CN210897379U

CN210897379U - Battery module

Info

Publication number: CN210897379U
Application number: CN201921648504.9U
Authority: CN
Inventors: 邵长健; 周锦兵
Original assignee: Dongguan Amperex Technology Ltd
Current assignee: Xiamen Xinnengda Technology Co Ltd
Priority date: 2019-09-29
Filing date: 2019-09-29
Publication date: 2020-06-30
Anticipated expiration: 2029-09-29

Abstract

The application relates to a battery module, it includes: a plurality of electric cores and at least one bolster that range upon range of setting in proper order. The bolster sets up between two at least in a plurality of electric cores, and elastic deformation can take place for the bolster to when electric core inflation, the bolster provides the inflation space, and the bolster recovers when electric core contracts. Wherein at least one of the thickness, length, and width of the buffer is associated with a corresponding one of the thickness, length, or width of the cell. When the buffer member deforms in the range of 0% to 85% of strain range, 0 to 1MPa of acting force is provided. The battery module bears certain pressure when the battery core is not charged, so that the whole structure of the battery module is compact and is in a compression state, and the battery core is allowed to expand to a certain degree when the battery module is charged. Therefore, the cycle life of the battery module is significantly extended.

Description

Battery module

Technical Field

The present invention relates to an energy storage device, and more particularly, to a battery having a rechargeable battery module, for example, a battery module used in an electric vehicle such as an electric bicycle or an electric car.

Background

Due to the increasing demand for energy conservation and environmental protection, electric vehicles such as electric bicycles and electric automobiles are increasingly widely used. For such electric vehicles, the battery has a very important role and meaning as a power source, which is directly related to the manufacturing cost, the service life, and the like of such electric vehicles. However, in the prior art, the battery has the problems of short service life, rapid capacity reduction along with the increase of charging times and the like.

Specifically, current electric vehicles (e.g., electric bicycles, tricycles, electric automobiles, etc.) generally employ a soft-packed lithium battery. However, the prior art soft pack lithium batteries have some disadvantages. For example, during charge and discharge cycles, the cell thickness becomes thicker due to the swelling of the cell or deformation of the cell pole piece caused by the lithium intercalation behavior of the negative electrode material, and thus the battery capacity rapidly decays, resulting in a shortened cycle life of the entire battery. In order to solve the problem of thickness thickening caused by cell expansion, an arrangement mode of reserving a gap between cells is generally adopted at present. But this construction again leads to other problems. For example, because there is not pressure between electric core and the electricity core, battery module overall structure is comparatively lax, and the electric core can freely expand in the use, also can lead to the cycle life of electric core to shorten like this.

SUMMERY OF THE UTILITY MODEL

The present application is directed to solving at least one of the above problems in the prior art. For this reason, the present application provides such a battery module: its electric core bears certain pressure when not charging promptly, therefore battery module overall structure is compact, be in the state of compressing tightly, and allows electric core to have the inflation of certain degree again when charging to along with going on of discharging, the in-process that electric core constantly contracts, certain pressure is still born to electric core, thereby continues to keep the state that is compressed tightly. In this way, the cycle life of the whole battery module is remarkably prolonged.

Some embodiments of the present application provide a battery module, which includes: a plurality of battery cells are sequentially stacked; and at least one buffer member, it sets up in a plurality of between at least two in the electric core, the buffer member can take place elastic deformation to when the electric core inflation, the buffer member provides the inflation space, and when the electric core contracts the buffer member recovers. Of course, reconstitution need not be 100% reconstitution, i.e., may not be fully reconstituted to its original state. During the recovery process, the buffer member is generally tightly attached to the battery cell adjacent to the buffer member. Wherein at least one of a thickness, a length, and a width of the buffer is associated with a corresponding one of a thickness, a length, or a width of the cell. When the buffer member deforms in the range of 0% to 85% of the strain range, a force of 0 to 1Mpa is applied to (for example, the battery cell adjacent to) the buffer member. This may be determined by the performance parameters of the buffer, or by both the performance parameters of the buffer and the size (e.g., thickness) of the buffer.

Specifically, at least one of a thickness, a length, and a width of the buffer is associated with a corresponding one of the thickness, the length, or the width of the cell. When the buffer member deforms in the range of 10% to 70% of the strain range, 0 to 0.5Mpa of acting force is provided for (for example, the battery cell adjacent to the buffer member); when the buffer member deforms in the range of 70% to 80% of the strain range, a force of 0.5 to 0.8Mpa is applied to (for example, the battery cell adjacent to) the buffer member.

According to one embodiment of the present application, a first number of the battery cells and a second number of the battery cells are respectively disposed on both sides of the buffer member, wherein the first number is greater than or equal to the second number, and the first number is N, and the thickness of the buffer member is N × N (0.12 to 0.18) times the thickness of the battery cells. Preferably, the thickness of the buffer is N x (0.14 to 0.16) times the thickness of the cell.

In some embodiments, the buffer is disposed between each adjacent cell of the plurality of cells, and the thickness of the buffer is 0.14 to 0.16 times the thickness of the cell. For example, the thickness of the buffer member is about 0.15 times the thickness of the battery cell.

According to another embodiment of the present application, the buffer member is disposed between each two of the plurality of battery cells and two adjacent battery cells, and the thickness of the buffer member is 0.28 to 0.32 times of the thickness of the battery cell. For example, the thickness of the buffer member is about 0.3 times the thickness of the battery cell.

