CN220774677U

CN220774677U - Connection structure, battery cell, single-layer planar battery module and multi-layer stacked battery module

Info

Publication number: CN220774677U
Application number: CN202223437431.3U
Authority: CN
Inventors: 汪子琪; 汪纯
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-11-14
Filing date: 2022-12-21
Publication date: 2024-04-12
Anticipated expiration: 2032-12-21

Abstract

The utility model discloses a connecting structure, a battery cell, a single-layer planar battery module and a multi-layer stacked battery module, wherein the connecting structure is used for keeping tight electrical connection and reliable connection between a battery pole and a bus bar, and is used for wrapping and tightly connecting the battery pole and the bus bar stably and firmly by wrapping and abutting at least the periphery of an overlapped part of a protruding part of a pole piece arranged on a battery top base and the bus bar and wrapping and abutting between the protruding part and the bus bar side edge through a loop.

Description

Connection structure, battery cell, single-layer planar battery module and multi-layer stacked battery module

Technical Field

The utility model belongs to the technical field of new energy, and particularly relates to a connecting structure, a battery cell, a single-layer planar battery module and a multi-layer stacked battery module.

Background

When the power cells are used in groups, reliable electrical connection of the poles to the busbar is a fundamental requirement. The battery pole and the bus bar are mostly hard sheet conductors, and in a vibration state, the bus bar and the pole may generate vibration in different directions and frequencies, and stress transmitted to the pole by the bus bar easily causes reliability problems such as looseness, bus bar tearing and the like of an electric connection point. As the cell capacity increases, the cross-sectional area (electric flux) requirements for the sheet conductors increase accordingly, the sheet conductors become stiffer and stiffer, the stress transfer tends to be stronger, and the reliability pressure of the electrical connection points tends to increase accordingly.

The prior art mainly adopts three technological modes of heat welding, press fit connection and adhesive connection. The thermal welding process adopts a metal welding process (spot welding and laser welding) with larger penetration and electric connection (ultrasonic welding) with shallower penetration/weaker connection strength, and is matched with a composite method of integrating external structures of integral glue injection among batteries. However, the greatest technical disadvantage of the thermal welding process is to have a thermal influence on the battery.

The press-fit connection process adopts metal press-fit lamination (cold connection), and the center of a bolt or a rivet penetrates through the periphery of a fastening busbar and the like to complete mechanical locking. The through points of the bolts and the rivets in the press fit connection process lead to loss of the electric communication area, and meanwhile, potential reliability hazards such as loosening of the bolts or the rivets, occurrence of metal fatigue and the like exist.

The adhesive connection process fills conductive adhesive between the bus bar and the pole, and combines the peripheral adhesive for fixation, and the longitudinal stripping force of the adhesive is difficult to be obviously improved along with the increase of the adhesive area, so that the stripping force between the bus bar and the pole is weaker than that of the two processes of hot welding and press fit connection. In addition, the adhesive filled between the bus bar and the top pole mainly provides longitudinal peeling force strength, and cannot provide enough peeling force in the transverse direction (the horizontal shearing direction of the adhesive), so that transverse loosening easily occurs between the bus bar and the pole in the strong shock or long-term use process.

Therefore, how to ensure that the longitudinal and transverse connection stability (further ensuring the stability of the electric flux) can be ensured under strong shock under the condition that the overcurrent capacity of the electric connection point is enough is always the direction of the industry.

Disclosure of Invention

Therefore, the utility model aims to overcome the defects in the prior art and provide a connecting structure, a battery cell, a single-layer planar battery module and a multi-layer stacked battery module, which can realize stable longitudinal and transverse connection between a busbar and a battery pole and ensure enough electric connection overcurrent capacity.

The utility model aims at being completed through the following technical scheme, a connecting structure is used for fastening connection between a battery pole and a busbar, and comprises the following components: the battery pole comprises a pole piece, wherein the pole piece extends to two sides along the horizontal direction to form an extension part, and the lower surface of the extension part is provided with a space; a busbar longitudinally stacked on the top of the battery post and longitudinally abutted against at least the protruding portion; and a collar at least partially surrounding the lateral peripheries of the extension part and the bus bar and respectively connected with the top part of the extension part and the bottom part of the bus bar so as to be suitable for fastening and connecting the battery pole with the bus bar at least along the longitudinal direction.

