Electric connector between battery cells, battery module, battery pack and electric automobile

Abstract

The utility model discloses an electric connecting piece between battery cells, a battery module, a battery pack and an electric automobile, the electric connecting piece between the battery cells comprises a connecting piece body, and the connecting piece body is of a double-layer structure formed by folding and attaching a whole piece front and back and is provided with an upper layer plate and a lower layer plate; the left part and the right part of the lower-layer plate are respectively provided with a battery cell pole welding area, and the left part and the right part of the upper-layer plate are respectively provided with an arc-shaped avoiding gap for avoiding the battery cell pole welding area; battery cell observation holes are formed in the two battery cell pole welding areas of the lower layer plate, two anti-expansion holes are formed between the two battery cell pole welding areas of the lower layer plate, and the two anti-expansion holes are close to the two battery cell pole welding areas respectively. According to the utility model, the pulling of the battery core pole in the expansion process of the battery core can be effectively avoided, the failure risk of the battery core is avoided, and the safety is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric vehicle batteries, and particularly relates to an electrical connector between battery cells, a battery module, a battery pack and an electric vehicle. Background Art

[0002] The electric vehicle industry has developed rapidly, and currently people focus on the reliability and usability of the power section of electric vehicles. A battery pack is composed of one or more battery modules, and the battery modules are formed by stacking and connecting single cells, thus forming the core power source of the electric vehicle. During long-term cycling and long-term use, the single cells will expand under the action of electrochemistry. Each single cell is laser welded through an electrical connector between battery cells (mainly an aluminum bar) to form a high-voltage circuit. After the cells expand, the housing is stressed. When the stress is greater than the limit that the cell itself can bear, the cell pole on the cell cover will be pulled off, resulting in failure and further power interruption. Therefore, considering the safety, reliability of the battery pack and the service life of the electric vehicle, the structure of the electrical connector between battery cells for high-voltage connection needs to be optimized in design to avoid the risk of stress failure after the cells expand in advance.

[0003] CN116683124A discloses a battery busbar structure and a process method based on a double-row module. The structure includes a busbar for connecting double-row modules. A folding part extends outward from the middle of the side of the busbar. The folding part matches the width of the busbar. Two sinking platforms for connecting cell poles are recessed on the module connection surface of the busbar. Each sinking platform corresponds to the cell pole of one module. The folding part bends along the side of the busbar and closely adheres to the module connection surface of the busbar. After bending, the folding part and the middle of the busbar together form a double-layer busbar channel. It can enhance the current-carrying capacity of the busbar by means of local folding in a limited space. However, it still has the following problems: (1) Only relying on the middle arch to buffer the stress and impact generated by cell expansion, the buffering effect is insufficient and the safety is not high; (2) Only folding and thickening at the middle connection position, the current-carrying capacity is limited, and the heat dissipation effect is also not good, and the safety is not high. Summary of the Utility Model

[0004] The purpose of the utility model is to provide an electrical connector between battery cells, a battery module, a battery pack and an electric vehicle, so as to effectively avoid the pulling of the cell poles during the cell expansion process, avoid the risk of cell failure and improve the safety.

[0005] In a first aspect, the present utility model provides an electrical connection member between battery cells, which includes a connection member body. The connection member body is a double-layer structure formed by folding a whole piece back and forth, having an upper layer plate and a lower layer plate. The left and right parts of the lower layer plate both have battery cell pole welding areas, and the left and right parts of the upper layer plate are both provided with arc-shaped avoidance notches for avoiding the battery cell pole welding areas. Battery cell observation holes are opened in both battery cell pole welding areas of the lower layer plate, and two anti-expansion holes are opened between the two battery cell pole welding areas of the lower layer plate, and the two anti-expansion holes are respectively close to the two battery cell pole welding areas. The arc-shaped avoidance notch is used to ensure that the battery cell pole welding area is single-layer and the thickness meets the welding requirements. The battery cell observation hole is used to observe whether the lower layer plate is aligned with the battery cell pole to ensure subsequent welding.

[0006] Preferably, the anti-expansion hole is an arc-shaped hole, and the anti-expansion hole bends towards the battery cell pole welding area. The arc-shaped hole can not only effectively prevent expansion and pulling, but also ensure the strength of the connection member body without affecting current carrying.

[0007] Preferably, the radial width range of the anti-expansion hole is: 1.5 mm to 2.5 mm. This size design of the anti-expansion hole not only effectively prevents expansion and pulling, but also ensures the strength of the connection member body, does not affect the structural strength of the connection member body under static conditions, and does not affect current carrying.

[0008] Preferably, the radial distance between the inner edge of the anti-expansion hole and the edge of the battery cell pole welding point is greater than or equal to 11 mm. The opening position of the anti-expansion hole well avoids the welding of the battery cell pole and does not affect the welding quality of the battery cell pole.

