Safety battery

Abstract

The utility model relates to the technical field of soft package batteries, in particular to a safety battery, a heat sealing area is arranged on the periphery of the safety battery, the melting points of a heat sealing layer and a first hot melting layer in the heat sealing area are both less than 140 DEG C, and when the temperature of the battery exceeds 140 DEG C, the heat sealing layer and the first hot melting layer are both melted, so that the packaging strength of the battery is reduced, and the safety of the battery is improved. And gas in the battery rushes out from a weak part of battery packaging, so that the possibility of thermal runaway caused by over-high temperature of the battery is reduced, and the safety performance of the battery is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to soft pack battery technical field, specifically, relate to a safe battery. BACKGROUND

[0002] In recent years, the new energy market competition is increasingly fierce, and the market starts to pursue the single large capacity electric core high power, long cycle and other targets; in order to improve the power performance of the electric core, the voltage of lithium ion battery is higher and higher, and the current industry has developed to 4.53V. However, the chemical system is more unstable under high voltage, the positive potential is higher, and the battery safety risk is greater. When the battery is at a higher temperature, a large amount of gas and heat is easily generated, when the gas and heat in the battery cannot be discharged, the battery will be bulged, and the gas generated will reduce the heat conduction speed of the battery, resulting in thermal runaway of the battery, so the gas in the battery needs to be discharged in time when a large amount of high-temperature gas is generated due to the rise of the battery temperature, so as to improve the safety performance of the battery.

[0003] In the prior art, the gas in the battery is discharged by installing an exhaust valve in the battery, but the installation of the exhaust valve is not suitable for soft pack batteries, the shell of the soft pack battery has no rigid support, and cannot provide a fixed support structure for the exhaust valve like a hard shell battery, the installation of the exhaust valve may damage the sealing of the soft pack battery, resulting in leakage or safety problems, so the exhaust problem of the soft pack battery is difficult to solve.

[0004] Therefore, there is an urgent need to invent a safe battery. UTILITY MODEL CONTENTS

[0005] The utility model aims at: in view of the prior art, and provide a kind of safe battery, can be realized in the discharge of gas in battery in the periphery of battery when battery overheating, improve the safety performance of battery.

[0006] To solve the above technical problems, the following technical solutions are adopted in the present application:

[0007] A safe battery is provided, which includes an aluminum plastic film and an electric core packaged in the aluminum plastic film, the electric core is connected with a tab, the surface of the tab is provided with a tab adhesive, the aluminum plastic film and the tab are sealed by the tab adhesive, one side of the aluminum plastic film close to the electric core is provided with a heat sealing layer, the surface of the tab adhesive close to the aluminum plastic film is provided with a first hot melt layer, the periphery of the safe battery is provided with a heat sealing area, and the melting points of the heat sealing layer and the first hot melt layer in the heat sealing area are less than 140 DEG C.

[0008] Specifically, the melting point of the heat sealing layer is greater than the melting point of the first hot melt layer.

[0009] Specifically, the difference between the melting points of the heat sealing layer and the first hot melt layer is less than 30 DEG C.

[0010] Specifically, the melting point of the heat sealing layer is 110-140 DEG C, and the melting point of the first hot melt layer is 100-140 DEG C.

[0011] Specifically, the tab glue further comprises a skeleton layer, the skeleton layer is arranged on the side of the tab glue away from the aluminum plastic film and close to the tab, and a difference between the melting point of the skeleton layer and the melting point of the heat sealing layer is greater than 30 DEG C.

[0012] Specifically, the tab glue further comprises a second hot melt layer, the first hot melt layer and the second hot melt layer are arranged on two sides of the skeleton layer respectively, wherein the second hot melt layer is arranged on the side close to the tab, and the melting point of the second hot melt layer is 100-140 DEG C.

[0013] Specifically, the material of the heat sealing layer is pp material.

[0014] Specifically, the materials of the first hot melt layer and the second hot melt layer are low-melting-point glue, and the material of the skeleton layer is polypropylene.

[0015] Specifically, the thickness of the skeleton layer is 0.05mm-0.1mm.

[0016] Specifically, the melting point of the skeleton layer is 160-170 DEG C.

