Battery module, battery module assembling method, and power battery pack

Abstract

Disclosed in the present application are a battery module, a battery module assembling method, and a power battery pack. The battery module comprises a plurality of battery cell groups arranged side by side in the thickness direction, wherein each battery cell group comprises at least two battery cells and at least one busbar, a plurality of battery cells in each battery cell group are arranged in rows in the length direction, and the positive and negative electrodes of two adjacent battery cells in each battery cell group are arranged opposite each other and are electrically connected by means of the busbar; and the busbar comprises a first connecting end and a second connecting end, one face of the busbar is a pole connecting face, the pole connecting face on the first connecting end comes into contact with and is electrically connected to an end face of a positive pole of one battery cell, the pole connecting face on the second connecting end comes into contact with and is electrically connected to an end face of a negative pole of another battery cell, and the electrically connected end face of the positive pole in each battery cell group is parallel to the electrically connected end face of the negative pole.

Description

Battery module, battery module assembly method, and power battery pack

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on June 15, 2023, with application number 202310710769.1, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, for example, to a battery module, a battery module assembly method and a power battery pack. Background Art

[0003] With the development of new energy vehicles, traditional fuel-powered vehicles are gradually being replaced. Pure electric vehicles, which rely on fuel and are clean and pollution-free, are becoming increasingly popular. As the primary power source for new energy vehicles, the battery's range, safety, and service life are key considerations in its development. As demand for the range of new energy vehicles increases, the battery pack requires more cells, leading to the emergence of matrix battery packs.

[0004] The utilization rate of the internal space of the power battery pack has a great impact on the overall power. In the matrix power battery pack, the connection structure between adjacent battery cells in the battery module is complex and there are many components, resulting in low utilization rate of the internal space of the battery pack, low energy density of the battery pack, and the overall endurance needs to be improved.

[0005] Summary of the Invention

[0006] The present application provides a battery module, which includes a plurality of cell groups arranged side by side in the thickness direction, the cell groups including at least two cell groups and at least one bus bar, the plurality of cell groups in each cell group are arranged in a row along the length direction thereof, and the positive and negative poles of two adjacent cell groups in each cell group are arranged relative to each other and electrically connected through the bus bar; the bus bar includes a first connection end and a second connection end, one side of the bus bar is a pole connection surface, the pole connection surface on the first connection end contacts and is electrically connected to the end face of the positive pole of one cell, the pole connection surface on the second connection end contacts and is electrically connected to the end face of the negative pole of another cell, and the end face of the electrically connected positive pole and negative pole in each cell group are parallel.

[0007] In one embodiment, the busbar is a bendable sheet structure.

[0008] In one embodiment, the bending portion of the busbar is located in the middle of the length direction of the busbar, and adjacent positive poles and negative poles in the same battery cell group are arranged opposite to each other.

[0009] In one embodiment, the extending direction of the bent portion of the busbar is the thickness direction of the battery cell.

[0010] In one embodiment, the bending portion of the busbar does not exceed the edge of the battery cell.

[0011] In one embodiment, the back side of the pole connection surface is a welding surface, and the busbar is connected to the pole by welding.

[0012] In one embodiment, the positive electrode column and the negative electrode column on each battery cell are respectively arranged at two ends in the length direction of the battery cell.

[0013] The present application also provides a battery module assembly method, which is applied to the above-mentioned battery module. Before the busbar and the battery cell are connected, the angle between the first connection end and the second connection end is greater than 0°. The battery module assembly method includes: welding the first connection end to the positive electrode column and welding the second connection end to the negative electrode column; bending the busbar, so that the first connection end and the second connection end are parallel after bending, and the battery cells in each battery cell group are arranged along the length direction; and arranging multiple battery cell groups along the thickness direction.

[0014] The present application also provides a power battery pack, which includes a shell and the above-mentioned battery module, wherein the battery module is arranged inside the shell, and a connecting plate is provided on the top of the battery module, and each battery cell is connected to the connecting plate.

[0015] In one embodiment, the length of each battery cell ranges from 350 mm to 1000 mm, the total length of the battery module L0 / the length of the internal space of the shell W2 = 0.85 to 0.98, and / or the main body length of the battery module L1 / the overall length of the power battery pack W1 = 0.88 to 0.97. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a schematic structural diagram of a battery cell assembly during welding provided in Example 1 of the present application;

[0017] FIG2 is a schematic structural diagram of a battery cell assembly provided in Example 1 of the present application after assembly;

[0018] FIG3 is a schematic diagram of a partial structure of a battery cell assembly after assembly provided in Example 1 of the present application;

[0019] FIG4 is a schematic diagram of an exploded structure of a power battery pack provided in Example 1 of the present application;

[0020] FIG5 is a top view of a partial structure of a power battery pack provided in Example 1 of the present application;

[0021] FIG6 is a schematic structural diagram of a battery cell assembly during welding provided in Example 2 of the present application;

[0022] FIG7 is a schematic structural diagram of a battery cell assembly after assembly provided in Example 2 of the present application.

