JP7256163B2 - battery module - Google Patents

Description

The present disclosure relates to battery modules.

Conventionally, in module batteries in which a plurality of batteries and a plurality of separators are alternately stacked along the arrangement direction, it has been proposed to provide grooves in the separators in order to improve heat dissipation of the batteries (Patent Document 1). ).

JP-A-2006-48996

In a battery module, a short circuit may occur inside the electrode assembly, and high-temperature gas may be suddenly generated inside the electrode. However, there is no gap between the electrode body and the housing (battery can) that accommodates it, and the generated high-temperature gas cannot reach the gas discharge valve and is discharged from the electrode body into a nearby space, resulting in There was a possibility that the body would melt and split open, causing fire to spread to adjacent batteries. The grooves formed in the separator described in Patent Document 1 are provided from the viewpoint of cooling performance, and cannot efficiently guide the gas generated when the battery is abnormal to the gas discharge valve. Cleavage cannot be prevented.

An object of the present disclosure is to provide a battery module that facilitates the discharge of gas generated inside an electrode assembly through a gas discharge valve provided in the battery, and that can prevent fire from spreading to other batteries due to the cracking of the housing. That is.

The present disclosure provides the following battery modules.
[1] A battery module in which a prismatic battery and a separator are stacked along the arrangement direction,
The prismatic battery has a gas discharge valve arranged on a surface parallel to the arrangement direction,
The separator has grooves on a surface facing the prismatic battery,
The battery module, wherein the grooves include a plurality of grooves formed in a direction parallel to the arranging direction in which one end of the groove is parallel to the arrangement direction.
[2] According to [1], two or more of the plurality of grooves have different lengths from one end to the other when the surface facing the prismatic battery is viewed from the arrangement direction. battery module.
[3] At least two of the plurality of grooves have different angles of straight lines connecting one end and the other of the end portions with respect to the surface facing the prismatic battery when viewed from the arrangement direction [1] ] or the battery module as described in [2].
[4] The plurality of grooves according to any one of [1] to [3], wherein the plurality of grooves extend toward the gas discharge valve and are formed so that the distance between them decreases as they approach the gas discharge valve. battery module.
[5] The prismatic battery includes a housing and an electrode body housed in the housing,
The housing is composed of a rectangular outer body and a sealing plate,
The rectangular exterior body is composed of a first side portion, a bottom portion, and a second side portion,
The gas discharge valve is arranged on the sealing plate,
The electrode body is composed of a first curved portion, a flat portion, and a second curved portion in order from the sealing plate side,
When viewed from the arrangement direction, the separator is
One end exists in a region between the sealing plate and the first curved portion, and the other end exists in a region between the flat portion and the first side portion or the second side portion. a first groove to
a second groove having one end in a region between the sealing plate and the first curved portion and the other end in a region between the second curved portion and the bottom portion; The battery module according to any one of [1] to [4], comprising:

According to the present disclosure, a battery module is provided in which gas generated inside an electrode assembly can be easily discharged from a gas discharge valve provided in the battery, and fire can be prevented from spreading to other batteries due to the cracking of the housing. be able to.

It is a schematic diagram showing an example of a battery module. FIG. 4 is a schematic cross-sectional view showing the inside of the prismatic battery viewed from the arrangement direction; It is a schematic cross-sectional view showing the inside of a prismatic battery viewed from the side of the prismatic battery. It is a schematic diagram showing an example of a separator seen from the arrangement direction. FIG. 4 is a schematic diagram schematically showing the positional relationship between the separators and the electrode bodies of the battery module viewed from the arrangement direction; 6 is a VI-VI cross-sectional view of the battery module shown in FIG. 5. FIG. FIG. 4 is a schematic diagram schematically showing another positional relationship between the separators and the electrode bodies of the battery module viewed from the arrangement direction; FIG. 8 is a cross-sectional view of the battery module shown in FIG. 7 taken along line VIII-VIII; It is a schematic diagram showing an example of a separator. FIG. 4 is a schematic diagram showing an example of a pattern of grooves in a separator; FIG. 4 is a schematic diagram showing an example of a pattern of grooves in a separator; FIG. 4 is a schematic diagram showing an example of a pattern of grooves in a separator; FIG. 4 is a schematic diagram showing an example of a pattern of grooves in a separator; FIG. 4 is a schematic diagram showing another example of a battery module; It is the schematic explaining the short internal short circuit test in an Example. 4 is a schematic diagram showing a separator used in Comparative Example 1. FIG. 4 is a schematic diagram showing a separator used in Comparative Example 2. FIG.

