Battery pack

Abstract

A battery pack, comprising: a battery box, a battery cell assembly (100), and an expansion beam (200). The battery cell assembly (100) is arranged in the battery box, and the expansion beam (200) is fixed in the battery box. The expansion beam (200) comprises a first side wall (210) and a second side wall (220) that are arranged opposite each other, the first side wall (210) being bonded to the battery cell assembly (100). Said bonding greatly improves the reliability of the connection between the expansion beam (200) and the battery cell assembly (100).

Description

battery pack

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on April 26, 2024, with application number 202420895606.5. The entire contents of the above application are incorporated by reference into this application.

[0002] Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a battery pack.

[0004] Background Art

[0005] In related technologies, an expansion beam is usually provided in the battery box. The two ends of the expansion beam are respectively welded to the two inner walls of the battery box, and the side walls of the expansion beam abut against the ends of the battery cell assembly. When the battery cell assembly expands during charging and discharging, the expansion beam applies a force to the battery cell assembly in the opposite direction of the expansion, so that the battery cell assembly is in a clamped state, and at the same time, deformation of the battery box can be avoided.

[0006] Technical issues

[0007] The expansion beam and the battery cell assembly are connected only by extrusion force and friction force, which makes the reliability of the connection between the two poor. When the battery pack collides or vibrates, it is easy to cause the connection between the expansion beam and the battery cell assembly to fail, and the expansion beam cannot apply the above-mentioned force to the battery cell assembly.

[0008] Technical Solutions

[0009] An embodiment of the present application provides a battery pack, comprising:

[0010] Battery box;

[0011] A battery cell assembly, wherein the battery cell assembly is arranged in the battery box;

[0012] An expansion beam is fixed in the battery box, and the expansion beam includes a first side wall and a second side wall that are arranged opposite to each other, and the first side wall is bonded to the battery core assembly.

[0013] Beneficial effects

[0014] The battery pack provided in the present application comprises an expansion beam comprising a first side wall and a second side wall arranged opposite to each other, wherein the first side wall is bonded to the battery cell assembly. When the battery pack collides or vibrates, the probability of failure of the connection between the expansion beam and the battery cell assembly is low, thereby greatly improving the reliability of the connection between the expansion beam and the battery cell assembly.

[0015] BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a schematic cross-sectional view of an expansion beam and a battery cell assembly according to an embodiment of the present application;

[0017] FIG2 is a first structural diagram of an expansion beam provided in an embodiment of the present application;

[0018] FIG3 is a schematic structural diagram of an expansion beam, a battery cell assembly, and a BMS provided in an embodiment of the present application;

[0019] FIG4 is a second structural schematic diagram of the expansion beam provided in an embodiment of the present application.

[0020] In the picture:

[0021] 100, battery cell assembly; 200, expansion beam; 210, first side wall; 211, groove; 212, glue injection port; 220, second side wall; 221, mounting hole; 230, weight reduction cavity; 240, reinforcing rib; 300, glue; 400, BMS; 500, connecting wire; 600, connecting row; 510, first protrusion; 511, first socket; 520, second mounting piece; 530, second protrusion; 531, second socket; 540, first mounting piece; 700, fixing piece.

[0022] Modes for Carrying Out the Invention

[0023] This embodiment provides a battery pack that can improve the reliability of the connection between the expansion beam and the battery cell assembly.

[0024] As shown in Figures 1 to 3, the battery pack includes a battery box, a battery cell assembly 100 and an expansion beam 200, wherein the battery cell assembly 100 is arranged in the battery box, the two ends of the expansion beam 200 are fixedly connected to the two inner side walls of the battery box respectively, and / or the bottom of the expansion beam 200 is fixedly connected to the inner bottom wall of the battery box, and the expansion beam 200 includes a first side wall 210 and a second side wall 220 arranged opposite to each other, and the first side wall 210 is bonded to the battery cell assembly 100.

[0025] Based on the above design, the first side wall 210 of the expansion beam 200 is bonded to the battery cell assembly 100. When the battery pack collides or vibrates, the probability of failure of the connection between the expansion beam 200 and the battery cell assembly 100 is low, which greatly improves the reliability of the connection between the expansion beam 200 and the battery cell assembly 100.

[0026] The battery cell assembly 100 can be sandwiched between the expansion beam 200 and the inner wall of the battery box, or can be sandwiched between two expansion beams 200, depending on the actual application situation.

