Detection element, battery pack, detection method of battery pack and electric equipment

Abstract

The invention discloses a detection element, a battery pack, a detection method of the battery pack and electric equipment, and the detection element comprises a liquid absorption expansion structure which is suitable for being expanded after absorbing liquid; the pressure-sensitive structure is arranged on one side of the imbibition expansion structure, and the pressure-sensitive structure is suitable for detecting the pressure of the imbibition expansion structure on one side and the pressure of the imbibition expansion structure on the other side. Therefore, by arranging the detection element, the leaked liquid can be absorbed, so that the capability of preventing the leaked liquid from flowing is realized, pressure detection can be performed on the two sides of the detection element at the same time, the effects of detecting the leaked liquid and bumping are considered, and the multifunctionality of the detection element is further improved.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a detection element, a battery pack, a battery pack detection method and an electrical device. Background Art

[0002] With the introduction and implementation of the national "dual carbon" strategy, a green, digital, and intelligent ecological energy technology reconstruction has been born. As an important part of the green industry, new energy batteries have ushered in huge development opportunities. However, the safety issues of batteries used in electric vehicles that have emerged during the development of the industry have attracted widespread public attention. Among them, bumps and leakage are the most common safety issues of batteries.

[0003] In the related technology, the monitoring methods for these two problems on the market currently only use single-function devices for independent detection, and the design does not take into account the hazards of electrolyte flow and does not have the ability to resist leakage and flow. Summary of the invention The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one object of the present invention is to provide a detection element, which can absorb the leaked liquid and can also perform pressure detection on both sides of the detection element at the same time.

[0004] The present invention further provides a battery pack.

[0005] The present invention further proposes a battery pack detection method.

[0006] The present invention further provides an electrical device.

[0007] The detection element according to the first aspect of the present invention includes: a liquid absorption and expansion structure, which is suitable for expanding after absorbing liquid; and a pressure-sensitive structure, which is arranged on one side of the liquid absorption and expansion structure, and is suitable for detecting the pressure of the liquid absorption and expansion structure from one side and the pressure from the other side.

[0008] Therefore, by setting up the detection element, it can absorb the leaked liquid, thereby achieving the ability to resist the flow of leaked liquid, and can also perform pressure detection on both sides of the detection element at the same time, thereby taking into account the effects of detecting leakage and bumps, thereby improving the versatility of the detection element.

[0009] In some examples of the present invention, the pressure-sensitive structure includes: a first pressure-sensitive layer, which is arranged on one side of the liquid-absorbing expansion structure, and the first pressure-sensitive layer is suitable for detecting pressure from the liquid-absorbing expansion structure; a second pressure-sensitive layer, which is arranged on a side of the first pressure-sensitive layer away from the liquid-absorbing expansion structure, and the second pressure-sensitive layer is suitable for detecting pressure from a side away from the first pressure-sensitive layer.

[0010] In some examples of the present invention, the response signals of the first pressure-sensitive layer and the second pressure-sensitive layer are different; and / or the response times of the first pressure-sensitive layer and the second pressure-sensitive layer are different.

[0011] In some examples of the present invention, the pressure-sensitive structure further includes: a buffer layer, which is respectively connected to the first pressure-sensitive layer and the second pressure-sensitive layer and is located between the first pressure-sensitive layer and the second pressure-sensitive layer, and the buffer layer is adapted to elastically deform under an external force.

[0012] In some examples of the present invention, the detection element further includes: a housing, the housing is formed with a receiving cavity, the liquid absorption and expansion structure is disposed at one end of the housing, the liquid absorption and expansion structure is at least partially disposed in the receiving cavity, the first pressure-sensitive layer, the buffer layer and the second pressure-sensitive layer are disposed in the receiving cavity, and the second pressure-sensitive layer is disposed at the other end of the housing.

[0013] In some examples of the present invention, the liquid absorption and expansion structure and the second pressure-sensitive layer are connected to the inner wall of the receiving cavity in the circumferential direction, and the first pressure-sensitive layer and the buffer layer are spaced apart from the inner wall of the receiving cavity.

[0014] In some examples of the present invention, the liquid absorption and expansion structure includes: a gel layer, the pressure-sensitive structure is disposed on one side of the gel layer; a capillary pore layer, the capillary pore layer is disposed on the other side of the gel layer, the capillary pore layer is provided with a plurality of capillary pores, and the plurality of capillary pores extend along the thickness direction of the capillary pore layer, and the capillary pores are adapted to rapidly absorb liquid by capillary action and guide the liquid to flow to the gel layer.

[0015] In some examples of the present invention, the thickness of the capillary pore layer is H1, and H1 satisfies the relation: 1.5 mm ≤ H1 ≤ 3 mm; and / or the thickness of the gel layer is H2, and H2 satisfies the relation: 0.1 mm ≤ H2 ≤ 1 mm.

[0016] In some examples of the present invention, the diameter of the capillary pore is d, and d satisfies the relation: 0.1 μm ≤ d ≤ 5 μm; and / or the porosity of the capillary pore is a, and a satisfies the relation: 30% ≤ a ≤ 70%.

[0017] In some examples of the present invention, the crosslinking degree of the gel layer is b, and b satisfies the relation: b ≤ 2%; and / or the porosity of the gel layer is c, and c satisfies the relation: 30% ≤ c.

