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EP-4131576-B1 - BATTERY PACK

EP4131576B1EP 4131576 B1EP4131576 B1EP 4131576B1EP-4131576-B1

Inventors

  • SHIMIZU KEISUKE
  • ISHIZAKA Katsushi
  • MURAYAMA Chifumi

Dates

Publication Date
20260506
Application Date
20210330

Claims (20)

  1. A battery pack (10) that houses a secondary battery (14) inside a case (12), comprising: an exhaust part, by means of which an internal space of the case (12) where the secondary battery (14) is housed is in communication with outside, and which allows a gas discharged from the secondary battery (14) to be discharged from the internal space to the outside; and a heat exchanger (24), which is provided at the exhaust part and formed of a porous material having a three-dimensional mesh structure, and through which the gas passes, and the heat exchanger (34) comprises a shielding portion (36) that blocks pores located at an inner surface of the porous material facing the internal space, wherein in the porous material, pores at a surface located opposite to a surface on which the shielding portion (36) is provided are blocked.
  2. The battery pack (10) according to claim 1, wherein assuming that a predetermined direction is a first direction, the heat exchanger (24) comprises a high-density portion (26) having a size in the first direction that is smaller than that of a remaining portion (26) and having a density higher than that of the remaining portion, and the high-density portion is fixed to the case (12), and the heat exchanger (24) comprises a foam metal member.
  3. The battery pack (10) according to claim 2, wherein the exhaust part comprises an exhaust port (22) that opens to the outside of the case (12), and the heat exchanger (24) is fixed to the case (12) in a manner blocking the exhaust port (22).
  4. The battery pack (10) according to claim 2, wherein the exhaust part comprises an exhaust port (22) that opens to the outside of the case (12), and a duct portion connecting between the exhaust port (22) and the internal space; and the heat exchanger (24) is fixed to the case (12) in a manner blocking the duct portion.
  5. The battery pack (10) according to claim 2, wherein the high-density portion (26) is provided at peripheral parts of a pair of end faces in the first direction.
  6. The battery pack (10) according to claim 2, wherein the high-density portion (26) is provided along an entire perimeter of a peripheral part of the heat exchanger (24).
  7. The battery pack (10) according to claim 2, wherein at an end face, in the first direction, of the heat exchanger (24), the high-density portion (26) is provided at a position inward from a peripheral part.
  8. The battery pack (10) according to claim 2, wherein the high-density portion (26) is provided along an entire perimeter of a peripheral part of the heat exchanger (24), and an inward segment of the high-density portion (26) is further provided, which has two ends connected to the peripheral high-density portion (26).
  9. The battery pack (10) according to claim 2, wherein the case (12) covers an end face, in the first direction, of the high-density portion (26).
  10. The battery pack (10) according to claim 1, wherein the shielding portion (36) is formed on the inner surface at a position facing the exhaust port.
  11. The battery pack (10) according to claim 1, wherein the shielding portion (36) is a non-porous plate that covers a surface of the porous material.
  12. The battery pack (10) according to claim 1, wherein the shielding portion (36) is a filler received in the pores of the porous material.
  13. The battery pack (10) according to claim 1, wherein the shielding portion (36) is formed by fusing together skeleton parts that constitute the three-dimensional mesh structure in the porous material.
  14. The battery pack (10) according to claim 1, wherein the porous material is sheet-like, and the shielding portion (36) is formed on a surface located at one end, in a thickness direction, of the porous material.
  15. The battery pack (10) according to claim 1, wherein the porous material has, at a face located opposite to a surface on which the shielding portion (36) is formed, a region in which pores are blocked, and at least a part of the region in which the pores are blocked overlaps the shielding portion (36).
  16. The battery pack (10) according to claim 1, wherein at least one recess (46) is formed in a surface of the heat exchanger (44) facing the internal space.
  17. The battery pack (10) according to claim 16, wherein the at least one recess (46) has an opening size of 1 mm or more and a depth of 1 mm or more.
  18. The battery pack (10) according to claim 16 or 17, wherein when the surface is viewed from the internal space side, a ratio of an area of the at least one recess (46) to an area of the surface is 10 to 50 %.
  19. The battery pack (10) according to any one of claims 16 to 18, wherein a bottom part of the at least one recess (46) is wider than an entrance of the at least one recess (46).
  20. The battery pack (10) according to any one of claims 16 to 18, wherein a tip of a wall portion located between recesses (46), which correspond to the at least one recess (46), is chamfered.

