Detection device, lithium battery and electronic equipment

Abstract

The utility model provides a detection device, a lithium battery and electronic equipment. The detection device comprises a first conductive part, a second conductive part and a target structure, the first conductive piece has a first expansion coefficient; the second conductive part has a second expansion coefficient different from that of the first conductive part, the first conductive part and the second conductive part are connected to form a thermocouple, and the thermocouple is arranged on the surface of the cell and used for detecting the temperature of the cell; the target structure is arranged on the first conductive part and / or the second conductive part, and the target structure can enable the first conductive part or the second conductive part to be broken under the condition that the battery cell expands to a target threshold value, so that electric signal transmission of the thermocouple is interrupted.

Description

Technical Field

[0001] This application relates to the field of electronic equipment technology, and in particular to a detection device, a lithium battery, and an electronic device. Background Technology

[0002] Lithium battery cells will gradually expand with long-term use, especially at the end of the battery's lifespan. Severe expansion can cause them to burst open the casing of electronic devices.

[0003] In existing technologies, software algorithms are used to detect battery lifespan, but the accuracy of these algorithms is low, and their compatibility is poor, making them unsuitable for testing all types of battery cells. Utility Model Content

[0004] This disclosure provides a detection device, a lithium battery, and an electronic device, the technical solutions of which are as follows:

[0005] In a first aspect, this disclosure provides a detection apparatus, comprising:

[0006] A first conductive element, wherein the first conductive element has a first coefficient of thermal expansion;

[0007] The second conductive element has a second coefficient of thermal expansion different from that of the first conductive element, and the first conductive element and the second conductive element are connected to form a thermocouple. The thermocouple is disposed on the surface of the battery cell for detecting the temperature of the battery cell.

[0008] A target structure is disposed on the first conductive element and / or the second conductive element, the target structure being capable of causing the first conductive element or the second conductive element to break when the battery cell expands to a target threshold, thereby interrupting the electrical signal transmission of the thermocouple.

[0009] In some embodiments, the target structure includes at least one groove structure disposed on the first conductive element and / or the second conductive element, the groove structure being disposed in the thickness direction of the first conductive element and / or the second conductive element to reduce the area of ​​the first conductive element and / or the second conductive element in the radial cross section.

[0010] In some embodiments, the first conductive element and / or the second conductive element are multiple groups and are spaced apart; and / or, both the first conductive element and the second conductive element are provided with multiple groove structures; and / or, the number of groove structures provided on the first conductive element is different from the number of groove structures provided on the second conductive element.

[0011] In some embodiments, the first conductive element is in multiple groups, the second conductive element is in one group, the target structure is disposed on the first conductive element, and the coefficient of thermal expansion of the first conductive element is smaller than the coefficient of thermal expansion of the second conductive element.

[0012] In some embodiments, the second conductive element is in multiple groups, the first conductive element is in one group, the target structure is disposed on the second conductive element, and the expansion coefficient of the second conductive element is smaller than the expansion coefficient of the first conductive element.

[0013] In some embodiments, the first conductive element and the second conductive element are multiple sets, and are respectively connected to each other, and the target structure is disposed on the conductive material with the smaller coefficient of thermal expansion among the first conductive element and the second conductive element.

[0014] In some embodiments, the first conductive element and the second conductive element are flat.

[0015] In a second aspect, this disclosure provides a lithium battery, including a cell and a detection device; the detection device includes a first conductive element having a first coefficient of thermal expansion; a second conductive element having a second coefficient of thermal expansion different from that of the first conductive element, and the first conductive element and the second conductive element are connected to form a thermocouple, the thermocouple being disposed on the surface of the cell for detecting the temperature of the cell;

[0016] A target structure is disposed on the first conductive element and / or the second conductive element, the target structure being capable of causing the first conductive element or the second conductive element to break when the battery cell expands to a target threshold, thereby interrupting the electrical signal transmission of the thermocouple.

[0017] In some embodiments, an adhesive layer is provided between the surface of the battery cell and the thermocouple.

[0018] In a third aspect, this disclosure proposes an electronic device, including a lithium battery;

[0019] The lithium battery includes a cell and a detection device; the detection device includes a first conductive element having a first coefficient of expansion; a second conductive element having a second coefficient of expansion different from that of the first conductive element, and the first conductive element and the second conductive element are connected to form a thermocouple, the thermocouple being disposed on the surface of the cell for detecting the temperature of the cell;

[0020] A target structure is disposed on the first conductive element and / or the second conductive element, the target structure being capable of causing the first conductive element or the second conductive element to break when the battery cell expands to a target threshold, thereby interrupting the electrical signal transmission of the thermocouple.

[0021] The above description is only an overview of the technical solution of this disclosure. In order to better understand the technical means of this disclosure and to implement it in accordance with the contents of the specification, the preferred embodiments of this disclosure are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in this disclosure 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 disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the assembly of the testing device and the battery cell provided in this disclosure.

[0024] Figure 2 A side view of the testing device and battery cell assembly provided in this disclosure;

[0025] Figure 3 The schematic diagram shows that the first conductive element and the second conductive element in the detection device provided in this disclosure are multiple sets and are arranged on the battery cell.

[0026] Figure 4 The schematic diagram of the structure of the detection device provided in this disclosure, in which the first conductive element is multiple sets connected to a second conductive element and disposed on the battery cell;

[0027] Figure 5 The schematic diagram shows that the second conductive element of the detection device provided in this disclosure is a multi-group structure connected to a group of first conductive elements and disposed on the battery cell;

[0028] Figure 6 This is a schematic diagram showing the structure of multiple testing devices and multiple sets of battery cells provided in this disclosure.

