Secondary battery and battery module

Abstract

The utility model discloses a secondary battery and a battery module. The secondary battery comprises a positive electrode assembly component and a battery shell, an opening is formed in the positive electrode side of the battery shell and is matched with the positive electrode assembly component; the non-positive side of the battery shell is sealed; a plurality of concave parts are arranged on the positive electrode opposite side of the battery shell; the negative electrode welding plate is connected with the negative electrode plate; the positive electrode assembly component comprises an upper pole, an upper sealing gasket, a positive electrode side welding plate, a lower sealing gasket and a lower pole, the upper pole, the upper sealing gasket, the positive electrode side welding plate, the lower sealing gasket and the lower pole are sequentially arranged from top to bottom, and the middle of the upper pole is concave to form a concave part; the upper sealing gasket is arranged between the upper pole and the positive electrode side welding plate, and the positive electrode side welding plate is matched with the opening of the battery shell; the lower sealing gasket is arranged between the positive electrode side welding plate and the lower pole, and the upper sealing gasket and the lower sealing gasket are matched to form an insulating sealing piece; the upper sealing gasket, the positive electrode side welding plate and the lower sealing gasket are all provided with through holes matched with the inner concave parts; the lower pole is arranged between the lower sealing gasket and the positive plate, and the bottom end of the lower pole is connected with the positive plate; the inner concave part of the upper pole sequentially penetrates through the through holes of the upper sealing gasket, the positive electrode side welding plate and the lower sealing gasket, and the bottom end of the inner concave part is connected with the top end of the lower pole.

Description

Technical Field

[0001] The utility model relates to the technical field of secondary batteries, and particularly relates to a secondary battery and a battery module. Background Art

[0002] A common secondary battery is a nickel-metal hydride battery (Ni-MH). The positive active material of the nickel-metal hydride battery is Ni(OH)2, the negative active material is a metal hydride, also called a hydrogen storage alloy (the electrode is called a hydrogen storage electrode), and the electrolyte is a 6mol / L potassium hydroxide solution. The nickel-metal hydride battery has attracted more and more attention due to its excellent safety performance.

[0003] In the prior art, a secondary battery includes a positive electrode lead-out terminal (upper pole column), a metal battery case with an oblong or rectangular cross-sectional shape, an insulating and sealing assembly, a lower pole column, and current collector plates (positive electrode plate, negative electrode plate) to accommodate the electrode plates and the electrolyte in the battery case. Usually, the positive electrode lead-out terminal is fixed on the long side surface of the case. A step is formed by inward concavity in the middle of the positive electrode lead-out terminal. The step passes through the opening of the battery case and is connected to the positive electrode plate. The opposite side of the battery case relative to the lead-out terminal is a negative electrode welding plate. After the battery core is assembled, the negative electrode welding plate and the battery case are hermetically welded. There are the following problems: (1) Since the welding area of the flat part of the step of the lead-out terminal is small, the welding quality is poor, affecting its large-current charge and discharge performance; (2) The poor welding quality leads to poor electrical conductivity and sealing performance of the battery, and the electrolyte leaks; (3) During the battery assembly process, first, the positive electrode lead-out terminal, the battery case, the insulating and sealing assembly, and the lower pole column are fixed by using a tooling, the positive electrode lead-out terminal and the lower pole column are welded by using laser welding, then the stacked battery cores are placed into the battery case, and the positive electrode lead-out terminal and the positive electrode plate are welded; finally, the negative electrode welding plate and the negative electrode plate are welded, and the negative electrode welding plate and the battery case are sealed. Its production process is complex, and in the subsequent production process, it is easy to cause the positive electrode lead-out terminal to deviate from the center position, resulting in a short circuit between the positive and negative electrodes, generating potential safety hazards, increasing the scrap rate of the battery, and increasing the production cost. Summary of the Utility Model

[0004] Aiming at the deficiencies of the prior art, the purpose of the utility model is to provide a secondary battery and a battery module to solve the technical problems in the background art.

