JP2022029964A - Battery pack - Google Patents

Abstract

To solve the problem that it is difficult to assemble a battery pack in conventional configuration.SOLUTION: A battery pack comprises: a battery cell 10 in which a power body is accommodated; an electrode plate 11 which is attached to a lid of the battery cell 10 and caulked with a current collecting component within the battery cell; and a bus bar terminal welded to the electrode plate 11. The electrode plate 11 includes an inclined plane which is formed so as to separate from the lid of the battery cell as it is away from a position of caulking. The bus bar terminal includes: a composition plane 32a having such an inclination as to be close to the lid of the battery cell as it is close toward the position of the caulking; and base parts 33a and 33b which are formed continuously with one end of the composition plane 32a and transfer weighting in a direction toward the inclined plane to the composition plane 32a. When a surface constituting the lid of the battery cell 10 is defined as a horizontal surface, a first angle α which is an angle formed from the horizontal surface and the inclined plane is smaller than a second angle β which is an angle formed from the horizontal surface and the composition plane 32a.SELECTED DRAWING: Figure 4

Description

The present invention relates to, for example, an assembled battery used as a battery for driving a vehicle.

In a vehicle such as an automobile, an assembled battery in which a plurality of batteries are combined is used to supply electric power for driving. The assembled battery includes at least one battery stack in which a plurality of battery cells are stacked so as to be stacked and the stacked batteries are connected in series. Then, in the battery stack, the heights of the upper surfaces of the adjacent battery cells vary in the state where the battery cells are stacked. Therefore, Patent Document 1 discloses a technique for electrically connecting electrodes having such variations in height.

In the method for manufacturing an assembled battery described in Patent Document 1, a bus bar holder in which a plurality of holding portions holding a bus bar are connected in a chain by a thin-walled connecting portion is brought close to the electrode of the battery cell, and the electrode of each battery cell is formed. The connecting piece of each connecting portion is deformed according to the variation in height. Further, the bus bar of each holding portion is moved in the direction along the support plate within the range of the gap between the guide and the positioning pin, and further moved in the direction along the positioning pin between the support plate and the locking projection. The bus bar is moved to a position where the contact portion contacts the electrodes of two adjacent battery cells. Then, the contact portion of the bus bar arranged inside the opening of the two adjacent connecting portions comes into contact with and closely adheres to the electrodes of the two adjacent battery cells.

Japanese Unexamined Patent Publication No. 2019-160597

However, the bus bar connecting adjacent electrodes (hereinafter referred to as a bus bar terminal) is characterized in its small size. Since there may be a difference in height between adjacent electrodes, it is necessary to apply a load when welding to prevent welding defects due to the difference in height. Therefore, when welding the bus bar terminal, the place where the load is applied and the place where the welding is performed are almost the same place, so that there is a problem that the position accuracy of the place where the load is applied is required. However, Patent Document 1 does not solve the problem of the position accuracy of the place where the weight is applied.

The present invention has been made in view of the above circumstances, and an object of the present invention is to facilitate the assembly of an assembled battery.

One aspect of the assembled battery of the present invention is a battery cell in which a power source is housed, an electrode plate attached to the lid of the battery cell and caulked and fixed to the last electric component in the battery cell, and welded to the electrode plate. The electrode plate has an inclined surface formed so as to move away from the lid of the battery cell as the distance from the caulked fixing position increases, and the bus bar terminal has the caulked fixing position. A joint surface having an inclination that approaches the lid of the battery cell as it approaches the position and one end of the joint surface are continuously formed, and a load is applied to the joint surface in the direction toward the inclined surface. When the surface constituting the lid of the battery cell is a horizontal surface having a base portion for transmission, the first angle, which is an angle formed by the horizontal surface and the inclined surface, is the joint surface between the horizontal surface and the inclined surface. It is smaller than the second angle, which is the angle formed by the battery.

The assembled battery of the present invention applies a load that presses the joint surface of the welding target against the inclined surface via the base portion of the bus bar terminal different from the location of the welding target.

According to the assembled battery of the present invention, the assembled battery can be easily assembled.

