Battery cover plate and lithium ion battery

Abstract

The utility model relates to a battery cover plate which is arranged at an opening position of a shell of a lithium ion battery and comprises a cover plate main body, a pole and a high-temperature discharging device, the pole and the high-temperature discharging device are both arranged on the cover plate main body, the high-temperature discharging device comprises an electric connecting piece and a safety piece, the electric connecting piece is electrically connected with the pole, and the safety piece is arranged on the cover plate main body. The safety piece is electrically connected with the cover plate main body; when the battery is at high temperature, the safety piece is electrically connected with the electric connecting piece; and the high-temperature discharging device communicates the positive electrode and the negative electrode of the battery for discharging. The utility model also relates to a lithium ion battery. When the temperature of the battery is high, the battery is subjected to rapid discharge reaction, and the thermal safety performance is high.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion batteries, and in particular to a battery cover and a lithium-ion battery. Background Technology

[0002] With the rapid development of electronic devices, electric vehicles, and energy storage systems, lithium-ion batteries are widely used due to their high energy density, long cycle life, and low self-discharge rate. However, lithium-ion batteries may encounter overcharging, over-discharging, short circuits, or high external temperatures during use. These factors can cause a rapid rise in internal and external temperatures, leading to thermal runaway. Thermal runaway not only degrades battery performance but can also cause fires or even explosions in severe cases, posing a threat to user safety.

[0003] To ensure the safe operation of lithium-ion batteries, the industry has adopted various measures to monitor and manage their operating status. For example, integrating temperature sensors to monitor temperature changes within the battery pack and setting appropriate temperature control strategies; and utilizing battery management systems (BMS) to achieve real-time monitoring and adjustment of parameters such as battery voltage and current.

[0004] Nevertheless, existing solutions often have certain limitations. For example, traditional temperature control methods can usually only respond after the fact, and cannot effectively prevent potential risks in a timely manner under extreme conditions; moreover, some protection mechanisms are irreversible once triggered, affecting the normal operation of the entire system. Utility Model Content

[0005] To address the technical problems existing in the prior art, the purpose of this utility model is to provide a battery cover and a lithium-ion battery, which enables the battery to undergo a rapid discharge reaction when the battery temperature is high, resulting in high thermal safety performance.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A battery cover plate is installed at the opening of the casing of a lithium-ion battery. It includes a cover plate body, terminals, and a high-temperature discharge device. Both the terminals and the high-temperature discharge device are installed on the cover plate body. The high-temperature discharge device includes an electrical connector and a safety component. The electrical connector is electrically connected to the terminals, and the safety component is electrically connected to the cover plate body. When the battery is at a high temperature, the safety component is electrically connected to the electrical connector, and the high-temperature discharge device discharges by connecting the positive and negative terminals of the battery.

[0008] As a preferred embodiment, two battery covers are installed on the battery casing, and the terminals are either positive or negative terminals. One cover body is fitted with the positive terminal, and the other cover body is fitted with the negative terminal. The positive and negative terminals are insulated from each other. When the battery is at a high temperature, the positive terminal, the high-temperature discharge device, the cover body, the casing, the other cover body, the other high-temperature discharge device, and the negative terminal are connected in sequence for discharge.

[0009] As a preferred embodiment, only one battery cover is installed on the battery casing, and there are two terminals, namely a positive terminal and a negative terminal. The positive terminal and the negative terminal are installed on the cover body at the same time, and the positive terminal and the negative terminal are insulated from each other. There are two high-temperature discharge devices, one of which is electrically connected to the positive terminal and the other of which is electrically connected to the negative terminal. When the battery is at a high temperature, the positive terminal, the high-temperature discharge device, the cover body, the other high-temperature discharge device, and the negative terminal are connected in sequence to discharge.

[0010] As a preferred embodiment, the electrical connector includes a first electrical connector, a resistor, and a second electrical connector connected in series and electrically connected. The first electrical connector is electrically connected to the pole. The safety component is a shape memory alloy, which is installed on the outer surface of the cover plate body. The shape memory alloy arches away from the outer surface of the cover plate body, and a gap is formed between the second electrical connector and the shape memory alloy. At high temperatures, the shape memory alloy deforms and arches to a greater height, making contact with the second electrical connector and forming an electrical connection.

