Lithium-ion battery expansion measurement components, systems, and testing methods

Abstract

This invention belongs to the field of lithium battery testing, specifically relating to a lithium-ion battery expansion measurement component, system, and testing method. The lithium-ion battery expansion measurement component includes a lower base, a lithium battery mounted on the lower base, an upper base, and an airbag fixture mounted on the upper base. The lithium-ion battery expansion measurement component and system provided by this invention can accurately provide constant temperature and pressure loads according to different experimental requirements. Simultaneously, the airbag fixture applies a uniformly distributed load to the lithium battery, thereby eliminating measurement errors caused by unevenness on the lithium battery surface, improving measurement accuracy, and obtaining the evolution process of lithium battery volume expansion under predetermined temperature and pressure conditions.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery testing, specifically relating to a lithium-ion battery expansion measurement component, system, and testing method. Background Technology

[0002] Because lithium-ion batteries inevitably undergo volume deformation during charging and discharging, this phenomenon, under the constraint of limited external space, transforms into the force exerted by battery expansion on the external structure. Simultaneously, the reaction force from the external structure further influences the battery's structure, thereby affecting the electrochemical reaction process and either promoting or inhibiting it. Therefore, it is urgent to understand the volume deformation characteristics of lithium-ion batteries to provide reliable theoretical and experimental support for the design of both the battery itself and its external structure.

[0003] Meanwhile, issues such as volume deformation, battery structure design, and manufacturing processes inherent in lithium-ion batteries ultimately lead to uneven battery thickness. This uneven thickness directly affects the accuracy of battery thickness measurement when using conventional fixtures; moreover, conventional fixtures can cause uneven force on the battery, further affecting battery performance.

[0004] The experimental testing methods commonly used for the volume deformation of lithium-ion batteries mainly include two aspects:

[0005] (1) Direct method: The thickness change of lithium-ion battery is directly measured by displacement measurement sensors such as displacement gauges, or the thickness change of battery is tested after applying a certain pre-pressure through a pressure device. Chinese patent CN209470684U "Power Battery Thickness Measurement Device" adopts this method. However, this device does not consider the influence of battery temperature and uneven battery surface on the thickness measurement accuracy. In addition, Chinese patent CN216956292U "A Test Fixture for Battery Expansion Coefficient" uses a spring to apply a pseudo-constant pressure state and calculates the battery expansion coefficient by measuring the displacement of the clamping plate.

[0006] (2) Indirect method: Under constant displacement, the pressure on the clamp is measured instead of displacement test. Chinese patents that adopt this idea include CN216433334U "Expansion force test fixture", CN213956639U "A battery expansion force test fixture", CN206074165U "A battery expansion force test fixture", etc.

[0007] The above testing methods do not fully consider environmental factors (temperature, pressure) and intrinsic factors (such as surface unevenness caused by design and manufacturing, and in-plane non-uniformity that may exist after battery formation) that affect the performance of lithium-ion batteries. Therefore, in order to conduct in-depth research on the performance of lithium-ion batteries themselves and strictly control environmental variables, it is essential to design a real-time lithium-ion battery thickness measurement system that is based on long-term testing and can provide uniform load with temperature and pressure control. Summary of the Invention

[0008] The purpose of this invention is to provide a lithium-ion battery expansion measurement component, system, and testing method.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A lithium-ion battery expansion measurement assembly includes a lower base, a lithium battery disposed on the lower base, an upper base, and an airbag fixture disposed on the upper base.

[0011] Preferably, the airbag fixture includes an upper clamp, a lower clamp, and an airbag disposed between the upper clamp and the lower clamp; the upper clamp, the airbag, and the lower clamp are connected to the upper base. Preferably, the edges of the upper clamp and the airbag, and the lower clamp are connected to the upper base by bolts.

[0012] Preferably, a rubber pad is provided between the upper clamp and the lower clamp and the airbag.