[0005] The utility model provides a secondary battery, which includes a positive electrode assembly member and a battery case;

[0006] An opening is provided on the positive electrode side of the battery case, and the opening is adapted to the positive electrode assembly member; the non-positive electrode sides of the battery case are all hermetically arranged;

[0007] A plurality of recessed parts are provided on the side opposite to the positive electrode of the battery case for a negative electrode welding plate, and the negative electrode welding plate is connected to the negative electrode plate;

[0008] The positive electrode assembly member includes an upper pole column, an upper gasket, a positive electrode side welding plate, a lower gasket, and a lower pole column. The upper pole column, the upper gasket, the positive electrode side welding plate, the lower gasket, and the lower pole column are arranged in sequence from top to bottom. An inner concave portion is formed in the middle of the upper pole column;

[0009] The upper gasket is arranged between the upper pole column and the positive electrode side welding plate. The positive electrode side welding plate is adapted to the opening of the battery case for sealing the battery case. The lower gasket is arranged between the positive electrode side welding plate and the lower pole column. The upper gasket and the lower gasket cooperate to form an insulating seal to prevent the upper pole column, the lower pole column from contacting the positive electrode side welding plate. The upper gasket, the positive electrode side welding plate, and the lower gasket are all provided with through holes adapted to the inner concave portion;

[0010] The lower pole column is arranged between the lower gasket and the positive electrode plate, and the bottom end of the lower pole column is connected to the positive electrode plate. The inner concave portion of the upper pole column sequentially passes through the through holes of the upper gasket, the positive electrode side welding plate, and the lower gasket, and the bottom end of the inner concave portion is connected to the top end of the lower pole column.

[0011] Advantages of the above technical solution: By improving the battery case, an opening is provided on the positive electrode side of the battery case, and the opening is adapted to the positive electrode assembly member. The non-positive electrode side of the battery case is hermetically sealed, improving the sealing performance of the secondary battery. By improving the positive electrode assembly member, the upper pole column, the upper gasket, the positive electrode side welding plate, the lower gasket, and the lower pole column are assembled to obtain the positive electrode assembly member, and then the lower pole column and the positive electrode plate are welded, improving the welding quality and the high current charge and discharge capacity of the battery.

[0012] Preferably, the inner concave portion of the upper pole column is fixed to the lower pole column by welding, and the bottom end of the lower pole column is fixed to the positive electrode plate by welding.

[0013] Preferably, the upper gasket includes a flat portion and a cylindrical portion. A first groove is provided on the upper surface of the flat portion, and a first protrusion adapted to the first groove is provided at the corresponding position on the lower surface of the upper pole column;

[0014] A second groove is provided on the lower surface of the lower gasket, and a second protrusion matching the second groove is provided at the corresponding position on the upper surface of the lower pole column;

[0015] A third groove is provided on the upper surface of the lower gasket, and the third groove is adapted to the bottom end of the cylindrical portion;

[0016] The upper gasket is clamped and fixed between the upper pole column and the positive electrode side welding plate, and the lower gasket is clamped and fixed between the lower pole column and the positive electrode side welding plate to form an insulating seal.

[0017] In a preferred embodiment, the upper surface of the lower terminal post is provided with a fourth groove, which is adapted to the lower gasket;

[0018] In the middle of the upper surface of the lower terminal post, there is a third protrusion, which is embedded in the through hole of the lower gasket.

[0019] In a preferred embodiment, the lower surface of the lower gasket is provided with a fourth protrusion, which is arranged along the outer edge of the lower terminal post.

[0020] In a preferred embodiment, the upper surface of the planar part is provided with a fifth protrusion, which is arranged along the outer edge of the upper terminal post.

[0021] Beneficial effects of the above technical solutions: By setting a multi-layer sealing structure, the sealing effect of the secondary battery is further improved, the problem of liquid leakage of the secondary battery is solved, the climbing path of the electrolyte is extended, and the probability of electrolyte climbing is reduced.