Typically, the buffer comprises polypropylene, polyethylene or EVA foam.

According to an embodiment of the application, electric core and bolster all have flat structure, the length of bolster is 0.9 to 1.05 times of the length of electric core. Preferably, the length of the buffer member is 0.95 to 1.0 times of the length of the battery cell.

According to an embodiment of the present application, the battery cell and the buffer member both have a flat structure, and the width of the buffer member is 0.9 to 1.05 times the width of the battery cell. Preferably, the width of the buffer member is 0.95 to 1.0 times of the width of the battery cell.

According to some embodiments of the present application, the battery module further includes a cell support for supporting the cell, the cell support having a frame structure to cover the periphery of the cell to prevent the cell from being exposed.

According to some embodiments of the present application, the battery module further comprises a first end plate and a second end plate disposed opposite to each other, wherein each of the cell, the buffer member, and the cell support is located between and clamped by the first end plate and the second end plate.

According to some embodiments of the present application, the battery module further includes a fixing member for fixing the cell, the buffer member, and the cell holder between the first end plate and the second end plate. For example, the fixing member may be a ring-shaped binding member made of a steel band.

According to some embodiments of the present application, the battery module includes an elastically deformable spacer layer disposed between the first end plate and the cell holder adjacent thereto.

According to some embodiments of the present application, the battery module includes an elastically deformable spacer layer disposed between the second end plate and the cell holder adjacent thereto.

According to the battery module that this application provided, owing to be provided with the bolster (usually for the bubble cotton) that can take place elastic deformation between electric core and electric core to the size of bolster is correlated with the size (being at least one of thickness, length and width) of electric core, and the size of bolster has fine proportional relation with the size of electric core promptly, therefore in the battery module charges, the inflation process takes place for the electric core, the bolster takes place to warp at certain regional within range of meeting an emergency (for example 0% to 85%), and provides certain effort (for example 0 to 1Mpa) to the electric core during this period all the time. The buffer member can thus not only effectively provide a buffer with the cell, but also provide an appropriate pressure to the cell at the same time. And in the discharge process, along with the shrink of electricity core, the bolster recovers because of elasticity, and it still can exert certain pressure for electric core to make electric core continue to keep the state of being compressed tightly. The cycle life of the battery core and even the whole battery module is obviously prolonged by the mode.

Drawings

In order to more clearly illustrate the embodiments of the present application and the advantageous technical effects thereof, the following detailed description of the embodiments of the present application is made with reference to the accompanying drawings.

Fig. 1 is a schematic view of an overall structure of an embodiment of a battery module according to the present application;

fig. 2 is an exploded schematic view of the battery module shown in fig. 1 according to the present application;

fig. 3 is an exploded view of an embodiment of a sub-module in a battery module according to the present application;

fig. 4 is an exploded schematic view of another sub-module in a battery module provided according to the present application;

fig. 5 is an exploded schematic view of another sub-module of the battery module provided in accordance with the present application;

fig. 6 is a schematic diagram of the relationship between the strain range of a buffer in a battery module provided in accordance with the present application and the resulting compressive force (i.e., the force applied to, for example, cells adjacent thereto);

fig. 7A is a schematic view illustrating capacity retention of a battery module according to a preferred embodiment provided herein;

fig. 7B is a schematic view illustrating a capacity retention rate of a battery module according to a first comparative example provided in the present application;

fig. 7C is a schematic view of capacity retention ratio of a battery module according to a second comparative example provided in the present application;

fig. 8A is a schematic view illustrating pressure variation of a battery module according to a preferred embodiment provided herein;

fig. 8B is a schematic view illustrating a variation in pressure of the battery module according to the first comparative embodiment provided in the present application; and

fig. 8C is a schematic view illustrating pressure changes of the battery module according to the second comparative example provided in the present application.

Detailed Description

Embodiments of the present application are described in detail below with reference to the accompanying drawings. Aspects of the present application are more readily understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that these embodiments are exemplary, and are only used for explaining and illustrating the technical solutions of the present application, and not for limiting the present application. On the basis of these embodiments, a person skilled in the art may make various modifications and changes, and all technical solutions obtained by equivalent changes are within the scope of protection of the present application.

Fig. 1 illustrates a schematic view of the overall structure of a battery module provided according to the present application.

Referring to fig. 1, a battery module 100 provided according to an embodiment of the present application may include: cell 1, cell support 3,

end plates

41, 42, and mount 5. The battery module 100 may further include: a buffer (not labeled in fig. 1). In some embodiments, the battery module 100 may include a plurality of battery cells 1, a plurality of cell holders 3,

end plates

41, 42, and a plurality of fixing members 5. The battery module 100 may further include: a plurality of buffers (not labeled in fig. 1).

The battery cell 1 may include a flat plate-like structure. The battery cell 1 may include, but is not limited to, for example, a polygonal plate-shaped structure. The battery cell 1 may include, but is not limited to, a plate-like structure of a quadrangular shape, for example. The battery cell 1 may include, but is not limited to, for example, a rectangular plate-like structure. The battery cell 1 may include, but is not limited to, a flat plate-like structure of, for example, a square shape. The cell 1 may be used to store energy. Generally, in one battery module 100, the respective battery cells 1 have substantially the same size (length, width, and thickness), and thus, manufacturing and installation are facilitated.

