Battery box

Abstract

To provide a battery box that can overcome a failure in the conventional art and includes an ideal safety function.SOLUTION: The present invention discloses a battery box. The battery box contains: a battery box main body; and a plurality of batteries housed in the battery box main body. The battery and an inner wall of the battery box main body are adhered by an adhesive agent, a thermal expansion coefficient of the adhesive agent is α, a unit is ppm / °C, a thermal transfer coefficient of the adhesive agent is β, a unit is W / mK and the α and the β satisfy a relational expression of 15≤α / β≤80. In the battery box, the battery box main body and the plurality of batteries housed in the battery box main body are adhered by the adhesive agent. By matching the thermal transfer coefficient and the thermal expansion coefficient of the adhesion agent, needs in the thermal conduction of the battery box is satisfied battery box, and the generation of a thermal stress cracking or a peeling of the adhesive agent due to a modulation of a temperature in a use step can be also prevented. Thus, a safety performance of the battery box can be improved.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority from a Chinese patent application bearing application number 201910748287.9 ​​and entitled "Battery Box" filed with the China Patent Office on August 14, 2019, the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the field of battery technology, and more particularly to a battery box with ideal safety performance. [Background technology]

[0003] In recent years, with the continuous development and popularization of new energy vehicles, battery boxes have gradually become more widely used and are attracting more attention. Generally, a battery box includes a battery box body and a plurality of batteries accommodated in the battery box body.

[0004] In related art, in order to improve the overall energy density of the battery box, adhesive is generally used to bond the battery box body and the battery, but in practical applications, it has been found that when meeting the thermal conductivity needs of the battery box, the temperature may fluctuate during the actual operation of the battery box and the battery, which makes it easy for the adhesive to crack or peel off due to thermal stress, affecting the safety performance of the battery box.

[0005] In view of this, it is necessary to provide a battery box with ideal safety performance. Summary of the Invention [Problem to be solved by the invention]

[0006] Through research and experiments, the inventors of the present application have discovered that the safety performance of a battery box is closely related to the thermal expansion coefficient and thermal conductivity coefficient of the adhesive. When the thermal conductivity coefficient and thermal expansion coefficient of the adhesive are matched, it is possible not only to meet the thermal conductivity needs of the battery box, but also to prevent the adhesive from cracking or peeling off due to thermal stress caused by temperature fluctuations during use of the battery box. Based on the above findings, the present invention aims to overcome the drawbacks of the prior art and provide a battery box with ideal safety performance. [Means for solving the problem]

[0007] To achieve the above object of the invention, the present application provides a battery box, including a battery box body and a plurality of batteries housed in the battery box body, the batteries and the inner wall of the battery box body are bonded with an adhesive, the adhesive has a thermal expansion coefficient α in ppm / °C and a thermal conductivity coefficient β in W / mK, and α and β satisfy the relationship 15≦α / β≦80.

[0008] In an improvement to the battery box of the present application, the thermal expansion coefficient α and thermal conductivity coefficient β of the adhesive satisfy the relationship 25≦α / β≦45, the thermal expansion coefficient α is in ppm / °C, and the thermal conductivity coefficient β is in W / mK.

[0009] As an improvement to the battery box of the present application, the thermal expansion coefficient α of the adhesive is 30 ppm / °C to 55 ppm / °C, preferably 30 ppm / °C to 45 ppm / °C, and the thermal conductivity coefficient β of the adhesive is 0.6 W / mK to 1.9 W / mK, preferably 0.8 W / mK to 1.5 W / mK.

[0010] In an improvement to the battery box of the present application, the adhesive contains a base material and a filler material.

[0011] In an improvement to the battery box of the present application, the base material is one of polyurethane, acrylic acid, and epoxy resin, and the weight percentage of the base material in the adhesive is 30% to 90%, preferably 40% to 60%, and the filler is aluminum oxide or boron nitride, and the weight percentage of the filler in the adhesive is 10% to 70%, preferably 30% to 50%.