[0022] The present utility model further provides a battery module, which is composed of the secondary batteries connected in series and / or in parallel. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 is the battery case of the prior art;

[0025] Figure 2 is the schematic structural diagram of the battery case provided by the present utility model;

[0026] Figure 3 is the schematic structural diagram of the battery case provided by the present utility model;

[0027] Figure 4 is the schematic structural diagram of the secondary battery provided by the present utility model;

[0028] Figure 5 is the schematic structural diagram of the upper terminal post provided by the present utility model;

[0029] Figure 6 is the schematic structural diagram of the upper gasket provided by the present utility model;

[0030] Figure 7 is the schematic structural diagram of the positive side welding plate provided by the present utility model;

[0031] Figure 8 Schematic diagram of the lower gasket structure provided by the present utility model;

[0032] Figure 9 Schematic diagram of the lower pole column structure provided by the present utility model;

[0033] Figure 10 3D schematic diagram of the positive electrode assembly member provided by the present utility model;

[0034] Figure 11 Cross-sectional view of the positive electrode assembly member provided by the present utility model;

[0035] Figure 12 Schematic diagram of the positive electrode assembly member structure provided by the present utility model;

[0036] Figure 13 Cross-sectional structure diagram of the positive electrode assembly member provided by the present utility model;

[0037] Figure 14 Connection schematic diagram of the positive electrode assembly member and the positive electrode plate provided by the present utility model;

[0038] Figure 15 Connection schematic diagram of the positive electrode assembly member and the positive electrode plate provided by the present utility model;

[0039] Figure 16 Schematic diagram of the negative electrode welding plate and the negative electrode plate structures provided by the present utility model;

[0040] Explanation of reference numerals;

[0041] 1 - Positive electrode assembly member; 11 - Upper pole column; 111 - Concave part; 112 - First protrusion; 12 - Upper gasket; 121 - Plane part; 122 - Cylindrical part; 123 - First groove; 124 - Fifth protrusion; 13 - Positive electrode side welding plate; 14 - Lower gasket; 141 - Second groove; 142 - Third groove; 143 - Fourth protrusion; 15 - Lower pole column; 151 - Second protrusion; 152 - Fourth groove; 153 - Third protrusion;

[0042] 2 - Battery housing;

[0043] 3 - Negative electrode plate;

[0044] 4 - Positive electrode plate;

[0045] 5 - Welding position. Detailed implementation manners

[0046] In order to make the objectives, technical solutions and advantages of the present utility model clearer, the following further elaborates on the present utility model in conjunction with embodiments.

[0047] Embodiment 1

[0048] As Figures 2 to 15 shown, the present utility model provides a secondary battery, which includes a positive electrode assembly member 1 and a battery case 2;

[0049] An opening 21 is provided on the positive electrode side of the battery case 2, and the opening 21 is adapted to the positive electrode assembly member 1; the non-positive electrode sides of the battery case 2 are all hermetically arranged;

[0050] A plurality of recessed portions 22 are provided on the side opposite to the positive electrode of the battery case 2 for a negative electrode welding plate 23, and the negative electrode welding plate 23 is connected to a negative electrode plate 3;

[0051] The positive electrode assembly member 1 includes an upper pole column 11, an upper gasket 12, a positive electrode side welding plate 13, a lower gasket 14 and a lower pole column 15. The upper pole column 11, the upper gasket 12, the positive electrode side welding plate 13, the lower gasket 14 and the lower pole column 15 are arranged in sequence from top to bottom. An inner concave portion 111 is formed by inner concavity in the middle of the upper pole column 11;

[0052] The upper gasket 12 is arranged between the upper pole column 11 and the positive electrode side welding plate 13. The positive electrode side welding plate 13 is adapted to the opening 21 of the battery case for sealing the battery case; the lower gasket 14 is arranged between the positive electrode side welding plate 13 and the lower pole column 15. The upper gasket 12 and the lower gasket 14 cooperate to form an insulating seal to prevent the upper pole column 11, the lower pole column 15 from contacting the positive electrode side welding plate 13; through holes adapted to the inner concave portion 111 are provided on the upper gasket 12, the positive electrode side welding plate 13 and the lower gasket 14;

[0053] The lower pole column 15 is arranged between the lower gasket 14 and the positive electrode plate 4, and the bottom end of the lower pole column 15 is connected to the positive electrode plate 4; the inner concave portion 111 of the upper pole column sequentially passes through the through holes of the upper gasket 12, the positive electrode side welding plate 13 and the lower gasket 14, and the bottom end of the inner concave portion 111 is connected to the top end of the lower pole column 15.

