Power supply device

Abstract

In order to suppress the enlargement of the power supply device and suppress the heat transfer between adjacent battery cells, the power supply device has: a plurality of battery cells (1) whose outer shapes are square; a plurality of partitions (2) for insulating the adjacent battery cells (1); and a restraining member that aggregates the plurality of battery cells (1) and the plurality of partitions (2). Each partition (2) includes: a clamping plate portion (22A) disposed between adjacent battery cells (1); a sheet-like heat insulating member (24A) disposed between the clamping plate portion (22A) and the adjacent battery cells (1); a peripheral wall (26A) protruding from the clamping plate portion (22A) toward the adjacent battery cells (1) and defining a storage space for storing the adjacent battery cells (1); and a plurality of ribs (27A) provided on the inner side of the peripheral wall (26A). The plurality of ribs (27A) hold the heat insulating member (24A).

Description

Technical Field

[0001] The present invention relates to a power supply device having a plurality of battery cells. Background Art

[0002] In recent years, electric vehicles using power supply devices for propulsion have become popular. Electric vehicles are known to have various structures, for example, there are electric vehicles (BEV: Battery Electric Vehicle) equipped with a driving motor, hybrid vehicles (HEV: Hybrid Electric Vehicle) equipped with an engine in addition to the motor, etc. A plurality of battery cells are used in the power supply devices installed in these electric vehicles. Each battery cell is a secondary battery that can be charged and discharged, such as a lithium-ion battery and a nickel-metal hydride battery. In such a power supply device, it is desired that the space occupied by the power supply device is small, and it is required to improve the space efficiency. As a power supply device with excellent space efficiency, there is known a power supply device including a plurality of square batteries stacked in one direction, an insulating partition arranged between each battery cell, and a restraining member for aggregating the plurality of square batteries (Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2010-157450 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] It is known that if the secondary battery reaches a high temperature, various adverse conditions will occur. In particular, if the chemical reaction of the internal power generation element is promoted by the action of heat, there is a risk of further self-heating due to the heat generated by the chemical reaction. On the other hand, the power supply device of Patent Document 1 is configured so that the battery cells are arranged close to each other. Therefore, when a battery cell becomes self-heated due to some abnormality, the heat is transferred from the battery cell to the adjacent battery cell. In the case where the amount of heat transferred from the battery cell that has become an abnormal state to the adjacent battery cell is large, there is a risk that the chemical reaction of the internal power generation element of the adjacent battery cell will be promoted due to the transferred heat. In order to suppress such heat propagation, it is necessary to make the partition provided for insulation thicker, but such a structure will lead to the enlargement of the power supply device, resulting in a problem of reduced space efficiency.

[0008] The present invention has been made to solve the above-mentioned problems, and a main object of the present invention is to provide a power supply device having a structure that suppresses heat transfer between adjacent battery cells while suppressing an increase in size of the power supply device.

[0009] Solutions for solving problems

[0010] A power supply device according to one embodiment of the present invention comprises: a plurality of battery cells having a square shape; a plurality of partitions for insulating adjacent battery cells; and a restraining member that brings the plurality of battery cells and the plurality of partitions together. Each partition comprises: a clamping plate portion disposed between adjacent battery cells; a sheet-shaped heat insulating member disposed between the clamping plate portion and the adjacent battery cells; a peripheral wall that protrudes from the clamping plate portion toward the adjacent battery cells and defines a storage space for storing the adjacent battery cells; and a plurality of ribs disposed on the inner side of the peripheral wall. The plurality of ribs hold the heat insulating member.

[0011] Effects of the Invention

[0012] According to the power supply device of the present invention, the separator can maintain the required function and can thermally insulate adjacent batteries, thereby achieving the effect of suppressing the size of the power supply device and suppressing heat transfer between adjacent battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a perspective view of the power supply device according to the first embodiment of the present invention.

[0014] Figure 2 yes Figure 1 A three-dimensional diagram of a battery cell.

[0015] Figure 3 Yes means Figure 1 A perspective view of an example of a separator.

[0016] Figure 4 It is used to illustrate Figure 3 A sectional view of a power supply device in the shape of a partition.

[0017] Figure 5 Yes means Figure 1 A perspective view of an example of a separator.

[0018] Figure 6 It is used to illustrate Figure 5 A sectional view of a power supply device in the shape of a partition.

[0019] Figure 7 It is a perspective view of a power supply device according to a second embodiment of the present invention.

[0020] Figure 8 Yes means Figure 4 A perspective view of an example of a separator.

