Battery module

Abstract

A battery module (1A) is provided with: a plurality of battery cells (20a-20d) stacked on each other; heat transfer members (40a, 40b) that have electrical insulating properties and cover the peripheries of the positive and negative electrode tabs (21a-21d, 22a-22d) of the plurality of battery cells (20a-20d); and cooling jackets (50a, 50b) that have an internal space (51) through which a refrigerant (R) flows and that are in contact with the heat transfer members (40a, 40b).

Description

Technical Field

[0001] The present invention relates to a battery module. Background Art

[0002] There is a known power storage device having: a single cell stack formed by laminating power storage cells; a bus bar joined to a lead plate of the power storage cell; and a tubular flow path formed along the bus bar (for example, Patent Document 1). In this power storage device, a heat medium is circulated through the flow path to cool or heat the bus bar.

[0003] Prior art documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-24886 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] However, in the power storage cell of the above-described prior art, the cooling flow path is in line contact with the bus bar of the power storage cell, and the heat conduction efficiency between the flow path and the bus bar is poor. Therefore, there is a problem that the cooling efficiency of the battery cell deteriorates.

[0008] The problem to be solved by the present invention is to provide a battery module capable of improving the cooling efficiency of a battery cell.

[0009] Means for Solving the Problems

[0010] The present invention solves the above problems by providing: a heat transfer member having electrical insulation and covering the periphery of the lead plates of a plurality of battery cells; and a cooling jacket having an internal space through which a refrigerant flows and being in contact with the heat transfer member.

[0011] Effects of the Invention

[0012] According to the present invention, by covering the periphery of the lead plates of the battery cells with the heat transfer member and bringing the cooling jacket into contact with the heat transfer member, the heat conduction efficiency between the lead plates and the heat transfer member can be improved, and the cooling efficiency of the battery cells can be improved. Brief Description of the Drawings

[0013] Figure 1 is a perspective view showing an example of the structure of a battery module according to an embodiment of the present invention.

[0014] Figure 2 is a sectional view taken along line II-II of Figure 1

[0015] Figure 3 ​It is a cross-sectional view showing an example of the structure of the battery module of the first modification.

[0016] Figure 4 It is a top view showing an example of the structure of the battery module of the second modification.

[0017] Figure 5 It is a top view showing an example of the structure of the battery module of the third modification. Detailed implementation mode

[0018] Based on the drawings, the battery module 1A of this implementation mode will be described. Figure 1 It is a perspective view showing an example of the structure of the battery module 1A of this implementation mode. Figure 2 It is along Figure 1 Cross-sectional view taken along line II-II.

[0019] As Figure 1 and Figure 2 shown, the battery module 1A of this implementation mode includes a battery case 10, a plurality of battery cells 20a to 20d (refer to Figure 2 ), a pair of bus bars 30a, 30b, a pair of heat transfer members 40a, 40b, a pair of cooling jackets 50a, 50b, and a pair of heat insulating members 60a, 60b.

[0020] The battery case 10 houses the battery cells 20a to 20d inside. As Figure 1 shown, the battery case 10 has a case main body 11 and a lid member 12. The case main body 11 has an upper end and a box shape with openings at both ends. The battery cells 20a to 20d are housed inside the case main body 11. The lid member 12 closes the opening at the upper end of the case main body 11.

[0021] As Figure 2 shown, the battery cells 20a to 20d have a flat shape and are stacked on top of each other along the Z direction in the figure. The battery cells 20a to 20d are secondary batteries such as lithium-ion secondary batteries. Although this secondary battery is not particularly shown, it includes a positive electrode, an electrolyte, and a negative electrode. In addition, the electrolyte can be either a liquid electrolyte or a solid electrolyte. Also, the shape of the battery cells 20a to 20d is not limited to the above shape.

