Bus bar holder mounting method and battery module

Abstract

To efficiently attach a bus bar holder to a cell laminate.SOLUTION: The bus bar holder attachment method includes an opening step and a closing step. An open guide having a width in the X direction increasing from the cell stack body side toward the insertion hole side in the Y direction is provided in a portion located closer to the cell stack body than the insertion hole in the Y direction in a portion including a portion between the insertion holes of the bus bar holder. An escape portion is provided in a portion of the tab lead located on the base end side with respect to the front end portion. In the opening step, the tab leads are inserted into the corresponding insertion holes, and the opening guide is inserted between the tab leads to be electrically connected to each other to open the leading ends of the tab leads in the X direction. In the closing step, by inserting the plurality of tab leads deeper into the insertion hole, the end portion of the opening guide in the X direction is inserted into the relief portion, and the leading end portion of the tab lead is returned to the closing side.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a technique for attaching a bus bar holder to a cell stack in which battery cells are stacked. [Background technology]

[0002] In recent years, electric vehicles such as EVs and HEVs have become increasingly popular in order to reduce carbon dioxide emissions and thereby mitigate adverse effects on the global environment. Some batteries installed in electric vehicles and the like include a cell stack consisting of multiple battery cells arranged in one direction. Each battery cell has a tab lead that protrudes in a direction perpendicular to the one direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-148244 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors have devised the following method of arranging bus bars between tab leads that are to be electrically connected to each other in such a cell stack: First, a bus bar holder is prepared that has a row of insertion holes through which a plurality of tab leads are inserted and that holds bus bars between the insertion holes.

[0005] Next, the bus bar holder is attached to the cell stack, and the bus bar is placed between the tab leads. The bus bar is then clamped together with the adjacent tab leads. In this state, the tab leads are welded to the bus bar.

[0006] However, the inventors have noticed that such a method has the following problem. Specifically, because battery cells have dimensional tolerances, when multiple battery cells are stacked side by side, the positions of each battery cell relative to the bus bar holder may deviate from the desired positions. As a result, when inserting the tab leads into the insertion holes, there is a risk that the tab leads may interfere with the periphery of the insertion holes or with the bus bars. This may result in inefficient attachment of the bus bar holder to the cell stack.

[0007] The present invention has been made in view of the above circumstances, and has an object to make it possible to efficiently attach bus bar holders to a cell stack. [Means for solving the problem]

[0008] The inventors discovered that the above object can be achieved by providing a bus bar holder with an opening guide that opens the tip ends of the tab leads in the X direction, and arrived at the present invention. The present invention relates to the following bus bar holder mounting method (1) and (2) and battery module (3).

[0009] (1) A bus bar holder mounting method for mounting a bus bar holder to a cell stack including a plurality of battery cells arranged in a predetermined X direction, the battery cells including tab leads protruding in a Y direction perpendicular to the X direction, the method comprising: when viewed in an attachment state when the bus bar holder is attached to the cell stack, the bus bar holder has insertion holes, through which the tab leads are inserted in the Y direction, aligned in the X direction, and holds bus bars between the insertion holes for electrically connecting the tab leads to each other; an opening guide whose width in the X direction increases as it moves from the cell stack side to the insertion hole side in the Y direction is provided in a portion of the bus bar holder including a space between the insertion holes and located closer to the cell stack side than the insertion hole in the Y direction when viewed in the installation state, a relief portion is provided in a portion of the tab lead that is located closer to the base end than the tip end, The bus bar holder mounting method includes: an opening step of inserting the plurality of tab leads into the corresponding insertion holes, thereby inserting the opening guide between the tab leads to be electrically connected to each other, and opening tip ends of the tab leads in the X direction; and a closing step of, after the opening step, inserting the plurality of tab leads further deeply into the insertion holes to insert the ends of the opening guides in the X direction into the relief portions, and returning the tip ends of the tab leads to the closing side in the X direction. How to install the busbar holder.

[0010] According to this configuration, in the opening step, by inserting the multiple tab leads into the corresponding insertion holes, opening guides are inserted between the tab leads to open the tip ends of the tab leads in the X direction. Therefore, simply by inserting the multiple tab leads into the corresponding insertion holes, the tip ends of the tab leads can be opened in the X direction. This makes it possible to avoid interference of the tab leads with the periphery of the insertion hole in the bus bar holder, etc.

