Battery pack and battery pack module

Abstract

Provided are: a battery pack having a plurality of pouch-type cells configured such that an electricity storage unit for storing charges and an electrolyte solution are sealed in an exterior material, the battery pack being capable of releasing internal pressure when the internal pressure of the pouch-type cells increases; and a battery pack module provided with the battery pack. A battery pack (100) has a plurality of pouch-type battery cells (4), and an intermediate plate (8) disposed so as to be sandwiched between the pouch-type battery cells (4). The pouch-type battery cell (4) has a power storage unit (5), an electrolyte solution (6), and an exterior material (7) that seals the electrolyte solution (6). The intermediate plate (8) is provided with protrusions (81) that pierce the exterior material (7) when the pouch-type battery cells (4) expand.

Description

Technical Field

[0001] This invention relates to a battery pack having multiple pouch-type battery cells, and a battery pack module having the battery pack. Background Technology

[0002] Conventionally, vehicles equipped with electric motors as a drive source have used secondary batteries such as lithium-ion batteries. Patent Document 1 describes a secondary battery module comprising multiple secondary batteries, a housing housing the multiple secondary batteries, a pressure plate forming holes for inserting electrode terminals of the secondary batteries, and a protective cover covering the pressure plate. The housing, pressure plate, and protective cover constitute a housing. The pressure plate is installed at the opening of the housing into which the multiple secondary batteries are inserted. Each secondary battery is equipped with an explosion-proof valve, which generates gas internally when the internal temperature rises, and ruptures to release the internal pressure when the internal pressure reaches a specified value. The pressure plate has a protrusion that punctures the explosion-proof valve when it expands due to internal pressure, thus preventing the explosion-proof valve from rupturing even when the internal pressure of the secondary battery reaches a specified value.

[0003] Furthermore, in recent years, for example as described in Patent Document 2, it has become possible to use pouch-type battery cells, in which the energy storage section including the positive electrode, negative electrode, and separator, along with the electrolyte, is sealed together with an outer casing material as a secondary battery for vehicles. The outer casing material is, for example, a pouch-shaped structure obtained by overlapping laminates and sealing the periphery by heat welding.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2008-270032

[0005] Patent Document 2: Japanese Patent Application Publication No. 2023-34053

[0006] In a battery pack consisting of multiple pouch-type battery cells arranged as described above, the periphery of the outer material is sealed by heat fusion, so the internal pressure cannot be released by the same structure as the housing described in Patent Document 1. Summary of the Invention

[0007] Therefore, the object of the present invention is to provide a battery pack having a plurality of pouch-type battery cells comprising a charge storage section and an electrolyte sealed together in an outer casing material, which can release internal pressure when the internal pressure of the pouch-type battery cells becomes high, and a battery pack module having the battery pack.

[0008] To achieve the above-mentioned objective, the present invention provides a battery pack having a plurality of pouch-type battery cells and an intermediate plate configured to be sandwiched between the pouch-type battery cells. Each pouch-type battery cell has an energy storage section, an electrolyte, and an outer casing material for sealing the electrolyte. A protrusion is provided on the intermediate plate, which punctures the outer casing material when the pouch-type battery cell expands.

[0009] In addition, in order to achieve the above-mentioned objective, the present invention provides a battery pack module, which includes the battery pack and a housing for housing the battery pack.

[0010] According to the battery pack and battery pack module of the present invention, when the internal pressure of the pouch battery cell becomes high, the internal pressure can be released by piercing the outer material through the protrusion of the middle plate. Attached Figure Description

[0011] Figure 1 This is an external view of a battery module according to an embodiment of the present invention.

[0012] Figure 2 yes Figure 1 A cross-sectional view at line AA.

[0013] Figure 3 yes Figure 1 A cross-sectional view at line BB.

[0014] Figure 4 This is a cross-sectional view showing the structure of a pouch cell.

[0015] Figure 5 This is an exploded 3D view of a battery pack.

[0016] Figure 6 It is a three-dimensional sectional view showing a portion of the battery pack.

[0017] Figure 7 This is a three-dimensional representation of the middle plate. Detailed Implementation

[0018] [Implementation Method]

[0019] Reference Figures 1 to 7 Embodiments of the present invention will be described below. Furthermore, the embodiments described below are preferred examples for carrying out the present invention. While various technically preferred aspects are also specifically illustrated, the scope of the present invention is not limited to these specific embodiments.

[0020] Figure 1 This is an external view of the battery module 1 according to an embodiment of the present invention. Figure 2 yes Figure 1 A cross-sectional view of the battery module 1 at line AA. Figure 3 yes Figure 1 A cross-sectional view of the battery module 1 at the BB line. The battery module 1 is used, for example, as a power source for a vehicle that has an electric motor as a driving source for propulsion.

