A multi-core package connection structure, square shell battery cell and battery module

Abstract

The utility model relates to the technical field of power batteries, and proposes a multi-core package connection structure, a square shell battery cell and a battery module, comprising a core package body, a positive pole tab and a negative pole tab, wherein the number of the core package bodies is multiple and arranged in sequence along the thickness direction, and the same side of the multiple core package bodies is provided with a tab connection surface, wherein the tab connection surface comprises an arc-shaped wrapping area and a square connection area, wherein the number of the arc-shaped wrapping areas is two and respectively located at the two ends of the tab connection surface. The multi-core package connection structure, square shell battery cell and battery module divide the area on the end surface of the core package, and arrange the positive pole tab and the negative pole tab in the two square connection areas with the largest area, so as to increase the designable area of ​​the positive pole tab and the negative pole tab, so that the current flow area of ​​the tabs connected in series with the core packages is no longer limited to a smaller size, thereby reducing the internal resistance after the core packages are connected, and improving the performance of the battery cell.

Description

Technical Field

[0001] The utility model relates to the technical field of power batteries, and in particular to a multi-core package connection structure, a square shell battery cell and a battery module. Background Art

[0002] Electric vehicles have been recognized by society for their energy-saving and environmentally friendly features. As the energy source of electric vehicles, power batteries directly affect the vehicle's power, reliability, safety and economy. Aluminum-shell square lithium battery packaging has high reliability, high system energy efficiency, relatively light weight, high energy density, relatively simple structure, and relatively convenient capacity expansion. It is an important option for increasing energy density by increasing single cell capacity. Battery modules are composed of battery cells, and battery modules are composed of battery packs to power the vehicle.

[0003] In the prior art, the positive electrode tabs and the negative electrode tabs are usually arranged near the two ends of the core package end surface. For example, the square aluminum shell battery cell structure with side-outlet tabs with publication number CN217641694U arranges the bus based on the tabs being arranged at both ends of the core package end surface to achieve side-outlet connection of the bus.

[0004] However, the method of arranging the positive electrode tab and the negative electrode tab near the two ends of the core package end face respectively will lead to a significant limitation on the tab arrangement area. When multiple core packages are connected in series inside a single battery cell, due to the small arrangement of the tabs, the flow area after connection is extremely limited, which will lead to an increase in the internal resistance of the battery cell. The increase in the internal resistance of the battery cell will make the heat generated by the battery cell during operation higher, which is not conducive to the thermal management of the battery cell and will reduce the power supply performance of the battery cell. Utility Model Content

[0005] In view of this, the utility model proposes a multi-core package connection structure, a square shell battery cell and a battery module, by dividing the area on the end surface of the core package, arranging the positive pole ear and the negative pole ear in the two square connection areas with the largest area, so as to increase the designable area of ​​the positive pole ear and the negative pole ear, so that the current flow area of ​​the ears connected in series with the core packages is no longer limited to a smaller size, thereby reducing the internal resistance after the connection between the core packages and improving the performance of the battery cell.

[0006] The technical solution of the utility model is achieved in this way:

[0007] On the one hand, the utility model provides a multi-core package connection structure, including a core package body, a positive electrode tab and a negative electrode tab, wherein:

[0008] The number of the core package bodies is multiple and they are arranged in sequence along the thickness direction. The same side of the multiple core package bodies is provided with a tab connection surface, and the tab connection surface includes an arc-shaped wrapping area and a square connection area. The number of the arc-shaped wrapping areas is two and they are respectively located at both ends of the tab connection surface. The number of the square connection areas is two and they are both arranged between the two arc-shaped wrapping areas.

[0009] The positive electrode tab and the negative electrode tab are respectively arranged on the two square connection areas of the core package body, and the two adjacent tabs on two adjacent core package bodies have opposite polarities and are electrically connected.

[0010] On the basis of the above technical solution, preferably, on all the core package bodies, the two pole tabs that are farthest apart are the positive pole tab and the negative pole tab.

[0011] On the basis of the above technical solution, preferably, both ends of the positive electrode tab and the negative electrode tab extend to the connection between the arc-shaped wrapping area and the square connecting area.

[0012] On the basis of the above technical solution, preferably, two adjacent pole ears on two adjacent core package bodies are bent toward opposite sides to fit together and are fixed by welding.

[0013] On the other hand, the utility model provides a square shell battery cell, comprising a shell, a pole and the above-mentioned multi-core package connection structure, wherein:

[0014] The core package bodies are all arranged in the shell;

[0015] There are two poles, both of which are arranged outside the shell, and the two poles are electrically connected to the two pole tabs that are farthest apart from each other.

