Thermal insulation pad and battery module

Abstract

The present invention relates to the field of battery technology, and specifically discloses a thermal insulation pad and a battery module. The thermal insulation pad is made of silicone material. Under the action of a preset pressure P, the compression amount of the thermal insulation pad along its thickness direction is 0, and the range of the preset pressure P is P≤0.188MPa. When the thermal insulation pad is assembled with the battery cell, the thermal insulation pad has a certain compressibility, which can absorb the tolerance during the processing and manufacturing of the battery cell, ensuring that the connection strength between the connecting row and the positive / negative pole of the battery cell is high and the welding quality is good. After the thermal insulation pad and the battery cell are assembled into a group, when the battery cell expands during use, the thermal insulation pad is not easily compressed and deformed, and the distance between two adjacent battery cells will not change, ensuring the reliability and stability of the connection between the connecting row and the battery cell, and the safety of use and electrical performance of the battery cell are good. The present invention also provides a battery module, including the above-mentioned thermal insulation pad.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a thermal insulation pad and a battery module. Background Art

[0002] In a battery module, a thermal insulation pad is usually provided between two adjacent battery cells. The thermal insulation pad between two adjacent battery cells can block the heat transfer between the two adjacent battery cells, preventing one battery cell from affecting the adjacent battery cell when thermal runaway occurs. It has the effect of heat insulation and flame retardancy, reduces the risk of thermal runaway of the battery module, and also maintains the operating temperature of the battery module within an appropriate range, extending the service life. In addition, the thermal insulation pad also has the function of shockproof and absorbing the expansion of the battery cell, preventing the battery cell from being affected by external impact, and has a good buffering effect.

[0003] However, the battery cells in the industry currently have tolerances during processing and manufacturing. The tolerance of a single battery cell along its thickness direction is about ±0.4 mm. If the number of battery cells arranged in sequence along the thickness direction of the battery cell is N, the cumulative limit tolerance can reach ±0.4*N mm. After several thermal insulation pads and several battery cells are assembled, this cumulative limit tolerance will seriously affect the welding between the connecting bar and the positive and negative electrodes of the battery cell. In addition, since the battery cell will heat up and expand during use, if the hardness of the thermal insulation pad is insufficient and the deformation is too large when under pressure, it will cause the distance between two adjacent battery cells to change, resulting in tensile stress at the welding point between the connecting bar and the positive and negative electrodes of the battery cell, reducing the safety and reliability of the battery module assembly. Summary of the invention

[0004] The purpose of the present invention is to provide a thermal insulation pad and a battery module, wherein the thermal insulation pad can absorb the tolerance during the processing and manufacturing of the battery cell, and inhibit the expansion of the battery cell during subsequent use, thereby ensuring that the distance between two adjacent battery cells remains unchanged, increasing the reliability of the connection between the connecting row and the positive and negative poles of the battery cell, and the safety and reliability of the battery module assembly are high.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] On the one hand, the present invention provides a thermal insulation pad, which is made of silicone material. Under the action of a preset pressure P, the compression of the thermal insulation pad along its thickness direction is 0, and the range of the preset pressure P is P≤0.188MPa.

[0007] Optionally, when a preset pressure P>0.188Mpa, the compression amount of the thermal insulation pad along its thickness direction is less than 5%.

[0008] Optionally, when the breakdown voltage of the thermal insulation pad is AC300V, the leakage current of the thermal insulation pad is less than 1mA.

[0009] Optionally, the thickness of the thermal insulation pad is c, and the value range of c is 0.6mm-1.0mm.

[0010] Optionally, the length of the thermal insulation pad is a, and the value range of a is 185mm-195mm.

[0011] Optionally, the width of the thermal insulation pad is b, and the value range of b is 160mm-170mm.

[0012] Optionally, the volume resistivity of the thermal insulation pad is ≥1×10 15 Ω·cm.

[0013] Optionally, the water absorption rate of the thermal insulation pad is less than 3%.

[0014] On the other hand, the present invention provides a battery module, comprising a fixing assembly, a plurality of battery cells, and a plurality of thermal insulation pads according to any of the above-mentioned schemes, wherein the battery cells and the thermal insulation pads are alternately arranged, and the two sides of the thermal insulation pads are respectively connected to one of the battery cells, and the fixing assembly bundles the plurality of battery cells and the plurality of thermal insulation pads into a group.

