Battery module and battery pack

Abstract

The utility model discloses a battery module and a battery pack, the battery module comprises at least two battery cells arranged along the length direction of the battery module, a heat insulation part is arranged between two opposite large surfaces of two adjacent battery cells, the heat insulation part is provided with a closed liquid storage cavity, a cooling medium is stored in the liquid storage cavity, and the liquid storage cavity is communicated with the battery module. The melting point of the heat insulation part is higher than the normal working temperature of the battery cell and lower than the thermal runaway temperature of the battery cell. The battery module has relatively good thermal runaway protection capability and relatively high safety.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery module and a battery pack. BACKGROUND

[0002] With the rapid development of electric vehicles, energy storage power stations and other fields, lithium ion batteries are increasingly widely used. Lithium ion batteries are prone to thermal runaway under conditions such as overcharging, overdischarging, short circuit or high temperature, which may cause fire or even explosion, and there is a serious safety hazard.

[0003] In the related art, in order to prevent the spread of thermal runaway of a single cell to adjacent cells, in some solutions, an aerogel type thermal insulation pad is provided as a thermal insulation material between adjacent cells, but since the aerogel is a pure thermal insulation material, it cannot actively cool down, and the protection effect is limited. In some other solutions, a spraying device is provided on the top of the explosion-proof valve of the cell, and the spraying device is directly opposite or partially opposite to the explosion-proof valve. When the cell is in thermal runaway, the spraying device is opened by active opening or passive melting, and the cooling medium in the spraying device is sprayed to the explosion-proof valve of the runaway cell to cool down the runaway cell and the adjacent cells, so as to suppress the spread of heat. However, the sprayed cooling medium can only contact the top cover of the cell, and the top cover area of the cell is small, which cannot effectively cool down the cell, and the protection effect is also limited.

[0004] Therefore, how to improve the thermal runaway protection capability of the battery pack to effectively improve the safety of the battery pack has become a technical problem to be solved by those skilled in the art. Utility model content

[0005] The purpose of the present application is to provide a battery module and a battery pack, which have good thermal runaway protection capability and high safety.

[0006] To solve the above technical problems, the present application provides a battery module, which comprises at least two cells arranged along the length direction of the battery module, and a thermal insulation component is arranged between the two opposite large surfaces of two adjacent cells. The thermal insulation component has a closed liquid storage cavity, and a cooling medium is stored in the liquid storage cavity. The melting point of the thermal insulation component is higher than the normal working temperature of the cell and lower than the thermal runaway temperature of the cell.

[0007] In an implementable solution, the thermal insulation component comprises two first peripheral wall portions arranged along the length direction, and a plurality of partition ribs arranged along the width direction of the battery module are connected between the two first peripheral wall portions. The plurality of partition ribs separate the liquid storage cavity into a plurality of liquid storage sub-cavities.

[0008] In an implementable solution, the partition ribs are arranged obliquely relative to the first peripheral wall portions, and the oblique directions of the partition ribs are consistent.

[0009] In an implementation, the included angle θ between the partition rib and the first peripheral wall part is 20°-80°.

[0010] In an implementation, two adjacent partition ribs have opposite surfaces, and the distance between the two adjacent partition ribs in the normal direction of the surfaces is 3mm-20mm.

[0011] In an implementation, each of the liquid storage sub-chambers is connected to each other.

[0012] In an implementation, the thermal insulation part includes two end covers arranged along the height direction of the battery module, the end covers are connected to the end of the first peripheral wall part in the height direction, and each of the one end of the partition rib and the one end cover at the same end and the other end of the partition rib and the other end cover at the same end has a set distance.

[0013] In an implementation, the peripheral wall part of the thermal insulation part is a plate structure, the thickness t1 of the peripheral wall part is 0.3mm-1mm; and / or, the partition rib arranged in the thermal insulation part is a plate structure, and the thickness t2 of the partition rib is 0.3mm-1mm.

[0014] In an implementation, the thickness t3 of the end cover of the thermal insulation part is 0.5mm-2mm.

[0015] In an implementation, the volume of the cooling medium stored in the liquid storage chamber is 30%-60% of the volume of the liquid storage chamber.