The cell holder 3 may include a frame structure to cover the periphery of the cell 1 to prevent it from being exposed. For example, the battery cell 1 may be disposed in a frame of the cell holder 3. Generally, in a battery module, the number of the cell supports 3 is the same as that of the cells 1. I.e. one cell holder 3 corresponds to one cell 1. Of course, two adjacent battery cells 1 may share one cell frame 3. The cell holder 3 may include, but is not limited to, for example, a polygonal frame structure. The cell holder 3 may include, but is not limited to, for example, a quadrangular frame structure. The cell holder 3 may include, but is not limited to, for example, a rectangular frame structure. The cell holder 3 may include, but is not limited to, for example, a square frame structure. The structure of the battery cell support 3 can be matched with the structure of the battery cell 1. The cell support 3 may be located below the cell 1. The cell support 3 can be used for accommodating the cell 1. The cell support 3 may be used to support the cell 1. The cell support 3 may be used to fix the cell 1. The battery cell support 3 can be connected with the battery cell 1. The battery cell support 3 can be directly connected with the battery cell 1. The cell holder 3 may be directly connected to the cell 1 by, but not limited to, a joggle connection, for example. The cell holder 3 may be indirectly connected to the cell 1 through, but not limited to, the use of a connection member (not shown in fig. 1), for example. The attachment means may include, but is not limited to, for example, an adhesive or the like.

The end plate 41 may comprise a substantially flat plate-like structure. The end plate 41 may include, but is not limited to, a plate-like structure of a polygonal shape, for example. The end plate 41 may include, but is not limited to, a plate-like structure of a quadrangular shape, for example. The end plate 41 may include, but is not limited to, a flat plate-like structure of a rectangular shape, for example. End plate 41 may include, but is not limited to, a flat plate-like structure such as a square. The end plate 41 may have a configuration that matches the configuration of the cell holder 3 adjacent thereto. For example, the end plate 41 may be located below/outside (left side in fig. 1, 2) the cell holder 3. The end plate 41 may be used to fix the cell holder 3. The end plate 41 may be connected to the cell holder 3.

The end plate 42 may also comprise a generally flat plate-like structure. The end plate 42 may include, but is not limited to, a polygonal plate-like structure, for example. The end plate 42 may include, but is not limited to, a plate-like structure of, for example, a quadrilateral shape. The end plates 42 may include, but are not limited to, for example, rectangular, flat plate-like structures. The end plate 42 may include, but is not limited to, a flat plate-like structure such as a square. The structure of the end plate 42 may match the structure of the cell holder 3 adjacent thereto. For example, the end plate 42 may be located above/outside (right side in fig. 1, 2) the cell holder 3. The end plate 42 may be used to fix the cell holder 3. The end plate 42 may be connected to the cell holder 3.

The

end plates

41 and 42 may be oppositely disposed. The cell 1 may be located between the

end plates

41 and 42. The cell holder 3 may be located between the end plate 41 and the end plate 42. The

end plates

41 and 42 are disposed at outermost sides of the both ends. The

end plates

41 and 42 can clamp the cell support 3 and the cell 1.

The fixing member 5 may be fitted over the

end plates

41 and 42. The fixing member 5 may have a ring structure. The fixing member 5 may be a ring-shaped binding member. The fixing member 5 may fix the battery cell 1 and the battery cell support 3 between the end plate 41 and the end plate 42. The fixing member 5 may have elasticity. The securing member 5 may include, but is not limited to, for example, steel, rubber, or other suitable material.

Fig. 2 is an exploded view of the battery module according to fig. 1. Referring to fig. 2, a battery module 100 provided according to an embodiment of the present disclosure may include a battery cell 1, at least one buffer member 2, a cell support 3,

end plates

41 and 42, and a fixing member 5. In some embodiments, the battery module 100 may include a plurality of battery cells 1, a plurality of buffers 2, a plurality of cell holders 3,

end plates

41, 42, and a plurality of fixing members 5. In general, each cell 1, each buffer 2, and each cell holder 3 have substantially the same dimensions (length, width, and thickness). A plurality of electric core 1 can range upon range of setting in proper order, and bolster 2 sets up in a plurality of between two at least in electric core 1. The buffer member 2 is elastically deformable so that the buffer member 2 absorbs the expansion of the battery cell 1 when the battery cell 1 expands, and the buffer member 2 is restored to be closely attached to the battery cell 1 adjacent thereto when the battery cell 1 contracts. Wherein at least one of the thickness, length, and width of the buffer 2 is associated with a corresponding one of the thickness, length, or width of the battery cell 1, such that when the buffer 2 is deformed within a strain range of 0% to 85% (e.g., the thickness becomes 0% to 15% of its original thickness), a force of 0 to 1Mpa is provided to the battery cell 1 adjacent thereto. Therefore, when charging and in the process of expansion of the battery cell, the buffer piece always provides 0 to 1Mpa acting force for the battery cell. The buffer member 2 is thus able to not only effectively provide a buffer with the battery cell 1 but also provide an appropriate pressure to the battery cell 1 at the same time. And in the process of discharging, along with the shrink of electricity core 1, bolster 2 recovers because of the elasticity, and it still can exert certain pressure for electricity core 1 to make electricity core 1 continue to keep the state of being compressed tightly. In this way, the cycle life of the whole battery module is remarkably prolonged.