[0011] As a preferred option, when the battery is operating at a low normal operating temperature, the gap distance is 0.5mm-1mm.

[0012] As a preferred option, the resistance value is 0.03Ω-1Ω.

[0013] As a preferred option, the safety component is an NTC resistor, which is a resistor with a negative temperature coefficient. The NTC resistor is mounted on the outer surface of the cover plate body and is electrically connected to the electrical connector.

[0014] As a preferred option, the NTC resistor has a resistance of >1MΩ when the temperature is <60℃ and a resistance of 0.03Ω-1Ω when the temperature is >100℃.

[0015] As a preferred embodiment, the high-temperature discharge device also includes an insulating support plate, with the end of the electrical connector away from the electrode post overlapping the top of the insulating support plate.

[0016] A lithium-ion battery includes a casing and a battery cover, the battery cover being disposed at an opening in the casing, and a battery cell structure being disposed inside the casing.

[0017] This utility model has the following advantages:

[0018] (1) The high-temperature discharge device of this utility model connects the positive and negative terminals of the battery to discharge when the battery temperature rises. The discharge reaction quickly reduces the energy of the battery, thereby preventing the risk of fire and explosion caused by battery abuse.

[0019] (2) The outer surface of the battery cover of this utility model is provided with a safety component. When the battery temperature rises, the safety component changes so that the high-temperature discharge device connects the positive and negative terminals of the battery to achieve discharge.

[0020] (3) When the safety component is a shape memory alloy, it arches outward at high temperature and connects to the second electrical connector to realize the connection of the discharge circuit; when the temperature drops, the shape memory alloy returns to its original shape. The shape memory alloy can be recycled, which improves the battery's service life.

[0021] (4) When the safety component is an NTC resistor, the NTC resistor is a resistor with a negative temperature coefficient. When the battery is working normally, the temperature of the cover body is low and the resistance of the NTC resistor is large, so that the electrical connector and the cover body are equivalent to an insulated state. When the temperature of the cover body rises, the resistance of the NTC resistor decreases with the rise in temperature, thus realizing the connection of the discharge circuit. The NTC resistor can be recycled. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a top view of Example 1.

[0024] Figure 2 for Figure 1 AA sectional view.

[0025] Figure 3 for Figure 2 Enlarged view of point B.

[0026] Figure 4 This is a structural disassembly diagram of Example 1.

[0027] Figure 5 This is a top view of Example 2.

[0028] Figure 6 for Figure 5 CC section view.

[0029] Figure 7 for Figure 6 Enlarged view of point D.

[0030] Figure 8 This is a structural disassembly diagram of Example 2.

[0031] Figure 9 This is a schematic diagram of the structure of Example 3.

[0032] Figure 10 This is a schematic diagram of the structure of Example 4.

[0033] The components include: 1. Cover plate body; 2. Pole post; 3. Electrical connector; 4. First electrical connector; 5. Resistor; 6. Second electrical connector; 7. Shape memory alloy; 8. NTC resistor; 9. Insulating support plate; 10. Electrical lead block; 11. Connector. Detailed Implementation

[0034] The technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0035] Example 1

[0036] like Figures 1-4 As shown, a battery cover is installed at the opening of a lithium-ion battery casing. The casing is made of a conductive material. The battery cover includes a cover body 1, terminals 2, and a high-temperature discharge device. The cover body 1 is made of a conductive material. The terminals 2 and the high-temperature discharge device are both mounted on the cover body 1. The high-temperature discharge device includes an electrical connector 3 and a safety component. The electrical connector 3 is electrically connected to the terminals 2, and the safety component is electrically connected to the cover body 1. An electrical lead-out block 10 is fitted onto the main body of the terminals 2. The terminals 2, the electrical lead-out block 10, and the electrical connector 3 are sequentially electrically connected. When the battery is at a high temperature, the safety component is electrically connected to the electrical connector 3, and the high-temperature discharge device discharges by connecting the positive and negative terminals of the battery. The battery cover also includes an explosion-proof valve and a liquid injection hole. Two battery covers are installed on the battery casing. Each battery cover includes a high-temperature discharge device. The terminal 2 is either a positive terminal or a negative terminal. One cover body 1 is equipped with the positive terminal, and the other cover body 1 is equipped with the negative terminal. The positive terminal and the negative terminal are insulated from each other. When the battery is at a high temperature, the positive terminal, the high-temperature discharge device, the cover body 1, the casing, the other cover body 1, the other high-temperature discharge device, and the negative terminal are connected in sequence to form a discharge circuit for discharge.

