Battery pack

Abstract

Provided is a battery pack in which battery blocks are stacked in a plurality of layers, wherein a gas duct is secured and the battery pack is reduced in thickness. A battery pack (100) is provided with: a first battery block (20A) and a second battery block (20B) in which a plurality of secondary battery cells (1) are arranged; a spacer (30) disposed between the stacked first battery block (20A) and second battery block (20B); and an exterior case (10) that houses the first battery block (20A), the second battery block (20B), and the spacer (30). The separator (30) is provided with a partition plate (32) which is disposed so as to separate the first battery block (20A) from the second battery block (20B) and which divides a first space (31A) facing the first battery block (20A) and a second space (31B) facing the second battery block (20B), and the partition plate (32) forms a fracture region (33) at least in a region facing the secondary battery cell (1).

Description

Technical Field

[0001] The present disclosure relates to battery packs. Background Art

[0002] In electrical equipment using rechargeable secondary batteries such as lithium-ion secondary batteries, a battery pack containing multiple secondary battery cells in an outer casing is used to enable replacement of the secondary batteries (e.g., Patent Document 1). Electrical equipment driven by a battery pack includes various equipment such as electric carts and electric tools. Depending on the electrical equipment being driven, the battery pack is required to have higher output and higher capacity, and accordingly, the number of secondary battery cells used in the battery pack tends to increase. Therefore, Figure 7 As shown in the cross-sectional view of FIG, a battery pack 700 is formed by stacking battery blocks of horizontally arranged secondary battery cells 701 in an up-and-down manner. A resin spacer 730 is provided between the upper battery block 720A and the lower battery block 720B. On the other hand, the battery pack is also required to be small and light in order to facilitate portability and space for configuration.

[0003] On the other hand, secondary battery cells may have a high pressure inside the outer can due to some abnormality. Therefore, the secondary battery cells are configured as follows: a safety valve is provided in the outer can, and the safety valve opens in response to the high pressure, so that the high-temperature, high-pressure gas is discharged from the outer can. In the existing battery pack, a gas pipeline is provided so that when the gas is discharged from any secondary battery cell into the outer shell, the gas is safely discharged to the outside of the outer shell. For example, in Figure 7 In the battery pack 700 shown, gas ducts 731A and 731B are formed in a resin spacer 730 . The gas ducts 731A and 731B guide gas when it is exhausted from any of the secondary battery cells 701 .

[0004] Here, since the temperature and pressure of the discharged gas will also increase depending on the specifications such as the capacity of the secondary battery cell, the gas pipe for discharging the gas is also designed to have a certain internal height from the perspective of safety. Figure 7 As shown, in the structure in which battery blocks 720A and 720B are stacked in two layers, gas pipes 731A and 731B arranged between battery blocks 720A and 720B also need to be formed in two layers for each battery block. As a result, there is a problem that the volume of the gas pipe increases and the outer shape of the battery pack increases.

[0005] Prior Art Literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2013-84558 Summary of the invention

[0008] -Problems to be solved by the invention-

[0009] One of the objects of the present disclosure is to provide a battery pack in which a gas duct is ensured and a battery pack thickness is reduced in which a plurality of battery blocks are stacked.

[0010] -Methods for solving problems-

[0011] A battery pack involved in one embodiment of the present invention comprises: a first battery block and a second battery block, each of which has a plurality of secondary battery cells arranged therein; a spacer, which is arranged between the stacked first battery block and the second battery block; and an outer casing, which accommodates the first battery block, the second battery block, and the spacer, the spacer comprising: a partition plate, which allows the first battery block and the second battery block to be arranged separately, and divides a first space facing the first battery block and a second space facing the second battery block, the partition plate having a broken area formed at least in an area facing the secondary battery cells.

[0012] -Effects of the Invention-

[0013] According to the battery pack involved in one aspect of the present invention, in the event that high-temperature, high-pressure gas is released from any secondary battery cell, the first space and the second space can be connected by melting and penetrating the broken area of ​​the partition plate, and the gas can be guided to a wider space. As a result, the first space and the second space can be formed thinner, and it can contribute to the thinning of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a perspective view showing the battery pack according to the first embodiment.

[0015] Figure 2 yes Figure 1 An exploded perspective view of a battery pack.

[0016] Figure 3 yes Figure 2 An exploded perspective view of a battery module with an enlarged view of the main parts.

