Power storage device

Abstract

To achieve both ease of assembly of a storage module to a storage case and difficulty in removing the storage module from the storage case when an external force is applied. The power storage device includes a power storage module including a plurality of power storage cells and a module case that houses the plurality of power storage cells, and a power storage case that houses the power storage module. Accumulate A first guide groove is formed in one of a first inner surface of the battery case and a first outer surface of the module case facing the first inner surface, and extends along a first direction. A first protrusion that engages with the first guide groove is formed in the other of the first inner surface and the first outer surface. A second guide groove is formed in one of a second inner surface of the battery case facing the first inner surface and a second outer surface of the module case facing the second inner surface, and extends along the first direction. A second protrusion that engages with the second guide groove is formed in the other of the second inner surface and the second outer surface.

Description

[Technical Field]

[0001] The present disclosure relates to a power storage device, and more particularly to a power storage device included in a mobile object. [Background technology]

[0002] Patent Document 1 discloses an electric storage device mounted on a vehicle. The electric storage device includes a plurality of electric storage modules and a housing case that houses the plurality of electric storage modules. The housing case includes an upper case and a lower case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-155367 Summary of the Invention [Problem to be solved by the invention]

[0004] The energy storage device is required to have a structure that allows the energy storage module to be easily assembled into the energy storage case that houses the energy storage module, and also to have a structure that makes it difficult for the energy storage module to come off the energy storage case when an external force acts on the energy storage case. [Means for solving the problem]

[0005] The energy storage device according to the present disclosure includes an energy storage module and an energy storage case. The energy storage module includes a plurality of energy storage cells and a module case that houses the plurality of energy storage cells. The energy storage case houses the energy storage module. A first guide groove is formed in one of a first inner surface of the energy storage case and a first outer surface of the module case that faces the first inner surface, and extends along a first direction. A first protrusion that engages with the first guide groove is formed in the other of the first inner surface and the first outer surface. A second guide groove is formed in one of a second inner surface of the energy storage case that faces the first inner surface, and a second outer surface of the module case that faces the second inner surface, and extends along the first direction. A second protrusion that engages with the second guide groove is formed in the other of the second inner surface and the second outer surface. [Effects of the Invention]

[0006] According to the energy storage device disclosed herein, when the energy storage module is inserted into the energy storage case with the first and second protrusions aligned with the first and second guide grooves, respectively, the energy storage module slides in the first direction while being guided by the first and second guide grooves, respectively, and moves to a predetermined assembly position. In this way, a structure is obtained that facilitates assembly of the energy storage module into the energy storage case. Inside the energy storage case, the first guide groove and the first protrusion engage with each other on the first inner surface side, and the second guide groove and the second protrusion engage with each other on the second inner surface side opposite the first inner surface. This results in a structure that makes it difficult for the energy storage module to come off the energy storage case when an external force acts on the energy storage case. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is an exploded perspective view of the electricity storage device according to the embodiment. [Figure 2] 4A to 4C are diagrams showing first and second shape examples relating to first and second guide grooves and first and second protrusions. [Figure 3] 3A and 3B are cross-sectional views showing the configuration of the electricity storage device before and after the electricity storage module is assembled. [Figure 4]FIG. 2 is an exploded perspective view of the electricity storage module. [Figure 5] This is a view of two energy storage modules viewed from above. [Figure 6] FIG. 2 is a perspective view of an electricity storage case in which components such as an electricity storage module are assembled. [Figure 7] 10 is a cross-sectional view showing another example of the structure of a case body in which a guide groove that engages with a protrusion having a cooling passage is formed. FIG. [Figure 8] FIG. 10 is a schematic diagram showing a cross section of an electricity storage case according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Embodiments of the present disclosure will be described with reference to the accompanying drawings. Elements common to the drawings will be designated by the same reference numerals, and redundant explanations will be omitted or simplified.

[0009] 1. Configuration of the energy storage device 1 is an exploded perspective view of a power storage device 1 according to this embodiment. The power storage device 1 is included in, for example, a moving object, and supplies the moving object with electric power for moving the moving object. The moving object here is, for example, a vehicle (e.g., an electrically powered vehicle such as a battery electric vehicle (BEV)) or a robot.

[0010] 1-1. Energy storage module and energy storage case The power storage device 1 includes a power storage module 10 and a power storage case 20. The power storage case 20 houses the power storage module 10. The power storage device 1 is included in (in other words, mounted on) a mobile object, for example, as a power storage pack. In this example, the power storage case 20 corresponds to a case (pack case) of the power storage pack. Alternatively, in another example of the power storage device 1 included in a mobile object, the power storage case 20 may be a component part of the mobile object (for example, a body part of a vehicle).

[0011] In the example shown in FIG. 1, the energy storage device 1 includes two energy storage modules 10. However, the number of energy storage modules included in the "energy storage device" according to the present disclosure may be one, or three or more. The energy storage module 10 includes a plurality of energy storage cells 11 (see FIG. 2(A)) and a module case 12. The module case 12 houses the plurality of energy storage cells 11. The energy storage cells 11 are, for example, battery cells, but may also be capacitor cells.