[0018] The battery pack according to the second aspect of the present invention includes: a tray; a battery cell, the battery cell being disposed above the tray; the above-mentioned detection element, the detection element being disposed between the battery cell and the tray, and the liquid absorption and expansion structure being located between the battery cell and the pressure-sensitive structure.

[0019] In some examples of the present invention, the number of the battery cells is plural, the number of the detection elements is plural, and the plural detection elements are distributed in a matrix manner on the tray, and each detection element corresponds to at least one battery cell.

[0020] In some examples of the present invention, the battery pack further includes: a controller, the controller being electrically connected to the plural pressure-sensitive structures respectively, and the controller being configured to issue different alarm types according to different response signals of the plural pressure-sensitive structures.

[0021] In some examples of the present invention, the detection element is disposed between the top surface of the tray and the bottom surface of the battery cell.

[0022] In some examples of the present invention, an installation groove is provided at the top of the tray, and the detection element is disposed in the installation groove.

[0023] The detection method of the battery pack according to the third aspect of the present invention includes the following steps: obtaining the response signal of the pressure-sensitive structure; issuing a corresponding alarm type according to the response signal of the pressure-sensitive structure.

[0024] In some examples of the present invention, the step of issuing a corresponding alarm type according to the response signal of the pressure-sensitive structure includes: analyzing the numerical level of the response signal of the pressure-sensitive structure; when the numerical level of the pressure-sensitive information reaches a specified threshold, judging the problem type of the battery pack; issuing a corresponding alarm type according to the problem type of the battery pack.

[0025] In some examples of the present invention, the pressure-sensitive structures are plural, and the response signals of the pressure-sensitive structures include the piezoelectric or piezoresistive signal response thresholds of the pressure-sensitive structures and the position numbers of the pressure-sensitive structures; the step of issuing a corresponding alarm type according to the response signals of the pressure-sensitive structures includes: issuing an alarm type corresponding to the position number.

[0026] The electrical equipment according to the fourth aspect of the present invention includes: the above-mentioned battery pack.

[0027] The additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0028] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, in which: Figure 1 is a schematic diagram of a detection element, a tray, and an electric core according to an embodiment of the present invention; Figure 2 is a schematic diagram of a detection element, a tray, and an electric core according to another embodiment of the present invention; Figure 3 is a schematic diagram of a detection component in a state where a battery pack leaks liquid according to an embodiment of the present invention; Figure 4 is a schematic structural diagram of a detection element according to an embodiment of the present invention.

[0029] Figure 5 is a control flowchart of a detection method for a battery pack according to an embodiment of the present invention; Figure 6 is a control flowchart of issuing a corresponding alarm type according to an embodiment of the present invention; Figure 7 is a control flowchart of issuing a corresponding alarm type according to another embodiment of the present invention.

[0030] Reference numerals: 100, detection element; 200, battery pack; 201, tray; 2011, installation groove; 202, electric core; 1, liquid absorption and expansion structure; 11, gel layer; 12, capillary pore layer; 2, pressure-sensitive structure; 21, first pressure-sensitive layer; 22, second pressure-sensitive layer; 23, buffer layer; 3, housing; 31, accommodation cavity. Detailed implementation manners

[0031] The embodiments of the present invention will be described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention will be described in detail below.

[0032] Below, reference is made to Figures 1 - 7 to describe the transmission mechanism of the steering device according to an embodiment of the present invention, which can absorb liquid leakage and can also detect the pressure on both sides of the detection element 100 at the same time.

[0033] In combination with Figures 1 - 4 as shown, the detection element 100 according to the first aspect of the present invention includes a liquid absorption and expansion structure 1 and a pressure-sensitive structure 2. Among them, the liquid absorption and expansion structure 1 can adsorb flowing liquid and expand in volume, and the pressure-sensitive structure 2 can sensitively sense the magnitude of the externally transmitted pressure.

[0034] Specifically, the liquid-absorbing swelling structure 1 is suitable for swelling after absorbing liquid, and the pressure-sensitive structure 2 is arranged on one side of the liquid-absorbing swelling structure 1. The pressure-sensitive structure 2 is suitable for detecting the pressure from one side of the liquid-absorbing swelling structure 1 and the pressure on the other side.

[0035] For example, when the liquid-absorbing expansion structure 1 absorbs the flowing liquid and becomes expanded, the liquid-absorbing expansion structure 1, on the one hand, absorbs and contracts the liquid, thereby achieving the ability to resist the flow of the liquid, and on the other hand, converts the liquid into mechanical force to drive part of the liquid-absorbing expansion mechanism to move toward the side close to the pressure-sensitive structure 2. Since the pressure-sensitive structure 2 has pressure-sensitive properties such as piezoelectricity or piezoresistiveness, when the pressure-sensitive structure 2 is subjected to mechanical force, the mechanical force is converted into an electrical signal or the resistance of the pressure-sensitive structure 2 changes. The relevant signal can be analyzed by the corresponding controller (such as a risk monitoring module) and after reaching the alarm threshold, an alarm prompt (such as an internal leakage signal) is triggered.