[0021] The battery module 1 includes a housing 10, a battery pack 100 housed within the housing 10, first to fifth busbars 21 to 25, and a control circuit 3. The housing 10 is, for example, composed of first to third housing components 11 to 13, which are made of thermoplastic resin such as PBT (polybutylene terephthalate). The first housing component 11 and the second housing component 12, and the second housing component 12 and the third housing component 13 are respectively hermetically welded by laser welding.

[0022] A battery pack 100 is housed in the first housing component 11. Figure 1 In the diagram, the first housing component 11 is shown by a double-dotted line, and the battery pack 100 housed within it is shown by a solid line. The battery pack 100 has multiple pouch-type battery cells 4. The control circuitry 3 is housed in the second housing component 12.

[0023] The control circuit 3 monitors and controls the voltage, current, and temperature of each pouch cell 4, and communicates with a higher-level control device via a communication line connected to a connector 121 disposed on the second housing component 12. The control circuit 3 has a substrate 31 and multiple electronic components 32, such as ICs, resistors, and capacitors, mounted on the substrate 31. The substrate 31 is fixed to the second housing component 12 by multiple bolts 14.

[0024] like Figure 2 As shown, the second outer casing component 12 is provided with a connecting hole 120 that connects the internal space of the first outer casing component 11 with the internal space of the second outer casing component 12. The third outer casing component 13 is provided with a through hole 130, which is sealed by a cover 15. The cover 15 prevents foreign objects from entering the interior of the outer casing 10 through the through hole 130. When the pressure difference between the inside and outside of the outer casing 10 increases, air flows through the through hole 130, thus mitigating the pressure difference.

[0025] In this embodiment, the battery pack 100 has four pouch-type battery units 4. Each pouch-type battery unit 4 is a rechargeable and dischargeable secondary battery. Each pouch-type battery unit 4 has a positive electrode tab 401 and a negative electrode tab 402. The four pouch-type battery units 4 are... Figure 1 The cells are arranged in the direction indicated by the middle arrow C. This arrangement direction corresponds to the width direction of the first housing component 11. Hereinafter, in the case of specific description of each of the four pocket battery units 4, the four pocket battery units 4 will be referred to as the first to fourth pocket battery units 41 to 44. The positive electrode tab 401 and the negative electrode tab 402 of each of the first to fourth pocket battery units 41 to 44 are connected in series.

[0026] The positive electrode tab 401 of the first pocket-type battery unit 41 is connected to the first busbar 21. A second busbar 22 is connected to the connection point 4a between the negative electrode tab 402 of the first pocket-type battery unit 41 and the positive electrode tab 401 of the second pocket-type battery unit 42. A third busbar 23 is connected to the connection point 4b between the negative electrode tab 402 of the second pocket-type battery unit 42 and the positive electrode tab 401 of the third pocket-type battery unit 43. A fourth busbar 24 is connected to the connection point 4c between the negative electrode tab 402 of the third pocket-type battery unit 43 and the positive electrode tab 401 of the fourth pocket-type battery unit 44. The negative electrode tab 402 of the fourth pocket-type battery unit 44 is connected to the fifth busbar 25. The potentials of the first to fifth busbars 21 to 25 are input to the control circuit 3.

[0027] Figure 4 This is a schematic cross-sectional view illustrating a structural example of the pouch-type battery cell 4. The pouch-type battery cell 4 is a lithium-ion secondary battery that uses lithium ions as electrolyte ions, and more specifically, a lithium-ion capacitor.

[0028] The pouch-type battery cell 4 has a positive electrode tab 401 and a negative electrode tab 402, a charge storage section 5, an electrolyte 6 containing an organic solvent (non-aqueous solvent) and an electrolyte, and an outer casing material 7 for sealing the electrolyte 6. The charge storage section 5 has a plurality of positive electrode plates 51 and a plurality of negative electrode plates 52 arranged alternately, and a plurality of separators 53 disposed between the plurality of positive electrode plates 51 and negative electrode plates 52.

[0029] The positive electrode plate 51 has a thin plate-shaped current collector 511 and positive electrode active material layers 512 coated on both sides of the current collector 511. The positive electrode active material layer 512 includes a positive electrode active material with a large specific surface area and high conductivity, and a conductive additive for improving the conductivity of the positive electrode active material layer 512. The negative electrode plate 52 has a thin plate-shaped current collector 521 and a negative electrode active material layer 522 coated on both sides of the current collector 521. The negative electrode active material layer 522 has the ability to adsorb and release lithium ions (Li). + The negative electrode active material. In the negative electrode active material, lithium ions (Li) are pre-doped during manufacturing. + ).

