Battery module

Abstract

To allow battery cells to be efficiently cooled.SOLUTION: A battery module includes a plurality of battery cells, at least one bus bar, and a cooling member. The bus bar electrically connects electrodes of the plurality of battery cells to each other. The cooling member contacts, in a heat transferable manner, the back side of portions of the bus bar that contact the electrodes. According to this configuration, the heat transferred from the electrodes of the battery cells to the bus bar can be dissipated to the cooling member on the back side of the electrodes. Therefore, the battery cells can be efficiently cooled.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a battery module including a plurality of battery cells. [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 battery modules installed in electric vehicles and the like include multiple battery cells and bus bars that electrically connect the electrodes of the battery cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-271063 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to enable efficient cooling of battery cells in such a battery module. [Means for solving the problem]

[0005] The present inventors discovered that battery cells can be efficiently cooled by contacting a cooling member to the rear side of the bus bar at the portion where the bus bar contacts the electrode, and arrived at the present invention. The present invention relates to the following battery modules (1) to (10).

[0006] (1) a plurality of battery cells; one or more bus bars that electrically connect the electrodes of the plurality of battery cells to each other; a cooling member that is in heat-transferable contact with a rear side of a portion of the bus bar that is in contact with the electrode; A battery module comprising:

[0007] With this configuration, heat transferred from the electrodes of the battery cells to the bus bars can be dissipated to the cooling member on the back side of the electrodes, thereby allowing the battery cells to be cooled efficiently.

[0008] (2) An insertion portion is provided on the back side of the portion of the bus bar that contacts the electrode, the cooling member has a protrusion that is inserted into the insertion portion and abuts against a bottom of the insertion portion. The battery module according to (1) above.

[0009] With this configuration, the cooling member can be positioned relative to the busbar by inserting the protrusions of the cooling member into the recesses of the busbar. Furthermore, the protrusions of the cooling member abut the bottom of the insertion portion. Therefore, the protrusions of the cooling member abut the backside of the busbar at the portion that abuts the electrode. Therefore, heat transferred from the electrode to the busbar can be dissipated to the protrusions of the cooling member located on the backside of the electrode.

[0010] (3) The battery module according to (1) or (2), wherein the cooling member is made of rubber.

[0011] According to this configuration, variations in bus bar height can be absorbed within the elastic range of the rubber.

[0012] (4) a case that houses the battery cells, the bus bars, and the cooling member; a cover for covering the opening of the case, a surface of the cooling member opposite to the bus bar side abutting against a cover; The battery module according to (3) above.

[0013] With this configuration, heat dissipated from the electrodes to the cooling member via the bus bars can be further dissipated to the cover 30. This allows the battery cells to be cooled more efficiently.

[0014] (5) The battery module according to (3), wherein the cooling member is made of rubber having thermal conductivity and insulating properties.

[0015] According to this configuration, the cooling member can ensure heat transfer between the bus bar and the cover while also ensuring insulation between the bus bar and the cover.

[0016] (6) The battery module according to (5), wherein the rubber is EPDM rubber.

[0017] EPDM rubber has heat conductivity and insulation properties, so it can ensure heat conductivity between the bus bar and the cover while also ensuring insulation between the bus bar and the cover.

[0018] (7) A plurality of the bus bars are provided, a part of the cooling member is present between adjacent bus bars; The battery module according to (5) above.

[0019] According to this configuration, the cooling member can be used to ensure insulation between adjacent bus bars.

[0020] (8) A water jacket is attached to the outside of the cover, A refrigerant flows between the water jacket and the cover. The battery module according to (4) above.

[0021] With this configuration, the heat of the battery cells that is dissipated from the electrodes to the cover via the bus bars and cooling member can be further dissipated to the refrigerant, thereby allowing the battery cells to be cooled more efficiently.

[0022] (9) The bus bar and the cooling member have concave and convex shapes that fit together. The battery module according to (1) or (2).

