CN108695574B

CN108695574B - Battery module and power battery

Info

Publication number: CN108695574B
Application number: CN201710223855.4A
Authority: CN
Inventors: 葛增芳; 方杰; 龚骁; 刘宇; 王林峰
Original assignee: NIO Co Ltd
Current assignee: NIO Co Ltd
Priority date: 2017-04-07
Filing date: 2017-04-07
Publication date: 2022-11-08
Anticipated expiration: 2037-04-07
Also published as: WO2018184309A1; CN108695574A

Abstract

The invention provides a battery module and a power battery, wherein the battery module comprises: a plurality of battery cells arranged in a longitudinal direction, the plurality of battery cells having a housing; and an intermediate member disposed between the adjacent battery cells; wherein adjacent ones of the intermediate members are fluid-tightly engaged and surround at least a portion of a housing of a battery cell therebetween; wherein adjacent ones of the intermediate members together with the case of the battery cell therebetween define a cooling fluid flow path such that a cooling fluid passes between the intermediate members and the case of the battery cell and directly contacts the battery cell. The battery module and the power battery provided by the invention have the advantages of high cooling efficiency, light weight, safety, stability, strong expandability and the like.

Description

Battery module and power battery

Technical Field

The invention relates to the technical field of power batteries, in particular to a battery module with a battery unit directly contacted with cooling fluid and a power battery with the battery module.

Background

In the application of the current power battery, especially in the field of new energy electric automobiles, the power battery is required to have higher specific energy, the high specific energy is smaller in volume and weight, and a power system can provide higher energy. Meanwhile, the power battery is also required to have higher safety factor and longer service life. For a high energy density power battery, certain heat can be generated during operation, and if the heat cannot be timely dissipated, the service life and safety performance of the power battery are greatly damaged. The design of a battery power cooling system which ensures that the battery is maintained at a proper temperature and has light weight is urgently needed to meet the requirements of high energy density and light weight of the whole power system.

In the design of the current power battery cooling scheme, an air cooling mode cooling system is large in size and low in cooling efficiency, and the requirements of temperature rise and temperature difference of a battery under the condition of high-rate charge and discharge are difficult to meet; the liquid cooling mode has high efficiency, but the cooling plate/cooling pipe mode is adopted at present, a cooling fluid body is in indirect contact with the battery, larger thermal resistance exists between the battery and a refrigerant, so that the cooling efficiency cannot reach the best, meanwhile, the risk that the cooling plate/cooling pipe is broken to cause the outflow of the cooling fluid is generated, and the safety coefficient of the power battery is reduced.

The technical scheme of liquid cooling and direct cooling of the battery also exists in the prior art, wherein the battery module is directly placed in the insulating flame-retardant liquid, the battery can be directly cooled, but other components of the battery system are immersed in the liquid, so that the safety risks of corrosion of the liquid on other key components and the like are brought, and meanwhile, the scheme is more in cooling fluid, the specific energy of the power battery is reduced to a certain extent, and the cost is increased.

Disclosure of Invention

The present invention is directed to improve cooling efficiency by allowing a cooling fluid in a battery module to directly contact a battery cell, while minimizing a temperature difference of a battery in a whole battery system.

The purpose of the present invention is to improve the energy ratio of a battery module.

The invention aims to improve the expandability of the battery module by adopting a modular design.

The invention aims to avoid the direct contact of cooling fluid with other key components of the power battery so as to avoid the damage of corrosion and the like to the power battery and improve the safety of the power battery.

It is also an object of the present invention to solve or at least alleviate other problems existing in the prior art.

To achieve the object of the present invention, according to an aspect of the present invention, there is provided a battery module including:

a plurality of battery cells arranged in a longitudinal direction, the plurality of battery cells having a case; and

an intermediate member disposed between adjacent battery cells;

wherein adjacent ones of the intermediate members are fluid-tightly engaged and surround at least a portion of a housing of a battery cell therebetween;

wherein adjacent ones of the intermediate members together with the case of the battery cell therebetween define a cooling fluid flow path such that a cooling fluid passes between the intermediate members and the case of the battery cell and directly contacts the battery cell.