According to the utility model, the bus bar is longitudinally abutted against the protruding part of the pole piece, and the ring sleeve is wrapped on the protruding part and the periphery of the bus bar, especially at least wrapped on the lateral periphery of the protruding part and the bus bar and respectively connected with the top part of the protruding part and the bottom part of the bus bar, so that the longitudinal peeling strength can be provided, the connection stability of the bus bar and the battery pole is also improved in the transverse direction, the press-fit connection is not needed, and the electric area loss caused by the connection is avoided.

Further, according to the connecting structure of the utility model, the parts of the ring sleeve at the lateral periphery are connected and integrally formed at the bottoms of the protruding parts, so that a complete ring sleeve is formed.

Further, in the connecting structure of the utility model, conductive adhesive is arranged between the opposite surfaces of the battery pole and the busbar longitudinal stack.

Furthermore, in the connecting structure, the conductive adhesive is cold welding adhesive.

Further, in the connection structure of the present utility model, the protruding portion and the bus bar are formed to be equal in width in the loop wrapping area.

Further, in the connecting structure of the present utility model, an adhesive is provided between at least one of the collar and the bus bar longitudinal abutment surface, between the collar and the extension portion longitudinal abutment surface, between the collar and the bus bar side portion, and between the collar and the extension portion side portion.

Further, in the connecting structure of the present utility model, a concave-convex contact surface is formed between the collar and the bus bar longitudinal abutting surface and/or between the collar and the extension portion longitudinal abutting surface.

Furthermore, in the connecting structure, the loop is formed by overlapping two ends of the strip material to form a closed structure.

Further, in the connecting structure of the utility model, the loop is formed into an open structure by mutually spacing two ends of the strip.

Further, in the connection structure of the present utility model, the collar is made of a resin material.

Further, in the connecting structure of the utility model, the ring sleeve is made of a light-transmitting material.

Further, in the connecting structure of the utility model, the ring sleeve is made of metal material.

The utility model aims at being completed through the following technical scheme, and the connecting structure is used for fastening connection among buses of different sections and comprises the following steps: at least two different segments of buss bars, each of the buss bars comprising an extension, the extensions of the at least two buss bars being at least partially longitudinally stacked and abutted; and a collar at least partially surrounding the lateral periphery of the extension parts of the at least two buses and respectively connected with the top of the top bus and the bottom of the bottom bus so as to be suitable for fastening and connecting the two buses at least along the longitudinal direction.

Further, according to the connecting structure of the utility model, the part of the ring sleeve at the lateral periphery is connected with and integrally formed at the bottom of the bottom busbar, so that a complete ring sleeve is formed.

The utility model aims at completing a battery unit through the following technical scheme, the battery unit comprises a battery body and a battery pole column arranged at the top of the battery body, and is characterized in that the battery pole column comprises a base and pole column sheets arranged at the top of the base, the pole column sheets extend out of the base to two sides in the horizontal direction to form protruding parts, so that the bus bars are suitable for being longitudinally stacked at the top of the battery pole column and at least longitudinally abutted against the protruding parts, and are arranged on the protruding parts and the periphery of the bus bars in a wrapping mode through a loop in a wrapping mode, and are abutted against the protruding parts and the bus bars along the wrapping circumferential direction, and the battery pole column and the bus bars are fixedly connected, wherein the protruding parts at the wrapping position are the same in width.

The utility model aims at being completed through the following technical scheme that the single-layer planar battery module comprises a plurality of planar arranged battery monomers, wherein each battery monomer comprises a battery body and battery poles arranged at the top of the battery body, the tops of the battery poles are longitudinally stacked with bus bars, at least one battery pole comprises a base and pole pieces arranged at the tops of the base, and the pole pieces extend out of the base to two sides along the horizontal direction to form an extending part; the bus bar is longitudinally stacked on the top of the battery pole and is longitudinally abutted against at least the protruding part; the ring sleeve is arranged around the periphery of the extending part and the bus bar, and is abutted against the extending part and the bus bar along the circumferential direction of the wrapping so as to be suitable for fastening and connecting the battery pole with the bus bar.