[0054] In a specific embodiment, the inner concave portion 111 of the upper pole column is fixed to the lower pole column 15 by welding, and the bottom end of the lower pole column 15 is fixed to the positive electrode plate 4 by welding; for the first welding, the connection and fixation between the upper pole column 11 and the lower pole column 15 are realized, and for the second welding, the connection and fixation between the lower pole column 15 and the positive electrode plate 4 are realized.

[0055] In a specific embodiment, the upper gasket 12 includes a planar portion 121 and a cylindrical portion 122. A first groove 123 is provided on the upper surface of the planar portion 121, and a first protrusion 112 adapted to the first groove 123 is provided at the corresponding position on the lower surface of the upper pole column 11;

[0056] The lower surface of the lower gasket 14 is provided with a second groove 141, and a second protrusion 151 matching the second groove 141 is provided at the corresponding position on the upper surface of the lower pole 15;

[0057] The upper surface of the lower gasket 14 is provided with a third groove 142, and the third groove 142 is adapted to the bottom end of the cylindrical portion 122;

[0058] The upper gasket 12 is clamped and fixed between the upper pole 11 and the positive side welding plate 13, and the lower gasket 14 is clamped and fixed between the lower pole 15 and the positive side welding plate 13 to form an insulating seal.

[0059] In a specific embodiment, the upper surface of the lower pole 15 is provided with a fourth groove 152, and the fourth groove 152 is adapted to the lower gasket 14;

[0060] The middle of the upper surface of the lower pole 15 is provided with a third protrusion 153, and the third protrusion 153 is embedded in the through hole of the lower gasket 14.

[0061] In a specific embodiment, the lower surface of the lower gasket 14 is provided with a fourth protrusion 143, and the fourth protrusion 143 is arranged on the outer edge of the lower pole 15.

[0062] In a specific embodiment, the upper surface of the planar portion 121 is provided with a fifth protrusion 124, and the fifth protrusion 124 is arranged on the outer edge of the upper pole 11. By setting a multiple sealing structure, the sealing effect of the secondary battery is further improved, the problem of liquid leakage of the secondary battery is solved, the creepage path of the electrolyte is extended, and the probability of electrolyte creepage is reduced.

[0063] In a specific embodiment, the secondary batteries are connected in series and / or in parallel to form a battery module.

[0064] The production process of the above secondary battery includes the following steps:

[0065] (1) Fabricating the positive electrode assembly component: Fixing the upper pole, the upper gasket, the positive side welding plate, the lower gasket and the lower pole by using a tooling fixture, and welding and fixing the upper pole and the lower pole by using laser welding to obtain the positive electrode assembly component;

[0066] (2) Fabricating the battery cell: Welding the lower pole of the positive electrode assembly component and the positive electrode plate of the battery cell to obtain the assembled battery cell;

[0067] (3) Inserting the battery cell into the shell: Placing the assembled battery cell into the battery shell, welding the negative electrode welding plate and the negative electrode plate, and finally sealing and welding the positive side welding plate and the battery shell.

[0068] Specifically, in step (1), the thickness of the positive electrode side welding plate is greater than the thickness of the battery case, preferably 8 mm, which is beneficial to the subsequent sealing of the battery case and is not easily deformed.

[0069] Specifically, in step (1), the compression rate of the upper gasket and the lower gasket is 10% to 40%. The upper gasket and the lower gasket are made of elastic and acid-resistant materials to achieve the best sealing effect.

[0070] Specifically, in step (2), a sweeping welding process is used to weld the lower pole column of the positive electrode assembly member and the positive electrode plate of the battery cell. The welding position is on its long side to increase the welding area and improve the large current charge and discharge performance, as Figure 16 shown.

[0071] It should be noted that in this article, the terms "including", "comprising" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0072] In this article, specific examples are used to elaborate on the principle and implementation mode of the present invention. The description of the above examples is only used to help understand the method and its core idea of the present invention.