[0022] The battery cells 20a to 20d also include metallic positive electrode lead plates 21a to 21d connected to the positive electrode and metallic negative electrode lead plates 22a to 22d connected to the negative electrode. The positive electrode lead plates 21a to 21d extend from the first end portions 23a of the battery cells 20a to 20d. On the other hand, the negative electrode lead plates 22a to 22d extend from second end portions 23b different from the first end portions 23a. The positive electrode lead plates 21a to 21d and the negative electrode lead plates 22a to 22d are exposed with respect to the battery case 10 at the openings at both ends of the case main body 11 of the battery case 10.

[0023] The positive electrode lead plate 21a of the battery cell 20a is connected to a metallic bus bar 30a by welding or the like. In addition, one main surface (the lower surface in this example) of the positive electrode lead plate 21a is in contact with the heat transfer member 40a. On the other hand, the other main surface (the upper surface in this example) of the positive electrode lead plate 21a is exposed from the heat transfer member 40a.

[0024] The negative electrode lead plate 22a of the battery cell 20a and the positive electrode lead plate 21b of the battery cell 20b are embedded in the heat transfer member 40b and are connected to each other by welding or the like. In addition, the negative electrode lead plate 22b of the battery cell 20b and the positive electrode lead plate 21c of the battery cell 20c are embedded in the heat transfer member 40a and are connected to each other by welding or the like. In addition, the negative electrode lead plate 22c of the battery cell 20c and the positive electrode lead plate 21d of the battery cell 20d are embedded in the heat transfer member 40a and are connected to each other by welding or the like.

[0025] On the other hand, the negative electrode lead plate 22d of the battery cell 20d is connected to a metallic bus bar 30b by welding or the like. In addition, the other main surface (the upper surface in this example) of the negative electrode lead plate 22d is in contact with the heat transfer member 40a. On the other hand, one main surface (the lower surface in this example) of the positive electrode lead plate 22d is exposed from the heat transfer member 40a.

[0026] As described above, in the present embodiment, the mutually stacked battery cells 20a to 20d are connected in series and are connected to the bus bars 30a and 30b at their upper ends and lower ends, respectively. In addition, the battery cells 20a to 20d may be connected in series or in parallel. In addition, in the present embodiment, the positive electrode lead plates 21b to 21d and the negative electrode lead plates 22a to 22c are directly connected to each other, but are not limited thereto, and may be electrically connected via a bus bar.

[0027] The heat transfer members 40a and 40b cover both side surfaces of the battery cells 20a to 20d and cover the peripheries of the positive electrode lead plates 21a to 21d and the negative electrode lead plates 22a to 22d. The widths of the heat transfer members 40a and 40b in the present embodiment are smaller than the widths of the first end portions 23a and the second end portions 23b of the battery cells 20a to 20d.

[0028] The heat transfer members 40a and 40b have electrical insulation properties and are made of members with relatively high thermal conductivity. The thermal conductivity of the heat transfer members 40a and 40b can be, for example, 1 to 10 W / mK. As the heat transfer members 40a and 40b, for example, they can be fabricated by molding a resin containing fillers and the like on the sides of the battery cells 20a to 20d. As fillers, for example, fibrous or particulate silicon and the like can be exemplified.

[0029] In addition, in the present embodiment, the heat transfer member 40a is in contact with the bus bars 30a and 30b. In the present embodiment, a part of the main surface of the bus bars 30a and 30b is in contact with the heat transfer member 40a, but it is not limited thereto, and a part of the bus bars 30a and 30b can also be buried in the heat transfer member 40a.

[0030] A pair of cooling jackets 50a and 50b are provided outside the heat transfer members 40a and 40b. As Figure 1 shown, the cooling jacket 50a has a rectangular parallelepiped shape, and this rectangular parallelepiped shape has a width substantially the same as the width of the heat transfer member 40a, and the cooling jacket 50a is in surface contact with the heat transfer member 40a. Similarly, the cooling jacket 50b has a width substantially the same as the width of the heat transfer member 40b and is in surface contact with the heat transfer member 40b. The cooling jackets 50a and 50b in the present embodiment are an example of the "first cooling jacket" in the present invention.

[0031] The cooling jackets 50a and 50b are cooling sources for cooling the battery cells 20a to 20d across the heat transfer members 40a and 40b. The cooling jackets 50a and 50b are made of, for example, a laminated film having an insulating layer and a metal layer. In this case, an insulating layer such as a resin layer can be provided on the surface of the metal layer.

