Battery tab structure integrated with overvoltage protection, battery and preparation method

Abstract

The invention relates to the technical field of batteries, in particular to a battery tab structure integrated with overvoltage protection, a battery and a preparation method, and the battery tab structure is characterized in that an overcharge protection circuit is lapped between a positive tab and a negative tab and comprises a voltage stabilizing diode and at least one conduction unit; the breakdown voltage of the voltage stabilizing diode is determined according to an overvoltage protection value of the battery, and a control signal is input to the conduction unit during reverse breakdown, so that the conduction unit constructs a shunt channel from the positive pole lug to the negative pole lug. Aiming at the problem that an overcharge protection circuit in the prior art is difficult to be accurate to a single battery cell or is large in scale, whether the positive voltage reaches an overvoltage protection limit value is detected through a reversely connected voltage stabilizing diode, and a shunt channel from a positive electrode to a negative electrode is formed for discharging, so that overvoltage detection and automatic protection functions are realized, and the reliability of the overcharge protection circuit is improved. And the device can be directly integrated on a single battery monomer without externally connecting a sensing circuit and a control circuit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery tab structure integrated with overvoltage protection, a battery and a preparation method. BACKGROUND

[0002] As the core of contemporary energy storage technology, lithium ion batteries have been widely used in consumer electronics, new energy vehicles and large-scale energy storage systems due to their high energy density, long cycle life and low self-discharge rate. Overcharging safety has always been a key challenge to the development of the industry. Overcharging can cause irreversible damage such as electrolyte decomposition, separator melting, and positive electrode material oxygen evolution, and thus cause catastrophic accidents such as fire and explosion. With the popularization of new energy vehicles, the charging speed of lithium ion batteries is becoming higher and higher, and the risk of overcharging is also increasing.

[0003] In the prior art, there are technical solutions for designing overcharge protection circuits for batteries.

[0004] For example, the patent document CN201910482433.8 discloses a battery overcharge protection circuit, which comprises a charging circuit, a voltage dividing circuit, and a control circuit. The first end of the charging circuit is connected to the positive electrode of a charging power supply, the second end of the charging circuit is connected to the positive electrode of a battery, and the charging circuit is used to input the current provided by the charging power supply to the battery for charging. One end of the voltage dividing circuit is connected to the positive electrode of the battery, and the voltage dividing circuit is used to obtain a first voltage value of the battery by dividing the voltage of the battery. The control circuit comprises a reference source for providing a reference voltage value. One end of the control circuit is connected to the other end of the voltage dividing circuit, and the other end of the control circuit is connected to the third end of the charging circuit. The battery overcharge protection circuit uses a hardware solution to detect the voltage of the battery and realizes battery overcharge protection, which is safe and reliable.

[0005] For example, the patent document CN201611241325.4 discloses a battery overcharge protection system, which comprises a battery box, a plurality of battery management units, a battery control unit, a first switch, and a charging pile. The battery box comprises a plurality of battery packs connected in series. Each battery management unit is used to output the voltage of the single battery in the corresponding battery pack collected by the battery management unit to the battery control unit. The battery control unit is used to select the highest voltage of the single battery and calculate the total voltage of the battery box, and compare the highest voltage of the single battery with a first reference value and a second reference value, and compare the total voltage of the battery box with a third reference value and a fourth reference value. The battery control unit is also used to control the charging pile to stop charging the battery box when the highest voltage of the single battery is greater than the first reference value and less than the second reference value, or the total voltage of the battery box is greater than the third reference value and less than the fourth reference value, and control the first switch to be turned off after a delay. The above-mentioned battery overcharge protection system can prevent battery overcharging.

[0006] However, in the actual implementation process, the inventors found that the technical solutions of this kind are usually to set corresponding detection and protection circuits on the charger and the battery management system to realize the overcharge protection of the battery. However, in the application process of the lithium ion battery, a plurality of batteries are often connected in series to form a module and are installed in a battery pack. In this scenario, if the overcharge protection of the lithium ion battery is required, there will be a problem of serious consistency within the module, or a problem of excessive scale of the detection and control circuit. SUMMARY

[0007] In view of the above problems existing in the prior art, the present application provides a battery tab structure integrated with overvoltage protection, and also provides a battery applying the battery tab structure and a preparation method for manufacturing the battery.