[0016] On the basis of the above technical solution, preferably, it further includes two connecting plates, which are respectively fixed to the two pole ears that are farthest apart, and the two connecting plates are respectively fixed to the two poles, and the connecting plates are used to electrically connect the poles and the pole ears.

[0017] On the basis of the above technical solution, preferably, it further comprises an insulating tape, wherein the insulating tape is pasted on the tabs connecting two adjacent core package bodies, and the insulating tape is used to isolate the positive electrode tab from the negative electrode tab.

[0018] Further preferably, the connecting piece includes a first connecting section and a second connecting section, wherein:

[0019] The first connecting section is fitted and fixed to the tab;

[0020] The second connecting section is integrally formed with the first connecting section, and the second connecting section is bent toward the pole and welded to the pole.

[0021] On the basis of the above technical solution, preferably, the housing includes a shell and a top cover, wherein:

[0022] The shell is a hollow square shell with one side open, and the core package body is arranged in the shell;

[0023] The top cover is fixed to the opening side of the shell to seal the interior of the shell, and the two poles are both arranged on the top cover.

[0024] On the other hand, the utility model provides a battery module, including the above-mentioned square shell battery cell.

[0025] The multi-core package connection structure, square shell battery cell and battery module of the utility model have the following beneficial effects compared with the prior art:

[0026] (1) By dividing the area on the end surface of the core package, the positive electrode tab and the negative electrode tab are arranged in the two largest square connection areas to increase the designable area of ​​the positive electrode tab and the negative electrode tab, so that the current flow area of ​​the tabs connected in series with the core packages is no longer limited to a small size, thereby reducing the internal resistance after the core packages are connected, and improving the performance of the battery cell;

[0027] (2) Extending both ends of the positive electrode tab and the negative electrode tab to the connection between the arc-shaped wrapping area and the square connection area can maximize the length of the positive electrode tab and the negative electrode tab. In the actual core package arrangement process, due to the limited internal space of the battery cell, the width of the tab will be directly affected by the distance between the core package and the top cover. By maximizing the length of the tab, the connection area of ​​the tab can be maximized, thereby further improving its current capacity after connection and reducing the internal resistance of the battery cell after the core package is connected. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a schematic diagram of the multi-core package connection structure of the utility model;

[0030] Figure 2 It is a side view of the multi-core package connection structure of the utility model;

[0031] Figure 3This is a schematic diagram of the internal structure of the square shell battery cell of the utility model;

[0032] Figure 4 It is a side view of the square shell battery core connecting piece of the utility model. DETAILED DESCRIPTION

[0033] The following will be combined with the implementation of the utility model to clearly and completely describe the technical solutions in the implementation of the utility model. Obviously, the described implementation is only a part of the implementation of the utility model, not all of the implementations. Based on the implementation of the utility model, all other implementations obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0034] like Figure 1-2 As shown, the multi-core package connection structure of the present invention includes a core package body 1, a positive electrode tab 2 and a negative electrode tab 3.

[0035] There are multiple core package bodies 1, which are arranged in sequence along the thickness direction. A pole lug connection surface 11 is provided on the same side of the multiple core package bodies 1. The pole lug connection surface 11 includes an arc-shaped wrapping area 101 and a square connection area 102. There are two arc-shaped wrapping areas 101, which are respectively located at both ends of the pole lug connection surface 11. There are two square connection areas 102, which are both arranged between the two arc-shaped wrapping areas 101.

[0036] The core package body 1 is formed by stacking the positive electrode sheet, the negative electrode sheet and the separator, and during the winding process, the curved parts are gradually stacked to form the curved part of the core package body 1, and the straight parts are gradually stacked to form the stacked part of the core package body 1. The curved part corresponds to the pole ear connection surface 11 of the core package body 1, that is, forming an arc-shaped winding area 101, and the stacked part corresponds to the pole ear connection surface 11 of the core package body 1, that is, forming a square connection area 102.

[0037] The positive electrode tab 2 and the negative electrode tab 3 are respectively arranged on the two square connection areas 102 of the core package body 1 , and the two adjacent tabs on two adjacent core package bodies 1 have opposite polarities and are electrically connected.