[0011] Furthermore, in the subsequent closing process, the leading ends of the tab leads are returned to the closing side by inserting the tab leads further deeper into the insertion holes. Therefore, the leading ends of the tab leads can be returned to the closing side simply by inserting the tab leads further deeper into the insertion holes.

[0012] As a result, the bus bar holder can be efficiently attached to the cell stack.

[0013] (2) The tab lead is provided at both ends in a Z direction perpendicular to the X direction and the Y direction with the relief portion having a notch shape recessed in the Z direction, When viewed in the installation state, the opening guide is provided at both ends in the Z direction with protrusions that protrude in the X direction, The protrusion is inserted into the recess. The bus bar holder mounting method according to (1) above.

[0014] According to this configuration, the relief portion and the opening guide can be simply configured.

[0015] (3) a cell stack including a plurality of battery cells arranged in a predetermined X direction, the battery cells including tab leads protruding in a Y direction perpendicular to the X direction; a bus bar holder attached to the cell stack; A battery module comprising: the bus bar holder has insertion holes, through which the tab leads are inserted in the Y direction, aligned in the X direction, and holds bus bars between the insertion holes for electrically connecting the tab leads to each other, an opening guide whose width in the X direction increases as it moves from the cell stack side to the insertion hole side in the Y direction is provided in a portion of the bus bar holder including a space between the insertion holes and located closer to the cell stack side than the insertion hole in the Y direction, a relief portion is provided in a portion of the tab lead that is located closer to the base end than the tip end, The plurality of tab leads are inserted through the corresponding insertion holes, The end of the opening guide in the X direction is inserted into the relief portion. Battery module.

[0016] The battery module of this configuration can be manufactured by carrying out the method of (1) above, and therefore the same effects as in (1) above can be obtained. [Effects of the Invention]

[0017] As described above, the method of (1) and the battery module of (3) enable the bus bar holder to be efficiently attached to the cell stack. Furthermore, the configuration of (2) that cites (1) provides additional advantages. [Brief explanation of the drawings]

[0018] [Figure 1] 2 is an exploded cross-sectional view of the battery module of the first embodiment as viewed in the Z direction. FIG. [Figure 2] FIG. 2 is a cross-sectional view of the battery module as viewed in the Z direction. [Figure 3] 5 is an enlarged view of a part of FIG. 1, specifically a cross section taken along line fg3-fg3 in FIG. [Figure 4] FIG. 2 is an exploded perspective view showing the battery module. [Figure 5] FIG. 4 is a cross-sectional view taken along line fg5-fg5 in FIG. 3. [Figure 6] FIG. 6 is a cross-sectional view taken along line fg6-fg6 in FIGS. 3 and 5. [Figure 7] 10 is an enlarged view of a part of FIG. 1, specifically a cross section taken along line fg7-fg7 in FIG. [Figure 8] 10 is a cross-sectional view showing an opening step in the bus bar holder mounting method. FIG. [Figure 9] 12 is a cross-sectional view showing a closing step in the bus bar holder attaching method, specifically a cross-section taken along line fg9-fg9 in FIG. 11. FIG. [Figure 10] FIG. 8 is a cross-sectional view taken along line fg10-fg10 in FIG. 7. [Figure 11] FIG. 10 is a cross-sectional view taken along line fg11-fg11 in FIG. 9. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments and can be appropriately modified and implemented within the scope of the present invention.

[0020] [First embodiment] As shown in FIG. 1, the battery module 30 includes a cell stack 10 and two bus bar holders 20. Hereinafter, as shown in FIG. 4, three predetermined directions that are orthogonal to each other with respect to the cell stack 10 are referred to as the "X direction," "Y direction," and "Z direction." One side in the X direction is referred to as the "X- side," and the opposite side is referred to as the "X+" side. One side in the Y direction is referred to as the "Y- side," and the opposite side is referred to as the "Y+ side." One side in the Z direction is referred to as the "Z- side," and the opposite side is referred to as the "Z+ side."

[0021] 4, the cell stack 10 includes a housing 12 and a plurality of battery cells 15. The housing 12 includes two side plates 125 and 126, two end plates 121 and 123, and a center plate 122.

[0022] The two side plates 125, 126 are arranged side by side and spaced apart in the Z direction. Each side plate 125, 126 extends in the X and Y directions. The two end plates 121, 123 connect the X-direction ends of the two side plates 125, 126. The center plate 122 connects the X-direction middle portions of the two side plates 125, 126. Each end plate 121, 123 and the center plate 122 extend in the Y and Z directions.