[0008] The specific technical solutions are as follows: a battery tab structure integrated with overvoltage protection, comprising a positive tab and a negative tab, wherein an overcharge protection circuit is overlapped between the positive tab and the negative tab; the overcharge protection circuit comprises a zener diode and at least one conduction unit; the cathode of the zener diode is connected to the positive tab, the anode of the zener diode is connected to the control end of the conduction unit and is in conduction with the negative tab; the input end of the conduction unit is connected to the positive tab, and the output end of the conduction unit is connected to the negative tab; the breakdown voltage of the zener diode is determined according to the overvoltage protection value of the battery, and when the zener diode is reversely broken down, a control signal is input to the conduction unit, so that the conduction unit builds a shunt path from the positive tab to the negative tab.

[0009] On the other hand, the conduction unit comprises: a current-limiting resistor, a first end of the current-limiting resistor being connected to the input end of the conduction unit; a triode, a collector of the triode being connected to a second end of the current-limiting resistor, an emitter of the triode being connected to the output end of the conduction unit; and a base of the triode being connected to the control end of the conduction unit.

[0010] On the other hand, the overcharge protection circuit is arranged on a substrate; the substrate is rectangular, and two ends thereof are respectively welded to the positive tab and the negative tab by metal strips to form electrical connection.

[0011] In another aspect, the metal strip includes a first metal strip and a second metal strip having different materials; the first metal strip is welded and fixed with the positive electrode tab, and the first metal strip has the same material as the positive electrode tab; the second metal strip is welded and fixed with the negative electrode tab, and the second metal strip is one of copper, nickel, aluminum, and copper-plated nickel, and preferably the second metal strip has the same material as the negative electrode tab A2; in another aspect, the substrate is arranged on the side of the positive electrode tab and the negative electrode tab close to the battery cell; the positive electrode tab and the negative electrode tab are respectively provided with a tab adhesive on the other side away from the battery cell; and the tab adhesive is arranged on the outer side of the substrate.

[0012] In another aspect, the substrate is made of epoxy glass cloth material; a printed circuit is formed on the substrate by silver conductive adhesive or copper block; and the voltage stabilizing diode and the devices of the conduction unit are connected to the printed circuit by soldering.

[0013] In another aspect, the substrate is further provided with heat-conducting silica gel as an inner layer encapsulation; the heat-conducting silica gel covers the upper and lower surfaces of the substrate; and the outer side of the heat-conducting silica gel is further provided with an aluminum plate encapsulation.

[0014] In another aspect, the tab adhesive is arranged on the inner side of the battery shell.

[0015] A battery includes the above-mentioned battery tab structure.

[0016] A preparation method for manufacturing a battery including the above-mentioned battery tab structure; the preparation method includes: step S1, welding devices on a substrate to obtain an overcharge protection circuit and manufacture an encapsulation circuit; step S2, welding the encapsulation circuit with a positive electrode tab and a negative electrode tab respectively to obtain the battery tab structure; and step S3, manufacturing a battery cell structure and welding the battery cell structure with the battery tab structure, and then performing shell packaging, liquid injection, and formation to obtain the battery.

[0017] The above technical solution has the following advantages or beneficial effects: In view of the problem that the overcharge protection circuit in the prior art is difficult to be accurately applied to a single battery cell or a large scale, in the present solution, the overcharge protection circuit is integrated in the battery tab structure, the overvoltage protection limit value is detected by the reverse-connection voltage stabilizing diode, and the conduction unit is controlled to form a shunt channel from the positive electrode to the negative electrode for discharging, thereby realizing overvoltage detection and automatic protection functions for a single battery cell. The battery tab structure can be directly integrated on a single battery cell and does not need to be externally connected to a sensing and control circuit, can be applied to a battery pack, and does not need to be additionally provided with a large-scale overcharge protection circuit. BRIEF DESCRIPTION OF DRAWINGS

[0018] The embodiments of the present application will be described in more detail with reference to the drawings. However, the attached drawings are only used for illustration and explanation, and do not constitute a limitation on the scope of the present application.

