KR20210090387A - Battery Pack Comprising Elastic Member - Google Patents

Abstract

The present invention relates to a battery pack which comprises: a battery cell module assembly in which a plurality of battery cells and cooling fins are closely arranged; a lower housing which receives the battery cell module assembly; a cooling plate which is positioned at an upper part of the battery cell module assembly; and a upper housing which is combined with an open upper side of the lower housing, wherein a buffering member comprising a plate spring is arranged at an inner lateral side of the lower housing. The battery pack can protect the battery cell module assembly from external impacts and can minimize a part remaining as a dead space in the battery pack.

Description

A battery pack including a cushioning member {Battery Pack Comprising Elastic Member}

The present invention relates to a battery pack including a buffer member, and specifically, a buffer member disposed between a housing and a battery cell module assembly to prevent flow of a battery cell module assembly accommodated in the battery pack and to protect from external impact. It is about the battery pack containing.

In recent years, lithium secondary batteries have been widely used not only in small devices such as portable electronic devices, but also in medium and large devices such as automobiles and power storage devices. As such, when a lithium secondary battery is used in a medium or large-sized device, a large number of lithium secondary batteries are electrically connected to increase capacity and output. In particular, a pouch-type secondary battery is widely used in these medium-to-large devices due to advantages such as easy stacking and light weight.

Conventionally, when a cell assembly is prepared by stacking a plurality of pouch-type secondary batteries and cartridges, and the battery pack is configured by accommodating them in a pack case, end plates are sometimes provided at both ends of the cell assembly in the stacking direction. The end plate is mainly made of a metal material, and may serve to protect and fix the secondary battery and the cartridge, and to maintain the surface pressure.

In addition, in order to prevent damage to the electrode lead welding part due to the movement of the battery cell, the pouch-type secondary battery was inserted into the cell frame and stacked, and then the cell assembly was assembled using bolts and nuts.

In this regard, FIG. 1 is a flowchart illustrating a manufacturing process of a conventional battery pack.

Referring to FIG. 1 , the battery cells 10 are stacked in a state accommodated in the cell cartridge 11 to constitute the battery cell module assembly 20 . In the battery cell module assembly 20, the end plates 30 disposed at both ends in the stacking direction are coupled using a bolt 31 and a nut, thereby fixing the shape of the battery cell module assembly 20.

A battery disconnecting unit (BDU) 40 is attached to an outer surface of one end plate 30 of the cell module assembly 20 , and an inter connect board (ICB) 41 is attached to a side facing the upper housing. Thereafter, the battery cell module assembly 20 and the housing 50 are coupled using a bolt structure in a state in which the ICB is attached to face the inner surface of the upper housing 50 .

A fastening member 52 through a fastener 53 is used to couple the lower housing 51 with the battery cell module assembly 20, and the upper housing 50 and the lower housing 51 are connected to the battery cell module assembly ( 20), the upper housing 50 and the lower housing 51 are bonded to each other by welding to form a sealing structure of the battery pack.

However, when bolts and nuts are used in the assembly process of the battery cell module assembly as described above, a dead space is inevitably generated due to a portion protruding from the outer surface of the battery cell module assembly, and thus the energy density of the battery pack. There is a problem with the lower

In this regard, Patent Document 1 relates to a battery pack that accommodates a plurality of secondary batteries in an internal space and includes a plurality of cartridges having fastening holes, wherein the secondary batteries are accommodated in the cartridge and a bolt passing through the fastening holes. and a structure assembled by a nut coupled to the bolt.

That is, Patent Document 1 does not solve the problem of dead space as described above.

Patent Document 2 includes a pair of cushioning members positioned between one surface of a plurality of battery cells and a side surface of the module cover, at least a portion of which is in contact with the battery cells and the side surfaces of the module cover, respectively, and the cushioning member is at least Disclosed is a battery module that is a leaf spring having one or more bent portions.

