Battery box and battery pack

Abstract

The invention provides a battery box and a battery pack. The battery pack comprises the battery box and a battery pack mounted in the battery box, the battery box comprises a box body, the box body comprises a side wall and a bottom wall, the space, located above the bottom wall, in the box body is a battery containing cavity used for containing a battery module, the bottom of the side wall is detachably connected with a bottom protection plate, and an electric heating film is installed between the bottom protection plate and the bottom wall so as to transfer heat into the battery containing cavity. The electric heating film is installed between the bottom protection plate and the bottom wall of the box body, the whole electric heating film is arranged on the outer side of the battery box body, heat is transmitted to the battery pack through the bottom wall of the box body, the risk of high-voltage arc discharge caused by degumming and dry burning of the heating film in the battery pack is avoided, and meanwhile the heating function of the battery box is not affected. And when the electric heating film breaks down, only the electric heating film needs to be detached and overhauled, so that the overhauling process of the electric heating film is simplified, and the operation is simple.

Description

Technical Field

[0001] The present invention relates to the field of battery core heating devices, and in particular to a battery box and a battery pack. Background Art

[0002] The life and performance of the battery are closely related to the temperature of the battery. In a low temperature environment, the rate of chemical reaction inside the battery slows down, causing the battery capacity to decrease. The lower the ambient temperature, the lower the discharge capacity of the battery. In general, the battery cannot be charged or charges slowly at low temperatures. Therefore, heating the battery in a low temperature environment is particularly important. At present, most battery boxes in the industry use electric heating films or liquid heating solutions on the side of the battery module. The main application of electric heating films on battery boxes is to paste the electric heating films on the side of the module and install them between the straps of the battery module to heat the battery module. The electric heating films installed between the straps may expand at the end of the battery cell cycle life, causing the electric heating films to fall off and cause the electric heating films to dry burn and arc. Liquid heating is to pass a certain flow of high-temperature liquid into the cold plate at the bottom of the battery to heat the bottom of the battery cell to achieve heating and temperature equalization performance of the battery pack, but the liquid heating system is complex and costly.

[0003] The Chinese utility model patent with the publication number CN210926093U discloses a constant temperature standard battery pack, which realizes the cooling and heating of the battery core placed on the thermally conductive silicone plate through the structure of the thermally conductive silicone plate-water cooling plate-electric heating film-insulating cotton installed at the bottom of the battery box. The technical solution cools the battery module through the aluminum water cooling plate. When the battery needs to be heated, the heat is transferred to the battery module through the water cooling plate and the thermally conductive silicone plate through the electric heating film. The electric heating film installed in this way can effectively prevent the electric heating film from falling off and burning dry, solving the problem of the electric heating film being easy to fall off in the prior art; the electric heating film is connected to the liquid cooling plate, replacing the complex and expensive temperature control device of the prior art that integrates liquid heat and liquid cooling, saving costs. However, the heating device in the technical solution is installed at the bottom of the box, and the battery core is placed on the thermally conductive silicone plate above the heating device. If the heating device fails, it is necessary to remove all the components placed above the heating device in the battery box, and then inspect the heating device. The operation is relatively complicated and the maintenance process is long. Summary of the invention

[0004] The purpose of the present invention is to provide a battery box to solve the problem of difficult maintenance and complicated operation of the heating device in the technical solution of the existing battery heating device; the present invention also provides a battery pack to solve the problem of difficult maintenance and complicated operation of the heating device in the technical solution of the existing battery heating device.

[0005] To achieve the above-mentioned purpose, the present invention provides a battery box, including a box body, the box body including side walls and a bottom wall, the space above the bottom wall in the box body is a battery accommodating cavity for accommodating a battery module, the bottom of the side wall is detachably connected to a bottom guard plate, and an electric heating film is installed between the bottom guard plate and the bottom wall to transfer heat to the battery accommodating cavity.

[0006] Furthermore, the lower side surface of the bottom wall is higher than the bottom surface of the side wall to form a bottom interlayer between the bottom wall and the bottom guard plate, and the electric heating film is installed in the bottom interlayer.

[0007] Furthermore, a heat insulating layer is installed in the bottom interlayer between the bottom guard plate and the electric heating film.

[0008] Furthermore, the bottom wall of the box body is a liquid cooling plate.