[0016] In an implementation, the thermal insulation part is a thermal insulation part made of thermoplastic non-metallic material.

[0017] The embodiments of the present application also provide a battery pack including a battery box, and the battery box is installed with the battery module as described in any one of the above.

[0018] The battery module provided by the embodiment of the application is used for constituting a battery pack, and the battery pack can be applied to an electric vehicle or used in an energy storage power station. The battery module is provided with a heat insulation component between large surfaces of two adjacent battery cells, and the heat insulation component has a liquid storage cavity for storing a cooling medium. When a battery cell of the battery module has thermal runaway, the heat insulation component is in contact with the large surface of the battery cell. Since the melting point of the heat insulation component is lower than the thermal runaway temperature of the battery cell, the heat insulation component can be melted and damaged in a short time to form a leakage opening, and the cooling medium in the liquid storage cavity can flow out and be released to the large surface of the battery cell. Through heat absorption of the cooling medium, active cooling can be realized. The contact area between the cooling medium and the large surface of the battery cell is large, and the battery cell having thermal runaway and the battery cell adjacent to the battery cell having thermal runaway can be effectively cooled, so that the occurrence of thermal spread can be effectively inhibited, and the use safety of the battery module is improved.

[0019] In addition, the heat insulation component arranged between the large surfaces of the two adjacent battery cells can also resist the expansion cycle of the battery cell. Specifically, the volume of the battery cell changes during the expansion cycle, and the arrangement of the heat insulation component can provide pre-tightening force for the battery cell to support the expansion cycle of the battery cell. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A structural diagram of a battery module in an embodiment provided by the application is shown in FIG. 1.

[0021] Figure 2 An exploded view of the battery module in an embodiment provided by the application is shown in FIG. 2.

[0022] Figure 3 A front view of a battery cell in an embodiment provided by the application is shown in FIG. 3. Figure 2

[0023] A front view of a heat insulation component in an embodiment provided by the application is shown in FIG. 4. Figure 4 Figure 2 A top view of the heat insulation component is shown in FIG. 5.

[0024] Figure 5 Figure 4 An exploded view of the heat insulation component in an embodiment provided by the application is shown in FIG. 6.

[0025] Figure 6 A structural diagram of a cavity body in an embodiment provided by the application is shown in FIG. 7.

[0026] Figure 7 A partial structural diagram of the cavity body is shown in FIG. 8. Figure 6

[0027] A sectional view of the cavity body in an embodiment provided by the application is shown in FIG. 9. Figure 8 Figure 7 A sectional view of the cavity body in an embodiment provided by the application is shown in FIG. 10.

[0028] Figure 9 A sectional view of the cavity body in an embodiment provided by the application is shown in FIG. 11. Figure 7

[0029] Explanation of reference signs: ​​​​

[0030] Battery cell 100, large face 110, pole 120;

[0031] Thermal insulation component 200, cavity body 210, peripheral wall part 211, first peripheral wall part 2111, second peripheral wall part 2112, partition rib 212, end cover 220, liquid storage cavity 230, liquid storage sub-cavity 231;

[0032] Electrical connecting sheet 300;

[0033] First direction x, second direction y, third direction z. DETAILED DESCRIPTION

[0034] In order to make the person skilled in the art better understand the scheme of the present application, the present application will be further described in detail below in combination with the drawings and specific embodiments.

[0035] The ordinal numbers such as first, second, etc. used herein are used to distinguish different components with the same name, and do not represent a specific order or primary and secondary relationship, etc.

[0036] Please refer to Figure 1 and Figure 2 , Figure 1 is a structural diagram of a battery module provided in an embodiment of the present application, Figure 2 is an exploded view of a battery module provided in an embodiment of the present application.

[0037] For the convenience of understanding and description, three directions are constructed in the present application, which are first direction x, second direction y and third direction y. The first direction x is the length direction of the battery module, the second direction y is the width direction of the battery module, and the third direction z is the height direction of the battery module. The length direction, the width direction and the height direction involved in the present application are all based on the battery module. The top (upper) or the bottom (lower) involved in the present application refers to the top or the bottom in the third direction z.

[0038] In the present embodiment, the battery module includes one or more cell groups, each cell group includes two or more battery cells 100, and each battery cell 100 in each cell group is arranged along the first direction x. When the battery module is provided with two or more cell groups, each cell group is arranged along the second direction y.