[0037] The cover plate body 1 and the electrode post 2 are connected by a connector 1, and the cover plate body 1 and the electrode post 2 are connected by a connector 11 with a resistance value of 100Ω or higher. The connector 11 is a high-resistance resistor or an insulator. The cover plate body 1 and the electrode post 2 are not directly electrically connected. The resistance value of the high-resistance resistor is 100Ω-10000Ω, and the material of the resistor can be PPS, PP, or PET doped with carbon powder. The resistance value of the insulator is ≥10Ω. 15 Ω; Specifically, there are two connection methods between the cover plate body 1 and the terminal 2: One connection method is that the positive terminal is connected to the cover plate body 1 through a high-resistance resistor, and the negative terminal is connected to the cover plate body 1 through an insulator. In this connection method, the battery casing carries a weak positive charge to prevent casing corrosion. This is because casing corrosion is generally caused by the low negative electrode voltage of the aluminum casing, which allows lithium ions to embed into the aluminum casing and form an aluminum-lithium alloy, causing corrosion. When the casing carries a weak positive charge, lithium ions cannot embed into the aluminum casing, thus preventing casing corrosion. The other connection method is that the positive terminal is connected to the cover plate body 1 through an insulator, and the negative terminal is connected to the cover plate body 1 through an insulator.

[0038] The electrical connector 3 includes a first electrical connector 4, a resistor 5, and a second electrical connector 6 connected in series and electrically. The first electrical connector 4 is electrically connected to the terminal 2 through the electrical lead block 10. Both the first electrical connector 4 and the second electrical connector 6 are made of aluminum or aluminum alloy. The resistor 5 is a common resistance wire or ceramic resistor. In this embodiment, the discharge load is the resistor 5, which has a resistance of 0.03Ω-1Ω. The safety component is a shape memory alloy 7, which is sheet-shaped and mounted on the outer surface of the cover plate body 1. The shape memory alloy 7 arches away from the outer surface of the cover plate body 1. A gap is formed between the second electrical connector 6 and the shape memory alloy 7. When the normal operating temperature of the battery is low, the gap distance is 0.5mm-1mm. When the battery is in normal use, the second electrical connector 6 does not contact the shape memory alloy 7. At high temperatures, the shape memory alloy 7 deforms and arches to a greater height, contacting the second electrical connector 6. The second electrical connector 6 and the shape memory alloy 7 are electrically connected, thereby connecting the high-temperature discharge device to the discharge circuit, connecting the positive and negative terminals of the battery to discharge, and making the cover plate body 1 and the battery casing energized.

[0039] The electrical connector 3 is either straight or concave, bent towards the safety component. In this embodiment, the second electrical connector 6 is preferably concave towards the shape memory alloy 7. The second electrical connector 6 is inverted "V" shape. The high-temperature discharge device also includes an insulating support plate 9, which is made of high-temperature resistant plastic, such as PP, PET, or PPS. The end of the electrical connector 3 away from the pole 2 overlaps the top of the insulating support plate 9. The insulating support plate 9 lifts the end of the electrical connector 3 to ensure that the electrical connector 3 will not sag due to gravity and contact the cover plate body 1, thus causing a circuit break.

[0040] The high battery temperature mentioned in this embodiment refers to a battery temperature higher than 100°C.