[0017] Figure 4 Observed from below Figure 3 An exploded perspective view of a battery module with an enlarged view of the main parts.

[0018] Figure 5 yes Figure 1 A vertical cross-sectional view of a battery pack taken along line VV.

[0019] Figure 6 yes Figure 5 An enlarged cross-sectional view of the main parts of the battery pack.

[0020] Figure 7It is a cross-sectional view showing a battery pack according to a comparative example.

[0021] Figure 8 yes Figure 7 An enlarged cross-sectional view of the main parts of the battery pack.

[0022] Fig. 9 yes Figure 6 FIG. 2 is an enlarged cross-sectional view of a further main part of the battery pack.

[0023] Fig.10 It is shown in Fig. 9 Figure 2 shows the state of thermal runaway in a battery pack.

[0024] Fig.11 It is shown in Figure 5 A cross-sectional view of a path for discharging high-pressure gas from an outer casing in a battery pack.

[0025] Fig.12 It is an enlarged cross-sectional view showing a battery holder of a battery pack according to a modification.

[0026] Fig.13 This is an enlarged perspective view showing a battery holder of a battery pack according to the second embodiment.

[0027] Fig.14 This is an enlarged perspective view showing a battery holder of a battery pack according to a third embodiment. DETAILED DESCRIPTION

[0028] The aspects of the present invention can also be identified by the following structures and features.

[0029] In a battery pack according to another aspect of the present invention in the above aspect, the spacer may have a positioning protrusion abutting against the first battery block and a positioning protrusion abutting against the second battery block integrally formed on an inner surface of a side wall.

[0030] In addition, in a battery pack according to another embodiment of the present invention, in any of the above embodiments, each secondary battery cell may have an outer canister in a cylindrical shape, and a safety valve is provided on one end face of the cylindrical outer canister, wherein the rupture region is configured such that when the safety valve opens and releases high-temperature gas, the safety valve ruptures due to the high-temperature gas and penetrates the partition plate.

[0031] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the break region may be a region where a region of the partition plate facing the secondary battery cell is formed to be thin.

[0032] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, end faces of the secondary battery cells constituting the first battery block and end faces of the secondary battery cells constituting the second battery block may be arranged to face each other with the spacer interposed therebetween.

[0033] Furthermore, in a battery pack according to another embodiment of the present invention, in any of the above embodiments, the safety valve may be provided on either the end surface of the secondary battery cell of the first battery block or the end surface of the secondary battery cell of the second battery block which are opposed to each other with the spacer interposed therebetween.

[0034] Furthermore, in another embodiment of the present invention, in any of the above embodiments, the battery pack may have either one of the end faces of the secondary battery cells of the first battery block and the end faces of the secondary battery cells of the second battery block facing each other with the spacer therebetween as the positive electrode or the other as the negative electrode.

[0035] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the rupture region may be formed in a circular shape.

[0036] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the thickness of the rupture region may be formed to be 0.1 mm to 1 mm.

[0037] Furthermore, in a battery pack according to another aspect of the present invention, in any of the above aspects, the partition plate may be formed so that a height of the first space and a height of the second space are substantially equal.

[0038] Hereinafter, the embodiments of the present invention will be described based on the accompanying drawings. However, the embodiments shown below are examples for concretizing the technical ideas of the present invention, and the present invention is not limited to the following contents. In addition, this specification does not limit the components shown in the technical solution to the components of the embodiments. In particular, the size, material, shape, relative configuration, etc. of the structural components recorded in the embodiments, as long as there is no definite record, are not intended to limit the scope of the present invention to this, but are just simple illustrative examples. In addition, the size, positional relationship, etc. of the components shown in the drawings are sometimes exaggerated for clear explanation. Further, in the following description, the same name and symbol represent the same or homogeneous components, and detailed description is appropriately omitted. Further, the elements constituting the present invention can be set to constitute multiple elements with the same components to use one component as multiple elements, and on the contrary, it can also be realized by sharing the function of one component with multiple components.

[0039] The battery pack of the present invention can be used as a driving power source for mobile bodies such as electric carts, electric scooters, and power-assisted bicycles, or as a power source for portable electrical devices such as wireless devices, electric cleaners, and electric tools, or as a backup power source for servers, power supply devices for homes, offices, and factories in a stationary storage type, and further as a driving power source for vehicles such as hybrid vehicles and electric vehicles. Hereinafter, as one embodiment of the present invention, a battery pack used as a driving power source for an electric cart will be described.