[0009] Preferably, the arc-shaped contour of the arc-shaped avoidance notch is conformable to a part of the contour of the battery cell pole welding point, and the radial distance between the arc-shaped contour of the arc-shaped avoidance notch and the edge of the battery cell pole welding point is greater than or equal to 11 mm. The design that the arc-shaped avoidance notch is conformable to a part of the contour of the battery cell pole welding point and the distance is appropriate well avoids the welding of the battery cell pole, does not affect the welding quality of the battery cell pole, and has a limited impact on the current carrying capacity.

[0010] Preferably, a U-shaped buffer groove is punched at the position of the connection member body corresponding to the gap between two adjacent single battery cells. The buffer groove can also effectively buffer the pulling stress generated by the expansion of the battery cell on the connection member body.

[0011] Preferably, the depth d of the buffer groove satisfies: d≤h+ts; wherein h represents the height of the battery pole, t represents the thickness of the lower plate (corresponding to the thickness of the welding area of ​​the battery pole), and s represents the safety gap, s=0.5mm. The deeper the buffer groove is sunken downward, the more effective it is in alleviating the expansion force. However, due to the influence of the height of the battery pole and the welding area of ​​the battery pole, the maximum value of the depth d of the buffer groove is equal to h+ts.

[0012] In a second aspect, the utility model provides a battery module, which includes a plurality of single battery cells, and two adjacent single battery cells are connected by the above-mentioned inter-battery cell electrical connector.

[0013] In a third aspect, the utility model provides a battery pack, which includes the above-mentioned battery module.

[0014] In a fourth aspect, the utility model provides an electric vehicle comprising the above-mentioned battery pack.

[0015] Compared with the prior art, the utility model has the following effects:

[0016] (1) The connector body is a double-layer structure formed by folding the whole piece front and back and pasting it together. The upper plate has an arc-shaped avoidance gap to avoid the two battery cell pole welding areas. The two battery cell pole welding areas of the lower plate are welded to the poles of the two adjacent single cells. Most of the area of ​​the connector body is a double-layer structure, which effectively increases the current carrying capacity and heat dissipation capacity, and is safer.

[0017] (2) Two anti-expansion holes are opened between the two battery cell pole welding areas of the lower plate. Combined with the double-layer structure, it effectively avoids the pulling of the battery cell poles during the battery cell expansion process, prevents the battery cell top cover from being pulled off and failing, avoids the risk of battery cell failure, and improves safety.

[0018] (3) Through the whole piece folding and bonding process and the anti-expansion hole design, the problem of battery cell failure caused by battery cell expansion force is solved while keeping the material and process costs basically unchanged, which is suitable for popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the electrical connector between battery cells in an embodiment of the utility model.

[0020] Figure 2 It is a front view of the electrical connector between battery cells in an embodiment of the utility model.

[0021] Figure 3 It is a rear view of the electrical connector between battery cells in the embodiment of the utility model. DETAILED DESCRIPTION

[0022] In order to understand the features and technical content of the embodiments of the present utility model in more detail, the implementation of the embodiments of the present utility model will be described in detail below with reference to the accompanying drawings. The attached drawings are only for reference and explanation, and are not used to limit the embodiments of the present utility model.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present utility model belongs. The terms used herein are only for the purpose of describing the embodiments of the present utility model and are not intended to limit the present utility model.

[0024] In the following description, reference is made to "some embodiments", which describe a subset of all possible embodiments. However, it can be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict.

[0025] As Figures 1 to 3 shown, the electrical connection member between battery cells in the embodiment of the present utility model includes a connection member body 1. The connection member body 1 is a double-layer structure formed by folding a single-layer board back and forth. The connection member body 1 has an upper layer board 11 and a lower layer board 12. The left and right parts of the lower layer board 12 both have battery cell pole welding areas. The left and right parts of the upper layer board 11 are both provided with arc-shaped avoidance notches 13 for avoiding the battery cell pole welding areas. Battery cell observation holes 14 are provided in both battery cell pole welding areas of the lower layer board 12. Two anti-expansion holes 15 are provided between the two battery cell pole welding areas of the lower layer board 12, and the two anti-expansion holes 15 are respectively close to the two battery cell pole welding areas.

[0026] In some embodiments, the thickness of the single-layer board (corresponding to the upper layer board 11 and the lower layer board 12) is 1.2 mm, and the material of the single-layer board is aluminum. The electrical connection member between battery cells can be called an aluminum bar in these embodiments. The axis of the battery cell observation hole 14 generally coincides with the center line of the battery cell pole. The battery cell pole welding area is generally the projection of a circular area with the center of the battery cell pole as the center and a radius of 15 mm on the lower layer board 12. The shape of the battery cell pole welding point is generally a circle with the center of the battery cell pole as the center and a radius of 5 mm.