[0023] Battery cells 15 extending in the Y and Z directions are arranged in the X direction and stored inside the housing 12. Specifically, half of the battery cells 15 are stored between the X-side end plate 121 and the center plate 122. On the other hand, the other half of the battery cells 15 are stored between the center plate 122 and the X+ side end plate 123.

[0024] 1, each battery cell 15 includes a cell body 152, Y+-side tab leads P and N that protrude from the Y+-side end of the cell body 152 to the Y+ side, and Y-side tab leads N and P that protrude from the Y-side end of the cell body 152 to the Y- side. Each tab lead P and N is plate-shaped and extends in the Y and Z directions. In each battery cell 15, one of the two tab leads P and N on both sides in the Y direction is a positive-side tab lead P, and the other is a negative-side tab lead N.

[0025] Hereinafter, the arrangement of the battery cells 15 in which the positive electrode side tab lead P is arranged on the Y+ side and the negative electrode side tab lead N is arranged on the Y- side will be referred to as the "positive-negative arrangement." Also, the arrangement of the battery cells 15 in which the negative electrode side tab lead N is arranged on the Y+ side and the positive electrode side tab lead P is arranged on the Y- side will be referred to as the "negative-positive arrangement."

[0026] In the cell stack 10, the battery cells 15 in a positive-negative arrangement and the battery cells 15 in a negative-positive arrangement are alternately arranged in the X direction. Specifically, the battery cell 15 closest to the X- side is in a positive-negative arrangement, and the battery cell 15 closest to the X+ side is in a negative-positive arrangement.

[0027] As a result of the above, at the Y+ side end of the cell stack 10 and the Y- side end of the cell stack 10, the positive electrode side tab leads P and the negative electrode side tab leads N are arranged alternately in the X direction.

[0028] 5, a notched relief portion d recessed toward the Z- side is provided in a portion of the Z+ side end of each tab lead P, N that is located closer to the base end than the tip end in the Y direction. Also, a notched relief portion d recessed toward the Z+ side is provided in a portion of the Z- side end of each tab lead P, N that is located closer to the base end than the tip end in the Y direction. The function of these relief portions d will be described later.

[0029] Next, the two busbar holders 20 shown in FIG. 1 will be described. Each busbar holder 20 is made of an insulating material such as resin. One busbar holder 20 is attached to the Y+ side end of the cell stack 10. The other busbar holder 20 is attached to the Y- side end of the cell stack 10. Hereinafter, the busbar holder 20 attached to the Y+ side end of the cell stack 10 will be referred to as the "Y+ side busbar holder 20." Additionally, the busbar holder 20 attached to the Y- side end of the cell stack 10 will be referred to as the "Y- side busbar holder 20."

[0030] In the following description, the state in which the bus bar holder 20 is attached to the cell stack 10 is referred to as the "attachment state iS." When viewed in the attachment state iS, the Y-side bus bar holder 20 is configured as follows.

[0031] 4, the bus bar holder 20 on the Y-side extends in the X and Z directions. The bus bar holder 20 has insertion holes 22 extending in the Z direction formed therein and spaced apart in the X direction.

[0032] A negative electrode bus bar 25n is held in a portion of the Y-side surface of the Y-side bus bar holder 20 that is located closer to the X-side than the X-side insertion hole 22. The negative electrode bus bar 25n is a conductor that connects the negative electrode tab lead N of the negative electrode side battery cell 15 to the negative electrode terminal of the entire battery module 30. The negative electrode bus bar 25n extends in the Z direction and also extends from the Z+ side end toward the X+ side.

[0033] On the Y-side surface of the Y-side bus bar holder 20, connecting bus bars 25 for electrically connecting the tab leads P, N are held between each even-numbered insertion hole 22 from the X-side and its adjacent insertion hole 22 on the X+ side. Each of these connecting bus bars 25 is a conductor for electrically connecting the positive electrode side tab lead P with the negative electrode side tab lead N adjacent to it on the X+ side, and extends in the Z direction.

[0034] A positive electrode bus bar 25p is held in a portion of the Y-side surface of the Y-side bus bar holder 20 that is located closer to the X+ side than the X+-side insertion hole 22. The positive electrode bus bar 25p is a conductor that connects the positive electrode tab lead P of the most positive electrode battery cell 15 to the positive electrode terminal of the entire battery module 30. The positive electrode bus bar 25p extends in the Z direction and also extends from the Z+ side end toward the X- side.

