Battery module

Abstract

To provide a battery module that can control displacement and load changes due to swelling of battery cells by reducing the thickness of an end plate without arranging a separate buffer member between the battery cells.SOLUTION: A battery module comprises: battery cells aligned in a first direction; a pair of end plates respectively disposed outside outermost battery cells among the battery cells; a pair of sub-end plates disposed between respective ones of the end plates and the outermost battery cells; and elastic members respectively inserted between the end plates and the sub-end plates to elastically support the end plates and the sub-end plates.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE An embodiment of the present invention relates to a battery module capable of maintaining proper pressure between cells. [Background technology]

[0002] The battery module includes a plurality of battery cells arranged in one direction, and the plurality of battery cells are configured to be connected in series or parallel depending on a required output voltage or a required charge / discharge capacity.

[0003] When a battery cell is charged and discharged, gas may be generated due to a chemical reaction. As the cycle progresses, the generated gas may cause the width of the battery cell to increase, which is called swelling. As one method for suppressing swelling, a method in which the end plates of the battery module constrain the battery cells in the swelling direction has been introduced. However, as the cycle progresses, the pressure applied to the battery cells gradually increases. This makes it difficult to maintain an appropriate pressure between the battery cells uniformly from the start of the battery's life to its end. In addition, since the end plates alone must withstand the swelling pressure, the thickness of the end plates must increase. This makes it difficult to construct a compact battery module, leading to increased manufacturing costs.

[0004] The above information disclosed in this Background of the Invention is intended to enhance the understanding of the background of the invention and, therefore, may include information that does not constitute prior art. Summary of the Invention [Problem to be solved by the invention]

[0005] An embodiment of the present invention provides a battery module that can adjust for changes in displacement and load caused by swelling of battery cells by reducing the thickness of end plates without disposing a separate buffer member between battery cells. [Means for solving the problem]

[0006] A battery module according to one embodiment of the present invention includes a plurality of battery cells aligned in one direction, a pair of end plates each disposed outside an outermost battery cell among the plurality of battery cells, a pair of sub-end plates disposed between the end plates and the outermost battery cell among the battery cells, and a plurality of elastic members inserted between the end plates and the sub-end plates to elastically support the end plates and the sub-end plates relative to each other.

[0007] A battery module according to another embodiment of the present invention may further include a pair of side plates disposed to face each other in a direction perpendicular to the alignment direction of the plurality of battery cells.

[0008] The end plate and the side end plate may each be in the shape of a rectangular plate.

[0009] One of the end plate and the sub-end plate may be formed with a cylindrical elastic member receiving portion configured to receive one end of the elastic member, and the other may be formed with a groove in which the other end of the elastic member is seated.

[0010] The elastic member may include a circular disc spring that is convex in one direction.

[0011] Each of the elastic members may be comprised of a plurality of disc springs.

[0012] The multiple disc springs may be stacked in the same direction.

[0013] The disc springs may be stacked in different directions.

[0014] The elastic member may be a plurality of stacked disk springs, each pair of which is stacked in the opposite directions.

[0015] The elastic member may be a plurality of disk springs, each of which is stacked in pairs in different directions.

[0016] The elastic members may be arranged in odd numbers.

[0017] Alternatively, the elastic members may be arranged in an even number. Effect of the Invention

[0018] According to an embodiment of the present invention, the thickness of the end plate can be reduced to adjust displacement and load changes caused by swelling of the battery cells without disposing a separate buffer member between the battery cells. [Brief description of the drawings]

[0019] [Figure 1] 1 is a schematic perspective view of a battery module according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a plan view of a battery module according to an embodiment of the present invention. [Diagram 3] 1 is an exploded perspective view of a battery module according to an embodiment of the present invention; [Figure 4] 4 is an exploded perspective view of an end plate, a sub-end plate, and an elastic member of a battery module according to an embodiment of the present invention. FIG. [Diagram 5] 4 is a cross-sectional view of an elastic member of a battery module according to an embodiment of the present invention. [Figure 6] 6 is a cross-sectional view of an elastic member of a battery module according to another embodiment of the present invention. [Figure 7] 11 is a cross-sectional view of an elastic member of a battery module according to still another embodiment of the present invention. [Figure 8]11 is a cross-sectional view of an elastic member of a battery module according to still another embodiment of the present invention. [Figure 9] 13 is an exploded perspective view of an end plate, a sub-end plate, and an elastic member of a battery module according to another embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The embodiments of the present invention are provided to more completely explain the present invention to those having ordinary skill in the art, and the following embodiments can be modified into various different forms, and the scope of the present invention is not limited to the following embodiments. Rather, these embodiments are provided to make the present disclosure more faithful and complete, and to fully convey the idea of ​​the present invention to those skilled in the art.