[0009] Furthermore, the liquid cooling plate includes a middle flow channel plate and a front end plate and a rear end plate connected to the front and rear ends of the middle flow channel plate, and the front end plate is provided with a threading hole through which the lead-out wires of the power supply heating film pass.

[0010] Furthermore, the electric heating film includes an upper film layer and a lower film layer, the heating wire is located between the upper and lower film layers and attached to the upper film layer, the upper film layer covers the middle flow channel plate, and the lower film layer covers the entire liquid cooling plate.

[0011] Furthermore, an avoidance groove is provided on the lower side surface of the front end plate at the position of the lead-out wire of the electric heating film, and a threading hole is provided at the avoidance groove. The lead-out wire of the electric heating film attached to the upper film layer passes upward from the threading hole through the avoidance groove. The avoidance groove is filled with a hot pressing sheet, and the upper side surfaces of the upper and lower film layers of the electric heating film are coated with thermosetting glue, and the electric heating film is fixed to the bottom of the liquid cooling plate as a whole by hot pressing.

[0012] Furthermore, the electric heating film is an electric heating film with power partitions, the power in the middle of the electric heating film is lower, and the power in the periphery is higher.

[0013] Furthermore, the power zones of the electric heating films are all rectangular power zones, and are divided into high-power zone, medium-power zone, and low-power zone. The high-power zone is distributed at the four corners of the electric heating film body, the low-power zone is set in the center of the electric heating film body, and the medium-power zone is located at the four sides of the electric heating film and between two adjacent high-power zones.

[0014] Beneficial effects:

[0015] The present invention changes the battery box structure in the prior art, and provides a battery box structure in which the bottom wall of the box is arranged inside the main body of the box, and generates heat by means of an electric heating film installed at the lower part of the bottom wall; the heat generated by the electric heating film is transferred to the battery pack supported by the bottom wall of the box through the bottom wall of the box. The electric heating film of the present invention is installed between the bottom guard plate and the bottom wall of the box, and the electric heating film is on the outside of the battery box as a whole, and the heat is transferred to the battery pack through the bottom wall of the box, which not only avoids the risk of high-voltage arcing caused by debonding and dry burning of the heating film in the package, but also makes it more convenient to disassemble the electric heating film without affecting the heating function of the battery box. When the electric heating film fails, it only needs to be disassembled and repaired, which simplifies the process of repairing the electric heating film and is simple to operate.

[0016] The present invention provides a battery pack, including a battery box and a battery module installed inside the battery box; the battery box includes a box body, the box body includes side walls and a bottom wall, the space above the bottom wall in the box body is a battery accommodating cavity for accommodating the battery module, the bottom of the side wall is detachably connected with a bottom guard plate, and an electric heating film is installed between the bottom guard plate and the bottom wall to transfer heat to the battery accommodating cavity.

[0017] Furthermore, the lower side surface of the bottom wall is higher than the bottom surface of the side wall to form a bottom interlayer between the bottom wall and the bottom guard plate, and the electric heating film is installed in the bottom interlayer.

[0018] Furthermore, a heat insulating layer is installed in the bottom interlayer between the bottom guard plate and the electric heating film.

[0019] Furthermore, the bottom wall of the box body is a liquid cooling plate.

[0020] Furthermore, the liquid cooling plate includes a middle flow channel plate and a front end plate and a rear end plate connected to the front and rear ends of the middle flow channel plate, and the front end plate is provided with a threading hole through which the lead-out wires of the power supply heating film pass.

[0021] Furthermore, the electric heating film includes an upper film layer and a lower film layer, the heating wire is located between the upper and lower film layers and attached to the upper film layer, the upper film layer covers the middle flow channel plate, and the lower film layer covers the entire liquid cooling plate.

[0022] Furthermore, an avoidance groove is provided on the lower side surface of the front end plate at the position of the lead-out wire of the electric heating film, and a threading hole is provided at the avoidance groove. The lead-out wire of the electric heating film attached to the upper film layer passes upward from the threading hole through the avoidance groove. The avoidance groove is filled with a hot pressing sheet, and the upper side surfaces of the upper and lower film layers of the electric heating film are coated with thermosetting glue, and the electric heating film is fixed to the bottom of the liquid cooling plate as a whole by hot pressing.

[0023] Furthermore, the electric heating film is an electric heating film with power partitions, the power in the middle of the electric heating film is lower, and the power in the periphery is higher.