[0029] Explanation of reference numerals in the attached figures:

[0030] 00. Battery cell; 10. First conductive component; 20. Second conductive component; 30. Target structure; 40. Adhesive layer; 50. PCB board. Detailed Implementation

[0031] The embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of this disclosure by way of example, but should not be used to limit the scope of this disclosure. This disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0032] These embodiments are provided to make the disclosure thorough and complete, and to fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0033] It should be noted that, in the description of this disclosure, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationship, are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0034] Furthermore, the terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the permissible margin of error. "Parallel" is not strictly parallel, but within the permissible margin of error. Terms such as "including" or "contains" mean that the element preceding the word encompasses the element listed after the word, and do not exclude the possibility of encompassing other elements as well.

[0035] It should also be noted that, in the description of this disclosure, unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure depending on the specific circumstances. When a particular device is described as being located between a first device and a second device, an intermediary device may or may not be present between the particular device and the first or second device.

[0036] All terms used in this disclosure have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0037] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0038] In the first aspect, such as Figure 1-2 As shown, this disclosure provides a detection device, including: a first conductive element 10, a second conductive element 20, and a target structure 30;

[0039] The first conductive element 10 has a first coefficient of thermal expansion;

[0040] The second conductive element 20 has a second expansion coefficient different from that of the first conductive element 10, and the first conductive element 10 and the second conductive element 20 are connected to form a thermocouple. The thermocouple is disposed on the surface of the cell 00 for detecting the temperature of the cell 00.

[0041] The target structure 30 is disposed on the first conductive element 10 and / or the second conductive element 20. The target structure 30 enables the first conductive element 10 or the second conductive element 20 to break when the cell 00 expands to the target threshold, thereby interrupting the electrical signal transmission of the thermocouple.

[0042] Understandably, this disclosure proposes a device for detecting the temperature of a battery cell 00 and automatically interrupting the transmission of electrical signals when the battery cell 00 expands to an unsafe level. The first conductive element 10 has a specific first expansion coefficient, and the second conductive element 20 has a different (which may be higher or lower) second expansion coefficient compared to the first conductive element 10.

[0043] A thermocouple is formed by connecting the first conductive element 10 and the second conductive element 20. A thermocouple is a temperature sensor that can convert temperature differences into electrical signals, thereby enabling the monitoring of the surface temperature of the battery cell 00. By directly mounting the thermocouple on the surface of the battery cell 00, the operating temperature of the battery cell 00 can be accurately detected.

[0044] The target structure 30 can be understood as a structural weak point, resulting in low connection strength between the first conductive element 10 and the second conductive element 20, making it prone to breakage due to external factors. For example, it can be formed by machining small holes or creating grooves in thinned areas. The target structure 30 is located on the first conductive element 10 and / or the second conductive element 20, and is used to cause one of the conductive materials to break when the cell 00 expands to a preset safety threshold, thus preventing dangerous situations that may be caused by excessive expansion of the cell 00. Once the conductive material breaks, the electrical signal transmission of the thermocouple is interrupted, which can trigger further safety response measures, such as cutting off the power supply or issuing an alarm.

[0045] Wherein, the first expansion coefficient and the second expansion coefficient can be thermal expansion coefficients, which can be the rate of change of the length, area or volume of the first conductive element 10 and the second conductive element 20 when the temperature changes.

[0046] For example, when the detection device is monitoring the temperature of the battery cell 00 and triggers the safety mechanism at high temperature, the first conductive element 10 can be copper and the second conductive element 20 can be nickel. A target structure 30 can be set on the first conductive element 10 (copper). When the temperature of the surface of the battery cell 00 is too high, causing the copper to expand significantly, the target structure 30 will break.

[0047] A thermocouple is formed by connecting copper and nickel to monitor the temperature of cell 00 in real time. When the temperature of cell 00 reaches a certain threshold (e.g., exceeding 80°C), the thermal expansion of copper is much greater than that of nickel, causing the weak point of the target structure 30 to break, interrupting the thermocouple signal, and thus triggering an alarm to provide a risk warning.

[0048] The first expansion coefficient and the second expansion coefficient can also be elastic expansion coefficients, which can be understood as the degree of elastic deformation of the first conductive element 10 and the second conductive element 20 under the action of external force. For example, the first conductive element 10 can be aluminum and the second conductive element 20 can be steel. Aluminum has a low elastic modulus and is easy to undergo elastic deformation.

[0049] The target structure 30 is placed on the first conductive element 10. When the cell 00 is subjected to pressure due to excessive expansion, the aluminum cantilever beam reaches its yield strength and breaks, interrupting the thermocouple circuit and issuing a warning signal.

[0050] The first and second expansion coefficients can also be pressure expansion coefficients, which refer to the degree to which the volume of a material changes with the pressure applied externally. For battery systems, especially battery packs operating in high-pressure environments, pressure-sensitive materials can be used to create detection devices. When the internal pressure of the battery rises to a dangerous level, the target structure 30 will undergo permanent deformation or fracture, thus providing a risk warning.

[0051] For example, the detection device monitors changes in the gas pressure inside the battery cell to prevent overpressure from causing danger.

[0052] The first conductive component 10 can be made of titanium alloy. Titanium alloy has strong compressive strength, but it will undergo plastic deformation under extremely high pressure.

[0053] The second conductive element 20 can be made of silver, which has good conductivity and low compressive strength.

[0054] A target structure 30 is provided on the first conductive element 10, for example, a thin film structure (such as a diaphragm with a thickness of tens of micrometers) is provided on a titanium alloy material. When the internal pressure of the cell 00 rises to a certain threshold, the thin film ruptures.

[0055] A thermocouple is formed by connecting titanium alloy and silver, and a titanium alloy film is used as a pressure sensor. When the internal pressure of the cell exceeds the safe range (e.g., reaching 10 atm), the titanium alloy film ruptures, causing the thermocouple signal to be interrupted, thereby providing a risk warning.

