Battery top cover assembly, secondary battery and battery module

Abstract

The invention relates to the technical field of batteries, in particular to a battery top cover assembly, a secondary battery and a battery module, a terminal hole is formed in a top cover plate, an electrode assembly comprises electrode terminals serving as a positive electrode and a negative electrode, and a sealing assembly is arranged between the electrode assembly and the top cover plate; the electrode terminal comprises a main body at the top and an extension end, the main body adopts an inverted circular truncated cone-shaped structure, the top of the main body is flush with the top cover plate, the top of the main body is welded with a connecting piece of the battery module to form a welding area, a sealing assembly is annularly distributed on the extension end, and a sealing groove is formed in a terminal hole; the sealing assembly comprises a first sealing ring and a second sealing ring, a shape memory material is arranged in the center of the second sealing ring, and the shape memory material deforms in response to increase or decrease of temperature to achieve switching between a sealing state and a sealing release state. The electrode assembly has the functions of a battery electrode, liquid injection and pressure relief, the failure rate of the whole battery is reduced, and the safety of the whole battery and the battery module is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery top cover assembly, a secondary battery and a battery module. BACKGROUND

[0002] At present, the secondary batteries of the battery module are mostly connected by the connecting sheet, and the prior art usually uses the laser penetration welding method to fix the connecting sheet to the electrode terminal on the top cover plate. In order to connect with the electrode assembly inside the secondary battery, the electrode terminal needs to pass through the top cover plate, and in order to ensure the sealing performance of the secondary battery, a sealing member needs to be arranged between the electrode terminal and the top cover plate. If the sealing member is arranged inside the top cover plate (that is, inside the secondary battery), the sealing member is easy to be corroded by the electrolyte, which affects the sealing performance of the sealing member. In the prior art, the sealing member is also arranged outside the top cover plate, but when the connecting sheet is welded, the welding area is strip-shaped, and in order to increase the flow area, the welding area covers the sealing member, which will make the heat generated by welding directly transmitted to the sealing member through the electrode terminal, causing the sealing member to be aged and failed due to high temperature.

[0003] Chinese patent CNCN110034269B provides a battery top cover assembly, a secondary battery and a battery module. The battery top cover assembly includes a top cover plate, a first electrode terminal and a first sealing member. The top cover plate has a first terminal hole. The first electrode terminal has a first protruding portion protruding to the upper side of the top cover plate and a first base portion connected to the bottom surface of the first protruding portion, the first base portion extends into the first terminal hole, and the cross-sectional area of the first protruding portion is larger than that of the first terminal hole. The first sealing member has a first body portion arranged between the first protruding portion and the top cover plate, and the first body portion has a first through hole for the first base portion to pass through. The first protruding portion is used for welding with the first connecting sheet and forming a fusion zone, and the projection of the fusion zone is located in the first through hole. The secondary battery includes a shell, a battery top cover assembly and an electrode assembly. The battery module includes a first connecting sheet and a plurality of secondary batteries, and the first connecting sheet is welded to the first protruding portion of the first electrode terminal of the battery top cover assembly of the secondary battery and forms a fusion zone.

[0004] The prior art changes the shape of the electrode terminal, sets the protruding portion protruding above the top cover plate to match the main body shape of the electrode terminal, and extends the heat transfer path during the welding process, so as to reduce the risk of high temperature burning out the sealing assembly between the electrode terminal and the top cover plate. However, the design of increasing the thickness of the single battery electrode terminal not only increases the thickness of the entire battery top cover assembly, but also increases the installation difficulty through the multi-segment sealing member, greatly increasing the manufacturing cost and the rejection rate of the battery top cover. SUMMARY

[0005] In order to overcome the problems in the prior art, the present application provides a battery top cover assembly, a secondary battery and a battery module.

[0006] The application provides a battery top cover assembly, a secondary battery and a battery module. The application provides a battery top cover assembly, a secondary battery and a battery module.

