Battery cell and battery module

Abstract

The utility model provides a battery cell and battery module, the battery cell of the utility model comprises a shell with two open ends and a cover plate used for installing a pole, the opening of each end of the shell is expanded to form an installation part, and the inner cavity of the shell is expanded in the installation part to form an installation groove; and the cover plate is embedded in the mounting groove to seal the shell. According to the battery cell disclosed by the utility model, under the condition that the size of the middle main body is not changed, the two ends of the battery cell can be provided with larger cover plates, and the positive pole or the negative pole with larger size can be arranged on the cover plates, so that the welding area of the positive pole or the negative pole and the busbar is larger and the overflowing cross section is larger when the battery cell is subsequently welded with the busbar; the high-voltage over-current capability of a battery module using the battery cell is improved, and the temperature rise and heating of the battery cell in the fast charging process are reduced, so that the fast charging capability of a battery pack is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a battery core. The utility model also relates to a battery module equipped with the battery core. Background Art

[0002] With the development of technology, blade cells have emerged. Blade cells are increasingly popular due to their high energy density and better size and shape, and are a key direction for major battery energy companies today. The positive and negative poles of blade cells are usually set at both ends of their length. In the battery module, the blade cells are stacked horizontally in sequence and connected in series and parallel through a busbar, with excellent electrical performance.

[0003] However, nowadays people have an increasingly higher demand for fast charging, and blade cells are limited by the size of their two ends in the length direction, as well as the horizontal stacking arrangement of the blade cells when they are used. This results in a limited available size of the positive and negative poles of the blade cells, and a small welding area with the bus bar, resulting in poor high-voltage current capacity and fast charging capability of the battery pack using blade cells. Utility Model Content

[0004] In view of this, the utility model aims to provide a battery cell to improve the high-voltage current-carrying capacity of the battery pack, so as to further enhance the fast-charging capability of the battery pack.

[0005] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0006] A battery cell comprises a shell with two open ends and a cover plate for mounting a pole, wherein the open ends of the shell are expanded to form a mounting portion, and the inner cavity of the shell is expanded in the mounting portion to form a mounting groove;

[0007] The cover plate is embedded in the installation groove and forms a seal for the shell.

[0008] Furthermore, on both sides of the battery core in the width direction, the mounting portion protrudes from the outer surface of the shell in a stepped shape.

[0009] Furthermore, the distance that the mounting portion protrudes from the outer surface of the shell is 0.5 mm to 2 mm.

[0010] Furthermore, the outer side of the cover plate is covered with an insulating film, and the insulating film is provided with a first window for the pole to pass through.

[0011] Furthermore, an explosion-proof valve is installed on the cover plate, and the insulating film is provided with a second window corresponding to the explosion-proof valve.

[0012] Furthermore, a third window is provided on the insulating film, and the third window allows a temperature sensing collection device to pass through to collect the temperature of the cover plate.

[0013] Furthermore, the battery cell includes a pole piece disposed in the shell, and a pole ear connected to an end of the pole piece, and the pole ear is inserted into the mounting groove.

[0014] Furthermore, the length of the mounting portion in the length direction of the shell is 10 mm to 15 mm.

[0015] Compared with the prior art, the utility model has the following advantages:

[0016] With the battery cell described in the utility model keeping the size of the main body in the middle unchanged, larger cover plates can be provided at both ends of the battery cell. By using a larger cover plate, a positive electrode column or a negative electrode column with a larger size can be provided on the cover plate, so that when the battery cell is subsequently welded to the bus bar, the welding area between the positive electrode column or the negative electrode column and the bus bar is larger, and the current flow cross section is also larger, thereby improving the high-voltage current flow capacity of the battery cell, reducing the temperature rise and heat generation during the fast charging process of the battery cell, and thus improving the fast charging capacity of the battery pack; secondly, the use of a larger cover plate can also enable the parts or structures on other cover plates to be adjusted accordingly to obtain better use quality; furthermore, after the battery cell expands during use, the main deformation is concentrated in the middle part, and when the battery cells are stacked and assembled, a gap will be formed between the middle parts of adjacent battery cells, which can absorb the expansion of the battery cell and leave the two ends of the battery cell unaffected.

[0017] The mounting portion is arranged in a stepped shape, which can reduce the difficulty of the stacking process between multiple battery cells, and at the same time form gaps between adjacent battery cells to absorb the expansion volume of the battery cells.

