Battery module and battery pack
Patent Information
- Application Number
- PCT/CN2024/108689
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-03-05
- Filing Date
- 2024-07-31
- Publication Date
- 2025-10-02
AI Technical Summary
During the charge and discharge process, the volume of soft-pack lithium-ion single cells changes due to the "deep breathing" effect, causing the single cells to slip, resulting in misalignment between the PCB board and the tab, which may lead to breakage and reduce the reliability and safety of the battery pack.
Flexible first and second connectors are used to replace the integral PCB board. The cooperation of the first and second connectors absorbs the expansion of the single battery, avoids the tearing of the tabs, maintains the stability of the battery module connection, and reduces slippage through flexible connectors and supports, thereby improving the reliability and safety of the battery module.
It effectively absorbs the expansion of single cells, avoids the tearing of tabs, maintains stable connection of battery modules, reduces deformation, improves the reliability and safety of battery modules, and achieves lightweight design.
Smart Images
Figure CN2024108689_02102025_PF_FP_ABST
Abstract
Description
Battery modules and battery packs
[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on March 5, 2024, with application number 202420422777.6. The entire contents of the above application are incorporated by reference into this application.
[0002] Technical Field
[0003] The present application relates to the technical field of lithium batteries, for example, to a battery module and a battery pack.
[0004] Background Art
[0005] Soft-pack lithium-ion single cells have a "deep breathing" effect in the free state during the charge and discharge process, which is specifically manifested as a significant volume change of the single cell. Compared with the uncharged state, the lithium metal battery will expand in the fully charged state. In other words, the "deep breathing" effect of the single cell will cause the single cell to expand, resulting in uneven thickness and slippage between the single cells, causing the lithium metal battery to deform, which is not conducive to the charge and discharge cycle. Therefore, a restraining force needs to be applied in the thickness direction of the single cell to ensure the cycle.
[0006] Technical issues
[0007] To increase the battery's energy density, a battery pack contains multiple cells, connected in series and parallel via a printed circuit board (PCB). To prevent the PCB from breaking apart from the tabs, restraints are typically added to the four sides of the cell. However, the slippage of the cell due to the "deep breathing" effect can cause misalignment between the cell and the PCB. In severe cases, this can lead to the PCB breaking or the tabs being torn off, causing the entire battery pack to fail, resulting in low reliability and poor safety.
[0008] Technical Solutions
[0009] The present application provides a battery module, comprising: a plurality of single cells, a plurality of first connectors, and a plurality of second connectors;
[0010] The single cell has an end face, and the end face is provided with a tab;
[0011] The first connecting member and the second connecting member are both flexible members, the first connecting member has a first connecting portion, a second connecting portion and a bent portion, the first connecting portion and the second connecting portion are both sheet-shaped, and both ends of the bent portion are connected to the first connecting portion and the second connecting portion respectively;
[0012] Multiple single cells are stacked together, the first connecting portion connects the tabs of two adjacent single cells, the second connecting member is sheet-shaped, and the second connecting member connects the second connecting portions of two adjacent first connecting members, and the second connecting member, the first connecting portion and the second connecting portion are stacked on the end face of the single cell.
[0013] The present application provides a battery pack, comprising a box and a battery module. The battery module is disposed in the box, and the side surfaces of the battery module are in contact with the inner wall of the box.
[0014] Beneficial effects
[0015] The beneficial effects of the present application are as follows: by setting up multiple first connectors and second connectors, the single cells are connected separately through the first connector, and the cooperation of the first connector and the second connector replaces the original integral PCB board. When the single cell expands, the first connector and the second connector can more easily absorb the expansion of the single cell by deforming, thereby avoiding the tearing of the pole ear and the separation of the first connector and the second connector from the pole ear of the single cell, ensuring the stability of the connection between the single cells and avoiding short circuit in the battery module; by setting the second connector, the first connecting part and the second connecting part to overlap on the end face of the single cell, the overall shape of the battery module can be made close to a rectangular parallelepiped, and the first connector and the second connector are both flexible, so that the external restraining structure can provide compression and restraint to the six sides of the battery module, reduce the slippage phenomenon during the expansion of the single cell, reduce the deformation of the battery module, and improve the reliability and safety of the battery module.
[0016] BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG1 is a first schematic diagram of the connection between a single cell and a first connector provided by some implementations of the present application.
[0018] FIG2 is a second schematic diagram of the connection between a single cell and a first connector provided by some implementations of the present application.
[0019] FIG3 is a third schematic diagram of the connection between a single cell and a first connector provided by some implementations of the present application.