[0021] In the following drawings, the thickness and size of each layer are exaggerated for convenience and clarity of description, and the same reference numerals in the drawings refer to the same elements. As used herein, the term "and / or" includes any one and all combinations of one or more of the listed items. In addition, in this specification, "connected" means not only when member A and member B are directly connected, but also when member A and member B are indirectly connected with member C interposed between them.

[0022] The terms used in this specification are used to describe specific embodiments and are not intended to limit the present invention. As used in this specification, the singular form may include the plural form unless the context clearly indicates otherwise. Also, as used in this specification, "comprise" and / or "comprising" specify the presence of a mentioned shape, number, step, operation, member, element, and / or group thereof, but do not exclude the presence or addition of one or more other shapes, numbers, operations, members, elements, and / or groups.

[0023] In this specification, terms such as first and second are used to describe various members, parts, regions, layers and / or portions, but it is clear that these members, parts, regions, layers and / or portions should not be limited by these terms. These terms are used only to distinguish one member, part, region, layer or portion from another region, layer or portion. Thus, a first member, part, region, layer or portion described below may refer to a second member, part, region, layer or portion without departing from the teachings of the present invention.

[0024] Spatial terms such as "Beneath," "Below," "Lower," "Above," and "Upper" are used to facilitate understanding of one element or feature from another element or feature shown in the drawings. Such spatial terms are used to facilitate understanding of the invention according to various process or use conditions of the invention, and are not intended to limit the invention. For example, when an element or feature in the drawing is turned over, an element or feature described as "beneath" or "below" becomes "upper" or "above." Thus, "beneath" is a concept that encompasses "upper" or "below."

[0025] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a battery module according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0026] 1 to 3, a battery module 10 according to an embodiment of the present invention may include a plurality of battery cells 100, a pair of end plates 300, and a side plate 500. Although not shown in the drawings, the battery module 10 may further include a top cover, a bottom plate, a bus bar, a circuit board, and the like. In addition, a sub-end plate 700 may be disposed between the end plate 300 and the battery cells 100. A plurality of elastic members 900 may be provided between the end plate 300 and the sub-end plate 700.

[0027] The battery cells 100 may have a rectangular parallelepiped shape and may be aligned in a row along a predetermined direction. In this case, the battery cells 100 may be arranged such that their relatively wide plate surfaces face each other.

[0028] Each battery cell 100 may include a rectangular parallelepiped-shaped case, an electrode assembly housed inside the case together with an electrolyte, and a cell cap for sealing the case.

[0029] The electrode assembly may be formed by sequentially winding or stacking a negative electrode plate, a separator, and a positive electrode plate. A negative electrode plate formed of a metal foil such as copper, a copper alloy, nickel, or a nickel alloy may be coated or coated with a negative electrode active material such as graphite or carbon. A positive electrode plate formed of a metal foil such as aluminum or an aluminum alloy may be coated or coated with a positive electrode active material such as a transition metal oxide. A blank portion in which the active material is not applied may be formed on each of the negative electrode plate and the positive electrode plate. A negative electrode tab may be connected to the negative electrode blank portion, and a positive electrode tab may be connected to the positive electrode blank portion. The negative electrode tab and the positive electrode tab connected in this manner may be electrically connected to a negative electrode terminal and a positive electrode terminal formed on a cell cap, respectively. The negative electrode terminal and the positive electrode terminal formed on the cell cap may be electrically connected to a bus bar.

[0030] A pair of end plates 300 and a pair of side plates 500 acting as a cell frame for aligning the battery cells 100 may be provided. The pair of end plates 300 are disposed on the outer sides of the battery cells 100 disposed at the outermost edge along the arrangement direction of the battery cells 100, i.e., the X-axis direction in FIG. 1. The pair of side plates 500 are disposed perpendicular to the end plates 300. The pair of end plates 300 are disposed to face each other with the battery cell 100 therebetween. The pair of side plates 500 are disposed to face each other with the battery cell 100 therebetween along the Y-axis direction in FIG. 1. In addition, the above-mentioned bus bar, a bus bar holder for supporting the bus bar, and a circuit board may be disposed on the battery cell 100, and a top cover may be disposed thereon. In addition, a bottom plate may be disposed on the lower part of the battery cell 100. Thus, the pair of end plates 300, the pair of side plates 500, the bottom plate, and the top cover may be combined with each other to form a case having a substantially rectangular parallelepiped shape. The battery cells 100, bus bars, bus bar holders, and circuit boards may be housed therein.