Embodiments of the present disclosure will be described below. In the embodiments described below, when referring to the number, amount, etc., the scope of the present disclosure is not necessarily limited to the number, amount, etc., unless otherwise specified. Also, in the following embodiments, each component is not necessarily essential for the present disclosure unless otherwise specified.

FIG. 1 is a diagram showing the basic configuration of a battery module 1. As shown in FIG. As shown in FIG. 1 , the battery module 1 includes prismatic batteries 100 and separators 200 . The prismatic battery 100 and the separator 200 may be stacked in direct contact with each other.

The prismatic battery 100 and the separator 200 are stacked along the arrangement direction (arrow DR1 direction). The battery module 1 may be formed by alternately stacking a plurality of rectangular batteries and a plurality of separators along the arrangement direction.

The prismatic battery 100 may be, for example, a lithium-ion battery, a nickel-metal hydride battery, or the like. The prismatic battery 100 is formed in a flat rectangular parallelepiped shape. A prismatic battery 100 includes a gas exhaust valve 110 , an electrode terminal 120 and a housing 130 . The gas exhaust valve 110 is arranged on the surface 101 parallel to the arrangement direction of the prismatic batteries 100 .

The housing 130 is composed of a rectangular exterior body 131 and a sealing plate 132 . Rectangular exterior body 131 includes a first side portion 133 , a bottom portion 134 and a second side portion 135 . The rectangular outer body 131 and the sealing plate 132 are preferably made of metal, preferably aluminum or an aluminum alloy. One surface of the sealing plate 132 in the battery module 1 is the surface 101 parallel to the arrangement direction.

The gas exhaust valve 110 can be arranged on a plane parallel to the arrangement direction (arrow DR1 direction). The gas exhaust valve 110 can be arranged, for example, on the vertically upward surface of the prismatic battery 100 . In the prismatic battery 100 , the gas exhaust valve 110 is arranged on the sealing plate 132 . High-temperature gas generated when an internal short circuit occurs in the prismatic battery 100 can be discharged from the housing 130 through the gas discharge valve 110 . The gas exhaust valve 110 breaks when the pressure inside the housing 130 exceeds a predetermined value. Thereby, the gas inside the housing 130 is discharged to the outside of the housing 130 . By discharging the high-temperature gas from the gas discharge valve 110, it is possible to prevent the fire from spreading to the adjacent prismatic batteries.

Electrode terminal 120 includes a positive terminal 121 and a negative terminal 122 . The electrode terminal 120 is formed on the sealing plate 132 . Housing 130 accommodates an electrode assembly and an electrolyte (not shown).

FIG. 2 shows the inside of the prismatic battery 100 viewed from the arrangement direction (arrow DR1 direction). The electrode body 300 is housed inside the housing 130 . Although the electrode body 300 is illustrated as a wound type, it may be a laminated (stacked) type. The wound electrode body 300 has a curved portion 301 , a flat portion 302 and a curved portion 303 . The electrode body 300 is connected to the positive terminal 121 by a positive collector (not shown). The positive electrode collector may be, for example, an aluminum plate. The electrode assembly 300 is connected to the negative terminal 122 by a negative collector (not shown). The negative electrode collector may be, for example, a copper plate.

FIG. 3 shows the inside of the prismatic battery 100 viewed from the side of the prismatic battery 100. FIG. The side surface of the prismatic battery 100 is the surface not provided with the gas discharge valve 110, and is the surface seen from the direction perpendicular to the arrangement direction (arrow DR3 direction). Normally, the surface of the electrode body 300 when viewed in the arrangement direction is in direct contact with the housing 130, and there is no gap between the surface of the electrode assembly 300 and the housing 130 when viewed in the arrangement direction. There is no escape for gas. At the curved portion 301 and the curved portion 303 , a gap (space) is generated between the electrode body 300 and the housing 130 due to the bending.