[0020] FIG4 is a first schematic diagram showing the connection between a single cell, a first connector, and a second connector provided in some implementations of the present application.
[0021] FIG5 is a second schematic diagram of the connection between a single cell, a first connector, and a second connector provided in some implementations of the present application.
[0022] FIG6 is a schematic diagram of a battery module provided by some implementations of the present application.
[0023] FIG7 is a first schematic diagram of the connection between a single cell and a first connector provided in other implementations of the present application.
[0024] FIG8 is a second schematic diagram of the connection between a single cell and a first connector provided in other implementations of the present application.
[0025] FIG9 is a third schematic diagram of the connection between a single cell and a first connector provided in other implementations of the present application.
[0026] FIG10 is a schematic diagram of the connection between a single battery, a first connector, and a second connector provided in other implementations of the present application.
[0027] FIG11 is a schematic diagram of a battery module provided by other implementations of the present application.
[0028] FIG12 is a schematic cross-sectional view of a battery pack provided in some implementations of the present application.
[0029] FIG13 is a schematic diagram of a battery pack decomposition provided by some implementations of the present application.
[0030] FIG14 is a schematic diagram of a battery pack provided by some implementations of the present application (one of the splicing plates is not shown).
[0031] FIG15 is a schematic diagram of a second buffer provided in some implementations of the present application.
[0032] FIG16 is a schematic diagram of a box and partitions provided by some implementations of the present application (one of the splicing plates is not shown).
[0033] FIG17 is a structural diagram of a tab in some implementations of the present application.
[0034] In the picture:
[0035] 1. Box body; 11. Splicing plate; 12. Spacer; 13. Current output socket;
[0036] 2. Second buffer; 21. Wire duct; 210. Wire; 22. Weight reduction hole;
[0037] 3. Battery module; 31. Power transmission side; 32. Single cell; 321. Edge sealing portion; 322. Tab; 3221. Third connecting portion; 3222. Fourth connecting portion; 323. Cell portion; 33. First connecting member; 331. First connecting member; 332. Second connecting member; 333. Bend portion; 34. Second connecting member; 35. Support member; 36. First buffer member.
[0038] Modes for Carrying Out the Invention
[0039] In the description of this application, unless otherwise specified or limited, the terms "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and can refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.
[0040] As shown in Figures 6 and 11 (part of the reference numerals refer to Figures 1 to 5, and Figures 7 to 10), a battery module 3 provided in the present application includes a plurality of single cells 32, a plurality of first connectors 33, and a plurality of second connectors 34. The single cells 32 have end faces, and the end faces are provided with tabs 322. The first connector 33 and the second connector 34 are both flexible members, that is, the first connector 33 and the second connector 34 are both flexible, and the first connector 33 and the second connector 34 can be deformed when under pressure. The first connector 33 has a first connecting portion 331, a second connecting portion 332, and a second connecting portion 333. The first connecting part 331 and the second connecting part 332 are both in the form of a sheet. Both ends of the bent part 333 are connected to the first connecting part 331 and the second connecting part 332 respectively. The multiple single batteries 32 are stacked together. The first connecting part 331 connects the tabs 322 of two adjacent single batteries 32. The second connecting part 34 is in the form of a sheet. The second connecting part 34 connects the second connecting parts 332 of two adjacent first connecting parts 33. The second connecting part 34, the first connecting part 331 and the second connecting part 332 are stacked on the end face of the single battery 32.
[0041] By providing a plurality of first connectors 33 and second connectors 34 , the single cells 32 are individually connected to each other through the first connectors 331 , and then connected to the second connectors 332 of the first connectors 33 through the second connectors 34 , thereby replacing the integrated PCB. In this embodiment, when the single cell 32 expands, the first connector 33 and the second connector 34 can more easily absorb the expansion of the single cell 32 by deforming, thereby preventing the tab 322 from being torn and the first connector 33 and the second connector 34 from being separated from the tab 322 of the single cell 32, thereby ensuring the stability of the connection between the single cells 32 and avoiding a short circuit in the battery module 3; by arranging the second connector 34, the first connecting portion 331 and the second connecting portion 332 to overlap on the end face of the single cell 32, the overall shape of the battery module 3 can be made close to a rectangular parallelepiped, and the first connector 33 and the second connector 34 are both flexible, then the external restraining structure can provide compression and restraint to the six sides of the battery module 3, reducing the slippage phenomenon during the expansion of the single cell 32, reducing the deformation of the battery module 3, and improving the reliability and safety of the battery module 3.