[0012] The energy storage case 20 includes a case body 21 and a case lid 22. The case body 21 has, for example, a rectangular parallelepiped shape, but may also have a cubic shape. One longitudinal end of the case body 21 is open as an opening 23. Components of the energy storage device 1, such as the energy storage module 10, are inserted (i.e., assembled) into the case body 21 along an insertion direction D1 (first direction) parallel to the longitudinal direction. The case lid 22 is used to close the opening 23 after the components are housed in the case body 21. The case lid 22 is attached to the case body 21 by, for example, bolts 24. Fastening holes 25 for the bolts 24 are formed in the case body 21. The other longitudinal end of the case body 21 is closed by a cover 26 (see FIG. 3 ) that is fixed to the case body 21 by, for example, fastening or welding. Alternatively, the case body 21 and the cover 26 may be integrally formed.

[0013] 1-2. Guide groove and protrusion 2(A), 2(B), and 3 are referenced in addition to FIG. 1. Each of FIGS. 2(A) and 2(B) is a cross-sectional view of the energy storage module 10 inserted into the energy storage case 20, as viewed from the insertion direction D1. FIG. 3 is a cross-sectional view showing the configuration of the energy storage device 1 before and after the energy storage module 10 is assembled. The position of the cross section shown in FIG. 3 is indicated by line AA in FIG. 2(A). Note that FIG. 2(B) shows a second example of the shapes of the "first and second guide grooves" and the "first and second protrusions," as will be described later.

[0014] The module case 12 has, for example, a generally rectangular parallelepiped or cubic shape. The module case 12 is formed using a metal material such as iron or aluminum. As shown in FIG. 2(A), the module case 12 includes an upper wall 12U located above the energy storage cells 11 in the vertical direction D2 and a lower wall 12L located below the energy storage cells 11 in the vertical direction D2. Similarly, the case body 21 includes an upper wall 21U and a lower wall 21L. The case body 21 is formed using a metal material such as iron or aluminum. The case body 21 may be manufactured using, for example, an extruded material, or may be manufactured by welding a plurality of sheet metal members. In addition, the thickness of the case body 21 is, for example, 10 to 30 mm, which is larger than the thickness of a typical energy storage case having a lower case and an upper case for accommodating an energy storage module (e.g., Patent Document 1).

[0015] A guide groove 27U (first guide groove) is provided on the inner surface 21UI (first inner surface) of the top wall 21U of the case body 21. As shown in FIGS. 1 and 3, the guide groove 27U is formed to extend along the insertion direction D1. A guide groove 27L (second guide groove) is provided on the inner surface 21LI (second inner surface) of the bottom wall 21L opposite the inner surface 21UI. Like the guide groove 27U, the guide groove 27L is formed to extend along the insertion direction D1. As an example, the formation range of each of the guide grooves 27U and 27L extends over the entire case body 21 in the insertion direction D1 (i.e., from one end of the opening 23 (one end) of the case body 21 to the other end) (see FIG. 3).

[0016] On the other hand, a protrusion 13U (first protrusion) is provided on an outer surface 12UO (first outer surface) of the upper wall 12U of the module case 12. The outer surface 12UO faces the inner surface 21UI. The protrusion 13U protrudes vertically upward from the outer surface 12UO and is formed to engage with the guide groove 27U inside the guide groove 27U. A protrusion 13L (second protrusion) is provided on an outer surface 12LO (second outer surface) of the lower wall 12L. The outer surface 12LO faces the inner surface 21LI. Like the protrusion 13U, the protrusion 13L protrudes vertically downward from the outer surface 12LO and is formed to engage with the guide groove 27L inside the guide groove 27L. Each of the protrusions 13U and 13L is formed to extend along the insertion direction D1. As an example, the range in which the protrusions 13U and 13L are formed covers the entire module case 12 in the insertion direction D1 (see FIG. 1).

[0017] (First shape example) 2(A), guide groove 27U has a tapered cross-sectional shape that becomes thicker vertically upward when viewed from insertion direction D1 (in other words, a cross-sectional shape of an inverted triangle with its base positioned vertically upward). Protrusion 13U has a tapered cross-sectional shape similar to that of guide groove 27U and engages with guide groove 27U. More specifically, protrusion 13U has a tapered cross-sectional shape that is slightly smaller than the tapered cross-sectional shape of guide groove 27U.

[0018] Similarly, the guide groove 27L has a tapered cross-sectional shape that becomes thicker vertically downward when viewed from the insertion direction D1 (in other words, a triangular cross-sectional shape with its base positioned vertically downward). The protrusion 13L has a tapered cross-sectional shape similar to that of the guide groove 27L and engages with the guide groove 27L. More specifically, the protrusion 13L has a tapered cross-sectional shape that is slightly smaller than the tapered cross-sectional shape of the guide groove 27L. In addition, the guide grooves 27U and 27L having the cross-sectional shape according to the first shape example can also be considered an example of a dovetail-shaped guide groove.