In the prismatic battery 100 shown in FIG. 3, one electrode body is housed in the housing 130, but a plurality of electrode bodies may be housed therein. When a plurality of electrode bodies 300 are accommodated in housing 130, electrode bodies 300 may be stacked in the arrangement direction (arrow DR1 direction).

FIG. 4 shows an example of a separator. Separator 200 may have, for example, a rectangular shape when viewed in the arrangement direction (arrow DR1 direction) (hereinafter also referred to as a plan view shape), or may be a rectangle having long sides and short sides. If both the separator 200 and the housing 130 have a rectangular plan view shape, the short side and long side dimensions of the separator 200 may be the same as the short side and long side dimensions of the housing 130, respectively, or It can be small.

The material forming the separator 200 may be made of, for example, thermoplastic resin or rubber. Examples of thermoplastic resins include polypropylene-based resins, polyethylene-based resins, polybutylene-based resins, polyamide-based resins, polyolefin-based resins, acrylic-based resins, and urethane-based resins. Examples of rubbers include ethylene propylene rubbers (EPM, EPDM) and the like. The compression modulus of the separator may be, for example, 2000 MPa or less, preferably 100 MPa or more and 1800 MPa or less, more preferably 500 MPa or more and 1300 MPa or less. The separator 200 may have a function as a heat insulating plate, for example.

The separator 200 can be manufactured, for example, by injection molding, or by forming grooves in a plate-like body made of the above material.

The dimension (hereinafter also referred to as thickness) of the separator 200 in the arrangement direction (arrow DR1 direction) may be, for example, 0.5 mm or more and 10 mm or less, preferably 1 mm or more and 5 mm or less.

The separator 200 has grooves 210 on the surface facing the prismatic battery 100 . The separator 200 may have grooves on both sides of the surface viewed from the arrangement direction of the separator 200 . If the grooves are provided on both sides, the gas can be easily discharged even when the prismatic batteries 100 are stacked on both sides of the separator 200 . The groove includes a plurality of grooves 211, 212, 213, 214 formed in a plane direction parallel to the arrangement direction in which one of the ends of the prismatic battery 100 is arranged. Since the separator has the groove, even if a short circuit occurs inside the electrode and gas is suddenly generated from the short circuit, the housing expands along the groove toward the gas discharge valve of the separator, thereby separating the electrode body and the housing. A gas outflow path to the gas discharge valve is formed between the body and the body, and the gas can be smoothly discharged from the gas discharge valve, preventing the spread of fire to other batteries due to the opening of the battery can. become able to.

In FIG. 4, the shapes of the plurality of grooves are all shown as linear, but the shapes of the plurality of grooves may be the same or different, and may be linear, curved or branched. or a combination of two or more thereof.

In the plan view shape of the separator 200, the width of the plurality of grooves may be, for example, 0.1 mm or more and 5 mm or less, preferably 0.5 mm or more and 4 mm or less, and more preferably 1 mm or more and 3 mm or less. The depth of the plurality of grooves may be, for example, 0.05 mm or more and 5 mm or less, preferably 0.1 mm or more and 3 mm or less, and more preferably 0.5 mm or more and 1.5 mm or less.

The number of the plurality of grooves may be, for example, 4 or more and 40 or less, preferably 4 or more and 20 or less.

In the shape of the separator 200 in plan view, when a perpendicular line P drawn from the side on which the gas discharge valve is arranged to the side opposite to that side is used as a boundary to define a first region A and a second region B, the first region The arrangement and shape of the plurality of grooves in A and second region B can be the same.

In the planar view of the separator 200, two or more of the plurality of grooves may have different lengths from one end of the groove to the other. When the shape of the groove is curved as will be described later, it refers to the linear distance connecting the end of the groove formed toward the gas discharge valve and the other end. In addition, when the shape of the groove is branched, it refers to the longest distance among the distances of straight lines connecting the end of the groove formed toward the gas discharge valve and one of the other ends. The plurality of grooves 211 and 212 shown in FIG. 4 have different lengths from one end of the groove to the other. Further, the plurality of grooves 213 and 214 shown in FIG. 4 have mutually different lengths from one end of the groove to the other. All of the grooves arranged in the first region A and the second region B may have different lengths. The length from one end of the groove to the other may be, for example, 30 mm or more and 500 mm or less.