[0040] [Implementation Method 1]

[0041] Figure 1 to Figure 6 1 and 2 show a battery pack 100 according to Embodiment 1 of the present invention. In these drawings, Figure 1 A perspective view showing a battery pack 100 according to Embodiment 1 is shown. Figure 2 Show Figure 1 An exploded perspective view of the battery pack 100, Figure 3 Show Figure 2 An exploded perspective view of a battery module 2 with an enlarged view of the main parts, Figure 4 Shown as viewed from below Figure 3 An exploded perspective view of a battery module 2 with an enlarged view of the main parts, Figure 5 Show Figure 1 A vertical cross-sectional view of the battery pack 100 at line VV, Figure 6 Show Figure 5 1 and 2 are enlarged cross-sectional views of main parts of a battery pack 100 . The battery pack 100 shown in these figures includes an outer casing 10 , a battery module 2 , and a circuit board 3 .

[0042] (External casing 10)

[0043] The outer casing 10 accommodates the battery module 2 and the circuit board 3. Figure 1 As shown in FIG. 1 , the outer casing 10 is formed into a box shape. The outer casing 10 is divided into an upper casing 11 and a lower casing 12, for example. The outer casing 10 is made of a member with excellent insulation properties, for example, a resin such as polycarbonate or PC-ABS alloy. Figure 2 As shown in the exploded perspective view of FIG. 1 , an internal space for accommodating the battery module 2 and the circuit board 3 is provided inside the outer casing 10 .

[0044] (Battery module 2)

[0045] The battery module 2 is also called a core pack, etc., and is composed of a plurality of battery blocks 20. Figure 3 , Figure 4 , Figure 5In the example shown, the battery module 2 is composed of a first battery block 20A and a second battery block 20B. The first battery block 20A and the second battery block 20B are respectively composed of a plurality of secondary battery cells 1. The plurality of secondary battery cells 1 are connected in series and in parallel via lead plates. The number of series connections and the number of parallel connections can be arbitrarily set according to the required specifications. It is preferred that the first battery block 20A and the second battery block 20B use the same number of secondary battery cells 1. In addition, the number of series connections and the number of parallel connections are also preferably the same in the first battery block 20A and the second battery block 20B. Figure 3 , Figure 4 In the example shown in FIG. 1 , each battery block 20 uses a total of 90 secondary battery cells 1 , which are connected in series and in parallel, but the present invention is not limited to this structure.

[0046] Each battery block 20 includes a plurality of secondary battery cells 1. For example, the battery block 20 includes a battery holder that accommodates the secondary battery cells 1. The battery holder is provided with a plurality of accommodating tubes that individually accommodate the secondary battery cells 1. Such a battery holder can be made of a resin such as polycarbonate having excellent insulation properties. Figure 3 In the example, each battery block 20 is composed of 90 secondary battery cells 1, but the number of secondary battery cells constituting each battery block is not limited to this and can be set to any number. In addition, the battery block 20 can be easily reused by making the battery holder common. However, in some battery blocks, the number of secondary battery cells can also be changed.

[0047] In addition, Figure 3 In the examples such as above, an example in which the battery block is composed of two battery blocks, namely the first battery block 20A and the second battery block 20B, is described. However, the present invention does not limit the number of battery blocks to two, and of course, it may be three or more.

[0048] (Secondary battery cell 1)

[0049] The one or more secondary battery cells 1 can use square or cylindrical secondary battery cells. Figure 3 , Figure 4 In the example shown, cylindrical secondary battery cells 1 are arranged in a staggered manner in a vertical position for use. In addition, the number and configuration of the secondary battery cells 1 are not limited to this example, and any number and configuration can be appropriately adopted. Each secondary battery cell 1 has a positive and negative electrode. The positive and negative electrodes are preferably provided on one end surface of the secondary battery cell 1. The secondary battery cell 1 can appropriately utilize known secondary batteries such as lithium-ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries.

[0050] (Safety valve)

[0051] In addition, a safety valve is provided in the outer can of the secondary battery cell 1. The safety valve opens in response to a rise in the internal pressure of the outer can, and releases the gas inside the outer can to the outside.