[0027] Existing expansion beams are roughly divided into two structures: expansion beams with rectangular longitudinal sections and expansion beams with L-shaped longitudinal sections. When the expansion beam with a rectangular longitudinal section applies a force opposite to the expansion direction to the battery cell assembly, concentrated stress will be generated at the welds at both ends of the expansion beam, which may cause cracking of the welds in severe cases. Therefore, the thickness of this type of expansion beam is generally thicker to improve its anti-expansion ability; the horizontal section of the expansion beam with an L-shaped longitudinal section can support the vertical section, so this type of expansion beam has better anti-expansion ability, but this type of expansion beam needs to occupy a larger space in the battery box, which is not conducive to improving the energy density of the battery pack.

[0028] As shown in Figures 1 to 3, the second side wall 220 is arranged at an angle, and the angle between the second side wall 220 and the bottom surface of the expansion beam 200 is smaller than the angle between the second side wall 220 and the top surface of the expansion beam 200, that is, the second side wall 220 is inclined toward the battery cell assembly 100. When the battery cell assembly 100 expands, the second side wall 220 can support the expansion beam 200, thereby improving the anti-expansion ability of the expansion beam 200. In addition, this structural arrangement also avoids occupying too much space in the battery box, which is beneficial to improving the energy density of the battery pack.

[0029] The angle between the second side wall 220 and the bottom surface of the expansion beam 200 ranges from 80° to 85°. For example, the angle can be 80°, 83° or 85°, etc. Taking 85° as an example, it can not only make the expansion beam 200 have better anti-expansion ability, but also avoid occupying too much internal space of the battery box.

[0030] As shown in Figures 1 to 3, a groove 211 with an opening toward the battery cell assembly 100 is provided on the first side wall 210, and the groove 211 is filled with adhesive 300. The first side wall 210 is bonded to the battery cell assembly 100 through the adhesive 300 to reduce the total width of the expansion beam 200 and the battery cell assembly 100 after bonding, thereby achieving the effect of saving the internal space of the battery box.

[0031] As shown in Figures 1 to 3, there are multiple grooves 211, for example, two, four, six, seven, etc. The multiple grooves 211 are spaced apart along the extension direction of the expansion beam 200, and each groove 211 is filled with adhesive 300 to increase the number of bonding points between the first side wall 210 and the battery cell assembly 100, thereby improving the reliability of the bonding between the expansion beam 200 and the battery cell assembly 100. In addition, when one expansion beam 200 is bonded to two or more battery cell assemblies 100, the multiple grooves 211 can correspond to different battery cell assemblies 100. In this embodiment, there are six grooves 211, and one expansion beam 200 is bonded to two battery cell assemblies 100. Each battery cell assembly 100 corresponds to three grooves 211, that is, each battery cell assembly 100 has three bonding points with the first side wall 210. This not only improves the reliability of the bonding between each battery cell assembly 100 and the expansion beam 200, but also fully utilizes the internal space of the battery box, thereby increasing the energy density of the battery pack. Of course, in other embodiments, one expansion beam 200 may be bonded to three or even more battery cell assemblies 100 , and the number of grooves 211 corresponding to different battery cell assemblies 100 may be the same or different, depending on the application.

[0032] As shown in Figures 1 to 3, a glue injection port 212 is provided on the side wall of the groove 211, through which the adhesive 300 can be injected into the groove 211. The glue injection port 212 can be located on the top surface of the expansion beam 200 or on the side of the first side wall 210. In this embodiment, the glue injection port 212 is located on the top surface of the expansion beam 200 to facilitate glue injection.

[0033] In this embodiment, each groove 211 is provided with a glue injection port 212. In other implementation schemes, some of the grooves 211 may be provided with a glue injection port 212, while the remaining grooves 211 may not have a glue injection port 212; or some of the grooves 211 may have a glue injection port 212, and all the grooves 211 may be interconnected or not interconnected; or all the grooves 211 may not have a glue injection port 212, depending on actual assembly requirements.

[0034] As shown in FIG. 1 to FIG. 3 , a weight reduction cavity 230 is provided between the first side wall 210 and the second side wall 220 to reduce the weight of the expansion beam 200 , thereby reducing the weight of the battery pack and improving the energy density of the battery pack.