[0036] For example, when the other side of the pressure-sensitive structure 2 can directly sense the impact force transmitted from the outside, when the pressure-sensitive structure 2 is subjected to mechanical force, the mechanical force is converted into an electrical signal or the resistance of the pressure-sensitive structure 2 changes. The relevant signal can be analyzed by the corresponding controller (such as a risk monitoring module) and after reaching the alarm threshold, an alarm prompt (such as an external impact signal) is triggered.

[0037] Optionally, the pressure-sensitive material included in the pressure-sensitive structure 2 can be a piezoelectric material such as silicon dioxide, barium titanate, zinc oxide, polyvinylidene fluoride, etc., or a piezoresistive material such as silicon, germanium, graphene, polypyrrole, etc. The response signal depends on the characteristics of the pressure-sensitive material. The response signal of the piezoelectric material is an electrical signal, and the response signal of the piezoresistive material is a resistance change.

[0038] Compared with the traditional detection element, the detection element 100 in this embodiment converts the flowing liquid into mechanical force by adsorption and expansion, and then combines the leakage and bump detection functions through mechanical force perception, and has the function of suppressing the leakage and flow.

[0039] Therefore, by setting up the detection element 100, it can absorb the leaked liquid, thereby achieving the ability to resist the leakage and flow, and can also perform pressure detection on both sides of the detection element 100 at the same time, so as to take into account the effects of detecting leakage and bumps, thereby improving the versatility of the detection element 100.

[0040] According to some optional embodiments of the present invention, in combination Figure 3 and Figure 4 As shown, the pressure-sensitive structure 2 includes a first pressure-sensitive layer 21 and a second pressure-sensitive layer 22. The first pressure-sensitive layer 21 is arranged on one side of the liquid-absorbent swelling structure 1, and the first pressure-sensitive layer 21 is suitable for detecting the pressure from the liquid-absorbent swelling structure 1. The second pressure-sensitive layer 22 is arranged on the side of the first pressure-sensitive layer 21 away from the liquid-absorbent swelling structure 1, and the second pressure-sensitive layer 22 is suitable for detecting the pressure from the side away from the first pressure-sensitive layer 21.

[0041] Specifically, the first pressure-sensitive layer 21 and the second pressure-sensitive layer 22 are respectively arranged on both sides of the pressure-sensitive structure 2. The first pressure-sensitive layer 21 and the second pressure-sensitive layer 22 can independently detect the pressure values on both sides of the pressure-sensitive structure 2, thereby distinguishing the pressure values on different sides, and further achieving the effect of detecting both leakage (such as the side close to the liquid absorption and expansion structure 1) and bumps (such as the other side away from the liquid absorption and expansion structure 1).

[0042] Optionally, the response signals of the first piezoresistance layer 21 and the second piezoresistance layer 22 are different. Since the response signal depends on the characteristics of the piezoresistance material, the response signal of the piezoelectric material is an electrical signal, and the response signal of the piezoresistive material is a resistance change. For example, the first piezoresistance layer 21 and the second piezoresistance layer 22 can be one piezoelectric material and the other piezoresistive material; the first piezoresistance layer 21 and the second piezoresistance layer 22 can also be the same piezoelectric material or piezoresistive material, but the two piezoresistance layers have different signal response degrees by designing the structure or content.

[0043] Alternatively, the response time of the first pressure-sensitive layer 21 and the second pressure-sensitive layer 22 are different. When the first pressure-sensitive layer 21 or the second pressure-sensitive layer 22 is subjected to mechanical pressure, the two pressure-sensitive layers exhibit different response times, so that it can be clearly distinguished whether the mechanical pressure comes from the inside or outside of the pressure-sensitive structure 2, which is conducive to making corresponding leakage or bump alarm prompts.

[0044] Furthermore, combined with Figure 3 and Figure 4 As shown, the pressure-sensitive structure 2 further includes a buffer layer 23, which is connected to the first pressure-sensitive layer 21 and the second pressure-sensitive layer 22 respectively and is located between the first pressure-sensitive layer 21 and the second pressure-sensitive layer 22, and the buffer layer 23 is suitable for elastic deformation under the action of external force. For example, the buffer layer 23 can be a lightweight porous foam such as polyethylene, polyurethane, etc., but is not limited thereto.

[0045] It is understandable that since the buffer layer 23 is suitable for elastic deformation under the action of external force, this is helpful to alleviate external stress, reduce energy transfer or absorb impact, thereby preventing the risk of damage to the first pressure-sensitive layer 21 and the second pressure-sensitive layer 22 due to excessive force to a certain extent.

[0046] Optionally, taking the leakage of the battery cell 202 as an example, when the liquid-absorbing and swelling structure 1 absorbs electrolyte and expands, the squeezing force exerted on the first pressure-sensitive layer 21 is large, and even the buffer layer 23 is compressed toward the second pressure-sensitive layer 22. The buffer layer 23 can generate more space after compression, which not only allows the liquid-absorbing and swelling structure 1 to absorb more electrolyte, but also prevents the electrolyte from flowing arbitrarily inside the battery, thereby reducing the risk of arcing.

[0047] Alternatively, the connection interfaces between the first pressure-sensitive layer 21, the second pressure-sensitive layer 22, and the buffer layer 23 can be fixed by mutual adhesion.