[0019] A direction perpendicular to each of the vertical direction D2 and the insertion direction D1 is referred to herein as the "left-right direction D3." Due to the tapered cross-sectional shape described above, the protrusion 13U engages with the guide groove 27U so as to restrict movement of the module case 12 relative to the electricity storage case 20 in each of the vertical direction D2 and the left-right direction D3. Similarly, the protrusion 13L engages with the guide groove 27L so as to restrict movement of the module case 12 relative to the electricity storage case 20 in each of the vertical direction D2 and the left-right direction D3.

[0020] (Second shape example) In the second shape example shown in FIG. 2(B), the case main body 21 includes guide grooves 28U and 28L instead of the guide grooves 27U and 27L, and the module case 12 includes protrusions 14U and 14L instead of the protrusions 13U and 13L. When viewed from the insertion direction D1, the guide groove 28U has a cross-sectional shape that is narrow in the left-right direction D3 on the lower side in the vertical direction D2 and widens in the left-right direction D3 on the upper side in the vertical direction D2 (in other words, a T-shaped cross-sectional shape). The protrusion 14U has a cross-sectional shape similar to that of the guide groove 28U and is engaged with the guide groove 28U. More specifically, the protrusion 14U has a cross-sectional shape that is slightly smaller than the cross-sectional shape of the guide groove 28U.

[0021] Like the guide groove 28U, the guide groove 28L has a cross-sectional shape (in other words, an inverted T-shaped cross-sectional shape) that narrows in the left-right direction D3 above the vertical direction D2 when viewed from the insertion direction D1 and widens in the left-right direction D3 below the vertical direction D2. The protrusion 14L has a cross-sectional shape similar to that of the guide groove 28L and engages with the guide groove 28L. More specifically, the protrusion 14L has a cross-sectional shape that is slightly smaller than the cross-sectional shape of the guide groove 28L. In addition, the guide grooves 28U and 28L having the cross-sectional shape according to the second shape example can also be considered another example of a dovetail-shaped guide groove.

[0022] Due to the above-described cross-sectional shape, the protrusion 14U engages with the guide groove 28U so as to restrict movement of the module case 12 relative to the electricity storage case 20 in both the vertical direction D2 and the left-right direction D3. Similarly, the protrusion 14L engages with the guide groove 28L so as to restrict movement of the module case 12 relative to the electricity storage case 20 in both the vertical direction D2 and the left-right direction D3.

[0023] (Smoke exhaust passage) As shown in FIG. 2(A), a smoke exhaust passage 29 may be formed inside the protrusion 13U of the module case 12. In the example described here, each storage cell 11 is a battery cell having a smoke exhaust valve (safety valve) 15. The smoke exhaust valve 15 is configured to open in response to an increase in internal pressure of the storage cell 11. As an example, each storage cell 11 is arranged in the module case 12 so that the smoke exhaust valve 15 faces upward in the vertical direction D2. In addition, as an example, the smoke exhaust valve 15 is arranged between a pair of electrode terminals 16 on the upper surface of the storage cell 11.

[0024] A "smoke exhaust path" may be provided inside the electricity storage case 20 to guide gas (smoke) ejected from the smoke exhaust valve 15 of each electricity storage cell 11 to the outside of the electricity storage case 20. The smoke exhaust passage 29 functions as the smoke exhaust path together with the guide groove 27U and the passage 31 (see FIG. 3). The passage 31 is formed to penetrate the case lid 22 in the insertion direction D1 at a position corresponding to the guide groove 27U.

[0025] The smoke exhaust passage 29 communicates with the interior of the module case 12. More specifically, as an example, the smoke exhaust passage 29 is formed to have a guide portion 29G that protrudes downward from the module case 12 in the vertical direction D2. As shown in FIG. 2(A) , the smoke exhaust valve 15 of each energy storage cell 11 is disposed directly below a lower end 29L of the smoke exhaust passage 29 in the vertical direction D2.

[0026] 1 and 3, the smoke exhaust passage 29 is formed to extend along the insertion direction D1. Side ends 29S1 and 29S2 of the smoke exhaust passage 29 in the insertion direction D1 are open and communicate with the guide groove 27U. The upper end 29U of the smoke exhaust passage 29 may be open and communicate with the guide groove 27U as shown in FIG. 2(A), or may be closed.

[0027] According to the smoke exhaust passage 29 formed as described above, smoke exhausted from a certain energy storage cell 11 can be guided to the outside of the module case 12 by using the protrusion 13U. More specifically, the end of the guide groove 27U on the cover 26 side is closed by the cover 26. Therefore, as shown in FIG. 3 , smoke exhausted from any energy storage cell 11 in the energy storage module 10 can be guided to the outlet of the smoke exhaust path (the outer end 31E of the passage 31) via the smoke exhaust passage 29, the guide groove 27U, and the passage 31. Additionally, in an example in which the smoke exhaust passage 29 has the guide portion 29G described above, the guide portion 29G can be used to more effectively guide the smoke into the smoke exhaust passage 29. A relief valve 32 is provided at the outlet. The relief valve 32 is configured to open when the smoke exhaust is subjected to high pressure.