[0021] Fig. 9 Observe from another direction Figure 6 And the observed stereogram. DETAILED DESCRIPTION

[0022] First, the process of conceiving the structure of the heat insulating member of one embodiment of the present invention is described. As shown in Patent Document 1, in a typical power supply device, a plurality of battery cells are arranged in the same posture. An insulating partition is arranged between adjacent battery cells to prevent short circuits between adjacent battery cells. On the other hand, in recent years, as the capacity of battery cells has increased, the energy possessed by each battery cell has tended to increase.

[0023] As described above, the power supply device of Patent Document 1 is a structure in which battery cells are arranged close to each other. Therefore, when a battery cell becomes self-heated due to some abnormality, heat is transferred from the battery cell to the adjacent battery cell. In the case where the amount of heat transferred from the abnormal battery cell to the adjacent battery cell is large, there is a risk that the chemical reaction of the power generation element inside the adjacent battery cell will be promoted due to the transferred heat. When the capacity of the battery cell is high, the amount of heat transferred from the abnormal battery cell to the adjacent battery cell is relatively large, so this phenomenon may become a problem.

[0024] In view of this problem, the inventors of the present invention have studied a structure using a partition with thermal insulation. In the existing power supply device, the partition uses a resin with high formability so that it can be formed into a shape that can achieve various functions such as insulation of adjacent battery cells and prevention of short circuits caused by condensed water. Therefore, in order to improve the thermal insulation, it is necessary to make the material thickness of the partition thicker. However, if the thickness of the partition is large, it will lead to the enlargement of the power supply device, and there is a problem of reduced capacity per unit volume of the power supply device. On the other hand, as a component with high thermal insulation, there is a sheet-shaped thermal insulation component, but this thermal insulation component has low formability, so there is a problem that it is difficult to be formed into a shape other than a sheet. In view of such actual conditions, the inventors have studied a structure for being able to utilize a sheet-shaped thermal insulation component.

[0025] (First Embodiment)

[0026] Figure 1 FIG. 1 is a perspective view showing a power supply device 100 according to a first embodiment of the present invention. Figure 1As shown, the power supply device 100 has a plurality of battery cells 1, a plurality of partitions 2, and a restraining member 3 that aggregates the plurality of battery cells 1 and the plurality of partitions 2. The plurality of battery cells 1 are arranged along one direction. Each partition 2 is arranged between adjacent battery cells 1. The plurality of partitions 2 have sheet-like insulating members to prevent short circuits between adjacent battery cells 1. In addition, the partition 2 has insulating properties to suppress heat transfer between adjacent battery cells. The plurality of battery cells 1 are connected in series or in parallel by means of a bus bar (not shown). In the power supply device 100, the voltage and capacity of the power supply device are determined according to the number of battery cells 1 connected in parallel and the number of battery cells 1 connected in series. The battery cells 1 can be various secondary batteries such as lithium-ion secondary batteries and nickel-hydrogen batteries.

[0027] The insulating member included in the partition 2 is a sheet with a thickness of 0.1mm to 1.5mm, including a fiber sheet composed of woven fabric, non-woven fabric, etc., and a porous material between fibers adsorbed on the fiber sheet. The insulating member suitable for the embodiment of the present invention has a thermal conductivity of less than 0.02W / (m·K). The porous material is preferably a material with a void structure such as a dry gel and an aerogel. In particular, silica aerogel and silica dry gel have a nano-sized void structure that restricts the movement of air molecules and have excellent insulation performance. In addition, silica dry gel can stably maintain its structure relative to external pressure. Since the melting point of silica particles is relatively high, silica dry gel also has high heat resistance. Various fibers can be used to form the fiber sheet, and flame-retardant fibers with heat resistance can also be contained. As flame-retardant fibers, oxidized acrylic fibers, flame-retardant vinylon fibers, polyetherimide fibers, aromatic polyamide fibers, and glass fibers are known. In particular, by making the fiber sheet contain glass fibers, it is expected that the heat resistance can be improved while the stiffness can be increased and creep deformation can be suppressed. For the heat insulating member using the fiber sheet containing flame-retardant fibers, even if the battery cell is heated to a high temperature due to thermal runaway, it will not be damaged, and the conduction of heat energy can be stably blocked, thereby effectively preventing the induction of thermal runaway.

[0028] In addition, it is preferable that the fibers contained in the above-mentioned heat insulating member be synthetic fibers having a relatively fine fiber diameter. The heat insulating property of the heat insulating member is derived from the properties of the powder described later, and therefore, by using synthetic fibers having a relatively fine fiber diameter as the base material, the heat insulating material can contain a large amount of powder. The fiber sheet used in this embodiment is preferably 1 μm to 30 μm from the viewpoint of both thermal conductivity and productivity.