[0015] Optionally, a glue layer is provided between the thermal insulation pad and the battery core, and two sides of the glue layer are respectively connected to the thermal insulation pad and the battery core.

[0016] The beneficial effects of the present invention are:

[0017] The present invention provides a thermal insulation pad, which is made of organic silicon material. Under the action of a preset pressure P, the compression amount of the thermal insulation pad along its thickness direction is 0, and the range of the preset pressure P is P≤0.188MPa. When the thermal insulation pad is assembled with a battery cell, the assembly tooling of the battery will apply a large pressure (>0.188MPa) to the battery cell and the thermal insulation pad. At this time, the thermal insulation pad has a certain compressibility, which can absorb the tolerance during the processing and manufacturing of the battery cell, so that the relative position of the connecting row and the positive / negative electrode of the battery cell is fixed during welding, ensuring that the connection strength of the welding between the connecting row and the positive / negative electrode of the battery cell is high and the welding quality is better. After the thermal insulation pad and the battery cell are assembled into a group, when the battery cell expands during use, due to the high hardness of the organic silicon material and the thin thickness of the thermal insulation pad, the thermal insulation pad is not easy to be compressed and deformed again, and can effectively suppress the expansion of a single battery cell. The distance between two adjacent battery cells will not change, ensuring the reliability and stability of the connection between the connecting row and the battery cell, and the safety of use and electrical performance of the battery cell are good.

[0018] The present invention also provides a battery module, including a fixing assembly, a plurality of battery cells, and a plurality of the above-mentioned thermal insulation pads, wherein the battery cells and the thermal insulation pads are alternately arranged, and the two sides of the thermal insulation pads are respectively connected to a battery cell, and the fixing assembly bundles the plurality of battery cells and the plurality of thermal insulation pads into a group, thereby ensuring that the thermal insulation pads can be pressed by the battery cells on both sides, and the thermal insulation pads are subjected to pressure applied by the battery cells. After the plurality of battery cells and the plurality of thermal insulation pads are grouped, the spacing between two adjacent battery cells is fixed, and when the battery cells expand slightly (the pressure on the thermal insulation pads is less than 0.188Mpa), the thermal insulation pads will not deform, and the connection between the connecting row and the positive / negative poles of the battery cells is reliable and stable. In the process of grouping the battery cells and the thermal insulation pads, since the assembly tooling of the battery applies a large extrusion force to the battery cells and the thermal insulation pads, that is, the pressure on the thermal insulation pads is large (greater than 0.188Mpa), the thermal insulation pads undergo a small deformation at this time, which can absorb the tolerance of the battery cells during processing and manufacturing, and ensure the safety and operability of welding and battery module assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0020] Figure 1 A schematic diagram of the structure of the thermal insulation pad and the battery cell assembly provided in an embodiment of the present invention;

[0021] Figure 2 A front view of a thermal insulation pad provided in an embodiment of the present invention;

[0022] Figure 3 A side view of a thermal insulation pad provided in an embodiment of the present invention;

[0023] Figure 4 A front view of a battery module provided in an embodiment of the present invention;

[0024] Figure 5 A top view of a battery module provided in an embodiment of the present invention.

[0025] In the figure:

[0026] 100, thermal insulation pad; 200, battery cell; 300, end plate; 400, foam; 500, cable tie; 600, connecting bar. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature "above", "above" and "above" the second feature include the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature include the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0031] At present, the battery cells in the industry have tolerances during processing and manufacturing. The thermal insulation pad needs to be compressed when assembling the battery cells to absorb the accumulated limit tolerances of multiple battery cells and ensure that the welding between the connecting bar and the positive and negative electrodes of the battery cells is operable. In addition, the battery cells will heat up and expand during use. The thermal insulation pad needs to have sufficient hardness to reduce the change in the spacing between two adjacent battery cells and alleviate the tensile stress at the welding point between the connecting bar and the positive and negative electrodes of the battery cells, thereby increasing the safety and reliability of the battery module assembly. Therefore, it is necessary to ensure that the thermal insulation pad has a good ability to resist compression deformation when the pressure it is subjected to is small, and can undergo elastic deformation when the pressure it is subjected to is large.