[0028] In the second shape example, as shown in FIG. 2(B), a smoke exhaust passage 30 similar to the smoke exhaust passage 29 may be formed inside the protrusion 14U.

[0029] (cooling passage) As shown in FIG. 2(A), a cooling passage 33 may be formed inside the protrusion 13L of the module case 12. A "cooling path" for flowing a refrigerant for cooling the multiple energy storage cells 11 of each energy storage module 10 may be provided inside the energy storage case 20. The cooling passage 33 located inside the guide groove 27L functions as the cooling path together with passages 35 and 36. The passage 35 is formed to penetrate the case lid 22 in the insertion direction D1 at a position corresponding to the guide groove 27L. Similarly, the passage 36 is formed to penetrate the cover 26 in the insertion direction D1 at a position corresponding to the guide groove 27L.

[0030] The cooling passage 33 is closed above the protrusion 13L in the vertical direction D2. That is, the cooling passage 33 is formed so as not to communicate with the interior of the module case 12. As shown in Fig. 3, the cooling passage 33 is formed so as to extend along the insertion direction D1. Each of side ends 33S1 and 33S2 of the cooling passage 33 in the insertion direction D1 is open and communicates with the guide groove 27L.

[0031] The refrigerant flowing through the cooling passage 33 is, for example, air (outside air). In the example of the protrusion 13L shown in Fig. 2(A), the cooling passage 33 is formed using a fin shape that protrudes downward from the protrusion 13L in the vertical direction D2. In addition, although the cooling passage 33 is open at the lower end of the protrusion 13L, it may also be a closed passage inside the protrusion 13L.

[0032] A fan 37 is provided in the passage 35 formed in the case lid 22. For example, when cooling of the energy storage module 10 is required, the fan 37 operates in accordance with instructions from an ECU 51 (described later) and circulates cooling air (refrigerant) through a cooling path including the cooling passage 33. This makes it possible to cool the multiple energy storage cells 11 via the module case 12. More specifically, in the example of the energy storage cells 11 arranged as shown in FIG. 2(A), the cooling air directly cools the bottom wall 12L of the module case 12 that is in contact with each energy storage cell 11, thereby making it possible to effectively cool each energy storage cell 11.

[0033] Additionally, power for operating the fan 37 may be supplied from the power storage module 10. The fan 37 may be configured to push air into the cooling path, or may be configured to suck air out of the cooling path. The fan 37 may be provided in the passage 36 instead of the passage 35. The refrigerant flowing through the cooling path including the cooling passage 33 may be a liquid refrigerant such as cooling water.

[0034] In the second shape example as well, as shown in FIG. 2(B), a cooling passage 34 similar to the cooling passage 33 may be formed inside the protrusion 14L.

[0035] 1-3. Further explanation of each part structure Please refer to Figures 4 and 5 in addition to Figures 1, 2(A), 2(B), and 3. Figure 4 is an exploded perspective view of the energy storage module 10. Figure 5 is a view of the two energy storage modules 10 viewed from above.

[0036] As shown in Fig. 4, the module case 12 may be a combination of an upper case 12UPR and a lower case 12LWR that are divided into two halves, for example, an upper case 12UPR and an upper case 12LWR, in the vertical direction D2. The upper case 12UPR integrally includes an upper wall 12U including a protrusion 13U (or 14U) and the upper halves of two side walls 12S1 and 12S2. The lower case 12LWR integrally includes a lower wall 12L including a protrusion 13L (or 14L) and the lower halves of two side walls 12S1 and 12S2. In Fig. 4, the two side walls 12S3 and 12S4 (see Fig. 2(A)) of the module case 12 in the left-right direction D3 are not shown in order to show the internal structure of the energy storage module 10. For example, the upper half of each of the side walls 12S3 and 12S4 may be integrally formed with the upper case 12UPR, and similarly, the lower half of each of the side walls 12S3 and 12S4 may be integrally formed with the lower case 12LWR. Note that the module case 12 may be formed in any divided form other than that described above.

[0037] 4, the plurality of energy storage cells 11 are battery cells stacked in the same direction as the insertion direction D1. The plurality of energy storage cells 11 in one energy storage module 10 are constrained, for example, as follows: In a state in which a compressive load is applied to the plurality of energy storage cells 11 from both sides in the above-mentioned direction by the pair of end plates 38, the plurality of energy storage cells 11 are housed in the lower case 12LWR together with the pair of end plates 38. Then, the upper case 12UPR and the lower case 12LWR (two side walls 12S3 and 12S4) are fixed to the end plates 38 by a method such as welding.