[0039] In the first direction x, the thermal insulation component 200 is arranged between the facing large faces 110 of the adjacent two battery cells 100, and the thermal insulation component 200 has a closed liquid storage cavity 230 (marked in Figure 6 ), which stores a cooling medium, and the melting point of the thermal insulation component 200 is higher than the normal working temperature of the battery cell 100 and lower than the thermal runaway temperature of the battery cell 100.

[0040] Please refer to Figure 3 , Figure 3A front view of an electric cell 100 is shown. In combination Figure 1 and Figure 2 The electric cell 100 is roughly in a cuboid structure, having six surfaces, among which two surfaces are opposite to each other in a first direction x, and the area of the two surfaces is greater than that of the remaining four surfaces, which are referred to as large surfaces 110 of the electric cell 100.

[0041] The top surface of the electric cell 100 is provided with a pole 120, and the battery module further includes an electric connecting sheet 300, and the electric cells 100 of the battery module can be connected in series or in parallel through the electric connecting sheet 300.

[0042] With the above scheme, when a certain electric cell 100 of the battery module is in thermal runaway, the heat insulation component 200 is in contact with the large surface 110 of the electric cell 100, and since the melting point of the heat insulation component 200 is lower than the thermal runaway temperature of the electric cell 100, the heat insulation component 200 can be melted and damaged in a short time to form a leakage opening, and the cooling medium in the liquid storage cavity 230 can flow out and be released to the large surface 110 of the electric cell 100, and the heat absorption of the cooling medium can achieve active cooling, effectively cooling the electric cell 100 in thermal runaway and the electric cell 100 adjacent to it, thereby effectively inhibiting the occurrence of heat spread and improving the use safety of the battery module. In addition, the heat insulation component 200 arranged between the large surfaces 110 of the two adjacent electric cells 100 can also play a role in resisting the swelling cycle of the electric cell 100. Specifically, the volume of the electric cell 100 changes during the swelling cycle, and the arrangement of the heat insulation component 200 can provide a pre-tightening force for the electric cell 100 to support the swelling cycle of the electric cell 100.

[0043] The normal working temperature of the electric cell 100 and the thermal runaway temperature of the electric cell 100 can be determined by experiments or simulations in combination with the actual application scenario of the battery module, and no specific temperature value is limited here.

[0044] For example, the melting point of the heat insulation component 200 can be designed to be not higher than 400℃.

[0045] Please refer to Figures 4 to 6 , Figure 4 for Figure 2 a front view of the heat insulation component, Figure 5 for Figure 4 a top view of the heat insulation component, Figure 6 for an exploded view of the heat insulation component in an embodiment provided in the present application.

[0046] In some embodiments, the heat insulation component 200 comprises a cavity body 210 and two end covers 220, wherein the cavity body 210 is open at the top and bottom ends in the third direction z, and the two end covers 220 are used to seal the top and bottom openings of the cavity body 210, respectively. The cavity body 210 comprises a circumferentially closed peripheral wall portion 211, and the end covers 220 are connected to the ends of the peripheral wall portion 211 in the third direction z. The peripheral wall portion 211 and the two end covers 220 enclose a closed liquid storage cavity 230. In this way, the heat insulation component 200 is provided as a split cavity body 210 and end covers 220, which facilitates the processing of the heat insulation component 200.

[0047] In other embodiments, the heat insulation component 200 can comprise a box-shaped body that is open only at the top or bottom, and a cover plate is used to seal the opening of the box-shaped body. In other embodiments, the cavity body 210 and the end covers 220 of the heat insulation component 200 can also be integrally formed.

[0048] In specific implementations, the same material can be used for the various components of the heat insulation component 200, and the material of the cavity body 210 and the end covers 220 can be the same.

[0049] In actual applications, the end covers 220 can be connected to the cavity body 210 by welding or bonding to ensure good sealing of the liquid storage cavity 230.

[0050] The material of the heat insulation component 200 can be a thermoplastic non-metallic material. It has good mechanical properties, heat resistance, and flame retardancy.