[0035] These bus bars 25n, 25, 25p are held by the bus bar holder 20 by, for example, holes or recesses provided on the bus bars 25n, 25, 25p engaging with protrusions provided on the bus bar holder 20.

[0036] As shown in FIG. 3 , opening guides 23 whose width in the X direction increases toward the Y− side are provided on the Y+-side surface of the Y−-side bus bar holder 20 in a portion located on the Y+ side of each bus bar 25n, 25, 25p. Specifically, in this embodiment, each opening guide 23 has a triangular shape when viewed in the Z direction, but other shapes are also possible. Specifically, for example, the opening guide 23 may have a trapezoidal shape obtained by removing the Y+-side tip from this triangle. As shown in FIG. 6 , groove-shaped notches f that are recessed in the X direction and extend in the Z direction are provided in the middle of both X-direction end portions of the opening guide 23 in the Z direction. As a result, protrusions e that protrude in the X direction are formed at both Z-direction end portions of both X-direction end portions of the opening guide 23.

[0037] The above description is of the Y-side bus bar holder 20 when viewed in the mounting state iS.

[0038] Next, the Y+-side busbar holder 20 shown in FIG. 1 will be described. The description of this Y+-side busbar holder 20 is substantially the same as the description of the Y-side busbar holder 20 above, but differs in the following respects. That is, "FIGS. 3" and "4" are replaced with "FIG. 1." Also, "Y-side" and "Y+ side" are replaced with the other, and "even-numbered" is replaced with "odd-numbered." Also, description of the negative electrode busbar 25n and the positive electrode busbar 25p will be omitted. That is, the Y+-side busbar holder 20 does not hold the negative electrode busbar 25n or the positive electrode busbar 25p, but only holds multiple connecting busbars 25.

[0039] Next, we will explain the Y+ side bus bar holder attachment method for attaching the Y+ side bus bar holder 20 to the Y+ side end of the cell stack 10. Note that this Y+ side bus bar holder attachment method may be performed manually by a worker or the like, or may be performed automatically by a machine or the like.

[0040] In this Y+-side bus bar holder attachment method, a predetermined opening process is first performed. In this opening process, Y+-side bus bar holder 20 shown in FIG. 7 is moved from the Y+ side of each Y+-side tab lead P, N toward the Y- side as shown in FIG. 8. As a result of this movement, the leading ends of tab leads P, N are guided by opening guide 23 by contacting its guide surface (inclined surface), and each tab lead P, N is inserted into its corresponding insertion hole 22. As a result, opening guide 23 is inserted between tab leads P, N that are to be electrically connected to each other. The leading ends of tab leads P, N are opened in the X direction by opening guide 23.

[0041] From this state, a predetermined closing process is performed. In this closing process, the bus bar holder 20 on the Y+ side shown in FIG. 8 is moved further toward the Y- side as shown in FIG. 9. This causes each tab lead P, N to be inserted further deeply into the insertion hole 22. As a result, the protrusions e at both ends in the Z direction of the X-direction ends of the opening guide 23 are inserted into the corresponding relief portions d, as shown in FIG.

[0042] 9 are then welded to the adjacent bus bar 25. However, if the tab leads P and N are electrically connected to the adjacent bus bar 25 in a sufficiently stable manner without welding, this welding may be omitted. Alternatively, instead of or in addition to welding, the tip of each tab lead P and N may be bent to ensure electrical connection between the tab lead P and N and the adjacent bus bar 25.

[0043] Next, we will explain the Y-side busbar holder attachment method for attaching the Y-side busbar holder 20 to the Y-side end of the cell stack 10 shown in Fig. 1. The explanation for this Y-side busbar holder attachment method is substantially the same as the explanation for the Y+side busbar holder attachment method shown above, but differs in the following respects. That is, descriptions of referenced drawings will be omitted, and the "Y-side" and "Y+ side" will be read as the other side.

[0044] Next, a battery module 30 manufactured using the above-described method for attaching the Y+ and Y- side bus bar holders will be described. In the completed state of the battery module 30 shown in Fig. 2, each tab lead P, N is inserted all the way into the corresponding insertion hole 22. Therefore, as shown in Fig. 9, each protrusion e of the opening guide 23 is inserted into the relief portion d.

[0045] The configuration and effects of this embodiment are summarized below.

[0046] 8, in the opening step, by inserting each tab lead P, N into the corresponding insertion hole 22, opening guide 23 is inserted between tab leads P, N. The opening guide 23 opens the tip ends of tab leads P, N in the X direction. Therefore, simply by inserting each tab lead P, N into the corresponding insertion hole 22, the tip ends of tab leads P, N can be opened in the X direction. This makes it possible to avoid interference of each tab lead P, N with the periphery of insertion hole 22 in bus bar holder 20, etc.