It is a perspective view of a part of the assembled battery which concerns on Embodiment 1. FIG. It is a top view of a part of the assembled battery which concerns on Embodiment 1. FIG. It is a perspective view of the bus bar terminal of the assembled battery which concerns on Embodiment 1. FIG. It is a figure explaining the method of incorporating the bus bar terminal of the assembled battery which concerns on Embodiment 1. FIG. It is a figure explaining how the bus bar terminal of the assembled battery which concerns on Embodiment 1 absorbs the difference in the height of a battery cell. It is a figure explaining the structure of the spacer frame of the assembled battery which concerns on Embodiment 2. FIG. It is a figure explaining the state in which the battery cell is incorporated in the spacer frame of the assembled battery which concerns on Embodiment 2. FIG. It is a schematic diagram explaining the effect of the simplification of tolerance management by the spacer frame of the assembled battery which concerns on Embodiment 2. FIG. It is a schematic diagram explaining the effect of reducing the inclination of a battery cell by the spacer frame of the assembled battery which concerns on Embodiment 2. FIG.

Embodiment 1
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In order to clarify the explanation, the following description and drawings are omitted or simplified as appropriate. In each drawing, the same elements are designated by the same reference numerals, and duplicate explanations are omitted as necessary.

The assembled battery described below describes one of the battery stacks in which a plurality of battery cells are connected in series and functions as one battery, but the assembled battery may have a plurality of battery stacks connected in parallel. Further, in the following, the structural characteristics of the assembled battery, which is one of the characteristics of the assembled battery according to the first embodiment, will be described.

FIG. 1 shows a perspective view of a part of the assembled battery according to the first embodiment. In FIG. 1, seven of the battery cells constituting the battery stack are extracted. As shown in FIG. 1, the battery stack is a stack of battery cells 10 stacked so as to be laminated via a spacer frame 20. In FIG. 1, of the plurality of battery cells 10, only the battery cell 10 originally located on the right side can be seen, and the other battery cells 10 are hidden by the spacer frame 20. As shown in the battery cell 10 visible in FIG. 1, the battery cell 10 has an electrode plate 11 as an electrode.

Further, in the assembled battery 1 according to the first embodiment, the bus bar frame 30 is provided on the upper portion of the stacked batteries, and the electrodes of the two adjacent battery cells 10 are electrically connected by the bus bar terminals arranged in the bus bar frame 30. .. Hereinafter, the detailed configuration of the bus bar terminal and the electrode plate 11 to which the bus bar terminal is connected will be described.

In addition, in FIG. 1, the bus bar cover 40 is shown. The bus bar cover 40 is fitted in the upper part of the battery cell 10 and the spacer frame 20 laminated so as to connect the vicinity of the end portion of the bus bar frame 30 provided for each of the two electrodes of the battery cell 10. As will be described in detail later, the bus bar cover 40 also functions as a pressure component that applies a load to the bus bar terminal.

The bus bar terminal will be described with reference to FIG. FIG. 2 is a top view of a part of the assembled battery according to the first embodiment. Note that FIG. 2 shows a state in which the bus bar cover 40 is not attached in order to show the entire bus bar terminal 31. As shown in FIG. 2, in the assembled battery 1 according to the first embodiment, the bus bar terminal 31 is arranged in the frame of the bus bar frame 30. Further, the bus bar terminal 31 has a U-shape so as to connect the electrode plates 11 of two adjacent battery cells 10.

Subsequently, the configuration of a single bus bar terminal 31 will be described. FIG. 3 shows a perspective view of the bus bar terminal 31 of the assembled battery according to the first embodiment. As shown in FIG. 3, the bus bar terminal 31 has a U-shape. Then, a bonding surface 32a to be joined to the electrode plate 11 (hereinafter, also referred to as an electrode plate 11a) of one of the battery cells 10 of the battery cells 10 adjacent to each other is provided at one end, and the other end is provided with a bonding surface 32a. A bonding surface 32b to be joined to an electrode plate 11 (hereinafter, also referred to as an electrode plate 11b) of the other battery cell 10 of the battery cells 10 adjacent to each other is provided. Then, the base portion 33 is provided so as to connect one end of the joint surface 32a and the joint surface 32b. The base portion 33 has an L-shape when viewed from the side, and is connected to the joint surface 32a and the joint surface 32b at one end of the L-shape.