[0012] In an improvement of the battery box of the present application, the particle size of the filler is 10 microns to 80 microns.

[0013] In the battery box of the present invention, the thickness of the adhesive is 0.5 mm to 1.5 mm.

[0014] In an improvement to the battery box of the present application, the battery is a soft package battery, and the soft package battery includes an electrode assembly, a package film, and an electrode lead, the electrode assembly is packaged within the package film, and the electrode lead is electrically connected to the electrode assembly and extends outside the package film.

[0015] In an improvement to the battery box of the present application, the battery is a hard case battery, and the hard case battery includes a battery case, an electrode assembly, and a battery top cover, the electrode assembly is housed in the battery case, the battery top cover is hermetically connected to the battery case, electrode terminals are provided on the battery top cover, and the electrode terminals are electrically connected to the electrode assembly.

[0016] In an improved battery box of the present invention, the material of the battery case is metal, and the outer surface of the battery case is coated with an insulating film.

[0017] In an improvement to the battery box of the present application, the outer surface of the battery case includes a first surface, an opening is provided in the insulating film, and at least a portion of the first surface is exposed from the insulating film through the opening and is adhered to the inner wall of the battery box body with the adhesive.

[0018] In an improvement of the battery box of the present application, the area of ​​the opening of the insulating film is A1, the area of ​​the first surface is A2, and the ratio of A1 to A2 satisfies 30%≦A1 / A2≦80%.

[0019] In the improved battery box of the present invention, the battery case is made of metal and the outer surface of the battery case is coated with an insulating film.

[0020] In an improvement to the battery box of the present application, the battery box body includes a lower box body and a box cover hermetically connected to the lower box body, and the battery and the inner wall of the lower box body are bonded together with the adhesive, and / or the battery and the inner wall of the box cover are bonded together with the adhesive.

[0021] In an improvement to the battery box of the present application, the lower box body includes a bottom plate and a side plate that is surrounded by the outer periphery of the bottom plate, and the battery and the bottom plate of the lower box body are bonded together with the adhesive.

[0022] As an improvement to the battery box of the present application, the lower box body further includes a fixing plate, which is fixedly connected to the bottom plate or the side plate, and the battery and the fixing plate of the lower box body are bonded together with the adhesive.

[0023] In an improvement of the battery box of the present application, a fluid passage is provided in the fixing plate, and a heat exchange fluid is present in the fluid passage.

[0024] In an improvement to the battery box of the present application, the box cover includes a top plate and a surrounding plate that is surrounded by the outer periphery of the top plate, and the battery and the top plate of the box cover are bonded together with the adhesive.

[0025] The present application further provides an apparatus, including the battery box according to any one of the above embodiments, wherein the battery box is used to provide electrical energy. [Effects of the Invention]

[0026] Compared to the prior art, in the battery box of the present application, the battery box body and the batteries housed therein are bonded with an adhesive, which contains a substrate material and a filler. When the adhesive has a high thermal conductivity, the adhesive contains a high filler content and a low corresponding substrate material content, resulting in good thermal conductivity, but thermal stress cracking or peeling of the adhesive due to temperature fluctuations during use of the battery box. When the adhesive has a high thermal expansion coefficient, the adhesive contains a high substrate material content and a low corresponding filler content, resulting in good thermal expansion, but it is difficult to meet the thermal conductivity needs of the battery box. In the battery box of the present application, by matching the thermal conductivity coefficient and thermal expansion coefficient of the adhesive, not only can the thermal conductivity needs of the battery box be met, but also thermal stress cracking or peeling of the adhesive due to temperature fluctuations during use of the battery box can be prevented, thereby improving the safety performance of the battery box.