[0017] The beneficial effects of the utility model lie in that: the application sets the melting points of the heat sealing layer and the first hot melt layer of the heat sealing area to be less than 140 DEG C, when the temperature of the battery exceeds 140 DEG C, the heat sealing layer and the first hot melt layer will all melt, the packaging strength of the battery is reduced, the gas in the battery rushes out from the weak point of the battery packaging, the possibility of thermal runaway caused by the excessively high temperature of the battery is reduced, and since the periphery of the battery is all set to have a lower melting point, the weak point of the packaging can be quickly formed when the battery is overheated at each position, the gas rushes out from the weak point, and since the melting point is lower, the heat sealing temperature required when the battery is heat sealed can be reduced, and the time required for heat sealing is reduced, the production efficiency of the battery is improved, and the energy consumption required for heat sealing is reduced, thereby reducing the cost. ACCURACY

[0018] The drawings described herein are used to provide further understanding of the utility model, and constitute a part of the utility model, and the illustrative embodiment and the description thereof are used to explain the utility model, and do not constitute improper limitation on the utility model. In the drawings:

[0019] Figure 1 It is the structure schematic view of the safety battery of the utility model;

[0020] Figure 2 It is Figure 1 the sectional view of A.

[0021] Wherein: 1-aluminum-plastic film; 11-heat-sealing layer; 2-battery cell; 3-tab; 4-tab adhesive; 41-first hot melt layer; 42-skeleton layer; 43-second hot melt layer; 5-heat-sealing area. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terminology used in the specification of this application is for the purpose of describing specific embodiments only and is not intended to limit this application.

[0023] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0024] Although this application discloses preferred embodiments as described above, it is not intended to limit the claims. Any person skilled in the art can make several possible changes and modifications without departing from the concept of this application. Therefore, the scope of protection of this application should be determined by the scope defined in the claims of this application.

[0025] Implementation Method 1

[0026] like Figures 1-2 As shown, this application provides a safety battery, including an aluminum-plastic film 1 and a battery cell 2 encapsulated within the aluminum-plastic film 1. The battery cell 2 is connected to a tab 3. A tab adhesive 4 is provided on the surface of the tab 3. The aluminum-plastic film 1 and the tab 3 are sealed by the tab adhesive 4. A heat-sealing layer 11 is provided on the side of the aluminum-plastic film 1 near the battery cell 2. A first hot-melt layer 41 is provided on the surface of the tab adhesive 4 near the aluminum-plastic film 1. A heat-sealing area 5 is provided on the outer periphery of the safety battery. The heat-sealing area 5 is the area that needs to be heat-sealed in the heat-sealing process of the battery. The melting points of the heat-sealing layer 11 and the first hot-melt layer 41 in the heat-sealing area 5 are both less than 140°C.

[0027] The process of common power battery thermal runaway is that first, a single battery in the battery pack causes local severe temperature rise due to mechanical abuse, electrical abuse, thermal abuse and other factors, and the high temperature and fire caused by the single battery accumulating a large amount of heat will cause the thermal runaway of the surrounding single batteries, thereby causing the thermal runaway phenomenon to spread inside the battery pack. The battery thermal runaway can be divided into three stages, including the first stage of resistance increase and battery temperature rise due to thermal inducement, the thermal accumulation stage of battery temperature rise speed increasing due to temperature rise and battery separator decomposition, and the termination stage of thermal runaway due to the melting of the separator and the formation of a serious internal short circuit.

[0028] Therefore, in order to prevent the battery from entering the thermal accumulation stage, the temperature of the battery should not exceed the melting temperature of the separator of the battery. In order to prevent the temperature of the battery from being too high to melt the separator of the battery, the melting point of the heat sealing layer 11 of the peripheral heat sealing area 5 and the first heat melting layer 41 is set to be less than 140℃, which is the temperature at which most separators begin to melt. When the temperature of the battery reaches the melting temperature of the separator, the battery aluminum plastic film 1 seals the battery cell 2 by heating the heat sealing layer 11 of the two aluminum plastic films 1 to fuse the heat sealing layer 11 of the two aluminum plastic films 1 to achieve sealing of the battery. When the temperature of the battery is too high, the heat sealing layer 11 connecting the two aluminum plastic films 1 melts, reducing the sealing strength at the heat sealing layer 11, and the gas in the battery rushes out through the opening formed by the heat sealing layer 11, and the temperature of the battery decreases to prevent the separator from melting and causing the thermal runaway to intensify, thereby improving the safety performance of the battery. The melting point of the heat sealing area 5 is set to be low, so that the temperature rise of the battery at each position of the heat sealing area 5 can form an opening for gas discharge. When the battery is locally overheated, an opening with high sensitivity can be formed to help control the battery in the initial stage of thermal runaway. Moreover, since openings can be formed at each position of the heat sealing area 5 in the battery, the effect of the installation position of the battery on the exhaust of the battery does not need to be considered, the installation of the battery is more flexible, and the melting point is low, so that the temperature required for heat sealing of the battery is lower, the energy consumption is lower, and the efficiency is faster.