Further, as will be described in detail later, the plate thickness of the plate constituting the bus bar terminal 31 is formed to be thinner than the plate thickness of the plate constituting the electrode plate 11. In particular, the plate thickness of the joint surface 32a and the joint surface 32b of the bus bar terminal 31 is formed to be thinner than the plate thickness of the plate constituting the electrode plate 11. Further, when the surface constituting the lid of the battery cell 10 is a horizontal surface, the joint surface 32a and the joint surface 32b are housed in the bus bar frame 30, and the other end side of the open end is the battery cell with respect to the horizontal surface. It has an inclination that approaches the 10 side.

Subsequently, a method of incorporating the bus bar terminal 31 will be described. FIG. 4 shows a diagram illustrating a method of incorporating the bus bar terminal of the assembled battery according to the first embodiment. FIG. 4 is a cross-sectional view of the assembled battery 1 in which the joint portion between the joint surface 32 and the electrode plate 11 can be seen.

As shown in FIG. 4, in the assembled battery 1 according to the first embodiment, the electrode plate 11 is attached to the lid of the battery cell 10 and is caulked and fixed to the last train component in the battery cell 10. The electrode plate 11 has an inclined surface formed so as to move away from the lid of the battery cell 10 as the distance from the crimping fixing position increases. This inclined surface is formed so that when the lid of the battery cell 10 is a horizontal plane, the angle formed by the horizontal plane is the first angle α.

Further, in FIG. 4, the surface constituting the base portion 33 of the bus bar terminal 31 is composed of a parallel surface 33a and a vertical surface 33b. The parallel surface 33a and the vertical surface 33b are formed so as to have an L-shape along the frame body constituting the bus bar frame 30. Then, the joint surface 32a is provided so as to be continuously formed at one end of the vertical surface 33b. When the lid of the battery cell 10 is a horizontal plane, the joint surface 32a is formed so that the angle formed by the horizontal plane is the second angle β. Further, the joint surface 32a has an inclination toward the lid of the battery cell 10 as it approaches the position where the electrode plate 11 is fixed by caulking.

Then, in the assembled battery 1 according to the first embodiment, the bus bar cover 40 is pressed against the parallel surface 33a of the base portion 33, and a load is applied to the parallel surface 33a via the bus bar cover 40. As a result, the joint surface 32a is pressed against the electrode plate 11. At this time, since the base portion 33 has an L-shape, the joint surface 32a is likely to be displaced when the joint surface 32a is pressed against the electrode plate 11. Further, in the assembled battery 1 according to the first embodiment, the first angle α is made smaller than the second angle β. As a result, when the bus bar terminal 31 is pressed against the electrode plate 11, the joint surface 32a is displaced, and the difference in height of the battery cell 10, which will be described later, can be absorbed.

In the assembled battery 1 according to the first embodiment, the plate thickness of the bus bar terminal 31 is made thinner than the plate thickness of the electrode plate 11. In particular, it is preferable that the plate thickness of the joint surface of the bus bar terminal 31 is thinner than the plate thickness of the electrode plate 11. As a result, when the joint surface is pressed against the electrode plate 11, the joint surface 32 can be easily displaced.

Subsequently, in the assembled battery 1 according to the first embodiment, a state in which the bus bar terminal 31 is assembled to the adjacent battery cells 10 will be described. Therefore, FIG. 5 shows a diagram illustrating a state in which the difference in height of the battery cells is absorbed by the bus bar terminal of the assembled battery according to the first embodiment. FIG. 5 is a cross-sectional view of the assembled battery 1 along the VV line of FIG. 4, showing a portion including two battery cells 10.

In the example shown in FIG. 5, the battery cell 10a and the battery cell 10b adjacent to the battery cell 10a are shown. Further, FIG. 5 shows a state in which the battery cell 10b is assembled at a position higher by the height H with respect to the battery cell 10a.