[0029] In addition, the above-mentioned heat insulating member can also be formed by adding a thermoplastic resin. The heat insulating member to which the thermoplastic resin is added can improve rigidity. It is also possible to impart various characteristics by coating the surface of the heat insulating member. For example, it is possible to cover it with a coating formed of aluminum oxide with a low emissivity to suppress the influence of radiation heat transfer of the heat insulating member. When forming the heat insulating member in this way, it is possible to maintain heat insulation, heat resistance, etc. by adjusting the additives and to appropriately impart physical properties according to the required performance.

[0030] like Figure 1 As shown, the restraining member 3 includes a pair of end plates 32 disposed at both ends of the stacked battery cells 1 in the stacking direction, and a plurality of tie bars 34 fixed to the pair of end plates 32. The ends of the tie bars 34 are connected to the end plates 32. The tie bars 34 are fixed to the end plates 32 by means of set screws 36.

[0031] The tie bar 34 is manufactured by processing a metal plate of a predetermined thickness into a predetermined width. The ends of the tie bar 34 are connected to the end plates 32 to connect the pair of end plates 32, thereby holding the battery cell 1 therebetween. The tie bar 34 fixes the pair of end plates 32 to a predetermined size, thereby suppressing the expansion of the battery cell 1 stacked therebetween. If the tie bar 34 is stretched, it is impossible to prevent the expansion of the battery cell 1. Therefore, the tie bar 34 is manufactured by processing a metal plate of a strength that does not stretch under the expansion pressure of the battery cell 1, such as a stainless steel plate such as SUS304, a steel plate, etc., into a width and thickness having sufficient strength.

[0032] also, Figure 1 The tightening strip 34 is fixed to the end plate 32 by a set screw 36, but it does not necessarily have to be fixed by a threaded connection member. Specifically, it can also be fixed by welding, a locking structure, etc. Figure 1 In the power supply device of the embodiment, the tightening strip 34 is fixed to the side of the end plate 32, but the fixing structure of the end plate and the tightening strip does not need to be limited to the structure shown in the figure. The required function of the tightening strip 34 is to limit the relative distance between the pair of end plates 32. The structure of the end plate 32 and the tightening strip 34 can be any structure as long as it can limit the displacement of the pair of end plates.

[0033] (Battery Cell)

[0034] like Figure 2 As shown, the battery cell 1 includes a rectangular outer can 12 and a sealing body 14 provided with positive and negative electrode terminals 16. In addition, the battery cell 1 has an electrode body accommodated in the outer can 12, and the outer can 12 is filled with an electrolyte. The battery cell 1 has the characteristics of expanding or contracting with charging, discharging, and deterioration.

[0035] The outer can 12 is formed into a box shape with an opening. The sealing body 14 is welded to the outer can 12 and closes the opening of the outer can 12. Specifically, the outer can 12 is made by deep drawing a metal plate such as aluminum, aluminum alloy, etc. The sealing body 14 is made of a metal plate such as aluminum, aluminum alloy, etc. in the same manner as the outer can 12. The sealing body 14 has positive and negative electrode terminals 16 fixed at both ends. The sealing body 14 is welded while being inserted into the opening of the outer can 12. Typically, the sealing body 14 is airtightly fixed to the outer can 12 by irradiating a laser beam on the boundary between the outer periphery of the sealing body 14 and the inner periphery of the outer can 12.

[0036] In addition, for a battery cell whose outer can and sealing body are made of metal, the metal is exposed on its surface. Such a battery cell is sometimes configured to cover the surface of the outer can with an insulating heat shrink tube to prevent short circuits caused by condensed water, etc. In this embodiment, a structure in which the surface of the outer can 12 is covered with a heat shrink tube can be used as needed.

[0037] (Partition 2A)

[0038] Figure 3 Yes means Figure 1 A perspective view of an example of a partition 2 is shown. Figure 3 and Figure 4 As shown, the separator 2A includes a clamping plate portion 22A sandwiched between adjacent battery cells 1 , a peripheral wall 26A protruding from the peripheral edge of the clamping plate portion 22A toward two adjacent battery cells 1 , and a sheet-like heat insulating member 24A arranged between the clamping plate portion 22A and the adjacent battery cells 1 .

[0039] The peripheral wall 26A protrudes from the clamping plate portion 22A toward the adjacent battery cell 1, and defines a storage space for storing the battery cell 1 on both sides of the partition plate 2A. The peripheral wall 26A is provided with a plurality of ribs 27A on the inner side to hold the battery cell 1 arranged in the storage space. Specifically, the peripheral wall 26A has opposing wall surfaces, and a plurality of ribs 27A are provided on the opposing wall surfaces.