[0027] Hereinafter, the battery box and its technical effects will be described in detail with reference to specific embodiments with reference to the drawings. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a schematic exploded perspective view of a first embodiment of a battery box according to the present invention. [Figure 2] FIG. 2 is a schematic assembly diagram of the first embodiment of the battery box of the present invention. [Figure 3] FIG. 3 is a schematic cross-sectional view of the battery box shown in FIG. 2 taken along line AA. [Figure 4] FIG. 4 is a schematic exploded perspective view of a second embodiment of the battery box of the present invention. [Figure 5] FIG. 5 is a cross-sectional view showing a second embodiment of the battery box of the present invention after assembly. [Figure 6] FIG. 6 is a schematic exploded perspective view of a hard case battery used in the battery box of the present invention. [Figure 7A]FIG. 7A is a schematic diagram showing a different structure of the insulating film coated on the surface of the hard case battery shown in FIG. [Figure 7B] FIG. 7B is a schematic diagram showing a different structure of the insulating film coated on the surface of the hard case battery shown in FIG. [Figure 8] FIG. 8 is a schematic exploded perspective view of a soft package battery used in the battery box of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] In order to clarify the objectives, technical solutions and technical effects of the present invention, the present invention will be described in more detail below by means of specific embodiments with reference to the drawings. It should be understood that the specific embodiments described herein are only for the purpose of interpreting the present invention, and are not intended to limit the present invention.

[0030] As shown in FIGS. 1 to 3, a first embodiment of the battery box of the present application includes a battery box body 10 and a plurality of batteries 20 housed in the battery box body 10, the batteries 20 and the inner wall of the battery box body 10 are bonded together with an adhesive 40, the adhesive 40 having a thermal expansion coefficient α in ppm / °C and a thermal conductivity coefficient β in W / mK, where α and β satisfy the relation 15≦α / β≦80, and preferably 25≦α / β≦45.

[0031] The battery box body 10 includes a lower box body 100 and a box cover 102 attached to the lower box body 100, and the lower box body 100 and the box cover 102 are sealed by a sealing ring 104. The lower box body 100 includes a bottom plate 106 and a side plate 108 surrounded by the outer periphery of the bottom plate 106, and the box cover 102 includes a top plate 110 and an outer plate 112 surrounded by the outer periphery of the top plate 110.

[0032] In the first embodiment of the present application, the battery 20 and the inner wall (bottom plate 106) of the lower box body 100 are bonded with adhesive 40. Depending on actual needs, the battery 20 may also be bonded to the inner wall (top plate 110) of the box cover 102 with adhesive 40.

[0033] 4 and 5 show a second embodiment of a battery box according to the present invention. Unlike the first embodiment in which the battery 20 is directly bonded to the bottom plate 106 of the lower box body 100 of the battery box body 10 with adhesive 40, in the second embodiment of the present invention, a fixing plate 114 is provided on the bottom plate 106 of the lower box body 100 of the battery box body 10, and the fixing plate 114 is installed to facilitate removal. The fixing plate 114 is fixedly connected to the bottom plate 106 or the side plate 108, and the battery 20 and the fixing plate 114 of the lower box body 100 are bonded together with adhesive 40. In addition, to achieve better cooling or heating, a fluid passage (not shown) may be provided in the fixing plate 114, and a heat exchange fluid is present in the fluid passage.

[0034] In the battery box of the present application, there is no special requirement for the type of battery 20, and it may be a hard case battery or a soft package battery.

[0035] As shown in FIG. 6 , according to one embodiment of the present application, the battery 20 is a hard-case battery, and includes a battery case 200, an electrode assembly 202, and a battery top cover 204, the electrode assembly 202 is housed in the battery case 200, the battery top cover 204 is hermetically connected to the battery case 200, and an electrode terminal 206 is provided on the battery top cover, and the electrode terminal 206 is electrically connected to the electrode assembly 202.

