Battery pack

Abstract

Disclosed in the present application is a battery pack, comprising a housing, a cell assembly, and reinforcing plates. The reinforcing plates each comprise a foam adhesive layer and a fiberglass cloth layer, wherein the foam adhesive layer is wrapped around the fiberglass cloth layer. The cell assembly is arranged in the housing, one reinforcing plate is arranged on each of two side walls of the cell assembly in the direction of length thereof, and the foam adhesive layers are fitted to the side walls of the cell assembly. On the basis of the law of the lever, the battery pack has the lowest bending and shear resistance in the direction of length of the cell assembly, and mounting the reinforcing plates on both sides of the cell assembly in the direction of length thereof can specifically improve the bending and shear resistance of the battery pack.

Description

A battery pack

[0001] The present application claims priority to the Chinese patent application No. 202422271455.9 filed on September 14, 2024 with the Chinese Patent Office, the whole content of the above application is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of batteries, in particular to a battery pack. BACKGROUND

[0003] With the rapid development of the electric vehicle market, the requirements for battery energy density, safety and reliability are increasing. At present, as the core component of the battery pack of the electric vehicle, the battery pack is usually composed of multiple battery cells in series or parallel. However, although this structure composed of multiple battery cells improves the energy density, it also brings many disadvantages. TECHNICAL PROBLEM

[0004] Firstly, the combination of multiple battery cells makes the battery cell group weak in integrity. Since there are gaps and connecting pieces between the battery cells, these gaps and connecting pieces are prone to become stress concentration areas when the battery pack is subjected to external impact or vibration, resulting in deformation or even fracture of the battery pack. Therefore, the low strength of the battery pack increases the safety risk of the battery pack.

[0005] Secondly, when a new energy vehicle or other battery pack with high battery capacity is needed, the stacking and arrangement of multiple battery cells make the entire battery pack have a large volume. According to the principle of leverage, the bending and shearing resistance of the entire battery pack will be significantly reduced. Especially when used on a new energy vehicle, it often involves a deceleration slope or other bumpy sections, and the battery pack will be subjected to various complex forces from the road surface. If the bending and shearing resistance of the battery pack is insufficient, deformation or damage will easily occur, and even serious consequences such as battery short circuit, fire or explosion will be caused.

[0006] Finally, the insulation of the battery cells in the battery pack is generally treated by a glue pouring process to form a glue pouring layer to wrap the battery cells in an insulation structure. However, the glue pouring layer can only improve the insulation performance of the battery cells and cannot improve the stiffness of the battery pack, so the battery pack still has safety hazards. TECHNICAL SOLUTION

[0007] The present application provides a battery pack, comprising: a shell; a battery cell group arranged in the shell; a reinforcing plate, two side walls of the battery cell group in the length direction are respectively provided with one reinforcing plate, the reinforcing plate comprises a foamed glue layer and a glass cloth layer, and the foamed glue layer wraps the glass cloth layer; wherein the foamed glue layer is arranged in close contact with the side wall of the battery cell group. ADVANTAGEOUS EFFECTS

[0008] The battery pack provided by the application has the beneficial effects that: by adopting the above scheme, based on the principle of lever, the length direction of the battery cell group is the thinnest part of the bending and shearing resistance, the reinforcing plate is installed on both sides of the length direction of the battery cell group, the bending and shearing resistance of the battery pack can be improved, the foamed glue layer and the glass fiber cloth layer are used to form the reinforcing plate, the self-weight and the volume of the foamed glue layer and the glass fiber cloth layer are low, the self-weight of the battery pack is not obviously increased, and the internal space of the shell is not occupied too much, so that the high-density energy storage in the battery pack can be ensured. In addition, the foamed glue layer and the glass fiber cloth layer are good insulating materials, so that the safety of the battery pack is further improved.