[0047] 9, by inserting each tab lead P, N further deeper into the insertion hole 22, the protrusion e is inserted into the recess d, and the tip ends of the tab leads P, N are returned to the closing side. Therefore, simply by inserting each tab lead P, N further deeper into the insertion hole 22, the tip ends of the tab leads P, N can be returned to the closing side.

[0048] As a result, the bus bar holder 20 can be attached to the cell stack 10 efficiently.

[0049] As shown in Fig. 10, both ends of the tab leads P and N in the Z direction are provided with notched relief portions d recessed in the Z direction. When viewed in the mounting state iS, both ends of the opening guide 23 in the X direction are provided with protrusions e protruding in the X direction. As shown in Fig. 11, these protrusions e are inserted into the corresponding relief portions d. This allows the relief portions d and the opening guide 23 to be configured simply.

[0050] In the completed battery module 30 shown in Fig. 2, each tab lead P, N is inserted through the corresponding insertion hole 22. As shown in Fig. 9, the protrusion e of the opening guide 23 is inserted into the relief portion d. Therefore, by carrying out the bus bar holder mounting method of this embodiment, the battery module 30 shown in Fig. 2 can be manufactured as is.

[0051] [Other embodiments] The embodiment described above can be modified, for example, as follows: The protrusions e shown in Fig. 5 may be provided at the middle portion in the Z direction instead of at both ends in the X direction of the opening guide 23. The relief portions d may be provided in the form of through holes at the middle portion in the Z direction of the tab leads P and N. [Explanation of symbols]

[0052] 10 Cell stack 15 battery cells 20 Busbar holder 22 Insertion hole 23 Opening guide 25 Busbar 30 Battery Module d Relief e protrusion iS installation state N Negative electrode tab lead P Positive electrode tab lead

Claims

1. A bus bar holder mounting method for mounting a bus bar holder to a cell stack including a plurality of battery cells arranged in a predetermined X direction, the battery cells including tab leads protruding in a Y direction perpendicular to the X direction, the method comprising: when viewed in an attachment state when the bus bar holder is attached to the cell stack, the bus bar holder has insertion holes, through which the tab leads are inserted in the Y direction, aligned in the X direction, and holds bus bars between the insertion holes for electrically connecting the tab leads to each other; an opening guide whose width in the X direction increases as it moves from the cell stack side to the insertion hole side in the Y direction is provided in a portion of the bus bar holder including a space between the insertion holes when viewed in the mounting state, the opening guide being located closer to the cell stack side than the insertion hole in the Y direction; a relief portion is provided in a portion of the tab lead that is located closer to the base end than the tip end, The bus bar holder mounting method includes: an opening step of inserting the plurality of tab leads into the corresponding insertion holes, thereby inserting the opening guide between the tab leads to be electrically connected to each other, and opening tip ends of the tab leads in the X direction; and a closing step of, after the opening step, inserting the plurality of tab leads further deeply into the insertion holes to insert the ends of the opening guides in the X direction into the relief portions, thereby returning the tip ends of the tab leads to the closing side in the X direction. How to install the busbar holder.

2. the tab lead is provided at both ends in a Z direction perpendicular to the X direction and the Y direction with the relief portion having a notch shape recessed in the Z direction, When viewed in the installation state, the opening guide is provided at both ends in the Z direction with protrusions that protrude in the X direction, The protrusion is inserted into the recess. The bus bar holder mounting method according to claim 1 .

3. a cell stack including a plurality of battery cells arranged in a predetermined X direction, the battery cells including tab leads protruding in a Y direction perpendicular to the X direction; a bus bar holder attached to the cell stack; A battery module comprising: the bus bar holder has insertion holes, through which the tab leads are inserted in the Y direction, aligned in the X direction, and holds bus bars between the insertion holes for electrically connecting the tab leads to each other, an opening guide whose width in the X direction increases as it moves from the cell stack side to the insertion hole side in the Y direction is provided in a portion of the bus bar holder that includes a space between the insertion holes and is located closer to the cell stack side than the insertion hole in the Y direction, a relief portion is provided in a portion of the tab lead that is located closer to the base end than the tip end, The plurality of tab leads are inserted through the corresponding insertion holes, The end of the opening guide in the X direction is inserted into the relief portion. Battery module.

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