[0056] This detection device can not only monitor the temperature of the battery cell, but also take proactive power-off measures when potential hazards are detected (such as abnormal cell 00, abnormal internal pressure, or excessive expansion) to protect the entire system from damage. It can improve the safety of the battery system and prevent excessive cell expansion from affecting the appearance of electronic devices, such as causing the casing to bulge.

[0057] The detection device can be applied to electric vehicles, smartphones, laptops, and other scenarios that rely on high-efficiency batteries.

[0058] In some embodiments, such as Figure 2 As shown, the target structure 30 includes at least one groove structure disposed on the first conductive member 10 and / or the second conductive member 20. The groove structure is disposed in the thickness direction of the first conductive member 10 and / or the second conductive member 20 to reduce the area of ​​the first conductive member 10 and / or the second conductive member 20 in the radial cross section.

[0059] Understandably, in order to achieve sensitive detection of cell expansion and ensure timely interruption of electrical signal transmission when a preset threshold is reached, at least one groove structure can be provided on the first conductive element 10 and / or the second conductive element 20.

[0060] The groove structure improves the response sensitivity to changes in cell expansion by reducing the effective cross-sectional area of ​​the first conductive element 10 and / or the second conductive element 20 at specific locations, making these locations potential breakage points.

[0061] The groove structure is used to reduce the effective cross-sectional area of ​​the material in the thickness direction, thereby reducing the structural strength at that location and making it more prone to fracture under external forces (such as stress caused by the expansion of the battery cell).

[0062] The groove structure is set on the radial section of the first conductive element 10 and / or the second conductive material. It can be understood that the groove structure is located on the side of the material and extends along the thickness direction, but does not penetrate the material. It only makes a certain reduction in the structure, so as to ensure that there is a sufficient conductive path and provide a potential break point, which has already broken under certain conditions.

[0063] The groove structure can be rectangular, V-shaped, or U-shaped, etc. Different shapes will affect its fracture characteristics and the required fracture force, and the choice can be made according to the actual situation. Deeper or longer grooves will significantly reduce the strength of the material, making it easier to fracture and making the detection device more sensitive, while shallower or shorter grooves may only weaken the local strength and are suitable for higher threshold requirements.

[0064] For example, in one embodiment, based on the principle of thermal expansion, copper can be used as the first conductive element 10 (which has a high coefficient of thermal expansion), and nickel can be used as the second conductive element 20. V-shaped grooves are formed on the surface of the first conductive element 10. As the temperature rises, the expansion of copper will cause additional stress concentration at these grooves. Once the ultimate tensile strength of the material is exceeded, the grooves will break, thereby interrupting the electrical signal.

[0065] In another embodiment, based on the pressure sensing principle, a nickel-titanium alloy can be used as the first conductive element 10, and the groove structure is set on the first conductive element 10. When the internal pressure of the battery casing increases to a certain extent, the groove structure will break first because it cannot withstand the pressure, thereby protecting the entire system from overpressure damage.

[0066] In scenarios where multi-level detection of cell 00 expansion is performed, multiple groove structures can be set on the first conductive element 10 or the second conductive element 20 to achieve phased safety protection.

[0067] For example, in one embodiment, based on the principle of thermal expansion, the first conductive element 10 can be copper, with a coefficient of thermal expansion of approximately 16.5 × 10⁻⁶ / ℃, and the second conductive element 20 can be nickel, with a coefficient of thermal expansion of approximately 13.0 × 10⁻⁶ / ℃.

[0068] Multiple V-shaped grooves are provided along the length of the copper (first conductive element 10), and these grooves are arranged from shallow to deep in terms of depth and width.

[0069] For example, the grooves near the center of cell 00 are shallower, with a depth of 10% of the material thickness; the grooves in the middle part are 20% of the material thickness; and the grooves further away from the center of cell 00 are 30% of the material thickness.

[0070] When cell 00 expands due to charge / discharge cycles or temperature rise, copper material will be preferentially affected by stress due to its high coefficient of thermal expansion. Since the expansion trend is different at different locations of cell 00, as the degree of expansion gradually increases, the breakage of any one of the multiple groove structures can interrupt the electrical signal transmission of the thermocouple and activate protective measures such as risk warnings.

[0071] In another embodiment, multiple groove structures can be disposed on a conductive material with a low coefficient of thermal expansion. For example, the first conductive element 10 can be aluminum with a coefficient of thermal expansion of approximately 23.0 × 10⁻⁶ / ℃, and the second conductive element 20 can be stainless steel with a coefficient of thermal expansion of approximately 17.3 × 10⁻⁶ / ℃.

[0072] More grooves or notches are made in stainless steel (a material with a low coefficient of thermal expansion) to reduce its mechanical strength, making it more prone to breakage when the cell expands.

[0073] The stainless steel surface has multiple U-shaped grooves, with more groove structures than those on aluminum materials. The groove depth is 20%-30% of the thickness of the stainless steel material, and deeper grooves are set in key areas (such as near the edge of the battery cell).

[0074] Although stainless steel has a lower coefficient of thermal expansion than aluminum, it is more prone to fracture during cell expansion due to the presence of more grooves.

[0075] When the cell expands to a certain threshold, the groove on the stainless steel will fail first, interrupting the electrical signal transmission of the thermocouple and thus triggering the safety mechanism.

[0076] If the expansion continues to intensify, the grooves on the aluminum material will also break, further enhancing safety protection.

[0077] By setting multiple groove structures on a conductive material with a small coefficient of thermal expansion, the detection device can be adapted to scenarios that require balancing the properties of different materials.

[0078] For example, in energy storage systems operating at high temperatures, aluminum is prone to significant deformation due to its high coefficient of thermal expansion, while stainless steel is relatively stable. By incorporating more grooves into the stainless steel, the fracture behavior of the two materials can be made more coordinated, avoiding false alarms or missed alarms caused by premature failure of a single material.