[0024] Furthermore, the power zones of the electric heating films are all rectangular power zones, and are divided into high-power zone, medium-power zone, and low-power zone. The high-power zone is distributed at the four corners of the electric heating film body, the low-power zone is set in the center of the electric heating film body, and the medium-power zone is located at the four sides of the electric heating film and between two adjacent high-power zones.

[0025] Beneficial effects:

[0026] The present invention changes the structure of the battery box body in the battery pack of the prior art, and provides a battery pack, including the above-mentioned battery box and a battery module installed in the battery box, and generates heat through an electric heating film installed at the lower part of the bottom wall of the box body; the heat generated by the electric heating film is transferred to the battery module supported by the bottom wall of the box body through the bottom wall of the box body. The electric heating film of the present invention is installed between the bottom guard plate and the bottom wall of the box body, and the electric heating film is on the outside of the battery box body as a whole, and the heat is transferred to the battery pack through the bottom wall of the box body. The electric heating film can be disassembled more conveniently without affecting the heating function of the battery box. When the electric heating film fails, it only needs to be disassembled and repaired, which simplifies the process of repairing the electric heating film and is simple to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the exploded structure of a battery box with the bottom wall facing upward;

[0028] Figure 2 It is a structural schematic diagram of a battery box body and a bottom wall of the box body, with the bottom wall placed upward;

[0029] Figure 3 This is a structural diagram of the electric heating film of the battery box.

[0030] In the figure: 1. battery box body; 101. box side wall; 102. box bottom wall; 1021. middle flow channel plate; 1022. front end plate; 1023. rear end plate; 104. avoidance groove; 2. threading hole; 3. electric heating film; 301. lead wire; 302. upper film layer; 303. lower film layer; 304. high power area; 305. medium power area; 306. low power area; 4. insulation layer; 5. bottom guard plate; 6. hot pressing sheet; 7. battery control module (BMS); 8. mounting ear plate; 801. connection hole; 9. hook. DETAILED DESCRIPTION

[0031] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0032] The principle of the present invention is to install the battery module in the battery accommodating cavity on the bottom wall of the battery box body, install a bottom protective plate on the bottom of the side wall of the battery box body, and arrange the electric heating film between the bottom wall of the battery box body and the bottom protective plate. The heat generated by the electric heating film is transferred to the battery accommodating cavity through the bottom wall of the battery box body. If the electric heating film fails, the electric heating film can be quickly repaired by removing the bottom protective plate installed on the bottom of the side wall of the battery box body.

[0033] Based on the above concepts and principles, the present invention provides multiple embodiments of the battery box for illustration.

[0034] In a basic embodiment, Figure 1 In the embodiment shown, the battery box body 1 includes a side wall 101 and a bottom wall 102. The space above the bottom wall in the box is a battery receiving cavity for installing a battery module. A bottom guard plate 5 is installed at the bottom of the side wall 102. An electric heating film 3 is installed between the bottom guard plate 5 and the bottom wall 102. The heat generated by the electric heating film 3 is transferred to the battery receiving cavity through the bottom wall 102.

[0035] On the basis of the above embodiments, in one embodiment, a groove is provided on the bottom guard plate 5 to accommodate the electric heating film 3, and is installed together with the electric heating film 3 at the bottom of the battery box side wall 101, so that the battery accommodating cavity is heated by the electric heating film 3 installed in the groove of the bottom guard plate 5. Due to the thickness of the bottom guard plate 5, the groove space on the bottom guard plate 5 is limited, and it may not be possible to place a better electric heating film 3 and related insulation devices, resulting in low heat utilization efficiency. In a more preferred embodiment, such as Figure 1 In the embodiment shown, the lower side surface of the bottom wall 102 is higher than the bottom surface of the side wall 101, and a bottom interlayer is formed between the bottom wall 102 and the bottom guard plate 5. The electric heating film 3 is arranged inside the interlayer, and the accommodating space of the interlayer is larger, so that the installation is more convenient, and other thermal insulation protection devices can be further installed.

[0036] On the basis of the above embodiment, in one embodiment, the electric heating film 3 is installed in the interlayer between the bottom wall 102 and the bottom guard plate 5, and the interlayer is blocked by the bottom guard plate 5. In an optimized embodiment, as Figure 1 In the provided embodiment, a heat insulating layer 4 is further provided between the electric heating film 3 and the bottom guard plate 5, so that the heat loss of the electric heating film can be prevented and the heat utilization efficiency is improved.