In the plan view shape of the separator 200, two or more of the plurality of grooves are straight lines connecting one end and the other end of the grooves with respect to the surface 101 when the surface 101 facing the prismatic battery 100 is viewed from the arrangement direction. The angles can be different. The angles of the plurality of grooves 211 and 212 shown in FIG. 4 are different from each other. Further, the angles of the plurality of grooves 213 and 214 shown in FIG. 4 are different from each other. All of the grooves arranged in the first region A and the second region B may have different angles. The angle can be greater than 0 degrees and less than 90 degrees.

In the plan view shape of the separator 200, the plurality of grooves may be formed so that one end extends toward the gas discharge valve, and the distance between the grooves decreases as the gas discharge valve is approached. Intervals between the plurality of grooves 211 and 212 shown in FIG. 4 are formed so that the intervals between them become smaller as they approach the gas discharge valve. Also, like the gaps between the plurality of grooves 213 and 214 shown in FIG. 4, the gaps between them are formed so as to decrease as they approach the gas discharge valve. A plurality of grooves respectively arranged in the first region A and the second region B may be formed so that the distance between them decreases as they approach the gas discharge valve.

FIG. 5 schematically shows the positional relationship between the separators and the electrode bodies of the battery module viewed from the arrangement direction. As shown in FIG. 5 , when the battery modules are viewed from the arrangement direction, the separator 200 has one end in the region between the sealing plate 132 and the first curved portion 301 , and the flat portion 302 and the first curved portion 301 . First grooves 215 and 218 having the other end in the region between the first side portion 133 or the second side portion 135 and one end in the region between the sealing plate 132 and the first curved portion 301 There may be second grooves 216 , 217 with the other end in the area between the second curved portion 303 and the bottom portion 134 .

FIG. 6 is a sectional view taken along line VI-VI in FIG. As shown in FIG. 6, both ends of the second grooves 216, 217 may extend to the outside of the electrode body (beyond the bends 301 and 302).

FIG. 7 schematically shows another positional relationship between the separators and the electrode bodies of the battery module viewed from the arrangement direction. As shown in FIG. 7, when the battery module is viewed from the arrangement direction, the separator 200 has one end on the first curved portion 301 and a flat portion 302 and the first side portion 133 or the second side portion. 135 and one end on the first bend 301 and the other end on the second bend 303 . and second grooves 216, 217 to be provided.

FIG. 8 is a cross-sectional view taken along line VIII-VIII of FIG. As shown in FIG. 8, both ends of the second grooves 216, 217 can be on curved portions 301 and 303 of the electrode body.

FIG. 9 shows an example of a separator. The separator shown in FIG. 9 has a plurality of linear grooves on both sides viewed from the arrangement direction. The plurality of grooves are formed such that when the separator is stacked on the prismatic battery, one end of the grooves radially faces the surface of the prismatic battery on which the gas discharge valve is arranged. By forming the plurality of grooves radially, the gas generated when the electrode body is short-circuited tends to be easily discharged from the gas discharge valve.

10 to 13 show examples of groove shapes in plan view of the separator. As shown in FIG. 10, the shape of the groove may be curvilinear. As shown in FIG. 11, when the separator is stacked on the prismatic battery, the groove is formed so that one end of the groove is gathered in the depression provided on the side of the prismatic battery on which the gas discharge valve is arranged. may be formed so that one end of is directed radially toward the surface of the prismatic battery on which the gas discharge valve is arranged. As shown in FIG. 12, the shape of the grooves may be branched. As shown in FIG. 13, the shape of the groove may be formed such that the width of the groove becomes narrower toward the surface of the prismatic battery on which the gas discharge valve is arranged.

FIG. 14 shows another example of the battery module of the present disclosure. In the battery module 2 shown in FIG. 14, rectangular batteries 100 and separators 200 are alternately stacked. The prismatic battery 100 and the separator 200 may be sandwiched between a pair of end plates 400 and fixed. A plurality of prismatic batteries 100 sandwiched between the two end plates are pressed by the end plates 400 and restrained between the two end plates 400 .