[0032] The cooling jackets 50a and 50b include an internal space 51 through which the refrigerant R flows. In addition, as long as the refrigerant is a fluid that can cool the battery cells 20a to 20d, any fluid can be used, and it can be either a liquid or a gas.

[0033] The cooling jackets 50a and 50b in the present embodiment each have parallel portions 52, 52 extending along a first direction substantially parallel to the stacking direction (Z direction in the figure) of the battery cells 20a to 20d. Therefore, in the parallel portions 52, the internal space 51 also extends along the first direction, and thus the refrigerant R also flows along the first direction. In addition, although not particularly shown, the cooling jackets 50a and 50b can also be connected to devices such as a pump and a radiator through flow paths.

[0034] On the outer sides of the parallel portions 52 of the cooling jackets 50a and 50b, heat insulating members 60a and 60b are provided. The heat insulating members 60a and 60b in the present embodiment cover the outer surfaces of the heat transfer members 40a and 40b and the cooling jackets 50a and 50b. The heat insulating members 60a and 60b have shapes similar to the outer surfaces of the heat transfer members 40a and 40b and the cooling jackets 50a and 50b. In the present embodiment, when viewed in plan, they have a Japanese character コ (U) shape and are bent so as to protrude toward the outside of the battery module 1A.

[0035] The heat insulating members 60a and 60b are formed of a heat-insulating material. There is no particular limitation on the heat-insulating material, but for example, a resin material having heat insulation properties can be exemplified. More specifically, as the resin material having heat insulation properties, a foam resin such as polyurethane foam can be exemplified. By using such heat insulating members 60a and 60b, the heat transferred from the positive and negative electrode lead plates 21a to 21d and 22a to 22d can be concentrated on the cooling jackets 50a and 50b, and thus the heat dissipation effect can be improved.

[0036] As long as it is the battery module 1A of the present embodiment as described above, the heat transfer members 40a and 40b cover the peripheries of the positive and negative electrode lead plates 21a to 21d and 22a to 22d of the battery cells 20a to 20d, and the cooling jackets 50a and 50b are brought into contact with the heat transfer members 40a and 40b, so that the heat conduction efficiency between the positive and negative electrode lead plates 21a to 21d and 22a to 22d and the heat transfer members 40a and 40b can be improved, and the cooling efficiency (heat dissipation effect) of the battery cells 20a to 20d can be enhanced.

[0037] In addition, as long as it is such a battery module 1A, the cooling efficiency can be improved by using the heat transfer members 40a and 40b. Therefore, without increasing the size of the cooling mechanism such as the cooling jackets 50a and 50b, an energy-saving effect can be obtained. As a result, the volumetric energy density, weight energy density, required electric energy, and required cost can be satisfied.

[0038] In particular, in the present embodiment, the heat transfer members 40a and 40b are in three-dimensional contact with the positive and negative electrode lead plates 21a to 21d and 22a to 22d, so that the heat conduction coefficient between the heat transfer members 40a and 40b and the positive and negative electrode lead plates 21a to 21d and 22a to 22d can be increased, and the cooling efficiency of the battery cells 20a to 20d can be enhanced.

[0039] In addition, in the present embodiment, instead of directly cooling the main bodies (electrode laminated portions) of the battery cells 20a to 20d, the positive and negative electrode lead plates 21a to 21d, 22a to 22d are cooled. According to the insight of the present inventor, the positive and negative electrode lead plates 21a to 21d, 22a to 22d are more likely to become high temperature than the main bodies of the battery cells 20a to 20d. Therefore, as long as it is the battery module 1A of the present embodiment, the risk caused by the temperature rise of the positive and negative electrode lead plates 21a to 21d, 22a to 22d can be reduced.

[0040] In addition, in the above embodiment, the case where the cooling jackets 50a, 50b have parallel portions 52 extending in the first direction (Z direction in the figure) has been described, but it is not limited thereto. For example, as in the following first modification example, the cooling jackets 50c, 50d may have vertical portions 53a to 53e extending in a second direction substantially perpendicular to the first direction.