[0018] The protruding height of the mounting portion is determined within a range according to the actual design of the battery cell, ensuring that the battery cells do not affect each other when they expand, while having a smaller cell gap to obtain a higher energy density.

[0019] The insulating film provides electrical insulation to ensure that a short circuit does not occur between the positive and negative electrodes of the battery cell due to external factors, thereby improving the safety of the battery; because the size of the cover plate increases, the size of the insulating film also increases relatively, and the area in which the first window can be opened increases, and accordingly, it can adapt to the size of a larger positive electrode column or a larger negative electrode column.

[0020] The explosion-proof valve is mainly used to prevent the battery cell from exploding, catching fire or other serious consequences due to excessive internal gas in abnormal situations such as overcharging, over-discharging or short circuit. The second window of the insulating film can facilitate the exhaust of the explosion-proof valve.

[0021] The temperature sensing collection device of the battery module collection part can be connected to the cover plate through the third window to collect the temperature.

[0022] When the middle part of the battery cell expands, the expanded volume enters the open space between the two mounting parts. Since both ends of the pole piece are located in the middle of the shell, the deformation caused by the expansion at the mounting part is very small. Based on the above-mentioned setting of the distance of the mounting part protruding from the outer surface of the shell, the battery cell spacing in the battery module using the battery cell in this embodiment can be the same as the battery cell spacing in the battery module using ordinary battery cells, without affecting the overall energy density, while obtaining a larger cover plate size.

[0023] The length of the mounting portion in the length direction of the shell is 10 mm to 15 mm, which can reserve a position for arranging the pole ear and also enable the mounting portion to avoid the pole piece.

[0024] Another object of the present invention is to provide a battery module equipped with a plurality of battery cells as described above.

[0025] Furthermore, an isolation layer is filled between adjacent mounting portions.

[0026] The battery module described in the utility model can make the size of the end cover of the battery cell larger without changing the spacing between the battery cells to adapt to the larger size of the positive electrode column or the negative electrode column, so that after the battery cell and the bus are welded, the welding area between the positive electrode column or the negative electrode column and the bus bar is larger, thereby improving its own high-voltage current carrying capacity, reducing the temperature rise and heat generation during the fast charging process of the battery module, and thus improving the fast charging capability of the battery pack.

[0027] The isolation layer is arranged between the mounting parts of adjacent battery cells. The main expansion parts of the adjacent battery cells have no isolation layer and no force is generated after expansion. Therefore, the position of the battery cell ends in the battery module will not change, making the use of the battery module more stable. Secondly, the size of the isolation layer is reduced, and the material of the isolation layer is reduced accordingly, thereby reducing the production cost of the battery module. Furthermore, a cavity is formed between adjacent battery cells, which can better dissipate heat and improve the heat dissipation performance of the battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0029] Figure 1 This is a schematic exploded view of the positive end of a battery cell according to a first embodiment of the utility model;

[0030] Figure 2 This is a schematic diagram of an exploded view of the negative end of a battery cell according to a first embodiment of the utility model;

[0031] Figure 3 This is an exploded schematic diagram of the battery module structure of the second embodiment of the utility model.

[0032] Description of reference numerals:

[0033] 1. Shell;

[0034] 101, mounting portion; 1011, mounting surface; 102, mounting groove; 103, middle section;

[0035] 2. Cover plate;

[0036] 3. Positive pole;

[0037] 4. Negative pole;

[0038] 5. Insulation film;

[0039] 501, first window; 502, second window; 503, third window;

[0040] 6. Explosion-proof valve;

[0041] 7. Earpiece;

[0042] 8. Isolation layer. DETAILED DESCRIPTION

[0043] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0044] In the description of the present invention, it should be noted that if there are terms such as "upper", "lower", "inner", "outer" and the like indicating orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, if there are terms such as "first" and "second", they are also used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0045] In addition, in the description of the present invention, unless otherwise clearly defined, the terms "installation", "connection", "connection" and "connector" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood in combination with specific circumstances.

[0046] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0047] Embodiment 1

[0048] The present embodiment relates to a battery cell, which optimizes the structure of the battery cell to improve the high-voltage current capacity of the battery module and further enhance the fast charging capability of the battery pack.