[0023] In the figure: 100, battery cell group; 101, battery cell; 110, positive electrode column; 120, negative electrode column; 130, explosion-proof valve; 140, busbar; 200, battery module; 300, shell; 310, bottom plate; 320, cover plate; 330, enclosure; 400, connecting plate; 500, battery management system; 600, battery pack circuit breaker unit; 700, liquid cooling plate; 800, welding equipment. DETAILED DESCRIPTION

[0024] The technical solution of the present application will be described below in conjunction with the accompanying drawings, and the described embodiments are part of the embodiments of the present application.

[0025] In the description of this application, the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting this application. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0026] In the description of this application, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they can refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. A person of ordinary skill in the art will understand the meaning of these terms in this application in a variety of contexts.

[0027] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0028] Example 1

[0029] 1 and 2 , this embodiment provides a battery module 200 comprising a plurality of cell groups 100 arranged side by side in a thickness direction. The cell groups 100 include at least two cells 101 and at least one bus bar 140. The plurality of cells 101 in each cell group 100 are arranged in a row along its length, and the positive and negative electrodes of two adjacent cells 101 in each cell group 100 are arranged opposite each other and electrically connected via the bus bar 140. The bus bar 140 includes a first connection end and a second connection end. One side of the bus bar 140 is a pole connection surface. The pole connection surface on the first connection end contacts and electrically connects to the end face of the positive electrode 110 of one cell 101, and the pole connection surface on the second connection end contacts and electrically connects to the end face of the negative electrode 120 of another cell 101. The end faces of the electrically connected positive electrode 110 and negative electrode 120 in each cell group 100 are parallel.

[0030] The battery module 200 electrically connects the multiple battery cells 101 in each battery cell group 100 through the bus 140. In terms of the arrangement of the battery cells 101, the multiple battery cells 101 in each battery cell group 100 are connected end to end along their length, and the positive electrode column 110 and the negative electrode column 120 are opposite to each other, so as to facilitate connection and conduction with the bus 140. The multiple battery cell groups 100 are arranged side by side, so that the multiple battery cells 101 in the battery module 200 can be compactly arranged in both the length direction and the height direction. Adjacent battery cells 101 can be electrically connected through only one bus 140, which is convenient to connect and can effectively save the internal space of the power battery pack, so that the power battery pack has a higher energy density, thereby greatly improving the endurance of the power battery pack.

[0031] In one embodiment, a gap is provided between adjacent cell groups 100, satisfying the requirement of gap ≥ 0.1 mm and ≥ 0.2 times the thickness of the cell 101. Heat insulation strips are provided between adjacent cell groups 100, with a thickness no greater than the gap.

[0032] Continuing with Figures 1 and 2 , the busbar 140 is a bendable sheet-like structure. In this embodiment, before the busbar 140 is connected to the pole, the first and second connection ends are not parallel, that is, there is a certain angle between the first and second connection ends. This angle facilitates the connection between the pole and the busbar 140.

[0033] For example, the busbar 140 and the pole are electrically connected by welding. The back of the pole connection surface can be used as a welding surface. The welding device 800 contacts this surface to fix the busbar 140 on the pole. Therefore, when welding, the welding device 800 can be placed between the angles of the first connection end and the second connection end, which is very convenient to operate. After welding is completed, the busbar 140 is bent until the first connection end and the second connection end are parallel, so that the two connected battery cells 101 are parallel, avoiding waste of the internal space of the power battery pack. The busbar 140 is set to a sheet structure, which can be bent very conveniently.

[0034] The busbar 140 should not be too thin to avoid damage during bending or insufficient conductivity. Of course, the busbar 140 should not be too thick to avoid difficulty in bending, inconvenience in assembly, and waste of space inside the power battery pack.

[0035] After the busbar 140 is bent until the first connection end and the second connection end are parallel, the distance between two adjacent battery cells 101 is 4-40 mm. If the distance is too small, they cannot be grouped, and if it is too large, the power of the entire package will be affected.

[0036] After the busbar 140 is bent until the first connection end and the second connection end are parallel to each other, the interval between the first connection end and the second connection end is 0.2-20 mm.