[0040] It is preferable that the heat insulating member 24A uses the above-mentioned heat insulating member. The heat insulating member 24A is arranged in the storage space defined on the inner side of the peripheral wall 26A, and is clamped by a plurality of ribs 27A provided on the peripheral wall 26A. In addition, it is sufficient that there is only one heat insulating member 24A between adjacent battery cells 1, and the heat insulating member 24A is arranged in at least one of the pair of storage spaces provided in the partition 2A.

[0041] According to this structure, since the heat insulating member 24A is held by the plurality of ribs 27A, when the battery cells 1 are arranged in the storage space of the separator 2A, the heat insulating member 24A does not shift in position, and the assembly workability can be improved.

[0042] In addition, according to the above structure, the heat insulating member 24A is clamped by the plurality of ribs 27A provided on the opposite wall surfaces, so that a gap is formed between the opposite wall surfaces of the peripheral wall 26A and the heat insulating member 24A. Therefore, even if the clamping plate portion 22A, the battery cell 1 and the heat insulating member 24A are in close contact, the rise of condensed water due to the capillary phenomenon can be suppressed.

[0043] (Partition 2B)

[0044] Figure 5 Yes means Figure 1 A perspective view of an example of a partition 2 is shown. Figure 5 and Figure 6 As shown, the separator 2B includes a clamping plate portion 22B sandwiched between adjacent battery cells 1 , a peripheral wall 26B protruding from the peripheral edge of the clamping plate portion 22B toward two adjacent battery cells 1 , and a sheet-like heat insulating member 24B arranged between the clamping plate portion 22B and the adjacent battery cells 1 .

[0045] The peripheral wall 26B protrudes from the clamping plate portion 22B toward the adjacent battery cell 1, and defines a storage space for storing the battery cell 1 on both sides of the partition plate 2. The peripheral wall 26B is provided with a plurality of ribs 27B on the inner side to hold the battery cell 1 arranged in the storage space. Specifically, the peripheral wall 26B has opposite wall surfaces, and the plurality of ribs 27B are respectively provided on the opposite wall surfaces. In addition, a gap is formed between the clamping plate portion 22B and the plurality of ribs 27B.

[0046] The heat insulating member 24B is disposed in the storage space defined inside the peripheral wall 26B and is interposed between the clamping plate 22B and the plurality of ribs 27B. The heat insulating member 24B disposed in the storage space defined inside the peripheral wall 26B is held in a state where its displacement is restricted by the plurality of ribs 27B.

[0047] According to this structure, since the heat insulating member 24B is held by the plurality of ribs 27B, when the battery cells 1 are arranged in the storage space of the separator 2B, the heat insulating member 24B does not shift in position, and the assembly workability can be improved.

[0048] (Second Embodiment)

[0049] Figure 7 2 is a perspective view of a power supply device 200 according to a second embodiment of the present invention. In the following description, the same reference numerals are used for the same components as those of the first embodiment, and their description is omitted. The power supply device 200 according to the second embodiment is configured to form a cooling gap 4 between the partition 2 and the battery cell 1. Since the battery cell 1 deteriorates when the temperature reaches a high temperature, the battery cell 1 is cooled to suppress the degradation of the battery. Figure 7As shown in the example, it is preferable that the tie bar 34 be shaped so as to be able to introduce cooling air into the cooling gap 4 between the separator 2 and the battery cell 1. Figure 7 In the illustrated power supply device 200 , a pair of tie bars 34 are provided on one side surface, and the inlet of the cooling gap 4 faces between the pair of tie bars 34 .

[0050] (Partition 2C)

[0051] Figure 8 and Fig. 9 It is used to indicate Figure 7 A perspective view of an example of a partition 2 is shown. Figure 8 and Fig. 9 As shown, the partition 2C has a clamping plate portion 22C sandwiched between adjacent battery cells 1, and a peripheral wall 26C protruding from the peripheral edge of the clamping plate portion 22C toward two adjacent battery cells 1. The peripheral wall 26C protrudes from the clamping plate portion 22C toward the adjacent battery cells 1, and defines a storage space for storing the battery cells 1 on both sides of the partition 2C.

[0052] like Figure 8 As shown, the clamping plate portion 22C has a plurality of ribs 23C on one surface. The plurality of ribs 23C abut against the outer cans 12 of adjacent battery cells 1, thereby forming cooling gaps 4 between adjacent ribs 23C. Cooling gas flows through the cooling gaps 4, thereby cooling the battery cells 1.