[0007] By adopting the technical scheme, the terminal hole formed in the top cover plate is used for mounting the electrode assembly, and the sealing assembly is arranged between the electrode assembly and the top cover plate to seal the battery. Specifically, the electrode terminal in the electrode assembly adopts the inverted circular truncated cone structure and the extension end at the bottom to be connected with the top cover plate, the first sealing ring of the sealing assembly arranged at the junction of the main body and the extension end can be away from the fusion zone diffused from the center of the top of the main body to the periphery, and the first sealing ring can be used as a heat transfer path during the extension welding process to reduce the risk of the first sealing ring being burned out. The structure makes the top of the terminal assembly flush with the top cover plate, so that the appearance of the battery cell is more neat and smooth, and the battery cell is convenient to integrate into various devices. In addition, the flush electrode can reduce the risk of accidental contact between the electrode and external objects and the possibility of short circuit. The second sealing ring is arranged between the periphery of the extension end and the terminal hole, the shape memory material is arranged in the second sealing ring, and the second sealing ring can be switched between the sealing state and the unsealed state between the terminal hole and the extension end by the shape memory material responding to the temperature change.

[0008] Preferably, the sealing groove in the terminal hole includes a first groove body at the junction of the main body and the extension end and a second groove body corresponding to the side wall of the extension end, and the sealing assembly and the sealing groove are in interference fit.

[0009] By adopting the technical scheme, the two sealing grooves in the terminal hole and the sealing assembly are in interference fit, so as to ensure the sealing property of the battery top cover assembly.

[0010] Preferably, the first sealing ring adopts a sealing ring with a circular cross section, the first groove body adopts a semicircular groove body that can accommodate the sealing ring, and the abutting surface of the electrode terminal and the first sealing ring adopts an inclined plane.

[0011] By adopting the above technical solution, the first sealing ring adopts a sealing ring with a circular cross section, the first groove body adopts a semicircular groove body that can accommodate the sealing ring, and the abutting surface of the electrode terminal and the first sealing ring adopts an inclined plane. When high-temperature and high-pressure gas is generated due to a fault in the battery, the shape memory material in the second sealing ring is heated to release its sealing state, so that the electrode terminal is pushed out of the top cover plate under the action of pressure to release pressure.

[0012] Preferably, the second sealing ring adopts a sealing ring with a rectangular cross section, and a plurality of sealing protrusions are arranged on the inner side of the sealing ring. The second groove body adopts a rectangular groove that is matched with the sealing ring. The abutting surface of the electrode terminal and the second sealing ring adopts a sealing groove that is matched with the sealing protrusion.

[0013] Preferably, the top cover plate includes a detachably connected top plate and an insulating cover plate. An insulating mounting portion is mounted on the insulating cover plate. The insulating mounting portion is connected to the shape memory material of the second sealing ring and a conductive block at the top thereof through a wire. The insulating mounting portion penetrates the top plate and is flush with the top plate.

[0014] Preferably, an insulating cover body is mounted on the conductive block of the insulating mounting portion. The insulating cover body is rotationally connected to the insulating mounting portion. A ring-shaped water blocking groove is arranged around the insulating cover body.

[0015] Preferably, the connection between the top plate and the insulating cover plate is located between the first sealing ring and the second sealing ring.

[0016] By adopting the above technical solution, the second sealing ring adopts a sealing ring with a rectangular cross section. The shape memory material at the center is connected to the conductive block through an external power source. The conductive block is connected to the shape memory material through a wire. The shape memory material is heated by electricity. After being heated, the shape memory material shrinks. The electrode terminal is installed in the terminal hole of the top cover plate. After installation, the external power source is disconnected. After the temperature of the shape memory material decreases, the expansion of the shape memory material drives the sealing protrusions on the inner side of the second sealing ring to cooperate with the sealing grooves on the electrode terminal to seal, thereby ensuring the stability of the sealing structure. The top cover plate adopts a detachable top plate and an insulating cover plate. The insulating mounting portion mounted on the insulating cover plate penetrates the top plate. The conductive block on the insulating mounting portion is connected to and controls the second sealing ring on two electrodes of a single battery cell through a wire. An insulating cover plate is arranged on the conductive block of the insulating mounting portion. In a non-installed state, the conductive block can be protected by the insulating cover plate. A ring-shaped water blocking groove is arranged around the conductive block to prevent water from entering the conductive block of the battery cell and causing short circuit and corrosion.

[0017] Preferably, the shape memory material includes a shape memory alloy, a shape memory polymer and a liquid crystal elastomer.

[0018] By adopting the above technical solution, the shape memory alloy, the shape memory polymer and the liquid crystal elastomer all have the shape memory function and can recover from the temporary shape to the original shape under specific conditions such as temperature, humidity, light and the like.

[0019] A secondary battery includes a shell, an electrolyte and the battery top cover assembly, the shell includes a containing cavity containing the electrolyte and an opening communicating with the containing cavity, and the battery top cover assembly covers the opening.