[0029] Preferably, the melting point of the heat sealing layer 11 is greater than the melting point of the first heat melting layer 41. In this way, the heat sealing layer 11 and the first heat melting layer 41 can be sequentially melted during heat sealing of the battery. Since the battery is not flat at the tab 3, there may be a position where the tab 3 is not completely sealed. By setting the melting point of the first heat melting layer 41 to be lower, the tab glue 4 can be melted first to fill the gap, which helps the heat sealing layer 11 and the first heat melting layer 41 to be closely attached, thereby improving the sealing performance.

[0030] Preferably, the difference between the melting points of the heat sealing layer 11 and the first hot melt layer 41 is less than 30°C. When the difference between the melting points is too large, the first hot melt layer 41 may melt prematurely during the heat sealing process and flow under the action of heat pressing and form an opening at the tab 3 during continuous heating, while the heat sealing layer 11 fails to melt completely, resulting in uneven melting and sealing, and it is difficult to set a suitable melting temperature for the heat sealing layer 11 and the first hot melt layer 41 together, and the heat sealing temperature between the temperature and the aluminum plastic film 1 is not uniform, so one-time sealing cannot be performed. Therefore, the present application controls the heat sealing layer 11 and the first hot melt layer 41 to help achieve one-time heat sealing and improve heat sealing efficiency.

[0031] Preferably, the melting point of the heat sealing layer 11 is 110-140°C, and the melting point of the first hot melt layer 41 is 100-140°C. Within the above temperature range, the melting points of the first hot melt layer 41 and the heat sealing layer 11 are similar, which can achieve sufficient melting and bonding of the two layers of materials, thereby achieving high sealing efficiency. The similar melting points can complete the heat sealing between the aluminum plastic films 1 and the heat sealing between the aluminum plastic film 1 and the tab adhesive 4 in one heat sealing process, reducing the heat sealing steps and improving the production efficiency of the battery.

[0032] Preferably, the tab adhesive 4 further comprises a skeleton layer 42, which is arranged on the side of the tab adhesive 4 away from the aluminum plastic film 1 and close to the tab 3. The difference between the melting point of the skeleton layer 42 and the melting point of the heat sealing layer 11 is greater than 30°C. By arranging the skeleton layer 42 with a higher melting point, when the first hot melt layer 41 melts, it can prevent over-melting and ensure the packaging thickness, thereby preventing short circuit between the tab 3 and the aluminum plastic film 1.

[0033] Preferably, the tab adhesive 4 further comprises a second hot melt layer 43, and the first hot melt layer 41 and the second hot melt layer 43 are arranged on both sides of the skeleton layer 42, respectively. The second hot melt layer 43 is arranged on the side close to the tab 3. The melting point of the second hot melt layer 43 is 100-140°C. By arranging the second hot melt layer 43, the position where the tab adhesive 4 contacts the tab 3 will also be hot-melted. During the heat sealing process, the aluminum plastic film 1 at the tab 3 will form the shape of the tab 3 and the tab adhesive 4. When the temperature is too high, the tab adhesive 4 will fall off, while the aluminum plastic film 1 will maintain its original shape and form an exhaust space at the tab 3. The exhaust space can smoothly exhaust the gas in the battery, and a stable opening is formed to prevent the battery from closing the opening again after the gas is exhausted, thereby preventing the battery from forming thermal runaway again.

[0034] Specifically, the material of the heat sealing layer 11 is pp material.

[0035] Specifically, the materials of the first hot melt layer 41 and the second hot melt layer 43 are both low-melting-point glue, which is a type of glue that can melt at a relatively low temperature, and the melting point is 100-140°C. The material of the skeleton layer 42 is polypropylene.

[0036] Preferably, the thickness of the skeleton layer 42 is 0.05mm-0.1mm, when the thickness of the skeleton layer 42 is in the range, the shape of the aluminum-plastic film 1 needs to match the shape of the skeleton layer 42 after heat sealing, because the skeleton layer 42 will not melt during heat sealing, the height of the exhaust space formed by the falling of the tab adhesive 4 after melting is at least greater than the thickness of the skeleton layer 42, the smooth exhaust of the battery can be ensured in the above range, and the skeleton layer 42 with a certain thickness can ensure the insulation between the aluminum-plastic film 1 and the tab 3.