In other embodiments, the battery module 100 may include a spacer layer 2 'disposed between the first end plate 41 and the cell support 3 adjacent thereto, and may also include a spacer layer 2' disposed between the second end plate 42 and the cell support 3 adjacent thereto (see fig. 2). That is, in this embodiment, the battery module 100 may include a plurality of battery cells 1, a plurality of cell holders 3, a plurality of buffers 2, a plurality of partition layers 2',

end plates

41, 42, and a plurality of fixing members 5. The spacer layer 2' may also be made of the same material as the buffer member 2, and thus it is also elastically deformable, thereby also providing a buffer for the expansion of the battery cell 1.

The buffer 2 may comprise a plate-like structure. The buffer 2 may include, but is not limited to, a plate-like structure of a polygonal shape, for example. The buffer 2 may include, but is not limited to, a plate-like structure of a quadrangular shape, for example. The buffer 2 may include, but is not limited to, for example, a rectangular plate-like structure. The buffer 2 may include, but is not limited to, for example, a square plate-like structure. The buffer member 2 may be located between the battery cell 1 and the battery cell 1. The buffer member 2 may be used to provide a buffering action to the battery cell 1. The buffer member 2 can be used to provide a buffering action to the cell holder 3. The cushion member 2 may serve to provide a cushioning effect to the end plate 41. The cushioning member 2 may be used to provide cushioning to the end plate 42.

The buffer 2 may include, but is not limited to, for example,and (5) soaking cotton. The buffer member 2 may include, but is not limited to, for example, foam made of a microcellular foamed polyolefin-based material. The cushioning member 2 may comprise, but is not limited to, polypropylene, polyethylene or EVA foam, for example. The density of the buffer 2 can be 10-500 kg/m³In the meantime. The density of the buffer 2 is preferably 10-300 kg/m³In the meantime. The density of the buffer member 2 is preferably 20-60 kg/m³In the meantime. The hardness of the buffer 2 can be between 20-80 degrees (HC). The hardness of the buffer 2 may preferably be between 30-70 degrees (HC). The hardness of the cushion member 2 is preferably 50 to 70 degrees (HC). The buffer 2 may have air holes. The pore diameter of the air hole of the buffer 2 can be between 10-300 μm. The pore diameter of the air hole of the buffer 2 is preferably between 10 to 150 μm. The pore diameter of the buffer 2 is preferably between 10-80 μm.

The size of the buffer 2 may be associated with the size of the battery cell 1. In other words, the size of the buffer member 2 may be determined according to the size of the battery cell 1. As previously described, the individual cells in the same battery module 100 generally have substantially the same dimensions. The dimensions of the cell 1 may include the thickness. The dimensions of the cell 1 may include length. The dimensions of the cell 1 may include a width. The size of the buffer 2 may comprise the thickness. The size of the buffer 2 may comprise a length. The dimensions of the buffer 2 may comprise a width. The buffer 2 may have a certain elasticity. The buffer 2 can be changed by the pressing force. In some embodiments, when the battery cell 1 becomes thick due to swelling (charging process), the buffer member 2 may become thin due to being pressed by it, and the buffer member 2 may provide some buffer to the battery cell 1. In some embodiments, when the battery cell 1 becomes thinner due to shrinkage (discharge process), the buffer member 2 may restore to the original thickness (or close to the original thickness) under the elastic force, and the buffer member 2 may prevent the battery cell 1 from loosening from the battery cell support 3.

The barrier layer 2' may comprise a plate-like structure. The spacer 2' may include, but is not limited to, for example, a polygonal plate-like structure. The barrier layer 2' may include, but is not limited to, a quadrilateral plate-like structure, for example. The spacer 2' may include, but is not limited to, for example, a rectangular plate-like structure. The spacer 2' may include, but is not limited to, for example, a square plate-like structure. The interlayer 2' may be located below the cell support 3. The spacer layer 2' may be located between the cell holder 3 and the

end plates

41, 42. The barrier layer 2' may be used to provide a cushioning effect to the cell 1. The barrier layer 2' may be used to provide a cushioning effect to the cell holder 3. The barrier layer 2' may be used to provide cushioning to the end plate 41. The barrier 2' may be used to provide cushioning to the end plate 42.

The barrier layer 2' may include, but is not limited to, for example, foam. The barrier layer 2' may include, but is not limited to, for example, a foam made of a microcellular foamed polyolefin-based material. The barrier layer 2' may include, but is not limited to, for example, polypropylene, polyethylene, or EVA foam. The density of the interlayer 2' can be 10-500 kg/m³In the meantime. The density of the spacer 2' may preferably be between 10 and 300kg/m³In the meantime. The density of the spacer layer 2' may be preferably 20-60 kg/m³In the meantime. The hardness of the interlayer 2' may be between 20 and 80 degrees (HC). The hardness of the barrier layer 2' may preferably be between 30-70 degrees (HC). The hardness of the barrier layer 2' may be optimally between 50-70 degrees (HC). The barrier layer 2' may have pores. The pore diameter of the air holes of the interlayer 2' can be between 10 and 300 microns. The pore size of the spacer 2' is preferably between 10 and 150 μm. The pore size of the spacer layer 2' is preferably between 10 and 80 μm.