[0013] Preferably, the lower clamp is a frame mechanism, the shape of the lower clamp is matched with the shape of the lithium battery, and the lower clamp is arranged parallel to the lithium battery.

[0014] Preferably, a liquid cooling plate is disposed between the lithium battery and the lower base. The liquid cooling plate is connected to the liquid cooling system through a liquid cooling plate inlet and a liquid cooling plate outlet;

[0015] Preferably, the lithium battery is connected to the charging and discharging fixture, and more preferably, the charging and discharging fixture is connected to the charging and discharging system.

[0016] Preferably, the upper base is connected to the extensometer via an upper bracket, and a lower bracket is provided on the lower base.

[0017] This application also includes a lithium-ion battery expansion measurement system, comprising a mounting assembly and the lithium-ion battery expansion measurement assembly.

[0018] Preferably, the mounting components include a lower base mounting component and an upper base mounting component;

[0019] Preferably, the lower base mounting assembly includes an operating table, an electro-hydraulic servo actuator mounted on the operating table, and a lower base mounting base connected to the electro-hydraulic servo actuator; the lower base mounting base is connected to the lower base.

[0020] Preferably, the upper base mounting assembly includes a sensor base, an upper base mounting seat connected to the upper base, and a pressure sensor disposed between the sensor base and the upper base mounting seat.

[0021] Preferably, the mounting assembly further includes a mounting bracket; the mounting bracket includes multiple columns mounted on the operating table and a top beam connecting the multiple columns; preferably, a crossbeam is connected to two of the columns; the sensor base is connected to the crossbeam; preferably, a limit post is provided between the top beam and the operating table; a limit block is provided on the limit post.

[0022] Preferably, the lithium-ion battery expansion measurement system further includes a control system, which includes a testing machine control system connected to an electro-hydraulic servo actuator, an extensometer, and a pressure sensor.

[0023] This invention also includes a method for measuring the expansion of a lithium-ion battery, employing a lithium-ion battery expansion measurement system; the method comprises the following steps: at a certain temperature, pressure is applied to the lithium-ion battery using an airbag fixture; the thickness of the battery is measured using an extensometer; after measuring the thickness, the lithium-ion battery is connected to a charge-discharge system via a discharge fixture, and charge-discharge cycles are performed on it, continuously recording the thickness change value to obtain the expansion rate. Preferably, a liquid cooling plate is used to control the temperature; preferably, a pressure sensor is used to track the applied pressure in real time.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] This application utilizes an airbag fixture design to apply a uniform load to the lithium-ion battery, eliminating measurement errors caused by uneven battery surface. By employing the parallelism between the lower clamp and the lithium battery, and its adaptable frame structure, the uneven loading problem introduced by the testing device to the lithium-ion battery is eliminated. A liquid cooling plate beneath the lithium battery provides a constant temperature environment; by controlling the temperature of the liquid cooling plate, a predetermined temperature field is applied to the lithium-ion battery, achieving strict temperature control during cycling. An electro-hydraulic servo actuator provides precise displacement control based on the volume deformation of the lithium-ion battery, ensuring the stability of the lithium-ion battery during long-term testing.

[0026] The lithium-ion battery expansion measurement component provided by this invention uses an airbag to apply a uniform load to the lithium battery, thereby eliminating measurement errors caused by unevenness of the lithium battery surface; it can strictly control and maintain the accuracy of the external pressure conditions of the lithium-ion battery throughout the entire test cycle.

[0027] The lithium-ion battery expansion measurement component provided by the present invention contacts the main surface of the lithium-ion battery with a liquid cooling plate, and applies a predetermined temperature field to the lithium battery by controlling the temperature of the liquid cooling plate, thereby achieving a strict temperature control process for the lithium-ion battery during cycling.

[0028] The lithium-ion battery expansion measurement component provided by the present invention contacts the main surface of the lithium-ion battery with a liquid cooling plate, and applies a predetermined temperature field to the lithium battery by controlling the temperature of the liquid cooling plate, thereby achieving a strict temperature control process for the lithium-ion battery during cycling.