[0049] In terms of overall structure, a battery cell in this embodiment includes a shell 1 with open ends and a cover plate 2 for mounting a pole. The open ends of the shell 1 are expanded to form a mounting portion 101, and the inner cavity of the shell 1 is expanded in the mounting portion 101 to form a mounting groove 102.

[0050] The cover plate 2 is embedded in the installation groove 102 and forms a seal for the housing 1 .

[0051] As configured above, with the main body size of the middle part of the battery cell unchanged, a larger cover plate 2 can be set at both ends of the battery cell. By using a larger cover plate 2, a larger pole can be set on the cover plate 2, so that when the battery cell and the bus are subsequently welded, the welding area between the pole and the bus is larger, and the current cross-section is also larger, thereby improving the high-voltage current capacity of the battery cell, reducing the temperature rise and heat generation during the fast charging process of the battery cell, and thus improving the fast charging capacity of the battery pack. Secondly, the use of a larger cover plate 2 can also make corresponding adjustments to the parts or structures on other cover plates 2 to obtain better use quality. Furthermore, after the battery cell expands during use, the main deformation is concentrated in the middle part. When the battery cell is stacked and assembled, a gap will be formed between the middle parts of adjacent battery cells, which can absorb the expansion of the battery cell and leave the two ends of the battery cell unaffected.

[0052] Based on the above overall introduction, refer to Figure 1 and Figure 2 As shown, specifically, this embodiment takes a blade-structured battery cell as an example to introduce the structure and function. The pole is divided into a positive pole 3 and a negative pole 4, and the positive pole 3 and the negative pole 4 are respectively arranged on different cover plates 2. Of course, other battery cells that adopt a long strip shape and arrange the positive pole 3 and the negative pole 4 at both ends in the length direction are also possible. The shell 1 adopts a tubular shape with a rectangular cross-section, and after the two open ends are expanded to form a mounting portion 101, the middle portion with unchanged size is the middle section 103, that is, the two mounting portions 101 are connected by the middle section 103. The two ends of the cavity in the shell 1 are respectively connected to the mounting groove 102, and the two cover plates 2 are connected to the two ends of the shell 1 to close the inside of the shell 1.

[0053] In order to make the installation part 101 easy to install, specifically, on both sides of the width direction of the battery cell, the installation part 101 protrudes from the outer surface of the shell 1 in a stepped shape. The structures of the two installation parts 101 are exactly the same, and the two ends in the length direction of the shell 1 are mirrored. The structure and size of each installation part 101 protruding on both sides in the width direction of the shell 1 are also the same, so that the battery cell is in an "I" shape. After the installation part 101 protrudes from the shell 1, it has a mounting surface 1011 parallel to the outer side wall of the middle section 103 of the shell 1. The mounting surface 1011 is used for connecting and arranging the battery cells, which can reduce the difficulty of the stacking process of the battery cells. The wall thickness of the installation part 101 is the same as the wall thickness of the middle section 103 of the shell 1, and can be made by stamping and other processes.

[0054] Regarding the specific size setting of the mounting portion 101, in this embodiment, the distance that the mounting portion 101 protrudes from the outer surface of the housing 1 is 0.5mm to 2mm, that is, the spacing between the mounting surface 1011 and the side wall of the middle section 103 is 0.5mm to 2mm. As for the selection of the value within the specific range, it needs to be determined according to the design form of the actual battery cell, while ensuring that the battery cells will not affect each other when expanding, and having a smaller battery cell gap to obtain a higher energy density. For example, the volume expansion coefficient of the ternary polymer lithium battery is large, so a larger value setting is required.

[0055] For the protective structure of the cover plate 2, an insulating film 5 is attached to the outer side of the cover plate 2, and a first window 501 is provided on the insulating film 5 for the pole to pass through. The insulating film 5 provides electrical insulation to ensure that the positive and negative poles of the battery cell will not short-circuit due to external factors (such as vibration, friction, etc.), thereby improving the safety of the battery. Because the size of the cover plate 2 increases, the size of the insulating film 5 also increases relatively, and the area in which the first window 501 can be opened increases, and accordingly, the size of the larger positive pole 3 or negative pole 4 can be adapted. In this embodiment, the insulating film 5 is made of plastic and bonded to the cover plate 2. It should be noted that the insulating film 5 can also be made of other insulating materials as long as it can meet the insulation and protection requirements of the battery cell.