In such a case, looking at the cross section along the line AA showing the bonding state between the electrode plate 11a and the bonding surface 32a of the battery cell 10a, the inclined surface of the electrode plate 11a and the bonding surface 32a are in contact with each other at the point a. At this time, since the inclined surface of the electrode plate 11a has an inclination so as to approach the joint surface 32a side, the distance between the inclined surface of the electrode plate 11a and the joint surface 32a is the distance between the joint surface 32a and the lid of the battery cell 10a. Not as far as the distance.

Further, looking at the cross section along the line BB showing the bonding state between the electrode plate 11b and the bonding surface 32b of the battery cell 10b, the inclined surface of the electrode plate 11b and the bonding surface 32b are in contact with each other. On the battery cell 10b side, when the bus bar terminal 31 is pressed against the electrode plate 11, the joint surface 32b is displaced by the height H, and the inclined surface of the electrode plate 11b and the joint surface 32b are in contact with each other. It becomes.

From the above description, in the assembled battery 1 according to the first embodiment, the joint surface of the bus bar terminal 31 is inclined so that the open end of the joint surface approaches the lid of the battery cell 10, and the base portion 33 of the bus bar terminal 31 is provided. By applying a load to the joint surface, a displacement that absorbs the height generated in the assembly of the adjacent battery cells 10 when the joint surface is pressed against the electrode plate 11 is generated on the joint surface. As a result, in the assembled battery 1 according to the first embodiment, the bus bar terminal 31 and the electrode plate 11 can be welded while applying a load to the welded portion of the bus bar terminal 31 without pressing the welded portion of the bus bar terminal 31. .. That is, in the assembled battery 1 according to the first embodiment, it is possible to facilitate the assembly of the assembled battery.

Further, in the assembled battery 1 according to the first embodiment, since the jig for applying a load to the bus bar terminal 31 is separated from the portion where the bus bar terminal 31 and the electrode plate 11 are welded, the jig is prevented from being contaminated by spatter. There is no need to take measures.

Further, in the assembled battery 1 according to the first embodiment, the first angle α is made smaller than the second angle β. As a result, in the assembled battery 1 according to the first embodiment, even if there is a difference in the assembled height of the two battery cells 10 to which the electrode plate 11 is electrically connected by the bus bar terminal 31, the difference in height is caused. It can be absorbed by the displacement of the joint surface. At this time, by making the plate thickness of the bus bar terminal 31 thinner than the plate thickness of the electrode plate 11, this displacement can be further facilitated.

Embodiment 2
In the second embodiment, the spacer frame 20 used in the assembled battery 1 will be described in detail. In the second embodiment, the surface on which the lid of the battery cell 10 is provided is the front surface, the surface facing the upper surface is the bottom surface, and the direction from the bottom surface to the surface is the height direction (for example, the Y direction), and one of the battery cells 10. The direction from one electrode to the other electrode is the width direction (for example, the X direction), and the direction orthogonal to the height direction and the width direction is the depth direction (for example, the Z direction).

FIG. 6 shows a diagram illustrating the structure of the spacer frame 20 of the assembled battery according to the second embodiment. In FIG. 6, a side view (for example, a right side view) of the spacer frame 20 seen from the X direction is shown in the middle part of the drawing, and a side view of the first surface seen from the left side of the right side view is shown in the upper part of the drawing. The side view of the second surface seen from the right side of the figure is shown in the lower part of the drawing.

As shown in FIG. 6, the spacer frame 20 has a frame surrounding the outer periphery of the spacer frame 20 on the first surface side. Then, the X reference plane is formed on the flat surface of the region surrounded by the frame. The X reference plane is in contact with the side surface of the battery cell 10 extending in the X direction. Further, a Y reference surface is formed on one of the first side surface and the second side surface facing the X direction among the surfaces constituting the frame. Further, the elastic portion 22 is formed on the surface facing the Y reference surface. The elastic portion 22 can also be formed on the Y reference plane. One of the side surfaces of the battery cell 10 facing in the X direction abuts on the Y reference surface.

The spacer frame 20 forms an elastic portion 23 on the upper surface of the surfaces constituting the frame facing in the Y direction and the lower surface of the lower surface. Further, a support surface (for example, a Z reference surface) is formed on the upper surface. As will be described in detail later, the electrode plate 11 of the battery cell 10 comes into contact with the Z reference surface. Further, on the side where the Z reference surface is formed, a spacer frame fixing claw 21 for fixing the bus bar frame 30 to the spacer frame 20 is formed.