[0029] The electro-hydraulic servo actuator provided by this invention provides precise displacement control based on the volume deformation of the lithium-ion battery and ensures the stability of the lithium-ion battery during long-term testing.

[0030] The lithium-ion battery expansion measurement system provided by this invention can accurately provide a uniformly distributed load under constant temperature and pressure according to different experimental requirements. Simultaneously, it improves measurement accuracy and obtains the evolution process of lithium battery volume expansion under predetermined temperature and pressure conditions. This provides a simple, rapid, high-precision, and quantifiable real-time measurement method for in-depth research on the volume deformation law of lithium-ion batteries during charging and discharging processes and for optimizing the internal and external structural design of batteries. Attached Figure Description

[0031] Figure 1 A schematic diagram of a lithium-ion battery expansion measurement assembly according to one embodiment of the present invention is shown;

[0032] Figure 2 A schematic diagram of an airbag fixture for a lithium-ion battery expansion measurement assembly according to one embodiment of the present invention is shown.

[0033] Figure 3 A schematic diagram of a lithium-ion battery expansion measurement system according to one embodiment of the present invention is shown.

[0034] Figure 4 A connection diagram of a control system according to one embodiment of the present invention is shown. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0037] In the description of this patent, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this patent according to the specific circumstances.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0039] Please see Figures 1-2 The diagram shows a structural embodiment of the present invention. Figure 1-2 A lithium-ion battery expansion measurement assembly is shown, including a lower base 402, a lithium battery 6 disposed on the lower base, an upper base 401, and an airbag fixture disposed on the upper base.

[0040] The airbag fixture includes an upper clamp 302, a lower clamp 303, and an airbag 301 disposed between the upper and lower clamps. The upper clamp, the edge of the airbag, and the lower clamp are connected to the upper base by bolts 304. Rubber pads 305 are provided between the upper and lower clamps and the airbag. The lithium battery is a pouch cell or a prismatic cell, but is not limited to these battery types.

[0041] The upper clamp 302, lower clamp 303, and rubber pad 305 are sequentially arranged and secured using bolts 304. The lower clamp is a frame mechanism, and its shape matches the shape of the lithium battery. The lower clamp is arranged parallel to the lithium battery; the opening size of the lower clamp should match the test object, therefore, lithium-ion batteries of different sizes require airbag fixtures of corresponding sizes.

[0042] In this embodiment, the airbag is formed by inflating and heat-sealing an aluminum-plastic film. Holes are required at the sealed edges to allow bolts to pass through. After being protected by two layers of rubber pads, the airbag is placed inside the upper and lower clamps and secured with bolts.

[0043] A liquid cooling plate is disposed between the lithium battery and the lower base. The liquid cooling plate is connected to an external liquid cooling system through a liquid cooling plate inlet 202 and a liquid cooling plate outlet 203; it operates independently.

[0044] The lithium battery is connected to the charging / discharging fixture 7. The charging / discharging fixture is connected to the charging / discharging equipment and operates independently.

[0045] The upper base is connected to the extensometer 5 via the upper bracket 403, and the lower base is provided with a lower bracket 404. The lower bracket 404 has a displacement measuring platform that is aligned with the extensometer 5. The probe of the extensometer and the displacement measuring platform can measure the expansion thickness.

