Lithium battery structure

Abstract

The utility model discloses a lithium battery structure which comprises a shell and a cover cap, the cover cap comprises a structural plate and a top cover located on one side, far away from the shell, of the structural plate, the edge of the structural plate is turned up towards one side of the top cover to form a second assembling groove, the top cover is embedded and installed in the second assembling groove, and the top cover is arranged in the second assembling groove. The structural plate is installed at one end of the shell. The top cover is embedded into the second assembling groove in the structural plate, so that the relative positions of the top cover and the structural plate are fixed, the floating range of a contact resistor between the top cover and the structural plate is reduced, the performance stability of the battery is improved, and the service life of the lithium battery is prolonged. Besides, the top cover is in contact with the three groove walls of the second assembly groove, so that compared with the prior art that the top cover is in single-face fitting contact with the structural plate, the contact area of the top cover and the structural plate is increased, the contact resistance is reduced, and the battery performance is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, in particular to a lithium battery structure. Background Art

[0002] At present, the mainstream structure of lithium-ion batteries (i.e., lithium batteries) is to limit the structural plate and the top cover by the outer shell. The structural plate and the top cover are generally connected by welding. When the structure is in use, especially when the positive electrode (i.e., the top cover) is fixed, if it encounters high temperature, vibration, impact or long-term use, it may lead to desoldering. After the structural plate and the top cover are desoldered, if the lithium battery is still used in an environment that causes the lithium battery to desolder, especially in an environment where vibration or other conditions cause the lithium battery to move, the top cover will move relative to the structural plate. If the displacement change is relatively large, the contact area between the structural plate and the top cover will change relatively large. This change will cause the contact resistance between the structural plate and the top cover to fluctuate greatly, and ultimately lead to unstable battery performance and even shorten the service life of the lithium battery. Utility Model Content

[0003] In order to overcome at least one of the defects of the prior art described above, the utility model provides a lithium battery structure, which can solve the problem that the contact area between the structural plate and the top cover varies relatively greatly, thereby affecting the battery performance.

[0004] The technical solution adopted by the utility model to solve the problem is:

[0005] A lithium battery structure, comprising:

[0006] shell;

[0007] A cover cap, the cover cap comprising a structural plate and a top cover located on a side of the structural plate away from the housing, an edge of the structural plate being turned up toward a side of the top cover to form a second assembly groove, and the top cover being embedded and installed in the second assembly groove;

[0008] Wherein, the structural plate is installed at one end of the shell.

[0009] By adopting the above solution, the top cover is embedded in the second assembly groove installed on the structural plate, ensuring that the relative position of the top cover and the structural plate is fixed, thereby reducing the floating range of the contact resistance between the top cover and the structural plate, improving the stability of battery performance, and increasing the service life of the lithium battery. In addition, the top cover is in contact with the three sides of the groove wall of the second assembly groove. Compared with the single-sided contact between the top cover and the structural plate in the prior art, the utility model increases the contact area between the top cover and the structural plate, reduces the contact resistance, and improves the battery performance.

[0010] Furthermore, a protective device is provided on the cover cap, and the protective device is arranged in the top cover, or the protective device is arranged in the structural plate, or the protective device is arranged between the top cover and the structural plate.

[0011] Furthermore, a cavity is provided between the top cover and the structural plate, and the protective device is provided in the cavity.

[0012] Further, the middle portion of the top cover is concave in a direction away from the structural plate to form a cavity, or the middle portion of the structural plate is concave in a direction away from the top cover to form a cavity, or the middle portion of the top cover is concave in a direction away from the structural plate and the middle portion of the structural plate is concave in a direction away from the top cover to form a cavity.

[0013] By adopting the above scheme, a protection device is added, which can monitor and / or adjust the temperature of the lithium battery, thereby ensuring that the safety of the battery can be maintained when the battery is not equipped with a current interruption device (CID). In addition, the space for the CID device is eliminated and used to install the protection device, which can match the existing production method and save the cost of opening a new production line. In addition, the technology of the existing production method is more mature and the production efficiency is higher.

[0014] Furthermore, the protection device is one or more combinations of PTC, NTC, resistance wire and temperature switch.

[0015] By adopting the above solution, the designer can select the settings or combined settings of PTC, NTC, resistance wire and temperature switch according to the application environment of the lithium battery, so that the lithium battery can be used normally in different application scenarios and can ensure the lithium battery under extreme conditions.