[0009] In addition to the above beneficial effects, the reinforcing plate combined by the foamed glue layer and the glass fiber cloth layer has higher convenience, because the battery pack is subjected to glue filling treatment during the production process, the glass fiber cloth layer only needs to be placed in the corresponding position in advance, and then the foamed glue is filled, part of the foamed glue is solidified on the surface of the glass fiber cloth layer to form the foamed glue layer, in the production process, the processing process is reduced, so that the reinforcing plate added in the battery pack does not affect the time required in the normal battery pack processing process. In addition, the glass fiber cloth layer has burrs due to the material, which can pierce the bubbles of the foamed glue, so as to improve the density of the foamed glue, make the foamed glue layer have the trend of solidified glue, and further increase the strength and hardness of the reinforcing plate. BRIEF DESCRIPTION OF DRAWINGS

[0010] Fig. 1 is a schematic diagram of the three-dimensional structure of the application;

[0011] Fig. 2 is a schematic diagram of the explosion structure of the application;

[0012] Fig. 3 is an enlarged view of part A of Fig. 2;

[0013] Fig. 4 is a schematic diagram of the separation state of the battery cell, the reinforcing plate and the liquid cooling plate of the application;

[0014] Fig. 5 is a schematic diagram of the local three-dimensional structure of the battery cell group, the reinforcing plate and the liquid cooling plate of the application;

[0015] Fig. 6 is a schematic diagram of the local top view structure of the battery cell group, the reinforcing plate and the liquid cooling plate of the application.

[0016] Among them, the meaning of the reference signs is as follows: 1, shell; 11, top surface; 111, assembly groove; 12, bottom surface; 121, pressure relief hole group; 2, battery cell group; 21, battery cell; 3, reinforcing plate; 31, protruding structure; 4, liquid cooling plate.

[0017] Embodiment of the application

[0018] Referring to FIG. 1-2, the application discloses a battery pack, comprising a shell 1, a battery cell group 2 and a reinforcing plate 3, the reinforcing plate 3 comprises a foamed glue layer and a glass cloth layer, the foamed glue layer wraps the glass cloth layer, wherein the battery cell group 2 is arranged in the shell 1, and each side wall of the battery cell group 2 in the length direction is provided with a reinforcing plate 3, and the foamed glue layer is arranged on the side wall of the battery cell group 2.

[0019] Specifically, the battery pack comprises a shell 1, a battery cell group 2 and a reinforcing plate 3, the battery cell group 2 is arranged in the shell 1, the reinforcing plate 3 is composed of a foamed glue layer wrapping a glass cloth layer, the foamed glue layer is made of foamed glue, and the glass cloth layer is made of glass cloth. Each side wall of the battery cell group 2 in the length direction is provided with a reinforcing plate 3, and the foamed glue layer is arranged on the side wall of the battery cell group 2. Since the side wall of the battery cell group 2 is the most stress concentrated position, the reinforcing plate 3 is arranged on the side wall of the battery cell group 2, that is, the foamed glue layer is arranged on the side wall of the battery cell group 2, so as to improve the strength of the side wall in the length direction of the battery pack. The above side wall can be the top side wall and the bottom side wall of the battery cell group 2, or the side wall corresponding to the cylindrical surface of the battery cell 21 in the length direction of the battery cell group 2, that is, without affecting the normal arrangement of the pressure relief valve of the battery cell 21 in the battery cell group 2, the reinforcing plate 3 can be arranged on the top side wall and the bottom side wall of the battery cell group 2, or on the side walls of the left and right sides of the battery cell group 2 in the length direction. In addition, the shape of the reinforcing plate 3 can be arranged according to the shape of the side wall of the battery cell group 2, that is, the foamed glue layer and the glass cloth layer can be arranged according to the shape of the side wall of the battery cell group 2.

[0020] The specific processing process of the reinforcing plate 3 can be to spray foamed glue on the outer surface of the glass cloth layer in advance to make the reinforcing plate 3. Alternatively, the glass cloth layer can be arranged on the side wall of the battery cell group 2 in the shell 1, and part of the foamed glue can be solidified on the surface of the glass cloth layer to form a foamed glue layer during the glue filling process of the battery cell group 2. In the production process, the production process is less, so that the addition of the reinforcing plate 3 in the battery pack will not affect the time required in the normal battery pack processing process. In addition, the glass cloth layer has burrs due to material reasons, which can pierce the bubbles of the foamed glue, thereby improving the density of the foamed glue and making the foamed glue layer have the trend of solidified glue, and further increasing the strength and hardness of the reinforcing plate 3.