[0036] As shown in FIGS. 7A and 7B , to further ensure the safety of the battery box, the hard-case battery is made of metal, and the surface of the battery case 200 is coated with a layer of insulating film 210 (e.g., PET film). The outer surface of the battery case 200 includes a first surface 208. An opening 212 is formed in the insulating film 210. At least a portion of the first surface 208 is exposed through the opening 212 and is bonded to the inner wall (bottom plate 106 or side plate 108) of the battery box body 10 with adhesive 40. The opening 212 is formed to expose a portion of the metal and improve the adhesive strength of the hard-case battery. According to one preferred embodiment of the present application, the area of ​​the opening 212 in the insulating film 210 is defined as A1, the area of ​​the first surface 208 is defined as A2, and the ratio of A1 to A2 satisfies 30%≦A1 / A2≦80%.

[0037] As can be understood, according to another embodiment of the present application, the material of the battery case 200 is metal, and the outer surface of the battery case 200 is coated with an insulating film or with one insulating layer (e.g., epoxy resin).

[0038] As shown in FIG. 8 , according to another embodiment of the present application, the battery 20 is a soft package battery, which includes a packaging film 300, an electrode assembly 202, and an electrode lead 304, wherein the electrode assembly 202 is packaged within the packaging film 300, and the electrode lead 304 is electrically connected to the electrode assembly 202 and extends outside the packaging film 300.

[0039] The battery box of the present application will be described in more detail below with ratios, examples and corresponding test results.

[0040] 1. Thermal conductivity test (1) The thermal conductivity test was performed according to ASTM D5470. The test equipment was a Hot Disk 2550s. The test parameters were set according to the test method of the equipment, and the time interval between successive tests was 5 minutes. (2) Sample production During the sample production process, it is necessary to confirm that the ratio of components A and B is correct (no color difference). When mixing the adhesive, to avoid any residual air bubbles, use an adhesive gun and static mixing head to dispense the adhesive, or mix the adhesive manually, then use a vacuum degassing machine to mix and degas for 2 minutes. Furthermore, the adhesive is placed in a hard block production jig, and the adhesive is allowed to flow as evenly as possible, with the diameter or side length of the test block being at least 36 mm, and the thickness being at least 6 mm. (3) Curing conditions The sample is baked in an oven (the curing temperature and time are specifically based on MS), and after removal, it is left at room temperature for at least 2 hours, and then the test is started. (4) Testing requirements Testing is performed using hot disk 2550s, and the median value is taken from five parallel samples.

[0041] 2. Thermal expansion coefficient test (1) Refer to GB / T 1036 to prepare samples, and measure the two samples after conditioning with a vernier caliper to the nearest 0.02 mm; (2) Glue a piece of iron to the bottom end of the sample to prevent shrinkage, and retest the length of the sample. (3) Use the same dilatometer for each sample, carefully place it in an environment (-32℃~-28℃), and if using a liquid bath, ensure that the height of the sample is at least 50mm below the liquid surface. Maintain the temperature of the liquid bath between (-32℃~-28℃), and after the sample temperature and the constant temperature bath temperature are balanced and the scale of the measuring instrument has stabilized for 5 minutes, record the temperature and scale. (4) Under conditions that do not cause vibration, carefully place the quartz dilatometer in a +30°C environment. If a liquid bath is used, ensure that the height of the sample is at least 50mm below the liquid surface. Maintain the temperature of the liquid bath at a constant temperature (28°C~32°C). After the sample temperature and the temperature of the constant temperature bath are balanced and the scale of the measuring instrument is stabilized, record the data. (5) Divide the data to get the result.