[0079] In some embodiments,

[0080] In some embodiments, such as Figure 3-5 As shown, there are multiple sets of first conductive element 10 and / or second conductive element 20, which are spaced apart; and / or, both the first conductive element 10 and the second conductive element 20 are provided with multiple groove structures; and / or, the number of groove structures provided on the first conductive element 10 is different from the number of groove structures provided on the second conductive element 20.

[0081] Understandably, to further improve the sensitivity, reliability, and safety of the detection device, a design with multiple sets of first conductive elements 10 and / or second conductive elements 20, spaced apart, can be adopted. This enables distributed monitoring of the cell's 00 status, while providing redundant protection through multiple independent thermocouple units to improve the overall system performance.

[0082] The multiple sets of conductive materials spaced apart can cover a larger surface area of ​​the battery cell, enabling comprehensive monitoring of cell expansion, temperature changes, or stress distribution. Each set of conductive materials can operate independently, forming multiple thermocouple units, each corresponding to a different monitoring point.

[0083] If one group of conductive materials fails unexpectedly, the other groups can still function normally, thus avoiding the risk of a single point of failure causing the entire system to fail.

[0084] Different groups of conductive materials can be set with different trigger thresholds according to their location and design characteristics (such as groove depth, material thickness, etc.) to achieve a phased safety response. Through the coordinated work of multiple groups of conductive materials, even if some conductive materials fail to break in time, other groups can still ensure the triggering of the safety mechanism.

[0085] Multiple sets of conductive materials are evenly distributed on the surface of the cell 00 to ensure that each area can be effectively monitored. In areas of the cell 00 that are prone to expansion or overheating (such as the edge or center), the number or density of conductive material sets is increased to improve monitoring accuracy.

[0086] Each group of conductive materials can be independently connected to the signal processing circuit, forming multiple independent thermocouple units. Alternatively, multiple groups of conductive materials can be connected in series or parallel to form a unified circuit for comprehensive monitoring.

[0087] Target structures 30 (such as grooves, weak points, or other mechanically sensitive structures) are set on each group of conductive materials to ensure that fracture occurs under specific conditions. The target structures 30 of different groups can be adjusted according to their position and function.

[0088] For example, the group near the center of cell 00 can have shallower grooves to preferentially respond to smaller expansions; the group near the edge of cell 00 can have deeper grooves to cope with more severe expansions or stresses. To cover all critical areas of the cell surface and enable timely detection of local anomalies, distributed monitoring of the cell surface can be achieved by designing multiple groups of the first and / or second conductive elements and spacing them apart, ensuring that the state of each area can be effectively monitored.

[0089] like Figure 3 As shown, there are three sets of first conductive elements 10 and three sets of second conductive elements 20, which are evenly distributed on the surface of the battery cell.

[0090] Each group of first conductive elements and corresponding second conductive elements forms an independent thermocouple unit, used to monitor the temperature or expansion state of a specific area.

[0091] Multiple sets of conductive elements can cover a larger cell surface area, ensuring comprehensive perception of the overall cell status. Even if one set of conductive elements fails, the others can still function normally, avoiding the risk of a single point of failure. In critical areas where the cell is prone to expansion or overheating (such as edges or centers), the number or density of conductive element sets can be increased to improve monitoring accuracy.

[0092] Multiple groove structures can also be provided on both the first conductive element 10 and the second conductive element 20. The groove structure can reduce the mechanical strength of the material at a specific location, making it more likely to break when subjected to stress or expansion, thereby triggering a safety mechanism.

[0093] By providing multiple groove structures on both the first conductive element 10 and the second conductive element 20, the sensitivity and reliability of the detection device can be further enhanced.

[0094] The groove structure can be V-shaped, U-shaped, or other shapes, with its depth, width, and distribution adjusted according to specific needs. Different groove shapes affect the ease of fracture. For example, V-shaped grooves are more likely to fracture under lower stress than rectangular grooves. The grooves can be arranged linearly along the length of the conductive component or form a grid-like layout along the width.

[0095] Deeper or denser grooves can be formed in critical areas of the battery cell (such as cell edges or solder joints) to prioritize the monitoring of abnormalities in these areas. The number of grooves on the first conductive element 10 and the second conductive element 20 can also differ.

[0096] Due to the different material properties (such as coefficient of thermal expansion, elastic modulus, etc.) of the first conductive element 10 and the second conductive element 20, the fracture sensitivity of the conductive element can be balanced by using different numbers of grooves.

[0097] By adjusting the number of grooves, both can work together under the same conditions, preventing a conductive component 10 from breaking too early or too late.

[0098] With a greater number of grooves on the first conductive element 10, the coefficient of thermal expansion of the first conductive element 10 is larger (e.g., aluminum or copper), making it more prone to deformation under the same conditions. Therefore, more grooves can be provided on the first conductive element to reduce its fracture threshold and keep it synchronized with the second conductive element.

[0099] By reducing the number of grooves on the second conductive element 20, and if the coefficient of thermal expansion of the second conductive element 20 is low (such as stainless steel or tungsten), deformation will be smaller under the same conditions. Therefore, fewer grooves can be provided on the second conductive element to compensate for its lower expansion characteristics, ensuring that it can break in time when necessary.

[0100] In battery systems operating at high temperatures, the first conductive element 10 may deform preferentially due to its higher coefficient of thermal expansion, thus requiring more grooves to balance the behavior of the two materials.

[0101] For example, in the case of combining multiple sets of conductive elements with the groove structure, three sets of first conductive elements 10 (copper) and three sets of second conductive elements 20 (nickel) are arranged on the surface of the cell 00, with each set spaced 5 cm apart.