Description

TECHNICAL FIELD The present disclosure relates to a battery pack that houses a secondary battery. BACKGROUND A secondary battery such as a lithium-ion battery is used in the form of a battery pack (also referred to as a battery module) in which a plurality of batteries are electrically connected and housed in a case. When there is an abnormality in a battery in such a battery pack, flammable high-temperature gas is generated from the battery. The battery has a safety valve, from which the generated gas is discharged into the battery pack. The battery pack has an exhaust gas duct connected to an exhaust port, via which the gas is discharged to the outside. Here, if the high-temperature flammable gas is discharged to the outside of the battery pack as it is, problems may occur. Patent Literature 1 discloses providing a foam (heat exchanger) made of metal, resin, or the like at the exhaust port, and lowering the gas temperature by causing the exhaust gas to pass therethrough. CITATION LIST PATENT LITERATURE PATENT LITERATURE 1: Japanese Unexamined Patent Application Publication No. H3-134952PATENT LITERATURE 2: US2016/104923PATENT LITERATURE 3: US2018/269448 SUMMARY TECHNICAL PROBLEM There is a need to further enhance the reliability of the above-described battery pack that uses a heat exchanger. The present disclosure provides a battery pack in which reliability can be enhanced. SOLUTION TO PROBLEM A battery pack according to the present disclosure is a battery pack that houses a secondary battery inside a case, including: an exhaust part, by means of which an internal space of the case where the secondary battery is housed is in communication with outside, and which allows a gas discharged from the secondary battery to be discharged from the internal space to the outside; and a heat exchanger, which is provided at the exhaust part and formed of a porous material having a three-dimensional mesh structure, and through which the gas passes. ADVANTAGEOUS EFFECTS OF INVENTION According to the present disclosure, the reliability of the battery pack can be further enhanced. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram showing an overall configuration of a battery pack according to an example embodiment.FIG. 2 is a diagram showing cross section A-A in FIG. 1.FIG. 3A is a plan view showing an example heat exchanger.FIG. 3B is a cross-sectional view of the heat exchanger, which is taken along cutting line B-B in FIG. 3A.FIG. 4A is a diagram illustrating a configuration for fixing the heat exchanger to a case.FIG. 4B is a cross-sectional view of the configuration for fixing the heat exchanger to the case, which is taken along cutting line B-B in FIG. 4A.FIG. 5 is a diagram showing an overall configuration of a battery pack according to another example embodiment.FIG. 6A is a plan view of another example heat exchanger.FIG. 6B is a diagram showing cross section C-C of the heat exchanger in FIG. 6A.FIG. 7A is a plan view of another example heat exchanger.FIG. 7B is a diagram showing cross section C-C of the heat exchanger in FIG. 7A.FIG. 8 is a diagram showing an overall configuration of a battery pack according to another example embodiment.FIG. 9 is a plan view of another example heat exchanger.FIG. 10A is a cross-sectional view showing an example shape of recesses formed in a heat exchanger.FIG. 10B is a cross-sectional view showing another example shape of the recesses.FIG. 10C is a cross-sectional view showing an example in which tips of wall portions (or projections) located between adjacent recesses in a heat exchanger are chamfered in a round shape. DESCRIPTION OF EMBODIMENTS Embodiments of the present disclosure will now be described by reference to the drawings. It should be noted that the present disclosure is not limited to the embodiments described herein. In the following, equivalent elements in all drawings are described by being labeled with the same reference numerals. Further, in the description given by the present text, reference numerals mentioned earlier shall be used again as necessary. (Overall Configuration of Battery Pack) FIG. 1 is a diagram showing an overall configuration of a battery pack 10 according to an example embodiment. The battery pack 10 has a box-shaped case 12, and a plurality of batteries 14, the number of which is four in this example, are housed in the case 12. Each battery 14 is a secondary battery, and, for example, a non-aqueous electrolyte secondary battery such as a lithium ion battery is used as the battery 14. The battery 14 has, for example, a cylindrical shape, and has a positive electrode terminal and a negative electrode terminal at respective ends thereof. For example, the battery 14 has an electrode assembly including a positive electrode and a negative electrode, and an outer can that houses the electrode assembly together with an electrolyte. The opening of the outer can may be sealed using a sealing plate together with an insulating gasket. In this case, th