[0031] 1 to 3, a pair of sub-end plates 700 are disposed between the end plate 300 and the battery cell 100 disposed at the outermost position among the battery cells 100. The sub-end plate 700 may be disposed to contact an outer surface of the battery cell 100 disposed at the outermost position. The end plate 300 may be disposed to face the sub-end plate 700.

[0032] The end plate 300 and the sub-end plate 700 may have a rectangular plate shape. The rectangular shapes of the end plate 300 and the sub-end plate 700 may substantially correspond to the rectangular shapes forming the side surfaces of the battery cells 100.

[0033] A plurality of elastic members 900 are inserted between the end plate 300 and the sub-end plate 700. The end plate 300 and the sub-end plate 700 are elastically supported relative to each other by the plurality of elastic members 900. The end plate 300 may be configured to be fixed in the alignment direction of the battery cells 100, i.e., the X-axis direction in FIG. 1. Exemplarily, the end plate 300 may be configured to be limited in movement in the alignment direction of the battery cells 100 by being coupled with the side plate 500. The sub-end plate 700 may be configured to be movable in the alignment direction of the battery cells 100. That is, the sub-end plate 700 is merely interposed between the end plate 300 and the battery cell 100 and is not fixed. Therefore, when swelling of the battery cell 100 occurs, the sub-end plate 700 may be displaced depending on the swelling direction. In addition, the degree of compression of the elastic member 900 changes depending on the displacement of the sub-end plate 700.

[0034] The elastic members 900 may be provided in an odd or even number. Although five elastic members 900 are illustrated in Fig. 3 and Fig. 4, the number and arrangement of the elastic members 900 are not limited thereto. For example, according to other embodiments of the present invention, an even number of elastic members, such as six or eight, may be provided.

[0035] One end of the elastic member 900 is supported by the sub-end plate 700, and the other end is supported by the end plate 300. As shown in Fig. 4, the end plate 300 may be formed with a cylindrical elastic member receiving portion 310 that receives one end of the elastic member 900. The sub-end plate 700 may be formed with a circular groove 710 in which the other end of the elastic member 900 is seated. One end of the elastic member 900 is supported by the end plate 300 while being inserted into the elastic member receiving portion 310, and the other end is supported by the sub-end plate 700 while being positioned in the groove 710. Thus, both ends of the elastic member 900 are supported in a state of being firmly seated by the end plate 300 and the sub-end plate 700.

[0036] Contrary to the previous embodiment, a cylindrical elastic member receiving portion 710' may be formed in a sub-end plate 700', and a circular groove 310' may be formed in an end plate 300' (see FIG. 9).

[0037] Referring to Fig. 5, the elastic member 900 may be a circular disc spring 910 that is convex in one direction. One elastic member 900 may be composed of a plurality of disc springs 910. For example, Fig. 5 exemplarily illustrates a case in which one elastic member 900 is composed of two disc springs 910. In this case, as shown in Fig. 5, the disc springs 910 may be stacked in opposite directions. That is, the elastic member 900 may be formed by stacking two disc springs 910 such that the convex portions of the disc springs 910 are in contact with each other.

[0038] 6 to 8 show elastic members according to other embodiments of the present invention. As shown in FIG. 6, an elastic member 900a may be arranged such that a plurality of disc springs 910a are stacked in the same direction. Also, as shown in FIG. 7, an elastic member 900b may be formed by stacking a plurality of pairs 910b' each of which is made up of disc springs 910b stacked in opposite directions. That is, the elastic member 900b according to the embodiment of FIG. 7 has a form in which a plurality of elastic members 900 of FIG. 5 are stacked. Also, as shown in FIG. 8, an elastic member 900c may be formed by stacking a plurality of pairs 910c' each of which is made up of two disc springs 910c stacked in different directions.