Further, as shown in the lower part of FIG. 6, a comb tooth structure 24 is formed on the second surface. The comb tooth structure 24 constitutes a flow path for cooling air for cooling the battery cell 10.

Subsequently, a state in which the battery cell 10 is incorporated on the first surface side of FIG. 6 will be described. Therefore, FIG. 7 shows a diagram illustrating a state in which the battery cell is incorporated in the spacer frame of the assembled battery according to the second embodiment. As shown in FIG. 7, in the assembled battery 1 according to the second embodiment, the side surface of the battery cell 10 incorporated in the spacer frame 20 by the elastic portion 22 is pressed against the Y reference surface. Further, in the assembled battery 1 according to the second embodiment, the electrode plate 11 of the battery cell 10 incorporated in the spacer frame 20 by the elastic portion 23 is pressed against the Z reference plane.

At this time, the spacer frame 20 is configured to press the electrode plate 11 against the Z reference surface, thereby simplifying tolerance management. Further, in the spacer frame 20, the inclination of the battery cell 10 due to the case expansion of the battery cell 10 generated in the manufacturing process of the battery cell 10 is reduced by appropriately setting the width of the Z reference surface and the width of the elastic portion 23.

Therefore, the simplification of tolerance management and the effect of preventing the tilt of the battery cell 10 will be described with reference to FIGS. 7 and 8 by using a schematic diagram. In addition, in FIG. 7 and FIG. 8, a spacer frame 200 is shown as a comparative example in order to explain the effect of the spacer frame 20. Further, in FIGS. 7 and 8, the battery cell 10 described in the first embodiment is incorporated in the spacer frame 20, and the battery cell 100 having an electrode shape different from that of the battery cell 10 is incorporated in the spacer frame 200 as a comparative example. ..

First, FIG. 8 shows a schematic diagram illustrating the effect of simplifying tolerance management by the spacer frame 20 of the assembled battery according to the second embodiment. In FIG. 8, a comparative example in which the battery cell 100 is incorporated in the spacer frame 200 is shown in the upper row, and the battery cell 10 is incorporated in the spacer frame 20 according to the second embodiment in the lower row. The portion of the spacer frame 200 and the spacer frame 20 in which the Z reference surface abuts is different. Further, the spacer frame 200 has an elastic portion 22 and an elastic portion 220 and an elastic portion 230 corresponding to the elastic portion 23.

As shown in FIG. 8, in the comparative example, the Z reference surface of the spacer frame 200 abuts on the lid of the battery cell 100. In this case, there are two tolerances, a tolerance of length L10 from the bottom surface of the spacer frame 200 (for example, the welding reference surface) to the surface of the lid of the battery cell 100, and a tolerance of the thickness L20 of the electrode plate 110 to be welded. Must be managed.

On the other hand, in the spacer frame 20 according to the second embodiment, the Z reference surface abuts on the electrode plate 11 of the battery cell 10. Therefore, in the spacer frame 20 according to the second embodiment, if only the tolerance of the length L1 from the bottom surface of the spacer frame 200 (for example, the welding reference surface) to the surface of the electrode plate 11 of the battery cell 10 is managed, it is a welding target. The height of the electrode plate 11 can be controlled.

Subsequently, FIG. 9 shows a schematic diagram illustrating the effect of reducing the inclination of the battery cell by the spacer frame of the assembled battery according to the second embodiment. FIG. 9 shows a cross section of the spacer frame including the Z reference plane and the battery cell. Further, also in FIG. 9, a comparative example in which the battery cell 100 is incorporated in the spacer frame 200 is shown in the upper row, and the battery cell 10 is incorporated in the spacer frame 20 according to the second embodiment in the lower row.