However, Patent Document 2 does not recognize a structure in which the leaf spring can be stably fixed on the module cover.

Accordingly, it includes a buffer member capable of stably fixing the battery cell assembly accommodated in the battery pack case and protecting the battery cell assembly from external impact, and including a structure capable of fixing the buffer member in the battery pack case. There is a need for a battery pack.

Korean Patent Publication No. 2016-0129597 (2016.11.09) Korean Patent Publication No. 2017-0135597 (2017.12.08)

The present invention is intended to solve the above problems, and the buffer member added to stably fix the battery cell module assembly accommodated in the battery pack is fixed in place in the battery pack housing, so that there is no fear of positional deviation. An object of the present invention is to provide a battery pack including a buffer member to safely protect a cell module assembly from external impact.

A battery pack according to the present invention for achieving this object includes a battery cell module assembly in which a plurality of battery cells and cooling fins are closely arranged, a lower housing accommodating the battery cell module assembly, and an upper portion of the battery cell module assembly. It may include a cooling plate positioned therein, and an upper housing coupled to an open upper surface of the lower housing, wherein a buffer member including a leaf spring is disposed on an inner surface of the lower housing.

The lower housing may be made of an aluminum material.

A guide rib for mounting the buffer member may be formed on the inner surface of the lower housing.

The buffer member may include a body portion made of a material having high rigidity to maintain the shape of the buffer member, and a leaf spring which is a portion in contact with the battery cell module assembly.

In addition, the body part includes a first surface to which the leaf spring is not attached, and a second surface and a third surface extending in the same direction from both ends in a direction perpendicular to the first surface, wherein the leaf spring includes: It may be located on the inner surface of the second surface and the third surface.

One end of the leaf spring is fixed to the body by welding, and the other end of the leaf spring is bent 180 degrees together with the end of the body.

Step portions for temporarily assembling the leaf spring before welding may be formed on the second surface and the third surface.

A through hole may be formed in the step portion, and a protrusion formed at an end of the leaf spring may be temporarily assembled by passing through the through hole.

The lower housing is composed of a rectangular-shaped lower surface, and two full-length side surfaces and two full-width side surfaces extending upward from the lower surface, and the buffer member is generally disposed on the inner surface of the lower surface and the two full-length side surfaces. It may be formed in a U-shape.

The leaf spring may be made of spring steel represented by KS standard number KSD 3701 or SPS 1 to SPS 9 or an alloy thereof as a material.

In the battery cell module assembly, an ICB may be assembled at both ends in the longitudinal direction.

The present invention also includes a device including the battery pack as an energy source.

As described above, since the battery pack according to the present invention does not include a structure such as a cartridge and an end plate for assembling a battery cell module assembly, a dead space that is inevitably generated by including a fastening structure of a bolt and a nut in the prior art This can be minimized.

In addition, since a method of attaching a battery cell and a heat dissipation fin using a double-sided tape or the like is used to assemble the battery cell module assembly, the assembly process is made easy and simple.

In addition, it is possible to protect the battery cell module assembly from external shocks and vibrations by using a buffer member including a leaf spring in the lower housing, and since a rib capable of fixing the buffer member is formed in the lower housing, the buffer member is provided. The process of fixing to the lower housing can be easily performed.

1 is a flowchart illustrating a manufacturing process of a conventional battery pack.
2 is a flowchart illustrating a manufacturing process of a battery pack according to the present invention.
3 is a vertical cross-sectional view of the battery pack of FIG. 2 and a partially enlarged view thereof.
4 is a perspective view and a partially enlarged view of a state in which a buffer member is added to the lower housing of FIG. 2 .
5 is a perspective view of a buffer member according to the present invention.
6 is a partially enlarged view of the buffer member.