[0052] (Circuit board 3)

[0053] Each of the first battery block 20A and the second battery block 20B is connected to the circuit board 3 via a lead plate. The circuit board 3 is mounted with a charge and discharge circuit for charging and discharging the secondary battery cell 1, a protection circuit for monitoring the voltage and temperature of the secondary battery cell 1 and cutting off the current in the event of an abnormality, etc. The circuit board 3 is composed of a glass epoxy substrate, etc.

[0054] (Spacer 30)

[0055] like Figure 5 , Figure 6 As shown, the spacer 30 is interposed between the first battery block 20A and the second battery block 20B. The spacer 30 is made of a member having excellent insulating properties, for example, a resin such as polycarbonate or PC-ABS alloy.

[0056] On the inner surface of the side wall 35 of the spacer 30, a positioning protrusion 36 abutting against the first battery block 20A and a positioning protrusion 36 abutting against the second battery block 20B are integrally formed. The first battery block 20A and the second battery block 20B respectively inserted from the openings on the upper and lower sides surrounded by the side wall 35 of the spacer 30 abut against the corresponding positioning protrusions 36, and the first battery block 20A and the second battery block 20B are configured to be stacked separately.

[0057] (Separator 32)

[0058] The spacer 30 includes a partition plate 32 that divides a first space 31A facing the first battery block 20A and a second space 31B facing the second battery block 20B. The partition plate 32 is preferably formed so that the height of the first space 31A and the height of the second space 31B are substantially equal. The partition plate 32 is preferably formed integrally with the spacer 30.

[0059] The first battery block 20A and the second battery block 20B are separated by the spacer 30, which helps to fix the interval between the first battery block 20A and the second battery block 20B. In addition, the first space 31A and the second space 31B are divided by the partition plate 32 formed in the spacer 30, which helps to configure the partition plate 32 at a suitable distance from the opposing surfaces of each battery block.

[0060] (Break Zone 33)

[0061] In addition, the partition plate 32 is provided with a break region 33 in the region facing the secondary battery cell 1. With such a structure, in the event that high-temperature, high-pressure gas is released from any secondary battery cell, the break region 33 of the partition plate 32 is broken and penetrated, so that the first space 31A and the second space 31B can be connected, and the gas can be guided to a wider space. As a result, the first space 31A and the second space 31B can be formed thinner, and it can contribute to the thinning of the battery pack.

[0062] Here, for comparison, Figure 7 The battery pack 700 shown in the cross-sectional view of FIG. 1 is described in comparison. Figure 7 The battery pack 700 has a resin spacer 730 disposed between the upper battery block 720A and the lower battery block 720B. Figure 8 As shown in the enlarged cross-sectional view of FIG, the gas pipeline is divided into two by the spacer 730, and the upper battery block gas pipeline 731A and the lower battery block gas pipeline 731B are respectively ensured. Therefore, even if the safety valve of the secondary battery cell 701 in either the upper battery block 720A or the lower battery block 720B is opened to discharge high-temperature and high-pressure gas, the gas can be guided along the discharge path through the upper battery block gas pipeline 731A and the lower battery block gas pipeline 731B.

[0063] However, depending on the specifications of the secondary battery cell 701, the temperature and pressure of the ejected gas may become high. In addition, the heat resistance of the resin spacer 730 is generally insufficient, so it is necessary to ensure the height of the gas ducts 731A and 731B to a certain extent. Therefore, when the battery blocks are stacked in multiple layers, it is necessary to ensure the gas ducts in each battery block, and the overall height becomes higher accordingly, which leads to the problem of increasing the size of the battery pack.