[0023] This configuration prevents the cooling member from shifting position relative to the bus bar, thereby maintaining the cooling member in an optimal position relative to the bus bar and maximizing heat dissipation performance, thereby also allowing for efficient cooling of the battery cells.

[0024] (10) A plurality of battery cells; one or more bus bars that electrically connect the electrodes of the plurality of battery cells to each other; a cooling member that is in contact with the bus bar so as to be capable of transferring heat thereto; The bus bar and the cooling member have concave and convex shapes that fit together. Battery module.

[0025] This configuration also allows the battery cells to be cooled efficiently, similar to the case of (9) above. [Effects of the Invention]

[0026] As described above, the inventions (1) and (10) allow the battery cells to be cooled efficiently. Furthermore, the configurations (2) to (9) that cite the invention (1) provide additional effects. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 3 is a side cross-sectional view showing the battery module of the first embodiment, and more specifically, a cross-section taken along line II in FIG. 2. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along the line III-III in FIG. [Figure 4] FIG. 2 is an enlarged view of a part of FIG. [Figure 5] FIG. 2 is a perspective view showing a bus bar and a cooling member. [Figure 6] FIG. 2 is an exploded perspective view showing a bus bar and a cooling member. [Figure 7] FIG. 6 is a side cross-sectional view showing a battery module of a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0028] 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.

[0029] [First embodiment] As shown in FIG. 1, the battery module 100 includes a case 80, a plurality of battery cells 70, a plurality of bus bars 50, a plurality of cooling members 40, and a cover 30.

[0030] Hereinafter, as shown in Figure 2, two predetermined directions that intersect at right angles in a horizontal plane will be referred to as the "X direction" and the "Y direction." One of the X directions will be referred to as the "X- direction," and the opposite direction will be referred to as the "X+ direction." One of the Y directions will be referred to as the "Y- direction," and the opposite direction will be referred to as the "Y+ direction."

[0031] As shown in Fig. 1, the case 80 has a box shape that opens upward. The case 80 is made of a material such as metal. The case 80 houses the battery cells 70, the bus bars 50, and the cooling members 40. The cover 30 covers the opening of the case 80.

[0032] As shown in Figure 3, each battery cell 70 has a rectangular exterior that is elongated in the X direction. Hereinafter, a stack of multiple battery cells 70 stacked in the Y direction will be referred to as a "battery stack Bs." The case 80 houses two battery stacks Bs lined up in the X direction. In each battery stack Bs, a separator 79 is disposed between every two battery cells 70 lined up in the Y direction. The separator 79 is made of a material such as resin.

[0033] 3, each battery cell 70 has a positive electrode p at one end in the X direction on the upper surface of the exterior, and a negative electrode n at the other end in the X direction on the upper surface of the exterior casing 72. Specifically, for a predetermined number of battery cells 70, the positive electrode p is arranged on the X-direction side, and the negative electrode n is arranged on the X+ direction side. On the other hand, for the other battery cells 70, the negative electrode n is arranged on the X-direction side, and the positive electrode p is arranged on the X+ direction side.

[0034] 2, most of the bus bars 50 electrically connect the electrodes p, n of the battery cells 70 adjacent in the X direction or the Y direction. On the other hand, a given bus bar 50 electrically connects the positive electrode p of the electrically most positive battery cell 70 to the positive electrode P of the entire battery module 100. Furthermore, another bus bar 50 electrically connects the negative electrode n of the electrically most negative battery cell 70 to the negative electrode N of the entire battery module 100. As described above, in this embodiment, all of the battery cells 70 in the battery module 100 are connected in series.

[0035] 6, each bus bar 50 is formed by, for example, bending a single metal plate. An inserted portion 55 is provided on each bus bar 50 directly above the portion that abuts against electrodes p and n.