End plates 400 are arranged at both ends of battery module 2 in the direction of arrow DR1 (arrangement direction). The end plate 400 is fixed to a base such as a case that houses the battery module 2 . Stepped portions 410 are formed at both ends of the end plate 400 in the direction of the arrow DR3.

Fastening portion 500 includes a restraining member 510 that connects two end plates 400 together, and a cover member 520 that is provided at the corner of end plate 400 . The restraint member 510 is attached to the stepped portions 410 respectively formed on the two end plates 400 . In the example of FIG. 14 , the restraining member 510 has a substantially L-shaped cross section, and the restraining member 510 is arranged at the corner of the prismatic battery 100 .

Engaging the restraining member 510 with the stepped portion 410 while applying a compressive force in the direction of the arrow DR1 to the laminate of the plurality of prismatic batteries 100, the separators 200 and the end plates 400, and then releasing the compressive force. As a result, a tensile force acts on the restraining member 510 connecting the two end plates 400 . As a reaction, the restraining member 510 pushes the two end plates 400 closer together.

The end plate 400 is made of, for example, aluminum die-cast material, aluminum extruded material, cast iron, or the like. The restraining member 510 is made of, for example, a general material such as SPFH590 material, a SUS material, or the like.

Although the embodiments of the present disclosure have been described above, the embodiments disclosed this time should be considered as examples in all respects and not restrictive. The scope of the present disclosure is indicated by the claims, and is intended to include all changes within the meaning and range of equivalents to the claims.

The present invention will be described in more detail below with reference to examples.

[Internal short-circuit test]
In the event of an internal short circuit in a non-aqueous electrolyte secondary battery, is it possible to prevent the lateral cracking of the non-aqueous electrolyte secondary battery and suppress the spread of fire by the gas induction effect of the grooves in the separator to the gas discharge valve? made an evaluation.
As shown in FIG. 15, a battery module 600 composed of non-aqueous electrolyte secondary batteries (dimensions: 91 mm long, 148 mm wide, and 26.5 mm thick) produced in Examples and Comparative Examples is sandwiched between fixing metal plates 601 and 602. Then, the non-aqueous electrolyte secondary battery 603 and the separators 604 and 605 were fixed with a predetermined load. As shown in FIG. 15, six holes 606 for nailing are provided on the surface of the fixing metal plate 602 and the separator 604 viewed from the arrangement direction. Next, a nail with a diameter of 1 mm was inserted into each of the six nail penetration holes 606 provided in the fixing metal plate 602 and the separator 604 until gas was generated due to an internal short circuit. The number of cells that cracked outside the 603 gas vent valve was counted.

<Example 1>
A separator made of polypropylene (thickness: 3 mm, dimensions: long side: 148 mm x short side: 85 mm, compression modulus: 1200 MPa) was prepared. In the contact surface of the separator shown in FIG. 9 with the non-aqueous electrolyte secondary battery, a pattern that draws a straight line in which the distance from one end to the other end toward the gas discharge valve is the shortest in any groove A plurality of grooves with a width of 2 mm and a depth of 1 mm were formed on both sides in a pattern (hereinafter also referred to as a radial pattern) to prepare a separator. A battery module was produced by sandwiching a non-aqueous electrolyte secondary battery between two separators. An internal short-circuit test was performed on the produced battery module. Table 1 shows the results.

<Comparative Example 1>
As shown in FIG. 16, on the contact surface between the non-aqueous electrolyte secondary battery and the separator, the distance from one end of each groove to the other end toward the gas discharge valve is the shortest straight line. A separator was produced in the same manner as in Example 1 except that a plurality of grooves were formed in a vertical pattern (hereinafter also referred to as a vertical linear pattern), and a non-aqueous electrolyte secondary battery was sandwiched between the separators to produce a battery module. An internal short-circuit test was performed on the produced battery module. Table 1 shows the results.