[0021] In some embodiments, in order to improve the bonding strength of the glass cloth layer and the foamed glue layer, the glass cloth layer has pores and burrs, the burrs penetrate into the foamed glue layer, and the foamed glue layer penetrates into the pores.

[0022] Specifically, due to the material characteristics of the fiberglass cloth layer, which includes pores and burrs, combined with the burrs penetrating the foam layer and the foam layer penetrating the pores, the contact area between the fiberglass cloth layer and the foam layer is greatly increased, thereby effectively improving the bonding strength between them. Optionally, based on the structural characteristics of the fiberglass cloth layer, during the processing of the reinforcing plate 3, the fiberglass cloth constituting the fiberglass cloth layer can be fixed in the mold used to process the reinforcing plate 3, and then the foam layer constituting the foam adhesive can be injected into the mold. Because the fiberglass cloth layer has pores and burrs, the foam adhesive will flow into the pores of the fiberglass cloth layer. Correspondingly, the burrs of the foam adhesive will also puncture the air bubbles in the foam adhesive, promoting an increase in the density of the foam adhesive constituting the foam layer, making the foam adhesive layer tend to solidify like glue, thereby significantly improving the strength and hardness of the foam adhesive layer.

[0023] In some embodiments, the number of cells 21 is increased to increase the energy storage of the battery pack. The cell group 2 includes a plurality of cells 21, which are arranged in N columns. There are (N-1) columns of gaps between the N columns of cells 21. A reinforcing plate 3 is provided in at least one column of gaps, and the foam adhesive layer of the reinforcing plate 3 is bonded to the adjacent cells 21.

[0024] Specifically, the battery cell group 2 consists of multiple battery cells 21, which are arranged in N columns. The N columns of battery cells 21 form a gap of (N-1) columns. According to the strength and insulation requirements, a reinforcing plate 3 can be set in one or more columns of gaps. Correspondingly, the foam layer of the reinforcing plate 3 is attached to the side wall of the adjacent battery cell 21.

[0025] In some embodiments, to prevent the battery pack from overheating and affecting its use, the battery pack further includes a liquid cooling plate 4, wherein the liquid cooling plate 4 is disposed in at least one row of gaps, and the liquid cooling plate 4 and the reinforcing plate 3 can be disposed in the gaps selectively. When the heat dissipation requirement is high, more liquid cooling plates 4 can be disposed. When the heat dissipation requirement is met, reinforcing plates 3 can be selectively disposed in other gaps so that the battery pack can simultaneously meet the heat dissipation requirement, the strength requirement and the insulation requirement.

[0026] Referring to FIG4, in some embodiments, when the battery cell 21 is a cylindrical battery cell, the foam layer of the reinforcing plate 3 and the liquid cooling plate 4 are both provided with a protruding structure 31 facing the battery cell 21. The protruding structure 31 extends between two adjacent cylindrical battery cells in the same row, and the protruding structure 31 is in contact with the cylindrical surface of the cylindrical battery cell.

[0027] Specifically, the protruding structure 31 is provided on the side wall of the cylindrical cell to increase the contact area between the liquid cooling plate 4 and the cell 21, thereby improving heat dissipation performance, and to increase the contact area between the reinforcing plate 3 and the cell 21, thereby improving the strength and insulation performance of the battery pack.

[0028] It should be noted that Fig. 4 increases the gap between the reinforcing plate 3, the liquid cooling plate 4 and the cylindrical battery cell in order to show the relationship between the protruding structure 31 shape and the cylindrical battery cell, which is actually in a fitted state.