[0030] Electrolyte 6, along with multiple positive electrode plates 51, multiple negative electrode plates 52, and multiple separators 53, is contained within an outer casing 7 and sealed inside the outer casing 7. Positive electrode tab 401 is electrically connected inside the outer casing 7 to the current collector 511 of each of the multiple positive electrode plates 51. Negative electrode tab 402 is electrically connected inside the outer casing 7 to the current collector 521 of each of the multiple negative electrode plates 52. A portion of both positive and negative electrode tabs 401 and 402 is exposed outside the outer casing 7. A thermosetting resin 70 is sandwiched between the positive and negative electrode tabs 401 and 402 and the outer casing 7.

[0031] The outer packaging material 7 is a laminated film comprising a core sheet 701, an inner sheet 702 bonded to the inner side of the core sheet 701, and an outer sheet 703 bonded to the outer side of the core sheet 701. The core sheet 701 is aluminum foil. The inner sheet 702 is a resin sheet such as polypropylene. The outer sheet 703 is a resin sheet such as nylon PET film.

[0032] Furthermore, the outer casing 7 has a surface portion 71 and a back portion 72 that separate the energy storage unit 5, and the surface portion 71 and the back portion 72 are thermally fused together at the periphery of the pouch-type battery cell 4. In the following description, the housing portion 7a of the outer casing 7 refers to the portion that houses the energy storage unit 5 and the electrolyte 6 together, and the peripheral sealing portion 7b of the outer casing 7 refers to the portion that is sealed in a manner that surrounds the housing portion 7a.

[0033] If the pouch-type battery cell 4 becomes overheated due to overcharging or over-discharging, the electrolyte 6 may vaporize and expand. Furthermore, if the expansion of the pouch-type battery cell 4 is too large, there is a concern that the outer casing 10 may be damaged. Therefore, the battery pack 100 of this embodiment has an intermediate plate 8, which is provided with a protrusion 81 that opens the outer casing 7 when the pouch-type battery cell 4 expands to release the internal pressure of the outer casing 7.

[0034] Figure 5 This is an exploded 3D view of battery pack 100. Figure 6 This is a three-dimensional sectional view showing a portion of the battery pack 100. Figure 7 This is a three-dimensional diagram representing the middle plate 8.

[0035] In this embodiment, intermediate plates 8 are respectively disposed between the first pouch battery unit 41 and the second pouch battery unit 42, and between the third pouch battery unit 43 and the second pouch battery unit 44. The intermediate plates 8 are, for example, injection-molded resin bodies. However, the intermediate plates 8 are not limited to being made of resin, and may also be made of metal, for example.

[0036] The intermediate plate 8 integrally comprises a flat plate portion 80, a plurality of protrusions 81 disposed on both sides of the flat plate portion 80, and a spacer holding portion 82 disposed at the end of the flat plate portion 80. The flat plate portion 80 is rectangular in size corresponding to the size of the pouch-type battery cell 4. The plurality of protrusions 81 are configured to protrude from one side 80a and the other side 80b of the flat plate portion 80 in the thickness direction of the flat plate portion 80. The front end portion 811 of each protrusion 81 (refer to...) Figure 7 The protrusion 81 is formed to be sharp enough to pierce the outer material 7. When the pouch battery cell 4 expands, the protrusion 81 pierces the outer material 7, thereby venting the gas generated inside the outer material 7 to the outside of the outer material 7, and preventing the outer material 7 from rupturing due to internal pressure.

[0037] The protrusions 81 are positioned opposite the peripheral sealing portion 7b of the outer casing material 7 in the arrangement direction of the plurality of pouch-type battery cells 4. More specifically, four protrusions 81 are provided on the intermediate plate 8 such that the front end 811 of each protrusion 81 is opposite the end of the receiving portion 7a side in the peripheral sealing portion 7b of the outer casing material 7.

[0038] On one side 80a of the flat plate 80, protrusions 81 are provided at two locations of the receiving portion 7a separated by the outer packaging material 7 in a direction parallel to the flat plate 80. Similarly, on the other side 80b of the flat plate 80, protrusions 81 are also provided at two locations of the receiving portion 7a separated by the outer packaging material in a direction parallel to the flat plate 80. Furthermore, the protrusions 81 in the intermediate plate 8 are not limited to this; one protrusion 81 may be provided on one side 80a and another side 80b of the flat plate 80, or three or more protrusions 81 may be provided. However, in order to reliably expel gas from the outer packaging material 7 when the pouch-type battery units 41-44 expand, it is preferable to provide protrusions 81 at least at two locations of the receiving portion 7a separated by the outer packaging material 7 on both sides of the flat plate 80.