[0051] For example, the material of the heat insulation component 200 can be nylon 66 (PA66, also known as polyhexamethylene adipamide), or polyphthalamide (PPA), or polyphenylene oxide (PPO), etc.

[0052] In actual applications, the melting point of the cavity body 210 and the end covers 220 of the heat insulation component 200 can be lower than the thermal runaway temperature of the battery cell 100, and the structure inside the liquid storage cavity 230 of the heat insulation component 200, such as the partition 212 mentioned later, can not be limited. As long as the heat insulation component 200 can melt and release the cooling medium in the liquid storage cavity 230 to the large surface 110 of the battery cell 100 when the battery cell 100 is in thermal runaway.

[0053] For reference Figures 7 to 9 , Figure 7 To Figure 6 the structure of the cavity body, Figure 8 is Figure 7 a partial structure diagram, Figure 9 is Figure 7 an A-A cross-sectional view.

[0054] In some embodiments, the thermal insulation component 200 includes two first peripheral wall portions 2111 arranged along a first direction x, and a plurality of partition ribs 212 arranged along a second direction y are connected between the two first peripheral wall portions 2111, and a liquid storage sub-cavity 231 is formed between adjacent two partition ribs 212, and the liquid storage cavity 230 includes the liquid storage sub-cavities 231, in other words, the plurality of partition ribs 212 divide the liquid storage cavity 230 into a plurality of liquid storage sub-cavities 231. The partition ribs 212 extend along a third direction z. In this way, the thermal insulation component 200 has better rigidity, which is conducive to meeting the support function requirements required by the expansion force of the battery cell 100.

[0055] After the thermal insulation component 200 is arranged between the two battery cells 100, the first peripheral wall portion 2111 is in contact with the large face 110 of the battery cell 100. It can be understood that the first peripheral wall portion 2111 is parallel to the large face 110 of the battery cell 100, in other words, the first peripheral wall portion 2111 is parallel to the plane constructed by the second direction y and the third direction z.

[0056] The peripheral wall portion 211 of the aforementioned cavity body 210 includes two first peripheral wall portions 2111, and the peripheral wall portion 211 further includes two second peripheral wall portions 2112, which are used to connect the same ends of the two first peripheral wall portions 2111 in the second direction y, so as to close the peripheral wall portion 211 in the circumferential direction.

[0057] The cavity body 210 can include the partition rib 212, which can be integrally formed with the peripheral wall portion 211, and the cavity body 210 has a structure similar to that of a harmonica.

[0058] In specific implementations, as shown in Figure 7 and Figure 8 , the second peripheral wall portion 2112 can have an arc-shaped wall structure, and the size of the thermal insulation component 200 in the first direction x is relatively small. By configuring the second peripheral wall portion 2112 as an arc-shaped wall structure, stress concentration can be avoided at the connection between the two first peripheral wall portions 2111 of the thermal insulation component 200, which is conducive to improving the structural performance of the thermal insulation component 200.

[0059] In specific implementations, as shown in Figure 7 and Figure 8 , the partition rib 212 is arranged obliquely relative to the first peripheral wall portion 2111, and the oblique directions of the partition ribs 212 are consistent. In this way, the rigidity of the thermal insulation component 200 can be reduced, so as to prevent the rigidity of the thermal insulation component 200 from exceeding the upper limit required by the expansion force of the battery cell 100, in other words, the thermal insulation component 200 can have a certain deformation ability in the first direction x, and can resist the expansion force of the battery cell 100.

[0060] The partition rib 212 is arranged obliquely relative to the first peripheral wall portion 2111, and an included angle θ is formed between the partition rib 212 and the first peripheral wall portion 2111, as shown in Figure 8As indicated. If the included angle θ is too small, the stiffness of the heat insulation component 200 may be lower than the support required by the expansion force of the battery cell 100. If the included angle θ is too large, the stiffness of the heat insulation component 200 may exceed the upper limit of the expansion force requirement of the battery cell 100, which will have a negative impact on the cycle life of the battery cell 100. Therefore, in actual settings, the included angle θ between the partition 212 and the first peripheral wall 2111 is set to 20°~80°. For example, the included angle θ can be 30°, 35°, 40°, 45°, 50°, 60°, 75°, etc. In practical applications, the included angle θ between the partition 212 and the first peripheral wall 2111 can be determined through experiments or simulations.