[0035] As shown in Figures 1 to 3, expansion beam 200 also includes at least one reinforcing rib 240, which is disposed within weight-reducing cavity 230. The two ends of rib 240 are fixedly connected to first sidewall 210 and second sidewall 220, respectively. This structural arrangement improves the expansion resistance of expansion beam 200 without occupying additional space within the battery box. In this embodiment, three reinforcing ribs 240 are provided within weight-reducing cavity 230. In other embodiments, one, two, five, or even more reinforcing ribs 240 may be provided, depending on the height of expansion beam 200.

[0036] The battery pack also includes a connecting bar 600, a detection element (such as a temperature sensor or a voltage sensor), a connecting wire 500 and a battery management system (BMS). The connecting bar 600 is an element with a conductive function such as a copper bar. The multiple battery cells in the battery cell assembly 100 are electrically connected through the connecting bar 600. The detection element is arranged on the connecting bar 600 or on the battery cell and is configured to detect the real-time status of the battery cell, such as the temperature or voltage. The connecting wire 500 is respectively connected to the detection element and the BMS400 to transmit the data signal detected by the detection element to the BMS400, thereby realizing real-time monitoring of the battery module.

[0037] The connecting bar 600 and / or the connecting wire 500 are fixed on the second side wall 220, eliminating the need for a bracket for fixing the connecting bar 600 and / or the connecting wire 500 in the battery box, thereby reducing weight and cost.

[0038] As shown in Figures 1 to 4, the second side wall 220 is provided with a mounting hole 221. When fixing the connecting bar 600 to the second side wall 220, a fixing member 700 such as a pin or bolt can be passed through the connecting bar 600 and fixed in the mounting hole 221. When fixing the connecting wire 500 to the second side wall 220, a fixing member 700 such as a pin or bolt can be fixed in the mounting hole 221, and the connecting wire 500 can be fixed to the fixing member 700 by winding or bonding. Of course, if the height space of the battery box is sufficient, the mounting hole 221 can also be opened on the top surface of the expansion beam 200, that is, the connecting bar 600 and / or the connecting wire 500 are fixed to the top surface of the expansion beam 200 through the fixing member 700, depending on the internal space conditions of the battery box.

[0039] The battery pack also includes a mounting structure, and the BMS400 is mounted on the second side wall 220 through the mounting structure, eliminating the need for a bracket to fix the BMS400 in the battery box, thereby improving the integrity of the interior of the battery box. In addition, the BMS400, the connecting bar 600, and the connecting wire 500 in this embodiment are all mounted on the expansion beam 200, which not only improves the assembly efficiency of the battery pack, but also improves the assembly accuracy between the BMS400 and the connecting wire 500, and between the connecting bar 600 and the connecting wire 500. Of course, if the height space of the battery box is sufficient, the BMS400 can also be mounted on the top surface of the expansion beam 200 through the mounting structure. In this embodiment, arranging the BMS400 on the second side wall 220 can avoid mutual interference between the BMS400 and the battery cell assembly 100 during installation.

[0040] As shown in Figures 1 to 4, the mounting structure includes a first mounting member 540 and a second mounting member 520. The first mounting member is set on the BMS400, and the second mounting member 520 is set on the second side wall 220. The first mounting member 540 and the second mounting member 520 are detachably connected to install the BMS400 on the expansion beam 200.

[0041] As shown in Figures 1 to 4, the mounting structure also includes a first protrusion 510 and a second protrusion 530. The first protrusion 510 is protruded from the outer wall of the BMS400, and the first mounting member 540 is arranged on the first protrusion 510. The second protrusion 530 is protruded from the second side wall 220, and the second mounting member 520 is arranged on the second protrusion 530 to facilitate the arrangement of the first mounting member 540 and the second mounting member 520.

[0042] As shown in Figures 1 to 4, the first protrusion 510 is provided with a first socket 511, the first mounting member 540 is a bolt passed through the first socket 511, the second protrusion 530 is provided with a second socket 531, the second mounting member 520 is inserted into the second socket 531, and the second mounting member 520 is a rivet nut that cooperates with the bolt thread. When assembling the BMS400 and the expansion beam 200, just screw the bolt into the rivet nut.

[0043] In one embodiment, the second mounting member 520 is a slot provided on the second protrusion 530, and the first mounting member 540 is an insert provided on the first protrusion 510, which is removably inserted into the slot. Of course, in other embodiments, the first mounting member 540 and the second mounting member 520 may also have other removable connection structures, which are not listed here.