[0019] Figure 1 It is a schematic diagram of the embodiment of the present application; Figure 2 It is a schematic diagram of the conduction circuit of the embodiment of the present application; Figure 3 It is a schematic diagram of the circuit principle of the embodiment of the present application; Figure 4 It is a schematic diagram of the circuit principle of another embodiment of the present application; Figure 5 It is a schematic diagram of the battery tab structure integrated with overvoltage protection in the embodiment of the present application; Figure 6 It is a schematic diagram of the method in the embodiment of the present application; Figure 7 It is a schematic diagram of the battery cell. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0021] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0022] The present application will be further described below in combination with the drawings and specific embodiments, but is not limited by the present application.

[0023] The present application includes: a battery tab structure integrated with overvoltage protection, as shown in Figure 1 including a positive tab A1 and a negative tab A2, and an overcharge protection circuit is overlapped between the positive tab A1 and the negative tab A2; the overcharge protection circuit includes a zener diode 1 and at least one conduction unit 2; the cathode of the zener diode 1 is connected to the positive tab A1, the anode of the zener diode 1 is connected to the control end of the conduction unit 2, and is in conduction with the negative tab A2; the input end of the conduction unit 2 is connected to the positive tab A1, and the output end of the conduction unit 2 is connected to the negative tab A2; the breakdown voltage of the zener diode 1 is determined according to the overvoltage protection value of the battery, and when the zener diode 1 is reversely broken down, a control signal is input to the conduction unit 2, so that the conduction unit 2 builds a shunt path from the positive tab A1 to the negative tab A2.

[0024] Specifically, in view of the problem that the overcharge protection circuit in the prior art is difficult to be accurate to a single battery cell or large in size, in the present scheme, an overcharge protection circuit is integrated in a battery tab structure, whether the positive electrode voltage reaches the overvoltage protection limit value is detected through the reverse connection of a voltage stabilizing diode 1, and a conduction unit 2 is controlled to form a discharge channel from the positive electrode to the negative electrode to shunt the discharge, part of the current will directly return to the charging bus without flowing into the battery, thereby realizing overvoltage detection and automatic protection functions for the single battery cell, the battery tab structure can be directly integrated on a single battery cell and does not need to be externally connected to a sensing and control circuit, and can be applied to a battery pack without the need for additional large-scale overcharge protection circuits.

[0025] Specifically, as shown in Figure 2 When the positive electrode tab A1 and the negative electrode tab A2 are connected to a load A4 and normally work, a corresponding loop will be formed on the line, at this time, since the voltage stabilizing diode 1 is reversely connected, and the voltage of the battery continuously decreases during use, the voltage will always be lower than the reverse breakdown voltage of the voltage stabilizing diode 1. The charging and discharging, and the current direction during overcharge protection are shown in the figure.

[0026] When the battery needs to be charged, the positive electrode tab A1 and the negative electrode tab A2 are connected to a charging power supply A3 and charged, and the voltage of the battery will continuously increase, for example, from 3.2V to 4.2V, assuming that the full voltage of the battery is calibrated as 4.2V and the overcharge protection voltage is 4.4V, during this process, the overcharge protection will not be triggered.

[0027] When the battery itself is overcharged due to consistency problems or charging circuit failure problems, the voltage will continuously increase to 4.4V, at this time, the voltage stabilizing diode 1 is reversely broken down, a control signal is formed to the conduction unit 2, the conduction unit 2 is turned on to form a pressure relief channel from the positive electrode tab A1 to the negative electrode tab A2, and the reversely broken down voltage stabilizing diode 1 will provide a bypass channel, thereby shunting the charging current, so that part of the charging current directly returns to the charging bus through the negative electrode tab A2 without charging the battery.

[0028] At this time, if the overcharge current is not greater than the shunt current on the pressure relief channel and the bypass channel, the battery voltage will not continue to increase; if the overcharge current is greater than the shunt current, the battery voltage will increase at a slower speed, and the line current will also continue to increase, which can greatly reduce the overcharge speed and delay the time of battery thermal runaway, thereby realizing overcharge protection.