The size of the spacer layer 2' may be correlated with the size of the battery cell 1. In other words, the size of the spacer layer 2' may be determined according to the size of the battery cell 1. The dimensions of the cell 1 may include the thickness. The dimensions of the cell 1 may include length. The dimensions of the cell 1 may include a width. The dimensions of the spacer layer 2' may comprise a thickness. The dimensions of the barrier 2' may include length. The dimensions of the spacer layer 2' may comprise a width. The barrier layer 2' may have a certain elasticity. The barrier layer 2' may be altered by the force of the squeezing force. In some embodiments, when the cell 1 becomes thicker due to swelling, the separator layer 2 'may become thinner due to being pressed by it, and the separator layer 2' may provide some cushioning to the cell 1. In some embodiments, when the battery cell 1 becomes thinner due to shrinkage, the spacer layer 2 'may be restored to the original thickness (or close to the original thickness) by the elastic force, and the spacer layer 2' may prevent the cell support 3 from being loosened from the end plate 41. In some embodiments, when the cell 1 becomes thinner due to shrinkage, the spacer layer 2 'may be restored to the original thickness (or close to the original thickness) by the elastic force, and the spacer layer 2' may prevent the cell support 3 from being loosened from the end plate 42.

Referring to fig. 3, an exploded view of one embodiment of a sub-module in a battery module is provided according to the present application. As shown in fig. 3, the sub-module 300 may include one cell a. In some embodiments, sub-module 300 may include multiple cells A. And one battery module may include a plurality of sub-modules 300. In the sub-module 300, one unit a may include one battery cell 1, one buffer 2, and one battery cell holder 3. As described above, the battery cell support 3 may have a frame structure therein, and the battery cell 1 is installed in the frame of the battery cell support 3. The buffer member 2 is located on one side of the battery cell 1 so as to separate it from the adjacent battery cell 1 (i.e., of another unit a). In the battery module configured in this manner, the buffer 2 is disposed between each adjacent battery cell 1 of the plurality of battery cells 1 included in the battery module (i.e., a structure of "buffer/battery cell/buffer" is formed).

In the unit a, the size of the buffer member 2 may depend on the size of the battery cell 1. The dimensions of the cell 1 may include the thickness. The dimensions of the cell 1 may include length. The dimensions of the cell 1 may include a width. The size of the buffer 2 may comprise the thickness. The size of the buffer 2 may comprise a length. The dimensions of the buffer 2 may comprise a width. For the battery module, the ratio of the size of the buffer member 2 to the size of the battery cell 1 is very important. For example, if the buffer member 2 is too thin compared to the battery cell 1, it may not be effective to provide the buffer member 1 with a buffer because the buffer member 2 is deformed to a very limited extent and does not provide the battery cell 1 with a sufficient space for expansion thereof. For example, if the thickness of the buffer member 2 is too thick compared with the battery cell 1, the buffer member may occupy the space of the battery cell 1 unnecessarily, so that the capacity and the efficiency of the whole battery module are reduced, and the volume of the whole battery module is increased.

In the unit a, the thickness T1 of the buffer 2 may be associated with the thickness T0 of the battery cell 1. In the unit a, the thickness T1 of the buffer 2 may depend on the thickness T0 of the battery cell 1. In the unit a, preferably, the thickness of the buffer 2 is 0.12 to 0.18 times the thickness of the battery cell 1 (i.e., 0.12T0 ≦ T1 ≦ 0.18T 0). More preferably, the thickness of the buffer 2 is 0.14 to 0.16 times the thickness of the battery cell 1 (i.e., 0.14T0 ≤ T1 ≤ 0.16T 0). In the unit a, the thickness of the buffer member 2 is optimally about 0.15 times the thickness of the battery cell 1.

In the unit a, the length L1 of the buffer 2 may be associated with the length L0 of the cell 1, or may depend on the length L0 of the cell 1. Specifically, for example, the length L1 of the buffer 2 may be greater than or equal to 0.8 times the length L0 of the cell 1, and more preferably, may be greater than or equal to 0.9 times the length L0 of the cell 1. In a preferred embodiment of the present application, in the unit a, the length L1 of the cushion member 2 is 0.9 to 1.05 times the length of the battery cell 1 (i.e., 0.9L0 ≦ L1 ≦ 1.05L0), more preferably 0.95 to 1.0 times the length of the battery cell 1 (i.e., 0.95L0 ≦ L1 ≦ L0), and the length of the cushion member 2 is optimally about 0.95 times the length of the battery cell 1.

In the unit a, the width W1 of the buffer 2 may be associated with the width W0 of the cell 1, or may depend on the width W0 of the cell 1. In the unit a, the width W1 of the buffer 2 may be greater than or equal to 0.8 times the width W0 of the cell 1, and more preferably, may be greater than or equal to 0.9 times the width W0 of the cell 1. In a preferred embodiment of the present application, in the unit a, the width W1 of the cushion member 2 is 0.9 to 1.05 times the length of the cell 1 (i.e., 0.9W0 ≦ W1 ≦ 1.05W0), more preferably 0.95 to 1.0 times the length of the cell 1 (i.e., 0.95W0 ≦ W1 ≦ 1.0W0), and the width of the cushion member 2 is optimally about 0.95 times the width of the cell 1.