[0036] Specifically, as shown in FIG. 4 , each busbar 50 has a busbar base 52 and a return portion 54. The busbar base 52 is plate-shaped and extends in the X and Y directions. A return portion 54 is provided for each electrode p, n. For example, as shown in FIG. 4 , each return portion 54 may have a shape that extends downward from the Y-direction end of the busbar base 52 and then inward in the Y direction, or a different shape that extends downward from the X-direction end and then inward in the X direction. The return portions 54 are welded to the electrodes p, n. A through hole 53 is formed in the busbar base 52 in a portion located directly above the electrodes p, n. The portion from the through hole 53 to the return portion 54 constitutes the inserted portion 55. Therefore, the back surface of the return portion 54 at the portion that abuts against the electrodes p, n constitutes the bottom surface of the inserted portion 55.

[0037] 1, a cooling member 40 is provided for each bus bar 50. Each cooling member 40 is in contact with the upper surface of the bus bar 50 corresponding to that cooling member 40 so as to be able to transfer heat. Each cooling member 40 is made of rubber having heat conductivity and insulating properties, and more specifically, is made of EPDM rubber (ethylene propylene diene rubber).

[0038] As shown in FIG. 6, each cooling member 40 has a cooling member base 42, an insulating portion 47, and a protrusion 45. As shown in FIG. 5, the cooling member base 42 is plate-shaped and extends in the X and Y directions. The insulating portions 47 protrude downward from both ends of the cooling member base 42 in the Y direction. As shown in FIG. 4, a protrusion 45 is provided for each of the electrodes p and n. Each protrusion 45 protrudes downward from the cooling member base 42. Each protrusion 45 is inserted into a corresponding insertion portion 55 and abuts against the bottom of the insertion portion 55.

[0039] 5, the insulating portion 47 on the Y+ side of each cooling member 40 abuts against the Y+-side end of the bus bar 50 from the Y+ direction. The insulating portion 47 on the Y- side of each cooling member 40 abuts against the Y-side end of the bus bar 50 from the Y- direction. As a result, insulating portions 47, which are part of the cooling member 40, are present between bus bars 50 adjacent to each other in the Y direction. As shown in FIG. 4, the upper surface of the cooling member base 42 abuts against the lower surface of the cover 30.

[0040] With the above configuration, as shown in FIG. 4, heat from each battery cell 70 is dissipated from the electrodes p and n to the cover 30 via the bus bar 50 and the cooling member 40.

[0041] The configuration and effects of this embodiment are summarized below.

[0042] 4, the cooling member 40 is in heat-transferable contact with the rear side of the bus bar 50 at the portion that contacts the electrodes p and n. This allows heat transferred from the electrodes p and n of the battery cells 70 to the bus bar 50 to be dissipated to the cooling member 40 located on the rear side of the electrodes p and n. This allows the battery cells 70 to be cooled efficiently.

[0043] Inserted portions 55 are provided on the back side of the portions of busbar 50 that come into contact with electrodes p and n. Protrusions 45 of cooling member 40 are inserted into inserted portions 55. This allows cooling member 40 to be positioned relative to busbar 50. Furthermore, protrusions 45 of cooling member 40 come into contact with the bottom of inserted portions 55, i.e., the back side of the portions of busbar 50 that come into contact with electrodes p and n. This allows heat transferred from electrodes p and n to busbar 50 to be dissipated to protrusions 45 of cooling member 40 that are located on the back side of electrodes p and n.

[0044] Cooling member 40 is made of rubber, and therefore can absorb variations in height of bus bars 50 within the elastic range of rubber.

[0045] The top surface of the cooling member 40, i.e., the surface of the cooling member 40 opposite the bus bar 50 side, abuts against the cover 30. Therefore, heat dissipated from the electrodes p and n to the cooling member 40 via the bus bar 50 can be further dissipated to the cover 30. This allows the battery cells 70 to be cooled more efficiently.

[0046] Cooling member 40 is made of rubber that is heat-conductive and insulating, and therefore, cooling member 40 can ensure heat transfer between bus bar 50 and cover 30 while also ensuring insulation between bus bar 50 and cover 30.