[0029] It can be seen from the analysis of the above structure that the above structure is realized only by relying on the overcharge protection circuit lapped on the tab, and does not need to be provided with more complex detection and control circuits. When applied to a battery module and a battery pack, no additional circuit size is needed.

[0030] At the same time, the structure is directly integrated in the tab, which can shorten the protection path by 90%, and the response speed is less than 100 μs without the need for external control circuit. The structure can be built-in in the battery or added at the root of the tab / pole, which has the same effect.

[0031] As an optional embodiment, the conducting unit 2 can be adjusted to various devices such as a switching chip, a MOSFET, an IGBT device, a BJT device, etc. according to needs.

[0032] In one embodiment, as shown in Figure 3 the conducting unit 2 includes: a current-limiting resistor R1, a first end of the current-limiting resistor R1 is connected to the input end of the conducting unit 2; a triode Q1, a collector of the triode Q1 is connected to a second end of the current-limiting resistor R1, an emitter of the triode Q1 is connected to the output end of the conducting unit 2; and a base of the triode Q1 is connected to the control end of the conducting unit 2.

[0033] Specifically, in order to achieve better protection effect, in the embodiment, the triode Q1 is used to achieve better current-limiting conducting effect.

[0034] Specifically, when the battery is accidentally overcharged to cause the voltage to exceed the set threshold value (such as 4.7 V±0.3 V), the first stable voltage diode 1 is reversely broken down to form a bypass channel, and the charging current is instantaneously shunted, so that the charging current directly flows back to the charging bus from the negative tab A2, and the battery is not charged. When the overcharge current is not greater than the shunt current, the battery voltage no longer rises, and overcharge protection is achieved.

[0035] However, since the dynamic resistance of the stable voltage diode 1 is large and the rated power is small, when the overcharge current is still greater than the shunt current, the battery voltage will still slowly rise, and only the stable voltage diode 1 cannot limit the overcharge.

[0036] In view of this problem, the triode Q1 is introduced as the conducting unit 2 to achieve good carrying capacity for large overcharge current.

[0037] When the stable voltage diode 1 is turned on, a current is generated at the base of the input triode Q1, at this time, the triode Q1 collector and emitter are turned on, and the instantaneous large current is discharged. This is because the triode has strong current-carrying capacity, and the triode Q1 front-end series current-limiting resistor R1 is used to limit the current to prevent exceeding the triode current limit value and causing overheating or failure.

[0038] If the total shunt current exceeds the charging current, the battery voltage will also no longer rise, and overcharge protection is achieved. If the overcharge current still exceeds the shunt current, the battery voltage will rise slowly, and at the same time, the line current will also continue to increase, which can greatly reduce the overcharge speed and delay the time of battery thermal runaway.

[0039] The above characteristics can be used to achieve better shunt effect.

[0040] In addition, as Figure 4 shown, in the process of setting the conduction unit 2, a plurality of parallel conduction units 2 can also be set to be respectively lapped on the positive electrode tab A1 and the negative electrode tab A2, thereby improving the carrying capacity of the overcharge current.

[0041] In the process of setting the conduction unit 2, the control end of each conduction unit 2 is connected to the anode of the voltage stabilizing diode to obtain the breakdown current as the control signal.

[0042] In one embodiment, the overcharge protection circuit is arranged on the substrate 101; the substrate 101 is rectangular, and the two ends are respectively welded to the positive electrode tab A1 and the negative electrode tab A2 to form an electrical connection; the metal strip includes a first metal strip B1 and a second metal strip B2 with different materials; the first metal strip B1 is welded and fixed with the positive electrode tab A1, and the first metal strip B1 has the same material as the positive electrode tab A1; the second metal strip B2 is welded and fixed with the negative electrode tab A2, and the second metal strip B2 is one of copper, nickel, aluminum, and copper-nickel plating, and preferably the second metal strip B2 has the same material as the negative electrode tab A2.

[0043] Specifically, to achieve a more secure welding effect, in this embodiment, the metal foil strip welding method is used to weld and fix the substrate and the tab, and the material of the metal strip is adjusted according to the material of the tab to achieve the same metal welding.