[0038] The square connection area 102 is the longest part on the end surface of the core package body 1. The positive electrode tab 2 and the negative electrode tab 3 are arranged on the square connection area 102 to have the maximum length, so that the area of ​​the positive electrode tab 2 and the negative electrode tab 3 can be maximized under a limited width. Accordingly, after the positive electrode tab 2 and the negative electrode tab 3 are arranged in two square connection areas 102, the positive electrode tab 2 and the negative electrode tab 3 are mirror images of each other with the dividing line between the two square connection areas 102 as the symmetry line, and the multiple core package bodies 1 are facing Arranged in the thickness direction, in order to connect the pole ears of each core package body 1, the two adjacent pole ears on the two adjacent core package bodies 1 are of opposite polarity. Taking three core packages as an example, the three core packages are arranged from left to right, and the pole ears on the first core package are the positive pole ear 2 and the negative pole ear 3 respectively. The pole ears on the second core package and the third core package are also the positive pole ear 2 and the negative pole ear 3 respectively. The arrangement is reciprocating in this way, so that the two adjacent core packages are connected through the pole ears of different polarities to realize the series connection of multiple core packages.

[0039] Taking into account that after multiple core packages are connected, the two unconnected pole ears that are finally left are preferably of different polarities. Therefore, in this embodiment, on all the core package bodies 1, the two pole ears that are farthest apart are the positive pole ear 2 and the negative pole ear 3. This arrangement can make the two pole ears on the two core package bodies 1 at both ends that are not connected to other pole ears have different polarities, thereby making it easier to set up components to connect the pole ears at both ends to the electrodes.

[0040] As a preferred embodiment, both ends of the positive electrode tab 2 and the negative electrode tab 3 extend to the connection between the arc-shaped winding area 101 and the square connection area 102. This arrangement can maximize the length of the positive electrode tab 2 and the negative electrode tab 3. In the actual core package arrangement process, due to the limited internal space of the battery cell, the width of the tab will be directly affected by the distance between the core package and the top cover. By maximizing the length of the tab, the connection area of ​​the tab can be maximized, thereby improving its current capacity after connection and reducing the internal resistance of the battery cell after the core package is connected.

[0041] In this embodiment, two adjacent pole ears on two adjacent core package bodies 1 are bent toward opposite sides and fit together, and then welded and fixed. Since the positive electrode sheet and the negative electrode sheet are stacked and wound, and the pole ears are layered, there is a gap between the stacked sheets of the pole ears that is consistent with the thickness of the diaphragm. During the connection process, the two pole ears of different polarities need to be bent slightly toward opposite sides and fit together completely, and then fixed by ultrasonic welding. In addition, during ultrasonic welding, the more welding points there are, the better the current carrying capacity after connection.

[0042] like Figure 3-4 As shown, the square shell battery cell of the present invention comprises a shell 10, a pole 20 and the above-mentioned multi-core package connection structure.

[0043] The core package body 1 is arranged in the shell 10. The shell 10 is an aluminum shell. The shell 10 is the outer protective shell of the square shell battery cell and is used to load electrolyte and multiple core packages to form a minimum power supply unit.

[0044] There are two poles 20, and both are arranged on the outside of the shell 10. The two poles 20 are electrically connected to the two pole ears that are farthest apart. The setting position of the pole 20 is the same as that in the prior art. It is located on the end face of the shell 10 and arranged along the length direction of the end face. In the prior art, the position of the pole ear directly corresponds to the pole 20, while in this embodiment, in order to increase the flow area between the pole ears, the position of the pole ears is changed.

[0045] Specifically, after the position of the pole lug is changed, the required transition structure is also changed accordingly. In the present embodiment, two connecting pieces 30 are provided as transition components between the pole lug and the pole 20. The two connecting pieces 30 are respectively fixed to the two pole lugs that are farthest apart, and the two connecting pieces 30 are respectively fixed to the two poles 20. The connecting pieces 30 are used to electrically connect the pole 20 with the pole lug.

[0046] The two pole ears with different polarities at both ends are switched by two connecting pieces 30 , so as to be connected to the two poles 20 respectively.

[0047] In addition, for the connection of the pole ears of different polarities on the opposite sides, an insulating tape 40 is required. The insulating tape 40 is pasted on the pole ears connecting two adjacent core package bodies 1. The insulating tape 40 is used to isolate the positive pole ear 2 from the negative pole ear 3. The insulating tape 40 is provided to protect the pole ears of different polarities arranged in pairs, avoid the contact between the pole ears and the connecting sheet 30 to cause an internal short circuit of the battery cell, and improve the stability of the battery cell.