[0016] Furthermore, a first assembly groove is provided at one end of the shell, and a sealing member is provided between the first assembly groove and the structural plate.

[0017] By adopting the above solution, the provision of the first assembly groove facilitates the installation of the structural plate and the top cover, and the sealing member is provided between the first assembly groove and the structural plate to improve the sealing performance there.

[0018] Furthermore, the sealing material is one of PP, PFA and PPS.

[0019] By adopting the above solution, since in the prior art, the seal will hydrolyze when exposed to a high temperature environment (above 60°C) for a long time, thereby causing the battery to be damaged, the use of PP, PFA or PPS materials can expand the operating temperature of lithium batteries from the existing -20°C to 60°C to a wide temperature range of -40°C to 85°C, thereby expanding the application market.

[0020] Furthermore, the housing is provided with a pressure relief valve.

[0021] By adopting the above solution, when the lithium battery is under extreme conditions, the pressure in the casing can be released through the pressure relief valve to prevent explosion and fire.

[0022] Furthermore, the pressure relief valve includes one or more combinations of a point pressure relief valve, a linear pressure relief valve and a surface pressure relief valve.

[0023] By adopting the above solution, more types of pressure relief valves are provided so as to facilitate free selection in different application environments.

[0024] Furthermore, the shape of the linear pressure relief valve is one or more combinations of a straight line, a broken line and a curve, and the shape of the surface pressure relief valve is a graphic surface surrounded by straight lines and / or curves.

[0025] By adopting the above solution, more types of linear pressure relief valves and surface pressure relief valves are provided, which is convenient for subsequent selection according to different application scenarios of lithium batteries.

[0026] In summary, the lithium battery structure provided by the utility model has the following technical effects:

[0027] 1. The top cover is embedded in the second assembly groove installed on the structural plate to ensure that the relative position of the top cover and the structural plate is fixed, thereby reducing the floating range of the contact resistance between the top cover and the structural plate, improving the stability of battery performance, and increasing the service life of the lithium battery;

[0028] 2. The top cover is in contact with the three groove walls of the second assembly groove. Compared with the single-sided contact between the top cover and the structural plate in the prior art, the utility model increases the contact area between the top cover and the structural plate, reduces the contact resistance, and improves the battery performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the cross-sectional structure of the utility model;

[0030] Figure 2 It is a cross-sectional view of the exploded structure of the utility model;

[0031] Figure 3 It is a schematic diagram of a point-type pressure relief valve of the utility model;

[0032] Figure 4 This is a schematic diagram of a linear pressure relief valve of the utility model;

[0033] Figure 5 It is a schematic diagram of another linear pressure relief valve of the utility model;

[0034] Figure 6It is a schematic diagram of the arc-shaped pressure relief valve of the utility model.

[0035] Among them, the meanings of the figure numbers are as follows: 1. outer shell; 11. pressure relief valve; 12. first assembly groove; 13. rolling groove; 2. cover cap; 21. structural plate; 211. second assembly groove; 22. top cover; 23. sealing; 3. protective device; 4. top gasket; 5. winding core. DETAILED DESCRIPTION

[0036] For better understanding and implementation, the technical solutions in the embodiments of the present invention will be clearly and completely described and discussed below in conjunction with the accompanying drawings of the present invention. Obviously, what is described here is only a part of the examples of the present invention, not all the examples. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0037] In order to facilitate the understanding of the embodiments of the present utility model, the following will be further explained by taking specific embodiments as examples in conjunction with the drawings, and each embodiment does not constitute a limitation on the embodiments of the present utility model.

[0038] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0040] See also Figure 1 and Figure 2As shown, it includes a shell 1 and a cap 2. The cap 2 includes a structural plate 21 and a top cover 22 located on the side of the structural plate 21 away from the shell 1. The edge of the structural plate 21 is turned up toward the side of the top cover 22 to form a second assembly groove 211. The top cover 22 is embedded and installed in the second assembly groove 211, that is, the edge of the top cover 22 is inserted into the second assembly groove 211 of the structural plate 21. In the above structure, even if the top cover 22 and the structural plate 21 are not welded, the structural plate 21 and the top cover 22 can maintain good contact. At the same time, the top cover 22 is embedded and installed in the second assembly groove 211. The inner wall of the top cover 22 and the second assembly groove 211 are both in a fitted state, which increases the contact area between the top cover 22 and the structural plate 21, greatly reduces the contact impedance between the top cover 22 and the structural plate 21, and thus improves the performance of the lithium battery.