[0039] In this embodiment, on one side 80a and the other side 80b of the flat plate portion 80, at a position 800 relative to the center of the flat plate portion 80 (refer to...) Figure 7 Two protrusions 81 are provided symmetrically, and the center position 800 of the flat plate 80 is parallel to the center of the receiving part 7a along the arrangement direction of the plurality of pouch-shaped battery units 4.

[0040] The spacer retaining portion 82 maintains the distance between the peripheral sealing portions 7b of the two pouch-type battery cells 4 sandwiched between the intermediate plate 8. More specifically, the spacer retaining portion 82 of one of the two intermediate plates 8 of the battery pack 100, configured to sandwich between the first pouch-type battery cell 41 and the second pouch-type battery cell 42, maintains the distance between the peripheral sealing portions 7b of the outer casing material 7 of the first pouch-type battery cell 41 and the peripheral sealing portions 7b of the outer casing material 7 of the second pouch-type battery cell 42. The spacer retaining portion 82 of the other intermediate plate 8, configured to sandwich between the third pouch-type battery cell 43 and the fourth pouch-type battery cell 44, maintains the distance between the peripheral sealing portions 7b of the outer casing material 7 of the third pouch-type battery cell 43 and the peripheral sealing portions 7b of the outer casing material 7 of the fourth pouch-type battery cell 44.

[0041] The spacer retaining portion 82 is located at a position further away from the receiving portion 7a of the outer material 7 than the protrusion 81. In this embodiment, spacer retaining portions 82 are provided at both ends in the long side direction of the rectangular flat plate portion 80. The spacer retaining portion 82, for example, prevents the front end portion 811 of the protrusion 81 from contacting the outer material 7 due to vibration.

[0042] One intermediate plate 8 is fixed to the first pouch-type battery unit 41, and the other intermediate plate 8 is fixed to the third pouch-type battery unit 43. In this embodiment, as... Figure 3 As shown, the flat portion 80 of one intermediate plate 8 is fixed to the outer material 7 of the first pouch-type battery unit 41 by double-sided tape 91, and the other intermediate plate 8 is fixed to the outer material 7 of the third pouch-type battery unit 43 by double-sided tape 92.

[0043] like Figure 2 as well as Figure 3 As shown, the first outer casing component 11 of the battery pack 100 is a cuboid shape having a bottom wall portion 110 and four side wall portions 111 to 114. The battery pack 100 is disposed between a pair of side wall portions 111 and 113 facing each other in the arrangement direction of the first to fourth pocket-type battery units 41 to 44. Sheet-shaped spacers 93 are disposed between the first pocket-type battery unit 41 and the side wall portion 111, between one intermediate plate 8 and the second pocket-type battery unit 42, between the second pocket-type battery unit 42 and the third pocket-type battery unit 43, between another intermediate plate 8 and the fourth pocket-type battery unit 44, and between the fourth pocket-type battery unit 44 and the side wall portion 113.

[0044] The support plate 94 supporting the first to fourth pouch-type battery units 41 to 44 is disposed at the bottom of the first housing component 11 in contact with the bottom wall portion 110. A groove is formed in the support plate 94, which accommodates a portion of the peripheral sealing portion 7b of the outer casing material 7 of each of the first to fourth pouch-type battery units 41 to 44.

[0045] Furthermore, in this embodiment, the battery pack 100 has four pouch-type battery units 4, but the number of pouch-type battery units 4 in the battery pack 100 is not limited to four, and the battery pack 100 may have more pouch-type battery units 4. When the battery pack 100 has four or more pouch-type battery units 4, when using N (N is a natural number) to represent the arrangement order of each pouch-type battery unit 4 in the arrangement direction, an intermediate plate 8 is arranged between the 2Nth and 2N-1th pouch-type battery units 4, and no intermediate plate 8 is arranged between the 2Nth and 2N+1th pouch-type battery units 4. Therefore, compared with the case where intermediate plates 8 are arranged between each pair of adjacent pouch-type battery units 4 in the arrangement direction, the number of intermediate plates 8 can be reduced, and the battery pack 100 can be miniaturized and made lighter.

[0046] Alternatively, the pouch-type battery unit 4 can be fixed to at least one of the 2Nth pouch-type battery unit 4 and the 2N-1th pouch-type battery unit 4. By fixing the intermediate plate 8 to the pouch-type battery unit 4, the position of the protrusion 81 relative to the outer casing material 7 of the pouch-type battery unit 4 can be appropriately maintained. The method of fixing the outer casing material 7 to the pouch-type battery unit 4 is not limited to the double-sided tapes 91 and 92 described above; for example, the intermediate plate 8 can also be bonded to the outer casing material 7 of the pouch-type battery unit 4.