<Comparative Example 2>
As shown in FIG. 17, on the contact surface between the non-aqueous electrolyte secondary battery and the separator, the distance from one end of each groove to the other end toward the gas discharge valve is the shortest straight line. A separator was produced in the same manner as in Example 1 except that a plurality of grooves were formed in a pattern (hereinafter also referred to as a horizontal linear pattern), and a battery module was produced by sandwiching a non-aqueous electrolyte secondary battery between the separators. An internal short-circuit test was performed on the produced battery module. Table 1 shows the results.

<Comparative Example 3>
A battery module was produced in the same manner as in Example 1 except that the separator was used as it was without forming grooves, and an internal short-circuit test was conducted. Table 1 shows the results.

Reference Signs List 1, 2, 600 battery module, 100 prismatic battery, 101 plane parallel to arrangement direction, 110 gas discharge valve, 120 electrode terminal, 121 positive electrode terminal, 122 negative electrode terminal, 130 housing, 131 prismatic exterior body, 132 sealing plate, 133 first side portion 134 base portion 135 second side portion 200 separator 210 groove 211, 212, 213, 214 a plurality of grooves 215, 218 first groove 216, 217 second groove 300 electrode body , 301, 303 curved portion, 302 flat portion, 400 end plate, 410 stepped portion, 500 fastening portion, 510 restraining member, 520 cover member, 601, 602 fixing metal plate, 603 non-aqueous secondary battery, 604, 605 separator , 606 nail hole, A first area, B second area.

Claims (4)

A battery module in which a prismatic battery and a separator are stacked along the arrangement direction,
The prismatic battery has a gas discharge valve arranged on a surface parallel to the arrangement direction,
The separator has grooves on a surface facing the prismatic battery,
said groove comprises a plurality of grooves, one end of which is formed in the direction of a plane parallel to said arrangement direction in which said gas discharge valves are arranged;
The battery module, wherein the plurality of grooves extend toward the gas discharge valve, and are formed such that the distance between the grooves decreases as the gas discharge valve is approached. A battery module in which a prismatic battery and a separator are stacked along the arrangement direction,
The prismatic battery has a gas discharge valve arranged on a surface parallel to the arrangement direction,
The separator has grooves on a surface facing the prismatic battery,
said groove comprises a plurality of grooves, one end of which is formed in the direction of a plane parallel to said arrangement direction in which said gas discharge valves are arranged;
The prismatic battery includes a housing and an electrode body housed in the housing,
The housing is composed of a rectangular outer body and a sealing plate,
The rectangular exterior body is composed of a first side portion, a bottom portion, and a second side portion,
The gas discharge valve is arranged on the sealing plate,
The electrode body is composed of a first curved portion, a flat portion, and a second curved portion in order from the sealing plate side,
When viewed from the arrangement direction, the separator is
One end exists in a region between the sealing plate and the first curved portion, and the other end exists in a region between the flat portion and the first side portion or the second side portion. a first groove to
a second groove having one end in a region between the sealing plate and the first curved portion and the other end in a region between the second curved portion and the bottom portion; A battery module comprising: A battery module in which a prismatic battery and a separator are stacked along the arrangement direction,
The prismatic battery has a gas discharge valve arranged on a surface parallel to the arrangement direction,
The separator has grooves on a surface facing the prismatic battery,
said groove comprises a plurality of grooves, one end of which is formed in the direction of a plane parallel to said arrangement direction in which said gas discharge valves are arranged;
Two or more of the plurality of grooves have different lengths from one end to the other of the end portions when the surface facing the prismatic battery is viewed from the arrangement direction,
The battery module, wherein the plurality of grooves extends toward a gas exhaust valve. A battery module in which a prismatic battery and a separator are stacked along the arrangement direction,
The prismatic battery has a gas discharge valve arranged on a surface parallel to the arrangement direction,
The separator has grooves on a surface facing the prismatic battery,
said groove comprises a plurality of grooves, one end of which is formed in the direction of a plane parallel to said arrangement direction in which said gas discharge valves are arranged;
Two or more of the plurality of grooves have different angles of straight lines connecting one end and the other of the end portions with respect to the surface when the surface facing the prismatic battery is viewed from the arrangement direction,
The battery module, wherein the plurality of grooves extends toward a gas exhaust valve.

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