[0041] Figure 3 It is a cross-sectional view showing an example of the structure of the battery module 1B of the first modification example. As Figure 3 shown, compared with the battery module 1A of the above embodiment, the battery module 1B of the present modification example is different from the battery module 1A of the above embodiment in that (1) the cooling jackets 50a, 50b have vertical portions 53a to 53e extending in the second direction (Y direction in the figure). However, except for this, the structure is the same as that of the above embodiment. Hereinafter, for the battery module 1B in the first modification example, only the differences from the above embodiment will be described, and for the structures that are the same as those of the above embodiment, the same reference numerals will be given and the description will be omitted.

[0042] In the first modification example, the cooling jacket 50c has tubular vertical portions 53a, 53b. The vertical portions 53a, 53b extend in the second direction (Y direction in the figure). In addition, the vertical portion 53a is buried in the heat transfer member 40a so as to be located between the positive electrode lead plate 21a and the negative electrode lead plate 22b. On the other hand, the vertical portion 53b is buried in the heat transfer member 40a so as to be located between the positive electrode lead plate 21c and the negative electrode lead plate 22d. Although not particularly shown, the cooling jacket 50c has a meandering shape in which the above vertical portions 53a, 53b are located between the positive electrode lead plate 21a and the negative electrode lead plate 22b and between the positive electrode lead plate 21c and the negative electrode lead plate 22d, and the vertical portions 53a, 53b are connected to each other by the bent portions of the meandering shape. In addition, the vertical portions 53a, 53b may be separate.

[0043] The cooling jacket 50d has tubular vertical portions 53c to 53e. The vertical portions 53c to 53e also extend along the second direction (the Y direction in the figure). The vertical portion 53c is located above the negative electrode lead plate 22a, and a part of the vertical portion 53c is exposed from the heat transfer member 40b. On the other hand, the vertical portion 53d is embedded in the heat transfer member 40b so as to be located between the positive electrode lead plate 21b and the negative electrode lead plate 22c. In addition, the vertical portion 53e is located below the positive electrode lead plate 21d, and a part of the vertical portion 53e is exposed from the heat transfer member 40b. Although not particularly shown, the cooling jacket 50d also has a meandering shape, and the vertical portions 53c to 53e are connected to each other by the bent portions of the meandering shape. In addition, the vertical portions 53c to 53e may also be separate.

[0044] Even for the battery module 1B in such a first modification, it is possible to improve the cooling efficiency in the same manner as the battery module 1A of the above-described embodiment.

[0045] In particular, in this modification, since the cooling jackets 50c and 50d are embedded in the heat transfer members 40a and 40b, the distances between the cooling jackets 50c and 50d and the positive and negative electrode lead plates 21a to 21d and 22a to 22d can be reduced. Therefore, it is possible to improve the cooling efficiency.

[0046] In addition, in the above-described embodiment, the case where the cooling jackets 50a and 50b are provided only on the top end 24 side of the positive and negative electrode lead plates 21a to 21d and 22a to 22d has been described, but it is not limited thereto. For example, cooling jackets 50e to 50h may also be provided as in the following second modification.

[0047] Figure 4 It is a top view showing an example of the structure of the battery module 1C of the second modification. Hereinafter, for the battery module 1C in the second modification, only the differences from the battery module 1A of the above-described embodiment will be described, and the same reference numerals are given to the structures that are the same as those of the battery module 1A and the description thereof is omitted.

[0048] In the second modification, the cooling jackets 50e and 50f are provided on both sides of the positive and negative electrode lead plates 21a, 22b, 21c, and 22d along the first end portions 23a of the battery cells 20a to 20d. The cooling jackets 50e and 50f have parallel portions 52 in the same manner as in the above-described embodiment. However, the parallel portions 52 of the cooling jackets 50e and 50f have a width corresponding to the side surfaces of the positive and negative electrode lead plates 21a, 22b, 21c, and 22d, and are narrower than the width of the parallel portion 52 of the cooling jacket 50a.