[0056] In order to obtain a better connection strength between the cover plate 2 and the shell 1, the cover plate 2 and the shell 1 are welded, and the cover plate 2 after welding is flush with the open end of the mounting portion 101, and the overall structural strength is high, which is conducive to the grouping of battery cells. In order to facilitate the assembly of the battery cells later, the positive pole 3 and the negative pole 4 are pre-connected to the cover plate 2, and the positive pole 3 and the negative pole 4 can be connected in the shell 1 when the cover plate 2 is assembled.

[0057] Based on the explosion-proof performance requirements for the battery cell, an explosion-proof valve 6 is installed on the cover plate 2, and the insulating film 5 is provided with a second window 502 corresponding to the explosion-proof valve 6. The explosion-proof valve 6 is mainly used to prevent the battery cell from causing serious consequences such as explosion and fire due to excessive internal gas under abnormal conditions such as overcharging, over-discharging, and short circuit. It can control the pressure of the gas inside the battery through its own structural changes to keep it within a safe range. In this embodiment, the explosion-proof valve 6 is arranged on the cover plate 2 where the positive pole 3 is located, and an explosion-proof plate is adopted. The shape is oblong and the surface is provided with notches. After the thermal runaway inside the battery cell, the gas will break through the explosion-proof valve 6 from the notch to achieve timely exhaust of the battery cell. Because the size of the cover plate 2 is increased, the size of the explosion-proof valve 6 that can be set can also be increased. The explosion-proof valve 6 with an increased size can have a higher exhaust rate, which improves the exhaust capacity of the battery cell during thermal runaway and makes the use of the battery cell safer.

[0058] Based on the demand for temperature collection of the battery cell, a third window 503 is provided on the insulating film 5, and the third window 503 allows the temperature sensing collection device to pass through to collect the temperature of the cover plate 2. The temperature sensing collection device of the battery module collection part can pass through the third window 503 to connect with the cover plate 2 to collect temperature. As the size of the cover plate 2 increases, the insulating film 5 increases, and the size of the third window 503 can also increase, providing a larger available space for the temperature sensing collection device, which is conducive to the arrangement and assembly of the temperature sensing collection device. In this embodiment, the insulating film 5 with the third window 503 is provided, and is attached to the cover plate 2 provided with the negative pole 4.

[0059] Furthermore, the battery cell includes a pole piece arranged in the shell 1, and a pole ear 7 connected to the end of the pole piece, and the pole ear 7 is inserted into the mounting groove 102 and connected to the corresponding positive pole column 3 or negative pole column 4. When the battery cell is in normal use, the main expansion part is the pole piece, and the corresponding shell 1 structure of this embodiment is the middle section 103. An open space is formed between the outer wall of the middle section 103 and the two mounting parts 101. When the middle section 103 expands, the bulging volume enters the open space. Because both ends of the pole piece are located in the middle section 103, the deformation caused by expansion at the end of the shell 1, that is, the mounting part 101 is very small. Based on the above-mentioned setting of the distance of the mounting part 101 protruding from the outer surface of the shell 1, the battery cell spacing in the battery module using the battery cell in this embodiment can be the same as the battery cell spacing in the battery module using ordinary battery cells, without affecting the overall energy density, while obtaining a larger cover plate 2 size.

[0060] In order to adapt the pole piece and the pole ear 7, the length of the mounting portion 101 in the length direction of the shell 1 is 10mm to 15mm, so that the mounting groove 102 has enough space to accommodate the pole ear 7, which is convenient for welding the pole ear 7 and the pole column. At the same time, the mounting portion 101 can avoid the position of the pole piece so that the pole piece is in the middle section 103.

[0061] The battery cell of the present embodiment optimizes the structure at both ends in the length direction so that larger cover plates 2 can be provided at both ends of the battery cell while the main body size in the middle of the battery cell remains unchanged. A larger positive electrode column 3 or negative electrode column 4 can be provided on the cover plate 2. When the battery cell is subsequently welded to the bus bar, the welding area between the positive electrode column 3 or negative electrode column 4 and the bus bar is larger, thereby improving the high-voltage current carrying capacity of the battery cell and further improving the fast charging capability of the battery pack.