Optionally, in the above battery module, the intermediate member includes first and second opposite sides, one of the first and second sides of the intermediate member has a flow stopper that prevents fluid from passing in the longitudinal direction, and the other of the first and second sides of the intermediate member has a longitudinal flow path that allows fluid to pass in the longitudinal direction.

Alternatively, in the above battery module, in the battery module, the adjacent intermediate members are arranged such that the flow stoppers of the adjacent intermediate members are on opposite sides of the battery module.

Alternatively, in the above battery module, the plurality of battery cells are substantially cubic in outer shape, and the adjacent intermediate members surround five surfaces of the battery cells except for the electrode sides.

Alternatively, in the above battery module, the intermediate member has a third side opposite to the electrode side of the battery cell, and the intermediate member has a lateral flow path in the lateral direction on the third side.

Optionally, in the above battery module, the intermediate member has a flow guide in the middle to define a middle flow path between the adjacent battery cells.

Alternatively, in the above battery module, the adjacent intermediate members are provided with a stopper portion at the joint so that the adjacent intermediate members are aligned.

Optionally, in the above battery module, the battery module further includes end members at both ends, the end members having a fluid inlet or a fluid outlet.

Optionally, in the above battery module, the battery module further includes a mounting part outside the end member, wherein the mounting part, the end member and each intermediate member have a plurality of mounting holes corresponding in position, and a plurality of bolts pass through the corresponding plurality of holes to assemble the mounting part, the end member and each intermediate member together.

Optionally, in the battery module, a sealing member is provided at a joint of the adjacent intermediate member and the battery cell.

Optionally, in the above battery module, the cooling fluid is a flame retardant insulating fluid.

The invention also provides a power battery which comprises the battery module according to various embodiments of the invention.

The battery module and the power battery provided by the invention have the advantages of high cooling efficiency, high energy density, light weight, safety, stability, strong expandability and the like.

Drawings

The disclosure of the present invention will become more readily understood with reference to the accompanying drawings. As is readily understood by those skilled in the art: these drawings are for illustrative purposes only and are not intended to constitute a limitation on the scope of the present invention. Moreover, in the drawings, like numerals are used to indicate like parts, and in which:

fig. 1 illustrates a perspective view of a battery module according to an embodiment of the present invention when assembled;

fig. 2 is a perspective view illustrating an exploded battery module according to an embodiment of the present invention;

FIGS. 3 and 4 respectively show different angled perspective views of an intermediate member according to an embodiment of the invention;

FIG. 5 shows a perspective view of an end member according to an embodiment of the invention;

FIG. 6 illustrates a perspective view of a mounting member according to an embodiment of the present invention; and

fig. 7 shows a fluid flow path diagram of the battery module according to the embodiment of the present invention.

The specific implementation mode is as follows:

it is easily understood that according to the technical solution of the present invention, a person skilled in the art can propose various alternative structures and implementation ways without changing the spirit of the present invention. Therefore, the following detailed description and the accompanying drawings are merely illustrative of the technical aspects of the present invention, and should not be construed as all of the present invention or as limitations or limitations on the technical aspects of the present invention.

The terms of orientation of up, down, left, right, front, back, top, bottom, and the like referred to or may be referred to in this specification are defined relative to the configuration shown in the drawings, and are relative terms, and thus may be changed correspondingly according to the position and the use state of the device. Therefore, these and other directional terms should not be construed as limiting terms.

It should be understood that in the description and drawings of the present invention, the x direction in fig. 1 is referred to as the longitudinal direction, the y direction is referred to as the transverse direction, the z direction is referred to as the vertical direction, and the corresponding directions in fig. 1 are expressed by the expressions "transverse direction", "vertical direction" and "longitudinal direction" in other views.

Referring first to fig. 1 and 2, there are shown schematic views of a battery module according to an embodiment of the present invention in an assembled and to-be-assembled state. The battery module 10 includes a plurality of battery cells 1 arranged in the longitudinal direction with an intermediate member 2 disposed between each pair of adjacent battery cells 1, such as between the battery cells 1 and 1' in fig. 2. In the embodiment shown in fig. 1, the plurality of battery cells 1 includes 12 battery cells 1 and 11 intermediate members 2. In an alternative embodiment, n +1 battery cells 1 and n intermediate members 2 may be included. Further, end members 3 are disposed at both ends of the plurality of battery cells 1, and mounting parts 4 are disposed outside the end members 3.