Hereinafter, embodiments in which those of ordinary skill in the art to which the present invention pertains can easily practice the present invention will be described in detail with reference to the accompanying drawings. However, in the detailed description of the principle of operation of the preferred embodiment of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In addition, the same reference numerals are used throughout the drawings for parts having similar functions and functions. Throughout the specification, when a part is said to be connected to another part, it includes not only a case in which it is directly connected, but also a case in which it is indirectly connected with another element interposed therebetween. In addition, the inclusion of a certain component does not exclude other components unless otherwise stated, but means that other components may be further included.

Further, limitations described in the dependent claims may be applied to all embodiments described herein.

The present invention will be described along with detailed examples according to the drawings.

2 is a flowchart illustrating a manufacturing process of a battery pack according to the present invention.

Referring to FIG. 2 , the plurality of battery cells 100 and the cooling fins 102 are attached using double-sided tape, and the battery cell module assembly 120 is assembled so that they are closely aligned and fixed with each other. As described above, in the battery cell module assembly 120 according to the present invention, in the process of assembling the battery cell module assembly, only the battery cell 100 and the cooling fins 102 are fixed using a double-sided tape, and the battery cells are fixed. Omit the cartridge, frame, and end plate for Accordingly, it is possible to minimize the occurrence of dead space, which was conventionally caused by using bolts and nuts to fix them to the battery cell.

An inter connect board (ICB) 141 is attached to each of both ends of the battery cell module assembly 120 in the electric length direction from which the electrode terminal protrudes, so that the electrode lead and the power sensor are electrically connected. However, unlike shown in FIG. 2 , when the battery cell is a unidirectional battery cell rather than a bidirectional battery cell, the ICB may be attached to only one end of the battery cell module assembly 120 in the electric length direction.

Thereafter, optionally, a flexible flat cable (FFC) is combined with an end plate for electrical connection for detection of voltage, current and/or temperature, and is attached to the outer surface of the battery cell module assembly 120, and the x-axis is Insert the battery cell module assembly 120 into the lower housing 151 in a state in which the battery cell module assembly 120 is rotated 180 degrees.

The lower housing 151 may be made of an aluminum material, and compared to a housing made of a conventional plastic material, the weight of the housing itself is slightly increased, but compared to a structure in which an end plate is used to reinforce the rigidity of the battery module, Although the overall weight of the battery module is similar, there is an advantage that the rigidity is significantly improved.

The lower housing 151 includes a lower surface 155 of a rectangular shape, and two full-length side surfaces 156 and two full-width side surfaces 157 extending upwardly from the lower surface 155 .

The buffer member 170 disposed on the inner surface of the lower housing 151 includes a leaf spring, and the buffer member 170 is generally U-shaped to be disposed on the inner surface of the lower surface 155 and the two front-length side surfaces 156 . made in the form

The buffer member 170 includes a plate spring in the form of an arc convex in the inner direction of the lower housing 151 , and when the battery cell module assembly 120 is accommodated in the lower housing 151 , the plate spring in the form of an arc is the main body. It is deformed into a relatively flat shape while being pressed in the negative direction. However, in the state in which the battery cell module assembly 120 is mounted, the leaf spring of the cushioning member is not in a completely flat state, but maintains a gentle arch shape, and is spaced apart between the battery cell module assembly 120 and the lower housing 151 . space can be obtained. Accordingly, damage to the battery cell module assembly may be prevented by buffering pressure or vibration applied from the outside of the battery pack.

A cooling plate 180 is disposed on the upper portion of the battery cell module assembly 120 mounted on the lower housing 151 , and the battery cell module assembly 120 and the cooling plate 180 may be coupled by bolting. .

A Battery Disconnecting Unit (BDU) 140 equipped with a Battery Management System (BMS) may be disposed on the upper surface of the cooling plate 180 , and may function to block or flow current when a load is applied from the battery pack. have.

An upper housing 150 is disposed on the upper surface of the BDU, and the upper housing 150 and the lower housing 151 are coupled by a screw fastening method.

3 is a vertical cross-sectional view of the battery pack of FIG. 2 and a partially enlarged view thereof.