As described above, in the unit a, the thickness of the buffer member 2 may be about 0.15 times the thickness of the battery cell 1. The buffer member 2 having such a thickness can bring excellent technical effects: it not only can provide the buffering for electric core 1 effectively, can not occupy electric core 1's space unreasonably moreover, is favorable to improving the holistic capacity of battery module. In the unit a, in a case of matching with an appropriate length of the buffer member 2, but not limited to, for example, the length of the buffer member 2 may be about 0.95 times the length of the battery cell 1, and the battery module may further maintain the battery capacity above a certain level within a certain charging period (e.g., 4500 charging times). In the unit a, in a case of matching with an appropriate width of the buffer member 2, but not limited to, for example, the width of the buffer member 2 is about 0.95 times the width of the battery cell 1, and the battery module can also maintain the battery capacity above a certain level within a certain charging period (for example, charging 4500 times).

Referring to fig. 4, an exploded view of one embodiment of a sub-module in a battery module is provided according to the present application. As shown in fig. 4, the sub-module 400 may include one cell B. In some embodiments, sub-module 400 may include a plurality of cells B. In some embodiments, the sub-module 400 may include a plurality of cells B arranged periodically. In the sub-module 400, one unit B may include one battery cell 1, one battery cell 1', one battery cell holder 3, and one buffer 2. As described above, the battery cell support 3 may have a frame structure therein, and the battery cells 1 and 1' are respectively mounted in the frame of the battery cell support 3. Cell 1 'is located on one side of cell 1 so that they are stacked together, and buffer 2 is located on the other side of cell 1 so as to separate it from adjacent cells 1', 1 (i.e., of another unit B). The battery module configured in this manner is different from the battery module configured by the unit a, and a buffer 2 is provided between each two adjacent electric cores 1 in the plurality of electric cores 1 included in the battery module (i.e., a structure of "buffer/cell/buffer.

In the unit B, the size of the buffer member 2 may depend on the size of the battery cell 1. The dimensions of the cell 1 may include the thickness. The dimensions of the cell 1 may include length. The dimensions of the cell 1 may include a width. The size of the buffer 2 may comprise the thickness. The size of the buffer 2 may comprise a length. The dimensions of the buffer 2 may comprise a width. For the battery module, the ratio of the size of the buffer member 2 to the size of the battery cell 1 is very important. For example, if the buffer member 2 is too thin compared to the battery cell 1, it may not be effective to provide the buffer member 1 with a buffer because the buffer member 2 is deformed to a very limited extent and does not provide the battery cell 1 with a sufficient space for expansion thereof. For example, if the thickness of the buffer member 2 is too thick compared with the battery cell 1, the buffer member may occupy the space of the battery cell unnecessarily, so that the capacity and the performance of the whole battery module are reduced, and the volume of the whole battery module is increased.

In the unit B, the thickness T1 of the buffer 2 may be associated with the thickness T0 of the battery cell 1. In the unit B, the thickness T1 of the buffer 2 may depend on the thickness T0 of the battery cell 1. In the unit B, preferably, the thickness of the buffer 2 is 0.24 to 0.36 times the thickness of the battery cell 1 (i.e., 0.24T0 ≦ T1 ≦ 0.36T 0). More preferably, the thickness of the buffer 2 is 0.28 to 0.32 times the thickness of the battery cell 1 (i.e., 0.28T0 ≤ T1 ≤ 0.32T 0). In unit B, the thickness of the buffer member 2 is optimally about 0.3 times the thickness of the battery cell 1.

In the unit B, the relationship between the length and the width of the buffer 2 and the length and the width of the battery cell 1 is the same as the relationship between the length and the width of the buffer 2 and the length and the width of the battery cell 1 in the unit a, see above, and are not described herein again.

Similar to unit a, the use of the buffer 2 with the optimal thickness ratio (i.e. the thickness of the buffer 2 is 0.3 times the thickness of the battery cell 1) can bring about the superior technical effects: it not only can provide the buffering effectively for electric core 1, 1 ', can not unreasonable occupy electric core 1, 1 ''s space moreover, is favorable to improving the holistic capacity of battery module. In the unit B, in a case of matching with the buffer member 2 with a suitable length, but not limited to, for example, the length of the buffer member 2 may be about 0.95 times the length of the battery cell 1, 1', and the battery module may further maintain the battery capacity above a certain level within a certain charging period (e.g., 4500 charging times). In the unit B, in a case of matching with the buffer member 2 with a suitable width, but not limited to, for example, the width of the buffer member 2 is about 0.95 times the width of the battery cell 1, and the battery module can also maintain the battery capacity above a certain level within a certain charging period (for example, charging 4500 times).

As an alternative embodiment, a plurality of cells a and B may be included in the same battery module. Referring specifically to fig. 5, which is similar to fig. 3 and 4, an exploded view of an embodiment of a sub-module 500 in a battery module provided in accordance with the present application is also shown. As shown in fig. 5, the cells a and B are arranged periodically. Unit a includes a battery core 1, a buffer 2 and a battery core support 3. Cell 1 is mounted in cell holder 3, and buffer 2 is located on one side of cell 1, separating it from cells 1, 1' in unit B. In this arrangement, the buffer 2 has different numbers of cells on both sides (two cells on the left side (two cells in unit B) and one cell on the right side (cell in unit a)) to form a "cell/buffer/cell.