[0062] Embodiment 2

[0063] This embodiment relates to a battery module, which is equipped with a plurality of battery cells in the first embodiment.

[0064] As above, refer to Figure 3 The battery module of this embodiment can make the size of the cell end cover 2 larger without changing the cell spacing to adapt to a larger pole size, so that after the battery cell is welded to the bus bar, the welding area between the positive pole 3 or the negative pole 4 and the bus bar is larger, thereby improving its own high-voltage current capacity, reducing the temperature rise and heat generation of the battery module during fast charging, and thus improving the fast charging capability of the battery pack.

[0065] In order to meet the need for electrical isolation between battery cells, an isolation layer 8 is filled between adjacent mounting portions 101. The isolation layer 8 is used to isolate adjacent battery cells and also plays a role in fixing the positions of adjacent battery cells, making the overall structural strength of the battery module higher. Specifically, the area of ​​the isolation layer 8 is equal to the mounting surface 1011 of the mounting portion 101, and completely covers the mounting surface 1011. Two adjacent battery cells are separated and connected by two isolation layers 8.

[0066] In the traditional way of connecting battery cells, the entire side wall between adjacent battery cells needs to be covered with an isolation layer 8. This results in the isolation layer 8 being squeezed to generate a reaction force after the battery cells expand during use, which may cause the distance between two adjacent battery cells to change, affecting the use of the battery cells in the battery module. The isolation layer 8 of this embodiment is arranged between the mounting parts 101 of adjacent battery cells. The main expansion parts of the adjacent battery cells do not have an isolation layer 8, and no reaction force is generated after expansion. Therefore, the position of the battery cell ends in the battery module will not change, making the use of the battery module more stable. Secondly, the size of the isolation layer 8 is reduced, and the material of the isolation layer 8 required is also reduced accordingly, reducing the production cost of the battery module. Furthermore, the cavity is formed between adjacent battery cells, which can better dissipate heat and improve the heat dissipation performance of the battery module.

[0067] In this embodiment, the isolation layer 8 is made of foam material and is connected to the mounting portion 101 by bonding. Foam material is a material with heat insulation, thermal insulation, shockproof and other properties. It is made of polyester material and has the characteristics of light weight, high strength, moisture resistance, high temperature resistance, etc. While isolating adjacent battery cells, it can also connect, fix and buffer the battery cells. Of course, the isolation layer 8 can also be made of rubber material, but the mass is larger, which is not conducive to the lightweight of the battery module.

[0068] The battery module of this embodiment improves its own high-voltage current carrying capacity by assembling multiple battery cells in the first embodiment, reduces the temperature rise and heat generation during the fast charging process of the battery module, and thus improves the fast charging capability of the battery pack.

[0069] 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 battery cell, comprising a shell with two open ends and a cover plate for mounting a pole, characterized in that: The open ends of the shell are expanded to form mounting portions, and the inner cavity of the shell is expanded in the mounting portions to form mounting grooves; The cover plate is embedded in the installation groove and forms a seal for the shell.

2. The battery cell according to claim 1, characterized in that: On both sides of the battery core in the width direction, the mounting portions protrude from the outer surface of the shell in a stepped shape.

3. The battery cell according to claim 2, characterized in that: The distance that the mounting portion protrudes from the outer surface of the shell is 0.5 mm to 2 mm.

4. The battery cell according to claim 1, characterized in that: The outer side of the cover plate is covered with an insulating film, and the insulating film is provided with a first window for the pole to pass through.

5. The battery cell according to claim 4, characterized in that: An explosion-proof valve is installed on the cover plate, and a second window is provided on the insulating film corresponding to the explosion-proof valve.

6. The battery cell according to claim 4, characterized in that: A third window is provided on the insulating film, and the third window allows a temperature sensing collection device to pass through to collect the temperature of the cover plate.

7. The battery cell according to any one of claims 1 to 6, characterized in that: The battery core includes a pole piece arranged in the shell, and a pole ear connected to the end of the pole piece, and the pole ear is inserted into the installation groove.

8. The battery cell according to claim 7, characterized in that: The length of the mounting portion in the length direction of the housing is 10 mm to 15 mm.

9. A battery module, characterized in that: A plurality of battery cells according to any one of claims 1 to 8 are assembled.

10. The battery module according to claim 9, characterized in that: An isolation layer is filled between adjacent mounting portions.

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