[0041] Furthermore, the seal 23 may be provided with a fold corresponding to the portion of the second assembly groove 211 extending to the first assembly groove 12, which can further improve the sealing performance of the structural plate 21 and the first assembly groove 12.

[0042] In some embodiments, the cap 2 is further provided with a protective device 3, and the protective device 3 can be arranged in various positions, wherein the protective device 3 can be buried in the top cover 22, buried in the structural plate 21, or arranged between the top cover 22 and the structural plate 21. The specific arrangement position of the protective device 3 can be freely selected according to different lithium batteries. In this embodiment, in order to facilitate the production of lithium batteries, the protective device 3 is arranged between the top cover 22 and the structural plate 21.

[0043] Specifically, the protection device 3 can monitor and / or adjust the temperature of the lithium battery. Regarding the protection device 3 monitoring the temperature of the lithium battery to improve the safety of the lithium battery in a high temperature environment, the specific monitoring conditions are as follows (the following briefly introduces the conditions in which this function can be realized, and other implementation methods that can achieve this technical effect will not be repeated here): When the temperature is at a preset dangerous threshold, a signal is sent to the control circuit to disconnect the circuit or reduce the frequency of the lithium battery participating in charging / discharging, so as to improve the safety of the lithium battery in a high temperature environment. Regarding the protection device 3 regulating the temperature of the lithium battery to improve the safety of the lithium battery in a high temperature environment, a resistance wire can be set. The resistance wire will generate a certain amount of heat when working, which can help adjust the temperature of the battery and ensure the safety and stable operation of the battery. In addition, a pressure relief valve 11 is set in the outer shell 1. Under extreme conditions, the pressure in the outer shell 1 is released through the pressure relief valve 11 to prevent explosions and fires.

[0044] In order to facilitate the installation of the protection device 3 between the top cover 22 and the structural plate 21, a cavity is provided between the top cover 22 and the structural plate 21, and the protection device 3 is provided in the cavity. In the prior art, the top cover 22 is generally used to set a CID device. In the present utility model, the space used to install the CID device is eliminated and used to install the protection device 3, so that the existing production method can be matched, the cost of opening a new production line can be saved, and the technology of the existing production method is more mature and the production efficiency is higher.

[0045] In addition, there are three main ways to form the cavity: first, the middle of the top cover 22 is concave in the direction away from the structural plate 21 to form the cavity; second, the middle of the structural plate 21 is concave in the direction away from the top cover 22 to form the cavity; third, the middle of the top cover 22 is concave in the direction away from the structural plate 21 and the middle of the structural plate 21 is concave in the direction away from the top cover 22 to form the cavity together. The specific processing method of the cavity can be selected according to other structures of the lithium battery, and it can match the existing lithium battery processing line as much as possible, so as to save the cost of opening a new production line.

[0046] In some embodiments, the middle of the top cover 22 is concave in the direction away from the structural plate 21 to form a cavity, and the protective device 3 is arranged in the cavity. In the prior art, the top cover 22 is generally used to set the CID device. In the present utility model, the space used to install the CID device is eliminated and used to install the protective device 3, so that the existing production method can be matched, and the cost of opening a new production line can be saved. The technology of the existing production method is more mature and the production efficiency is higher. In addition, in the prior art, since the installation of the CID device will cause the lithium battery to fail when it is in a high temperature state for a long time, the elimination of the CID device can achieve the purpose of long-term operation of the lithium battery at high temperature, thereby broadening the application field of the lithium battery.

[0047] In some embodiments, the protection device 3 is a combination of one or more of PTC, NTC, resistance wire and temperature switch. Among them, the PTC can be set to limit the further increase of the current through its own temperature sensing characteristics when the temperature of the lithium battery is too high, thereby preventing the occurrence of safety accidents such as overheating and explosion of the lithium battery. The NTC can be set to limit the further reduction of the current through its own temperature sensing characteristics when the temperature of the lithium battery is too low, thereby preventing the influence of excessive discharge and charging of the lithium battery on the performance and service life of the lithium battery. The resistance wire can generate a certain amount of heat during the charging and discharging process of the lithium battery, which helps to adjust the temperature of the battery and ensure the safety and stable operation of the battery. When the temperature of the lithium battery reaches the preset warning value, the temperature switch will automatically close or adjust the circuit to prevent the battery from overheating or overcooling, thereby protecting the safety and stable operation of the battery. The temperature switch can also control the charge and discharge state of the battery to prevent the battery from overheating when charging and discharging with a large current, thereby ensuring the service life and safety of the battery.

