Battery module

Abstract

The battery module (1A) comprises: a plurality of battery cells (20a to 20d) that are layered with each other; an electrically insulating heat transfer member (40a, 40b) that covers the periphery of the positive and negative electrode tabs (21a to 21d, 22a to 22d) of the plurality of battery cells (20a to 20d); and a cooling jacket (50a, 50b) that is in contact with a heat transfer member (40a, 40b) and that has an internal space (51) in which a refrigerant (R) flows.

Description

[Technical Field]

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

[0002] There is known an electric storage device having a cell stack in which electric storage cells are stacked, a bus bar connected to the tabs of the electric storage cells, and a tubular flow path formed along the bus bar (for example, see Patent Document 1). In this electric storage device, the bus bar is cooled or heated by circulating a heat medium through the flow path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-24886 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the storage cells of the above-mentioned conventional technology, the cooling flow path is in linear contact with the bus bar of the storage cell, and the thermal conduction efficiency between the flow path and the bus bar is poor, resulting in a problem of reduced cooling efficiency of the battery cell.

[0005] An object of the present invention is to provide a battery module that can improve the cooling efficiency of battery cells. [Means for solving the problem]

[0006] The present invention solves the above problem by providing a heat transfer member that has electrical insulation and that directly contacts and covers the periphery of the tabs of multiple battery cells, and a cooling jacket that has an internal space for refrigerant to flow and that is in contact with the heat transfer member, and by bringing the heat transfer member into direct contact with the tip surface and outer peripheral surface of the tabs. [Effects of the Invention]

[0007] According to the present invention, by covering the periphery of the tab of the battery cell with a heat transfer member and bringing a cooling jacket into contact with the heat transfer member, the efficiency of heat conduction between the tab and the heat transfer member can be improved, thereby improving the cooling efficiency of the battery cell. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing an example of the configuration of a battery module according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is a cross-sectional view showing an example of the configuration of a battery module according to a first modification. [Figure 4] FIG. 4 is a plan view showing an example of the configuration of a battery module according to a second modification. [Figure 5] FIG. 5 is a plan view showing an example of the configuration of a battery module according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] A battery module 1A according to this embodiment will be described with reference to the drawings. Fig. 1 is a perspective view showing an example of the configuration of the battery module 1A according to this embodiment, and Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1.

[0010] As shown in Figures 1 and 2, the battery module 1A in this embodiment includes a battery case 10, a plurality of battery cells 20a to 20d (see 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.

[0011] The battery case 10 accommodates the battery cells 20a to 20d inside. As shown in FIG. 1, the battery case 10 has a case body 11 and a lid member 12. The case body 11 has a box shape with an open top and both ends. The battery cells 20a to 20d are accommodated inside the case body 11. The lid member 12 closes the opening at the top end of the case body 11.

[0012] As shown in FIG. 2, the battery cells 20a to 20d have a flat shape and are stacked one on top of another along the Z direction in the figure. The battery cells 20a to 20d are secondary batteries such as lithium ion secondary batteries. Although not specifically shown, these secondary batteries include a positive electrode, an electrolyte, and a negative electrode. The electrolyte may be a liquid electrolyte or a solid electrolyte. The shape of the battery cells 20a to 20d is not limited to the above.

[0013] The battery cells 20a to 20d further have metallic positive electrode tabs 21a to 21d connected to the positive electrodes, and metallic negative electrode tabs 22a to 22d connected to the negative electrodes. 21c and negative electrode tabs 22b and 22d extends from the first end 23a of the battery cells 20a to 20d, while the negative electrode tab 22a , 22c and positive electrode tabs 21b, 21d The positive electrode tabs 21a to 21d and the negative electrode tabs 22a to 22d extend from a second end 23b different from the first end 23a. The positive electrode tabs 21a to 21d and the negative electrode tabs 22a to 22d are exposed to the battery case 10 at openings on both ends of the case body 11 of the battery case 10.

[0014] The positive electrode tab 21a of the battery cell 20a is connected to the metal bus bar 30a by welding, etc. One main surface (the lower surface in this example) of the positive electrode tab 21a is in contact with the heat transfer member 40a, while the other main surface (the upper surface in this example) of the positive electrode tab 21a is exposed from the heat transfer member 40a.

[0015] The negative electrode tab 22a of the battery cell 20a and the positive electrode tab 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. The negative electrode tab 22b of the battery cell 20b and the positive electrode tab 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. The negative electrode tab 22c of the battery cell 20c and the positive electrode tab 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. 40b and are connected to each other by welding or the like.