[0029] Referring to Figs. 5 and 6, on the basis of the cylindrical battery cell of the battery cell 21, in order to improve the density of the battery cell 21 of the battery pack, the two adjacent rows of battery cells 21 are arranged in a staggered manner, and the gap is arranged in a serpentine shape as the battery cell 21 is arranged in a staggered manner. Correspondingly, the reinforcing plate 3 and the liquid cooling plate 4 are arranged in a serpentine shape corresponding to the serpentine gap, that is, the foam layer and the fiberglass cloth layer of the reinforcing plate 3 are arranged in a serpentine shape corresponding to the serpentine gap, so that the foam layer, the fiberglass cloth layer and the liquid cooling plate 4 can be arranged in the serpentine gap, thereby minimizing the gap between the battery cells 21, ensuring the proper density of the battery cells 21 of the battery pack, and also ensuring the contact area of the foam layer and the battery cell 21, and the contact area of the liquid cooling plate 4 and the battery cell 21, thereby ensuring the heat dissipation performance of the liquid cooling plate 4, and ensuring the strength performance and insulation performance of the reinforcing plate 3.

[0030] In some embodiments, in order to ensure uniform heat dissipation of the battery cell group 2, the following setting relationship is arranged in the gap of N-1 rows: the gaps of the two adjacent rows, one gap is equipped with a liquid cooling plate 4, and the other gap is equipped with a reinforcing plate 3, that is, the liquid cooling plate 4 and the reinforcing plate 3 are arranged in a staggered manner, which ensures uniform heat dissipation of the battery cell group 2, and also enables uniform arrangement of the reinforcing plate 3, thereby improving the rigidity and safety of the battery pack.

[0031] In addition, in some battery packs, a single-sided liquid cooling plate 4 is used in the setting mode, and in this setting mode of the battery pack, only the reinforcing plate 3 needs to be arranged in the gap where the liquid cooling plate 4 is not arranged, thereby ensuring that the reinforcing plate 3 is arranged in a staggered manner without affecting the single-sided liquid cooling plate 4 setting mode, thereby enhancing the rigidity and safety of the battery pack.

[0032] In some embodiments, in order to ensure the safety of the battery, a pressure relief valve is arranged in the battery cell group 2, and when the battery cell group 2 is composed of multiple battery cells 21, the pressure relief valve of each battery cell 21 is directed in the same direction, thereby facilitating the drainage of the heat runaway substances that may be generated by the multiple battery cells 21. The direction of the pressure relief valve is the bottom surface 12 of the shell 1, that is, the bottom side wall of the battery cell group 2, and the side of the top surface 11 of the shell 1 opposite to the bottom surface 12 is provided with the reinforcing plate 3, and / or the side of the top surface 11 away from the battery cell group 2 is provided with the reinforcing plate 3. Correspondingly, in order to facilitate the arrangement of the pressure relief valve of the multiple battery cells 21 in the battery cell group 2, the reinforcing plate 3 is not arranged in the direction of the pressure relief valve of the battery cell 21.

[0033] Specifically, the reinforcing plate 3 can be arranged on the top surface 11 of the shell 1 towards the side of the battery cell group 2, or arranged on the top surface 11 of the shell 1 away from the side of the battery cell group 2, or arranged on both sides. In this way, the strength of the top surface 11 of the battery cell group 2 is enhanced, thereby increasing the safety of the battery pack during use, transportation, and stacking storage. That is, during use, transportation, and stacking storage, the foamed glue layer can provide better energy absorption effect, the combination of the glass cloth layer and the foamed glue layer also provides a certain bending strength for the top of the entire battery pack, thereby achieving the effect of increasing the safety of the battery pack.

[0034] Referring to FIG. 3, based on the structure of arranging the reinforcing plate 3 on the top surface 11 of the shell 1 away from the side of the battery cell group 2, the top surface 11 of the shell 1 is provided with an assembly groove 111, and the reinforcing plate 3 is arranged in the assembly groove 111 and flush with the surrounding surface of the top surface 11 of the shell 1. In this way, the installation of the reinforcing plate 3 is facilitated, and the foamed glue layer of the reinforcing plate 3 is flush with the outer surface of the top surface 11 of the shell 1. After the reinforcing plate 3 is assembled into the assembly groove 111, the integrity of the shell 1 can still be maintained.