[0037] Based on the above embodiment, in one embodiment, the bottom wall 102 of the box body is a steel plate. In a more preferred embodiment, Figure 1-2In the provided embodiment, a liquid cooling plate is used as the bottom wall 102 of the battery box. In this way, the material of the liquid cooling plate itself can better transfer the heat generated by the electric heating film 3 to the battery accommodating cavity; when the battery module needs to be cooled, coolant can also be introduced into the liquid cooling plate to cool the battery module.

[0038] Based on the above embodiment, in one embodiment, the lead wire 301 of the electric heating film 3 is connected to the battery control module (BMS) 7 through the threading hole set on the box body of the battery box. Since the lead wire is not guided, the wire arrangement may be chaotic, which may cause the electric heating film to malfunction. In a more preferred embodiment, Figure 2 In the provided embodiment, the liquid cooling plate serving as the bottom wall 102 of the battery box includes a middle flow channel plate 1021 and a front end plate 1022 and a rear end plate 1023 located at both ends of the middle flow channel plate. A threading hole 2 for the lead-out wire 301 of the electric heating film 3 to pass through is provided at the front end plate 1022. In this way, the lead-out position of the lead-out wire 301 of the electric heating film 3 is fixed, the wire arrangement is clear, and disassembly and maintenance are convenient.

[0039] Based on the above embodiments, in one embodiment, Figure 3 In the provided embodiment, the electric heating film 3 includes an upper film layer 302 and a lower film layer 303, the heating wire is arranged between the upper and lower film layers and installed on the upper film layer 302, the area of ​​the upper film layer 302 covers the middle flow channel plate, and the area of ​​the lower film layer 303 covers the entire liquid cooling plate.

[0040] On the basis of the above embodiment, in one embodiment, the front end plate 1022 is a planar structure with only a threading hole 2. After the lead wire 301 of the electric heating film 3 passes through the threading hole 2, the electric heating film 3 is adhered to the liquid cooling plate by adhesive. Due to the existence of the lead wire 301 of the electric heating film, the electric heating film 3 cannot be flatly attached to the liquid cooling plate. In a more preferred embodiment, Figure 1 , Figure 3 The provided embodiment is used to hot-press and fix the electric heating film 3 as a whole to the bottom of the liquid cooling plate; the front end plate 1022 of the liquid cooling plate is provided with an avoidance groove 104 at the position where the threading hole 2 is opened, and the electric heating film guide wire 301 passes through the threading hole 2 on the avoidance groove 104, so that the lead wire 301 on the electric heating film 3 can be placed in the avoidance groove 102, and the electric heating film 3 can be flatly pasted on the liquid cooling plate; a hot pressing sheet 6 is also provided in the avoidance groove 104, and the upper side surfaces of the upper and lower film layers of the electric heating film 3 are coated with thermosetting glue, which is used to hot-press and fix the electric heating film 3 as a whole to the bottom of the liquid cooling plate.

[0041] On the basis of the above embodiments, in one embodiment, an electric heating film 3 with heating wires evenly arranged on the electric heating film is used to heat the battery module. Due to the different heat dissipation of various parts of the battery module, the electric heating film 3 with evenly arranged heating wires may have insufficient heat required by some battery modules during the heating process, or may have excessive heat. In an optimized embodiment, as Figure 3 In the provided embodiment, the electric heating film 3 is an electric heating film 3 with different power partitions, and the heat dissipation of the battery module is such that the electric heating film 3 is set to a heating structure with low heating power in the middle and high heating power in the periphery.

[0042] Based on the above embodiments, in one embodiment, an electric heating film with heating wires arranged in a target shape is used, the heating efficiency of the central area of ​​the electric heating film is low, and the heating efficiency of the two layers outside the central area gradually increases. In a more preferred embodiment, Figure 3 The provided embodiment uses an electric heating film structure with more refined heating power partitioning, where the high-power zone 304 is set at the four corners of the upper film layer 302 of the electric heating film 3, the low-power zone 306 is set at the center of the upper film layer 302, and the medium-power zone 305 is set at the four sides of the upper film layer 302 and is between two adjacent high-power zones 304.

[0043] Based on the above embodiments, the present invention further provides multiple embodiments of battery packs for illustration.

[0044] In a basic embodiment, Figure 1 In the illustrated embodiment, the battery pack includes the above-mentioned battery box and a battery module installed inside the battery box.