[0047] [Effects of the Implementation Method]

[0048] According to the embodiment described above, when the internal pressure of the pouch battery cell 4 increases and the outer casing 7 expands, the outer casing 7 is pressed against the protrusion 81, creating an opening in the outer casing 7, allowing gas to be released. Therefore, even without an explosion-proof valve on the outer casing 7 that opens when the pressure of the pouch battery cell 4 increases, gas can still be released, thus reducing the cost of the battery pack 100. However, an explosion-proof valve can also be installed on the outer casing 7, and the intermediate plate 8 can be positioned adjacent to the pouch battery cell 4 to address situations where the explosion-proof valve fails to open for some reason. In this case, the reliability of the battery pack 100 is improved.

[0049] (Postscript)

[0050] The present invention has been described above based on embodiments, but these embodiments do not limit the invention to the technical solutions involved. Furthermore, it should be noted that not all combinations of features described in the embodiments are necessary for the method to solve the problem of the invention. Additionally, the present invention can be appropriately modified by omitting some components, or by adding or substituting components, without departing from its spirit. Furthermore, some components of the above-described embodiments can be combined with each other, and modifications can be made, for example, as described below.

[0051] In the above embodiments, the application of the present invention to lithium-ion capacitors that can be charged and discharged more quickly than ordinary lithium-ion batteries has been described, but it is not limited thereto. The present invention can also be applied to lithium-ion batteries and other types of secondary batteries. In addition, the battery module 1 and the battery pack 100 are not limited to automotive use and can be used for various applications.

[0052] Furthermore, in the above embodiment, the case where the battery pack 100 has four pouch-type battery units 4 has been described, but as a configuration of the battery pack 100, it is also possible to configure it such that an intermediate plate 8 is disposed between two pouch-type battery units 4.

[0053] Explanation of reference numerals in the attached figures

[0054] 1… Battery module; 10… Housing; 100… Battery pack; 4… Pocket battery cell; 5… Energy storage section; 6… Electrolyte; 7… Outer material; 7a… Reception section; 7b… Peripheral sealing section; 8… Intermediate plate; 80… Flat plate section; 81… Protrusion section; 82… Spacer retention section.

Claims

1. A battery pack having a plurality of pouch-type battery cells and an intermediate plate configured to be sandwiched between the pouch-type battery cells, wherein, The aforementioned pouch-type battery cell includes an energy storage section, an electrolyte, and an outer casing material for sealing the electrolyte. The intermediate plate is provided with a protrusion that punctures the outer material when the pouch-shaped battery cell expands.

2. The battery pack according to claim 1, wherein, The aforementioned outer casing material has a receiving portion and a peripheral sealing portion. The receiving portion houses the energy storage unit and the electrolyte together, and the peripheral sealing portion seals the receiving portion by surrounding it. The aforementioned protrusion is positioned opposite the peripheral sealing portion of the aforementioned outer material.

3. The battery pack according to claim 2, wherein, The aforementioned protrusions are provided on the aforementioned intermediate plate and at least two locations of the aforementioned receiving portion separated by the aforementioned outer material.

4. The battery pack according to claim 2, wherein, The intermediate plate is provided with a spacing retaining part, which maintains the distance between the peripheral sealing parts of the two pouch battery cells and the intermediate plate sandwiched between them.

5. The battery pack according to claim 4, wherein, The aforementioned spacing retaining portion is located at a position further away from the aforementioned receiving portion than the aforementioned protrusion.

6. The battery pack according to claim 1, wherein, The aforementioned protrusions are provided on both sides of the aforementioned intermediate plate.

7. The battery pack according to claim 6, wherein, It has at least four of the above-mentioned pouch-type battery cells arranged in a specified orientation. When N (N is a natural number) is used to represent the arrangement order of each of the above-mentioned pouch-type battery cells in the above-mentioned arrangement direction, the above-mentioned intermediate plate is arranged between the 2Nth and 2N-1th pouch-type battery cells, and the above-mentioned intermediate plate is not arranged between the 2Nth and 2N+1th pouch-type battery cells.

8. The battery pack according to claim 7, wherein, The intermediate plate is fixed to at least one of the 2Nth pouch cell and the 2N-1th pouch cell in the above arrangement direction.

9. A battery module, wherein, have: The battery pack according to any one of claims 1 to 8; and The outer casing houses the aforementioned battery pack.

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