[0102] Multiple V-shaped grooves are provided on each group of conductive components. The first conductive component 10 has a larger number of grooves (e.g., 6 per group), while the second conductive component 20 has a smaller number of grooves (e.g., 3 per group).

[0103] When the battery cell 00 expands due to charge-discharge cycles or temperature rise, the groove on the first conductive element 10 will first break due to stress concentration, interrupting the transmission of electrical signals.

[0104] With a focus on monitoring edge expansion of the battery cell, three sets of first conductive elements 10 (aluminum) and three sets of second conductive elements 20 (stainless steel) are arranged in the edge region of the battery cell 00, with more and deeper grooves on the first conductive elements 10. Each set of the first conductive elements 10 in the edge region has eight grooves, while each set of the second conductive elements 20 has four grooves. When the edge of the battery cell begins to expand, the grooves on the first conductive elements 10 break first, issuing a warning signal.

[0105] If the expansion spreads throughout the entire cell, the groove on the second conductive element 20 will also break, triggering full protection.

[0106] In some embodiments, such as Figure 4 As shown, there are multiple sets of first conductive elements 10 and one set of second conductive elements 20. The target structure 30 is disposed on the first conductive elements 10. The coefficient of thermal expansion of the first conductive elements 10 is smaller than that of the second conductive elements 20.

[0107] Understandably, the first conductive element 10 is selected from materials with a low coefficient of thermal expansion, such as stainless steel, tungsten, or nickel-silicon alloys. These materials exhibit minimal dimensional changes with temperature variations, thus serving as relatively stable reference points.

[0108] The second conductive element 20 can be made of a material with a high coefficient of thermal expansion, such as copper, aluminum, or nickel-chromium alloy. Such materials undergo greater dimensional changes compared to the first conductive element 10 when the temperature changes, which helps to generate a significant thermoelectric electromotive force, thereby improving the sensitivity of temperature detection.

[0109] The target structure 30 is disposed on each group of first conductive elements 10. The target structure 30 may be a groove, a weak point, etc. It is used to make the first conductive elements 10 more likely to break at these locations when the cell 00 expands or is subjected to other stresses.

[0110] Because the first conductive element 10 and the second conductive element 20 have different coefficients of thermal expansion, their lengths change at different rates when the temperature of the battery cell 00 changes, resulting in a thermoelectric electromotive force at the contact point. This voltage signal can be used to monitor the temperature change of the battery cell 00. As the battery cell 00 expands or is subjected to different stresses, the target structure 30 on the first conductive element 10 will experience additional stress. Because the first conductive element 10 has a lower coefficient of thermal expansion, it is less likely to deform with the expansion of the battery cell 00 under the same conditions than the second conductive element 20, thus stress concentration is more likely to form at the target structure 30. Once the stress exceeds the ultimate strength of the material, the target structure 30 will fracture, thereby interrupting the transmission of the electrical signal.

[0111] Using multiple sets of first conductive elements 10 means there are multiple potential breakpoints, increasing the redundancy of the system. Even if one set fails to respond in time, the other sets can still ensure the effective triggering of the safety mechanism.

[0112] For example, safety devices based on temperature monitoring;

[0113] The first conductive component 10 can be made of stainless steel, with a coefficient of thermal expansion of approximately 17.3 × 10⁻⁶ / ℃;

[0114] The second conductive element 20 can be made of copper, with a coefficient of thermal expansion of approximately 16.5 × 10⁻⁶ / ℃;

[0115] A series of V-shaped grooves, with a depth of 20% of the material thickness, are set on each group of stainless steel materials.

[0116] During the operation of cell 00, as the temperature of cell 00 rises, the copper material expands faster than the stainless steel material, resulting in a thermoelectric electromotive force between the two. If the temperature continues to rise to a dangerous level, the V-shaped groove on the stainless steel will first break due to stress concentration, interrupting the transmission of electrical signals and triggering safety measures.

[0117] Therefore, this detection device can not only effectively monitor the state changes of the cell 00, but also take swift action when necessary to ensure the safety of the battery system.

[0118] In some embodiments, such as Figure 5 As shown, there are multiple sets of second conductive elements 20 and one set of first conductive elements 10. The target structure 30 is disposed on the second conductive elements 20. The expansion coefficient of the second conductive elements 20 is smaller than that of the first conductive elements 10.

[0119] The difference between this embodiment and the previous embodiment is only that the second conductive element 20 is set as multiple groups, and the target structure 30 is set on them, and the expansion coefficient of the second conductive element 20 is made smaller than the expansion coefficient of the first conductive element 10. This is only carried out as another embodiment, for example, a safety device based on temperature monitoring.

[0120] The first conductive element 10 can be made of copper, with a coefficient of thermal expansion of approximately 16.5 × 10⁻⁶ / ℃;

[0121] The second conductive component 20 can be made of stainless steel, with a coefficient of thermal expansion of approximately 17.3 × 10⁻⁶ / ℃;

[0122] A series of V-shaped grooves, with a depth of 20% of the material thickness, are set on each group of stainless steel materials.

[0123] During the operation of cell 00, as the temperature rises, the copper material expands faster than the stainless steel material, resulting in a thermoelectric electromotive force between them. If the temperature continues to rise to a dangerous level, the V-shaped groove on the stainless steel will break first due to stress concentration, interrupting the transmission of electrical signals and triggering safety measures. This detection device can not only effectively monitor changes in the state of cell 00, but also take swift action when necessary to ensure the safety of the battery system.

[0124] In some embodiments, such as Figure 3 As shown, there are multiple sets of the first conductive element 10 and the second conductive element 20, which are connected to each other respectively. The target structure 30 is disposed on the conductive material with the smaller coefficient of expansion among the first conductive element 10 and the second conductive element 20.