[0048] In this embodiment, in order to conveniently ensure the airtightness between the structural plate 21 and the housing 1, a first assembly groove 12 is provided at one end of the housing 1. A part of the second assembly groove 211 of the structural plate 21 is inserted into the first assembly groove 12 for installation. Correspondingly, a sealing member 23 is arranged between the first assembly groove 12 and the structural plate 21. The sealing member 23 partially seals and wraps the second assembly groove 211 of the structural plate 21 to ensure the airtightness of the gap between the part of the second assembly groove 211 of the structural plate 21 and the first assembly groove 12. In addition, an alternative implementation is: the cross-section of the sealing member 23 is in a "C" shape, so as to increase the path that gas needs to pass through when escaping, and further increase the airtightness between the structural plate 21 and the sealing member 23, and between the sealing member 23 and the first assembly groove 12.

[0049] Since some common materials of the sealing member 23 in the prior art are extremely prone to hydrolysis when in a high-temperature and high-humidity environment for a long time, in order to further expand the applicable temperature range of the lithium battery and ensure that the sealing member 23 will not hydrolyze in a long-term high-temperature environment, the material of the sealing member 23 of the present utility model is one of PP, PFA, and PPS. The materials of PP, PFA, or PPS can broaden the operating temperature of the lithium battery from the existing -20°C to 60°C to a wide temperature range of -40°C to 85°C, expanding the application market. It has been verified that the materials of PP, PFA, or PPS can not hydrolyze in an environment of 85°C and 85% RH (RH: Relative Humidity).

[0050] It should be noted that the sealing member 23 made of a material that can not hydrolyze in an environment of 85°C and 85% RH (RH: Relative Humidity) can be used on the basis of the lithium battery structure without a CID device to broaden the application environment range of the lithium battery, and can also be used on the basis of the lithium battery structure with a CID device, so that the lithium battery can cope with some extreme high-temperature situations and improve the safety performance of the lithium battery.

[0051] In order to improve the safety performance of the lithium battery and also provide safety protection on the basis of the structure of the lithium battery without a CID device, a pressure relief valve 11 is provided on the housing 1.

[0052] Specifically, the pressure relief valve 11 can be a mechanical valve or an electronic valve controlled by a spring. When the pressure reaches the threshold value, the pressure relief valve 11 opens to release air and relieve pressure. It is also possible to etch the housing 1 so that the thickness of the etched part of the housing 1 is less than the thickness of the unetched part of the housing 1. When the pressure inside the housing 1 increases to break the etched part of the housing 1, pressure relief is completed, avoiding explosion and fire.

[0053] In this embodiment, the pressure relief valve 11 is made by etching to thin the thickness of part of the shell 1. Since the thickness of the pressure relief valve 11 formed after etching the shell 1 is less than the thickness of other parts of the shell 1, when the internal air pressure of the lithium battery exceeds the bearing limit of the pressure relief valve 11, the pressure relief valve 11 will first break to release the air pressure inside the lithium battery, thereby reducing the possibility of fire or explosion. Among them, the pressure relief valve 11 can be divided into a point pressure relief valve, a linear pressure relief valve and a surface pressure relief valve according to the style of its pressure relief port. The designer can set one or more combinations of point pressure relief valves, linear pressure relief valves and surface pressure relief valves on the shell 1 as needed.

[0054] The shape of the linear pressure relief valve is one or more combinations of straight line, broken line and curved line. The designer can select the best single style (i.e. straight line, broken line and curved line) or multiple styles (i.e. combination of straight line, broken line and curved line) according to the specific application environment of the lithium battery, such as straight line pressure relief valve, arc pressure relief valve, etc. The shape of the pressure relief port of the surface pressure relief valve is a graphic surface surrounded by straight lines and / or curves, that is, the above-mentioned graphic surface is etched and thinned as a whole to form a groove surface, such as a rectangular surface, an elliptical surface, a circular surface, etc., to meet the needs of different application scenarios.