[0044] Specifically, taking the battery with aluminum sheet positive electrode tab and nickel sheet negative electrode tab as an example, in this embodiment, the first metal strip can be selected as a 0.1mm thick, 4mm wide, and 6mm long aluminum strip, which is laser welded to the positive electrode tab A1. The second metal strip is selected as a 0.1mm thick, 4mm wide, and 6mm long nickel strip, which is laser welded to the negative electrode tab A2.

[0045] In practice, the material of the metal strip can be selected from one of copper, aluminum, nickel, copper-nickel plating, or various alloys.

[0046] In one embodiment, as Figure 5 shown, the overcharge prevention module is arranged on the side of the positive electrode tab A1 and the negative electrode tab A2 close to the battery cell; the other side of the positive electrode tab A1 and the negative electrode tab A2 away from the battery cell is respectively provided with a tab rubber 104; the tab rubber 104 is arranged on the outer side of the substrate 101 for heat sealing and fixing with the aluminum-plastic film shell.

[0047] In one embodiment, the substrate 101 is made of epoxy glass cloth material; the printed circuit is formed on the substrate 101 by silver conductive glue or copper block; the devices of the voltage stabilizing diode 1 and the conduction unit 2 are connected to the printed circuit by soldering.

[0048] Specifically, to achieve better compatibility with various battery cell structures, this embodiment uses epoxy fiberglass cloth as the substrate of the substrate 101. Printed circuits and pads are formed on the epoxy fiberglass cloth by printing silver conductive adhesive or copper blocks. The Zener diode 1 and the conducting unit 2 are then soldered and fixed. To meet structural strength requirements, thermally conductive adhesive can be used to bond and cure the components underneath.

[0049] In one embodiment, thermally conductive silicone is also provided on the substrate 101 as an inner encapsulation layer; the thermally conductive silicone covers the upper and lower surfaces of the substrate to ensure complete coverage of the Zener diode 1 and the conducting unit 2, thereby achieving thermal conductivity and sealing and preventing corrosion from contact with electrolyte; an aluminum plate encapsulation is also provided on the outside of the thermally conductive silicone.

[0050] Specifically, to achieve better structural strength, in this embodiment, after the device is soldered onto the substrate 101, thermally conductive silicone is used for curing and fixing to achieve a seal, prevent electrolyte ingress and corrosion, and provide better thermal conductivity to improve the device's ability to carry high currents. Furthermore, aluminum plate encapsulation is used on the substrate 101 to further improve heat dissipation performance.

[0051] Specifically, in order to achieve a better integration effect, in this embodiment, the substrate 101 of the integrated protection circuit is welded and fixed between the positive and negative electrodes with the electrode adhesive 104 as the boundary. This ensures that after the electrodes and the battery cell are welded and integrated, the protection device is placed inside the battery casing, in the space between the battery cell and the electrode adhesive, so that any single battery cell can be overvoltage detected and protected.

[0052] Employing flip-chip packaging and thermal insulation design, it ensures stable operation under 1-5A bypass current. This effectively prevents thermal runaway caused by overcharging, enhancing intrinsic battery safety. It automatically returns to normal operating temperature after overcharging, and the battery can be reused in special circumstances.

[0053] A battery comprising the aforementioned battery tab structure.

[0054] A method for fabricating a battery comprising the above-described battery tab structure; such as Figure 6 As shown, the preparation method includes: Step S1: Welding devices on a substrate to obtain an overcharge protection circuit and fabricating a packaged circuit; Step S2: Welding the packaged circuit to the positive electrode tab and the negative electrode tab respectively to obtain a battery tab structure; Step S3: Fabricating a cell structure and welding the cell structure to the battery tab structure, followed by casing, liquid injection, and formation to obtain a battery.

[0055] Specifically, in order to achieve better manufacturing results, in this embodiment, the above-mentioned protection circuit is integrated into the battery cell tab structure through the above steps.

[0056] Specifically, 1N4732A type voltage regulator diode and 1.5Ω metal film resistor, TIP31C type NPN triode are arranged and connected according to the circuit wiring structure, and inner layer heat-conducting silica gel and outer layer aluminum plate are used for packaging.