[0061] In practical applications, the inclination angles of each rib 212 of the heat insulation component 200 are also consistent, which facilitates processing and also contributes to the stability of the structural performance of the heat insulation component 200.

[0062] In practical applications, the spacing between adjacent ribs 212 of the insulation component 200 can be set in the same way to ensure the balance of the structural performance of the insulation component 200.

[0063] In specific implementation, two adjacent ribs 212 have opposing surfaces, and in the normal direction of these surfaces, the distance d between two adjacent ribs 212 of the heat insulation component 200 is 3mm to 20mm. For example... Figure 8 As shown, the spacing between two adjacent ribs 212 affects the overall structural rigidity of the thermal insulation component 200. If the spacing d is too small, the ribs 212 will be too dense, resulting in an excessively high overall rigidity of the thermal insulation component 200, which may exceed the upper limit of the expansion force requirement of the battery cell 100. If the spacing d is too large, the ribs 212 will be too sparse, resulting in an excessively low overall rigidity of the thermal insulation component 200, which may fall below the support requirements for the expansion force of the battery cell 100. According to experimental verification, setting the spacing d between two adjacent ribs 212 between 3mm and 20mm is more suitable. In practical applications, the spacing d can also be set according to the specific application scenario requirements.

[0064] In specific implementation, such as Figure 8 As shown, the peripheral wall 211 of the cavity body 210 has a plate-like structure, and the thickness t1 of the peripheral wall 211 can be 0.3mm to 1mm to meet the requirements of process molding and protection against thermal runaway. Specifically, if the thickness t1 of the peripheral wall 211 is too small, it may not be feasible in the process; if the thickness t1 of the peripheral wall 211 is too large, the time required for the heat insulation component 200 to melt or decompose in the event of thermal runaway of the battery cell 100 will be too long, which is not conducive to the protection against thermal runaway. According to experimental verification, setting the thickness t1 of the peripheral wall 211 between 0.3mm and 1mm is more appropriate. In practical applications, the thickness t1 of the peripheral wall 211 can also be set according to the requirements of specific application scenarios.

[0065] In specific implementations, as shown in Figure 8 The partition rib 212 of the cavity body 210 is a plate structure, and the thickness t2 of the partition rib 212 can be 0.3 mm to 1 mm to meet the process forming requirement and the rigidity requirement of the thermal insulation component 200. Specifically, if the thickness t2 of the partition rib 212 is too small, it can not be realized in the process, and if the thickness t2 of the partition rib 212 is too large, the rigidity of the thermal insulation component 200 is too large, which can exceed the upper limit of the expansion force requirement of the battery cell 100, and the weight is also too large. According to the test verification, it is more appropriate to set the thickness t2 of the partition rib 212 to be between 0.3 mm and 1 mm. In actual application, the thickness t2 of the partition rib 212 can also be set according to the requirements of the specific application scene.

[0066] For example, the thickness of the end cover 220 can be 0.5 mm to 2 mm to meet the rigidity requirement of the thermal insulation component 200.

[0067] In some embodiments, the liquid storage sub-cavities 231 of the thermal insulation component 200 are in communication with each other. In this way, the liquid storage sub-cavities 231 are not completely isolated, which can ensure the uniformity of the distribution of the cooling medium and is beneficial to improve the cooling efficiency of the battery cell 100.

[0068] In specific implementations, as shown in Figure 9 The first set distance c1 is between one end of the partition rib 212 and one end cover 220 located at the same end, and the second set distance c2 is between the other end of the partition rib 212 and the other end cover 220 located at the same end. In this way, no matter the orientation of the thermal insulation component 200 in the third direction z, the liquid storage sub-cavities 231 of the thermal insulation component 200 are in communication with each other, and the installation direction of the thermal insulation component 200 in the third direction z does not need to be considered during installation, which is convenient for assembly.

[0069] The first set distance c1 and the second set distance c2 can be in the range of 3 mm to 10 mm.

[0070] The first set distance c1 and the second set distance c2 can be the same.