[0039] As described above, the displacement and load of the battery cells and the sub-end plate can be controlled by various combinations of the number of disc springs, stacking direction, etc. Therefore, the appropriate pressure of the cells in the battery module can be maintained, and the deterioration of the battery cell life can be prevented. In addition, the breakage of the can and cell cap due to swelling of the battery cell can be prevented.

[0040] The elastic member 900 of the various embodiments described above may be disposed such that the direction of compression and restoration is the same as the alignment direction of the battery cells 100. In addition, the restoring force of the elastic member 900 acts in a direction to pressurize the battery cells 100 in a general use environment. When the battery cell 100 expands due to charging of the battery cell 100, the swelling force increases. At this time, the direction in which the battery cell 100 expands is toward the end plate 300. Therefore, when the battery cell 100 expands, the swelling force is transmitted to the sub-end plate 700. The swelling force transmitted to the sub-end plate 700 is absorbed by the elastic member 900 and can be maintained constant. In addition, since the swelling force is not transmitted to the end plate 300, the fixed state of the end plate 300 and the side plate 500 can be maintained. In addition, although the elastic member 900 is compressed by the swelling force, the force supporting the battery cell 100 is larger than that in the case where only the end plate 300 is provided. Therefore, it is possible to reduce the thickness of the end plate 300 for restraining the battery cell 100. It is possible to secure an installation space for the elastic member 900 and the sub-end plate 700 by the amount of the reduction in the thickness of the end plate 300. Therefore, it is possible to absorb the swelling force without increasing the size of the battery module 10.

[0041] Conversely, when the swelling of the battery cell 100 decreases due to discharging of the battery cell 100, the swelling force transmitted to the elastic member 900 decreases. Therefore, the compressed elastic member 900 presses the battery cell 100 while being restored.

[0042] In this manner, when there is no swelling, the elastic member 900 presses and supports the battery cell 100. When there is swelling, the elastic member 900 absorbs the swelling force and supports the battery cell 100. That is, when the swelling of the battery cell 100 increases and decreases, the elastic member 900 always supports the battery cell 100, so that the multiple battery cells 100 can be maintained in close contact with each other without being separated from each other. Therefore, an internal space can be secured by eliminating the buffer member between the cells, and the capacity of the battery cell 100 can be increased.

[0043] What has been described above is merely one embodiment for implementing a cylindrical secondary battery according to the present invention, and the present invention is not limited to the above-described embodiment. As claimed in the following claims, it can be said that the technical concept of the present invention is within the scope of the invention to the extent that anyone with ordinary knowledge in the field to which the invention pertains can make various modifications without departing from the gist of the present invention. [Explanation of symbols]

[0044] 10: Battery module 100: Battery cell 300: End plate 310: Elastic member housing 500: Side plate 700: Sub-end plate 710: Groove 900: Elastic material 910:Disc spring

Claims

1. A plurality of battery cells aligned in one direction; a pair of end plates disposed on outer sides of battery cells disposed at outermost edges of the plurality of battery cells; a pair of sub-end plates disposed between the end plates and a battery cell disposed at an outermost portion of the battery cells; a plurality of elastic members interposed between the end plate and the sub-end plate so as to elastically support the end plate and the sub-end plate relative to each other.

2. The battery module of claim 1 , further comprising a pair of side plates arranged to face each other in a direction perpendicular to the alignment direction of the plurality of battery cells.

3. The battery module according to claim 1 , wherein the end plates and the side end plates are each shaped like a rectangular plate.

4. 2. The battery module according to claim 1, wherein one of the end plate and the sub-end plate has a cylindrical elastic member accommodating portion configured to accommodate one end of the elastic member, and the other has a groove in which the other end of the elastic member is seated.

5. The battery module according to claim 4 , wherein the elastic member includes a circular disc spring that is convex in one direction.

6. The battery module according to claim 5 , wherein each of the elastic members is composed of a plurality of disk springs.

7. The battery module according to claim 6 , wherein the plurality of disc springs overlap in the same direction.

8. The battery module according to claim 6 , wherein the plurality of disc springs are stacked in different directions.

9. The battery module according to claim 6 , wherein the elastic member is formed by stacking a plurality of pairs of disc springs stacked in opposite directions.

10. The battery module according to claim 6 , wherein the elastic member is formed by stacking a plurality of disk springs, two of which are stacked in different directions.

11. The battery module according to claim 1 or 5, wherein the elastic members are arranged in an odd number.

12. The battery module according to claim 1 or 5, wherein the elastic members are arranged in an even number.

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