[0125] Understandably, the first conductive element 10 and the second conductive element 20 are both multiple sets, and they are respectively connected to form multiple independently working thermocouple units. The target structure 30 is set on a conductive material with a small coefficient of expansion, which can preferentially trigger the fracture mechanism under specific conditions, thereby interrupting the transmission of electrical signals and activating safety protection measures.

[0126] Multiple sets of conductive materials are spaced apart, which can cover a larger surface area of ​​the battery cell, enabling comprehensive monitoring of battery cell expansion, temperature changes, or stress distribution.

[0127] Each group of conductive materials can work independently, forming multiple thermocouple units, each corresponding to a different monitoring point.

[0128] Each group of conductive materials forms an independent thermocouple unit, which monitors the cell status (such as temperature, expansion, or pressure) of the area it covers in real time.

[0129] When the state of a certain area exceeds a preset threshold, the target structure 30 on the conductive material of that group will break, interrupting the electrical signal transmission of that group.

[0130] If multiple areas experience anomalies simultaneously (such as overall expansion of cell 00 or large-area overheating), multiple sets of conductive materials will respond in concert, triggering a higher level of safety mechanisms.

[0131] For example, in electric vehicles or energy storage systems, battery packs typically consist of multiple individual cells with a large surface area. By arranging multiple sets of conductive materials on the surface of the cells, distributed monitoring of the entire battery pack can be achieved, allowing for the timely detection of local anomalies (such as overheating or expansion of a particular cell).

[0132] The redundant design using multiple sets of conductive materials ensures that the system continues to function normally even if some monitoring units fail. This makes it suitable for scenarios with extremely high safety requirements (such as battery systems in aerospace or medical devices).

[0133] Alternatively, three sets of conductive materials can be arranged in the edge region of the cell, while only one set of conductive materials can be arranged in the center region. Deeper grooves are set on the conductive materials in the edge region to prioritize the monitoring of edge expansion.

[0134] When the edge of the battery cell begins to expand, the conductive material in the edge area breaks first, issuing a warning signal; if the expansion spreads to the center area, the conductive material in the center area will also break, activating full protection.

[0135] In some embodiments, the first conductive element 10 and the second conductive element 20 are flat.

[0136] Understandably, the flat shape of the first conductive element 10 and the second conductive element 20 increases the contact area with the surface of the battery cell 00, thereby more effectively transferring heat or changes in mechanical stress, and thus improving the performance of the detection device. In addition, the flat shape also helps to reduce material usage, lower manufacturing costs, and simplify the installation process.

[0137] The flat shape increases the contact area between the conductive material and the surface of the battery cell, improving heat conduction efficiency. This allows temperature changes to be detected more quickly, enhancing the response speed of the detection device.

[0138] The flat structural features also help disperse the stress applied to the material, avoiding premature failure caused by localized stress concentration. Furthermore, flat conductive materials are easier to adhere to the cell surface, facilitating integration into existing battery management systems. In addition, they occupy less space and do not significantly increase the overall size of the battery pack.

[0139] Setting target structures 30 (such as grooves, notches, etc.) on flat materials offers greater flexibility. The position, depth, and width of the grooves can be adjusted according to specific needs to achieve different fracture thresholds or response characteristics.

[0140] In the second aspect, such as Figure 1-5 As shown, this disclosure proposes a lithium battery, including a cell 00 and a detection device; the detection device includes a first conductive element 10, the first conductive element 10 having a first expansion coefficient; a second conductive element 20, the second conductive element 20 having a second expansion coefficient different from the first conductive element 10, and the first conductive element 10 and the second conductive element 20 are connected to form a thermocouple, the thermocouple being disposed on the surface of the cell 00 for detecting the temperature of the cell 00.

[0141] The target structure 30 is disposed on the first conductive element 10 and / or the second conductive element 20. The target structure 30 enables the first conductive element 10 or the second conductive element 20 to break when the cell 00 expands to the target threshold, thereby interrupting the electrical signal transmission of the thermocouple.

[0142] Understandably, the lithium battery proposed in this disclosure not only possesses basic energy storage capabilities but also integrates a detection device for monitoring the temperature and expansion state of the cell 00. This detection device operates on the principle of thermocouples and can automatically interrupt electrical signal transmission when severe expansion of the cell 00 is detected, thereby protecting the safety of the entire battery or battery pack.

[0143] As the core component of lithium batteries, cell 00 is responsible for storing and releasing energy. Two conductive materials with different expansion coefficients are connected to form a thermocouple, which is installed on the surface of cell 00 to monitor the temperature of cell 00 in real time.

[0144] Because the first conductive element 10 and the second conductive element 20 have different coefficients of thermal expansion, these two materials will undergo different degrees of dimensional changes when the temperature changes, resulting in a thermoelectric electromotive force at the contact point. This voltage signal can be used to monitor the temperature change of the battery cell 00.

[0145] To improve the sensitivity to the expansion state of the battery cell 00, a target structure 30 (such as a groove, weak point, etc.) is provided on the first conductive element 10 and / or the second conductive element 20. The target structure 30 enables the battery cell 00 to break preferentially at these locations when it expands to a certain preset threshold, thereby interrupting the electrical signal transmission of the thermocouple.

[0146] The location where cell 00 may expand is set as the target location. The target location can be based on areas prone to expansion determined by past experience or theoretical analysis. This may include the edges of cell 00, solder joints, or other stress concentration areas.

[0147] To effectively protect these easily expandable areas from expansion, the target structure 30 in the detection device is aligned with the target location of the battery cell 00. This ensures that if the battery cell 00 expands in these specific areas, the target structure 30 will be affected first, thereby triggering the safety mechanism.

[0148] For example, the first conductive element 10 can be a nickel-chromium alloy.

[0149] The second conductive element 20 can be a nickel-silicon alloy, and the second conductive element 20 has a lower coefficient of thermal expansion than the first conductive element 10.