[0042] 3. Testing the shear strength of adhesives (1) Size The shear test specimens should be manufactured in accordance with GB / T 7124. The adhesive members should be positioned accurately using a fixture. The adhesive width should be limited by Teflon tape, and the adhesive length should be controlled to 12.5±0.5mm. Unless otherwise required, the adhesive layer thickness should be designed to be 0.25±0.05mm. It can also be controlled by inserting spacer wires, with the wires parallel to the force direction. (2) Base material The test specimens are made of electrophoretic steel, 3003Al, 6063Al, PET blue film, and other substrates. The surfaces to be bonded must be free of oil and other contaminants; any contaminants must be cleaned before bonding. The surface energy of the blue film must be 28-32 dyn, and that of the aluminum must be 30-34 dyn. The surface of the aluminum substrate must not be specially treated (if it is a non-oxidized aluminum plate coated with a film, it must be exposed to air for at least three days before use). The PET blue film is wrapped around the aluminum test specimen, and no air bubbles are allowed. (3) Adhesive Mixing Requirements During the sample production process, it is necessary to confirm that the ratio of components A and B is correct (no color difference). When mixing the adhesive, in order to avoid any residual air bubbles, the adhesive is dispensed using an adhesive gun and static mixing head, or the adhesive is mixed manually, and then mixed and degassed for 2 minutes using a vacuum degasser before the sample is produced. (4) Manufacturing process The adhesive sample preparation should be completed within the specified operation time, and care should be taken to remove excess adhesive. The adhesive sample is baked in an oven (the curing temperature and time are specifically based on MS), and then left at room temperature for at least 2 hours after removal, before starting the test. (5) Testing requirements The tensile tester performs the test at a constant test speed of 5 mm / min. To ensure that the force applied to the sample is parallel to the adhesive surface, one washer with the same thickness as the test specimen must be placed on each of the upper and lower test clamp heads. If the pull-out displacement needs to be tested, it must be measured using an extensometer.

[0043] 4. Maximum battery temperature By placing a temperature sensor on the top cover of the battery, the battery temperature can be monitored in real time during the operation of the battery and data can be read.

[0044] Depending on actual needs, the requirements are defined as being met when the shear strength is 8 MPa or more and the maximum temperature of the battery is 50°C or less.

[0045] The composition of the adhesive in the battery box of the present invention, the test results of the relevant parameters, and the performance test results will be described in detail below with reference to examples and comparative examples.

[0046] Table 1. Compositions of adhesives in Examples 1 to 21 and Comparative Examples 1 to 9 of the present application, and results of parameter tests and performance tests. [Table 1] [Table 2] [Table 3]

[0047] As can be seen from the above examples and the corresponding experimental results shown in Table 1, in the battery box of the present application, the battery box body and the batteries housed therein are bonded with an adhesive, and the adhesive contains a substrate material and a filler. When the thermal conductivity coefficient of the adhesive is high, the adhesive contains a high filler content and a low corresponding substrate material content, resulting in good thermal conductivity, but the adhesive may crack or peel off due to thermal stress during use of the battery box due to temperature fluctuations. When the thermal expansion coefficient of the adhesive is high, the adhesive contains a high substrate material content and a low corresponding filler content, resulting in good thermal expansion, but it is difficult to meet the thermal conductivity needs of the battery box. In the battery box of the present application, matching the thermal conductivity coefficient and thermal expansion coefficient of the adhesive not only meets the thermal conductivity needs of the battery box, but also prevents the adhesive from cracking or peeling off due to thermal stress during use of the battery box due to temperature fluctuations, thereby improving the safety performance of the battery box.

[0048] The present application further provides a device, including the battery box of any one of the above embodiments, the battery box being used to provide electrical energy. The device may be a device that uses a battery box, such as a vehicle (especially an electric vehicle), a steamship, an aircraft, etc., and the battery box provides electrical energy to the device.

[0049] Based on the disclosure and teachings of the above specification, those skilled in the art can further make appropriate changes and modifications to the above embodiments. Therefore, the present application is not limited to the specific embodiments disclosed and described above, and any modifications and changes to the present application should also be included within the scope of the claims of the present application. In addition, although some specific terms are used in this specification, these terms are merely for the purpose of facilitating explanation and are not intended to limit the present application. [Explanation of symbols]

[0050] 10 Battery box body 100 Lower box body 102 Box Cover 104 Sealing Ring 106 Bottom plate 108 Side Panel 110 Top Plate 112 Surrounding board 114 Fixed plate 20 batteries 200 Battery Case 202 Electrode assembly 204 Battery top cover 206 Electrode terminal 208 1st surface 210 insulating film 212 Aperture 300 packaging film 304 Electrode Lead 40 Adhesive