[0055] Specifically, when using a point-type pressure relief valve, refer to Figure 3 As shown, the point-type pressure relief valves are arranged at equal intervals at the bottom of the housing 1. When a linear pressure relief valve is used, refer to Figure 4-Figure 6 As shown. Figure 4 and Figure 5 It is a linear pressure relief valve. Figure 4 The four straight-line pressure relief valves are arranged in a rectangular shape at the bottom of the housing 1 . Figure 5 The four straight-line pressure relief valves are arranged in a cross shape at the bottom of the housing 1 . Figure 6 The middle one is a curved linear pressure relief valve, and two curved linear pressure relief valves are arranged in a concentric circle pattern at the bottom of the housing 1. Of course, a broken line linear pressure relief valve can also be arranged.

[0056] In addition, in this embodiment, the pressure relief valve 11 is disposed at one end of the housing 1 away from the first assembly groove 12. Of course, it can also be disposed at other positions of the housing 1 according to actual needs. In addition, the user can select the number of pressure relief valves 11 according to the specific application environment requirements. When the application environment requires higher safety and more sensitive release of air pressure, multiple pressure relief valves 11 can be disposed.

[0057] In some embodiments, the outer shell 1 is provided with a rolling groove 13 at one end where the first assembly groove 12 is provided. The rolling groove 13 is a groove that converges along the circumference of the outer shell 1 toward the central axis of the lithium battery. The rolling groove 13 can keep the inner winding core 5 of the lithium battery fixed, which helps to improve the structural strength and stability of the battery. Furthermore, the distance between the rolling groove 13 and the cap 2 is controlled at a position of 1-5mm, which is the upper surface position of the top gasket 4 in common lithium batteries. The distance between the rolling groove 13 and the cap 2 is controlled at a position of 1-5mm, which just offsets the upper surface of the top gasket 4, thereby limiting the displacement of the top gasket 4 over a large distance, thereby limiting the displacement of the inner winding core 5 of the lithium battery over a large distance, so as to improve the structural strength and stability of the battery.

[0058] It should be noted that, in order to facilitate technical understanding, cylindrical lithium batteries are used for display in the drawings of the specification, but the structure of the utility model can be applied to lithium batteries of common shapes other than cylindrical, and is not limited here.

[0059] The technical means disclosed in the solution of the utility model are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical solutions composed of any combination of the above technical features. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the utility model, and these improvements and modifications are also regarded as the protection scope of the utility model.

Claims

1. A lithium battery structure, characterized in that: include: shell; A cover cap, the cover cap comprising a structural plate and a top cover located on a side of the structural plate away from the housing, an edge of the structural plate being turned up toward a side of the top cover to form a second assembly groove, and the top cover being embedded and installed in the second assembly groove; Wherein, the structural plate is installed at one end of the outer shell, and a protective device is also provided on the cover cap. The protective device is arranged in the top cover, or the protective device is arranged in the structural plate, or the protective device is arranged between the top cover and the structural plate.

2. A lithium battery structure according to claim 1, characterized in that: A cavity is provided between the top cover and the structural plate, and the protection device is arranged in the cavity.

3. A lithium battery structure according to claim 2, characterized in that: The middle portion of the top cover is concave in a direction away from the structural plate to form a cavity, or the middle portion of the structural plate is concave in a direction away from the top cover to form a cavity, or the middle portion of the top cover is concave in a direction away from the structural plate and the middle portion of the structural plate is concave in a direction away from the top cover together to form a cavity.

4. A lithium battery structure according to claim 1, characterized in that: The protection device is one or more combinations of PTC, NTC, resistance wire and temperature switch.

5. A lithium battery structure according to any one of claims 1 to 4, characterized in that: A first assembly groove is provided at one end of the shell, and a sealing member is provided between the first assembly groove and the structural plate.

6. A lithium battery structure according to claim 5, characterized in that: The sealing member is made of one of PP, PFA and PPS.

7. A lithium battery structure according to claim 1, characterized in that: The housing is provided with a pressure relief valve.

8. A lithium battery structure according to claim 7, characterized in that: The pressure relief valve includes one or more combinations of a point pressure relief valve, a linear pressure relief valve and a surface pressure relief valve.

9. A lithium battery structure according to claim 8, characterized in that: The shape of the linear pressure relief valve is one or more combinations of a straight line, a broken line and a curve, and the shape of the surface pressure relief valve is a graphic surface surrounded by straight lines and / or curves.

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