[0150] A series of V-shaped grooves are provided on the second conductive element 20 (nickel-silicon alloy) near the edge of the cell 00, with a depth of 20%-30% of the material thickness.

[0151] When the edge area of ​​the battery cell 00 begins to expand due to charge-discharge cycles or other reasons, the V-shaped groove on the nickel-silicon alloy will break first due to stress concentration, interrupting the transmission of electrical signals and triggering corresponding protection measures, such as cutting off the power supply or issuing an alarm.

[0152] In some embodiments, such as Figure 2 As shown, an adhesive layer 40 is provided between the surface of the battery cell 00 and the thermocouple.

[0153] Understandably, in order to ensure the connection between the first conductive element 10 and the second conductive element 20, and to ensure that the formed thermocouple can be firmly attached to the surface of the battery cell 00 and achieve efficient heat conduction, an adhesive layer 40 is provided on the surface of the battery cell 00. The adhesive layer 40 not only serves to fix the thermocouple, but also optimizes heat transfer performance and protects the thermocouple from the influence of the external environment.

[0154] The thickness of the adhesive layer 40 ranges from 0.1 mm to 0.5 mm.

[0155] The adhesive layer 40 can be made of thermally conductive silicone, thermally conductive epoxy resin, or graphene-based thermally conductive coating, giving it high thermal conductivity to ensure that the thermocouple can quickly sense the temperature change on the surface of the battery cell 00.

[0156] It can also be an organic silicone adhesive or a polyurethane adhesive, which can have good adhesion to the surface of the battery cell and thermocouple materials to ensure long-term stability.

[0157] It can also be used as a flexible thermal pad, elastic adhesive, etc., to have flexibility to adapt to the expansion and contraction of the battery cell during charging and discharging.

[0158] The adhesive layer 40 can be applied to the surface of the battery cell 00 by coating, such as spraying, brushing, dispensing, or pasting. It can also be applied by curing; for example, when the adhesive layer 40 is made of thermally conductive epoxy resin, a curing process is required.

[0159] It should be noted that the presence of the adhesive layer 40 does not affect the fracture behavior of the target structure 30 caused by external factors. For example, the thickness of the adhesive layer 40 can be reduced or a flexible material can be used near the target structure 30.

[0160] The adhesive layer 40 fills the tiny gaps between the thermocouple and the surface of the cell 00, reducing thermal resistance and thus improving thermal conductivity. This helps the thermocouple respond more quickly and accurately to changes in the temperature of the cell 00. The adhesive layer 40 also firmly fixes the thermocouple to the surface of the cell 00, preventing displacement or detachment due to vibration, impact, or other external factors, ensuring long-term stable operation of the thermocouple.

[0161] In the production process of battery cell 00, in order to integrate the detection device with the battery cell 00 and achieve accurate temperature monitoring or expansion protection functions, the intermediate connection of the battery cell 00 is broken by laser, and the detection device is connected to the battery cell 00 by hot pressing.

[0162] Understandably, in some applications, the battery cell may have multiple intermediate connections pre-installed (e.g., for testing or other temporary purposes), but in the final product, only one or a few specific connection points need to be retained to install the testing device. By using high-precision laser technology, unwanted intermediate connections can be precisely cut without affecting the connections that need to be retained.

[0163] A uniform adhesive layer 40 (approximately 0.1 mm to 0.5 mm thick) is applied to the surface of the battery cell 00. The detection device (a thermocouple with a target structure 30 formed by connecting a first conductive device and a second conductive device) is placed on the surface of the battery cell 00 and gently pressed to remove air bubbles and initially fix it in place. The adhesion strength between the detection device and the surface of the battery cell 00 is enhanced by hot pressing, and the adhesive layer 40 is cured.

[0164] By using laser to break the intermediate connection line, attaching the detection device, and hot-pressing, the detection device can be effectively integrated into the battery cell. This not only achieves efficient temperature monitoring and expansion protection functions but also ensures long-term stability and reliability. It is suitable for lithium battery applications with extremely high safety and performance requirements, such as electric vehicles and energy storage systems, providing a solid foundation for battery management systems.

[0165] In the third aspect, such as Figure 6 As shown, this disclosure proposes an electronic device including at least one lithium battery;

[0166] The lithium battery includes a cell 00 and a detection device; the detection device includes a first conductive element 10 having a first coefficient of expansion; a second conductive element 20 having a second coefficient of expansion different from that of the first conductive element 10, and the first conductive element 10 and the second conductive element 20 are connected to form a thermocouple, the thermocouple being disposed on the surface of the cell 00 for detecting the temperature of the cell 00.

[0167] The target structure 30 is disposed on the first conductive element 10 and / or the second conductive element 20. The target structure 30 enables the first conductive element 10 or the second conductive element 20 to break when the cell 00 expands to the target threshold, thereby interrupting the electrical signal transmission of the thermocouple.

[0168] Understandably, an electronic device may include a single lithium battery or a battery pack composed of multiple lithium batteries, with each lithium battery having a corresponding detection device. The battery not only has basic energy storage functions but also integrates a detection device for monitoring the temperature and expansion state of the cell 00. The detection device works on the principle of thermocouples and can automatically interrupt the transmission of electrical signals when it detects severe expansion of the cell 00, thereby protecting the safety of the entire battery pack.

[0169] A battery pack can be composed of multiple cells 00. Each cell 00 is equipped with a detection device, and the detection device is connected to the temperature detection circuit on the PCB board 50 to realize real-time monitoring of each cell 00. The battery protection board chip (IC) can read the temperature data of each cell 00 and take corresponding protection measures when an abnormality is detected, such as shutting down the battery pack and recording the fault location.