[0042] In this embodiment, the first connecting member 33 and the second connecting member 34 are both nickel sheets. The first connecting member 33 is bent to form a first connecting portion 331 , a bent portion 333 , and a second connecting portion 332 .
[0043] This embodiment uses the first connector 33 and the second connector 34 made of nickel sheets, which can reduce the weight of the battery module 3 and achieve a lightweight design.
[0044] 6 and 11 , the battery module 3 includes a support member 35 , and the single battery 32 has a core portion 323 and an edge sealing portion 321 . The thickness of the core portion 323 is greater than the thickness of the edge sealing portion 321 . A support member 35 is provided between the edge sealing portions 321 of two adjacent single batteries 32 . The support member 35 abuts against the side surfaces of the edge sealing portions 321 , and the side surfaces of some support members 35 are in contact with the first connector 33 and the second connector 34 , while the side surfaces of another part of the support member 35 are in contact with the second connector 34 alone. The single cell 32 in this embodiment is a soft-pack battery, and the edge sealing portion 321 is an aluminum-plastic film edge sealing portion, which is an inherent structure of the soft-pack battery. A support member 35 is provided. The support member 35 can fill the gap between the edge sealing portions 321 of two adjacent single cells 32 to reduce the deformation of the edge sealing portions 321. The support member 35 can also provide support for the first connecting member 33 and the second connecting member 34, reduce the degree of bending of the first connecting member 331, the second connecting member 332 and the second connecting member 34, and improve the reliability of the battery module 3.
[0045] In this embodiment, the support member 35 is a flexible support block. It is understood that the individual cells 32 will expand during the charge and discharge process, causing the volume of the individual cells 32 to change. By configuring the support member 35 as a flexible support block, the flexibility of the support member 35 can, to a certain extent, absorb the deformation of the individual cells 32, reducing deformation of the battery module 3 and improving the reliability and safety of the battery module 3. For example, the support member 35 can be ethylene-vinyl acetate copolymer (EVA Copolymer) foam.
[0046] 6 and 11 , the hardness of the support members 35 on both sides of the battery module 3 may be greater than the hardness of the support member 35 located in the center of the battery module 3 . The support members 35 on both sides of the battery module 3 are in direct contact with the external restraining structure, thereby providing a position limit for the single battery 32 .
[0047] A first sheet-shaped buffer 36 is provided between adjacent battery cells 32. This buffer 36 absorbs deformation of the battery cells 32, reducing deformation of the battery module 3 and improving the reliability and safety of the battery module 3. The first buffer 36 can be made of EVA foam.
[0048] As shown in Figure 17, the tab 322 of the single battery 32 includes a third connecting portion 3221 and a fourth connecting portion 3222. The fourth connecting portion 3222 of the tab 322 is connected to the battery cell in the single battery 32 through the third connecting portion of the tab 322. The third connecting portion 3221 and the fourth connecting portion 3222 are both sheet-shaped. The fourth connecting portion 3222 is vertically connected to the third connecting portion 3221, that is, the sheet-shaped tab 322 is bent 90° to form the third connecting portion 3221 and the fourth connecting portion 3222. The fourth connecting portion 3222 is parallel to the end face of the single battery 32, and the fourth connecting portion 3222 is connected to the first connecting portion 331. By setting the fourth connecting portion 3222 parallel to the end face of the single battery 32 and connecting the fourth connecting portion 3222 to the first connecting portion 331, bending the connection position between the pole tab 322 and the first connecting member 33 can be avoided, thereby reducing the difficulty of connecting the pole tab 322 and the first connecting member 33 and the influence of bending on the connection effect, thereby improving the reliability of the connection between the pole tab 322 and the first connecting member 33.
[0049] In this embodiment, the first connection portion 331 and the tab 322 are welded together, and the second connection portion 332 and the second connector 34 are also welded together. Other welding methods such as ultrasonic welding and laser welding may also be used.
[0050] The single cell 32 usually has two tabs 322, one of which serves as the positive electrode and the other serves as the negative electrode. The two tabs 322 of the single cell 32 shown in Figures 1 to 6 are located on the same side of the single cell 32, which is recorded as a single-end tab battery. The tabs 322 of the single-end tab battery extend from the same end face of the single cell 32. The two tabs 322 of the single cell 32 shown in Figures 7 to 11 are distributed on both sides of the single cell 32, which is recorded as a double-end tab battery. The tabs 322 of the double-end tab battery extend from both end faces of the single cell 32.