[0027] In some embodiments, a U-shaped buffer groove 16 is stamped on the connector body 1 at a position corresponding to the gap between two adjacent single cells (here it is a double layer). The depth d of the buffer groove 16 satisfies: d ≤ h + t - s; where h represents the height of the cell terminal post, t represents the thickness of the lower layer plate 12 (corresponding to the thickness of the cell terminal post welding area), and s represents the safety gap, s = 0.5 mm. The buffer groove 16 can effectively buffer the pulling stress generated by the expansion of the cell on the connector body 1. The deeper the buffer groove 16 sinks downward, the more effective it is in relieving the expansion force. However, limited by the height of the cell terminal post and the cell terminal post welding area, the maximum value of the depth d of the buffer groove 16 is equal to h + t - s.

[0028] In some embodiments, the anti-expansion hole 15 is an arc-shaped hole that bends towards the cell terminal post welding area. The radial width range of the anti-expansion hole 15 is: 1.5 mm to 2.5 mm. The anti-expansion hole adopts an arc-shaped hole. This size design of the anti-expansion hole not only effectively prevents expansion and pulling, but also ensures the strength of the connector body, does not affect the structural strength of the connector body under static conditions, and does not affect current carrying. As an example, the radial width of the anti-expansion hole 15 is 2 mm.

[0029] In some embodiments, the radial distance between the inner edge of the anti-expansion hole 15 and the edge of the cell terminal post solder joint is greater than or equal to 11 mm. The opening position of the anti-expansion hole 15 can well avoid the welding of the cell terminal post and does not affect the welding quality of the cell terminal post.

[0030] In some embodiments, the arc-shaped contour of the arc-shaped avoidance notch 13 is conformable to a part of the contour of the cell terminal post solder joint, and the radial distance between the arc-shaped contour of the arc-shaped avoidance notch 13 and the edge of the cell terminal post solder joint is greater than or equal to 11 mm. The conformable design of the arc-shaped avoidance notch 13 with a part of the contour of the cell terminal post solder joint and an appropriate distance well avoids the welding of the cell terminal post and does not affect the welding quality of the cell terminal post.

[0031] An embodiment of the present invention also provides a battery module, which includes a plurality of single cells, and two adjacent single cells are connected by the aforementioned electrical connector between cells, that is, the two cell terminal post welding areas of the lower layer plate 12 are bonded and welded to the terminal posts of two adjacent single cells.

[0032] An embodiment of the present invention also provides a battery pack, which includes the aforementioned battery module.

[0033] An embodiment of the present invention also provides an electric vehicle, which includes the aforementioned battery pack.

[0034] The above are only specific embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model can easily conceive of changes or substitutions, which should all be covered within the protection scope of the present utility model.

Claims

1. An electrical connector between battery cells, comprising a connector body (1); characterized in that: The connector body (1) is a double-layer structure formed by folding and pasting an entire piece together, and comprises an upper plate (11) and a lower plate (12); the left and right parts of the lower plate (12) both have a cell pole welding area, and the left and right parts of the upper plate (11) both have an arc-shaped avoidance notch (13) for avoiding the cell pole welding area; the two cell pole welding areas of the lower plate (12) both have a cell observation hole (14), and two anti-expansion holes (15) are provided between the two cell pole welding areas of the lower plate (12), and the two anti-expansion holes (15) are respectively close to the two cell pole welding areas.

2. The electrical connector between cells according to claim 1, characterized in that: The anti-expansion hole (15) is an arc-shaped hole, which is bent towards the welding area of ​​the battery cell pole.

3. The inter-cell electrical connector according to claim 2, characterized in that: The radial width of the anti-expansion hole (15) ranges from 1.5 mm to 2.5 mm.

4. The inter-cell electrical connector according to claim 3, characterized in that: The radial distance between the inner edge of the anti-expansion hole (15) and the edge of the welding point of the battery cell pole is greater than or equal to 11 mm.

5. The inter-cell electrical connector according to claim 2, characterized in that: The arcuate contour of the arcuate avoidance notch (13) follows the contour of part of the battery cell pole welding point, and the radial distance between the arcuate contour of the arcuate avoidance notch (13) and the edge of the battery cell pole welding point is greater than or equal to 11 mm.

6. The electrical connector between battery cells according to any one of claims 1 to 5, characterized in that: A U-shaped buffer groove (16) is punched on the connector body (1) at a position corresponding to the gap between two adjacent single battery cells.

7. The inter-cell electrical connector according to claim 6, characterized in that: The depth d of the buffer groove (16) satisfies: d≤h+ts; wherein h represents the height of the battery cell pole, t represents the thickness of the lower plate (12), and s represents the safety gap, s=0.5 mm.

8. A battery module, comprising a plurality of single cells, characterized in that: Two adjacent single battery cells are connected by the inter-battery cell electrical connector as claimed in any one of claims 1 to 7.

9. A battery pack, characterized in that: Comprising the battery module as claimed in claim 8.

10. An electric vehicle, characterized in that: Comprising the battery pack as claimed in claim 9.

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