[0053] The partition 2C has an insulating member 24C, which is arranged on the opposite side of the side of the clamping plate portion 22C on which the ribs 23C are formed. It is preferred that the insulating member 24C uses the above-mentioned insulating member. The insulating member 24C is arranged in a storage space defined on the inner side of the peripheral wall 26C of the partition 2C. In this state, the battery cell 1 is arranged in the storage space. According to this structure, the insulating member 24C is provided on the surface of the clamping plate portion 22C that is located on the opposite side to the surface on which the plurality of ribs 23C are formed. Therefore, the insulating member 24C does not hinder the cooling of the battery cell 1 by the cooling air flowing in the cooling gap 4, and can suppress the heat transfer between adjacent battery cells 1.

[0054] In addition, if Fig. 9As shown, the peripheral wall 26C is provided with a plurality of ribs 27C on the inner side. Specifically, the peripheral wall 26C has opposite wall surfaces, and the plurality of ribs 27C are respectively provided on the opposite wall surfaces. In addition, a gap is formed between the clamping plate portion 22C and the plurality of ribs 27C. The partition 2C includes an insulating member 24C disposed on one surface of the clamping plate portion 22C. The insulating member 24C is disposed in a storage space defined on the inner side of the peripheral wall 26C, and is between the clamping plate portion 22C and the plurality of ribs 27C. The displacement of the insulating member 24C disposed in the storage space defined on the inner side of the peripheral wall 26C is restricted by the plurality of ribs 27C.

[0055] According to this structure, since the heat insulating member 24C is held by the plurality of ribs 27C, when the battery cells 1 are arranged in the storage space of the separator 2C, the heat insulating member 24C does not shift in position, and the assembly workability can be improved.

[0056] The power supply device of the above structure has: a plurality of battery cells, which are square in shape; a plurality of partitions, which are used to insulate adjacent battery cells; and a restraining member, which brings together the plurality of battery cells and the plurality of partitions. Each partition includes: a clamping plate portion, which is arranged between adjacent battery cells; a sheet-like insulating member, which is arranged between the clamping plate portion and the adjacent battery cells; a peripheral wall, which protrudes from the clamping plate portion toward the adjacent battery cells; and a plurality of ribs, which are arranged on the inner side of the peripheral wall. The plurality of ribs hold the insulating member. According to this structure, the partition can maintain the required function and can insulate adjacent batteries from each other. Therefore, the power supply device of this structure can suppress the enlargement of the power supply device and can suppress the heat transfer between adjacent battery cells.

[0057] The present invention has been described above based on the embodiments. These embodiments are for illustration only, and it is understood by those skilled in the art that various modifications may exist in the combination of the above-mentioned components and processing procedures, and such modifications are also within the scope of the present invention.

[0058] Description of Reference Numerals

[0059] 1. Battery cell; 12. Outer can; 14. Sealing body; 16. Electrode terminal; 2. 2A, 2B, 2C, partition; 22A, 22B, 22C, clamping plate; 23C, rib; 24A, 24B, 24C, insulating member; 26A, 26B, 26C, peripheral wall; 27A, 27B, 27C, rib; 3. Restraining member; 32, end plate; 34, tightening strip; 36, positioning screw; 4. Cooling gap; 100, 200, power supply device.

Claims

1. A power supply device, characterized in that: The power supply device comprises: A plurality of battery cells, which are square in shape; A plurality of partitions for insulating adjacent battery cells, each of the partitions comprising: a clamping plate portion disposed between the adjacent battery cells; a sheet-shaped heat insulating member disposed between the clamping plate portion and the adjacent battery cells; a peripheral wall protruding from the clamping plate portion toward the adjacent battery cells and defining a storage space for storing the adjacent battery cells; and a plurality of ribs connected to the peripheral wall and provided on the inner side of the peripheral wall, wherein the plurality of ribs hold the heat insulating member, and a restraining member that aggregates the plurality of battery cells and the plurality of separators, The plurality of ribs hold the adjacent battery cells in a direction perpendicular to the stacking direction of the plurality of battery cells. A gap is formed between the wall surface of the peripheral wall on which the plurality of ribs are provided and the heat insulating member.

2. The power supply device according to claim 1, characterized in that: The power supply device includes a fiber sheet including main fibers and powder adsorbed and held on the fiber sheet.

3. The power supply device according to claim 2, characterized in that: The powder includes silica aerogel or silica xerogel.

4. The power supply device according to claim 2, characterized in that: The fiber sheet includes at least one of oxidized acrylic fiber, flame retardant vinylon fiber, polyetherimide fiber, aromatic polyamide fiber, and glass fiber.

5. The power supply device according to claim 2, characterized in that: The thermal insulation member further includes a thermoplastic resin.

Images