[0048] Specifically, referring to Figure 3 As shown, the detection element 100 further includes a housing 3. The housing 3 is formed with a receiving cavity 31. The liquid absorption and expansion structure 1 is disposed at one end of the housing 3. The liquid absorption and expansion structure 1 is at least partially disposed in the receiving cavity 31. The first pressure-sensitive layer 21, the buffer layer 23, and the second pressure-sensitive layer 22 are disposed in the receiving cavity 31. The second pressure-sensitive layer 22 is disposed at the other end of the housing 3.

[0049] That is to say, the housing 3 can play a role in supporting and fixing the detection element 100. The housing 3 has relatively high mechanical strength and is not easily deformed, which can protect the internal related structures from damage. The housing 3 is formed with a receiving cavity 31. The liquid absorption and expansion structure 1 and the second pressure-sensitive layer 22 are respectively located at both ends of the receiving cavity 31. The receiving cavity 31 can provide a relatively stable and limited space for the liquid absorption and expansion structure 1 and the pressure-sensitive structure 2, avoiding external interference under normal conditions, so as to ensure the normal operation of the detection work.

[0050] Furthermore, referring to Figure 3 and Figure 4 As shown, the liquid absorption and expansion structure 1 and the second pressure-sensitive layer 22 are connected to the inner wall of the receiving cavity 31 along the circumferential direction, and the first pressure-sensitive layer 21 and the buffer layer 23 are spaced from the inner wall of the receiving cavity 31.

[0051] It can be understood that since the liquid absorption and expansion structure 1 is located at the end of the receiving cavity 31 and is tightly connected to the inner wall of the receiving cavity 31, the risk of pressure detection value variation caused by the movement of the second pressure-sensitive layer 22 can be prevented, thereby ensuring the pressure detection accuracy of the second pressure-sensitive layer 22; the liquid absorption and expansion structure 1 is tightly connected to the other end of the receiving cavity 31, which can ensure the relative space range of the receiving cavity 31. Since the first pressure-sensitive layer 21 and the buffer layer 23 are spaced from the inner wall of the receiving cavity 31, a free movement space can be provided for the first pressure-sensitive layer 21 and the buffer layer 23 between the liquid absorption and expansion structure 1 and the second pressure-sensitive layer 22, so as to reserve more liquid absorption and expansion deformation space for the liquid absorption and expansion structure 1, improve the liquid absorption and anti-flow ability of the liquid absorption and expansion structure 1, and further improve the layout rationality and scientificity.

[0052] According to some alternative embodiments of the present invention, referring to Figure 3 and Figure 4As shown in the figure, the liquid absorption and expansion structure 1 includes a gel layer 11 and a capillary pore layer 12. The pressure-sensitive structure 2 is disposed on one side of the gel layer 11, and the capillary pore layer 12 is disposed on the other side of the gel layer 11. The capillary pore layer 12 is provided with a plurality of capillary pores that extend along the thickness direction of the capillary pore layer 12. The capillary pores are adapted to rapidly absorb liquid by capillary action and guide the liquid to flow toward the gel layer 11.

[0053] Among them, the gel layer 11 is a polymer material that can adsorb organic liquids or water. Its cross-linked network structure can adsorb organic molecules through physical or chemical actions and cause expansion. The type of polymer material depends on the adsorption object. When the adsorption object is an organic liquid such as an electrolyte, the gel layer 11 is composed of a cross-linked polymer such as polyacrylate, polyurethane, or silica gel that can absorb organic liquids; when the adsorption material is an aqueous liquid, the gel layer 11 is composed of hydrophilic cross-linked polymers such as polyacrylic acid, polyvinyl alcohol, cellulose, or polyurethane.

[0054] In addition, the capillary pore layer 12 refers to a material layer containing a large number of micropores. There are a large number of micropores in the capillary pore layer 12, and the capillary pore layer 12 has a very high specific surface area. Thus, it can be more suitably applied to scenarios such as adsorption that require a large contact surface, thereby improving the adsorption efficiency. Moreover, the capillary pore layer 12 also has good permeability, so that liquid can pass through quickly, thereby improving the separation and diversion effect on the liquid. Among them, considering the compressive strength, weight, and fast adsorption and transmission speed of the capillary pore layer 12 comprehensively, the constituent material of the capillary pore layer 12 should have excellent mechanical properties and a low density, and the thickness and capillary pore distribution of the capillary pore layer 12 should be as appropriate as possible.

[0055] For example, the capillary pore layer 12 can be made of high-strength materials such as reinforced composite materials (such as carbon fiber-reinforced polyimide, carbon fiber-reinforced epoxy resin, etc.) and metal materials (such as aluminum alloy, magnesium alloy, etc.). The material density should be between 1 and 8 g / cm3. Due to the mechanical strength of the capillary pore layer 12, the solid weight above the detection element 100 will not cause additional signal interference to the pressure-sensitive structure 2.

[0056] Another example is that when the detection element 100 is applied in the battery pack 200, the gel layer 11 can quickly adsorb and convert the flowing conductive liquid into a semi-solid, reducing or avoiding the liquid flow after leakage and reducing the risk of arcing (liquid conduction is one of the main reasons for battery arcing).