Referring to FIG. 3, FIG. 3 is a vertical cross-sectional view of the battery pack of FIG. 2 when viewed in the z-axis direction of FIG. It is seated on the inner surface of the side surface 156 in the longitudinal direction.

The buffer member 170 includes a body portion 171 made of a material with high rigidity to maintain the shape of the buffer member, and a plate spring 172 that is in contact with the battery cell module assembly.

The cooling fins 102 are disposed on the outermost side of the battery cell module assembly 120 arranged so that the battery cells 100 and the cooling fins 102 are in close contact with each other, and the outermost cooling fins 102 are connected to the leaf springs 172 . ) is in contact with

The material of the body part is not particularly limited as long as it is made of a material with high rigidity so that the size and shape are not deformed despite the elastic deformation of the leaf spring, and for example, steel may be used, Specifically, Posco standard CGCHS60DP or CGCHS340Y can be used.

3 shows the lower end of the buffer member and the lower portion of the battery cell module assembly spaced apart from each other for convenience of understanding, when the volume of the battery cell module assembly occupied inside the lower housing increases according to the design of the battery pack Of course, the separation space formed under the lower side of the battery cell module assembly and the lower side of the buffer member may be further narrowed.

The leaf spring 172 has a relatively small arc-shaped radius of curvature before the battery cell module assembly 120 is inserted into the lower housing, but when the battery cell module assembly 120 is inserted into the lower housing, the arch-shaped radius of curvature is This relatively large deformation, but not a flat state. Accordingly, the battery cell module assembly and the lower housing can be kept spaced apart with the arcuate leaf spring 172 interposed therebetween, and the leaf spring can protect the battery cell module assembly from external impact.

4 is a perspective view and a partially enlarged view of a state in which a buffer member is added to the lower housing of FIG. 2 .

Referring to FIG. 4 , three buffer members 170 are mounted on the lower housing 151 , but the position and number of the buffer members are not limited thereto. However, in consideration of the protection purpose of the battery cell module assembly, it is preferable that the spacing of the buffer members is uniformly arranged.

A guide rib 159 for mounting the buffer member 170 is formed on the inner surface of the lower housing 151, and the buffer member 170 width ( d1) and the spacing d2 of the guide ribs 159 are formed to have the same size, so that the buffer member can be stably fixed in a state inserted between the guide ribs. Accordingly, it is possible to prevent the buffer member from being detached after being mounted on the lower housing.

Figure 5 is a perspective view of the buffer member according to the present invention, Figure 6 is a partially enlarged view of the buffer member.

5 and 6 (a), the body portion is a first surface (171a) to the center without a leaf spring attached, extending in the same direction from both ends in a direction perpendicular to the first surface (171a) It includes a second surface 171b and a third surface 171c, and the leaf spring 172 is located on the inner surface of the second surface 171b and the third surface 171c.

The leaf spring is made of a convex shape in the form of an arch to absorb and buffer the shock applied to the battery cell module assembly, and is made of metal with high elasticity. The metal usable as the leaf spring is not particularly limited, and for example, spring steel represented by KS standard number KSD 3701 or SPS 1 to SPS 9 or an alloy thereof may be used as a material.

One end of the leaf spring 172 is welded to the body 171 to form a weld 173 , and the other end of the leaf spring 172 is bent 180 degrees together with the end of the body 171 .

Accordingly, when the battery cell module assembly is mounted on the lower housing and the leaf spring 172 is pressed, the end of the leaf spring becomes longer in the direction of the arrow in FIG. 6 (a) as shown in the arrow direction of FIG. 6 (a). The bent end may be extended so as to protrude from the end of the bent body part.

Alternatively, depending on the rigidity of the leaf spring, the end cannot move in a further extending direction as shown in Fig. 6 (a), and as shown in Fig. 6 (b), as the arch shape is pressed, it can extend only in the downward direction as in the direction of the arrow. However, in such a case, it is preferable that the bent portion of the leaf spring 272 before deformation is configured to be spaced apart from the bent portion of the body portion 271 .