In this embodiment, the thickness T1 of the buffer 2 is still associated with the thickness T0 of the battery cells 1, 1'. Specifically, the thickness of the buffer member 2 is determined according to the number of cells on the side where the number of cells of the buffer member 2 is large. Assuming that the number of cells on the side with the larger number of cells is N, the thickness of the buffer member 2 is preferably N × (0.12 to 0.18) times the thickness of the cell 1. More preferably, the thickness of the buffer member 2 is N × of the thickness of the battery cell 1 (0.14 to 0.16). For example, in the embodiment of fig. 5, N ═ 2. Therefore, it is preferable that the thickness of the buffer member 2 is 0.24 to 0.36 times the thickness of the battery cell 1. More preferably, the thickness of the buffer member 2 is 0.28 to 0.32 times the thickness of the battery cell 1. Preferably, the thickness of the buffer member 2 is about 0.3 times the thickness of the battery cell 1.

In the above embodiments, the size of the spacer 2' disposed between the first end plate 41, the second end plate 42 and the cell holder 3 adjacent thereto may be designed with reference to the size of the buffer member 2. For example, the thickness of the spacer layer 2' is N × of (0.14 to 0.16) the thickness of the cell 1, where N is the number of cells 1 adjacent thereto. Preferably, the thickness of the spacer layer 2' is 0.15 times the thickness of the battery cell 1. The length and width of the spacer layer 2 'are 0.9 to 1.05 times of the length and width of the battery cell 1, respectively, and optimally, the length and width of the spacer layer 2' are 0.95 times of the length and width of the battery cell 1, respectively.

Referring to fig. 6, according to the battery module provided by the present application, since the thickness, length, and width of the buffer 2 are associated with the corresponding one of the thickness, length, and width of the battery cell 1, when the buffer 2 deforms in the range of 0% to 85% of the strain range, a force of 0 to 1Mpa is applied to (for example, the battery cell 1 adjacent to) the buffer; when the strain is deformed within the range of 10% to 70%, a force of 0 to 0.5Mpa is applied to (for example, the cell 1 adjacent to) the strain; when deformed within the strain range of 70% to 80%, a force of 0.5 to 0.8Mpa is applied to (e.g., to the cell 1 adjacent thereto). Such a range of force can greatly contribute to maintaining the capacity of the battery module and extending the life span thereof.

To more clearly illustrate the advantageous technical effects of the above embodiments of the present application, the following experimental data lists of the preferred embodiments and the comparative embodiments are provided in further conjunction with fig. 7A to 7C and 8A to 8C. Wherein T0, L0, and W0 respectively represent the thickness, length, and width of the cell.

TABLE 1

Referring to fig. 7A, the experimental data in the figure is based on experimental conditions: the battery module adopts a small module formed by the unit A. That is, adjacent cells are separated by 1 buffer, a buffer/cell/buffer … … cell/buffer stacking approach is used, and a module is secured using a strapping/end plate. The thickness of the buffer part 2 is 0.15 times of the thickness of the battery cell 1, the length and the width of the buffer part are respectively 0.95 times of the battery cell, the buffer part 2 is made of polypropylene foam, and the density of the buffer part 2 is 35-40 kg/m³(ii) a The hardness is 55 to 65 degrees (HC); the pore diameters are distributed within the range of 10-80 um and are intensively distributed within the range of 30-50 um. At this time, as can be seen from the figure, the capacity retention rate (SOH%) thereof gradually decreases. When it was charged 4500 times, its capacity retention rate still reached 80.93%, as shown in the above table.

As comparative example 1, if the thickness of the cushion member 2 is adjusted to 0.1 times the thickness of the battery cell 1 without changing other experimental conditions, the capacity retention ratio will obtain the experimental result shown in fig. 7B. As shown in the figure, when it was charged 4500 times, its capacity retention rate still reached 66.62%, as shown in the above table.

As comparative example 2: in the case where other experimental conditions are not changed, if the length and the width of the buffer member 2 are adjusted to be 0.8 times the length and the width of the battery cell, respectively, the capacity retention ratio will obtain the experimental result shown in fig. 7C. As shown in the figure, when the battery module was charged 4500 times, the capacity retention rate was 63.86%,

as can be seen from the comparison of fig. 7A to 7C, for the battery module structure such as the unit a, when the thickness of the buffer member 2 is 0.15 times the thickness of the battery cell, and the length and the width are 0.95 times the thickness of the battery cell, the battery module can achieve the highest capacity retention rate.

Fig. 8A-8C show the test levels of pressure under different experimental conditions. Based on the same experimental conditions as in the example of fig. 7A above: the battery module adopts a small module formed by the unit A. That is, adjacent cells are separated by 1 buffer, a buffer/cell/buffer … … cell/buffer stacking approach is used, and a module is secured using a strapping/end plate. The thickness of the buffer part 2 is 0.15 times of the thickness of the battery cell, the length and the width of the buffer part are respectively 0.95 times of the thickness of the battery cell 1, the buffer part 2 is made of polypropylene foam, and the density of the buffer part 2 is 35-40 kg/m³(ii) a The hardness is 55 to 65 degrees (HC); the pore diameters are distributed within the range of 10-80 um and are intensively distributed within the range of 30-50 um. At this time, referring to fig. 8A, it can be seen that the pressure and the number of times of charging are substantially linear, and become larger as the number of times of charging increases. When it was charged 4500 times, its pressure reached 286KG/F, as shown in the above table.