[0057] Specifically, the pressure-sensitive structure 2 and the capillary pore layer 12 are respectively located on both sides of the gel layer 11. Multiple capillary pores on the capillary pore layer 12 can form a wide adsorption contact area with the liquid, thereby improving the adsorption range and adsorption efficiency. The liquid rapidly flows to the gel layer 11 under the capillary action of the capillary pores (Capillary action refers to the phenomenon that a liquid automatically rises or falls in a small pipe or narrow space. This phenomenon is mainly driven by two forces: the surface tension of the liquid and the adhesion of the solid wall to the liquid.). The gel layer 11 forms an adsorption and storage effect on the liquid and then undergoes volume expansion. As the gel layer 11 continuously adsorbs the liquid, the volume of the gel layer 11 expands and deforms under the action of gravity towards the side of the pressure-sensitive structure 2 (or is squeezed towards the side of the pressure-sensitive structure 2 with less restraint). In this way, the liquid can be converted into mechanical force and applied to the surface of the pressure-sensitive structure 2, which is beneficial for the pressure-sensitive structure 2 to accurately detect the pressure change information in real time, and then obtain the liquid leakage situation.

[0058] Furthermore, the thickness of the capillary pore layer 12 is H1, and H1 satisfies the relational expression: 1.5 mm ≤ H1 ≤ 3 mm. Among them, when the thickness of the capillary pores is less than 1.5 mm, there is a risk that the structural strength of the capillary pore layer 12 will be insufficient due to the too small thickness of the capillary pore layer 12; when the thickness of the capillary pores is greater than 3 mm, since the thickness of the capillary pore layer 12 is too large, the flow path of the liquid in the capillary pores is longer and the time spent is longer, which is likely to lead to the risk of untimely liquid leakage detection. Moreover, due to the limited overall integration space of the detection element 100, the excessive occupied space of the capillary pore layer 12 is not conducive to the effect of miniaturized and compact design. In summary, designing the thickness of the capillary pore layer 12 within a reasonable range can, on the basis of ensuring the structural strength, not occupy too much space, thereby improving the layout rationality. For example, the thickness of the capillary pore layer 12 can be 1.5 mm, 2 mm, 3 mm, etc., and is not limited thereto.

[0059] In detail, the thickness of the gel layer 11 is H2, and H2 satisfies the relational expression: 0.1 mm ≤ H2 ≤ 1 mm. Among them, when the thickness of the gel layer 11 is less than 0.1 mm, there is a risk that the adsorption capacity of the gel layer 11 will be insufficient due to the too small thickness of the gel layer 11; when the thickness of the gel layer 11 is greater than 1 mm, there will be a problem of excessive occupied space due to the too large thickness of the gel layer 11. In summary, controlling the thickness of the gel layer 11 within a reasonable range can, on the basis of ensuring the adsorption capacity of the gel layer 11, also avoid the gel layer 11 occupying too much space, thereby being beneficial to improving the practicability. For example, the thickness of the gel layer 11 can be 0.1 mm, 0.2 mm, 0.5 mm, 1 mm, etc., and is not limited thereto.

[0060] Specifically, the diameter of the capillary pores is d, and d satisfies the relationship: 0.1um ≤ d ≤ 5um. Among them, when the diameter of the capillary pores is less than 0.1um, since the diameter of the capillary pores is too small, it will block the smoothness of liquid flow, which will cause the liquid to be unable to quickly divert the liquid to the gel layer 11, resulting in the risk of untimely pressure-sensitive detection results. When the diameter of the capillary pores is greater than 5um, since the diameter of the capillary pores is too large, it will lead to a decrease in structural strength and a reduction in the adsorption surface area (i.e., specific surface area), thus reducing the structural reliability of the capillary pore layer 12 and its ability to adsorb liquids. In summary, controlling the diameter of the capillary pores within a reasonable range can, on the basis of ensuring the structural strength of the capillary pore layer 12, also improve the liquid absorption capacity and liquid flow rate. For example, the diameter of the capillary pores can be 0.1um, 0.5um, 1um, 2um, 5um, etc., not limited to this.

[0061] Furthermore, the porosity of the capillary pores is a, and a satisfies the relationship: 30% ≤ a ≤ 70%. Among them, when the porosity of the capillary pores is less than 30%, since the porosity of the capillary pores is too small, that is, the number of channels in the capillary pores is small, it will increase the resistance of the liquid passing through the capillary pore layer 12, thus reducing the liquid transmission efficiency. When the porosity of the capillary pores is greater than 70%, since the porosity of the capillary pores is too large, it will reduce the support structure strength of the capillary pore layer 12, thus easily leading to the risk of collapse and fracture of the capillary pore layer 12. In summary, controlling the porosity of the capillary pores within a reasonable range can, on the basis of ensuring the structural strength of the capillary pore layer 12, also improve the transmission and flow efficiency of the liquid in the capillary pore layer 12. For example, the porosity of the capillary pores can be 30%, 40%, 55%, 70%, etc., not limited to this.

[0062] Specifically, the crosslinking degree of the gel layer 11 is b, and b satisfies the relationship: b ≤ 2%. The crosslinking degree of the gel layer 11 is small, that is, the gel layer 11 has a low crosslinking density, which can make the polymer chains have greater freedom, thus improving the flexibility and ductility of the gel layer 11. Moreover, fewer crosslinking points also mean that more hydrophilic or lipophilic groups are exposed, which can increase the liquid absorption capacity of the gel layer 11. And there are more open channels, which can improve the penetration rate and diffusion path of the liquid inside the gel layer 11, thus improving the liquid transmission capacity inside the gel layer 11. For example, the crosslinking degree of the gel layer 11 can be 0.5%, 0.8%, 1.5%, 2%, etc., not limited to this.