[0016] On the other hand, the negative electrode tab 22d of the battery cell 20d is connected to the metal bus bar 30b by welding, etc. The other main surface (the upper surface in this example) of the negative electrode tab 22d is in contact with the heat transfer member 40a. negative One main surface (the lower surface in this example) of the pole tab 22d is exposed from the heat transfer member 40a.

[0017] As described above, in this embodiment, the stacked battery cells 20a-20d are electrically connected in series, and their upper and lower ends are connected to the bus bars 30a, 30b, respectively. Note that the battery cells 20a-20d do not have to be electrically connected in series, and may be electrically connected in parallel. Also, in this embodiment, the positive electrode tabs 21b-21d and the negative electrode tabs 22a-22c are directly connected to each other, but this is not limiting and they may be electrically connected via bus bars.

[0018] The heat transfer members 40a, 40b cover both side surfaces of the battery cells 20a-20d and cover the peripheries of the positive electrode tabs 21a-21d and the negative electrode tabs 22a-22d. In this embodiment, the widths of the heat transfer members 40a, 40b are smaller than the widths of the first and second ends 23a, 23b of the battery cells 20a-20d.

[0019] The heat transfer members 40a, 40b are made of a material that is electrically insulating and has a relatively high thermal conductivity. The thermal conductivity of the heat transfer members 40a, 40b may be, for example, 1 to 10 W / mK. The heat transfer members 40a, 40b can be produced, for example, by molding a resin containing a filler or the like onto the side surfaces of the battery cells 20a to 20d. Examples of the filler include fibrous or particulate silicon.

[0020] 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, parts of the main surfaces of the bus bars 30a and 30b are in contact with the heat transfer member 40a, but this is not limiting, and parts of the bus bars 30a and 30b may be embedded in the heat transfer member 40a.

[0021] A pair of cooling jackets 50a, 50b are provided on the outside of the heat transfer members 40a, 40b. As shown in Fig. 1, the cooling jacket 50a has a rectangular parallelepiped shape with approximately the same width as the heat transfer member 40a and is in surface contact with the heat transfer member 40a. Similarly, the cooling jacket 50b has approximately the same width as the heat transfer member 40b and is in surface contact with the heat transfer member 40b. The cooling jackets 50a, 50b in this embodiment correspond to an example of a "first cooling jacket" in the present invention.

[0022] The cooling jackets 50a, 50b are cooling sources that cool the battery cells 20a-20d via the heat transfer members 40a, 40b. The cooling jackets 50a, 50b are made of, for example, a laminate film having an insulating layer and a metal layer, and in this case, an insulating layer such as a resin layer can be formed on the surface of the metal layer.

[0023] The cooling jackets 50a, 50b include an internal space 51 through which a refrigerant R flows. Note that the refrigerant may be any fluid capable of cooling the battery cells 20a to 20d, and may be either a liquid or a gas.

[0024] In this embodiment, the cooling jackets 50a, 50b each have parallel portions 52, 52 extending along a first direction that is substantially parallel to the stacking direction of the battery cells 20a-20d (the Z direction in the figure). Therefore, in the parallel portions 52, the internal space 51 also extends along the first direction, and the refrigerant R also flows along the first direction. Although not specifically shown, the cooling jackets 50a, 50b may be connected to devices such as a pump or a radiator via a flow path.

[0025] Heat insulating members 60a, 60b are provided on the outside of the parallel portions 52 of the cooling jackets 50a, 50b. In this embodiment, the heat insulating members 60a, 60b cover the outer surfaces of the heat transfer members 40a, 40b and the cooling jackets 50a, 50b. The heat insulating members 60a, 60b have a shape that conforms to the outer surfaces of the heat transfer members 40a, 40b and the cooling jackets 50a, 50b. In a state has a U-shape in plan view, and is curved so as to protrude toward the outside of the battery module 1A.

[0026] The heat insulating members 60a, 60b are made of a material having heat insulating properties. The heat insulating material is not particularly limited, but examples thereof include a resin material having heat insulating properties. More specifically, an example of a resin material having heat insulating properties is a foamed resin such as urethane foam. Such heat insulating members 60a, 60b can concentrate heat transferred from the positive and negative electrode tabs 21a-21d, 22a-22d to the cooling jackets 50a, 50b, thereby improving the heat dissipation effect.