[0032] For this reason, Figure 1-Figure 3 As shown, this embodiment provides a thermal insulation pad 100, which is sandwiched between two battery cells 200 arranged adjacently along a first direction, and the two side surfaces of the thermal insulation pad 100 along the first direction are respectively in contact with the end surface of a battery cell 200. The thermal insulation pad 100 is made of silicone material. Under the action of a preset pressure P, the compression amount of the thermal insulation pad 100 along its thickness direction is 0, and the range of the preset pressure P is P≤0.188MPa. Among them, the first direction and the thickness direction of the thermal insulation pad 100 are Figure 1 The X-axis direction is shown in .

[0033] When the thermal insulation pad 100 and the battery cell 200 are assembled, the battery assembly tooling will apply a relatively large pressure (>0.188MPa) to the battery cell 200 and the thermal insulation pad 100. At this time, the thermal insulation pad 100 made of silicone material has a certain compressibility, which can absorb the tolerance during the processing and manufacturing of the battery cell 200, so that the relative position of the connecting bar 600 and the positive / negative pole of the battery cell 200 is fixed during welding, ensuring that the connection strength of the welding between the connecting bar 600 and the positive / negative pole of the battery cell 200 is high and the welding quality is better. After the thermal insulation pad 100 and the battery cell 200 are assembled into a group, when the battery cell 200 expands during use, the thermal insulation pad 100 is not easily compressed and deformed due to the high hardness of the silicone material and the thin thickness of the thermal insulation pad 100, and can effectively suppress the expansion of a single battery cell 200. The distance between two adjacent battery cells 200 will not change, thereby ensuring the reliability and stability of the connection between the connecting row 600 and the battery cell 200, and the battery cell 200 has good safety and electrical performance.

[0034] As an alternative, continue to see Figure 1 and Figure 3In this embodiment, the thickness of the thermal insulation pad 100 along the first direction is c, and the value range of c is 0.6mm-1.0mm. For example, the thickness of the thermal insulation pad 100 can be 0.6mm, 0.8mm or 1.0mm, etc. The thickness of the thermal insulation pad 100 is relatively thin, and after a sufficiently large pressure is applied to the thermal insulation pad 100 along the first direction, that is, when the preset pressure P>0.188Mpa, the compression amount of the thermal insulation pad 100 along its thickness direction (that is, the first direction) is less than 5%. For example, the compression amount of the thermal insulation pad 100 can be 1%, 3%, 4.5% or 4.99%, etc. When the battery cell 200 and the thermal insulation pad 100 are assembled, since the thickness and compression of the thermal insulation pad 100 along the first direction are small, that is, the deformation of the thermal insulation pad 100 along the first direction is small, the distance between two adjacent battery cells 200 along the first direction does not change much, the positioning between the battery cell 200 and the connecting bar 600 is accurate, and the welding operation between the connecting bar 600 and the positive / negative poles of the battery cell 200 is convenient, and the safety and reliability of the assembly of the battery cell 200 and the connecting bar 600 are high. Moreover, although the deformation of the thermal insulation pad 100 along the first direction is small, it is enough to absorb the tolerance of the battery cell 200 during processing and manufacturing, making the assembled battery module more stable and reliable.

[0035] Continue to see Figure 1 and Figure 2 , the length of the thermal insulation pad 100 along the second direction is a, and the value range of a is 185mm-195mm. For example, the value of a can be 185mm, 188mm, 190mm, 192mm or 195mm, etc. The width of the thermal insulation pad 100 along the third direction is b, and the value range of b is 160mm-170mm. The value of b can be 160mm, 163mm, 166mm, 168mm or 170mm, etc. Among them, the second direction refers to Figure 1 The Y-axis direction shown in the figure, the third direction is Figure 1 The Z-axis direction shown in .