[0073] The above is only the preferred implementation mode of the present invention. It should be pointed out that due to the limited nature of written expression and the objectively infinite specific structures, for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements, refinements or changes can be made, or the above technical features can be combined in an appropriate manner; these improvements, refinements, changes or combinations, or directly applying the concept and technical solution of the present invention to other occasions without improvement, should all be regarded as the protection scope of the present invention.

Claims

1. A secondary battery, characterized in that: It comprises a positive electrode assembly component (1) and a battery casing (2); The positive electrode side of the battery housing (2) is provided with an opening (21), and the opening (21) is adapted to fit the positive electrode assembly component (1); the non-positive electrode side of the battery housing (2) is sealed; The battery housing (2) is provided with a plurality of recessed portions (22) on the side opposite to the positive electrode, which are used for the negative electrode welding plate (23), and the negative electrode welding plate (23) is connected to the negative electrode plate (3); The positive electrode assembly component (1) comprises an upper pole (11), an upper sealing gasket (12), a positive electrode side welding plate (13), a lower sealing gasket (14) and a lower pole (15), wherein the upper pole (11), the upper sealing gasket (12), the positive electrode side welding plate (13), the lower sealing gasket (14) and the lower pole (15) are arranged in sequence from top to bottom, and the middle of the upper pole (11) is concave to form an inner concave portion (111); The upper sealing gasket (12) is arranged between the upper pole (11) and the positive side welding plate (13), and the positive side welding plate (13) is matched with the opening (21) of the battery shell and is used for sealing the battery shell; the lower sealing gasket (14) is arranged between the positive side welding plate (13) and the lower pole (15), and the upper sealing gasket (12) and the lower sealing gasket (14) cooperate to form an insulating seal to prevent the upper pole (11) and the lower pole (15) from contacting the positive side welding plate (13); the upper sealing gasket (12), the positive side welding plate (13) and the lower sealing gasket (14) are all provided with through holes matched with the inner recess (111); The lower pole (15) is arranged between the lower sealing gasket (14) and the positive electrode plate (4), and the bottom end of the lower pole (15) is connected to the positive electrode plate (4); the inner recess (111) of the upper pole passes through the through holes of the upper sealing gasket (12), the positive electrode side welding plate (13) and the lower sealing gasket (14) in sequence, and the bottom end of the inner recess (111) is connected to the top end of the lower pole (15).

2. A secondary battery according to claim 1, characterized in that: The inner concave portion (111) of the upper pole is fixed to the lower pole (15) by welding, and the bottom end of the lower pole (15) is fixed to the positive plate (4) by welding.

3. A secondary battery according to claim 1, characterized in that: The upper sealing gasket (12) comprises a plane portion (121) and a columnar portion (122); a first groove (123) is provided on the upper surface of the plane portion (121); and a first protrusion (112) adapted to the first groove (123) is provided at a corresponding position on the lower surface of the upper pole (11); A second groove (141) is provided on the lower surface of the lower sealing pad (14), and a second protrusion (151) matching the second groove (141) is provided at a corresponding position on the upper surface of the lower pole (15); The upper surface of the lower sealing pad (14) is provided with a third groove (142), and the third groove (142) is adapted to the bottom end of the cylindrical portion (122); The upper sealing gasket (12) is clamped and fixed between the upper pole (11) and the positive electrode side welding plate (13), and the lower sealing gasket (14) is clamped and fixed between the lower pole (15) and the positive electrode side welding plate (13), forming an insulating seal.

4. A secondary battery according to claim 3, characterized in that: A fourth groove (152) is provided on the upper surface of the lower pole (15), and the fourth groove (152) is adapted to fit the lower sealing gasket (14); A third protrusion (153) is provided in the middle of the upper surface of the lower pole (15), and the third protrusion (153) is embedded in the through hole of the lower sealing gasket (14).

5. A secondary battery according to claim 4, characterized in that: A fourth protrusion (143) is provided on the lower surface of the lower sealing pad (14), and the fourth protrusion (143) is arranged on the outer edge of the lower pole (15).

6. A battery module, characterized in that: The secondary batteries according to any one of claims 1 to 5 are connected in series and / or in parallel.

Images