[0047] More specifically, cooling member 40 is made of EPDM rubber. EPDM rubber has heat conductivity and insulation properties. Therefore, the EPDM rubber can ensure heat conductivity and insulation between bus bar 50 and cover 30.

[0048] Insulating portion 47, which is a part of cooling member 40, is present between adjacent bus bars 50. Therefore, insulation between adjacent bus bars 50 can be ensured by utilizing cooling member 40.

[0049] As shown in FIG. 6, the bus bar 50 is provided with an insertion portion 55. The cooling member 40 has protrusions 45 that are inserted into the insertion portion 55. In other words, the bus bar 50 and the cooling member 40 have concave and convex shapes that fit together. This prevents the cooling member 40 from shifting position relative to the bus bar 50. As a result, as shown in FIG. 4, the cooling member 40 can be held in an optimal position relative to the bus bar 50, maximizing heat dissipation performance. This also contributes to efficient cooling of the battery cells 70.

[0050] [Second embodiment] Next, a second embodiment will be described with reference to Fig. 7. This embodiment will be described based on the first embodiment, focusing on differences from the first embodiment, and descriptions of the same or similar aspects to the first embodiment will be omitted as appropriate.

[0051] 7, the water jacket 20 is attached above the cover 30, that is, outside the cover 30. The space between the water jacket 20 and the cover 30 forms a flow path Fp. A refrigerant Rf flows through the flow path Fp.

[0052] According to this embodiment, the refrigerant Rf flows between the water jacket 20 and the cover 30. Therefore, the heat of the battery cells 70 that is dissipated from the electrodes p and n to the cover 30 via the bus bars 50 and the cooling member 40 can be further dissipated to the refrigerant Rf. As a result, the battery cells 70 can be cooled even more efficiently.

[0053] [Other embodiments] The above-described embodiment can be modified, for example, as follows. The cooling member 40 shown in FIG. 4 may be made of rubber other than EPDM rubber. Specifically, it may be made of, for example, silicone rubber with good thermal conductivity. The case 80 shown in FIG. 3 may house only one battery stack Bs, or three or more. The case 80 shown in FIG. 2 may have multiple parallel-connected battery cells 70, each with a predetermined number of battery cells 70 (e.g., two or three), connected in series. Some of the multiple cooling members 40 may be integrally formed. In other words, one cooling member 40 may be provided to straddle multiple bus bars 50. [Explanation of symbols]

[0054] 20 Water Jacket 30 Cover 40 Cooling member 45 Protrusion (uneven shape) 47 Insulation part (part of cooling member) 50 busbar 55 Inserted part (uneven shape) 70 battery cells 80 cases 100 battery modules Fp flow path (between the water jacket and the cover) Rf refrigerant

Claims

1. A plurality of battery cells; one or more bus bars that electrically connect the electrodes of the plurality of battery cells to each other; a cooling member that is in heat-transferable contact with a rear side of a portion of the bus bar that is in contact with the electrode, an insertion portion is provided on a rear side of a portion of the bus bar that contacts the electrode, the cooling member has a protrusion that is inserted into the insertion portion and abuts against a bottom of the insertion portion. Battery module.

2. The battery module according to claim 1 , wherein the cooling member is made of rubber.

3. a case that houses the battery cells, the bus bars, and the cooling member; a cover for covering the opening of the case, a surface of the cooling member opposite to the bus bar side abutting against a cover; The battery module according to claim 1 or 2.

4. 3. The battery module according to claim 2, wherein the cooling member is made of rubber having thermal conductivity and insulating properties.

5. The battery module according to claim 4 , wherein the rubber is EPDM rubber.

6. A plurality of the bus bars are provided, a part of the cooling member is present between adjacent bus bars; The battery module according to claim 4 .

7. A water jacket is attached to the outside of the cover, A refrigerant flows between the water jacket and the cover. The battery module according to claim 3 .

8. The bus bar and the cooling member have concave and convex shapes that fit together. The battery module according to claim 1 or 2.

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