[0057] The positive connection piece is selected from an aluminum strip with a thickness of 0.1 mm, a width of 4 mm and a length of 6 mm, and is connected to the positive tab aluminum piece by laser welding; the negative connection piece is selected from a nickel strip with a thickness of 0.1 mm, a width of 4 mm and a length of 6 mm, and is connected to the negative tab nickel piece by laser welding, thereby forming a single electrode tab structure.

[0058] Subsequently, the cell part is made. For example, lithium nickel cobalt manganese oxide (NCM) is used as the positive electrode, and silicon carbon is used as the negative electrode to perform slurry preparation, coating, rolling and lamination according to the conventional process to make a dry cell, and then the positive and negative electrodes of the electrode tab are welded on the dry cell according to the sequence of the electrode tab to form a complete cell structure.

[0059] According to the cell structure, an aluminum-plastic film is selected for packaging according to the cell specification, and then the cell is injected with electrolyte and formed, and finally a battery product is obtained.

[0060] The above battery product is used as Example 1.

[0061] Example 2: The overcharge prevention module, integrated overvoltage protection tab and single battery are prepared according to Example 1, and the difference is that the discharge current is improved by using two triodes in parallel, wherein the 1.5Ω current limiting resistor is two and the TIP31C type NPN triode is two, which are arranged and connected according to the wiring structure shown in Figure 4 .

[0062] Comparative Example 1: The soft package battery is prepared according to Example 1, and the difference is that the comparative example uses a conventional battery tab without integrating the overcharge prevention module.

[0063] Overcharge tests are performed on the batteries of Examples 1, 2 and Comparative Example, respectively. The batteries are first fully charged, and then overcharged, wherein Example 1 is tested at 1C constant current overcharge, Example 2 is tested at 2C constant current overcharge, and Comparative Example is tested at 1C constant current overcharge. The overcharge cutoff condition is that the overcharge capacity reaches 4 Ah or fire and explosion occurs, and the diode breakdown voltage, the highest overcharge voltage and whether fire and explosion occur are recorded.

[0064]

[0065] From the above table, the batteries of Examples 1 and 2 did not catch fire and explode, while the batteries of the comparative examples caught fire. The breakdown voltages of the diodes in the two examples are different, because there is a certain tolerance in the breakdown voltage of the voltage stabilizing diode, and even the breakdown voltages of the diodes in the same batch will not be completely consistent, and usually within a certain range. In this embodiment, the minimum breakdown voltage of the voltage stabilizing diode is 4.465 V, and the maximum breakdown voltage is 4.935 V. Usually, within this voltage range, the lithium ion battery has been significantly overcharged, but generally does not catch fire and explode. If the overcharging continues to exceed 5 V, the risk of fire will be greatly increased.

[0066] The breakdown voltage of the diode in Example 1 is about 4.585 V, the current limiting resistor is 1.5 Ω, the maximum shunt current is greater than 2 Ah, which is much lower than the rated current 3 A of the triode, and much lower than the peak current 5 A. The 1C overcharge current is 2 A, so the overcharge protection module continues to discharge 2 A to prevent the battery voltage from continuing to rise.

[0067] The breakdown voltage of the diode in Example 2 is 4.653 V, the current limiting resistor is 1.5 Ω, and the maximum shunt current of the single triode also exceeds 2 A. However, since the battery is charged at 2C, the current reaches 4 A, which has exceeded the rated current of a single triode, and long-term operation may cause overheating risk. Therefore, in this embodiment, two triodes are connected in parallel to prevent the discharge current of a single triode from exceeding the rated current. Two triodes are activated by the same voltage stabilizing diode, which can eliminate the problem of inconsistent breakdown voltages of different diodes.

[0068] The comparative examples did not use the overcharge protection module, so the battery continued to be overcharged, and the battery had serious lithium precipitation, gas production, and heating, which caused short circuit and thermal runaway, and further caused fire and even explosion.