[0049] Similarly, the cooling jackets 50g and 50h are disposed on both sides of the positive and negative electrode lead plates 22a, 21b, 22c, and 21d along the second end portions 23b of the battery cells 20a to 20d. The cooling jackets 50g and 50h also have parallel portions 52, similarly to the cooling jackets 50e and 50f.

[0050] In addition, in the present embodiment, the cooling jackets 50a, 50b, 50g to 50h are embedded in the heat transfer members 40a and 40b, but are not limited thereto, and may also be in contact with the heat transfer members 40a and 40b from the outside.

[0051] Even for the battery module 1C in this second modification, it is possible to improve the cooling efficiency in the same manner as the battery module 1A of the above-described embodiment. In particular, in this modification, the cooling efficiency can be further improved by increasing the number of cooling jackets.

[0052] In addition, in the above-described embodiment, the case where the positive and negative electrode lead plates extend from the first end portion and the second end portion has been described, but is not limited thereto. The positive and negative electrode lead plates may extend from the same end portion (the second end portion 23b in the following modification).

[0053] In this case, the cooling jacket 50a is also embedded in the heat transfer member 40b and is in contact with the heat transfer member 40b. In this third modification, cooling jackets 50i and 50j are provided on both sides of the positive and negative electrode lead plates 21a, 22b, 21c, and 22d, and cooling jackets 50j and 50k are provided on both sides of the positive and negative electrode lead plates 22a, 21b, 22c, and 21d. In addition, the cooling jackets 50i to 50k in this modification have the same structure as the structure of the cooling jackets 50e to 50h in the second modification.

[0054] Even for the battery module 1D in this third modification, it is possible to improve the cooling efficiency in the same manner as the battery module 1A of the above-described embodiment. In particular, in this modification, the cooling efficiency can also be further improved by increasing the number of cooling jackets in the same manner as in the second modification.

[0055] Description of Reference Numerals

[0056] 1A, battery module; 10, battery case; 11, case main body; 12, cover member; 20a to 20d, battery cells; 21a to 21d, positive electrode lead plates; 22a to 22d, negative electrode lead plates; 23a, 23b, first end portion, second end portion; 24, tip; 30a, 30b, bus bars; 40a, 40b, heat transfer members; 50a to 50d, cooling jackets; 51, internal space; 52, parallel portion; 53a to 53d, vertical portions; 60a, 60b, heat insulating members; R, refrigerant.

Claims

1. A battery module, comprising: a plurality of battery cells stacked on one another; a heat transfer member having electrical insulation and covering the periphery of the lead plates of the plurality of battery cells; and a cooling jacket having an internal space through which a refrigerant flows and being in contact with the heat transfer member.

2. The battery module according to claim 1, wherein the cooling jacket has a parallel portion extending along a first direction substantially parallel to the stacking direction of the plurality of battery cells, and the refrigerant flows along the first direction in the parallel portion.

3. The battery module according to claim 1, wherein the cooling jacket has a perpendicular portion extending along a second direction substantially perpendicular to the stacking direction of the plurality of battery cells, and the refrigerant flows along the second direction in the perpendicular portion.

4. The battery module according to claim 2 or 3, wherein the cooling jacket is provided outside the heat transfer member.

5. The battery module according to claim 2 or 3, wherein the cooling jacket is embedded in the heat transfer member.

6. The battery module according to claim 5, wherein the cooling jacket is located between the plurality of lead plates.

7. The battery module according to claim 1, wherein the lead plates include a positive electrode lead plate and a negative electrode lead plate, and the positive electrode lead plate and the negative electrode lead plate extend respectively from the same end portion or different end portions of the battery cell.

8. The battery module according to claim 7, wherein the cooling jacket includes a first cooling jacket disposed on the tip side of the lead plate.

9. The battery module according to claim 7 or 8, wherein the cooling jacket includes a second cooling jacket disposed along both sides of the lead plate along the end portion.

10. The battery module according to claim 1, wherein the battery module further includes a heat insulating member covering the cooling jacket.

Images