[0063] Furthermore, the porosity of the gel layer 11 is c, and c satisfies the relation: 30% ≤ c. Herein, the porosity refers to the proportion of the pore volume in the total volume of the material. A larger porosity can provide more space to accommodate liquid, thereby improving the liquid absorption capacity of the gel layer 11. It can also allow the liquid to flow more easily in the gel layer 11, thereby improving the penetration and diffusion efficiency of the liquid within the gel layer 11. For example, the porosity of the gel layer 11 can be 30%, 40%, 55%, 80%, etc., which is not limited thereto.

[0064] Combined with Figures 1 - 4 As shown, the battery pack 200 according to the embodiment of the second aspect of the present invention includes a tray 201, a battery cell 202, and the detection element 100 of the above embodiment. The battery cell 202 is disposed above the tray 201, the detection element 100 is disposed between the battery cell 202 and the tray 201, and the liquid absorption and expansion structure 1 is located between the battery cell 202 and the pressure-sensitive structure 2.

[0065] Specifically, the tray 201 mainly serves to support and protect the battery cell 202. The battery cell 202 is the basic unit of the battery and is mainly used for storing and releasing energy. The detection element 100 is located between the battery cell 202 and the tray 201, and the liquid absorption and expansion structure 1 of the detection element 100 is close to the side of the battery cell 202. When the electrolyte in the battery cell 202 leaks, the liquid absorption and expansion structure 1 can quickly adsorb and store the electrolyte, thereby preventing the risk of electrolyte flowing, and improving the anti-flow ability. Moreover, as the liquid absorption and expansion structure 1 continuously expands and deforms, the liquid absorption and expansion structure 1 converts the liquid into mechanical force acting on the pressure-sensitive structure 2, which is beneficial for the pressure-sensitive structure 2 to detect the pressure change value in real time and issue a leakage prompt for the battery cell 202.

[0066] According to some optional embodiments of the present invention, the number of battery cells 202 is multiple, and the number of detection elements 100 is multiple. The multiple detection elements 100 are distributed in a matrix on the tray 201, and each detection element 100 corresponds to at least one battery cell 202. With the above arrangement, the number of detection elements 100 can be increased, thereby improving the detection accuracy of each battery cell 202 by the detection element 100, and further avoiding the risks of missed detection and false detection of the detection element 100.

[0067] According to some optional embodiments of the present invention, the battery pack 200 further includes a controller. The controller is electrically connected to the multiple pressure-sensitive structures 2 respectively, and the controller is configured to issue different alarm types according to different response signals of the multiple pressure-sensitive structures 2.

[0068] Specifically, the controller is electrically connected to multiple pressure-sensitive structures 2 respectively, which can improve the response speed and accuracy of the detection element 100 during the detection work, thereby improving the sensitivity of the detection element 100. Moreover, the controller can also issue different alarm types (such as liquid leakage alarm, bump alarm, etc., not limited to this) according to different response signals sent by the pressure-sensitive structure 2, thereby improving the intelligence of the detection element 100.

[0069] According to some alternative embodiments of the present invention, in combination with Figure 1 As shown, the detection element 100 is disposed between the top surface of the tray 201 and the bottom surface of the battery cell 202. Among them, since the electrolyte of the battery cell 202 will flow downward under the action of gravity and the capillary force of the capillary pore layer 12 in the detection element 100, such an arrangement is conducive to the detection element 100 to smoothly perform the liquid leakage detection work, thereby improving the layout rationality and detection work reliability of the detection element 100.

[0070] According to some alternative embodiments of the present invention, in combination with Figure 2 As shown, an installation groove 2011 is provided at the top of the tray 201, and the detection element 100 is disposed in the installation groove 2011. Among them, the detection element 100 is disposed in the installation groove 2011 at the top of the tray 201, which can form a more effective structural protection effect on the detection element 100 by the installation groove 2011, and can also prevent the detection element 100 from additionally occupying the overall vertical space of the battery pack 200, thereby improving the space utilization rate.

[0071] In combination with Figures 5 - 7 As shown, the detection method of the battery pack 200 according to the third aspect embodiment of the present invention includes the following steps: obtaining the response signal of the pressure-sensitive structure 2; and issuing a corresponding alarm type according to the response signal of the pressure-sensitive structure 2.

[0072] Specifically, in combination with Figure 5 As shown, after the controller obtains the response signal of the pressure-sensitive structure 2 to the pressure, the controller then issues a signal of a corresponding alarm type according to different response signals of the pressure-sensitive structure 2. For example, when the liquid absorption and expansion structure 1 adsorbs the leaked electrolyte and expands, the liquid absorption and expansion structure 1 applies a force to the pressure-sensitive structure 2. As the pressure received by the pressure-sensitive structure 2 changes, the pressure-sensitive response value of the pressure-sensitive structure 2 changes and transmits its response signal to the controller in real time. The controller then issues a corresponding liquid leakage alarm signal according to the response signal of the pressure-sensitive structure 2. Another example is that when an external pressure is applied to the side of the pressure-sensitive structure 2 away from the battery cell 202, as the pressure received by the pressure-sensitive structure 2 changes, the pressure-sensitive response value of the pressure-sensitive structure 2 changes and transmits its response signal to the controller in real time. The controller then issues a corresponding external bump alarm signal according to the response signal of the pressure-sensitive structure 2.