In the illustrated embodiment, the plurality of battery cells 1 have a housing or casing in the shape of a cube. It has six faces including laterally opposite first and second sides, vertically opposite top and bottom sides, and longitudinally opposite front and rear sides. In the illustrated embodiment, the top side of the case of the battery unit 1 is an electrode side having positive and negative electrode terminals 11 and 12, and hereinafter, the bottom side opposite to the electrode side is also referred to as a third side. It should be understood that although the housing of the battery cells is shown in a cubic shape in all embodiments, in alternative embodiments, the plurality of battery cells may be other shapes. In the vicinity of the top side or electrode side of the battery cell, the intermediate member 2 is engaged with the case of the battery cell 1. A seal member, such as a gasket, is provided at the joint between the intermediate member 2 and the battery cell 1 so as to be impermeable to fluid. At other sides than the top side or the electrode side, including the first side, the second side, and the bottom side, adjacent intermediate members 2 are joined to each other so as to surround a portion of the case of the battery cell 1. A seal, such as a gasket, is also provided at the joint between the adjacent intermediate members 2 to make it impervious to fluid. The case of the battery cell 1 and the intermediate member 2 together define a cooling fluid flow path after the battery module is assembled, so that the cooling fluid can directly contact the case of the battery cell 1 while the electrodes of the battery cell can be exposed. Although the electrodes 11,12 of the battery cell 1 are exposed, the cooling fluid is confined in the cooling fluid flow path and does not leak due to the sealing engagement between the intermediate member and the battery cell and the sealing engagement between the adjacent intermediate members. In some embodiments, the cooling fluid directly contacts all five sides of the battery cell, including the front side, the back side, the first side, the second side, and the bottom side, except for the electrode side, and the cooling of the battery cell may be more efficiently performed by directly contacting the cooling fluid with the sides of the battery cell. In some embodiments, as shown in fig. 2, each of the intermediate member 2, end member 3 and mounting component 4 is provided with a plurality of mounting holes at a plurality of corresponding locations, and a plurality of bolts 51 are passed through the plurality of mounting holes on the corresponding components and received by nuts 52 on opposite sides, thereby holding the components and the battery cells between the intermediate members together. In alternative embodiments, the components of the battery module may also be held together by other means.

With continued reference to fig. 3 and 4, one embodiment of intermediate member 2 will be described in detail. The intermediate member 2 has a generally rectangular frame shape with a first side 22, a second side 23, a top or electrode side 21 and a bottom or third side 24. Since the middle section of the top side 21 of the intermediate member 2 is used for bonding with the electrode sides of the battery cells on both sides, it has a reduced width. The front and rear sides of each intermediate member 2 define a cell receptacle with the adjacent intermediate member, respectively, or in other words, the front and rear sides of the intermediate member 2 define half of the cell receptacle, respectively. Since the front and rear sides of the intermediate member 2 are substantially symmetrical in structure in the present embodiment, the front side of the intermediate member 2, which is easy to observe, is mainly described below.

In some embodiments, the intermediate member 2 has a plurality of flow guides at a third or bottom side 24 opposite the electrode side. In this embodiment, the flow guide is formed as a plurality of ribs, including a central rib 242 and an outer rib 241, which together define a transverse flow path in the transverse direction. The cooling fluid may pass from the bottom side of the battery cell along a lateral flow path, such as in the direction indicated by arrow a, and directly contact and exchange heat with the bottom side of the battery cell. In alternative embodiments, the flow guides on the bottom side may define lateral flow paths different from those shown, e.g., the flow paths defined by the flow guides may be in any direction and may be turned, e.g., a labyrinth flow path may be formed on the bottom side of the intermediate member to enhance contact of the cooling fluid with the bottom side of the battery cell.