[0038] As shown in Fig. 4, a busbar module 39 is disposed above each energy storage cell 11 in the module case 12. The busbar module 39 includes a plurality of inter-cell busbars for electrically connecting the electrode terminals 16 of each energy storage cell 11 in series or parallel. Since one of the purposes of Fig. 4 is to show the arrangement of the busbar module 39 for each energy storage cell 11 in the module case 12, the busbar module 39 is simply represented by a single plate. In addition, the busbar module 39 is formed so as to ensure a space between the smoke vent 15 of each energy storage cell 11 and the protrusion 13U.

[0039] 1 and 5, the energy storage device 1 further includes inter-module bus bars 40 arranged outside each module case 12. Two inter-module bus bars 40 are provided, for example, as inter-module bus bars 40-1 and 40-2. For ease of explanation, the energy storage module 10 located on the rear side in the insertion direction D1 will be referred to as energy storage module 10-1, and the energy storage module 10 located on the front side in the insertion direction D1 will be referred to as energy storage module 10-2. Each of the bus bars 40-1 and 40-2 is attached to each module case 12 via an insulating material (not shown) so as to connect two adjacent energy storage modules 10-1 and 10-2. In addition, the inter-module bus bars 40 are provided, for example, in the center of each module case 12 in the vertical direction D2.

[0040] More specifically, the bus bar 40-1 has two fastening holes 40H1 and 40H2. As shown in FIG. 5 , a conductive member 41 extends from the interior of the module case 12 of the energy storage module 10-1 to the exterior through a hole (not shown) formed in the module case 12. The conductive member 41 and conductive members 43-46 described below are each, for example, a bus bar or a cable. In an example of a series connection in which the energy storage cells 11 included in the two energy storage modules 10-1 and 10-2 are connected in series, one end of the conductive member 41 is connected to the negative electrode terminal 16 that is lowest in potential among the energy storage cells 11 included in the energy storage module 10-1. The bus bar 40-1, together with the other end of the conductive member 41, is fastened to the side wall 12S3 of the energy storage module 10-1 by a bolt 42 via the fastening hole 40H1. Furthermore, the bus bar 40-1 is fastened to the side wall 12S3 of the energy storage module 10-2 by a bolt 42 via the fastening hole 40H2, together with one end of the conductive member 43. In the example of series connection, the other end of the conductive member 43 is connected to the positive electrode terminal 16 of the energy storage cell 11 included in the energy storage module 10-2 that is highest in terms of potential. With this configuration, the adjacent energy storage modules 10-1 and 10-2 are mechanically coupled together by using the bus bar 40-1 that electrically connects the conductive member 41 of one energy storage module 10-1 to the conductive member 43 of the other energy storage module 10-2.

[0041] Similarly, the bus bar 40-2 has two fastening holes 40H3 and 40H4. The bus bar 40-2, together with one end of the conductive member 44, is fastened to the side wall 12S4 of the energy storage module 10-2 by a bolt 42 via the fastening hole 40H3. In the example of the series connection, the other end of the conductive member 44 is connected to the negative electrode terminal 16, which is the lowest in terms of potential, of the energy storage cells 11 included in the energy storage module 10-2. The bus bar 40-2, together with one end of the conductive member 45, is fastened to the side wall 12S4 of the energy storage module 10-1 by a bolt 42 via the fastening hole 40H4. In the example of the series connection, the other end of the conductive member 45, together with one end of the conductive member 46, is connected to a junction box (J / B) 47. The other end of the conductive member 46 is connected to the positive electrode terminal 16, which is the highest in terms of potential, of the energy storage cells 11 included in the energy storage module 10-1. According to this configuration, adjacent energy storage modules 10-1 and 10-2 are mechanically coupled using bus bar 40-2 that is interposed in the conductive path for guiding conductive member 44 from energy storage module 10-2 to J / B 47.

[0042] In the example shown in FIG. 5 , the inter-module bus bar 40-1 has a hat structure. That is, the bus bar 40-1 is formed with a pair of fastening portions P1 and P2 in which fastening holes 40H1 and 40H2 are formed, a pair of upright portions P3 and P4 that stand in a direction away from the pair of fastening portions P1 and P2, and an intermediate portion P5 that connects the pair of upright portions P3 and P4. This makes it possible to more effectively absorb vibrations acting on the two energy storage modules 10 along the insertion direction D1, compared to an example in which the inter-module bus bar is formed of a simple flat plate. The same applies to the bus bar 40-2. In addition, by providing both bus bars 40-1 and 40-2, it is possible to connect multiple energy storage modules 10 while reducing the force acting on a single bus bar 40 when assembling or removing the multiple energy storage modules 10 from the energy storage case 20. However, the plurality of power storage modules 10 may be connected using only one of the bus bars 40-1 and 40-2.

[0043] 1 and 3, an elastic member 48 may be disposed between two adjacent energy storage modules 10 to fill the gap between the two energy storage modules 10. The elastic member 48 is, for example, a rubber member, and more specifically, is desirably made of soft rubber to improve adhesion. To improve assembly, the elastic member 48 may be attached to the module case 12 of one of the two adjacent energy storage modules 10 using, for example, double-sided tape. Similarly, to fill the gap, the elastic member 48 may be disposed between the cover 26 (see FIG. 3) and the opposing energy storage module 10, or between a restraining plate 49 and the opposing energy storage module 10.