[0041] When the battery is working normally, the high-temperature discharge device of the battery cover forms an insulating structure between the battery terminal 2 and the cover body 1. When the battery is abused and out of control, the battery temperature rises sharply, the temperature of the cover body 1 rises, and the high-temperature discharge device is activated, connecting the positive and negative terminals to the cover body 1 respectively, thereby causing the battery to short-circuit and discharge. The discharge reaction quickly reduces the battery energy, thus preventing the battery from catching fire or exploding when abused, and improving the battery safety.

[0042] Example 2

[0043] like Figures 5-8 As shown, the difference between this embodiment and embodiment one is that the safety component is an NTC resistor 8, which is a resistor with a negative temperature coefficient. The NTC resistor 8 is installed on the outer surface of the cover plate body 1. In this embodiment, the electrical connector 3 is preferably inverted "U" shape. The innermost side of the electrical connector 3 is in contact with the NTC resistor 8, and the NTC resistor 8 is electrically connected to the electrical connector 3.

[0044] When the battery is operating normally, its temperature is <60℃. When the temperature is <60℃, the resistance of the NTC resistor 8 is >1MΩ, making the electrical connector 3 and the cover body 1 equivalent to an insulating state. When the battery temperature rises, the temperature of the cover body 1 also rises, and the resistance of the NTC resistor 8 decreases rapidly with the increase in temperature. When the temperature is >100℃, its resistance is 0.03Ω-1Ω, thereby enabling the battery positive terminal, electrical connector 3, NTC resistor 8, cover body 1, shell, cover body 1, NTC resistor 8, electrical connector 3, and battery negative terminal to conduct in sequence, thereby realizing battery discharge. In this embodiment, the discharge load is the NTC resistor 8.

[0045] Example 3

[0046] like Figure 9 As shown, this embodiment differs from Embodiment 1 in that only one battery cover is installed on the battery casing, and there are two terminals 2, which are the positive terminal and the negative terminal respectively. The positive terminal and the negative terminal are installed on the cover body 1 at the same time, and the positive terminal and the negative terminal are insulated from each other. There are two high-temperature discharge devices, one electrical connector 3 is electrically connected to the positive terminal, and the other electrical connector 3 is electrically connected to the negative terminal. When the battery is at high temperature, the positive terminal, the high-temperature discharge device, the cover body 1, the other high-temperature discharge device, and the negative terminal are connected and discharged in sequence.

[0047] Example 4

[0048] like Figure 10As shown, this embodiment differs from Embodiment 1 in that only one battery cover is installed on the battery casing, and there are two terminals 2, which are the positive terminal and the negative terminal respectively. The positive terminal and the negative terminal are installed on the cover body 1 at the same time, and the positive terminal and the negative terminal are insulated from each other. There are two high-temperature discharge devices, one electrical connector 3 is electrically connected to the positive terminal, and the other electrical connector 3 is electrically connected to the negative terminal. When the battery is at high temperature, the positive terminal, the high-temperature discharge device, the cover body 1, the other high-temperature discharge device, and the negative terminal are connected and discharged in sequence.

[0049] The safety component is an NTC resistor 8, which is a resistor with a negative temperature coefficient. The NTC resistor 8 is installed on the outer surface of the cover plate body 1. In this embodiment, the electrical connector 3 is preferably inverted "U" shape. The innermost side of the electrical connector 3 is in contact with the NTC resistor 8, and the NTC resistor 8 is electrically connected to the electrical connector 3.

[0050] When the battery is operating normally, its temperature is <60℃. When the temperature is <60℃, the resistance of the NTC resistor 8 is >1MΩ, making the electrical connector 3 and the cover body 1 equivalent to an insulating state. When the battery temperature rises, the temperature of the cover body 1 also rises, and the resistance of the NTC resistor 8 decreases rapidly with the increase in temperature. When the temperature is >100℃, its resistance is 0.03Ω-1Ω, thereby enabling the battery positive terminal, electrical connector 3, NTC resistor 8, cover body 1, shell, cover body 1, NTC resistor 8, electrical connector 3, and battery negative terminal to conduct in sequence, thereby realizing battery discharge. In this embodiment, the discharge load is the NTC resistor 8.