[0035] In some embodiments, the glass cloth layer in the reinforcing plate 3 is preferably provided with three layers, and the structure of the three layers of glass cloth layer forms a more solid “skeleton”, which can enhance the mechanical strength and rigidity of the reinforcing plate 3. This helps to reduce deformation of the battery pack when subjected to external impact, vibration or pressure, and also improves the stability of the overall structure of the battery pack and reduces the risk of damage to the battery pack due to external force.

[0036] In some embodiments, in order to improve the safety of the battery pack, the bottom surface 12 of the shell 1 is provided with a pressure relief through hole group 121 corresponding to the battery cell group 2, i.e. a pressure relief valve corresponding to the battery cell group 2 is provided for the pressure relief through hole group 121, so that the thermal runaway substances possibly generated by the battery cell group 2 are discharged to the outside of the battery pack through the pressure relief through hole group 121, thereby improving the safety of the battery pack.

Claims

1. A battery pack, comprising: a shell (1); a cell group (2) arranged in the shell (1); a reinforcing plate (3) arranged on both side walls of the cell group (2) in the length direction, the reinforcing plate (3) comprising a foamed adhesive layer and a fiberglass cloth layer, the foamed adhesive layer wrapping the fiberglass cloth layer; wherein the foamed adhesive layer is arranged on the side wall of the cell group (2).

2. The battery pack of claim 1, wherein, The fiberglass cloth layer has apertures and burrs, the burrs penetrating into the foamed adhesive layer, and the foamed adhesive layer penetrating into the apertures.

3. The battery pack of claim 1, wherein, The cell group (2) comprises a plurality of cells (21), the plurality of cells (21) being arranged in N columns, and (N-1) column gaps being arranged between the N column cells (21), wherein at least one column gap is provided with the reinforcing plate (3), and the foamed adhesive layer of the reinforcing plate (3) is attached to the adjacent cell (21).

4. The battery pack of claim 3, wherein, Further comprising a liquid cooling plate (4) arranged in at least one column gap.

5. The battery pack of claim 4, wherein, The cell (21) is a cylindrical cell, the foamed adhesive layer of the reinforcing plate (3) and the liquid cooling plate (4) are both provided with a protruding structure (31) facing the cell (21), the protruding structure (31) extends between two adjacent cells in the same column, and the protruding structure (31) is attached to the cylindrical surface of the cell.

6. The battery pack of claim 4, wherein, The two adjacent columns of cells (21) are arranged in a staggered manner, the gap is in a serpentine shape, and the foamed adhesive layer, the fiberglass cloth layer and the liquid cooling plate (4) are all curved along the shape of the serpentine gap.

7. The battery pack of claim 4, wherein, In the two adjacent column gaps, one column gap is provided with the liquid cooling plate (4), and the other column gap is provided with the reinforcing plate (3).

8. The battery pack of claim 1, wherein, The cell group (2) has a pressure relief valve, the bottom surface (12) of the pressure relief valve faces the shell (1), the top surface (11) opposite to the bottom surface (12) of the shell (1) is provided with the reinforcing plate (3) on one side facing the cell group (2), and / or the top surface (11) is provided with the reinforcing plate (3) on the side away from the cell group (2).

9. The battery pack of claim 8, wherein, The top surface (11) of the shell (1) is provided with an assembly groove (111), the reinforcing plate (3) is arranged in the assembly groove (111), and when the reinforcing plate (3) is located on the side of the top surface (11) away from the cell group (2), the foamed adhesive layer of the reinforcing plate (3) is flush with the outer surface of the top surface (11) of the shell (1).

10. The battery pack of any one of claims 1-9, wherein, The fiberglass cloth layer has three layers.

11. The battery pack of claim 1, wherein, The bottom surface (12) of the shell (1) is provided with a pressure relief through hole group (121) corresponding to the cell group (2).

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