[0073] According to some alternative embodiments of the present invention, in combination with Figure 6 As shown, the steps of issuing a corresponding alarm type according to the response signal of the pressure-sensitive structure 2 include: analyzing the numerical level of the response signal of the pressure-sensitive structure 2; when the numerical level of the pressure-sensitive information reaches a specified threshold, determining the problem type of the battery pack 200; and issuing a corresponding alarm type according to the problem type of the battery pack 200.

[0074] Among them, after the controller obtains the response signal of the pressure-sensitive structure 2 to the applied pressure, the controller first analyzes the numerical level of the response signal of the pressure-sensitive structure 2, that is, compares the numerical level of the detected response signal with a preset specified threshold. When the numerical level of the detected response signal reaches the specified threshold, the problem type of the battery pack 200 at this time is determined, and then the controller issues a corresponding alarm type according to the determined problem type. In this way, it is beneficial to more accurately classify the battery problems, thereby improving the feedback fineness and further improving the accuracy of the detection element 100.

[0075] Moreover, for the case of the degree of bumping that does not involve internal short-circuit of the electrode core inside the battery cell 202 (where there are no abnormal changes in electrical parameters such as voltage and temperature, and traditional detection elements cannot achieve alarm through electrical parameters), the embodiments in this case have a lower false alarm rate for micro-bumping by directly sensing the mechanical force transmitted by the tray 201. In addition, the signal responses of different degrees of bumping can be obtained through experiments, the response values are matched with the damage degree of the battery cell 202, and the alarm information is preset in grades. According to some alternative embodiments of the present invention, in combination with Figure 7 As shown, there are multiple pressure-sensitive structures 2, and the response signal of the pressure-sensitive structure 2 includes the piezoelectric or piezoresistive signal response threshold of the pressure-sensitive structure 2 and the position number of the pressure-sensitive structure 2; the steps of issuing a corresponding alarm type according to the response signal of the pressure-sensitive structure 2 include: issuing an alarm type corresponding to the position number.

[0076] Among them, the response signal of the pressure-sensitive structure 2 can be the position number of the pressure-sensitive structure 2, that is, by independently collecting the response signals of multiple pressure-sensitive structures 2, the controller can analyze the specific position number of the pressure-sensitive structure 2. By comparing with the actual position of the battery cell 202, the battery cell 202 with problems can be successfully located, thereby improving the convenience of repairing and replacing the battery cell 202.

[0077] Compared with the traditional forms of warning liquid leakage by using gas detection, humidity detection, liquid detection, characteristic parameter detection (such as shell voltage, insulation resistance, etc.), and conductive characteristics, the embodiments in this case can expand the liquid leakage positioning monitoring method, quickly concentrate and adsorb the flowing liquid and convert it into mechanical force, and sense the force through the mechanical sensing material. It can not only detect liquid leakage efficiently and sensitively, but also achieve liquid leakage positioning through distributed design.

[0078] Optionally, piezoelectric or piezoresistive signal response thresholds for different degrees of risk of collision or liquid leakage are obtained through preliminary experiments, and combined with the voltage drop ∆V of each battery cell 202 at a fixed acquisition frequency, the risk of collision or liquid leakage can be classified. Thus, an alarm strategy is preset in the controller, and the alarm categories can include: no liquid leakage in the battery cell 202 at the bottom of XX position due to collision, liquid leakage in the battery cell 202 at the bottom of XX position due to collision, internal short circuit in the battery cell 202 at the bottom of XX position due to collision, liquid leakage in the battery cell 202 at XX position, etc.

[0079] The electrical device according to the embodiment of the fourth aspect of the present invention includes the battery pack 200 of the above embodiment. Thus, the electrical device with this battery pack 200 can timely and accurately obtain information about liquid leakage and collision of the battery pack 200, thereby improving the safety of the electrical device and further enhancing the market competitiveness of the electrical device.

[0080] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0081] In the description of the present application, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0082] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0083] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A detection element (100), characterized in that, Comprising: A liquid-absorbing and swelling structure (1), which is adapted to swell after absorbing liquid; A pressure-sensitive structure (2), which is disposed on one side of the liquid-absorbing and swelling structure (1), and is adapted to detect the pressure from the liquid-absorbing and swelling structure (1) on one side and the pressure on the other side.

2. The detection element (100) according to claim 1, characterized in that, The pressure-sensitive structure (2) includes: A first pressure-sensitive layer (21), which is disposed on one side of the liquid-absorbing and swelling structure (1), and is adapted to detect the pressure from the liquid-absorbing and swelling structure (1); A second pressure-sensitive layer (22), which is disposed on the side of the first pressure-sensitive layer (21) away from the liquid-absorbing and swelling structure (1), and is adapted to detect the pressure from the side away from the first pressure-sensitive layer (21).