[0044] 1 and 3, a restraint plate 49 is provided to press and fix the energy storage module 10 inserted into the energy storage case 20 against the energy storage case 20. That is, the insertion direction D1 of the energy storage module 10 corresponds to the direction in which the energy storage module 10 is pressed against the energy storage case 20. The restraint plate 49 is attached to the energy storage case 20 by, for example, a bolt 50. Fastening holes (not shown) for the bolts 50 are formed in the inner wall of the energy storage case 20 (e.g., the cover 26). By using the restraint plate 49, the module case 12 of each energy storage module 10 is fixed to the energy storage case 20 so that movement of the module case 12 in the insertion direction D1 relative to the energy storage case 20 is restrained.

[0045] The restraint plate 49 is formed using, for example, a metal material such as iron. The restraint plate 49 has, for example, a hollow box shape, and electrical devices (including electronic devices) such as a J / B 47 and an electronic control unit (ECU) 51 may be housed inside the restraint plate 49. The J / B 47 has, for example, electrical components such as relays and fuses, as well as connectors connected to the electrical components. The ECU 51 executes processes related to management of the energy storage device 1 (for example, monitoring the voltage and temperature of each energy storage cell 11 and controlling the temperature). The case lid 22 may be formed to also serve as the restraint plate 49.

[0046] 1-4. Assembly of the energy storage device When assembling the energy storage module 10 into the energy storage case 20, one side of the energy storage case 20 is opened as an opening 23, as shown in Fig. 3. The energy storage module 10 is inserted into the energy storage case 20 (case main body 21) using the opening 23. More specifically, the energy storage module 10 is inserted into the case main body 21 with the positions of the protrusions 13U and 13L of the energy storage module 10 aligned with the positions of the guide grooves 27U and 27L, respectively. Inside the case main body 21, the energy storage module 10 slides along the insertion direction D1 while the protrusions 13U and 13L are guided by the guide grooves 27U and 27L, respectively, and moves to a predetermined assembly position.

[0047] Components of the energy storage device 1, such as the energy storage modules 10, the inter-module bus bars 40, the elastic members 48, and the restraint plates 49, may be inserted and assembled into the energy storage case 20 in order from the one located at the front in the insertion direction D1. Alternatively, the components may be assembled into the energy storage case 20 as follows, for example, before being assembled into the energy storage case 20. That is, first, an elastic member 48 may be interposed between two energy storage modules 10, and the two energy storage modules 10 may then be connected by an inter-module bus bar 40 (e.g., 40-1 and 40-2). Next, the remaining elastic members 48 may be attached to each energy storage module 10. The assembly thus obtained, including the energy storage modules 10, the bus bars 40, and the elastic members 48, may be inserted into the energy storage case 20 so as to slide until it abuts against a wall (i.e., the cover 26) within the energy storage case 20. Then, a restraint plate 49 may be fastened with a bolt 50 to restrain the assembly. After the restraint plate 49 is attached, the case lid 22 is fixed to the case body 21 by the bolts 24 .

[0048] 1 , in an example in which a plurality of energy storage modules 10 are assembled, the assembling of the energy storage device 1 can be favorably improved by connecting the plurality of energy storage modules 10 in advance using the inter-module bus bars 40 as described above. Furthermore, connecting the plurality of energy storage modules 10 using the inter-module bus bars 40 also improves the workability when removing the plurality of energy storage modules 10 from the energy storage case 20.

[0049] 1-5. Shape of the outer surface of the battery case FIG. 6 is a perspective view of the energy storage case 20 to which components such as the energy storage module 10 are assembled. As described above, the case body 21 has a rectangular parallelepiped (or cubic) shape. Guide grooves 27U and 27L are formed on the inner surface 21UI (first inner surface) of the upper wall 21U of the case body 21 and the inner surface 21LI (second inner surface) of the lower wall 21L, respectively. In contrast, as shown in FIG. 6, each of the outer surfaces 21UO, 21LO, 21S1, and 21S2 of the case body 21 is flat. Broadly speaking, the energy storage case 20 including the case lid 22 and the cover 26 together with the case body 21 also has a rectangular parallelepiped (or cubic) shape, and each of the outer surfaces of the energy storage case 20 is also flat.

[0050] 1-6.Other structural examples of guide grooves and protrusions Unlike the example shown in FIG. 2(A), two or more guide grooves 27U (first guide grooves) may be formed on the inner surface 21UI (first inner surface) of the electricity storage case 20 (case main body 21). Correspondingly, two or more protrusions 13U (first protrusions) may be formed on the outer surface 12UO (first outer surface) of the module case 12. The same applies to the pair of guide groove 27L (second guide groove) and protrusion 13L (second protrusion). The same applies to the example shown in FIG. 2(B).