The utility model aims at being completed through the following technical scheme that the multi-layer stacked battery module comprises at least two layers of planar battery modules, each layer of planar battery module comprises a plurality of planar arranged battery cells, each battery cell comprises a battery body and battery poles arranged at the top of the battery body, the tops of the battery poles are longitudinally stacked with bus bars, the battery cells of the at least two layers of planar battery modules are longitudinally opposite one to another, at least one battery pole comprises a base and pole pieces arranged at the top of the base, and the pole pieces extend out of the base to two sides along the horizontal direction to form an extension part; the bus bar is longitudinally stacked on the top of the battery pole and is longitudinally abutted against at least the protruding part; the ring sleeve is arranged around the periphery of the extending part and the bus bar, and is abutted against the extending part and the bus bar along the circumferential direction of the wrapping so as to be suitable for fastening and connecting the battery pole with the bus bar.

By the utility model, the following technical effects are realized:

and the sufficient longitudinal and transverse peeling strength can be provided simultaneously only through the annular sleeve, so that the electric area loss caused by the press-fit connection process is avoided, and the stable connection and stable electric flux between the busbar and the battery post are ensured.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present utility model, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a battery cell according to the present utility model;

FIG. 2 is a schematic diagram of a connection structure according to the present utility model;

FIG. 3 is a cross-sectional view of a first embodiment of the connection structure of the present utility model;

FIG. 4 is a cross-sectional view of a connection structure according to a second embodiment of the present utility model;

fig. 5 is a cross-sectional view of a third embodiment of the connection structure of the present utility model.

The reference numerals of the utility model are as follows:

1-battery pole, 11-pole piece, 111-extension, 12-base, 2-busbar, 3-loop, 4-conductive adhesive, 51-first adhesive, 52-second adhesive, 53-third adhesive.

Detailed Description

The following description of the embodiments of the present utility model will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the utility model are shown.

The components of the embodiments of the present utility model generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the utility model, as presented in the figures, is not intended to limit the scope of the utility model, as claimed, but is merely representative of selected embodiments of the utility model.

Definition of the definition

In the utility model, the battery cell can be a cylindrical battery cell, a square battery cell or other battery cells, and the utility model can be applied only if the battery cell has a battery pole and needs to be connected with a bus bar. In the present utility model, "longitudinal" refers to a direction extending along the height of the battery cell, and "transverse" refers to a direction extending perpendicular to the height of the battery cell. In the present utility model, "connected" encompasses not only physical connections but also electrical connections.

Battery cell

The battery unit of the utility model comprises a battery body and a battery pole 1 arranged at the top of the battery body, as shown in fig. 1, in order to adapt to the connecting structure of the utility model, the battery pole 1 comprises a base 12 and a pole piece 11 arranged at the top of the base 12, wherein the base 12 is preferably cylindrical and is prepared from a conductive material, the bottom of the base is fixedly connected with the battery body, and the electric connection is realized inside the battery body. The pole piece 11 is arranged at the top of the base 12 in a fixed connection mode, the pole piece 11 and the base 12 can be integrally formed, and the base 12 can provide a supporting function for the pole piece 11, and the pole piece 11 is electrically and conductively communicated with the inside of the battery body through the base 12.

The area of the pole piece 12 of the present utility model projected in the longitudinal direction should form an extended structure as compared to the base 12 for encircling the pole piece 12. According to one embodiment of the present utility model, as shown in fig. 2, the pole piece 11 is rectangular, the center of the rectangle coincides with the cylindrical center of the base 12, the long sides of the rectangle coincide with the length extending direction of the bus bar, and the long sides of the rectangle respectively extend from two sides of the base 12 to form a certain distance to form an extension part 111, so that the ring 3 is used for fastening the bus bar 2 and the battery pole 1 in the two extension part 111 areas at the same time, and the fastening balance and stability between the bus bar 2 and the battery pole 1 are ensured.

In another embodiment, the dimensions of the short sides of the rectangular shapes of the pole pieces 11 are equal to the widths of the bus bars 2, that is, the short sides of the rectangular shapes of the pole pieces 11 are overlapped with the corresponding sides of the bus bars 2 in the longitudinal projection, so that the lateral sides of the ring sleeve 3 are ensured to simultaneously abut against the short sides of the pole pieces 11 and the corresponding sides of the bus bars 2, and the transverse fastening force of the two is ensured. Those skilled in the art will appreciate that "equal width" herein is not an absolute equal width, as long as it is approximately equal.