[0037] In one embodiment, the busbar 140 can be made of copper, aluminum, or other metal materials according to usage requirements.

[0038] In one embodiment, before the busbar 140 is bent, the angle between the first connection end and the second connection end is greater than or equal to 60°, ensuring that the welding device 800 can perform welding from the end face of the pole.

[0039] In one embodiment, the bend of the busbar 140 is located in the middle of its length, and adjacent positive and negative electrodes 110 and 120 within the same battery cell assembly 100 are positioned opposite each other. The busbar 140's bend is located in the middle, creating a symmetrical structure that aligns the ends after bending. This structure facilitates the positioning and installation of the busbar 140 and the battery cells 101, preventing height misalignment between the two assembled battery cells 101, which could affect subsequent assembly and waste space.

[0040] In one embodiment, positioning notches can be provided on the sides of the busbar 140 to align with the terminals, thereby ensuring that the opposing end faces of the two battery cells 101 face each other after assembly. Alternatively, during assembly, the end of the first connection terminal is aligned with the edge of the positive terminal 110, while the end of the second connection terminal is aligned with the edge of the negative terminal 120, thereby ensuring that the opposing end faces of the two battery cells 101 face each other after assembly.

[0041] In one embodiment, referring to Figures 2 and 3 , the bend of the busbar 140 extends in the thickness direction of the battery cell 101. In the design of the battery cell 101 structure, a certain gap exists between the upper edge of the pole and the upper end surface of the battery cell 101. In one embodiment, the gap is 2 to 30 mm. This gap reserves space for the bend of the busbar 140. Therefore, the placement of the busbar 140 in this manner facilitates the overall structural layout and makes it easier to ensure that the bend of the busbar 140 does not extend beyond the edge of the battery cell 101.

[0042] In this embodiment, the bending part of the busbar 140 does not exceed the edge of the battery cell 101. The reason is that when the height of the bending part of the busbar 140 is higher than the height of the battery cell 101, the busbar 140 protrudes from the upper end surface of the battery cell 101, which will affect the assembly of other components above the battery cell 101 and will occupy a larger space inside the power battery pack, which is not conducive to improving the battery energy density.

[0043] In one embodiment, the positive electrode post 110 and the negative electrode post 120 of each battery cell 101 are located at either end of the battery cell 101's length. Each pair of battery cells 101 is connected by a single busbar 140. An explosion-proof valve 130 is installed at the end of the battery cell 101 not connected to the busbar 140 to release internal pressure and prevent explosions and other dangerous accidents in the battery module 200 under high temperature and high pressure conditions.

[0044] This embodiment also provides a method for assembling a battery module 200, which is applicable to the above-mentioned battery module 200. Before the busbar 140 and the battery cell 101 are connected, the angle between the first connection end and the second connection end is greater than 0°. As described above, the setting of this angle facilitates welding of the busbar 140 and the terminal. The assembly method of the battery module 200 mainly includes:

[0045] S1. Welding the first connection end to the positive electrode column 110 and the second connection end to the negative electrode column 120.

[0046] S2. Bend the busbar 140 so that the first connection end and the second connection end are parallel to each other, and the battery cells 101 in each battery cell group 100 are arranged along the length direction.

[0047] S3. Arrange the plurality of battery cell groups 100 along the thickness direction.

[0048] Welding is a mature technology in the field, providing reliable assembly and high connection strength. During the assembly of the battery cell pack 100, a large number of parts are not required, making assembly convenient and highly efficient. Furthermore, the assembled battery module 200 has a compact overall structure, which helps improve the battery life of the power battery pack.

[0049] 4 , this embodiment further provides a power battery pack, which includes a housing 300 and the aforementioned battery module 200 . The battery module 200 is disposed inside the housing 300 .

[0050] Since the power battery pack adopts the above-mentioned compact battery module 200, the overall spatial layout is more reasonable, and the capacity density is fully improved within a limited assembly space.

[0051] In one embodiment, the housing 300 includes a panel 330, a top cover connected to the top of the panel 330, and a bottom plate 310 connected to the bottom of the panel 330. The battery cells 101 are attached to the bottom plate 310, which is provided with vertical reinforcing ribs parallel to the battery cells 101. The ribs and the projection of the explosion-proof valve 130 at the height of the battery cells 101 do not overlap.