[0027] In the battery module 1A of the present embodiment as described above, the heat transfer members 40a, 40b cover the peripheries of the positive and negative electrode tabs 21a-21d, 22a-22d of the battery cells 20a-20d, and the cooling jackets 50a, 50b are brought into contact with the heat transfer members 40a, 40b, thereby improving the efficiency of heat conduction between the positive and negative electrode tabs 21a-21d, 22a-22d and the heat transfer members 40a, 40b, and thereby improving the cooling efficiency (heat removal effect) of the battery cells 20a-20d.

[0028] Furthermore, with this battery module 1A, the cooling efficiency can be improved by the heat transfer members 40a, 40b, eliminating the need to enlarge the cooling mechanisms such as the cooling jackets 50a, 50b, and achieving energy savings. As a result, the volumetric energy density, weight energy density, required power, and required cost can be satisfied.

[0029] In particular, in this embodiment, the heat transfer members 40a, 40b and the positive and negative electrode tabs 21a to 21d, 22a to 22d are in three-dimensional contact with each other, which improves the thermal conductivity between the heat transfer members 40a, 40b and the positive and negative electrode tabs 21a to 21d, 22a to 22d, thereby improving the cooling efficiency of the battery cells 20a to 20d.

[0030] Furthermore, in this embodiment, the positive and negative electrode tabs 21a-21d, 22a-22d are cooled rather than directly cooling the main body portions (electrode stack portions) of the battery cells 20a-20d. According to the inventor's knowledge, the positive and negative electrode tabs 21a-21d, 22a-22d are more likely to reach higher temperatures than the main body portions of the battery cells 20a-20d, and therefore the battery module 1A in this embodiment can reduce the risk of temperature rise in the positive and negative electrode tabs 21a-21d, 22a-22d.

[0031] In the above embodiment, the cooling jackets 50a, 50b have the parallel portion 52 extending in the first direction (Z direction in the figure), but this is not limiting. For example, as in the following first modified example, the cooling jackets 50c, 50d may have vertical portions 53a to 53e extending along a second direction that is substantially perpendicular to the first direction.

[0032] 3 is a cross-sectional view showing an example of the configuration of a battery module 1B according to the first modification. As shown in FIG. 3, the battery module 1B of this modification has the following features compared to the battery module 1A of the above embodiment: (1) a cooling jacket 50c,50dThe battery module 1B of the first modification has vertical portions 53a-53e extending along the second direction (Y direction in the figure). However, the other configurations are the same as those of the above embodiment. Below, only the differences between the battery module 1B of the first modification and the above embodiment will be described, and the same components as those of the above embodiment will be assigned the same reference numerals and will not be described again.

[0033] In the first modified example, the cooling jacket 50c has tubular vertical portions 53a and 53b. The vertical portions 53a and 53b extend along the second direction (the Y direction in the figure). The vertical portion 53a is embedded in the heat transfer member 40a so as to be located between the positive electrode tab 21a and the negative electrode tab 22b. Meanwhile, the vertical portion 53b is embedded in the heat transfer member 40a so as to be located between the positive electrode tab 21c and the negative electrode tab 22d. Although not particularly shown, the cooling jacket 50c has a serpentine shape in which the vertical portions 53a and 53b are located between the positive electrode tab 21a and the negative electrode tab 22b and between the positive electrode tab 21c and the negative electrode tab 22d, and the vertical portions 53a and 53b are connected to each other via curved portions of the serpentine shape. The vertical portions 53a and 53b may be separate members.

[0034] 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 tab 22a, and a portion 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 tab 21b and the negative electrode tab 22c. The vertical portion 53e is located below the positive electrode tab 21d, and a portion of the vertical portion 53e is exposed from the heat transfer member 40b. Although not particularly shown, the cooling jacket 50d also has a serpentine shape, and the vertical portions 53c to 53e are connected to each other via curved portions of the serpentine shape. The vertical portions 53c to 53e may be separate bodies.

[0035] The battery module 1B in this first modified example can also improve the cooling efficiency, similar to the battery module 1A in the above embodiment.

[0036] In particular, in this modification, the cooling jackets 50c and 50d are embedded in the heat transfer members 40a and 40b, so the distance between the cooling jackets 50c and 50d and the positive and negative electrode tabs 21a to 21d and 22a to 22d can be reduced, thereby improving the cooling efficiency.