In another embodiment (not shown in the drawings), the top of the battery body is not provided with a base, but is directly provided with a pole piece, the middle of the pole piece is concave, and two sides of the pole piece transversely extend to form a protruding part, and a space is reserved between the bottom of the protruding part and the top of the battery body, so that the bottom of the protruding part is conveniently wrapped with a ring sleeve.

Bus bar

The busbar 2 of the present utility model has a structure similar to that of the prior art, and is mainly used for realizing the electrical connection between the plurality of battery poles 1 in the battery module. The area of busbar 2 corresponding to battery post 1 is rectangular shape, extends along battery post long limit direction, and busbar 2 vertically piles up and sets up in post piece 11 top, and busbar 2 can be along the plane of transversely extending for realize full plane between busbar 2 bottom plane and the post piece 11 top plane and support tight contact. In another embodiment, the busbar 2 may also extend in a transverse direction not completely in a plane, for example, a bending structure is provided, but at least in a plane corresponding to the protruding portion 111 of the pole piece 11, so as to ensure that the bottom of the busbar 2 is in abutting contact with at least a partial plane of the top plane of the protruding portion 111 of the pole piece 11.

As described above, the side edges of the bus bar 2, particularly the side edges of the bus bar 2 corresponding to the protruding portions 111 of the pole pieces 11 are set to be the same width as the pole pieces 11, or at least the same width in the surrounding area of the ring, so that the side portions of the ring 3 are ensured to simultaneously abut against the short sides of the pole pieces 11 and the corresponding edges of the bus bar 2, and the transverse fastening force of the two is ensured.

Ring cover

The loop 3 of the present utility model is used for wrapping the outer circumferences of the extension portion 111 and the busbar 2, the loop 3 is formed by bending a strip material, and an open structure loop or a closed structure loop is formed in a state of wrapping the outer circumferences of the extension portion 111 and the busbar 2. For the closed structure, as shown in fig. 3, two ends of the strip of the ring sleeve 3 are mutually overlapped, and under the condition, a friction force in a compressed state exists between the overlapped parts, so that the ring sleeve 3 is further resisted to be loosened, and the fastening between the busbar 2 and the battery pole 1 is ensured. Under the condition that the two ends of the strip material of the ring sleeve 3 are mutually overlapped or the end parts are in butt joint fit, the two ends of the strip material are connected in a welding and bonding mode, and when the ring sleeve 3 is made of a material with stronger plastic, elastic rebound is not easy to occur during tightening, and any connecting mode can be omitted.

As shown in fig. 4, for the open structure form, the two ends of the strip of the ring 3 are spaced from each other, in this case, although no mutual tension force is generated between the two ends of the strip, a material with stronger plastic may be used, elastic rebound is not easy to occur during tightening, and the ring 3 can be ensured to stably wrap the busbar 2 and the battery post 1 for a long period of time without connecting the two ends of the strip.

As shown in fig. 5, the loop 3 may be of a split type, i.e., the loop 3 is wrapped around only the bus bar 2 and the outer circumference of the side portion of the extension 111, and the loop 3 is only partially connected at the top of the bus bar 2 and the bottom of the extension 111, thereby achieving the fastening of the bus bar 2 and the extension 111 in the longitudinal direction.

Connection structure

In the connection structure of the present utility model, as shown in fig. 3 and 4, the ring 3 is provided around the outer circumferences of the protruding portion 111 and the bus bar 2, and abuts against the protruding portion 111 and the bus bar 2 in the circumferential direction of the wrapping, thereby achieving simultaneous fastening in the longitudinal and transverse directions of the battery post 1 and the bus bar 2.

In one embodiment, the battery pole 1 is longitudinally stacked against the busbar 2, on the one hand, friction is generated between the abutting contact surfaces to provide lateral tightening force, and on the other hand, the abutting contact can ensure a current flow path. In another embodiment, the conductive adhesive 4 is disposed between the abutting contact surfaces of the battery post 1 and the busbar 2, which are longitudinally stacked, so as to further improve the longitudinal peel strength of the battery post 1 and the busbar, and the conductive adhesive 4 ensures a current flow path. In another embodiment, the conductive adhesive 4 may be disposed only between the battery post 1 and the busbar 2 in the area surrounded by the collar 3, may be disposed only in the area of the protruding portion 111, and may be disposed only in the area of the non-protruding portion 111.