[0046] The present invention also includes a lithium-ion battery expansion measurement system, comprising a mounting assembly and the lithium-ion battery expansion measurement assembly. The mounting assembly includes a lower base mounting assembly and an upper base mounting assembly;

[0047] like Figure 3 As shown, the lower base mounting assembly includes an operating table 110, an electro-hydraulic servo actuator 113 mounted on the operating table 110, and a lower base mounting base connected to the electro-hydraulic servo actuator; the lower base mounting base 115 is connected to the lower base; the lower base as a whole is fixed to the lower base mounting base 115 by a lower base mounting pin 116 and a fastening screw 117; the lower clamp mounting base 115 and the electro-hydraulic servo actuator 113 are fixed to the operating table 110 by bolts;

[0048] The upper base mounting assembly includes a sensor base 111, an upper base mounting seat 114 connected to the upper base, and a pressure sensor 112 disposed between the sensor base 111 and the upper base mounting seat 114. The upper base mounting seat 114 is connected to the upper base by fastening screws 117 and upper base mounting pins 116; the upper clamp mounting seat 114 and the pressure sensor 112 are combined as a whole and fixed to the crossbeam 106 of the mounting bracket by bolts.

[0049] The mounting assembly also includes a mounting bracket; the mounting bracket includes multiple columns 102 mounted on the operating table and a top beam connecting the multiple columns; a rubber pad 103 is provided on the operating table; a crossbeam 106 is connected to two of the columns; the sensor base 111 is connected to the crossbeam 106; a limit post 108 is provided between the top beam and the operating table; a limit block 107 is provided on the limit post. The crossbeam 106 is controlled to slide up and down on the columns 102 via a manual operating panel 109 for coarse pre-measurement distance adjustment. The limit post 108 remains parallel to the columns 102, and the limit block 107 limits the maximum displacement distance of the crossbeam 106 to protect the equipment. An emergency stop knob 104 is mainly used to interrupt the test in an emergency; a base 105 is provided at the bottom of the operating table.

[0050] The lithium-ion battery expansion measurement system also includes a control system; the control system includes a testing machine control system connected to an electro-hydraulic servo actuator, an extensometer, and a pressure sensor. The testing machine control system of this application can be an electronic creep endurance testing system.

[0051] A method for measuring the expansion of a lithium-ion battery, using the aforementioned lithium-ion battery expansion measurement system, includes the following steps: at a certain temperature, pressure is applied to the lithium-ion battery using an airbag fixture; the extensometer data is first reset to zero; then the lithium-ion battery is connected to a charge-discharge system via a discharge clamp and subjected to charge-discharge cycles; during this process, the extensometer continuously records the thickness change value, thus obtaining the battery expansion amount.

[0052] Specifically, the steps include: 1) controlling the movement of the crossbeam and applying a uniform pre-pressure to the lithium-ion battery through the airbag fixture; 2) turning on the liquid cooling system and applying a constant temperature to the lithium-ion battery through the liquid cooling plate; 3) after the pre-pressure and temperature stabilize, first zeroing the extensometer data, then connecting the lithium-ion battery to the charging and discharging system through the discharge fixture and performing a charging and discharging cycle. During this process, the extensometer continuously records the thickness change value, i.e., the battery expansion amount; 4) when the battery thickness changes, the pressure sensor detects the pressure change and transmits the signal to the control system. The control system controls the electro-hydraulic servo actuator to move to maintain a constant pressure value. This displacement value is measured and recorded by the extensometer.

[0053] This application utilizes an airbag fixture design to apply a uniform load to the lithium-ion battery, eliminating measurement errors caused by uneven battery surface. By employing the parallelism between the lower clamp and the lithium battery, as well as the adaptable frame structure, the uneven loading problem introduced by the testing device to the lithium-ion battery is eliminated.

[0054] The liquid cooling plate beneath the lithium battery provides a constant temperature environment. By controlling the temperature of the liquid cooling plate, a predetermined temperature field is applied to the lithium battery, achieving strict temperature control during the cycling process. The electro-hydraulic servo actuator provides precise displacement control based on the volume deformation of the lithium battery and ensures the stability of the lithium-ion battery during long-term testing.

[0055] This invention provides a lithium-ion battery expansion measurement component and system, capable of accurately providing constant temperature and pressure loads according to different experimental requirements. Simultaneously, it employs an airbag to apply a uniformly distributed load to the lithium battery, thereby eliminating measurement errors caused by unevenness on the lithium battery surface, improving measurement accuracy, and obtaining the evolution process of lithium battery volume expansion under predetermined temperature and pressure conditions. This provides a simple, rapid, high-precision, and quantifiable real-time measurement method for in-depth research on the volume deformation law of lithium-ion batteries during charging and discharging processes and for optimizing the internal and external structural design of batteries.