[0020] A battery module includes the secondary battery.

[0021] In summary, the present application has at least one of the following beneficial technical effects: 1. The electrode terminal is installed in the terminal hole in the top cover plate through the sealing assembly, because the electrode assembly is a necessary structure of the battery, the electrolyte can be injected through the terminal hole, avoiding opening the injection hole on the battery top cover, not only avoiding the injection hole occupying the capacity of the battery, but also simplifying the structure of the battery, simplifying the processing steps and reducing the cost; 2. The first sealing ring and the second sealing ring are arranged between the terminal holes of the electrode terminal top cover plate to seal, the shape memory material arranged in the second sealing ring is sealed and installed through the external power supply of the electrode terminal, and when high temperature and high pressure gas occurs in the battery, the shape memory material in the second sealing ring can be heated to remove its sealing state, so that the electrode terminal with a main body of an inverted circular truncated cone is pushed out of the terminal hole under the action of pressure to release pressure; 3. The electrode assembly in the battery top cover assembly has the functions of battery electrode, liquid injection and pressure relief, greatly simplifies the structure of the electrode assembly, reduces the overall failure rate of the battery, and improves the overall safety of the battery and the battery module. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural schematic diagram of the battery top cover assembly; Figure 2 is a structural schematic diagram of the secondary battery; Figure 3 is a structural schematic diagram of the battery module.

[0023] Explanation of reference signs: 1, top cover plate; 11, terminal hole; 111, sealing groove; 1111, first groove body; 1112, second groove body; 12, top plate; 13, insulating cover plate; 131, insulating mounting portion; 132, wire; 133, conductive block; 134, insulating cover body; 135, annular water retaining groove; 2, electrode assembly; 21, electrode terminal; 211, main body; 212, extension end; 213, sealing groove; 3, sealing assembly; 31, first sealing ring; 32, second sealing ring; 321, shape memory material; 322, sealing protrusion; 4, shell; 5, accommodating cavity; 6, opening. DETAILED DESCRIPTION

[0024] The following description will be made in conjunction with the accompanying drawings. Figures 1-3 The application is further described in detail.

[0025] Embodiment 1 The embodiment of the application discloses a battery top cover assembly.

[0026] Reference is made to Figure 1A battery top cover assembly, comprising a top cover plate 1, the top cover plate 1 is provided with a terminal hole 11 for penetrating an electrode assembly 2, the electrode assembly 2 comprises electrode terminals 21 as positive and negative electrodes respectively, wherein the electrode assembly 2 is provided with a sealing assembly 3 between the electrode assembly 2 and the top cover plate 1; the electrode assembly 2, the electrode terminals 21 of the electrode assembly 2 comprise a main body 211 at the top and an extension end 212 at the bottom of the main body 211, wherein the main body 211 adopts an inverted circular truncated cone structure and the top of the main body 211 is flush with the top cover plate 1, and the top of the main body 211 is welded with a connecting sheet of a battery module and forms a fusion zone, the extension end 212 is provided with the sealing assembly 3 in a ring shape, and the terminal hole 11 is provided with a corresponding sealing groove 111; the sealing assembly 3, the sealing assembly 3 comprises a first sealing ring 31 located at the connection between the top of the extension end 212 and the main body 211 and a second sealing ring 32 located at the opening 6 of the bottom of the terminal hole 11 close to the extension end 212, wherein the second sealing ring 32 is provided with a shape memory material 321 at the center, and the shape memory material 321 deforms in response to an increase or decrease in temperature, so that the second sealing ring 32 can switch between a sealed state and an unsealed state between the terminal hole 11 and the extension end 212. The terminal hole 11 provided on the top cover plate 1 is used to install the electrode assembly 2, wherein the electrode assembly 2 and the top cover plate 1 are connected through the sealing assembly 3 to realize the sealing of the battery. Specifically, the electrode terminals 21 in the electrode assembly 2 adopt an inverted circular truncated cone structure and the extension end 212 at the bottom is connected with the top cover plate 1, wherein the first sealing ring 31 of the sealing assembly 3 located at the junction of the main body 211 and the extension end 212 can be away from the fusion zone which spreads from the center of the top of the main body 211 to the periphery, which plays a heat transfer path during the extension welding process, reduces the risk of the first sealing ring 31 being burned out, and the structure makes the top of the terminal assembly flush with the top cover plate 1, which makes the appearance of the battery cell more neat and smooth, and is convenient for integration into various devices, and the flush electrode can reduce the risk of accidental contact between the electrode and external objects and reduce the possibility of short circuit. The sealing assembly 3 is also provided with a second sealing ring 32 between the periphery of the extension end 212 and the terminal hole 11, the second sealing ring 32 is provided with a shape memory material 321, the shape memory material 321 adopts a shape memory alloy, and the second sealing ring 32 can switch between a sealed state and an unsealed state between the terminal hole 11 and the extension end 212 by the shape memory material 321 responding to temperature changes.