In one embodiment, a first adhesive 51 is provided between the collar 3 and the longitudinal abutment surface of the busbar 2, and a second adhesive 52 is provided between the collar 3 and the longitudinal abutment surface of the extension 111, so as to avoid longitudinal loosening between the collar 3 and the busbar 2, the extension 111. In another embodiment, a third adhesive 53 is provided between the collar 3 and the side of the busbar 2 and between the collar 3 and the side of the extension 111, so as to avoid lateral loosening between the collar 3 and the busbar 2 and the extension 111.

In one embodiment, the collar 3 is made of a resin material so as to be firmly connected with the busbar 2, the protruding portion 111 by an adhesive. In another embodiment, the adhesive may be a structural adhesive or polyurea, and when the adhesive is a UV adhesive, the collar 3 is made of a light-transmitting resin material, and the UV adhesive may be directly irradiated and cured through the collar 3.

In one embodiment, the collar 3 is made of a metal material that has a greater resistance to rebound, ensuring that the collar 3 is securely wrapped around the bus bar 2 and the periphery of the extension 111 after a long period of use. In one embodiment, a concave-convex contact surface abutting matching structure can be adopted between the longitudinal abutting surfaces of the ring sleeve 3 and the bus bar 2 and between the longitudinal abutting surfaces of the ring sleeve 3 and the extending part 111, and the concave-convex structures are matched with each other in a microcosmic way, so that the transverse fastening force between the ring sleeve 3 and the bus bar 2 and between the ring sleeve 3 and the extending part 111 is further improved.

The connecting structure of the present utility model can also be applied to the interconnection between two different bus bars 2, each of which includes an extension portion, at least two extension portions are stacked longitudinally and abutted, and the two bus bars 2 are fastened and connected longitudinally and laterally at the same time by wrapping the outer circumference of the longitudinally stacked region of the extension portions of the two bus bars 2 with a loop 3.

Battery module

The single-layer planar battery module comprises a plurality of planar arranged battery cells, wherein each battery cell comprises a battery body and a battery pole 1 arranged at the top of the battery body, a bus bar is longitudinally stacked at the top of the battery pole 1, the battery pole 1 comprises a base 12 and pole pieces 11 arranged at the top of the base, and the pole pieces extend out of the base 12 to two sides along the horizontal direction to form an extension part 111; the bus bar 2 is longitudinally stacked on top of the battery pole 1 and is longitudinally abutted against at least the protruding portion 111; the ring 3 is provided around the outer periphery of the extension 111 and the bus bar 2, and abuts against the extension 111 and the bus bar 2 in the circumferential direction of the wrapping, so as to be suitable for fastening and connecting the battery post 1 and the bus bar 2.

The utility model relates to a multilayer stacked battery module, which comprises a multilayer planar battery module, wherein each layer of planar battery module comprises a plurality of planar arranged battery cells, each battery cell comprises a battery body and battery poles 1 arranged at the top of the battery body, the tops of the battery poles 1 are longitudinally stacked with bus bars 2, the battery cells of the multilayer planar battery module are longitudinally opposite one to another, each battery pole 1 comprises a base 12 and pole pieces 11 arranged at the top of the base, and each pole piece 11 extends out of the base 12 to two sides along the horizontal direction to form an extension part 111; the bus bar 2 is longitudinally stacked on top of the battery pole 1 and is longitudinally abutted against at least the protruding portion 111; the ring 3 is provided around the outer periphery of the extension 111 and the bus bar 2, and abuts against the extension 111 and the bus bar 2 in the circumferential direction of the wrapping, so as to be suitable for fastening and connecting the battery post 1 and the bus bar 2.

All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present utility model, and not for limiting the same; although the utility model has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the utility model.

Claims

1. A connection structure for fastening connection between a battery post and a bus bar, comprising:

the battery pole comprises a pole piece, wherein the pole piece extends to two sides along the horizontal direction to form an extension part, and the lower surface of the extension part is provided with a space;

a busbar longitudinally stacked on the top of the battery post and longitudinally abutted against at least the protruding portion;

and a collar at least partially surrounding the lateral peripheries of the extension part and the bus bar and respectively connected with the top part of the extension part and the bottom part of the bus bar so as to be suitable for fastening and connecting the battery pole with the bus bar at least along the longitudinal direction.