Claims

1. A battery box including a battery box body and a plurality of batteries housed in the battery box body, wherein the batteries and an inner wall of the battery box body are bonded with an adhesive, the adhesive has a thermal expansion coefficient α in ppm / °C, the adhesive has a thermal conductivity coefficient β in W / mK, and α and β satisfy the relational expression 15≦α / β≦80; the battery is a hard case battery, the hard case battery including a battery case, an electrode assembly, and a battery top cover, the electrode assembly being accommodated in the battery case, the battery top cover being hermetically connected to the battery case, electrode terminals being provided on the battery top cover, and the electrode terminals being electrically connected to the electrode assembly; The battery case is made of a metal, and an outer surface of the battery case is coated with an insulating film; an outer surface of the battery case includes a first surface, an opening is formed in the insulating film, and at least a portion of the first surface is exposed from the insulating film through the opening and is bonded to an inner wall of the battery box body with the adhesive; The thermal expansion coefficient α is tested according to GB / T 1036, and the thermal conductivity coefficient β is tested according to ASTM D5470.

2. 2. The battery box according to claim 1, wherein the adhesive has a thermal expansion coefficient α and a thermal conductivity coefficient β that satisfy the relationship 25≦α / β≦45, the thermal expansion coefficient α being expressed in ppm / °C, and the thermal conductivity coefficient β being expressed in W / mK.

3. 3. The battery box according to claim 1, wherein the adhesive has a thermal expansion coefficient α of 30 ppm / ° C. to 55 ppm / ° C., and a thermal conductivity coefficient β of 0.6 W / mK to 1.9 W / mK.

4. 4. The battery box according to claim 3, wherein the adhesive has a thermal expansion coefficient α of 30 ppm / ° C. to 45 ppm / ° C., and a thermal conductivity coefficient β of 0.8 W / mK to 1.5 W / mK.

5. 2. The battery box according to claim 1, wherein the adhesive contains a base material and a filler, and the base material of the adhesive is 30% to 90% by weight, and the filler of the adhesive is 10% to 70% by weight.

6. 6. The battery box according to claim 5, wherein the base material of the adhesive is 40% to 60% by weight, and the filler material of the adhesive is 30% to 50% by weight.

7. 6. The battery box according to claim 5, wherein the base material is one of polyurethane, acrylic acid, and epoxy resin, and the filler is aluminum oxide or boron nitride.

8. 8. The battery box according to claim 1, wherein the adhesive has a thickness of 0.5 mm to 1.5 mm.

9. 2. The battery box according to claim 1, wherein an area of ​​the opening of the insulating film is A1, an area of ​​the first surface is A2, and a ratio of A1 to A2 satisfies 30%≦A1 / A2≦80%.

10. The battery box according to any one of claims 1 to 9, wherein the battery box body includes a lower box body and a box cover hermetically connected to the lower box body, and the battery and an inner wall of the lower box body are bonded together with the adhesive, and / or the battery and an inner wall of the box cover are bonded together with the adhesive.

11. The battery box according to claim 10, wherein the lower box body includes a bottom plate and a side plate surrounded by the outer periphery of the bottom plate, and the battery and the bottom plate of the lower box body are bonded together with the adhesive.

12. The battery box according to claim 11, wherein the lower box body further includes a fixing plate, the fixing plate being fixedly connected to the bottom plate or the side plate, and the battery and the fixing plate of the lower box body being bonded together with the adhesive.

13. The battery box according to claim 12, wherein the fixing plate is provided with a fluid passage, and the fluid passage contains a heat exchange fluid.

14. The battery box according to any one of claims 10 to 13, wherein the box cover includes a top plate and an enclosure plate that is surrounded by the outer periphery of the top plate, and the battery and the top plate of the box cover are bonded together with the adhesive.

15. A device, comprising the battery box according to any one of claims 1 to 14, said battery box being used for providing electrical energy.

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