[0051] 2(A) and 2(B), the "first outer surface" on which the "first protrusion" is formed may be the outer surface of one of the side walls 12S3 and 12S4 of the module case 12, and the "first inner surface" on which the "first guide groove" is formed may be the inner surface of the side wall of the energy storage case 20 facing the one of the side walls 12S3 and 12S4. The "second outer surface" on which the "second protrusion" is formed may be the outer surface of the other of the side walls 12S3 and 12S4, and the "second inner surface" on which the "second guide groove" is formed may be the inner surface of the side wall of the energy storage case 20 facing the other of the side walls 12S3 and 12S4.

[0052] 2(A) and 2(B), the "first guide groove" may be formed on the outer surface 12UO (first outer surface) of the module case 12, and the "first protrusion" may be formed on the inner surface 21UI (first inner surface) of the power storage case 20. Similarly, the "second guide groove" may be formed on the outer surface 12LO (second outer surface) of the module case 12, and the "second protrusion" may be formed on the inner surface 21LI (second inner surface) of the power storage case 20.

[0053] Next, FIG. 7 is a cross-sectional view showing another example of the structure of the case body 21 in which a guide groove 27L is formed to engage with a protrusion 13L having a cooling passage 33. In the example shown in FIG. 7, the bottom wall 21L of the case body 21 additionally includes the following structure. That is, the bottom wall 21L of this example is formed with a pair of flow paths 52 for injecting thermally conductive resin from the outside. The pair of flow paths 52 extend along the insertion direction D1, similar to the guide groove 27L. The thermally conductive resin has high thermal conductivity and is used to fill a pair of gaps G between the guide groove 27L and the protrusion 13L, which face each other in the left-right direction D3. The thermally conductive resin is injected into the pair of gaps G from each of the pair of flow paths 52 via flow paths 53 when the energy storage module 10 is assembled to the case body 21 as shown in FIG. 7. The thermally conductive resin then hardens to form a pair of thermally conductive resin layers 54. The pair of thermally conductive resin layers 54 improves thermal conduction between the module case 12 and the energy storage case 20 (heat dissipation to the energy storage case 20), thereby improving the cooling performance of the energy storage cells 11 using the cooling passages 33. Furthermore, the pair of thermally conductive resin layers 54 can prevent moisture contained in the cooling air from penetrating into the energy storage case 20 through the gaps (including the pair of gaps G) between the module case 12 and the energy storage case 20 from the cooling passages 33. The configuration shown in FIG. 7 may be similarly applied to the second shape example shown in FIG. 2(B).

[0054] 2.Effects According to the energy storage device 1 of this embodiment, when the energy storage module 10 is assembled into the energy storage case 20, the protrusions 13U and 13L are guided by the guide grooves 27U and 27L, respectively, as described above, while the energy storage module 10 slides along the insertion direction D1, and moves to a predetermined assembly position. In this way, a structure is obtained that facilitates assembly of the energy storage module 10 into the energy storage case 20. That is, the assembly of the energy storage device 1 is improved. On the other hand, when the energy storage module 10 is pressed against and fixed to the energy storage case 20 as described above, it is also required that the energy storage module 10 is not easily removed in directions other than the pressing direction (i.e., the insertion direction D1). In this regard, inside the electricity storage case 20, the guide groove 27U and the protrusion 13U engage with each other on the side of the inner surface 21UI (first inner surface) of the upper wall 21U, and the guide groove 27L and the protrusion 13L engage with each other on the side of the inner surface 21LI (second inner surface) of the lower wall 21L opposite the inner surface 21UI. This provides a structure in which the electricity storage module 10 is unlikely to come off from the electricity storage case 20 even if an external force acts on the electricity storage case 20 from a direction other than the above-mentioned pressing direction.

[0055] Furthermore, the first protrusions (e.g., 13U, 14U) are engaged with the first guide grooves (e.g., 27U, 28U) so as to restrict movement of the module case 12 relative to the energy storage case 20 in the vertical direction D2 and the left-right direction D3. The same applies to the relationship between the second protrusions and the second guide grooves. This provides a structure in which the energy storage module 10 is less likely to come off the energy storage case 20 in the vertical direction D2 or the left-right direction D3 when an external force acts on the energy storage case 20.

[0056] Furthermore, smoke exhaust passages (e.g., 29, 30) are formed inside the first protrusions (e.g., 13U, 14U) formed on the outer surface 12UO of the module case 12. This allows smoke to be exhausted using the first protrusions and first guide grooves provided to improve the ease of assembly and resistance to removal of the energy storage module 10. This contributes to space-saving of the energy storage case 20 compared to an example in which a component for forming a smoke exhaust passage is added separately from the first protrusions. Furthermore, the smoke exhaust passages enable more efficient smoke exhaust in an example in which the energy storage cells 11 are arranged in the module case 12 so that the smoke exhaust valves 15 face upward in the vertical direction D2 (see FIGS. 2(A) and 2(B)).