[0036] Exemplarily, in this embodiment, the length of the thermal insulation pad 100 along the second direction is 192 mm, and the width of the thermal insulation pad 100 along the third direction is 166 mm. When the extrusion force F exerted on the thermal insulation pad 100 is less than 6000 N (the extrusion force on the thermal insulation pad 100 when the battery cell 200 expands is generally less than 6000 N), the thermal insulation pad 100 has no compression deformation along the first direction. It should be noted that the area of ​​the cross section of the thermal insulation pad 100 along the YZ plane is less than or equal to the area of ​​the end face of the battery cell 200 along the first direction. Therefore, the area of ​​the contact surface between the thermal insulation pad 100 and the end face of the battery cell 200 along the first direction is the area of ​​the cross section of the thermal insulation pad 100 along the YZ plane, which is denoted as S here, S = 192mm*166mm=0.031872m 2, when the extrusion force F on the thermal insulation pad 100 is equal to 6000N, the pressure on the thermal insulation pad 100 is F / S=6000 / 0.031872≈0.188MPa. In other words, when the pressure on the thermal insulation pad 100 is less than or equal to 0.188MPa, the thermal insulation pad 100 will not deform along the first direction. The hardness of the thermal insulation pad 100 is relatively high, which can ensure that the distance between two adjacent battery cells 200 remains almost unchanged, and the position of the battery cell 200 is relatively fixed, thereby reducing the stress on the welding point between the connecting row 600 and the positive / negative pole of the battery cell 200, avoiding safety risks such as breakage and dislocation.

[0037] Furthermore, the organic silicon material used in the thermal insulation pad 100 of this embodiment has excellent thermal insulation and flame retardant properties. The flame retardant properties of the thermal insulation pad 100 meet the UL94HF-1 level for horizontal combustion and the UL94-V0 level for vertical combustion specified in UL94. Organic silicon material is a relatively cheap material on the market that can achieve the required thermal insulation and flame retardant effects of the thermal insulation pad 100, which greatly reduces the cost of the thermal insulation pad 100.

[0038] In addition, in this embodiment, when the breakdown voltage of the thermal insulation pad 100 is AC300V, the leakage current of the thermal insulation pad 100 is less than 1mA. Ensure that the thermal insulation pad 100 has a good insulation effect, insulate the two adjacent battery cells 200, and ensure electrical safety. Furthermore, at room temperature, the water absorption rate of the thermal insulation pad 100 is less than 3%. The lower the water absorption rate of the thermal insulation pad 100, the better its insulation withstand voltage performance, which is conducive to ensuring the insulation performance between the two adjacent battery cells 200 and ensuring electrical safety.

[0039] Furthermore, the volume resistivity of the thermal insulation pad 100 is ≥ 1×10 15 Ω·cm. The thermal insulation pad 100 has poor electrical conductivity and is not easy to conduct electricity, which further ensures that the thermal insulation pad 100 has better insulation performance. Therefore, the thermal insulation pad 100 in this embodiment takes into account multiple functions such as heat insulation, flame retardancy, shock absorption, and tolerance absorption, and has better performance in all aspects and lower production cost.

[0040] See also Figure 4 and Figure 5 The present embodiment also provides a battery module, which includes a fixing assembly, a plurality of battery cells 200, and a plurality of the above-mentioned thermal insulation pads 100, the battery cells 200 and the thermal insulation pads 100 are alternately arranged along a first direction, and the two sides of the thermal insulation pads 100 are respectively connected to a battery cell 200, and the fixing assembly bundles the plurality of battery cells 200 and the plurality of thermal insulation pads 100 into a group, thereby ensuring that the thermal insulation pads 100 can be pressed by the battery cells 200 on both sides, and the thermal insulation pads 100 are subjected to pressure applied by the battery cells 200.

[0041] As an optional solution, the fixing assembly includes an end plate 300 and a cable tie 500. Two end plates 300 and cable ties 500 are provided, and the two end plates 300 are respectively arranged at the two ends of all battery cells 200 along the first direction. The two cable ties 500 are wound around the end plates 300. The cable ties 500 and the end plates 300 are used to bundle a number of battery cells 200 and a number of thermal insulation pads 100 into a group to realize the assembly of the battery module. Further, the battery module also includes foam 400 and connecting bars 600. Two foam 400 are provided, and each foam 400 is sandwiched between an end plate 300 and an adjacent battery cell 200. The foam 400 can also play a role in heat insulation and absorbing the expansion force of the battery cell 200. The connecting bar 600 is connected to the positive and negative electrodes of the battery cell 200, and a number of battery cells 200 are connected in series and / or in parallel through the connecting bar 600, and a conductive connection between a number of battery cells 200 is realized through the connecting bar 600.