As comparative example 1, if the thickness of the cushioning member 2 is adjusted to 0.1 times the thickness of the battery cell 1 without changing other experimental conditions, the relationship between the pressing force and the number of times of charging is shown in fig. 8B. As shown in the figure, the pressure and the number of times of charging are substantially linear until about 3400 times, and become gradually larger as the number of times of charging increases. However, when the number of times exceeds 3500, the pressure rapidly increases. When it was charged 4500 times, its pressure was 1545KG/F, as in the above table.

As comparative example 2: in the case where other experimental conditions are not changed, if the length and the width of the buffer member 2 are respectively adjusted to be 0.8 times of the length and the width of the battery cell 1, the relationship between the pressing force and the number of times of charging is shown in fig. 8C. The graph is similar to that of fig. 8A, but the pressure value is lower than the pressure value shown in fig. 8A for the same number of charges. For example, when the battery module is charged 4500 times, the pressure value is 232 KG/F.

As can be seen from the comparison of fig. 8A to 8C, for the battery module structure of the unit a, when the thickness of the buffer member 2 is 0.15 times the thickness of the battery cell, and the length and the width are 0.95 times the thickness of the battery cell, respectively, the pressure can be kept optimal when the battery module is charged 4500 times.

More specifically, the thickness of the buffer (foam) in the embodiment shown in fig. 8B is small, and when the number of cycles is large, the buffer space provided by the buffer is small, which causes the cell to swell greatly, which may result in the shortened battery life; the buffer part shown in fig. 8C has a small area, and does not cover the area of the battery cell enough, so that the buffer space provided is small, the battery cell expands greatly, and the service life of the battery is shortened.

As used in this application, spatially relative terms such as "below," "lower," "above," "upper," "lower," "left," "right," and the like may be used herein for ease of description to describe one component or feature's relationship to another component or feature as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used in this application interpreted accordingly. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present.

In the present application, the term "about" generally means within ± 10%, ± 5%, ± 1% or ± 0.5% of a given value or range. Ranges may be expressed herein as from one end point to another end point or between two end points. Unless otherwise specified, all ranges disclosed herein are inclusive of the endpoints.

Features of several embodiments and detailed aspects of the present application are summarized above. Numerous and varied changes, substitutions and alterations can be made by those skilled in the art without departing from the spirit and scope of this application, and all such equivalent constructions are intended to be within the scope of this application.

Claims

1. The utility model provides a battery module which characterized in that, battery module includes:

a plurality of battery cells (1) which are sequentially stacked;

at least one buffer (2) disposed between at least two of the plurality of cells (1), the buffer (2) being elastically deformable such that when the cells (1) expand, the buffer (2) provides an expansion space, and when the cells (1) contract, the buffer (2) recovers;

wherein at least one of a thickness, a length and a width of the buffer (2) is associated with a corresponding one of a thickness, a length or a width of the cell (1),

when the buffer member (2) deforms in the range of 0% to 85% of strain range, 0 to 1Mpa of acting force is provided.

2. The battery module according to claim 1, wherein: at least one of the thickness, the length and the width of the buffer piece (2) is associated with the corresponding one of the thickness, the length and the width of the battery cell (1), and when the buffer piece (2) deforms in the range of 10% to 70% of the strain range, the acting force of 0 to 0.5Mpa is provided.

3. The battery module according to claim 1, wherein: at least one of the thickness, the length and the width of the buffer (2) is associated with a corresponding one of the thickness, the length or the width of the battery cell (1), and the buffer provides an acting force of 0.5 to 0.8MPa when deformed within a strain range of 70 to 80 percent.

4. The battery module according to claim 1, wherein: the battery cell structure is characterized in that a first number of the battery cells (1) and a second number of the battery cells (1) are respectively arranged on two sides of the buffer piece (2), wherein the first number is larger than or equal to the second number, the first number is N, and the thickness of the buffer piece (2) is N times (0.12-0.18) the thickness of the battery cells (1).

5. The battery module according to claim 4, wherein: the thickness of the buffer (2) is N times (0.14 to 0.16) the thickness of the battery cell (1).

6. The battery module according to claim 1, wherein: all be provided with between each adjacent electric core (1) in a plurality of electric core (1) bolster (2), the thickness of bolster (2) is 0.14 to 0.16 times of the thickness of electric core (1).

7. The battery module according to claim 6, wherein: the thickness of the buffer piece (2) is 0.15 times of that of the battery cell (1).

8. The battery module according to claim 1, wherein: electric core (1) with bolster (2) all have flat structure, the length of bolster (2) is 0.9 to 1.05 times of the length of electric core (1).

9. The battery module according to claim 8, wherein: the length of the buffer piece (2) is 0.95 to 1.0 time of the length of the battery cell (1).

10. The battery module according to claim 1, wherein: electric core (1) with bolster (2) all have flat structure, the width of bolster (2) is 0.9 to 1.05 times of the width of electric core (1).

11. The battery module according to claim 10, wherein: the width of the buffer piece (2) is 0.95 to 1.0 times of the width of the battery cell (1).