In some embodiments, the middle portion of the intermediate member has a flow guide, such as a plurality of ribs 26. The plurality of ribs 26 define a plurality of lateral flow paths therebetween in the lateral direction. The cooling fluid may pass between the adjacent two battery cells in the direction of the lateral flow path as indicated by the arrow B, and directly contact and exchange heat with the front and rear sides of the adjacent two battery cells. It should be understood that although in the illustrated embodiment the intermediate member's middle flow guide is formed as flow ribs extending parallel to the horizontal direction of the top and

bottom sides

21, 24 to define transverse flow paths, in alternative embodiments the intermediate member's middle flow guide may have other forms, for example may comprise flow paths in the transverse, vertical, longitudinal, diagonal or labyrinth manner, such that the cooling fluid can more fully contact the front and rear sides of the adjacent corresponding battery cells.

In some embodiments, one or both of the first side 22 and the second side 23 of the intermediate member 2 may be provided with a flow guide, e.g., a plurality of

ribs

221, 231. The plurality of ribs of the first side 22 and the second side 23 of the intermediate member 2 define therebetween a plurality of longitudinal flow paths in the longitudinal direction. The cooling fluid may pass from one or both sides of the battery cell in the direction of the longitudinal flow path as indicated by arrow C and may be in direct contact with and exchange heat with the first and/or second side of the battery cell. In alternative embodiments, the flow guides of the first and

second sides

22, 23 of the intermediate member may define non-longitudinal flow paths, e.g., the flow paths defined by the flow guides may be in any direction and may be diverted, e.g., a labyrinth flow path may be formed at the first and/or second side of the intermediate member to enhance contact of the cooling fluid with the first and/or second side of the battery cell.

In some embodiments, one of the first and

second sides

22, 23 of the intermediate member is provided with a flow stop, as shown in fig. 4, a flow stop in the form of a stop rib 222 being provided on the inside of the first side 22. The presence of the stop rib 222 prevents the cooling fluid from passing completely or largely through the first side 22, whereby the cooling fluid is forced to bypass in the direction of arrows B and C. In some embodiments, in the battery module, the adjacent intermediate members are arranged such that the flow stoppers of the adjacent intermediate members are on opposite sides of the battery module, in other words, the stopper ribs 222 of the adjacent intermediate members may be provided on the first and second sides at intervals, thereby allowing the cooling fluid in the battery module to pass through the cooling liquid flow path substantially in the "S" shaped line as indicated by the arrows in fig. 7. In alternative embodiments, the configuration of the flow guides and/or flow stoppers on each side and middle of each intermediate member in the battery module may be arbitrarily selected so that the cooling fluid in the battery module passes along other lines, such as "U" or "Z" lines.

In some embodiments, the intermediate members 2 have a plurality of mounting holes 251,252 disposed along their periphery, wherein the mounting holes 252 are formed as protrusions to engage with corresponding notches when engaged with adjacent intermediate members 2 to act as a stop so that each intermediate member 2 can be aligned. In alternative embodiments, adjacent intermediate members 2 may have other forms of stoppers at the joints to limit the positional relationship therebetween. In some embodiments, the constriction of the top side 21 of the intermediate member 2, the

ribs

241, 242 of the bottom side 24, the first side rib 221 and the second side rib 231, and the middle rib 26, among others, cooperate to restrain the battery cell.

Referring to fig. 5, one embodiment of the end member 3 is shown. The end member 3 comprises a top side 31, a bottom side 34, a first side 32 and a second side 33. The end members 3 may have a similar construction to half of the intermediate member 2 and have end walls 35. The end wall 35 is spaced a distance from the front or rear side of the cell when the cell is engaged with the end member 3 to form an inflow or outflow zone. Furthermore, similar flow guides are provided on the bottom side 34, the first side 32 and the second side 33 of the end piece 3. The end members 3 together with the adjacent intermediate members 2 and the battery cells therebetween also define a fluid flow path. In addition, there may be a cooling fluid inlet or outlet 36 on the end wall 37. The end member 3 may have a mounting hole 35 and a stopper portion around the circumference thereof corresponding to the position of the intermediate member 2.