[0042] After the cable tie 500 bundles the end plate 300, the foam 400, the plurality of battery cells 200 and the plurality of thermal insulation pads 100 into a group, the distance between two adjacent battery cells 200 is fixed, and when the battery cell 200 expands slightly (the pressure on the thermal insulation pad 100 is less than 0.188Mpa), the thermal insulation pad 100 will not deform, and the connection between the connecting row 600 and the positive / negative electrodes of the battery cell 200 is reliable and stable. At the same time, the thermal insulation pad 100 takes into account the functions of heat insulation, flame retardancy, insulation, etc., and the battery module has high reliability and long service life. In addition, during the grouping process of the battery cell 200 and the thermal insulation pad 100, since the battery assembly tooling applies a large extrusion force to the battery cell 200 and the thermal insulation pad 100, that is, the thermal insulation pad 100 is subjected to a large pressure (greater than 0.188 MPa), the thermal insulation pad 100 undergoes a slight deformation along the first direction, which can absorb the tolerance of the battery cell 200 during processing and manufacturing, thereby ensuring the safety and operability of welding and battery module assembly.

[0043] Optionally, a glue layer (not shown in the figure) is provided between the thermal insulation pad 100 and the battery cell 200, and the two sides of the glue layer are respectively connected to the thermal insulation pad 100 and the battery cell 200. The glue layer can assist in the connection and fixation between the thermal insulation pad 100 and the battery cell 200, so as to ensure that the battery module is well fixed after grouping, and the assembly is stable and reliable. Exemplarily, the thickness of the glue layer along the first direction can be 0.05mm-0.2mm. For example, the thickness of the glue layer along the first direction can be 0.05mm, 0.1mm, 0.15mm or 0.2mm, etc. The thickness of the glue layer is also set to be thinner.

[0044] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A thermal insulation pad, characterized in that: The thermal insulation pad (100) is made of organic silicon material. Under the action of a preset pressure P, the amount of compression of the thermal insulation pad (100) along its thickness direction is 0. The range of the preset pressure P is P≤0.188 MPa.

2. The thermal insulation pad according to claim 1, characterized in that: When the preset pressure P>0.188Mpa, the compression amount of the thermal insulation pad (100) along its thickness direction is less than 5%.

3. The thermal insulation pad according to claim 1, characterized in that: When the breakdown voltage of the thermal insulation pad (100) is AC300V, the leakage current of the thermal insulation pad (100) is less than 1 mA.

4. The thermal insulation pad according to claim 1, characterized in that: The thickness of the thermal insulation pad (100) is c, and the value range of c is 0.6 mm-1.0 mm.

5. The thermal insulation pad according to claim 1, characterized in that: The length of the thermal insulation pad (100) is a, and the value range of a is 185 mm-195 mm.

6. The thermal insulation pad according to claim 1, characterized in that: The width of the thermal insulation pad (100) is b, and the value range of b is 160 mm-170 mm.

7. The thermal insulation pad according to claim 1, characterized in that: The volume resistivity of the thermal insulation pad (100) is ≥1×10 15 Ω·cm.

8. The thermal insulation pad according to claim 1, characterized in that: The water absorption rate of the thermal insulation pad (100) is less than 3%.

9. A battery module, characterized in that: It comprises a fixing component, a plurality of battery cells (200), and a plurality of thermal insulation pads (100) according to any one of claims 1 to 8, wherein the battery cells (200) and the thermal insulation pads (100) are alternately arranged, and both sides of the thermal insulation pads (100) are respectively connected to one of the battery cells (200), and the fixing component bundles the plurality of battery cells (200) and the plurality of thermal insulation pads (100) into a group.

10. The battery module according to claim 9, characterized in that: An adhesive layer is provided between the thermal insulation pad (100) and the battery core (200), and two sides of the adhesive layer are respectively connected to the thermal insulation pad (100) and the battery core (200).

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