[0056] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A lithium-ion battery expansion measurement system, characterized in that, This includes mounting components and lithium-ion battery expansion measurement components; The lithium-ion battery expansion measurement assembly includes a lower base, a lithium battery disposed on the lower base, an upper base, and an airbag fixture disposed on the upper base. The airbag fixture includes an upper clamp, a lower clamp, and an airbag disposed between the upper clamp and the lower clamp; the upper clamp, the airbag, and the lower clamp are connected to the upper base; Rubber pads are provided between the upper clamp and the lower clamp and the airbag; The lower clamp is a frame mechanism, and the shape of the lower clamp is matched with the shape of the lithium battery; the lower clamp is arranged parallel to the lithium battery. A liquid cooling plate is provided between the lithium battery and the lower base; the liquid cooling plate is connected to the liquid cooling system through a liquid cooling plate inlet and a liquid cooling plate outlet; The lithium battery is connected to the charging / discharging fixture; the charging / discharging fixture is connected to the charging / discharging system. The upper base is connected to the extensometer via an upper bracket, and a lower bracket is provided on the lower base; The mounting components include a lower base mounting component and an upper base mounting component; The lower base mounting assembly includes an operating table, an electro-hydraulic servo actuator mounted on the operating table, and a lower base mounting base connected to the electro-hydraulic servo actuator; the lower base mounting base is connected to the lower base. The upper base mounting assembly includes a sensor base, an upper base mounting seat connected to the upper base, and a pressure sensor disposed between the sensor base and the upper base mounting seat.

2. The lithium-ion battery expansion measurement system according to claim 1, characterized in that, The mounting assembly further includes a mounting bracket; the mounting bracket includes multiple columns mounted on the operating platform and a top beam connecting the multiple columns; a crossbeam is connected to two of the columns; and the sensor base is connected to the crossbeam.

3. The lithium-ion battery expansion measurement system according to claim 2, characterized in that, A limit post is provided between the top beam and the operating table; a limit block is provided on the limit post.

4. The lithium-ion battery expansion measurement system according to any one of claims 1-3, characterized in that, It also includes a control system; the control system includes a testing machine control system connected to an electro-hydraulic servo actuator, an extensometer, and a pressure sensor.

5. A method for measuring the expansion of a lithium-ion battery, characterized in that, The lithium-ion battery expansion measurement system according to any one of claims 2-3 is used; The process includes the following steps: At a certain temperature, pressure is applied to the lithium-ion battery using an airbag fixture. First, the extensometer data is zeroed. Then, the lithium-ion battery is connected to the charge-discharge system via a discharge clamp, and it undergoes charge-discharge cycles. During this process, the extensometer continuously records the thickness change value, thus obtaining the battery expansion amount.

6. The battery expansion measurement method according to claim 5, characterized in that, Includes the following steps: 1) Control the movement of the crossbeam and apply uniform pre-pressure to the lithium-ion battery through the airbag fixture; 2) Turn on the liquid cooling system to apply a constant temperature to the lithium-ion battery through the liquid cooling plate; 3) After the pre-pressure and temperature stabilize, first reset the extensometer data to zero, then connect the lithium-ion battery to the charging and discharging system through the discharge clamp and perform charging and discharging cycles. During this process, the extensometer continuously records the thickness change value, that is, the expansion amount of the battery.

7. The battery expansion measurement method according to claim 6, characterized in that, When the battery thickness changes, the pressure sensor detects the change in pressure value and transmits the signal to the control system. The control system then controls the electro-hydraulic servo actuator to move in order to maintain a constant pressure value. This displacement value is measured and recorded by an extensometer.

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