[0051] 1 to 6 , for a single-ended tab battery, a battery module 3 can be produced by the following steps:
[0052] Step 101, referring to FIG. 1 , the (positive) tab 322 of one single battery cell 32 (single-ended tab battery) and the (negative) tab 322 of another single battery cell 32 are connected and assembled by ultrasonic welding using a first connector 33 (nickel sheet);
[0053] Step 102, referring to FIG. 2, based on FIG. 1, the tabs 322 of the two single cells 32 (single-ended tab batteries) are bent 90°, the two single cells 32 (single-ended tab batteries) are stacked, and a first buffer 36 is placed between the two single cells 32 (single-ended tab batteries), and then the first connector 33 (nickel sheet) is bent 90° to form an L-shape; this step forms a battery assembly;
[0054] Step 103 , referring to FIG. 3 , stack multiple battery assemblies shown in FIG. 2 , ensuring that a first buffer 36 is placed between every two single batteries 32 (single-end tab batteries);
[0055] Step 104, referring to FIG4, based on FIG3, according to the design requirements of series and parallel connection of the circuit in the battery module 3, the battery assembly shown in FIG2 is connected through the second connector 34 using the second connector 34, and the second connector 34 (nickel sheet) is connected to the second connecting portion 332 of the first connector 33 (nickel sheet) by ultrasonic welding;
[0056] Step 105, referring to FIG. 5 , based on FIG. 4 , the excess portion of the first connecting member 33 (nickel sheet) is cut off, and then the first connecting member 33 (nickel sheet) is further bent 90° to form a bent portion 333 of the first connecting member 33. At this time, the first connecting portion 331 and the second connecting portion 332 on the first connecting member 33 are overlapped;
[0057] Step 106 , referring to FIG. 6 , based on FIG. 5 , the support members 35 are filled into the gaps between the single cells 32 .
[0058] 7 to 11 , for a double-ended tab battery, a battery module 3 can be produced by the following steps:
[0059] Step 201, referring to FIG. 7 , ultrasonically weld the (positive) tab 322 and the (negative) tab 322 of the single battery 32 (double-ended tab battery) to the two first connectors 33 (nickel sheets);
[0060] Step 202, referring to FIG. 8 , based on FIG. 7 , the tab 322 is bent 90°;
[0061] Step 203 , referring to FIG. 9 , based on FIG. 8 , the first connecting member 33 (nickel sheet) is bent 90°;
[0062] Step 204, referring to FIG10 , stack multiple single cells 32 (double-ended tab batteries) and first connectors 33 shown in FIG9 , insert a first buffer 36 between every two single cells 32 (double-ended tab batteries), pad the grooves of the tabs 322 of the single cells 32 to the ultrasonic welding point of the tabs 322 , and then connect the multiple single cells 32 (double-ended tab batteries) using the second connector 34 (nickel sheet) according to the design requirements of the series and parallel circuits in the battery module 3 ;
[0063] Step 205 , referring to FIG. 11 : Based on FIG. 10 , the first connecting member 33 (nickel sheet) is bent 90°. At this time, the first connecting portion 331 and the second connecting portion 332 on the first connecting member 33 are overlapped.
[0064] 12 to 16 , this embodiment further provides a battery pack comprising a housing 1 and a battery module 3 according to any of the embodiments. The battery module 3 is disposed within the housing 1, with the side surfaces of the battery module 3 abutting against the inner wall of the housing 1. The housing 1 in this embodiment is referred to as the restraining structure mentioned in the embodiment. Since the battery module 3 is a rectangular parallelepiped, the design difficulty of the restraining structure can be reduced. Specifically, a planar structure within the housing can be used to restrain the battery module 3, reducing the design difficulty of the battery pack and thereby reducing costs.
[0065] The battery pack also includes a conductor 210 and a second buffer 2. The housing 1 is equipped with a current output socket 13. The battery module 3 has a power transmission side 31 (formed by the end surfaces of multiple battery cells 32). A second connector 34 is mounted on the power transmission side 31. The ends of the conductor 210 are connected to the current output socket 13 and the second connector 34, respectively. The second buffer 2 is positioned between the power transmission side 31 and the inner wall of the housing 1. The second buffer 2 absorbs expansion of the battery cells 32, thereby reducing compression on the conductors and improving the reliability of the battery pack. The second buffer 2 can be made of EVA foam.