[0037] Specifically, the melting point of the skeleton layer 42 is 160-170℃.

[0038] Preparation of a safety battery

[0039] The aluminum-plastic film, the tab adhesive and the tab are heat sealed at 150℃ for 2s to complete the packaging of the battery cell and form a safety battery, wherein the aluminum-plastic film is provided with a pp layer with a melting point of 120℃, the tab adhesive is provided with a low-melting-point adhesive layer with a melting point of 115℃ and a polypropylene layer with a melting point of 165℃.

[0040] Conventional battery

[0041] Unlike the safety battery, the conventional battery is heat sealed at 190℃ for 3s to complete the packaging of the battery cell, and the melting point of the aluminum-plastic film and the tab adhesive is 160℃.

[0042] Thermal abuse test

[0043] Take 9 batteries of the same model and put them into a temperature chamber, and make the temperature chamber rise from the test environment temperature to 132℃±2℃ at a rate of 5℃ / min, and stop heating after keeping this temperature for 30min: after completing the above test steps, observe for 1h at the test environment temperature, and observe whether the temperature of the battery decreases, if the temperature decreases, it is the first thermal abuse test passed, and repeat the above steps to perform the second thermal abuse test, if the temperature decreases, it is the second thermal abuse test passed.

[0044] The thermal abuse test results of the safety battery and the conventional battery are shown in Table 1

[0045] Table 1

[0046]

[0047]

[0048] As can be seen from the above table, the safety battery of the present application has good effect on the passing of thermal abuse, effectively improving the safety performance of the battery.

[0049] The above description shows and describes several preferred embodiments of the present application, but as before, it should be understood that the present application is not limited to the forms disclosed herein, should not be considered as excluding other embodiments, and can be used in various other combinations, modifications and environments, and can be modified within the scope of the present application concept, by the above teaching or related technical or knowledge. The modification and change made by the person skilled in the art without departing from the spirit and scope of the present application shall be within the protection scope of the claims of the present application.

Claims

1. A safety battery, characterized by: The safety battery comprises an aluminum plastic film (1) and an electric core (2) encapsulated in the aluminum plastic film (1), the electric core (2) is connected with a tab (3), the tab (3) is provided with a tab rubber (4) on the surface, the aluminum plastic film (1) and the tab (3) are sealed by the tab rubber (4), the aluminum plastic film (1) is provided with a heat sealing layer (11) on the side close to the electric core (2), the tab rubber (4) is provided with a first hot melt layer (41) on the surface close to the aluminum plastic film (1), the safety battery is provided with a heat sealing area (5) on the periphery, and the melting points of the heat sealing layer (11) and the first hot melt layer (41) in the heat sealing area (5) are less than 140 DEG C.

2. The battery of claim 1, wherein: The melting point of the heat sealing layer (11) is greater than the melting point of the first hot melt layer (41).

3. The battery of claim 2, wherein: The difference between the melting points of the heat sealing layer (11) and the first hot melt layer (41) is less than 30 DEG C.

4. The battery of claim 3, wherein: The melting point of the heat sealing layer (11) is 110-140 DEG C, and the melting point of the first hot melt layer (41) is 100-140 DEG C.

5. The battery of claim 1, wherein: The tab rubber (4) further comprises a skeleton layer (42), the skeleton layer (42) is arranged on the side of the tab rubber (4) away from the aluminum plastic film (1) and close to the tab (3), and the difference between the melting points of the skeleton layer (42) and the heat sealing layer (11) is greater than 30 DEG C.

6. The battery of claim 5, wherein: The tab rubber (4) further comprises a second hot melt layer (43), the first hot melt layer (41) and the second hot melt layer (43) are arranged on the two sides of the skeleton layer (42) respectively, and the second hot melt layer (43) is arranged on the side close to the tab (3), and the melting point of the second hot melt layer (43) is 100-140 DEG C.

7. The battery of claim 1, wherein: The material of the heat sealing layer (11) is pp material.

8. The battery of claim 6, wherein: The materials of the first hot melt layer (41) and the second hot melt layer (43) are low-melting-point glue, and the material of the skeleton layer (42) is polypropylene.

9. The battery of claim 6, wherein: The thickness of the skeleton layer (42) is 0.05mm-0.1mm.

10. The battery of claim 5, wherein: The melting point of the skeleton layer (42) is 160-170 DEG C.

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