[0027] Referring to Figure 1 The sealing groove 111 in the terminal hole 11 comprises a first groove body 1111 located at the junction of the main body 211 and the extension end 212 and a second groove body 1112 corresponding to the side wall of the extension end 212, and the sealing assembly 3 and the sealing groove 111 adopt an interference fit. The interference fit between the two sealing grooves 111 in the terminal hole 11 and the sealing assembly 3 ensures the sealing property of the battery top cover assembly.

[0028] Referring toFigure 1 , the first sealing ring 31 adopts a sealing ring with a circular cross section, the first groove body 1111 adopts a semicircular groove body matched with the sealing ring, and the abutting surface between the electrode terminal 21 and the first sealing ring 31 adopts an inclined plane. The first sealing ring 31 adopts a sealing ring with a circular cross section, the first groove body 1111 adopts a semicircular groove body matched with the sealing ring, and the abutting surface between the electrode terminal 21 and the first sealing ring 31 adopts an inclined plane. When high-temperature and high-pressure gas is generated due to a fault in the battery, the shape memory material 321 in the second sealing ring 32 is heated to release its sealing state, so that the electrode terminal 21 is pushed out of the top cover plate 1 under the action of pressure to release pressure.

[0029] Referring to Figure 1 , the second sealing ring 32 adopts a sealing ring with a rectangular cross section, and a plurality of sealing protrusions 322 are arranged on the inner side of the sealing ring. The second groove body 1112 adopts a rectangular groove matched with the sealing ring, and the abutting surface between the electrode terminal 21 and the second sealing ring 32 adopts a sealing groove 213 matched with the sealing protrusions 322. The top cover plate 1 includes a detachably connected top plate 12 and an insulating cover plate 13, and the insulating cover plate 13 is provided with an insulating mounting portion 131. The insulating mounting portion 131 is connected to the shape memory material 321 of the second sealing ring 32 and a conductive block 133 at the top of the insulating mounting portion 131 through a wire 132. The insulating mounting portion 131 penetrates through the top plate 12 and is flush with the top plate 12. An insulating cover 134 is arranged on the conductive block 133 of the insulating mounting portion 131. The insulating cover 134 is rotationally connected to the insulating mounting portion 131, and a ring-shaped water blocking groove 135 is arranged around the insulating cover 134. The connection between the top plate 12 and the insulating cover plate 13 is located between the first sealing ring 31 and the second sealing ring 32. The second sealing ring 32 adopts a sealing ring with a rectangular cross section. The shape memory material 321 in the center of the sealing ring is connected to the conductive block 133 through an external power source. The conductive block 133 is connected to the shape memory material 321 through the wire 132. The shape memory material 321 is heated by electricity. After being heated, the shape memory material 321 shrinks. The electrode terminal 21 is installed in the terminal hole 11 of the top cover plate 1. After installation, the external power source is disconnected. After the temperature of the shape memory material 321 decreases, the expansion of the shape memory material 321 drives the sealing protrusions 322 on the inner side of the second sealing ring 32 to cooperate with the sealing groove 213 on the electrode terminal 21 to seal, thereby ensuring the stability of the sealing structure. The top cover plate 1 adopts a detachable top plate 12 and an insulating cover plate 13. The insulating mounting portion 131 mounted on the insulating cover plate 13 penetrates through the top plate 12. The conductive block 133 on the insulating mounting portion 131 is connected to and controls the second sealing ring 32 on two electrodes of a single cell through the wire 132. The conductive block 133 on the insulating mounting portion 131 is provided with the insulating cover plate 13. In a non-installed state, the conductive block 133 can be protected by the insulating cover plate 13. The ring-shaped water blocking groove 135 is arranged around the conductive block 133 to avoid water entering the conductive block 133 on the cell to cause short circuit and corrosion.