[0045] Based on the above embodiments, Figure 1-3 In the provided embodiment, the battery pack also includes a battery control module (BMS) 7 arranged on the outside of the side wall of the battery box; a mounting ear plate 8 arranged at the bottom of the battery box side wall 101 for mounting the battery box as a whole on other components; a connecting hole 801 for bolt connection is provided on the mounting ear plate; and a hook 9 for hanging other components is also provided on the outside of the side wall of the box.

[0046] Based on the above embodiments, Figure 1In the provided embodiment, when the battery box is assembled, the lead wire 301 on the electric heating film 3 is passed through the threading hole 2 set on the front end plate 1022 of the liquid cooling plate (box bottom wall 102), and then connected to the battery control module (BMS) 7 outside the battery box body 1; the electric heating film 3 is fixed to the liquid cooling plate (box bottom wall 102) by hot pressing by using the thermosetting glue set on the upper and lower film layers of the electric heating film 3 and the hot pressing sheet 6 set in the avoidance groove 104 on the front end plate 1022 of the liquid cooling plate (box bottom wall 102). 2); after installing the thermal insulation layer 4 under the electric heating film 3, install the bottom guard plate 5 at the lower end of the side wall 101 of the box, and apply sealant to the connection position of the bottom guard plate 5 and the side wall 101 of the box for waterproof sealing; the battery control module (BMS) 7 can control the power supply of the electric heating film 3; the heat generated by the electric heating film 3 is transferred to the battery receiving cavity of the battery box through the liquid cooling plate (bottom wall 102 of the box); when the electric heating film 3 fails, it is only necessary to remove the bottom guard plate 5 and the thermal insulation layer 4 to quickly repair the electric heating film 3.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A battery box, characterized in that: The box body includes a side wall and a bottom wall. The space above the bottom wall in the box body is a battery accommodating cavity for accommodating a battery module. The bottom of the side wall is detachably connected with a bottom guard plate. An electric heating film is installed between the bottom guard plate and the bottom wall to transfer heat to the battery accommodating cavity.

2. A battery box according to claim 1, characterized in that: The lower side surface of the bottom wall is higher than the bottom surface of the side wall, so that a bottom interlayer is formed between the bottom wall and the bottom guard plate, and the electric heating film is installed in the bottom interlayer.

3. A battery box according to claim 2, characterized in that: A heat insulation layer is also arranged between the bottom guard plate and the electric heating film in the bottom interlayer.

4. A battery box according to any one of claims 1 to 3, characterized in that: The bottom wall of the box body is a liquid cooling plate.

5. A battery box according to claim 4, characterized in that: The liquid cooling plate comprises a middle flow channel plate and a front end plate and a rear end plate connected to the front and rear ends of the middle flow channel plate. The front end plate is provided with a threading hole through which the lead-out wires of the power supply heating film pass.

6. A battery box according to claim 5, characterized in that: The electric heating film comprises an upper film layer and a lower film layer, the heating wire is located between the upper and lower film layers and attached to the upper film layer, the upper film layer covers the middle flow channel plate, and the lower film layer covers the entire liquid cooling plate.

7. A battery box according to claim 6, characterized in that: The lower side of the front end plate is provided with an avoidance groove at the position of the lead-out wire of the electric heating film, and the threading hole is arranged at the avoidance groove. The lead-out wire of the electric heating film attached to the upper film layer passes through the avoidance groove and passes upward from the threading hole. The avoidance groove is filled with a hot pressing sheet, and the upper side surfaces of the upper and lower film layers of the electric heating film are coated with thermosetting glue, and the electric heating film is fixed to the bottom of the liquid cooling plate as a whole by hot pressing.

8. A battery box according to any one of claims 1 to 3, characterized in that: The electric heating film is an electric heating film with power partitions, wherein the power in the middle of the electric heating film is lower and the power in the periphery is higher.

9. A battery box according to claim 8, characterized in that: The power zones of the electric heating films are all rectangular power zones, and are divided into high power zone, medium power zone and low power zone. The high power zone is distributed at the four corners of the electric heating film body, the low power zone is set in the center of the electric heating film body, and the medium power zone is located at the four sides of the electric heating film and between two adjacent high power zones.

10. A battery pack, characterized in that: It comprises a battery box and a battery module installed inside the battery box, and the battery box is the battery box provided by any one of claims 1-9.

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