[0051] Example 5

[0052] A lithium-ion battery includes a casing and a battery cover plate according to Embodiment 1, Embodiment 2, Embodiment 3, or Embodiment 4. The battery cover plate is disposed on the opening of the casing, and a cell structure is disposed inside the casing.

[0053] When the battery cell structure experiences thermal runaway, the ambient temperature of the cell structure rises, causing the battery to self-discharge rapidly, reducing the battery's state of charge, thereby preventing thermal runaway and inhibiting heat propagation.

[0054] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the substance and scope of the present invention. Various modifications made by those skilled in the art to the above embodiments after reading this specification are all within the scope of protection of the present invention.

Claims

1. A battery cover plate, installed at the opening of a lithium-ion battery casing, characterized in that: It includes a cover plate body (1), a terminal post (2) and a high-temperature discharge device. The terminal post (2) and the high-temperature discharge device are both installed on the cover plate body (1). The high-temperature discharge device includes an electrical connector (3) and a safety component. The electrical connector (3) is electrically connected to the terminal post (2), and the safety component is electrically connected to the cover plate body (1). When the battery is at a high temperature, the safety component is electrically connected to the electrical connector (3), and the high-temperature discharge device connects the positive and negative terminals of the battery for discharge.

2. The battery cover according to claim 1, characterized in that: Two battery covers are installed on the battery casing. The terminal (2) is either a positive terminal or a negative terminal. One cover body (1) is equipped with the positive terminal, and the other cover body (1) is equipped with the negative terminal. The positive terminal and the negative terminal are insulated from each other. When the battery is at high temperature, the positive terminal, the high temperature discharge device, the cover body (1), the casing, the other cover body (1), the other high temperature discharge device, and the negative terminal are connected in sequence for discharge.

3. A battery cover according to claim 1, characterized in that: There is only one battery cover plate installed on the battery casing. There are two terminals (2), which are positive and negative terminals respectively. The positive and negative terminals are installed on the cover plate body (1) at the same time, and the positive and negative terminals are insulated from each other. There are two high-temperature discharge devices. One electrical connector (3) is electrically connected to the positive terminal, and the other electrical connector (3) is electrically connected to the negative terminal. When the battery is at high temperature, the positive terminal, the high-temperature discharge device, the cover plate body (1), the other high-temperature discharge device, and the negative terminal are connected and discharged in sequence.

4. A battery cover according to claim 1, characterized in that: The electrical connector (3) includes a first electrical connector (4), a resistor (5), and a second electrical connector (6) connected in series and electrically. The first electrical connector (4) is electrically connected to the pole (2). The safety component is a shape memory alloy (7). The shape memory alloy (7) is installed on the outer surface of the cover plate body (1). The shape memory alloy (7) arches away from the outer surface of the cover plate body (1). A gap is formed between the second electrical connector (6) and the shape memory alloy (7). At high temperature, the shape memory alloy (7) deforms and arches to a greater height to contact and electrically connect with the second electrical connector (6).

5. A battery cover according to claim 4, characterized in that: When the battery is operating at a low normal temperature, the gap distance is 0.5mm-1mm.

6. A battery cover according to claim 4, characterized in that: The resistance of resistor (5) is 0.03Ω-1Ω.

7. A battery cover according to claim 1, characterized in that: The safety component is an NTC resistor (8), which is a resistor with a negative temperature coefficient. The NTC resistor (8) is installed on the outer surface of the cover body (1) and is electrically connected to the electrical connector (3).

8. A battery cover according to claim 7, characterized in that: The resistance of the NTC resistor (8) is >1MΩ when the temperature is <60℃; and 0.03Ω-1Ω when the temperature is >100℃.

9. A battery cover according to claim 1, characterized in that: The high-temperature discharge device also includes an insulating support plate (9), and the end of the electrical connector (3) away from the pole (2) is attached to the top of the insulating support plate (9).

10. A lithium-ion battery, characterized in that: The device includes a housing and a battery cover as described in any one of claims 1-9, wherein the battery cover is disposed over the opening of the housing, and a battery cell structure is disposed inside the housing.

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