[0066] The second buffer member 2 is provided with a wiring groove 21, and the wire 210 is arranged in the wiring groove 21. By providing the wiring groove 21, the compression of the wire 210 by the single battery 32 in the collision state can be further reduced, thereby improving the reliability of the battery pack.
[0067] 15 , the second buffer member 2 is further provided with a weight-reducing hole 22. By providing the weight-reducing hole 22, the weight of the second buffer member 2 can be reduced, thereby reducing the weight of the entire battery pack and achieving a lightweight design of the battery pack.
[0068] Multiple battery modules 3 are arranged within the housing 1. Referring to Figure 16 , the housing 1 is also provided with multiple spacers 12. The spacers 12 are fixed to the inner wall of the housing 1. A spacer 12 is provided between two adjacent battery modules 3, and the spacers 12 are in contact with the sides of the battery modules 3. The spacers 12 divide the space within the housing 1, individually restraining each battery module 3 and preventing direct contact between the battery modules 3. This improves the restraint effect on the battery modules 3, thereby enhancing the reliability of the battery pack.
[0069] In this embodiment, the box body 1 is a rectangular parallelepiped, and is formed by six splicing plates 11 spliced together and enclosed. The partition plates 12 are fixedly connected to the corresponding splicing plates 11 respectively.
Claims
1. A battery module comprising: A plurality of single cells (32), a plurality of first connecting members (33), and a plurality of second connecting members (34); The single battery (32) has an end surface, and the end surface is provided with a tab (322); The first connecting member (33) and the second connecting member (34) are both flexible members. The first connecting member (33) comprises a first connecting portion (331), a second connecting portion (332) and a bent portion (333). The first connecting portion (331) and the second connecting portion (332) are both sheet-shaped. Two ends of the bent portion (333) are respectively connected to the first connecting portion (331) and the second connecting portion (332). A plurality of the single cells (32) are stacked together, the first connecting portion (331) connects the tabs (322) of two adjacent single cells (32), the second connecting member (34) is sheet-shaped, the second connecting member (34) connects the second connecting portions (332) of two adjacent first connecting members (33), and the second connecting member (34), the first connecting portion (331) and the second connecting portion (332) are stacked on the end surface of the single cell (32).
2. The battery module according to claim 1, further comprising a support member (35), wherein the single battery (32) comprises a core portion (323) and an edge portion (321), the thickness of the core portion (323) is greater than the thickness of the edge portion (321), and the support member (35) is provided between the edge portions (321) of two adjacent single batteries (32), and a side surface of the support member (35) is in contact with at least one of the first connector (33) and the second connector (34).
3. The battery module according to claim 2, wherein: The support member (35) is a flexible support block.
4. The battery module according to claim 1, wherein: A first buffer member (36) is provided between two adjacent single batteries (32), and the first buffer member (36) is in a sheet shape.
5. The battery module according to claim 1, wherein: The tab (322) comprises a third connecting portion (3221) and a fourth connecting portion (3222); the fourth connecting portion (3222) is connected to the battery cell in the single battery (32) via the third connecting portion (3221); the third connecting portion (3221) and the fourth connecting portion (3222) are both sheet-shaped; the fourth connecting portion (3222) is vertically connected to the third connecting portion (3221); the fourth connecting portion (3222) is parallel to the end face of the single battery (32); and the fourth connecting portion (3222) is connected to the first connecting portion (331).
6. A battery pack comprising a box (1) and a battery module (3) according to any one of claims 1 to 5, wherein the battery module (3) is arranged in the box (1), and the side surface of the battery module (3) is in contact with the inner wall of the box (1).
7. The battery pack according to claim 6, further comprising a wire (210) and a second buffer member (2), the box (1) being provided with a current output seat (13), the battery module (3) having a power transmission side (31), the second connecting member (34) of the battery module (3) being provided on the power transmission side (31), the two ends of the wire (210) being connected to the current output seat (13) and the second connecting member (34) respectively, and the second buffer member (2) being provided between the power transmission side (31) and the inner wall of the box (1).
8. The battery pack according to claim 7, wherein: A wiring groove (21) is provided in the second buffer member (2), and the wire (210) is provided in the wiring groove (21).
9. The battery pack according to claim 7, wherein: The second buffer member (2) is provided with a weight-reducing hole (22).
10. The battery pack according to claim 6, wherein: There are a plurality of battery modules (3), and a plurality of partition plates (12) are further provided in the box body (1). The partition plates (12) are fixed to the inner wall of the box body (1), and the partition plates (12) are provided between two adjacent battery modules (3), and the partition plates (12) are in contact with the side surfaces of the battery modules (3).