[0052] In one embodiment, the housing 300 further includes a battery management system 500, a battery pack disconnect unit 600, and a liquid cooling plate 700. The liquid cooling plate 700 is positioned at the bottom of the battery module 200 to dissipate heat from the battery module 200. In one embodiment, the liquid cooling plate 700 and the bottom of the battery module 200 can be secured by gluing using a thermally conductive structural adhesive with a thermal conductivity of no greater than 5 W / (m·k), with the adhesive area accounting for 60% to 100% of the total area of ​​the liquid cooling plate 700. There can be one or more liquid cooling plates 700, depending on the intended use.

[0053] In one embodiment, a connecting plate 400 is provided at the top of the battery module 200, and each battery cell 101 is connected to the connecting plate 400. In this embodiment, each battery cell group 100 includes two battery cells 101, and the tops of both battery cells 101 are connected to the connecting plate 400, which can be connected by gluing. The connecting plate 400 spans the left and right battery cells 101, effectively improving the rigidity between the two rows of battery cells 101 and ensuring the structural stability of the power battery pack.

[0054] Referring to Figure 5, in this embodiment, the length range of each battery cell 101 (including the poles at both ends) is 350mm~1000mm, the total length of the battery module L0 / the length of the internal space of the shell W2=0.85~0.98, and the length of the battery module body (excluding the poles) L1 / the overall length of the power battery pack W1=0.88~0.97.

[0055] Example 2

[0056] 6 and 7 , the similarities between the battery module provided in this embodiment and the first embodiment are not described in detail. Only the differences between this embodiment and the first embodiment are described below.

[0057] In this embodiment, the bent portion of the busbar 140 extends in the height direction of the battery cell 101. After being bent, the edge of the busbar 140 does not extend beyond the surface of the battery cell 101 to avoid affecting the arrangement of the multiple battery cell groups 100.

Claims

1. A battery module, comprising a plurality of battery cell groups (100) arranged side by side in a thickness direction, the battery cell groups (100) comprising at least two battery cells (101) and at least one bus bar (140), the plurality of battery cells (101) in each battery cell group (100) being arranged in a row along the length direction of the plurality of battery cells (101), and the positive and negative electrodes of two adjacent battery cells (101) in each battery cell group (100) being arranged opposite to each other and electrically connected via the bus bar (140); The busbar (140) comprises a first connection end and a second connection end, one side of the busbar (140) is a pole connection surface, the pole connection surface on the first connection end contacts and is electrically connected to the end surface of a positive pole (110) of a battery cell (101), the pole connection surface on the second connection end contacts and is electrically connected to the end surface of a negative pole (120) of another battery cell (101), and the end surface of the electrically connected positive pole (110) and the end surface of the negative pole (120) in each battery cell group (100) are parallel.

2. The battery module according to claim 1, in, The busbar (140) is a bendable sheet-like structure.

3. The battery module according to claim 2, in, The bending portion of the busbar (140) is located in the middle of the length direction of the busbar (140), and adjacent positive poles (110) and negative poles (120) in the same battery cell group (100) are arranged opposite to each other.

4. The battery module according to claim 2, in, The extending direction of the bent portion of the busbar (140) is the thickness direction or height direction of the battery cell (101).

5. The battery module according to claim 2, in, The bending part of the busbar (140) does not exceed the edge of the battery core (101).

6. The battery module according to any one of claims 1 to 5, in, The back side of the pole connection surface is a welding surface, and the busbar (140) is connected to the pole by welding.

7. The battery module according to any one of claims 1 to 5, in, The positive electrode column (110) and the negative electrode column (120) on each battery cell (101) are respectively arranged at two ends in the length direction of the battery cell (101).

8. A battery module assembly method, applied to the battery module of claims 1-7, wherein before the busbar is connected to the battery cell, the angle between the first connection end and the second connection end is greater than 0°, and the battery module assembly method include: Welding the first connection end to the positive electrode column, and welding the second connection end to the negative electrode column (120); The busbar is bent so that the first connection end and the second connection end are parallel to each other and the cells in each cell group are arranged along the length direction; Arrange multiple battery cell groups along the thickness direction.

9. A power battery pack, comprising a shell (300) and a battery module (200) according to any one of claims 1 to 7, wherein the battery module (200) is arranged inside the shell (300), and a connecting plate (400) is arranged on the top of the battery module (200), and each battery cell (101) is connected to the connecting plate (400).

10. The power battery pack according to claim 9, in, The length of each battery cell (101) ranges from 350 mm to 1000 mm, and satisfies at least one of the following conditions: Total length of battery module L0 / length of inner space of shell W2=0.85~0.98; Battery module main body length L1 / power battery pack overall length W1=0.88~0.97.

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