[0064] In contrast, in the battery pack 100 according to the present embodiment, Figure 3 As shown in the exploded perspective view of FIG. 1 , the spacer 30 is interposed between the first battery block 20A and the second battery block 20B, and as shown in FIG. Figure 6 As shown in the enlarged cross-sectional view of FIG. 3 , a partition plate 32 is provided on the spacer 30 to divide a first space 31A facing the first battery block 20A and a second space 31B facing the second battery block 20B. Figure 3 as well as Figure 6 As shown in the enlarged view of the main part of FIG. 1 , a break region 33 is formed in the region of the partition plate 32 facing the secondary battery cell 1. Fig. 9 As shown in the enlarged view of FIG. 1 , the rupture region 33 is formed to be a thin wall in which the wall thickness of the partition plate 32 is locally thinned in the region facing the secondary battery cell 1. Fig.10As shown, if the safety valve of any of the secondary battery cells opens due to some abnormality and high-temperature and high-pressure gas is blown out from the safety valve, the thin-walled rupture area 33 will melt and rupture due to the high temperature and pressure, breaking through the partition plate 32. Fig.10 In the example, the second space 31B of the second battery block 20B in the lower layer is connected to the first space 31A of the first battery block 20A in the upper layer through the fracture area 33. As a result, the high-temperature and high-pressure gas blown out from the secondary battery cell 1 is guided not only through the second space 31B, but also through the first space 31A. In other words, the area obtained by adding the first space 31A and the second space 31B is used as the gas guide path 34. If it is this structure, even if the height of the gas guide path 34 required for each battery block is not set between the battery blocks, 1 / 2 is prepared for each, and it is sufficient to ensure the height of the gas guide path 34 of one battery block in total, it is possible to achieve a low profile battery pack. Fig.11 As shown in the cross-sectional view, the high-temperature and high-pressure gas guided to the gas guide path 34 that combines the first space 31A and the second space 31B is guided by the gas guide path 34 divided in the outer shell 10, and is finally discharged to the outside from the gas discharge hole 14 formed on the surface of the outer shell 10.

[0065] In addition, it is desirable that the end faces of each secondary battery cell 1 constituting the first battery block 20A and the end faces of each secondary battery cell 1 constituting the second battery block 20B are arranged in a posture opposing each other with the spacer 30 interposed therebetween. Furthermore, it is desirable that a safety valve be provided on either side of the end faces of the secondary battery cells 1 of the first battery block 20A and the end faces of the secondary battery cells 1 of the second battery block 20B in a posture opposing each other with the spacer 30 interposed therebetween. For example, it is desirable that either side of the end faces of the secondary battery cells of the first battery block 20A and the end faces of the secondary battery cells of the second battery block 20B opposing each other be the positive electrode and the other side be the negative electrode. Generally, since the safety valve is provided on either side of the positive electrode or the negative electrode, by configuring the safety valve only on either side of the surfaces where the electrodes are opposed, it is possible to eliminate the situation where high-temperature and high-pressure gas is ejected from the end faces of both sides, thereby ensuring safety.

[0066] The partition plate 32 is preferably formed such that the surface on which the safety valve is provided is concave to form the rupture region 33. For example, when the safety valve is provided on the positive electrode side of the secondary battery cell 1, as shown in FIG. Fig. 9 As shown in the enlarged cross-sectional view of FIG, the side of the separator 32 facing the positive electrode is formed into a thin wall to serve as the rupture region 33. By doing so, the ejected gas is concentrated in the concave portion divided into the thin wall, and the rupture region 33 can be easily ruptured.

[0067] For example, in Figure 6As shown in FIG. 1 , in each battery block 20, the secondary battery cells 1 are arranged in a posture where the positive and negative electrodes appear alternately up and down in pairs. Figure 3 , Figure 4 As shown in the enlarged view of the main part of FIG. 1 , the fractured regions 33 formed in the partition plate 32 are also formed so as to appear alternately in every two columns on the partition plate 32 .

[0068] In addition, in Fig.12 When the secondary battery cells 1 are arranged with the positive and negative electrodes aligned on the same surface as in the illustrated battery pack 100 ′, a concave break region 33 is formed on the side of the separator 32 facing the positive electrode surface or the surface provided with the safety valve.

[0069] In addition, Figure 3 , Figure 4 In the example shown in FIG. 1 , the shape of the fracture region 33 is set to a circular shape, but the present invention is not limited to this structure. Fig.13 In the battery pack 200 according to the second embodiment shown, the fractured region 33B is octagonal. Alternatively, it may be a polygonal shape such as a quadrilateral or hexagonal shape, or an elliptical shape. Furthermore, when the secondary battery cell is square, it may be a rectangular shape corresponding to the square.

[0070] Furthermore, if Fig.14 As in the battery pack 300 according to the third embodiment shown, the break region 33C may be formed by a plurality of points. Each point forms a thin-walled portion.

[0071] The thickness of the thin-walled portion forming the rupture region 33 is designed according to the material and thickness of the partition plate 32, the capacity of the secondary battery cell used, and other specifications. It is preferably set to 20% to 60% of the average thickness of the rupture region 33. In addition, when the thickness of the partition plate 32 is 1.5 mm, it is set to 0.1 mm to 1 mm, preferably 0.3 mm to 0.5 mm.