Referring to fig. 6, one embodiment of the mounting member 4 is shown. The mounting part 4 may be formed integrally with the end member 3 or may be formed separately from the end member 3 as shown in the present embodiment. The mounting part 4 has a body 42 in the form of a flat plate, a mounting hole 45 around the body 42 and an opening 46 through which a fluid conduit can pass. The mounting members further include mounting screw holes 41, and the entire battery module can be fixed to the power battery by means of the mounting screw holes 41 of the both-side mounting members 4. In some embodiments, the intermediate member 2 and the end members 3 may be made of a plastic material and the mounting component 4 may be made of metal.

Referring to FIG. 7, one embodiment of a cooling fluid flow path is shown. The cooling fluid enters the intake zone 8 of the cooling flow path from the cooling fluid inlet 71. Thereafter, a portion of the cooling fluid flows around the battery cells in the directions indicated by arrows B and C, and another portion of the cooling fluid intermittently flows through the third sides of the respective battery cells in the direction indicated by arrow a. The cooling fluid eventually converges to the outflow region 9 and exits through the cooling fluid outlet 72. The cooling fluid flow path can adopt flame-retardant insulating fluid, so that the safety of the battery cannot be affected even if the cooling fluid flow path leaks, the cooling fluid has a flame-retardant effect, and can serve as a flame retardant when the battery is strongly extruded or punctured and burns, so as to prevent the damaged battery from affecting other surrounding batteries, prevent the phenomenon from expanding and delaying the accident deterioration time to a certain extent, strive for more sufficient rescue time, and greatly improve the safety of a battery power system.

The foregoing description of the specific embodiments has been presented only to illustrate the principles of the invention more clearly, and in which various features are shown or described in detail to facilitate an understanding of the principles of the invention. Various modifications or changes to the invention will be readily apparent to those skilled in the art without departing from the scope of the invention. It is to be understood that such modifications and variations are intended to be included within the scope of the present invention.

Claims

1. A battery module, comprising:

a plurality of battery cells arranged in a longitudinal direction, the plurality of battery cells having a housing; and

a plurality of intermediate members disposed between adjacent battery cells;

wherein the adjacent intermediate members together with the case of the battery cell therebetween define a cooling fluid flow path such that a cooling fluid passes between the intermediate members and the case of the battery cell and directly contacts the battery cell, wherein the plurality of battery cells have a cubic outer shape, the adjacent intermediate members surround five surfaces of the battery cell except for an electrode side, and the cooling fluid directly contacts all five side surfaces of the battery cell except for the electrode side.

2. The battery module of claim 1, wherein the intermediate member includes opposing first and second sides, one of the first and second sides of the intermediate member having a flow stop that prevents fluid from passing longitudinally therethrough, the other of the first and second sides of the intermediate member having a longitudinal flow path that allows fluid to pass longitudinally therethrough.

3. The battery module according to claim 2, wherein in the battery module, the adjacent intermediate members are arranged such that the flow stoppers of the adjacent intermediate members are on opposite sides of the battery module.

4. The battery module according to claim 1, characterized in that the intermediate member has a third side opposite to the electrode side of the battery cell, the intermediate member having a lateral flow path in the lateral direction on the third side.

5. The battery module according to claim 1, wherein the intermediate member has a flow guide in the middle to define a middle flow path between adjacent battery cells.

6. The battery module according to claim 1, wherein adjacent intermediate members are provided at junctions with stopper portions such that the adjacent intermediate members are aligned.

7. The battery module according to claim 1, further comprising end members at both ends, the end members having a fluid inlet or a fluid outlet.

8. The battery module according to claim 1, further comprising a mounting part outside the end members, wherein the mounting part, the end members, and each of the intermediate members have a plurality of mounting holes corresponding in position, and a plurality of bolts pass through the corresponding plurality of holes to assemble the mounting part, the end members, and each of the intermediate members together.

9. The battery module according to claim 1, wherein a sealing member is provided at the junction of the adjacent intermediate members and the battery cell.

10. The battery module according to claim 1, wherein the cooling fluid is a flame retardant insulating fluid.

11. A power battery, characterized in that the power battery comprises the battery module according to any one of claims 1-10.