3. The detection element (100) according to claim 2, characterized in that, The response signals of the first pressure-sensitive layer (21) and the second pressure-sensitive layer (22) are different; and / or The response times of the first pressure-sensitive layer (21) and the second pressure-sensitive layer (22) are different.

4. The detection element (100) according to claim 2, characterized in that, The pressure-sensitive structure (2) further includes: A buffer layer (23), which is respectively connected to the first pressure-sensitive layer (21) and the second pressure-sensitive layer (22) and is located between the first pressure-sensitive layer (21) and the second pressure-sensitive layer (22), and is adapted to elastically deform under an external force.

5. The detection element (100) according to claim 4, characterized in that, Further comprising: A housing (3), which forms a receiving cavity (31), the liquid-absorbing and swelling structure (1) is disposed at one end of the housing (3), and the liquid-absorbing and swelling structure (1) is at least partially disposed in the receiving cavity (31), the first pressure-sensitive layer (21), the buffer layer (23) and the second pressure-sensitive layer (22) are disposed in the receiving cavity (31), and the second pressure-sensitive layer (22) is disposed at the other end of the housing (3).

6. The detection element (100) according to claim 5, characterized in that, The liquid-absorbing and swelling structure (1) and the second pressure-sensitive layer (22) are connected to the inner wall of the receiving cavity (31) in the circumferential direction, and the first pressure-sensitive layer (21) and the buffer layer (23) are spaced from the inner wall of the receiving cavity (31).

7. The detection element (100) according to claim 1, characterized in that, The liquid-absorbing and swelling structure (1) includes: A gel layer (11), the pressure-sensitive structure (2) is disposed on one side of the gel layer (11); A capillary pore layer (12), which is disposed on the other side of the gel layer (11), the capillary pore layer (12) is provided with a plurality of capillary pores, and the plurality of capillary pores extend in the thickness direction of the capillary pore layer (12), and the capillary pores are adapted to quickly absorb liquid by capillary action and guide the liquid to flow to the gel layer (11).

8. The detection element (100) according to claim 7, characterized in that, The thickness of the capillary pore layer (12) is H1, and H1 satisfies the relation: 1.5 mm ≤ H1 ≤ 3 mm; and / or The thickness of the gel layer (11) is H2, and H2 satisfies the relation: 0.1 mm ≤ H2 ≤ 1 mm.

9. The detection element (100) according to claim 7, characterized in that, The diameter of the capillary pore is d, and d satisfies the relation: 0.1 μm ≤ d ≤ 5 μm; and / or The porosity of the capillary pore is a, and a satisfies the relation: 30% ≤ a ≤ 70%.

10. The detection element (100) according to claim 7, characterized in that, The crosslinking degree of the gel layer (11) is b, and b satisfies the relational expression: b ≤ 2%; and / or The porosity of the gel layer (11) is c, and c satisfies the relational expression: 30% ≤ c.

11. A battery pack (200), characterized in that, Comprising: A tray (201); A battery cell (202), the battery cell (202) being disposed above the tray (201); The detection element (100) according to any one of claims 1-10, the detection element (100) being disposed between the battery cell (202) and the tray (201), and the liquid absorption and expansion structure (1) being located between the battery cell (202) and the pressure-sensitive structure (2).

12. The battery pack (200) according to claim 11, characterized in that, The number of the battery cells (202) is multiple, the number of the detection elements (100) is multiple, and the multiple detection elements (100) are distributed in a matrix on the tray (201), and each detection element (100) corresponds to at least one battery cell (202).

13. The battery pack (200) according to claim 12, characterized in that, Further comprising: A controller, the controller being electrically connected to the multiple pressure-sensitive structures (2) respectively, and the controller being configured to issue different alarm types according to different response signals of the multiple pressure-sensitive structures (2).

14. The battery pack (200) according to claim 11, wherein, The detection element (100) is disposed between the top surface of the tray (201) and the bottom surface of the battery cell (202).

15. The battery pack (200) according to claim 11, wherein, An installation groove (2011) is provided at the top of the tray (201), and the detection element (100) is disposed in the installation groove (2011).

16. A detection method for the battery pack (200) according to any one of claims 11-15, characterized in that, Comprising the following steps: Obtaining the response signal of the pressure-sensitive structure (2); According to the response signal of the pressure-sensitive structure (2), issuing a corresponding alarm type.

17. The detection method of the battery pack (200) according to claim 16, characterized in that, The step of issuing a corresponding alarm type according to the response signal of the pressure-sensitive structure (2) includes: Analyzing the numerical level of the response signal of the pressure-sensitive structure (2); When the numerical level of the pressure-sensitive information reaches a specified threshold, determining the problem type of the battery pack (200); According to the problem type of the battery pack (200), issuing a corresponding alarm type.

18. The detection method of the battery pack (200) according to claim 16, characterized in that, The pressure-sensitive structures (2) are multiple, and the response signals of the pressure-sensitive structures (2) include the piezoelectric or piezoresistive signal response thresholds of the pressure-sensitive structures (2) and the position numbers of the pressure-sensitive structures (2); The step of issuing a corresponding alarm type according to the response signal of the pressure-sensitive structure (2) includes: Issuing an alarm type corresponding to the position number.

19. An electrical device, characterized in that, Comprising: The battery pack (200) according to any one of claims 11-15.

Images