[0072] In addition, in the above example, an example is described in which the thickness of the partition plate 32 is locally thinner to form the fracture area 33, but the present invention is not limited to this structure. For example, as long as insulation is fully achieved and it can be formed in size, the partition plate 32 can also be formed thinner as a whole.

[0073] In the above example, the battery pack is mounted on the electrical device to be driven, and power is supplied to the electrical device. In the case where the remaining capacity of the battery pack is low or the battery pack has deteriorated over the years, the battery pack can be replaced and the electrical device can continue to be used. However, the present invention does not limit the battery pack to a replaceable type that mainly accommodates secondary battery cells, but can also be applied to a method of accommodating secondary battery cells in the casing of the electrical device. In the present disclosure, the battery pack only needs to accommodate secondary battery cells in the casing, and the method of having secondary battery cells for driving built into the casing of the electrical device itself is also included in the battery pack. That is, the present invention is not limited to replaceable battery packs, but can also be applied to electrical equipment with built-in secondary battery cells.

[0074] Industrial Applicability

[0075] The battery pack of the present invention can be suitably used as a driving power source for mobile bodies such as electric carts and electric scooters, and can also be suitably used as a power source for wireless devices, electric cleaners, electric tools and other portable electrical equipment.

[0076] -Explanation of symbols-

[0077] 100, 100', 200, 300, 700... battery pack

[0078] 1…Secondary battery cell

[0079] 2…Battery Module

[0080] 3…Circuit board

[0081] 10…External housing

[0082] 11…Upper housing

[0083] 12…Lower housing

[0084] 14…Gas discharge hole

[0085] 20…battery block; 20A…first battery block; 20B…second battery block

[0086] 30…Spacer

[0087] 31A…first space; 31B…second space

[0088] 32…Separator

[0089] 33, 33B, 33C…fracture area

[0090] 34…Gas guide path

[0091] 35…Sidewall

[0092] 36…Positioning protrusion

[0093] 701…Secondary battery cell

[0094] 720A…upper battery block; 720B…lower battery block

[0095] 730…Spacer

[0096] 731A…gas pipes for the upper battery blocks; 731B…gas pipes for the lower battery blocks.

Claims

1. A battery pack comprising: The first battery block and the second battery block are respectively arranged with a plurality of secondary battery cells; a spacer disposed between the stacked first battery block and the second battery block; and The outer casing contains the first battery block, the second battery block and the spacer. The spacer includes a partition plate that arranges the first battery block and the second battery block separately and divides a first space facing the first battery block and a second space facing the second battery block. The separator has a break region formed at least in a region facing the secondary battery cell.

2. The battery pack according to claim 1, wherein: The spacer has a positioning protrusion formed integrally on an inner surface of a side wall thereof, the positioning protrusion being in contact with the first battery block and the positioning protrusion being in contact with the second battery block.

3. The battery pack according to claim 1, wherein: Each secondary battery cell has a cylindrical outer can, and a safety valve is provided on one end surface of the cylindrical outer can. The rupture region is configured such that when the safety valve is opened to release high-temperature gas, the rupture region is ruptured by the high-temperature gas to penetrate the partition plate.

4. The battery pack according to claim 3, wherein: The break region is a region where a region of the separator facing the secondary battery cell is formed to be thin-walled.

5. The battery pack according to claim 4, wherein: The end faces of the secondary battery cells constituting the first battery block and the end faces of the secondary battery cells constituting the second battery block are arranged in a posture facing each other with the spacer interposed therebetween.

6. The battery pack according to claim 5, wherein: The safety valve is provided on one of an end surface of a secondary battery cell of the first battery block and an end surface of a secondary battery cell of the second battery block which are in a posture facing each other with the spacer interposed therebetween.

7. The battery pack according to claim 6, wherein: One of the end faces of the secondary battery cells of the first battery block and the end faces of the secondary battery cells of the second battery block, which are in a posture facing each other with the separator interposed therebetween, serves as a positive electrode, and the other serves as a negative electrode.

8. The battery pack according to any one of claims 1 to 7, wherein: The fractured region is formed into a circular shape.

9. The battery pack according to any one of claims 1 to 7, wherein: The fracture region is formed to have a thickness of 0.1 mm to 1 mm.

10. The battery pack according to any one of claims 1 to 7, wherein: The partition plate is formed so that the height of the first space and the height of the second space are substantially equal.

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