2. The connection structure according to claim 1, wherein the portion of the collar at the lateral periphery is connected and integrally formed at the bottom of the protruding portion, thereby forming a complete collar.

3. The connection structure according to claim 1, wherein a conductive paste is provided between the battery post and the opposite surface of the busbar longitudinal stack.

4. A connection according to claim 3, wherein the conductive glue is cold-welded glue.

5. The connection structure according to claim 1, wherein the protruding portion and the bus bar are formed to be equal in width at the loop wrapping area.

6. The connection structure according to claim 1, wherein at least one of between the collar and the bus bar longitudinal abutment surface, between the collar and the projection longitudinal abutment surface, between the collar and the bus bar side, and between the collar and the projection side is provided with an adhesive.

7. The connection structure according to claim 1, wherein a concave-convex contact surface is formed between the collar and the bus bar longitudinal abutment surface and/or between the collar and the projection longitudinal abutment surface.

8. The connecting structure as set forth in claim 1, wherein said loop is formed by overlapping two ends of said strip material to form a closed structure.

9. The connecting structure of claim 1, wherein said loops are formed in an open configuration by spaced apart ends of the strip.

10. The connection structure according to claim 1, wherein the collar is made of a resin material.

11. The connection according to claim 10, wherein the collar is made of a light-transmitting material.

12. The connection according to claim 1, wherein the collar is made of a metallic material.

13. A connection structure for connection between bus bars of different sections, comprising:

at least two different segments of buss bars, each of the buss bars comprising an extension, the extensions of the at least two buss bars being at least partially longitudinally stacked and abutted;

and a collar at least partially surrounding the lateral periphery of the extension parts of the at least two buses and respectively connected with the top of the top bus and the bottom of the bottom bus so as to be suitable for fastening and connecting the two buses at least along the longitudinal direction.

14. The connection structure according to claim 13, wherein the portion of the collar at the lateral periphery is connected and integrally formed at the bottom of the busbar, thereby forming a complete collar.

15. The utility model provides a battery monomer, includes the battery body and sets up at the battery post at battery body top, its characterized in that, the battery post include the base with set up in the post piece at base top, the post piece stretches out to both sides along the horizontal direction the base forms the extension, in order to be suitable for the busbar vertically pile up in battery post top and at least with the extension vertically support tightly, thereby through the ring cover wrap up set up in extension with the periphery of busbar, and with extension with the busbar is followed the circumference of wrapping supports tightly, will the battery post with busbar fastening connection, wherein, the extension of wrapping up setting department is with the busbar is the same width.

16. The single-layer planar battery module comprises a plurality of planar arranged battery cells, wherein each battery cell comprises a battery body and battery poles arranged at the top of the battery body, and bus bars are longitudinally stacked at the top of the battery poles; the bus bar is longitudinally stacked on the top of the battery pole and is longitudinally abutted against at least the protruding part; the ring sleeve is arranged around the periphery of the extending part and the bus bar, and is abutted against the extending part and the bus bar along the circumferential direction of the wrapping so as to be suitable for fastening and connecting the battery pole with the bus bar.

17. The multi-layer stacked battery module comprises at least two layers of planar battery modules, each layer of planar battery module comprises a plurality of planar arranged battery cells, each battery cell comprises a battery body and battery pole pieces arranged at the top of the battery body, the tops of the battery pole pieces are longitudinally stacked with bus bars, and the battery cells of the at least two layers of planar battery modules are longitudinally opposite one to another, and the multi-layer stacked battery module is characterized in that at least one battery pole piece comprises a base and pole piece arranged at the top of the base, and the pole piece extends out of the base from two sides in the horizontal direction to form an extending part; the bus bar is longitudinally stacked on the top of the battery pole and is longitudinally abutted against at least the protruding part; the ring sleeve is arranged around the periphery of the extending part and the bus bar, and is abutted against the extending part and the bus bar along the circumferential direction of the wrapping so as to be suitable for fastening and connecting the battery pole with the bus bar.