[0170] The work process is as follows:

[0171] Under normal circumstances, the thermocouple on each cell 00 can accurately transmit temperature signals to the battery protection board chip. By analyzing these signals, the operating status of each cell 00 can be monitored in real time.

[0172] The battery protection board chip continuously reads the temperature data from each cell and displays or records it for subsequent analysis.

[0173] In the event of severe expansion of a certain cell 00, the target structure 30 (e.g., a deep V-shaped notch) on it will break first due to the difference in expansion between materials and the weak connection points of the structure itself.

[0174] Because the second conductive element 20 (assumed to be a nickel-silicon alloy) has a small coefficient of expansion and weak tensile strength at the V-notch, it will break when the expansion reaches its limit. Once the target structure 30 breaks, the electrical signal transmission of the thermocouple will be interrupted, causing the battery protection board chip to be unable to read valid temperature data from the cell 00.

[0175] Defined as an abnormal situation, it triggers the battery protection board chip to perform corresponding protection measures, such as cutting off the power supply, to avoid more serious safety hazards.

[0176] The battery protection board chip can not only identify which cell has malfunctioned, but also record its specific location information.

[0177] like Figure 6 As shown, for example, a battery pack consisting of three cells 00, each cell 00 is equipped with a detection device and is connected to a temperature detection circuit on the same PCB board 50 via leads.

[0178] Under normal operating conditions, the battery protection board chip can reliably read the temperature data of each cell. For example, cells A, B, and C each report their respective temperature values, indicating that they are all within the normal operating range.

[0179] Users can view this temperature data through the interface to ensure that the battery pack is in good condition.

[0180] In the event of expansion, assume that cell 00C begins to expand abnormally. As the expansion intensifies, the deep V-shaped notch on its second conductive element 20 breaks when the expansion reaches a preset threshold due to the low coefficient of expansion and structural weaknesses of the nickel-silicon alloy.

[0181] The breakage caused the thermocouple's electrical signal transmission to be interrupted. The battery protection board chip detected that it could not obtain a valid temperature reading from the cell's 00C and immediately identified this as an abnormal condition.

[0182] Subsequently, the battery protection board chip takes action, which may include cutting off the power supply to the entire battery pack to prevent further damage, and recording the location information of cell 00C as the source of the fault, so that subsequent maintenance personnel can inspect and repair it.

[0183] The leads provide a physical electrical connection path, enabling the thermocouple to be connected to a wider range of circuit systems, such as the temperature detection circuit on the PCB board 50, allowing the thermocouple to monitor the temperature of each cell 00 in real time.

[0184] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0185] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner.

Claims

1. A detection device, characterized in that, include: A first conductive element, wherein the first conductive element has a first coefficient of thermal expansion; The second conductive element has a second coefficient of thermal expansion different from that of the first conductive element, and the first conductive element and the second conductive element are connected to form a thermocouple. The thermocouple is disposed on the surface of the battery cell for detecting the temperature of the battery cell. A target structure is disposed on the first conductive element and / or the second conductive element, the target structure being capable of causing the first conductive element or the second conductive element to break when the battery cell expands to a target threshold, thereby interrupting the electrical signal transmission of the thermocouple.

2. The detection device according to claim 1, characterized in that, The target structure includes at least one groove structure disposed on the first conductive element and / or the second conductive element. The groove structure is disposed in the thickness direction of the first conductive element and / or the second conductive element to reduce the area of ​​the first conductive element and / or the second conductive element in the radial cross section.

3. The detection device according to claim 2, characterized in that, The first conductive element and / or the second conductive element are in multiple groups and are arranged at intervals; And / or, Both the first conductive element and the second conductive element are provided with multiple groove structures; And / or, The number of groove structures provided on the first conductive element is different from the number of groove structures provided on the second conductive element.

4. The detection device according to claim 3, characterized in that, The first conductive element is in multiple groups, the second conductive element is in one group, the target structure is disposed on the first conductive element, and the expansion coefficient of the first conductive element is smaller than the expansion coefficient of the second conductive element.

5. The detection device according to claim 3, characterized in that, The second conductive element is in multiple groups, and the first conductive element is in one group. The target structure is disposed on the second conductive element, and the expansion coefficient of the second conductive element is smaller than that of the first conductive element.

6. The detection device according to claim 3, characterized in that, Both the first conductive element and the second conductive element are multiple sets, and are connected accordingly. The target structure is disposed on the conductive material with the smaller coefficient of thermal expansion among the first conductive element and the second conductive element.

7. The detection device according to claim 1, characterized in that, The first conductive element and the second conductive element are flat.

8. A lithium battery, characterized in that, This includes battery cells and testing equipment; The detection device includes a first conductive element having a first coefficient of thermal expansion; a second conductive element having a second coefficient of thermal expansion different from that of the first conductive element, and the first conductive element and the second conductive element are connected to form a thermocouple, the thermocouple being disposed on the surface of the battery cell for detecting the temperature of the battery cell; A target structure is disposed on the first conductive element and / or the second conductive element, the target structure being capable of causing the first conductive element or the second conductive element to break when the battery cell expands to a target threshold, thereby interrupting the electrical signal transmission of the thermocouple.

9. The lithium battery according to claim 8, characterized in that, An adhesive layer is provided between the surface of the battery cell and the thermocouple.

10. An electronic device, characterized in that, Including lithium batteries; The lithium battery includes a cell and a detection device; the detection device includes a first conductive element having a first coefficient of expansion; a second conductive element having a second coefficient of expansion different from that of the first conductive element, and the first conductive element and the second conductive element are connected to form a thermocouple, the thermocouple being disposed on the surface of the cell for detecting the temperature of the cell; A target structure is disposed on the first conductive element and / or the second conductive element, the target structure being capable of causing the first conductive element or the second conductive element to break when the battery cell expands to a target threshold, thereby interrupting the electrical signal transmission of the thermocouple.

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