On the other hand, a step portion 175 for temporarily assembling the leaf spring 172 before welding is formed on the second surface 171b and the third surface 171c, and a through hole is formed in the step portion 175. The bar, the protrusion 174 formed at the end of the leaf spring 172 may be temporarily assembled by being mounted through the through hole.

In this way, when the attachment is completed through the process of joining the leaf spring to the body by welding in a state where the leaf spring is temporarily assembled on the body, it is important to prevent the spring with elasticity from being bounced off before being welded to the body. can be prevented

As such, the present invention can minimize the occurrence of dead space by not using bolts and nuts in the process of assembling the battery cell module assembly. In addition, a buffer member is mounted on the lower housing to alleviate the shock applied to the battery cell module assembly, and a guide rib for fixing the buffer member is formed in the lower housing, so that the buffer member is mounted on the lower housing or the battery When the cell module assembly is mounted on the lower housing, it is possible to prevent the buffer member from being separated from the original position.

Those of ordinary skill in the art to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

10, 100: battery cell
11: cell cartridge
20, 120: battery cell module assembly
30: end plate
31: bolt
40, 140: BDU
41, 141: ICB
50, 150: upper housing
51, 151: lower housing
52: fastening member
53: fastener
102: cooling fins
155: if
156: side of the battlefield direction
157: side in the full width direction
159: guide rib
160: FFC
170: buffer member
171, 271: body part
171a: page 1
171b: page 2
171c: page 3
172, 272: leaf spring
173: weld
174: protrusion
175: step part
180: cooling plate
d1: the width of the buffer member
d2: spacing of guide ribs

Claims (12)

a battery cell module assembly in which a plurality of battery cells and cooling fins are closely arranged;
a lower housing accommodating the battery cell module assembly;
a cooling plate positioned above the battery cell module assembly; and
an upper housing coupled to an open upper surface of the lower housing;
includes,
A battery pack in which a buffer member including a leaf spring is disposed on an inner surface of the lower housing. The battery pack according to claim 1, wherein the lower housing is made of an aluminum material. The battery pack according to claim 1, wherein a guide rib for mounting the buffer member is formed on an inner surface of the lower housing. According to claim 1, wherein the buffer member,
A battery pack comprising a body portion made of a material having high rigidity to maintain the shape of the buffer member, and a leaf spring which is a portion in contact with the battery cell module assembly. 5. The method of claim 4, wherein the body portion,
a first surface to which the leaf spring is not attached, and
and a second surface and a third surface extending in the same direction from both ends in a direction perpendicular to the first surface,
The leaf spring is located on the inner surface of the second surface and the third surface. The battery pack according to claim 3, wherein one end of the leaf spring is fixed to the body by welding, and the other end of the leaf spring is bent 180 degrees together with the end of the body. The battery pack according to claim 5, wherein a step portion for temporarily assembling the leaf spring before welding is formed on the second surface and the third surface. The battery pack according to claim 7, wherein a through hole is formed in the step portion, and a protrusion formed at an end of the leaf spring passes through the through hole and is temporarily assembled. According to claim 1, wherein the lower housing is composed of a rectangular lower surface, and two full-length side surfaces and two full-width side surfaces extending upward from the lower surface,
The buffer member is a battery pack made of a U-shape as a whole so as to be disposed on the inner surface of the lower surface and the two front-length side sides. The battery pack according to claim 4, wherein the leaf spring uses spring steel represented by KS standard number KSD 3701 or SPS 1 to SPS 9 or an alloy thereof as a material. The battery pack according to claim 1, wherein the battery cell module assembly has ICBs assembled at both ends of the battery cell module assembly in the longitudinal direction. A device comprising the battery pack according to any one of claims 1 to 11 as an energy source.

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