[0030] Embodiment 2 The embodiment of the present application discloses a secondary battery.

[0031] With reference to Figure 2 , including the shell 4, electrolyte and the battery top cover assembly in embodiment 1, the shell 4 includes the solution cavity accommodating electrolyte and the opening 6 communicated with the accommodating cavity 5, and the battery top cover assembly covers the opening 6.

[0032] Embodiment 3 The embodiment of the present application discloses a battery module.

[0033] With reference to Figure 3 , including the secondary battery in embodiment 2.

[0034] The above are all preferred embodiments of the present application, not limited to the protection scope of the present application, so: all equivalent changes made according to the structure, shape, principle of the present application should be covered in the protection scope of the present application.

Claims

1. A battery top cover assembly, characterized in that: include The top cover plate (1) has a terminal hole (11) for penetrating the electrode assembly (2). The electrode assembly (2) includes electrode terminals (21) as positive and negative electrodes respectively. A sealing assembly (3) is provided between the electrode assembly (2) and the top cover plate (1). The electrode assembly (2) has an electrode terminal (21) comprising a top body (211) and an extension end (212) at the bottom of the body (211). The body (211) adopts an inverted frustum structure and the top of the body (211) is flush with the top cover plate (1). The top of the body (211) is welded to the connecting piece of the battery module to form a fusion zone. The extension end (212) has a ring-shaped distribution of sealing components (3) and a corresponding sealing groove (111) is provided in the terminal hole (11). The sealing assembly (3) includes a first sealing ring (31) located at the connection between the top of the extension end (212) and the main body (211) and a second sealing ring (32) located at the bottom opening (6) of the extension end (212) near the terminal hole (11). The second sealing ring (32) is provided with a shape memory material (321) at its center. The shape memory material (321) deforms in response to the increase or decrease of temperature so that the second sealing ring (32) can switch between a sealing state and a desealing state between the terminal hole (11) and the extension end (212).

2. The battery top cover assembly according to claim 1, characterized in that: The sealing groove (111) in the terminal hole (11) includes a first groove (1111) located at the junction of the main body (211) and the extension end (212) and a second groove (1112) corresponding to the side wall of the extension end (212), and the sealing assembly (3) and the sealing groove (111) are both interference fit.

3. A battery top cover assembly according to claim 2, characterized in that: The first sealing ring (31) is a sealing ring with a circular cross-section, and the first groove (1111) is a semi-circular groove adapted to it, wherein the contact surface between the electrode terminal (21) and the first sealing ring (31) is an inclined plane.

4. A battery top cover assembly according to claim 2, characterized in that: The second sealing ring (32) is a rectangular sealing ring with a plurality of sealing protrusions (322) on the inner side of the sealing ring. The second groove (1112) adopts a matching sealing groove (213), wherein the contact surface between the electrode terminal (21) and the second sealing ring (32) adopts a sealing groove (213) that matches the sealing protrusions (322).

5. A battery top cover assembly according to claim 1, characterized in that: The top cover plate (1) includes a detachably connected top plate (12) and an insulating cover plate (13). An insulating mounting part (131) is installed on the insulating cover plate (13). The insulating mounting part (131) is connected to the shape memory material (321) of the second sealing ring (32) and its top conductive block (133) through a wire (132). The insulating mounting part (131) penetrates the top plate (12) and is flush with the top plate (12).

6. A battery top cover assembly according to claim 5, characterized in that: The conductive block (133) of the insulating mounting part (131) is covered with an insulating cover (134), wherein the insulating cover (134) is rotatably connected to the insulating mounting part (131), and an annular water-blocking groove (135) is provided around the insulating cover (134).

7. A battery top cover assembly according to claim 6, characterized in that: The connection between the top plate (12) and the insulating cover plate (13) is displaced between the first sealing ring (31) and the second sealing ring (32).

8. A battery top cover assembly according to claim 1, characterized in that: The shape memory material (321) includes shape memory alloys, shape memory polymers, and liquid crystal elastomers.

9. A secondary battery, characterized in that, The battery includes a housing (4), an electrolyte, and a battery top cover assembly according to any one of claims 1 to 8, wherein the housing (4) includes a receiving cavity (5) for containing the electrolyte and an opening (6) communicating with the receiving cavity (5), and the battery top cover assembly covers the opening (6).

10. A battery module, characterized in that, Includes the secondary battery as described in claim 9.

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