressing member 55 is arranged on the front side of the joining piece 31C1 to press the joining piece 23C1 exposed from the exposed portions 56C and 57C. At this time, the joint piece 23C1 is pressed while holding the overhanging portion 58C and the overhanging portion 59C. Since it is formed at a position away from the cover member 4, there is no member that supports the joint piece 23C1 from the back surface side. Therefore, the joining state of the joining piece 23C and the joining piece 31C can be satisfactorily determined. In this way, the joining state of the joining piece 31C1 and the joining piece 23C1 can be grasped.

In the above embodiment, the exposed portion is a notch portion, but a hole may be adopted as the exposed portion. Further, the bonding method is not limited to ultrasonic bonding, and various bonding methods can be adopted.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is indicated by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims. Furthermore, the above numerical values and the like are examples, and are not limited to the above numerical values and ranges.

1 power storage device, 2 holder, 3 cylindrical battery, 4 cover member, 5 positive electrode bus bar unit, 6 unit, 7 bottom cover, 8 connection bus bar unit, 10, 25 through hole, 11 positive electrode, 12 negative electrode, 13 peripheral wall, 14A, 14B, 14C, 14D Positive Busbar, 15 Voids, 20B, 20C, 20D, 20E Negative Busbar, 21 Mold Resin, 22B, 22C, 22D, 22E, 30B, 30C, 30D, 30E Main Body, 23B, 23C, 23C1, 23D , 23E, 31B, 31C, 31C1, 31D, 31E Joint piece, 24, 32C1 connection wiring, 26B, 26C, 26D, 26E connection bus bar, 27A, 27E end plate, 28A, 28E external terminal, 34 top plate, 35, 36 Side wall part, 37 connection part, 40C joint layer, 41C, 42C, 56C, 57C exposed part, 43C, 45C, 58C, 59C overhang part, 46C joint mark, 50 support base, 51 horn, 55 pressing member.

Claims (1)

A storage cell including a first electrode formed at one end and a second electrode formed at the other end.
A cover member that covers the power storage cell and
A first bus bar arranged on one end side and connected to the first electrode,
A second bus bar arranged on the other end side and connected to the second electrode,
A connecting bus bar connecting the first bus bar and the second bus bar,
With
The first bus bar includes a first junction piece.
The connecting bus bar includes a second joint piece joined to the first joint piece.
One of the first joint piece and the second joint piece is formed with an exposed portion that exposes the other of the first joint piece and the second joint piece.
The one joint piece is a power storage device including the first joint piece, the other joint piece of the second joint piece, and an overhanging portion protruding from the cover member.

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