[0069] It should be noted that the charge and discharge intervals of different battery systems are different, but for lithium iron phosphate, ternary, lithium cobaltate or other systems, the general charging cutoff voltage is generally not more than 4.5 V, and even if overcharged below this voltage, fire and explosion will not occur. In addition, different voltage protection discharge can be achieved by replacing diodes with different breakdown voltages, so the present application is suitable for various battery systems and has the same effect.

[0070] For batteries of different capacities and different charge rates, the charging current may vary greatly. The present application can discharge current by connecting multiple triodes in parallel. The rated current of a single triode is 3 A, and the maximum current reaches 5 A. By connecting 5 triodes in parallel, a current discharge capacity of 15 A and a maximum of 25 A can be achieved. In addition, by replacing high-power triodes, they can be used for large-capacity batteries. Therefore, the present application can be applied to batteries of various capacities.

[0071] The above merely preferred embodiments of the present application and are not intended to limit the embodiments and protection scope of the present application. Those skilled in the art should be able to understand that any equivalent substitutions and obvious changes made according to the present application description and drawings should be included in the protection scope of the present application.

Claims

1. A battery tab structure with integrated overvoltage protection, comprising a positive tab and a negative tab, characterized in that, An overcharge protection circuit is connected between the positive and negative electrodes. The overcharge protection circuit includes a Zener diode and at least one conducting unit. The cathode of the Zener diode is connected to the positive electrode, and the anode of the Zener diode is connected to the control terminal of the conducting unit and is connected to the negative electrode. The input terminal of the conducting unit is connected to the positive electrode, and the output terminal of the conducting unit is connected to the negative electrode. The breakdown voltage of the Zener diode is determined according to the overvoltage protection value of the battery, and a control signal is input to the conducting unit when reverse breakdown occurs, so that the conducting unit constructs a shunt channel from the positive electrode to the negative electrode.

2. The battery tab structure according to claim 1, characterized in that, The conduction unit includes: a current-limiting resistor, the first end of which is connected to the input terminal of the conduction unit; a transistor, the collector of which is connected to the second end of the current-limiting resistor, the emitter of which is connected to the output terminal of the conduction unit; and the base of which is connected to the control terminal of the conduction unit.

3. The battery tab structure according to claim 1, characterized in that, The overcharge protection circuit is disposed on the substrate; the substrate is rectangular, and its two ends are electrically connected to the positive electrode tab and the negative electrode tab respectively by metal strips.

4. The battery tab structure according to claim 3, characterized in that, The metal strip includes a first metal strip and a second metal strip with different materials; the first metal strip is welded and fixed to the positive electrode tab, and the first metal strip has the same material as the positive electrode tab; the second metal strip is welded and fixed to the negative electrode tab, and the second metal strip has the same material as the negative electrode tab.

5. The battery tab structure according to claim 3, characterized in that, The substrate is disposed on the side of the positive electrode tab and the negative electrode tab that are close to the battery cell; tab adhesive is disposed on the other side of the positive electrode tab and the negative electrode tab that are away from the battery cell; the tab adhesive is disposed on the outer side of the substrate.

6. The battery tab structure according to claim 3, characterized in that, The substrate is made of epoxy fiberglass cloth; a printed circuit is formed on the substrate using silver conductive adhesive or copper blocks; the Zener diode and the device of the conduction unit are connected to the printed circuit by solder.

7. The battery tab structure according to claim 6, characterized in that, The substrate is further provided with thermally conductive silicone as an inner encapsulation layer; the thermally conductive silicone covers the upper and lower surfaces of the substrate; and an aluminum plate encapsulation is provided on the outside of the thermally conductive silicone.

8. A battery, characterized in that, Includes the battery tab structure as described in any one of claims 1-7.

9. A preparation method, characterized in that, The method for manufacturing a battery comprising a battery tab structure as described in any one of claims 1-7 includes: step S1: welding devices on a substrate to obtain an overcharge protection circuit and fabricating a packaged circuit; step S2: welding the packaged circuit to a positive electrode tab and a negative electrode tab respectively to obtain the battery tab structure; step S3: fabricating a cell structure and welding the cell structure to the battery tab structure, followed by casing, liquid injection, and formation to obtain the battery.

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