[0048] In this embodiment, the connecting piece 30 includes a first connecting section 301 and a second connecting section 302, the first connecting section 301 is fitted and fixed to the pole ear, the second connecting section 302 is integrally formed with the first connecting section 301, the second connecting section 302 is bent toward the pole 20 and welded to the pole 20, wherein the length of the first connecting section 301 is consistent with the length of the pole ear, and is fixed to the pole ears on both sides by ultrasonic welding. Since the pole ear is not parallel to the end face of the core package during the production process, the second connecting section 302 needs to be bent when connecting to the pole 20 so that one side is located at the bottom of the pole 20, and then connected to the bottom of the pole 20 by ultrasonic welding. It should be noted that after bending, the second connecting section 302 needs to completely cover the side of the pole 20 located in the shell 10 to avoid increased internal resistance due to cold welding.

[0049] In this embodiment, the shell 10 includes a shell 50 and a top cover 60. The shell 50 is a hollow square shell with an opening on one side. The core package body 1 is arranged in the shell 50. The top cover 60 is fixed to the open side of the shell 50 to seal the interior of the shell 50. The two poles 20 are both arranged on the top cover 60.

[0050] Since the top cover 60 and the shell 50 are both made of aluminum, in order to avoid direct contact between the pole 20 and the top cover 60 , an insulating ring needs to be provided outside the pole 20 to ensure that the two poles 20 will not cause a short circuit through the top cover 60 .

[0051] The battery module of the utility model comprises the square shell battery core mentioned above. A plurality of square shell battery cores are arranged and tied and fixed by a cable tie to form a battery module.

[0052] In addition, a plurality of battery modules can be assembled into a box to form a battery pack.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-core package connection structure, characterized in that: It comprises a core package body (1), a positive electrode tab (2) and a negative electrode tab (3), wherein: The core package bodies (1) are multiple in number and arranged in sequence along the thickness direction; a tab connection surface (11) is provided on the same side of the multiple core package bodies (1); the tab connection surface (11) comprises an arc-shaped wrapping area (101) and a square connection area (102); the arc-shaped wrapping areas (101) are two in number and are respectively located at two ends of the tab connection surface (11); the square connection areas (102) are two in number and are both provided between the two arc-shaped wrapping areas (101); The positive electrode tab (2) and the negative electrode tab (3) are respectively arranged on the two square connection areas (102) of the core package body (1), and the two adjacent tabs on two adjacent core package bodies (1) have opposite polarities and are electrically connected.

2. The multi-core package connection structure according to claim 1, characterized in that: On all the core package bodies (1), the two pole tabs that are farthest apart are the positive pole tab (2) and the negative pole tab (3).

3. The multi-core package connection structure according to claim 1, characterized in that: Both ends of the positive electrode tab (2) and the negative electrode tab (3) extend to the connection between the arc-shaped wrapping area (101) and the square connection area (102).

4. The multi-core package connection structure according to claim 1, characterized in that: Two adjacent pole ears on two adjacent core package bodies (1) are bent toward opposite sides to fit together and are fixed by welding.

5. A square shell battery cell, characterized in that: It comprises a housing (10), a pole (20) and the multi-core package connection structure as claimed in claim 2, wherein: The core package body (1) is arranged inside the shell (10); There are two poles (20), both of which are arranged outside the housing (10), and the two poles (20) are respectively electrically connected to two pole tabs that are farthest apart.

6. The square shell battery cell according to claim 5, characterized in that: It also comprises two connecting sheets (30), wherein the two connecting sheets (30) are respectively fixed to two pole tabs which are farthest apart, and the two connecting sheets (30) are respectively fixed to two pole posts (20), and the connecting sheets (30) are used to electrically connect the pole posts (20) and the pole tabs.

7. The square shell battery cell according to claim 5, characterized in that: It also includes an insulating tape (40), which is pasted on the pole tabs connecting two adjacent core package bodies (1), and the insulating tape (40) is used to isolate the positive pole tab (2) from the negative pole tab (3).

8. The square shell battery cell according to claim 6, characterized in that: The connecting piece (30) comprises a first connecting section (301) and a second connecting section (302), wherein: The first connecting section (301) is fitted and fixed to the tab; The second connecting section (302) and the first connecting section (301) are integrally formed, and the second connecting section (302) is bent toward the pole (20) and welded to the pole (20).

9. The square shell battery cell according to claim 5, characterized in that: The housing (10) comprises a shell (50) and a top cover (60), wherein: The shell (50) is a hollow square shell with one side open, and the core package body (1) is arranged in the shell (50); The top cover (60) is fixed to the open side of the housing (50) to seal the interior of the housing (50), and the two poles (20) are both arranged on the top cover (60).

10. A battery module, characterized in that: A square shell battery cell comprising any one of claims 5-9.

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