[0037] In the above embodiment, the cooling jackets 50a, 50b are provided only on the tip ends 24 of the positive and negative electrode tabs 21a to 21d, 22a to 22d, but this is not limiting. For example, as in the following second modified example, cooling jackets 50e to 50h may be further provided.

[0038] 4 is a plan view showing an example of the configuration of a battery module 1C according to Modification 2. Hereinafter, only the differences between the battery module 1C according to Modification 2 and the battery module 1A according to the above embodiment will be described, and the same components as those in the battery module 1A will be assigned the same reference numerals and will not be described again.

[0039] In the second modified example, cooling jackets 50e, 50f are provided on both sides of the positive and negative electrode tabs 21a, 22b, 21c, and 22d along the first ends 23a of the battery cells 20a to 20d. The cooling jackets 50e, 50f have parallel portions 52, similar to the above embodiment. However, the parallel portions 52 of the cooling jackets 50e, 50f have a width corresponding to the side surfaces of the positive and negative electrode tabs 21a, 22b, 21c, and 22d, and are narrower than the width of the parallel portions 52 of the cooling jacket 50a.

[0040] Similarly, the cooling jackets 50g and 50h are provided on both sides of the positive and negative electrode tabs 22a, 21b, 22c, and 21d along the second ends 23b of the battery cells 20a to 20d. The cooling jackets 50g and 50h also have parallel portions 52, similar to the cooling jackets 50e and 50f.

[0041] In this embodiment, the cooling jackets 50a, 50b, 50e Although the heat transfer members 40a and 40b are embedded in the heat transfer members 40a and 40b, the present invention is not limited to this and the heat transfer members 40a and 40b may be in contact with the heat transfer members 40a and 40b from the outside.

[0042] The battery module 1C in this second modified example can also improve the cooling efficiency, similar to the battery module 1A in the above embodiment. In particular, in this modified example, the cooling efficiency can be further improved by increasing the number of cooling jackets.

[0043] In the above embodiment, the positive and negative electrode tabs extend from the first end and the second end, but this is not limiting. As in the third modified example below, the positive and negative electrode tabs may extend from the same end (the second end 23b in the modified example below).

[0044] In this case, the cooling jacket 50a is also embedded in and in contact with the heat transfer member 40b. In this third modified example, cooling jackets 50i and 50j are provided on both sides of the positive and negative electrode tabs 21a, 22b, 21c, and 22d, and cooling jackets 50j and 50k are provided on both sides of the positive and negative electrode tabs 22a, 21b, 22c, and 21d. The cooling jackets 50i to 50k in this modified example have the same configuration as the cooling jackets 50e to 50h in the second modified example.

[0045] The battery module 1D in this third modification can also improve the cooling efficiency, similar to the battery module 1A in the above embodiment. In particular, in this modification, the cooling efficiency can be further improved by increasing the number of cooling jackets, similar to the second modification. [Explanation of symbols]

[0046] 1A,...Battery module 10...Battery case 11...Case body 12...Cover member 20a~20d...Battery cells 21a~21d...Positive electrode tab 22a~22d...Negative electrode tabs 23a, 23b...first and second ends 24...Tip 30a, 30b...bus bar 40a, 40b...heat transfer members 50a~50d...Cooling jacket 51...Interior space 52...Parallel section 53a~53d…Vertical part 60a, 60b...heat insulating members R...refrigerant

Claims

1. a plurality of battery cells stacked on top of one another; a heat transfer member that has electrical insulation and that directly contacts and covers the periphery of the tabs of the plurality of battery cells; a cooling jacket having an internal space through which a refrigerant flows and in contact with the heat transfer member; The tab includes a distal end surface and an outer peripheral surface, The heat transfer member is in direct contact with the tip surface and the outer circumferential surface of the battery module.

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

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

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

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

6. The battery module according to claim 5 , The cooling jacket is positioned between the plurality of tabs in the battery module.

7. The battery module according to claim 1 , The tabs include a positive electrode tab and a negative electrode tab, The positive electrode tab and the negative electrode tab may extend from the same end of the battery cell, or may extend from different ends of the battery cell.

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

9. The battery module according to claim 7 or 8, The battery module includes a second cooling jacket on both sides of the tab along the edge in a second direction substantially perpendicular to the stacking direction of the plurality of battery cells.

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

11. The battery module according to any one of claims 1 to 3, The tab is embedded in the heat transfer member.

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