[0057] Furthermore, cooling passages (e.g., 33, 34) are formed inside second protrusions (e.g., 13L, 14L) formed on the outer surface 12LO of the module case 12. This allows the energy storage cells 11 to be cooled by utilizing the second protrusions and second guide grooves provided to improve the ease of assembly and removal of the energy storage module 10. This contributes to space-saving of the energy storage device 1 compared to an example in which a component for forming the cooling passages is added separately from the second protrusions. Furthermore, the cooling passages can directly cool the module case 12 that houses the energy storage cells 11, thereby allowing the energy storage cells 11 to be cooled more effectively than an example in which cooling passages are provided to cool the energy storage case 20. Furthermore, the cooling passages are formed so as not to communicate with the interior of the module case 12. This allows the energy storage cells 11 to be cooled while preventing water from entering the interior of the module case 12 via the cooling passages.

[0058] FIG. 8 is a schematic diagram showing a cross section of an electricity storage case according to a comparative example. A typical electricity storage case (pack case) having a case body (lower case) and a case lid (upper case) for accommodating an electricity storage module may be provided with a flange portion for covering an opening of the case body parallel to the horizontal direction with the case lid. To accommodate a waterproof sealant, the flange portion may be formed to protrude horizontally from each of the lower case and the upper case, as shown in FIG. 8 . This may restrict the installation of the electricity storage pack in various mobile objects. In contrast, as described above, at least the outer surfaces 21UO, 21LO, 21S1, and 21S2 of the case body 21 of the electricity storage case 20 are flat. This contributes to improving the installability of the electricity storage device 1 in various mobile objects when the electricity storage device 1 is configured as an electricity storage pack.

[0059] In addition, in the energy storage case 20, the opening 23 for inserting and removing the energy storage module 10 is formed on only one side surface of the case body 21, as shown in Fig. 1. This makes it possible to reduce the contact surface between the case body and the case lid, compared to when the energy storage case 20 is formed so as to have a case body and a case lid that are divided into upper and lower halves in the vertical direction D2, as in the comparative example shown in Fig. 8. This also leads to space-saving for the energy storage case 20.

[0060] Furthermore, in the energy storage device 1, the protrusions 13U engage with the guide grooves 27U on the side of the upper wall 21U of the case main body 21, and the protrusions 13L engage with the guide grooves 27L on the side of the lower wall 21L. As a result, for the energy storage case 20, the module case 12 functions as a beam extending along the insertion direction D1 on each side of the upper wall 21U and the lower wall 21L. Therefore, compared to an example in which a reinforcing member for the energy storage case 20 is separately provided, it is possible to reinforce the energy storage case 20 while saving space. Furthermore, the module case 12 functioning as a beam as described above can improve protection of the energy storage cells 11 against external forces acting on the energy storage case 20 from above or below in the vertical direction D2. [Explanation of symbols]

[0061] REFERENCE SIGNS LIST 1 Energy storage device, 10 Energy storage module, 11 Energy storage cell, 12 Module case, 13L, 13U, 14L, 14U Protrusion, 20 Energy storage case, 27L, 27U, 28L, 28U Guide groove, 29, 30 Smoke exhaust passage, 33, 34 Cooling passage

Claims

1. an electricity storage module including a plurality of electricity storage cells and a module case that houses the plurality of electricity storage cells; a storage case that houses the storage module; Equipped with a first guide groove is formed in one of a first inner surface of the storage case and a first outer surface of the module case facing the first inner surface, the first guide groove extending along a first direction; a first protrusion that engages with the first guide groove is formed on the other of the first inner surface and the first outer surface; a second guide groove is formed in one of a second inner surface of the storage case facing the first inner surface and a second outer surface of the module case facing the second inner surface, the second guide groove extending along the first direction; The other of the second inner surface and the second outer surface is formed with a second protrusion that engages with the second guide groove. Energy storage device.

2. The power storage device according to claim 1, the first inner surface and the first outer surface are located above the plurality of energy storage cells in a vertical direction, the second inner surface and the second outer surface are located below the plurality of energy storage cells in the vertical direction, A direction perpendicular to each of the vertical direction and the first direction is referred to as a left-right direction, the first protrusion engages with the first guide groove so as to restrict movement of the module case relative to the storage case in each of the vertical direction and the left-right direction; The second protrusion is engaged with the second guide groove so that movement of the module case relative to the storage case is restricted in both the vertical direction and the left-right direction. Energy storage device.

3. The power storage device according to claim 2, the first protrusion is formed on the first outer surface, A smoke exhaust passage that communicates with the interior of the module case and through which smoke from the plurality of power storage cells flows is formed inside the first protrusion. Energy storage device.

4. The electricity storage device according to claim 2 or 3, the second protrusion is formed on the second outer surface, A cooling passage through which a refrigerant for cooling the plurality of power storage cells flows is formed inside the second protrusion portion so as to extend along the first direction without communicating with the inside of the module case. Energy storage device.

5. The power storage device according to claim 1 or 2, the storage case includes a case body including the first inner surface and the second inner surface, At least the outer surfaces of the case body of the storage case are flat. Energy storage device.

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