[0071] The liquid storage sub-cavities 231 of the thermal insulation component 200 can also be in communication with each other in other ways, for example, only a distance is formed between one end of the partition rib 212 and one end cover 220 located at the same end, and the other end of the partition rib 212 can abut against the other end cover 220. For example, between the two adjacent partition ribs 212, a distance is formed between one partition rib 212 and one end cover 220, and abuts against the other end cover 220, and the other partition rib 212 abuts against one end cover 220 and forms a distance with the other end cover 220.

[0072] In some embodiments, the volume of the cooling medium stored in the storage cavity 230 of the heat insulation component 200 is 30% to 60% of the volume of the storage cavity 230. In this way, the rigidity of the heat insulation component 200 storing the cooling medium can be avoided to be too large, and the upper limit of the expansion force requirement of the battery cell 100 can be exceeded, while the heat runaway protection effect on the battery cell 100 can be ensured.

[0073] For example, the cooling medium stored in the heat insulation component 200 can be a mixture of ethylene glycol and water, and the ratio of the two can be 1:1.

[0074] In addition to the foregoing battery module, the embodiments of the present application also provide a battery pack, which comprises the battery module described in the foregoing embodiments. The battery pack can be provided with a battery box, and the battery module can be installed in the battery box. The battery pack has the same technical effects as the foregoing battery module, has good heat runaway protection capability, and has high safety and reliability.

[0075] The principles and implementation modes of the present application are described by using specific examples in the present application. The above description of the embodiments is only used to help understand the method of the present application and its core idea. It should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, the present application can be improved and modified in several ways, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A battery module, characterized in that, The battery module includes at least two cells (100) arranged along the length of the battery module. A heat insulation component (200) is provided between two large faces (110) of two adjacent cells (100). The heat insulation component (200) has a closed liquid storage chamber (230) containing a cooling medium. The melting point of the heat insulation component (200) is higher than the normal operating temperature of the cells (100) and lower than the thermal runaway temperature of the cells (100).

2. The battery module according to claim 1, characterized in that, The heat insulation component (200) includes two first peripheral wall portions (2111) arranged along the length direction, and a plurality of partition ribs (212) arranged along the width direction of the battery module are connected between the two first peripheral wall portions (2111). The plurality of partition ribs (212) divide the liquid storage cavity (230) into a plurality of liquid storage sub-cavities (231).

3. The battery module according to claim 2, characterized in that, The partition ribs (212) are inclined relative to the first peripheral wall portion (2111), and the inclination direction of each partition rib (212) is consistent.

4. The battery module according to claim 3, characterized in that, The included angle θ between the rib (212) and the first peripheral wall portion (2111) is 20°~80°.

5. The battery module according to claim 3, characterized in that, Two adjacent ribs have opposing surfaces, and the distance d between two adjacent ribs (212) is 3mm to 20mm in the normal direction of the surfaces.

6. The battery module according to claim 2, characterized in that, Each of the liquid storage compartments (231) is interconnected.

7. The battery module according to claim 6, characterized in that, The heat insulation component (200) includes two end caps (220) arranged along the height direction of the battery module. The end caps (220) are connected to the end of the first peripheral wall portion (2111) in the height direction. There is a set distance between one end of the partition rib (212) and one end cap (220) located at the same end, and between the other end of the partition rib (212) and the other end cap (220) located at the same end.

8. The battery module according to any one of claims 1-7, characterized in that, The peripheral wall (211) of the heat insulation component (200) is a plate-like structure, and the thickness t1 of the peripheral wall (211) is 0.3mm~1mm; and / or, the baffle (212) provided in the heat insulation component (200) is a plate-like structure, and the thickness t2 of the baffle (212) is 0.3mm~1mm.

9. The battery module according to any one of claims 1-7, characterized in that, The thickness t3 of the end cap (220) of the heat insulation component (200) is 0.5mm~2mm.

10. The battery module according to any one of claims 1-7, characterized in that, The volume of the cooling medium stored in the liquid storage chamber (230) is 30% to 60% of the volume of the liquid storage chamber (230).

11. The battery module according to any one of claims 1-7, characterized in that, The heat insulation component (200) is a heat insulation component made of thermoplastic non-metallic material.

12. A battery pack, characterized in that, It includes a battery box, wherein a battery module as described in any one of claims 1-11 is installed inside the battery box.

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