As shown in FIG. 9, in the spacer frame 200 according to the comparative example, the difference between the width W120, which is the length of the Z reference surface in the Z direction, and the width W2 of the electrode plate 110 is the width of the Z reference surface of the spacer frame 20. It is larger than the difference between W12 and the width W2 of the electrode plate 11. Further, in the spacer frame 200 according to the comparative example, the difference between the width W110, which is the length of the elastic portion 230 in the Z direction, and the width W1 of the bottom surface of the battery cell 10 is the difference between the width W11 of the elastic portion 23 of the spacer frame 20 and the battery. It is larger than the difference from the width W1 of the bottom surface of the cell 10.

Here, in the spacer frame 200 according to the comparative example, the length (or width) of the portion in contact with the battery cell 10 is smaller than that in the spacer frame 20 according to the second embodiment. Therefore, if the battery cell 100 is bulged in the manufacturing process of the battery cell 100, the battery cell 100 may be tilted and fixed to the spacer frame 200, resulting in a fitting failure. However, in the spacer frame 20 according to the second embodiment, the length (or width) of the portion in contact with the battery cell 10 is larger than that of the spacer frame 200, so that the spacer frame 20 does not tilt even if swelling occurs. Can be fitted.

From the above description, according to the spacer frame 20 according to the second embodiment, even if the case expands in the battery cell 10 in the manufacturing process, the battery cell 10 can be fitted into the spacer frame 20 without tilting. If the battery cell 10 is tilted when the battery cell 10 is fitted into the spacer frame 20, there is a high possibility that a welding defect will occur when the bus bar terminal 31 is welded to the electrode plate 11. However, by using the spacer frame 20 according to the second embodiment, it is possible to prevent the battery cell 10 from tilting regardless of the expansion of the case of the battery cell 10, so that the reliability of welding between the bus bar terminal 31 and the electrode plate 11 can be improved. Can be improved.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit.

1 set battery 10 battery cell 11 electrode plate 20 spacer frame 21 spacer frame fixing claw 22 elastic part 23 elastic part 24 comb tooth structure 30 bus bar frame 31 bus bar terminal 32 joint surface 33 base part 40 bus bar cover

Claims (6)

The battery cell that houses the power unit and
An electrode plate attached to the lid of the battery cell and crimped to the last train component in the battery cell.
Has a bus bar terminal welded to the electrode plate,
The electrode plate has an inclined surface formed so as to move away from the lid of the battery cell as the distance from the caulked fixing position increases.
The bus bar terminal is
A joint surface having an inclination that approaches the lid of the battery cell as it approaches the caulking fixing position.
It has a base portion that is continuously formed with one end of the joint surface and transmits a load in a direction toward the inclined surface to the joint surface.
When the surface constituting the lid of the battery cell is a horizontal plane, the first angle formed by the horizontal plane and the inclined surface is larger than the second angle formed by the horizontal plane and the joint surface. Also a small set battery. The assembled battery according to claim 1, wherein the plate thickness of the plate constituting the inclined surface is thicker than the plate thickness of the plate constituting the joint surface. It has a bus bar frame that fixes the periphery of the bus bar terminal.
The assembled battery according to claim 1 or 2, wherein the base portion is formed in an L shape along a frame body constituting the bus bar frame. The assembled battery according to any one of claims 1 to 3, further comprising a pressure component that applies a load to the base portion toward the battery cell side. Further having a spacer frame provided between the plurality of battery cells,
The spacer frame is
The surface on which the lid of the battery cell is provided is the front surface, the surface facing the upper surface is the bottom surface, the direction from the bottom surface to the surface is the height direction, and the direction from one electrode of the battery cell to the other electrode is. When the width direction, the height direction, and the direction orthogonal to the width direction are defined as the depth direction,
The first side surface and the second side surface facing each other in the width direction,
The upper and lower surfaces facing each other in the height direction,
A first elastic portion provided on at least one of the first side surface and the second side surface, and
A second elastic portion provided on the lower surface and
A support surface provided on the upper surface and in contact with the electrode plate,
The assembled battery according to any one of claims 1 to 4. The length of the first elastic portion and the second elastic portion in the depth direction has a length of 70% or more of the length of the bottom surface of the battery cell in the depth direction.
The assembled battery according to claim 5, wherein the length of the support surface in the depth direction is 70% or more of the length of the electrode plate in the depth direction.

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