[0044] As shown in Figures 1 to 4, a mounting structure is provided on both sides of the BMS400 to improve the reliability of the connection between the BMS400 and the expansion beam 200. Of course, two or even more mounting structures can be provided on both sides of the BMS400. The number of mounting structures can be determined according to the size of the BMS400; or, one or more mounting structures can be provided on both sides of the upper and lower sides of the BMS400, depending on the internal space distribution of the battery box.

[0045] In this embodiment, the expansion beam 200 is an aluminum extruded profile. The aluminum extrusion molding process is a relatively common production process in this field, which is conducive to reducing production costs.

[0046] The battery pack provided in this embodiment is suitable for a traditional battery pack structure (i.e., the battery cell assembly 100 is sandwiched between two end plates to form a battery module, and the battery module is installed in a battery box), and is also suitable for an integrated battery structure in which the battery cell assembly 100 is directly arranged in the battery box (cell to pack (CTP) structure).

Claims

1. Battery pack, including: Battery box; A battery cell assembly (100), wherein the battery cell assembly (100) is arranged in the battery box; An expansion beam (200) is fixed in the battery box, the expansion beam (200) comprises a first side wall (210) and a second side wall (220) which are arranged opposite to each other, and the first side wall (210) is bonded to the battery cell assembly (100).

2. The battery pack according to claim 1, wherein: The second side wall (220) is arranged at an angle, and the angle between the second side wall (220) and the bottom surface of the expansion beam (200) is smaller than the angle between the second side wall (220) and the top surface of the expansion beam (200).

3. The battery pack according to claim 2, wherein: The included angle between the second side wall (220) and the bottom surface of the expansion beam (200) is in the range of 80°-85°.

4. The battery pack according to any one of claims 1 to 3, wherein: The first side wall (210) has a groove (211) opening toward the battery cell assembly (100), and the groove (211) is configured to be filled with adhesive (300).

5. The battery pack according to claim 4, wherein: A glue injection port (212) is provided on the groove wall of the groove (211), and the adhesive (300) can be injected into the groove (211) through the glue injection port (212).

6. The battery pack according to any one of claims 1 to 3, further comprising a connecting bar (600) and a connecting wire (500), at least one of the connecting bar (600) and the connecting wire (500) being fixed on the second side wall (220), or at least one of the connecting bar (600) and the connecting wire (500) being fixed on the top surface of the expansion beam (200).

7. The battery pack according to claim 6, further comprising a fixing member (700), the second side wall (220) or the top surface of the expansion beam (200) is provided with a mounting hole (221), the fixing member (700) is fixed in the mounting hole (221), and at least one of the connecting row (600) and the connecting line (500) is arranged on the fixing member (700).

8. The battery pack according to any one of claims 1 to 3, further comprising a battery management system BMS (400) and a mounting structure, wherein the BMS (400) is mounted on the second side wall (220) or the top surface of the expansion beam (200) through the mounting structure.

9. The battery pack according to claim 8, wherein: The mounting structure comprises a first mounting member (540) and a second mounting member (520), wherein the first mounting member (540) is arranged on the BMS (400), and the second mounting member (520) is arranged on the second side wall (220) or the top surface of the expansion beam (200), and the first mounting member (540) and the second mounting member (520) are detachably connected.

10. The battery pack according to claim 9, wherein: The mounting structure further comprises a first protrusion (510) and a second protrusion (530), wherein the first protrusion (510) is protruded from the outer wall of the BMS (400), and the first mounting member is arranged on the first protrusion (510), and the second protrusion (530) is protruded from the second side wall (220) or the top of the expansion beam (200), and the second mounting member (520) is arranged on the second protrusion (530).

11. The battery pack according to claim 10, wherein: The first protruding portion (510) is provided with a first insertion hole (511), the first mounting member (540) is a bolt, and the first mounting member (540) is inserted into the first insertion hole (511), the second protruding portion (530) is provided with a second insertion hole (531), the second mounting member (520) is inserted into the second insertion hole (531), and the second mounting member (520) is a rivet nut that matches the thread of the bolt.

12. The battery pack according to any one of claims 1 to 3, wherein: A weight reduction cavity (230) is provided between the first side wall (210) and the second side wall (220).

13. The battery pack according to claim 12, wherein: The expansion beam (200) further comprises at least one reinforcing rib (240), wherein the reinforcing rib (240) is disposed in the weight reduction cavity (230), and two ends of the reinforcing rib (240) are respectively fixedly connected to the first side wall (210) and the second side wall (220).

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